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Clinical results of the one-bone forearm
Clinical Results of the One-Bone Forearm Charles A. Peterson II, MD, Rochester, MN, Shinya Maki, MD, Kagoshima, Japan, Michael B. Wood, MD, Rochester, MN Between 1973 and 1991, 19 patients underwent creation of a one-bone forearm at our institution as treatment for radioulnar instability secondary to trauma ("type 1" patients) or tumor resection or congenital deformity ("type 2" patients). Seventeen had failed previous reconstruction attempts. Ten one-bone forearms were constructed in neutral rotation, and nine in varying pronation (mean, 24~ The distal ulna was absent or excised at the time of surgery in nine patients, partially excised in two, and shortened in one. At a mean follow-up interval of 42 months, the primary union rate was 68%, and the secondary rate was 74%. Using a rating scale devised for this study, 37% excellent, 32% good, 26% fair, and 5% poor results were noted. Poor results were statistically associated with previous trauma (type 1 patients), infection, severe nerve injury, and multiple previous surgical procedures. This is a retrospective study, and because of the limitations of such studies, no correlation of results with forearm rotational position, preoperative wrist or elbow dysfunction, fusion location, distal ulna excision or synostosis union was noted. Significant complications were noted in 10 patients, with a higher rate in type 1 patients. Although one-bone forearm construction remains a viable salvage option for forearm instability in selected patients, results may be less predictable than previously reported. (J Hand Surg 1995;20A:609-618.)
Forearm instability in the setting of structural bone defects presents a unique reconstructive challenge. Trauma, congenital deformity, or prior surgery may result in symptomatic angular, axial, or torsional radioulnar instability. Such laxity implies incompetence of radial or ulnar diaphyseal architecture, the interosseous soft-tissues, and/or the proximal or distal radioulnar joints and their associated ligamentous complexes. Unstable segmental forearm bone defects or chronic nonunion may be complicated by tissue disruption or sepsis, neurologic compromise, and wrist
From the Departmentof Orthopedics,MayoClinic,Rochester,MN, the Department of Hand Surgery, KagoshimaCity, Kagoshima, Japan. Received for publicationApril 29, 1994; accepted in revised form Feb. 16, 1995. No benefitsin any formhavebeen receivedor will be receivedfrom a commercialparty related directlyor indirectlyto the subject of this article. Reprintrequests:MichaelB. Wood,MD, Departmentof Orthopedics E-14, MayoClinic,200 First StreetSW, Rochester,MN 55905. and
or elbow dysfunction. For such instability, nonoperative management includes functional bracing or activity modification. C o m m o n surgical options include simple internal fixation and bone-grafting; structural bone-graft or prosthetic segmental-spacer interposition; or osteotomy of the adjacent radius or ulna, followed by shortening and fixation. Despite the reported success of these measures, there are clinical situations where forearm stabilization is most efficaciously achieved through surgical creation of a "one-bone forearm" (OBF) via radioulnar synostosis, as described initially by Hey Groves,' and subsequently by othersY 6 The theory behind this procedure has been outlined by Vitale, in that "the ulna 'makes' the elbow; the radius 'makes' the wrist. ''4 Thus, the procedure attempts to create a single, stable, osseous bridge between the ulnohumeral and radiocarpal joints. However, despite multiple reports, there remains no clear agreement as to the specific indications, operative techniques, position of synostosis, or expected outcome. We report our experience with one-bone forearm conThe Journal of Hand Surgery
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610 Petersonet al. / One-Bone Forearm struction in a series of patients not considered candidates for other reconstructive procedures, with particular emphasis on these areas. P a t i e n t s a n d Methods Retrospective review of our institution's Patient Registry identified 23 patients who underwent surgical radioulnar synostosis between 1973 and 1991. Two additional patients underwent distal radial resection followed by ulnocarpal fusion. Six patients were excluded due to inadequate follow-up information; four had died from complications of metastatic oncologic disease and two failed to return as requested. All clinical records, operative reports, x-ray films, and a mailed follow-up questionnaire for the remaining cohort were retrospectively analyzed by a single reviewer. Questionnaire data was used only to confirm the findings recorded at most recent clinical follow-up examination. Nineteen patients had complete clinical records. Six of these completed follow-up questionnaires. The cohort included 11 men and 8 women with a mean age at the time of procedure of 28 years (range, 3-64) (Table 1). Four patients were skeletally immature at the time of the procedure. Thirteen cases involved the left forearm. Seventeen patients were right-hand dominant, and the dominant extremity was fused in eight cases. Eight patients were manual laborers prior to treatment, of whom two had work-related injuries under worker's compensation jurisdiction. The mean time from procedure to final clinical review was 42 months (range, 6-145) (Table 1). Patients were grouped by pathologic etiology. Type 1 patients had bony instability secondary to trauma. Type 2 patients had atraumatic instability secondary to prior osseous tumor resection or congenital deformity. Thirteen type 1 and six type 2 (five tumor, one congenital) cases were noted. Primary indications for conversion to a one-bone forearm included significant, symptomatic, angular, axial, or rotatory radioulnar instability in the setting of segmental bone loss or refractory nonunion (Fig. 1). Additionally, 13 patients had failed previous reconstruction attempts. In all cases, rotation-preserving reconstructive options were considered likely to be unsuccessful. Thus, the OBF procedure was used as a salvage technique for these patients. Relative indications included the presence of radiohumeral joint dysfunction or patient choice after discussion of more complex reconstruction alternatives. Ulnohumeral soft-tissue contracture, low-grade degenerative articular change, or wrist dysfunction were not considered routine contraindications.
Figure 1. Radioulnar instability after distal ulnar resection was performed for a deforming, painful osteochondroma.
Bony pathology was isolated to the radius in six patients, to the ulna in four, and both in nine. Fourteen patients (eight type 1, six type 2) had instability secondary to segmental loss (six radial, four ulnar, four both), with a mean gap of 7.7 cm (range, 2-15). Five patients (all type 1) had chronic, refractory nonunion (one radial, one ulnar, three both).
Post-traumatic Instability (Type 1) In the 13 cases with type 1 post-traumatic instability, 11 had previously sustained open fractures: 3 involving the radius alone, 6 involving both radius and ulna, and 2 involving the radius or ulna and the carpus in combination. Using the open-fracture classification of Gustillo and Anderson, ~7 there were three grade II, two grade III A, five grade III B, and one grade III c fractures. Two patients had instability after relatively lesssevere trauma. One suffered a closed distal radius fracture with malunion and distal radioulnar joint (DRUJ) instability; the second fell onto an outstretched hand, which resulted in lunotriquetral ligament tear and DRUJ disruption. Both had symptomatic radioulnar instability after multiple failed bone and soft-tissue reconstruction attempts. Eight of the type 1 patients had a severe associated injury to the brachial plexus, ulnar, radial, or median nerves in the ipsilateral extremity that required primary repair, interposition grafting, neurolysis, or tendon transfers.
Instability After Oncologic Resection or Congenital Deformity (Type 2) Of the five patients with instability after primary bone tumor resection, two had distal radial giant cell tumors, and one respectively had proximal radial grade-1 chondrosarcoma or Ewing's sarcoma. One
The Journal of Hand Surgery/ Vol. 20A No. 4 July 1995 611 patient had instability and a chronically dislocated radial head after resection of the distal ulna for a deforming, painful osteochondroma. The single procedure for congenital deformity involved severe radioulnar bowing with chronic posterolateral radial-head dislocation and loss of motion requiring proximal radius and distal ulnar resection.
Instability With Associated Joint Dysfunction Preoperative elbow abnormality was present in 16 patients. The ulnohumeral joint alone was involved in four, the radiohumeral joint alone in three, and both in nine. All had soft tissue contractures with a mean extension/flexion arc of 30~ ~ and a mean proration/supination arc from neutral of 33o/53 ~ One patient showed early ulnohumeral degenerative change on x-ray films. No patient had gross ligamentous elbow instability. Three had previous radialhead resection, three had proximal-radius resection for tumor, two (previously mentioned) had a chronically dislocated, irreducible radial head, and one had a previous total-elbow arthroplasty that required revision/replantation for infection. Isolated wrist abnormality was present in three patients, and isolated DRUJ abnormality in four. Eight had combined wrist and DRUJ abnormality. Of the 11 patients with wrist abnormality, 8 had severe instability, secondary to bone or tissue loss in 6 and neurogenic weakness in 2. One patient each had previously undergone complete wrist arthrodesis, selected intracarpal fusion, or arthroscopic debridement of a triangular fibrocartilage complex tear. Of those patients with DRUJ abnormality, all had instability. Six had prior distal ulna resection for tumor resection or pain relief. In three others, a similar resection was performed during the OBF procedure.
Surgical Technique Operative technique varied between the five surgeons involved in treating this heterogeneous patient population. Surgical approach, architectural apposition of radius, ulna, and/or carpus, and fixation technique were determined individually based on preoperative bone stock and soft-tissue evaluation. Prior incisions were used if possible. A dorsal approach was used in seven cases, anterior in one, ulnar in five, and combined in six. The location of fusion involved the proximal third of the forearm in three cases, the middle in seven, and the distal third in nine. In 16 cases, the proximal ulna was coapted and fixed to the distal radius after subperiosteal exposure and cortical abrasion (Fig. 2). The remaining three patients underwent resection of the entire distal radius and portions of the carpus for tumor or trauma, requiring simultaneous wrist fusion. Free, vascularized fibula transfer was used in two of these forearms. Both were reconstructed with the fibula spanning from the remaining proximal ulna or radius to the third metacarpal base. In one of these
Prior Surgical Procedures Three patients were referred to our center with incomplete records of previous procedures. For the remaining 16 patients, the mean number of previous reconstructive procedures on the involved extremity was 4 (range, 0-18). Type 1 patients had a mean of seven previous procedures (range, 3-18); type 2 patients had a mean of one (range, 0-2). Ten type 1 patients had a history of deep infection. Seven had culture-positive osteomyelitis, two had deep softtissue abscesses, and one had an infected totalelbow arthroplasty. All had been treated and were thought clinically free of infection at the time of the OBF procedure.
Figure 2. One-bone forearm construct with synostosis of proximal ulna to distal radius in the same patient as Figure 1.
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Table 1.
Patient No./Age (years)
Follow-up (months)
Instability Etiology
Synostosis Pronation (degrees)
25
15
Trauma (Crush injury, segmental radius, soft-tissue loss)
29
63
Tumor (Proximal radial/ chondrosarcoma, s/p resect)
40
Proximal radial resected, F/E, P/S contracture
64
10
Trauma (Infected ulnar N/U, failed ORIF)
40
Radial head resected F/E, P/S contracture
3
6
51
5
Preoperative Elbow~Wrist Pathology F/E, P/S contracture, Wrist unstable
Congenital (ulnar/radial bowing)
0
Radial/head dislocated P/S contractnre
57
Tumor (Recurrent distal radial GCT, s/p wide resection)
0
Wrist instability after resection
19
18
Trauma (Open crush/Galeazzi fracture/DLC, resected distal ulna, osteomyelitis)
0
P/S contracture, wrist instability
23
9
30
F/E contracture
25
121
24
17
Trauma (Radial/ulnar segment defects after I+D post-trauma osteomyelitis)
15
F/E contracture, wrist weakness
10 35
13
Trauma (Crush, DRUJ unstable, multiple reconstruction attempts, infection)
30
F/E, P/S contracture, s/p wrist fusion
11 39
42
Trauma (Colle's malunion, multiple failed reconstruction attempts)
0
Ulnar wrist, DRUJ instability
12 31
17
Tumor (Distal radial GCT, s/p resection w/distal ulna/carpus)
5
F/E, P/S contracture Wrist instability
13 7
120
Trauma (Crush/lacerated radial ulnar defects, osteomyelitis, s/p I+D)
0
F/E, P/S contracture, Carpal resection, s/p soft-tissue arthroplasty
14 42
36
Trauma (Chronic N/U radial/ulna)
0
15 8
8
Tumor (Proximal radial/Ewing's sarcoma, s/p resect)
0
Proximal radial resection, instability
Trauma (Infxn. N/U ulna) Trauma (GSW elbow, s/p infxh TEA, proximal radial loss/unstable)
0
s/p TEA, Elbow F/E, P/S contractures, wrist weakness
16 24
145
Trauma (Segment defect radial/ulna)
0
F/E contracture, wrist instability
17 9
118
Tumor (Distal ulna OC, s/p resection)
0
Radial head dislocation F/E, P/S contracture
18 25
12
Trauma (Carpal instability, failed distal ulna resection)
20
P/S contracture, intracarpal instability and fusions
19/42
13
Trauma (Open fracture elbow, s/p multiple reconstruction attempts)
25
F/E, P/S contracture, proximal radius, distal ulna resection, TFCC tear
P/S, pronation/supination; F/E, flexion/extension; N/U, Nonunion; DRUJ, distal radioulnar joint; TFCC, triangular fibrocartilage complex; GCT, giant cell tumor; TEA, total elbow arthroplasty; OC, osteochondroma; ORIF, open reduction and internal fixation; DLC; dislocation; s/p, status/post; I+D, incision and drainage.
The Journal of Hand Surgery / Vol. 20A No. 4 July 1995
Individual Patient Data
History of Infection
No. Previous Procedures
Union
Complications
Score
No
N/A
Yes
No
2
Yes
Yes
N/A
Yes
4
No
0
Yes
10
No
2
No
Yes
8
Yes
Yes
4
No
Nonunion
Yes
N/A
Yes
Infected TEA
No
Infection (deep), nonunion
Yes
Radius fracture
No
No
Infection (deep), nonunion
No
Yes
Delayed union
Yes
Yes
Infection (deep)
Nonunion
Yes
Yes
18
6 Fixation plate pain
Loose pin, N/U ulnocarpal fusion
6
8 8
Yes
3
No
No
1
Yes
Yes
5
Yes
No
1
Yes
No
5
No*
Nonunion *union after revision ORIF
8
Yes
16
Yes
Hardware failure, recurrent ulnar nerve entrapment
6
7 8
Infection (superficial)
6 8
613
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two patients the proximal end of the fibular graft was fixated to the proximal ulna; in the second, fibula-toradius fixation was used, requiring simultaneous proximal radioulnar synostosis (Fig. 3). The third patient underwent carpal centralization and fusion to the distal ulna, followed by proximal radioulnar synostosis. The rotational position of the fusion was at neutral in 10 cases. The remaining nine forearms were fused in varying degrees of pronation with a mean of 24 ~ (range, 5~176 Fixation techniques were variable. Nine patients had cortical screw fixation alone, with a mean of 3 screws being used (range, 1-4); four had multiple Kirschner wires (K-wires) alone; two had external fixation with pins through both radius and ulna (one supplemented with K-wires); one had a single Steinman pin; one had a combination of screws and K-wires; and two had a dorsal neutralization plate supplemented with bicortical screws or cerclage wiring. The distal ulna was fully resected during the procedure in three patients, and partially, along with the distal radius, in two. One patient underwent 7 mm of intraoperative ulnar recession to prevent postoperative carpal impingement after radial shortening was noted during synostosis. Fourteen patients had autologous bone grafting at the fusion site. Morselized cancellous graft was used in all; six were supplemented with structural corticocancellous graft. One patient in an external fixator underwent open-technique grafting as described by Papineau/8 Three patients underwent free, vascularized fibular transfer. Two, as noted previously, were placed distal to the synostosis as part of concurrent wrist arthrodesis, and one at the actual synostosis site. Simultaneous procedures at the time of synostosis included wrist arthrodesis in three patients, tendon transfer or lengthening in three, soft tissue flap coverage in two, fibular transfer in three, ulnar neuroly-
sis in one, revision of a fourth metacarpal-hamate fusion in one, and distal ulnar resection or recession, as previously noted. Mean tourniquet time was 133 minutes, and the mean operative time was 254 minutes (range, 70-720). All patients except those with external fixation were protected in a long arm cast for a mean of 9 weeks postoperatively (range, 6-16 weeks), until radiographic and clinical evidence of synostosis consolidation were present. Progressive range-of-motion and strengthening exercises were then begun. Evaluation of Results
Clinical outcome at follow-up evaluation was measured and compared using a 10-point, subjective scoring system designed for this review, based on function, pain, and attainment of union (Table 2). Functional capability was assessed as follows: "near normal" patients reported no significant impairment in their use of the involved forearm. "Complex activity" function included those patients who reported definite impairment in forearm performance but who could still easily perform tasks beyond the "daily activity" level (e.g., manual labor, repetitive motor tasks, lifting more than 20 lbs. repetitively, etc.). "Activities of daily living" function allows patients to perform basic personal hygiene, drive a car, cook, and so on. "Minimal" function describes a forearm useless for most or all activities of daily living. Pain level was subjectively graded by patients in the follow-up questionnaire by choosing between none, mild, moderate, or severe. Union was judged by single-reviewer analysis of serial anteroposterior and lateral x-ray films. Overall outcomes were then graded by total score summation (Table 2).
Results
Figure 3. One-bone forearm construct with free, vascularized fibular transfer and associated "fibulocarpal" fusion.
Results obtained using the above scoring system are given in Table 1. Seven patients were rated as excellent; six, good; five, fair; and one, poor. In type 1 patients, nine had excellent or good results, compared with all six of the type 2 patients. The mean score for type 1 patients was 5.6 (range, 3-8), versus 8.0 (range, 6-10) in type 2 forearms. All patients, regardless of clinical score, were satisfied with their outcomes. Comparative statistical analysis was performed via Wilcoxon's exact test for ordinal variables using clin-
The Journal of Hand Surgery / Vol. 20A No. 4 July 1995
Table 2. Ten-point Scoring System For Clinical Results Category Functional capability
Pain level
Union
Level
Points
Near normal Complex activities Activities of daily living Minimal None Mild Moderate
6 4 2 0 3 2 1
Severe
0
Yes No
1 0
Grading system: 8-10 cumulative points = excellent; 6-7 points = good; 4-5 points = fair; 0-3 points = poor.
ical scores at follow-up evaluation. Factors associated with a poorer result included traumatic primary pathology (type 1 patients), two or more previous major reconstructive procedures, history of a severe nerve injury, and a history of previous infection (p <.05). No significant correlation with outcome was able to be shown for rotational position of fusion, location of fusion, distal ulnar excision, prior soft tissue injury (unless associated with infection), preoperative wrist or elbow abnormality, or postoperative nonunion. Eleven patients were employed prior to injury, and six (four manual laborers) returned to their previous employment, while three (two manual laborers) returned to different, less physically demanding jobs. Thus, only half of manual laborers were able to return to their previous level of employment. Two patients, both under worker's compensation jurisdiction, had not returned to work at the time of the follow-up evaluation. Range of motion and strength testing were not uniformly recorded at the follow-up evaluation. Ten patients had complications related to their synostosis, including nonunion, infection, hardware failure, and fracture. Nine involved post-traumatic cases; therefore, the major complication rate in the type 1 patient group was 69% versus 17% in the type 2 group (p <.05). Six patients (five type 1, one type 2) had nonunion, for an overall rate of 32%. Five of these occurred during the early postoperative course. Only one had sufficient symptoms to warrant revisional bone-grafting and fixation, and then progressed to union. The others, having achieved an increased degree of foreann stability via fibrous union, were effectively man-
615
aged with bracing and activity modification without further surgery. One patient with apparent clinical and radiographic union underwent hardware removal at 3 years. She subsequently developed a painless pseudarthrosis and was braced. Nonoperative management of these five nonunions resulted in good overall function with high patient satisfaction (Table 1). No statistical correlation of rotational position, synostosis location, fixation technique, or postoperative immobilization could be made with the presence of nonunion. Four patients developed three deep and one superficial postoperative infections. These occurred in three of the type 1 patients with a history of open fracture, and all had a history of previous infection. All resolved after debridement and parenteral antibiotic therapy. One patient sustained a radius fracture distal to the synostosis site 2 weeks after surgery while in a long arm cast. It was retrospectively noted that the radial cortex had been saucerized to allow insetting of the ulna during coaptation. We surmise the resultant stress riser led to mechanical failure despite protective immobilization. Union was achieved after internal fixation with a plate and screws. One patient, with preoperative ulnohumeral degenerative change, fractured all three bicortical fixation screws while in a cast (Fig. 4). After revisional fixation, he also progressed uneventfully to union. However, he returned a year later with increased arthritic symptoms and mild elbow instability, and is presently awaiting treatment. Three patients had minor complications. One patient had loosening of Steinman pin fixation and did well following pin reinsertion. One required subcutaneous ulnar plate removal for mechanical symptoms, and one had delayed union requiring functional bracing until union occurred. We were unable to ascertain the presence or degree of postoperative forearm shortening in the patient group. A mean of 1.2 further major reconstructive procedures had been performed on the operated extremity at the time of final follow-up evaluation (range, 0-5).
Discussion In 1921, Hey Groves 1 first described the use of radioulnar synostosis as a salvage procedure for failed bone-grafting of a distal radius nonunion. Using a specially designed lever, the proximal ulnar shaft was impacted into the distal radial metaphysis
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Peterson et al. / One-Bone Forearm
Figure 4. This fixation failure required revisional internal fixation to attain union.
after distal ulnar resection. Greenwood reported a similar technique in 1932 in a child after radial diaphysectomy for osteomyelitis, yet contended the distal ulna should be spared, rendering the wrist "perhaps more stable and possibly more mobile. ''2 Watson-Jones (1934) returned to distal ulnar resection for cosmesis and length-maintenance, asserting that wrist stability is retained by a bony buttress generated by the remaining ulnar periosteal tube? He was also the first to recommend a rotational position for fusion, that of 10 ~ pronation. Vitale (1952) reported good results in two children for congenital and postresection deformity, the first noted use of the technique for ulnar pathology. 4 In 1955, Murray outlined the use of step-cuts and intramedullary nail or lag-screw cortical fixation in two cases for achieving synostosis? Procedural indications included instability in the setting of pain, weakness, loss of rotation, or "massive bone loss associated with loss of the articulating joint surface. ''5 Lowe (1963) reported good results in seven patients fused in neutral or up to 45 ~ of supination. 6 All patients with documentation of postoperative limb length had shortening, with a mean of 2.3 inches. In the largest series to date, Reid and Baker (1973) reported 90% "good cosmetic and functional results" in 10 procedures with indeterminate follow-up periods. 7 The single failure was due to deep infection requiring debridement. Castle (1974) demonstrated apparently satisfactory long-term results in six cases of post-traumatic or infectious nonunion with accompanying soft-tissue defects using intramedullary-nail fixation. 8 A normal hand with normal radiocarpal and ulnohumeral joints was considered a prerequisite for a good result. Several authors have noted a potential benefit of synostosis versus other forms of reconstruction in the developing pediatric forearm. 4'9 Both proximal and
distal physes of the new forearm bone may be preserved to provide optimal length and growth potential. Most recently, pediatric case reports have noted successful use of radioulnar fusion as a primary or salvage procedure in congenital ulnar pseudarthrosis, either idiopathic or secondary to neurofibromatosis. 9-ll Finally, Dell and Sheppard (1984) have used vas, cularized fibular transfer and external fixation in the setting of infected radius or ulnar nonunion to create a stable one-bone forearm. 19 One of their four cases resulted in nonunion, requiring secondary bone grafting. A summary of the previously published results shown in Table 2 associates the OBF procedure with predictably good results. Limb shortening appears to be the only recurrent complication. However, to date these have been relatively small series, with anecdotal grading of postoperative function and variable follow-up periods. As previously mentioned, issues that remain unclear include surgical indications, the optimum rotational position of synostosis, the impact of associated elbow or wrist pathology, the need for resection of the ulnar head, and the rate of both acceptable outcome and complications. Viewing our results, two different populations become apparent, based on the etiology of forearm instability. Post-traumatic, type 1 patients underwent more previous surgery, had a higher incidence of prior infection, presented with poorer soft tissue and bone stock, and had overall poorer results with a higher complication rate than the type 2, nontrauma group. The greater degree of initial insult to the forearm in these cases may predicate a worse result regardless of reconstruction technique. Nevertheless, 9 of type 1 patients achieved an excellent or good result with synostosis as a salvage procedure, as compared with all patients in the type 2 group. The recommended position of forearm rotation in the literature has generally been one of neutral or
The Journal of Hand Surgery / Vol. 20A No. 4 July 1995
slight pronationY ,8 Morrey et al. 2~have defined the range of pronation supination needed for various daily tasks. Greater pronation is generally required for tasks involving interaction with the external environment, whereas greater supination aids in moving the hand normally about the body. Our results show no superiority of fusion in either neutral or pronation. We have no experience with fusion in supination as previously reported. 6,7 Shoulder rotation and abduction/adduction allow the neutral or pronated forearm to attain pronation, neutral, or even slight supination. Such adaptability may not be the case for the supinated forearm. However, as noted by Reid et al., some laborers may benefit from a position of supination in the nondominant hand to allow grasping of certain tools] Some patients may benefit from preoperative casting or bracing of the forearm in various degrees of rotation, allowing experimentation to determine optimum individual position. Previous reports have regarded preoperative ulnohumeral or wrist pathology as a contraindication to creation of OBE 4'5'8A4 Statistical analysis of our patients' clinical scores did not demonstrate worse results in such a setting. However, based on this patient population, we cannot predict accurately the result of radioulnar synostosis in the setting of severe intra-articular ulnohumeral pathology or instability. Significant radiohumeral dysfunction was a relatively favorable indication for surgery in our patients. Wrist instability was usually addressed at the time of surgery, which appeared to be an effective technique. Ipsilateral wrist fusion did not affect results. Previous authors have debated the question of distal ulnar resection with regard to wrist stability and cosmetic deformity.1-3 In five cases, we partially or fully resected, and in one case shortened, the distal ulna as part of the synostosis procedure. Additionally, the distal ulna had been previously resected in six cases. There was no correlation between excision/shortening and clinical outcome. No patient with distal ulnar retention complained of carpal impingement symptoms or cosmetic deformity postoperatively The high complication rate in these patients is disconcerting. As nearly all (90%) major complications occurred in the type 1, post-traumatic instability group, this may reflect the general severity of injury and the level of reconstructive challenge in these patients. Notably, all four cases of postoperative infection occurred in patients with a history of sepsis. Certainly the principles of adequate local tissue management--including prompt, aggressive debridement, antibiotic therapy, flap coverage of large
617
defects, staged reconstruction, and delayed closure of tenuous wounds--must be applied. The 32% rate of nonunion is higher than previously reported, ~9 and underscores the need for rigid fixation, aggressive bone grafting, and adequate postoperative immobilization after optimal soft-tissue control has been achieved. Interestingly, nonunion did not necessarily correlate with poor clinical results. The mean score for this group was 6.3, with two good, one fair, and one poor ranking, indicating a high degree of function with minimal or no pain. The relatively small size of our study population may limit statistical correlation of nonunion with functional outcome. Alternately, sufficient fibrous union may have been achieved in these forearms to limit pain and allow reasonable function despite lack of bony union. Radioulnar synostosis, or the creation of a onebone forearm, remains a useful technique for managing angular, axial, or rotatory radioulnar instability in the setting of significant or refractory osseous defects. Indications include a likelihood of failure of rotation-preserving techniques, failure of previous such methods, inability to perform resource-intensive procedures such as vascularized bone transfer 2~ or osteogenic bone transport if appropriate, or desire for a single, relatively simple procedure to regain a functional forearm lever. Preoperative radiohumeral joint dysfunction appears a favorable indication. Active infection or poor soft-tissue condition requires definitive management prior to synostosis. Pre-existing wrist dysfunction does not appear to affect outcome. Although no definite conclusions can be drawn from our data on whether significant intra-articular ulnohumeral pathology or instability are contraindications, we advise caution in this setting. The optimal rotational position of the forearm synostosis remains unclear. Preoperative trial bracing may be useful to allow informed patient choice regarding position. Rigid fixation and autologous bone graft should be used, and the extremity should be protected until clinical and radiographic evidence of union are present. Excision of the distal ulnar fragment appears not to affect the functional outcome. A subjective scoring system is presented to allow comparison of results. Severe trauma, a history of infection or severe nerve injury, and multiple previous procedures are associated with poorer results. Such patients have higher rates of postoperative complications, including nonunion, than previously reported, but still may be successfully salvaged by this technique.
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References 1. Hey-Groves EW, ed. Modern methods of treating fractures, 2nd ed. Bristol: John Wright and Sons, Ltd, 1921: 320. 2. Greenwood HH. Reconstruction of forearm after loss of radius. Br J Surg 1932;20:58-60. 3. Watson-Jones R. Reconstruction of the forearm after loss of radius. Br J Surg 1934;22:23-6. 4. Vitale CC. Reconstructive surgery for defects in the shaft of the ulna in children. J Bone Joint Surg 1952; 34A:804-9. 5. Murray RA. The one bone forearm. J Bone Joint Surg 1955;37A:366-70. 6. Lowe HG~ Radioulnar fusion for defects in the forearm bones. J Bone Joint Surg 1963;45B:351-9. 7. Reid RL, Baker GI. The single-bone forearm: a reconstructive technique. Hand 1973;5:214-9. 8. Castle ME. One bone forearm. J Bone Joint Surg 1974;56A: 1223-7. 9. Lloyd-Roberts GC. Treatment of defects of the ulna in children by establishing cross union with the radius. J Bone Joint Surg 1973;55B:327-30. 10. Maffulli N, Fixsen JA. Pseudarthrosis of the ulna in neurofibromatosis: a report of four cases. Arch Orthop Trauma Surg 1991; 110:204-7. 11. Hadlow V. Congenital pseudarthrosis of the ulna: a case report. Aust NZ J Surg 1979;49:100-4. 12. Ostrowski DM, Eilert RE, Waldstein G. Congenital pseudarthrosis of the ulna: a report of two cases and a review of the literature. J Pediatr Orthop 1985;5:463-7.
13. Haddad RJ, Drez D. Salvage procedure: radioulnar fusion for defects in forearm bones. J Bone and Joint Surg 1974;56A: 1097. 14. Kitano K, Tada K. One-bone forearm procedure for partial defect of the ulna. J Pediatr Orthop 1985;5:290-3. 15. Szabo RM, Thorson EP, Raskind JR. Allograft replacement with distal radioulnar joint fusion and ulnar osteotomy for treatment of giant cell tumors of the distal radius. J Hand Surg 1990;15A:929-33. 16. Haque IU. The production of a one-bone forearm as a salvage procedure after hematogenous osteomyelitis. J Bone Joint Surg 1982;64B:454-5. 17. Gustillo RB, Anderson JT. Prevention of infection in the treatment of one thousand and twenty-five open fractures of long bones: retrospective and prospective analysis. J Bone Joint Surg 1978;58A:453-8. 18. Papineau LJ. L'excision-greffe avec fermenture retardee deliberee dans l'osteomyelite chronique. Nouv Presse Med 1973;2:2753-5. 19. Dell P, Sheppard JE. Vascularized bone grafts in the treatment of infected forearm non-unions. J Hand Surg 1984;9A:653-8. 20. Morrey BF, Askew LJ, An KN, Chao EY. A biomechanical study of normal functional elbow motion. J Bone Joint Surg 1981;63A:872-7. 21. Wood MB. Upper extremity reconstruction by vascularized bone transfers: results and complications. J Hand Surg 1987;12A:422-7. 22. Weiland AJ, Kleinert HE, Kutz JE, Daniel RK. Free vascularized bone grafts in surgery of the upper extremity. J Hand Surg 1979;4:129--44.
Forearm instability in the setting of structural bone defects presents a unique reconstructive challenge. Trauma, congenital deformity, or prior surgery may result in symptomatic angular, axial, or torsional radioulnar instability. Such laxity implies incompetence of radial or ulnar diaphyseal architecture, the interosseous soft-tissues, and/or the proximal or distal radioulnar joints and their associated ligamentous complexes. Unstable segmental forearm bone defects or chronic nonunion may be complicated by tissue disruption or sepsis, neurologic compromise, and wrist
From the Departmentof Orthopedics,MayoClinic,Rochester,MN, the Department of Hand Surgery, KagoshimaCity, Kagoshima, Japan. Received for publicationApril 29, 1994; accepted in revised form Feb. 16, 1995. No benefitsin any formhavebeen receivedor will be receivedfrom a commercialparty related directlyor indirectlyto the subject of this article. Reprintrequests:MichaelB. Wood,MD, Departmentof Orthopedics E-14, MayoClinic,200 First StreetSW, Rochester,MN 55905. and
or elbow dysfunction. For such instability, nonoperative management includes functional bracing or activity modification. C o m m o n surgical options include simple internal fixation and bone-grafting; structural bone-graft or prosthetic segmental-spacer interposition; or osteotomy of the adjacent radius or ulna, followed by shortening and fixation. Despite the reported success of these measures, there are clinical situations where forearm stabilization is most efficaciously achieved through surgical creation of a "one-bone forearm" (OBF) via radioulnar synostosis, as described initially by Hey Groves,' and subsequently by othersY 6 The theory behind this procedure has been outlined by Vitale, in that "the ulna 'makes' the elbow; the radius 'makes' the wrist. ''4 Thus, the procedure attempts to create a single, stable, osseous bridge between the ulnohumeral and radiocarpal joints. However, despite multiple reports, there remains no clear agreement as to the specific indications, operative techniques, position of synostosis, or expected outcome. We report our experience with one-bone forearm conThe Journal of Hand Surgery
609
610 Petersonet al. / One-Bone Forearm struction in a series of patients not considered candidates for other reconstructive procedures, with particular emphasis on these areas. P a t i e n t s a n d Methods Retrospective review of our institution's Patient Registry identified 23 patients who underwent surgical radioulnar synostosis between 1973 and 1991. Two additional patients underwent distal radial resection followed by ulnocarpal fusion. Six patients were excluded due to inadequate follow-up information; four had died from complications of metastatic oncologic disease and two failed to return as requested. All clinical records, operative reports, x-ray films, and a mailed follow-up questionnaire for the remaining cohort were retrospectively analyzed by a single reviewer. Questionnaire data was used only to confirm the findings recorded at most recent clinical follow-up examination. Nineteen patients had complete clinical records. Six of these completed follow-up questionnaires. The cohort included 11 men and 8 women with a mean age at the time of procedure of 28 years (range, 3-64) (Table 1). Four patients were skeletally immature at the time of the procedure. Thirteen cases involved the left forearm. Seventeen patients were right-hand dominant, and the dominant extremity was fused in eight cases. Eight patients were manual laborers prior to treatment, of whom two had work-related injuries under worker's compensation jurisdiction. The mean time from procedure to final clinical review was 42 months (range, 6-145) (Table 1). Patients were grouped by pathologic etiology. Type 1 patients had bony instability secondary to trauma. Type 2 patients had atraumatic instability secondary to prior osseous tumor resection or congenital deformity. Thirteen type 1 and six type 2 (five tumor, one congenital) cases were noted. Primary indications for conversion to a one-bone forearm included significant, symptomatic, angular, axial, or rotatory radioulnar instability in the setting of segmental bone loss or refractory nonunion (Fig. 1). Additionally, 13 patients had failed previous reconstruction attempts. In all cases, rotation-preserving reconstructive options were considered likely to be unsuccessful. Thus, the OBF procedure was used as a salvage technique for these patients. Relative indications included the presence of radiohumeral joint dysfunction or patient choice after discussion of more complex reconstruction alternatives. Ulnohumeral soft-tissue contracture, low-grade degenerative articular change, or wrist dysfunction were not considered routine contraindications.
Figure 1. Radioulnar instability after distal ulnar resection was performed for a deforming, painful osteochondroma.
Bony pathology was isolated to the radius in six patients, to the ulna in four, and both in nine. Fourteen patients (eight type 1, six type 2) had instability secondary to segmental loss (six radial, four ulnar, four both), with a mean gap of 7.7 cm (range, 2-15). Five patients (all type 1) had chronic, refractory nonunion (one radial, one ulnar, three both).
Post-traumatic Instability (Type 1) In the 13 cases with type 1 post-traumatic instability, 11 had previously sustained open fractures: 3 involving the radius alone, 6 involving both radius and ulna, and 2 involving the radius or ulna and the carpus in combination. Using the open-fracture classification of Gustillo and Anderson, ~7 there were three grade II, two grade III A, five grade III B, and one grade III c fractures. Two patients had instability after relatively lesssevere trauma. One suffered a closed distal radius fracture with malunion and distal radioulnar joint (DRUJ) instability; the second fell onto an outstretched hand, which resulted in lunotriquetral ligament tear and DRUJ disruption. Both had symptomatic radioulnar instability after multiple failed bone and soft-tissue reconstruction attempts. Eight of the type 1 patients had a severe associated injury to the brachial plexus, ulnar, radial, or median nerves in the ipsilateral extremity that required primary repair, interposition grafting, neurolysis, or tendon transfers.
Instability After Oncologic Resection or Congenital Deformity (Type 2) Of the five patients with instability after primary bone tumor resection, two had distal radial giant cell tumors, and one respectively had proximal radial grade-1 chondrosarcoma or Ewing's sarcoma. One
The Journal of Hand Surgery/ Vol. 20A No. 4 July 1995 611 patient had instability and a chronically dislocated radial head after resection of the distal ulna for a deforming, painful osteochondroma. The single procedure for congenital deformity involved severe radioulnar bowing with chronic posterolateral radial-head dislocation and loss of motion requiring proximal radius and distal ulnar resection.
Instability With Associated Joint Dysfunction Preoperative elbow abnormality was present in 16 patients. The ulnohumeral joint alone was involved in four, the radiohumeral joint alone in three, and both in nine. All had soft tissue contractures with a mean extension/flexion arc of 30~ ~ and a mean proration/supination arc from neutral of 33o/53 ~ One patient showed early ulnohumeral degenerative change on x-ray films. No patient had gross ligamentous elbow instability. Three had previous radialhead resection, three had proximal-radius resection for tumor, two (previously mentioned) had a chronically dislocated, irreducible radial head, and one had a previous total-elbow arthroplasty that required revision/replantation for infection. Isolated wrist abnormality was present in three patients, and isolated DRUJ abnormality in four. Eight had combined wrist and DRUJ abnormality. Of the 11 patients with wrist abnormality, 8 had severe instability, secondary to bone or tissue loss in 6 and neurogenic weakness in 2. One patient each had previously undergone complete wrist arthrodesis, selected intracarpal fusion, or arthroscopic debridement of a triangular fibrocartilage complex tear. Of those patients with DRUJ abnormality, all had instability. Six had prior distal ulna resection for tumor resection or pain relief. In three others, a similar resection was performed during the OBF procedure.
Surgical Technique Operative technique varied between the five surgeons involved in treating this heterogeneous patient population. Surgical approach, architectural apposition of radius, ulna, and/or carpus, and fixation technique were determined individually based on preoperative bone stock and soft-tissue evaluation. Prior incisions were used if possible. A dorsal approach was used in seven cases, anterior in one, ulnar in five, and combined in six. The location of fusion involved the proximal third of the forearm in three cases, the middle in seven, and the distal third in nine. In 16 cases, the proximal ulna was coapted and fixed to the distal radius after subperiosteal exposure and cortical abrasion (Fig. 2). The remaining three patients underwent resection of the entire distal radius and portions of the carpus for tumor or trauma, requiring simultaneous wrist fusion. Free, vascularized fibula transfer was used in two of these forearms. Both were reconstructed with the fibula spanning from the remaining proximal ulna or radius to the third metacarpal base. In one of these
Prior Surgical Procedures Three patients were referred to our center with incomplete records of previous procedures. For the remaining 16 patients, the mean number of previous reconstructive procedures on the involved extremity was 4 (range, 0-18). Type 1 patients had a mean of seven previous procedures (range, 3-18); type 2 patients had a mean of one (range, 0-2). Ten type 1 patients had a history of deep infection. Seven had culture-positive osteomyelitis, two had deep softtissue abscesses, and one had an infected totalelbow arthroplasty. All had been treated and were thought clinically free of infection at the time of the OBF procedure.
Figure 2. One-bone forearm construct with synostosis of proximal ulna to distal radius in the same patient as Figure 1.
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Table 1.
Patient No./Age (years)
Follow-up (months)
Instability Etiology
Synostosis Pronation (degrees)
25
15
Trauma (Crush injury, segmental radius, soft-tissue loss)
29
63
Tumor (Proximal radial/ chondrosarcoma, s/p resect)
40
Proximal radial resected, F/E, P/S contracture
64
10
Trauma (Infected ulnar N/U, failed ORIF)
40
Radial head resected F/E, P/S contracture
3
6
51
5
Preoperative Elbow~Wrist Pathology F/E, P/S contracture, Wrist unstable
Congenital (ulnar/radial bowing)
0
Radial/head dislocated P/S contractnre
57
Tumor (Recurrent distal radial GCT, s/p wide resection)
0
Wrist instability after resection
19
18
Trauma (Open crush/Galeazzi fracture/DLC, resected distal ulna, osteomyelitis)
0
P/S contracture, wrist instability
23
9
30
F/E contracture
25
121
24
17
Trauma (Radial/ulnar segment defects after I+D post-trauma osteomyelitis)
15
F/E contracture, wrist weakness
10 35
13
Trauma (Crush, DRUJ unstable, multiple reconstruction attempts, infection)
30
F/E, P/S contracture, s/p wrist fusion
11 39
42
Trauma (Colle's malunion, multiple failed reconstruction attempts)
0
Ulnar wrist, DRUJ instability
12 31
17
Tumor (Distal radial GCT, s/p resection w/distal ulna/carpus)
5
F/E, P/S contracture Wrist instability
13 7
120
Trauma (Crush/lacerated radial ulnar defects, osteomyelitis, s/p I+D)
0
F/E, P/S contracture, Carpal resection, s/p soft-tissue arthroplasty
14 42
36
Trauma (Chronic N/U radial/ulna)
0
15 8
8
Tumor (Proximal radial/Ewing's sarcoma, s/p resect)
0
Proximal radial resection, instability
Trauma (Infxn. N/U ulna) Trauma (GSW elbow, s/p infxh TEA, proximal radial loss/unstable)
0
s/p TEA, Elbow F/E, P/S contractures, wrist weakness
16 24
145
Trauma (Segment defect radial/ulna)
0
F/E contracture, wrist instability
17 9
118
Tumor (Distal ulna OC, s/p resection)
0
Radial head dislocation F/E, P/S contracture
18 25
12
Trauma (Carpal instability, failed distal ulna resection)
20
P/S contracture, intracarpal instability and fusions
19/42
13
Trauma (Open fracture elbow, s/p multiple reconstruction attempts)
25
F/E, P/S contracture, proximal radius, distal ulna resection, TFCC tear
P/S, pronation/supination; F/E, flexion/extension; N/U, Nonunion; DRUJ, distal radioulnar joint; TFCC, triangular fibrocartilage complex; GCT, giant cell tumor; TEA, total elbow arthroplasty; OC, osteochondroma; ORIF, open reduction and internal fixation; DLC; dislocation; s/p, status/post; I+D, incision and drainage.
The Journal of Hand Surgery / Vol. 20A No. 4 July 1995
Individual Patient Data
History of Infection
No. Previous Procedures
Union
Complications
Score
No
N/A
Yes
No
2
Yes
Yes
N/A
Yes
4
No
0
Yes
10
No
2
No
Yes
8
Yes
Yes
4
No
Nonunion
Yes
N/A
Yes
Infected TEA
No
Infection (deep), nonunion
Yes
Radius fracture
No
No
Infection (deep), nonunion
No
Yes
Delayed union
Yes
Yes
Infection (deep)
Nonunion
Yes
Yes
18
6 Fixation plate pain
Loose pin, N/U ulnocarpal fusion
6
8 8
Yes
3
No
No
1
Yes
Yes
5
Yes
No
1
Yes
No
5
No*
Nonunion *union after revision ORIF
8
Yes
16
Yes
Hardware failure, recurrent ulnar nerve entrapment
6
7 8
Infection (superficial)
6 8
613
614
Peterson et al. / One-Bone Forearm
two patients the proximal end of the fibular graft was fixated to the proximal ulna; in the second, fibula-toradius fixation was used, requiring simultaneous proximal radioulnar synostosis (Fig. 3). The third patient underwent carpal centralization and fusion to the distal ulna, followed by proximal radioulnar synostosis. The rotational position of the fusion was at neutral in 10 cases. The remaining nine forearms were fused in varying degrees of pronation with a mean of 24 ~ (range, 5~176 Fixation techniques were variable. Nine patients had cortical screw fixation alone, with a mean of 3 screws being used (range, 1-4); four had multiple Kirschner wires (K-wires) alone; two had external fixation with pins through both radius and ulna (one supplemented with K-wires); one had a single Steinman pin; one had a combination of screws and K-wires; and two had a dorsal neutralization plate supplemented with bicortical screws or cerclage wiring. The distal ulna was fully resected during the procedure in three patients, and partially, along with the distal radius, in two. One patient underwent 7 mm of intraoperative ulnar recession to prevent postoperative carpal impingement after radial shortening was noted during synostosis. Fourteen patients had autologous bone grafting at the fusion site. Morselized cancellous graft was used in all; six were supplemented with structural corticocancellous graft. One patient in an external fixator underwent open-technique grafting as described by Papineau/8 Three patients underwent free, vascularized fibular transfer. Two, as noted previously, were placed distal to the synostosis as part of concurrent wrist arthrodesis, and one at the actual synostosis site. Simultaneous procedures at the time of synostosis included wrist arthrodesis in three patients, tendon transfer or lengthening in three, soft tissue flap coverage in two, fibular transfer in three, ulnar neuroly-
sis in one, revision of a fourth metacarpal-hamate fusion in one, and distal ulnar resection or recession, as previously noted. Mean tourniquet time was 133 minutes, and the mean operative time was 254 minutes (range, 70-720). All patients except those with external fixation were protected in a long arm cast for a mean of 9 weeks postoperatively (range, 6-16 weeks), until radiographic and clinical evidence of synostosis consolidation were present. Progressive range-of-motion and strengthening exercises were then begun. Evaluation of Results
Clinical outcome at follow-up evaluation was measured and compared using a 10-point, subjective scoring system designed for this review, based on function, pain, and attainment of union (Table 2). Functional capability was assessed as follows: "near normal" patients reported no significant impairment in their use of the involved forearm. "Complex activity" function included those patients who reported definite impairment in forearm performance but who could still easily perform tasks beyond the "daily activity" level (e.g., manual labor, repetitive motor tasks, lifting more than 20 lbs. repetitively, etc.). "Activities of daily living" function allows patients to perform basic personal hygiene, drive a car, cook, and so on. "Minimal" function describes a forearm useless for most or all activities of daily living. Pain level was subjectively graded by patients in the follow-up questionnaire by choosing between none, mild, moderate, or severe. Union was judged by single-reviewer analysis of serial anteroposterior and lateral x-ray films. Overall outcomes were then graded by total score summation (Table 2).
Results
Figure 3. One-bone forearm construct with free, vascularized fibular transfer and associated "fibulocarpal" fusion.
Results obtained using the above scoring system are given in Table 1. Seven patients were rated as excellent; six, good; five, fair; and one, poor. In type 1 patients, nine had excellent or good results, compared with all six of the type 2 patients. The mean score for type 1 patients was 5.6 (range, 3-8), versus 8.0 (range, 6-10) in type 2 forearms. All patients, regardless of clinical score, were satisfied with their outcomes. Comparative statistical analysis was performed via Wilcoxon's exact test for ordinal variables using clin-
The Journal of Hand Surgery / Vol. 20A No. 4 July 1995
Table 2. Ten-point Scoring System For Clinical Results Category Functional capability
Pain level
Union
Level
Points
Near normal Complex activities Activities of daily living Minimal None Mild Moderate
6 4 2 0 3 2 1
Severe
0
Yes No
1 0
Grading system: 8-10 cumulative points = excellent; 6-7 points = good; 4-5 points = fair; 0-3 points = poor.
ical scores at follow-up evaluation. Factors associated with a poorer result included traumatic primary pathology (type 1 patients), two or more previous major reconstructive procedures, history of a severe nerve injury, and a history of previous infection (p <.05). No significant correlation with outcome was able to be shown for rotational position of fusion, location of fusion, distal ulnar excision, prior soft tissue injury (unless associated with infection), preoperative wrist or elbow abnormality, or postoperative nonunion. Eleven patients were employed prior to injury, and six (four manual laborers) returned to their previous employment, while three (two manual laborers) returned to different, less physically demanding jobs. Thus, only half of manual laborers were able to return to their previous level of employment. Two patients, both under worker's compensation jurisdiction, had not returned to work at the time of the follow-up evaluation. Range of motion and strength testing were not uniformly recorded at the follow-up evaluation. Ten patients had complications related to their synostosis, including nonunion, infection, hardware failure, and fracture. Nine involved post-traumatic cases; therefore, the major complication rate in the type 1 patient group was 69% versus 17% in the type 2 group (p <.05). Six patients (five type 1, one type 2) had nonunion, for an overall rate of 32%. Five of these occurred during the early postoperative course. Only one had sufficient symptoms to warrant revisional bone-grafting and fixation, and then progressed to union. The others, having achieved an increased degree of foreann stability via fibrous union, were effectively man-
615
aged with bracing and activity modification without further surgery. One patient with apparent clinical and radiographic union underwent hardware removal at 3 years. She subsequently developed a painless pseudarthrosis and was braced. Nonoperative management of these five nonunions resulted in good overall function with high patient satisfaction (Table 1). No statistical correlation of rotational position, synostosis location, fixation technique, or postoperative immobilization could be made with the presence of nonunion. Four patients developed three deep and one superficial postoperative infections. These occurred in three of the type 1 patients with a history of open fracture, and all had a history of previous infection. All resolved after debridement and parenteral antibiotic therapy. One patient sustained a radius fracture distal to the synostosis site 2 weeks after surgery while in a long arm cast. It was retrospectively noted that the radial cortex had been saucerized to allow insetting of the ulna during coaptation. We surmise the resultant stress riser led to mechanical failure despite protective immobilization. Union was achieved after internal fixation with a plate and screws. One patient, with preoperative ulnohumeral degenerative change, fractured all three bicortical fixation screws while in a cast (Fig. 4). After revisional fixation, he also progressed uneventfully to union. However, he returned a year later with increased arthritic symptoms and mild elbow instability, and is presently awaiting treatment. Three patients had minor complications. One patient had loosening of Steinman pin fixation and did well following pin reinsertion. One required subcutaneous ulnar plate removal for mechanical symptoms, and one had delayed union requiring functional bracing until union occurred. We were unable to ascertain the presence or degree of postoperative forearm shortening in the patient group. A mean of 1.2 further major reconstructive procedures had been performed on the operated extremity at the time of final follow-up evaluation (range, 0-5).
Discussion In 1921, Hey Groves 1 first described the use of radioulnar synostosis as a salvage procedure for failed bone-grafting of a distal radius nonunion. Using a specially designed lever, the proximal ulnar shaft was impacted into the distal radial metaphysis
616
Peterson et al. / One-Bone Forearm
Figure 4. This fixation failure required revisional internal fixation to attain union.
after distal ulnar resection. Greenwood reported a similar technique in 1932 in a child after radial diaphysectomy for osteomyelitis, yet contended the distal ulna should be spared, rendering the wrist "perhaps more stable and possibly more mobile. ''2 Watson-Jones (1934) returned to distal ulnar resection for cosmesis and length-maintenance, asserting that wrist stability is retained by a bony buttress generated by the remaining ulnar periosteal tube? He was also the first to recommend a rotational position for fusion, that of 10 ~ pronation. Vitale (1952) reported good results in two children for congenital and postresection deformity, the first noted use of the technique for ulnar pathology. 4 In 1955, Murray outlined the use of step-cuts and intramedullary nail or lag-screw cortical fixation in two cases for achieving synostosis? Procedural indications included instability in the setting of pain, weakness, loss of rotation, or "massive bone loss associated with loss of the articulating joint surface. ''5 Lowe (1963) reported good results in seven patients fused in neutral or up to 45 ~ of supination. 6 All patients with documentation of postoperative limb length had shortening, with a mean of 2.3 inches. In the largest series to date, Reid and Baker (1973) reported 90% "good cosmetic and functional results" in 10 procedures with indeterminate follow-up periods. 7 The single failure was due to deep infection requiring debridement. Castle (1974) demonstrated apparently satisfactory long-term results in six cases of post-traumatic or infectious nonunion with accompanying soft-tissue defects using intramedullary-nail fixation. 8 A normal hand with normal radiocarpal and ulnohumeral joints was considered a prerequisite for a good result. Several authors have noted a potential benefit of synostosis versus other forms of reconstruction in the developing pediatric forearm. 4'9 Both proximal and
distal physes of the new forearm bone may be preserved to provide optimal length and growth potential. Most recently, pediatric case reports have noted successful use of radioulnar fusion as a primary or salvage procedure in congenital ulnar pseudarthrosis, either idiopathic or secondary to neurofibromatosis. 9-ll Finally, Dell and Sheppard (1984) have used vas, cularized fibular transfer and external fixation in the setting of infected radius or ulnar nonunion to create a stable one-bone forearm. 19 One of their four cases resulted in nonunion, requiring secondary bone grafting. A summary of the previously published results shown in Table 2 associates the OBF procedure with predictably good results. Limb shortening appears to be the only recurrent complication. However, to date these have been relatively small series, with anecdotal grading of postoperative function and variable follow-up periods. As previously mentioned, issues that remain unclear include surgical indications, the optimum rotational position of synostosis, the impact of associated elbow or wrist pathology, the need for resection of the ulnar head, and the rate of both acceptable outcome and complications. Viewing our results, two different populations become apparent, based on the etiology of forearm instability. Post-traumatic, type 1 patients underwent more previous surgery, had a higher incidence of prior infection, presented with poorer soft tissue and bone stock, and had overall poorer results with a higher complication rate than the type 2, nontrauma group. The greater degree of initial insult to the forearm in these cases may predicate a worse result regardless of reconstruction technique. Nevertheless, 9 of type 1 patients achieved an excellent or good result with synostosis as a salvage procedure, as compared with all patients in the type 2 group. The recommended position of forearm rotation in the literature has generally been one of neutral or
The Journal of Hand Surgery / Vol. 20A No. 4 July 1995
slight pronationY ,8 Morrey et al. 2~have defined the range of pronation supination needed for various daily tasks. Greater pronation is generally required for tasks involving interaction with the external environment, whereas greater supination aids in moving the hand normally about the body. Our results show no superiority of fusion in either neutral or pronation. We have no experience with fusion in supination as previously reported. 6,7 Shoulder rotation and abduction/adduction allow the neutral or pronated forearm to attain pronation, neutral, or even slight supination. Such adaptability may not be the case for the supinated forearm. However, as noted by Reid et al., some laborers may benefit from a position of supination in the nondominant hand to allow grasping of certain tools] Some patients may benefit from preoperative casting or bracing of the forearm in various degrees of rotation, allowing experimentation to determine optimum individual position. Previous reports have regarded preoperative ulnohumeral or wrist pathology as a contraindication to creation of OBE 4'5'8A4 Statistical analysis of our patients' clinical scores did not demonstrate worse results in such a setting. However, based on this patient population, we cannot predict accurately the result of radioulnar synostosis in the setting of severe intra-articular ulnohumeral pathology or instability. Significant radiohumeral dysfunction was a relatively favorable indication for surgery in our patients. Wrist instability was usually addressed at the time of surgery, which appeared to be an effective technique. Ipsilateral wrist fusion did not affect results. Previous authors have debated the question of distal ulnar resection with regard to wrist stability and cosmetic deformity.1-3 In five cases, we partially or fully resected, and in one case shortened, the distal ulna as part of the synostosis procedure. Additionally, the distal ulna had been previously resected in six cases. There was no correlation between excision/shortening and clinical outcome. No patient with distal ulnar retention complained of carpal impingement symptoms or cosmetic deformity postoperatively The high complication rate in these patients is disconcerting. As nearly all (90%) major complications occurred in the type 1, post-traumatic instability group, this may reflect the general severity of injury and the level of reconstructive challenge in these patients. Notably, all four cases of postoperative infection occurred in patients with a history of sepsis. Certainly the principles of adequate local tissue management--including prompt, aggressive debridement, antibiotic therapy, flap coverage of large
617
defects, staged reconstruction, and delayed closure of tenuous wounds--must be applied. The 32% rate of nonunion is higher than previously reported, ~9 and underscores the need for rigid fixation, aggressive bone grafting, and adequate postoperative immobilization after optimal soft-tissue control has been achieved. Interestingly, nonunion did not necessarily correlate with poor clinical results. The mean score for this group was 6.3, with two good, one fair, and one poor ranking, indicating a high degree of function with minimal or no pain. The relatively small size of our study population may limit statistical correlation of nonunion with functional outcome. Alternately, sufficient fibrous union may have been achieved in these forearms to limit pain and allow reasonable function despite lack of bony union. Radioulnar synostosis, or the creation of a onebone forearm, remains a useful technique for managing angular, axial, or rotatory radioulnar instability in the setting of significant or refractory osseous defects. Indications include a likelihood of failure of rotation-preserving techniques, failure of previous such methods, inability to perform resource-intensive procedures such as vascularized bone transfer 2~ or osteogenic bone transport if appropriate, or desire for a single, relatively simple procedure to regain a functional forearm lever. Preoperative radiohumeral joint dysfunction appears a favorable indication. Active infection or poor soft-tissue condition requires definitive management prior to synostosis. Pre-existing wrist dysfunction does not appear to affect outcome. Although no definite conclusions can be drawn from our data on whether significant intra-articular ulnohumeral pathology or instability are contraindications, we advise caution in this setting. The optimal rotational position of the forearm synostosis remains unclear. Preoperative trial bracing may be useful to allow informed patient choice regarding position. Rigid fixation and autologous bone graft should be used, and the extremity should be protected until clinical and radiographic evidence of union are present. Excision of the distal ulnar fragment appears not to affect the functional outcome. A subjective scoring system is presented to allow comparison of results. Severe trauma, a history of infection or severe nerve injury, and multiple previous procedures are associated with poorer results. Such patients have higher rates of postoperative complications, including nonunion, than previously reported, but still may be successfully salvaged by this technique.
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Peterson et al. / One-Bone Forearm
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