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Ulnar shortening using the AO small distractor
Ulnar Shortening Using the AO Small Distractor Marwan A. Wehb~, MD, Bryn Mawr, PA, David A. Cautilli, MD, Philadelphia, PA Twenty-four patients (24 wrists) with ulnar impaction syndrome underwent ulnar shortening osteotomy. They were reviewed retrospectively to evaluate a technique using the AO small distractor and 2.7-mm dynamic compression plate. A transverse osteotomy using an external compres:sion device and compression plating was performed in all cases. The average followup time was 32 months. Clinical and radiographic union occurred at an average of 9.7 weeks. There were no nonunions. This study demonstrates that ulnar transverse shortening osteotomy with external compression and plating is a simple and effective method of ulnar shortening, and that highly precise and complex instrumentation is not essential. (J Hand Surg 1995;20A:959-964.)
Decompression of the ulnocarpal articulation by ulnar shortening is the mainstay of treatment of the ulnar impaction syndrome. The ulnar impaction or ulnocarpal loading syndrome has been described by several authors. 1~ In 1941 Milch 5 described his technique in a patient who had a fracture of the distal radius. He resected a variable amount of ulnar diaphysis and internally fixed it with wire suture. Since Milch's original description, there have been many modifications, particularly with AO-ASIF rigid internal fixation methods. 2,8-1~These include use of transverse, oblique, and step-cut osteotomies. This article presents a new technique of ulnar shortening, using a transverse osteotomy, temporary intraoperative external fixation with the AO small distractor, and internal fixation with a 2.7 mm dynamic compression plate (DCP).
From the Pennsylvania Hand Center, Bryn Mawr, PA, and the Department of Orthopaedic Surgery, Jefferson Medical College, Philadelphia, PA. Received for publication Oct. 14, 1993; accepted in revised form May 19, 1995. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Marwan A. Wehb6, MD, Pennsylvania Hand Center, Reprints Department, RO. Box 241, Bryn Mawr, PA 19010.
Materials and Methods Twenty-four wrists in 24 patients were treated by the technique. Preoperative ulnar variance was an average of 1 mm (range, -2-+8 mm). There were 12 men and 12 women, whose ages ranged from 18 to 67 years (average, 38 years). The average follow-up interval from time of osteotomy was 32 months (range, 8-74 months); one patient was lost to followup evaluation 8 months after surgery. Clinical and x-ray film evaluations were performed both before and after surgery. All surgical procedures and examinations were performed by the senior author. Results were graded based on pain, range of motion, and function as proposed by Darrow et al. 2 (Table 1). Time to bony union of the osteotomy was recorded in all patients. Clinical union of the osteotomy was judged by painless range of wrist and forearm motion and lack of tenderness at the osteotomy site. Radiographic union was judged by obliteration of the osteotomy line, or with bony trabeculae clearly crossing the osteotomy site.
Operative Procedure The distal ulna is approached through a skin incision over its subcutaneous border and exposed extraperiosteally. Care is taken to protect the dorsal sen-
The Journal of Hand Surgery
959
960 Wehb6 and Cautilli / Ulnar Shortening Table 1. Criteria for Grading Results of Ulnar Shortening Osteotomy Grade
Criteria
Excellent
Full range of motion No pain No functional limitation
Good
Mild decrease in range of motion Mild discomfort with use Mild functional limitation
Fair
Moderate decrease in range of motion Moderate discomfort with use Function limiting full return to work
Poor
Severe decrease in range of motion Persistent pain Function limiting return to gainful employment Nonunion
Data from Darrow et al.2 sory branch of the ulnar nerve. A six-hole (8 cases) or seven-hole (16 cases), 2.7 mm AO DCP is held over the exposed ulna to determine the level of the osteotomy; this is planned in the area of the plate without a screw hole. That area is marked by scoring the periosteum with a scalpel. The periosteum is not stripped beyond the osteotomy site. Next, an AO small distractor (No. 394.06, Synthes [USA], Paoli, PA) is placed across the proposed osteotomy site, at a right angle to the site of plate application. The distractor-external fixator can be either palmar or dorsal to the plate location. Threaded 2.5-mm Kirschner wires are inserted in the inner two holes, and 0.062-inch Kirschner wires in the outer two holes to control rotation (Fig. 1A). The fixator is then pushed down to bone and its nuts are tightened around the half pins. Two transverse osteotomies are performed with an oscillating saw to obtain the desired length of ulnar shortening (Figs. 1B, 2). One case in this series had an oblique osteotomy with interfragmentary lag screw fixation. A wafer of bone is removed and external compression is applied across the osteotomy site by turning the central dial of the small distractor (Fig. 1C, D). Some care should be taken to note whether any displacement does occur at the osteotomy site while compression is being applied. A 2.7-mm DCP is applied and centered across the osteotomy site. T h e first four screws are placed eccentrically, two on each side of the osteotomy site (Fig. 1E). The small distractor is then removed and the screws are tightened further to complete the dynamic compression. The half-pins are then removed. The remaining screws may also be placed eccentrically for additional compression of the
osteotomy site (Fig. IF). Additional surgery, such as triangular fibrocartilage resection or ligament reconstruction, is done as needed. After surgery, patients are immediately placed in a plaster sugartong splint. Sutures are removed 3 days after surgery and the wound is steri-stripped at that time. Immobilization is continued full-time for 2 to 4 weeks after surgery, at which time wrist flexion and extension are started with part-time splinting. Pronation and supination exercises are initiated at the earliest sign of either clinical or bony union, from 6 to 8 weeks after surgery (Fig. 3). Forearm rotation is started sooner if there is confidence in the internal fixation at the time of surgery (Table 2). Plates were removed in all but two patients in this series at an average of 16 months after surgery (range, 8-44 months). At that time, patients were given a removable sugartong splint to wear for activity only for 8 more weeks. One patient, who was followed for 63 months, had no problem with the plate; another patient was lost to follow-up evaluation at 8 months.
Results Follow-up data were obtained on all patients, and all examinations were performed by the senior author. The length of the follow-up interval ranged from 4 to 74 months, with an average of 30 months.
~)
(B)
~
__l= 0D)
(gj
Figure 1. The ulnar shortening technique.
--
0'
The Journal of Hand Surgery / Vo[. 20A No. 6 November 1995
Figure 2. Intraoperative photograph of external fixator in place as ulnar osteotomy is completed.
961
All but one patient reported complete relief of ulnar wrist pain; the latter had significant, but not complete, relief of symptoms. The results, as judged by the criteria in Table 1, were excellent in 17, good in 6, and fair in 1. The one patient with a fair result had a healed osteotomy by 9 weeks after surgery but continued to have pain, which was relieved with a radioulnar joint resection. Clinical union of the osteotomy occurred at an average of 9 weeks (range, 6-12 weeks); this interval excluded three patients with delayed union. Radiographic union occurred at an average of 8.8 weeks (range, 6-12 weeks); the amount of callus present was scant in all cases. There were three delayed unions by our criteria; they all healed uneventfully at 28, 34, and 36 weeks with complete relief of pain. Using less restrictive criteria, such as bony trabeculae crossing the osteotomy site, these were healed at 12, 16, and 20 weeks, respectively. Thus, the average time to union would be 9.7 weeks.
Figure 3. (A) X-ray film of wrist 5 days after ulnar shortening. Note the ulnar styloid fracture and loose body in the ulnar pouch; these remained asymptomatic. (B) Five weeks after surgery, early bony union is evident. There is no tenderness at the osteotomy site, and range of motion is painless. (Figure continues.)
962
Wehb6 and Cautilli / Ulnar Shortening
of 1 mm positive (range, - 2 - + 8 mm) for the entire group, and postoperative variance was an average of -2.3 nun (range, 0 - 4 mm).
Discussion The concept of ulnocarpal impaction is not new, nor is ulnar shortening. Milch devised a "cuff resection" of the distal ulna with wire suture fixation for the treatment of post-traumatic radial shortening? Since then many surgical procedures have been performed for the treatment of ulnar impaction syndrome. These include the Darrach procedure, 11 hemiresection-interposition technique, 12 matched arthroplasty, 13 the ulnar wafer procedure, 14 arthroscopic partial ulnar head excision, and various types of ulnar shortening procedures. Modern AO-ASIF rigid internal fixation techniques 9 have allowed improvements in Milch's original ulnar shortening method. 2,8 These include transverse, oblique, and step-cut ulnar diaphyseal osteotomies internally fixed with AO compressing plating. 1 However, reports of long-term follow-up examinations of different ulnar shortening osteotomies are few. Darrow et al. 2 reported on the use of a transverse osteotomy and compression plate fixation for ulnar shortening. They reported an average union of 13 weeks, with one nonunion. Rayhack et al. '5 reported on a comparison of transverse and oblique ulnar osteotomy both using an intricate cutting guide and compression plating system. They reported an average time to union of 20.6 weeks and one nonunion with the transverse osteotomy and average union at 11.4 weeks with the oblique osteotomy. Comparison of these results with our own is shown in Table 3. Comparison of healing times for straight and oblique osteotomies is not the purpose of this study. An oblique osteotomy with interfragmentary screw fixation was, however, used on a few cases not included in this study and did not improve the healing time to any degree. In fact, the only case so treated that was included in this study went on to a delayed union.
Figure 3. (Continued) (C) X-ray film obtained 14 months after ulnar shortening shows complete bone remodeling.
There were no nonunions. One patient fell after plate removal and fractured her ulna through the osteotomy line; it was replated and healed uneventfully, with complete relief of symptoms. The use of six- or seven-hole plates for internal fixation did not correlate with time to union or postoperative result. Pain directly over the plate occurred in 13 patients, yet there was some tenderness in the area of the plate in all patients. For this reason all plates were removed at an average of 16 months after surgery (range, 8 4 4 months). The average ulnar shortening was 3 m m (range, 1-9 mm). Preoperative ulnar variance was an average
Table 2. Time Until Initiation of Range of Motion (weeks)
Before Postoperative Week Wrist (no. of patients) Forearm (no. of patients)
1
2
3
4
5
6
7
8
>8
4 2
5 1
l -
3 3
-
4 5
2 3
1 2
4 8
The Journal of Hand Surgery / Vol. 20A No. 6 November 1995
963
Table 3. Comparison of Ulnar Shortening Techniques
Study
Osteotomy
Number of Cases
Range of motion started (weeks)
Union (weeks)
Nonunion (no. of cases)
Darrow et al. .2 Rayhack et al. *~5
Transverse Transverse Oblique Transverse
35 23 17 24
> 13 6 6 Wrist 2 Forearm 6
13 21 11 9.7
1 1 0 0
Wehb6 et al.
*Subperiosteal plating.
It is difficult to define bony union. An osteotomy is usually healed when there is clear evidence of callus formation. The osteotomy line can remain visible, however, during the early stages of bony union (Fig. 3). For this reason, clinical criteria, such as tendemess at the osteotomy site and painless range of motion, should be taken into consideration when determining bony union. These factors are not detailed in any of the studies reviewed. Using less restrictive criteria such as Rayhack's 15(bony trabeculae crossing the osteotomy site), our cases would have been considered healed even sooner. The results presented in this study are superior to the results of other transverse osteotomies and comparable to those of the oblique osteotomy with regard to time to union. Several factors in our technique may be responsible for this. First, the soft tissue dissection is kept extraperiosteal to preserve the blood supply to the ulna for healing. Only a couple of millimeters of periosteum are stripped at the osteotomy site prior to cutting the bone, Second the external compression device allows preliminary compression and fixation across the osteotomy site, allowing ease of application of the compression plate. This should lead to rapid union of the osteotomy through primary bone healing? Bone grafting was not used, because it would increase the morbidity of surgery; one could theorize that it might have averted the three delayed unions. The AO 2.7mm DCP was not designed for use specifically on the ulna. Its use here did not result in any plate failures, even in the patient who took 36 weeks to heal. This device may cause less pain over the plate as opposed to the 3.5-ram DCP, and it did not prolong healing time. But even this smaller plate required removal because its superficial location resulted in pain in half of the patients and localized tenderness in all. Additional benefits of this technique are that the external device maintains angular and rotational align-
ment of the proximal and distal osteotomy fragments. It is also commercially available, inexpensive, and simple to apply. We feel that the compression obtained is similar to that of an oblique osteotomy with lag screw fixation. However, the transverse osteotomy is easier to perform without use of intricate cutting guides. This technique is a simple and effective treatment for ulnar impacfion syndrome and compares favorably with other ulnar shortening techniques. It attests that exacting techniques and complex instrumentation are not necessary for ulnar shortening.
References 1. Bowers WH. The distal radioulnar joint. In: Green DP, ed. Operative hand surg. New York: Churchill Livingstone, 1982:743-69. 2. Darrow JC, Linscheid RL, Dobyns JH, Mann JM, Wood MB, Beckenbaugh RD. Distal ulnar recession for disorders for the distal radioulnar joint. J Hand Surg 1985;10A: 482-91. 3. Friedman SL, Palmer AK. The ulnar impaction syndrome. Hand Clin 1991;7:295-310. 4. Palmer AK, Linscheid RL, Fisk GR, Taleisnik J. Symposium: distal ulnar injuries. Contemp Orthop 1983; 7:81-120. 5. Milch H. Cuff resection of the ulna for malunited Colles' fracture. J Bone Joint Surg 1941;23:311-3. 6. Palmer AK, Werner FW. The triangular fibrocartilage complex of the wrist: anatomy and function. J Hand Surg 1981;6:153-61. 7. Richards RR, Bowen VA. Recessional ulnar osteotomy: use of reduction forceps for intraoperative radiography and plate application. J Hand Surg 1993;18A:56-7. 8. Chun S, Palmer AK. The ulnar impaction syndrome: follow-up of ulnar shortening osteotomy. J Hand Surg 1993;18A:46-53. 9. Mtiller ME, Alg6wer M, Schneider R, Willengger H. Manual of internal fixation: techniques recommended by the AOGroup, 2nd ed. Berlin: Springer-Verlag, 1979:192-3. 10. Boulas JH, Milek MA. Ulnar shortening for tears of the triangular fibrocartilaginous complex. J Hand Surg 1990; 15A:415-20.
964
Wehb~ and Cautilli / Ulnar Shortening
11. Dingman PVC. Resection of the distal end of the ulna (Darrach operation): an end result study of 24 cases. J Bone Joint Surg 1952;34A:893-900. 12. Bowers WH. Distal radioulnar joint arthroplasty: the hemiresection-interposition technique. J Hand Surg 1985; 10A:169-78. 13. Watson HK, Ryu J, Burgess RC. Matched distal ulnar resection. J Hand Surg 1986;11A:812-7.
14. Feldon P, Terrono AL, Belsky MR. Wafer distal ulnar resection for posttraumatic disorders of the distal radioulnar joint. J Hand Surg 1992;17A:731-7. 15. Rayhack JM, Gasser SI, Latta LL, Ouellette EA, Milne EL. Precision oblique osteotomy for shortening of the ulna. J Hand Surg 1993;18A:908-18.
Decompression of the ulnocarpal articulation by ulnar shortening is the mainstay of treatment of the ulnar impaction syndrome. The ulnar impaction or ulnocarpal loading syndrome has been described by several authors. 1~ In 1941 Milch 5 described his technique in a patient who had a fracture of the distal radius. He resected a variable amount of ulnar diaphysis and internally fixed it with wire suture. Since Milch's original description, there have been many modifications, particularly with AO-ASIF rigid internal fixation methods. 2,8-1~These include use of transverse, oblique, and step-cut osteotomies. This article presents a new technique of ulnar shortening, using a transverse osteotomy, temporary intraoperative external fixation with the AO small distractor, and internal fixation with a 2.7 mm dynamic compression plate (DCP).
From the Pennsylvania Hand Center, Bryn Mawr, PA, and the Department of Orthopaedic Surgery, Jefferson Medical College, Philadelphia, PA. Received for publication Oct. 14, 1993; accepted in revised form May 19, 1995. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Marwan A. Wehb6, MD, Pennsylvania Hand Center, Reprints Department, RO. Box 241, Bryn Mawr, PA 19010.
Materials and Methods Twenty-four wrists in 24 patients were treated by the technique. Preoperative ulnar variance was an average of 1 mm (range, -2-+8 mm). There were 12 men and 12 women, whose ages ranged from 18 to 67 years (average, 38 years). The average follow-up interval from time of osteotomy was 32 months (range, 8-74 months); one patient was lost to followup evaluation 8 months after surgery. Clinical and x-ray film evaluations were performed both before and after surgery. All surgical procedures and examinations were performed by the senior author. Results were graded based on pain, range of motion, and function as proposed by Darrow et al. 2 (Table 1). Time to bony union of the osteotomy was recorded in all patients. Clinical union of the osteotomy was judged by painless range of wrist and forearm motion and lack of tenderness at the osteotomy site. Radiographic union was judged by obliteration of the osteotomy line, or with bony trabeculae clearly crossing the osteotomy site.
Operative Procedure The distal ulna is approached through a skin incision over its subcutaneous border and exposed extraperiosteally. Care is taken to protect the dorsal sen-
The Journal of Hand Surgery
959
960 Wehb6 and Cautilli / Ulnar Shortening Table 1. Criteria for Grading Results of Ulnar Shortening Osteotomy Grade
Criteria
Excellent
Full range of motion No pain No functional limitation
Good
Mild decrease in range of motion Mild discomfort with use Mild functional limitation
Fair
Moderate decrease in range of motion Moderate discomfort with use Function limiting full return to work
Poor
Severe decrease in range of motion Persistent pain Function limiting return to gainful employment Nonunion
Data from Darrow et al.2 sory branch of the ulnar nerve. A six-hole (8 cases) or seven-hole (16 cases), 2.7 mm AO DCP is held over the exposed ulna to determine the level of the osteotomy; this is planned in the area of the plate without a screw hole. That area is marked by scoring the periosteum with a scalpel. The periosteum is not stripped beyond the osteotomy site. Next, an AO small distractor (No. 394.06, Synthes [USA], Paoli, PA) is placed across the proposed osteotomy site, at a right angle to the site of plate application. The distractor-external fixator can be either palmar or dorsal to the plate location. Threaded 2.5-mm Kirschner wires are inserted in the inner two holes, and 0.062-inch Kirschner wires in the outer two holes to control rotation (Fig. 1A). The fixator is then pushed down to bone and its nuts are tightened around the half pins. Two transverse osteotomies are performed with an oscillating saw to obtain the desired length of ulnar shortening (Figs. 1B, 2). One case in this series had an oblique osteotomy with interfragmentary lag screw fixation. A wafer of bone is removed and external compression is applied across the osteotomy site by turning the central dial of the small distractor (Fig. 1C, D). Some care should be taken to note whether any displacement does occur at the osteotomy site while compression is being applied. A 2.7-mm DCP is applied and centered across the osteotomy site. T h e first four screws are placed eccentrically, two on each side of the osteotomy site (Fig. 1E). The small distractor is then removed and the screws are tightened further to complete the dynamic compression. The half-pins are then removed. The remaining screws may also be placed eccentrically for additional compression of the
osteotomy site (Fig. IF). Additional surgery, such as triangular fibrocartilage resection or ligament reconstruction, is done as needed. After surgery, patients are immediately placed in a plaster sugartong splint. Sutures are removed 3 days after surgery and the wound is steri-stripped at that time. Immobilization is continued full-time for 2 to 4 weeks after surgery, at which time wrist flexion and extension are started with part-time splinting. Pronation and supination exercises are initiated at the earliest sign of either clinical or bony union, from 6 to 8 weeks after surgery (Fig. 3). Forearm rotation is started sooner if there is confidence in the internal fixation at the time of surgery (Table 2). Plates were removed in all but two patients in this series at an average of 16 months after surgery (range, 8-44 months). At that time, patients were given a removable sugartong splint to wear for activity only for 8 more weeks. One patient, who was followed for 63 months, had no problem with the plate; another patient was lost to follow-up evaluation at 8 months.
Results Follow-up data were obtained on all patients, and all examinations were performed by the senior author. The length of the follow-up interval ranged from 4 to 74 months, with an average of 30 months.
~)
(B)
~
__l= 0D)
(gj
Figure 1. The ulnar shortening technique.
--
0'
The Journal of Hand Surgery / Vo[. 20A No. 6 November 1995
Figure 2. Intraoperative photograph of external fixator in place as ulnar osteotomy is completed.
961
All but one patient reported complete relief of ulnar wrist pain; the latter had significant, but not complete, relief of symptoms. The results, as judged by the criteria in Table 1, were excellent in 17, good in 6, and fair in 1. The one patient with a fair result had a healed osteotomy by 9 weeks after surgery but continued to have pain, which was relieved with a radioulnar joint resection. Clinical union of the osteotomy occurred at an average of 9 weeks (range, 6-12 weeks); this interval excluded three patients with delayed union. Radiographic union occurred at an average of 8.8 weeks (range, 6-12 weeks); the amount of callus present was scant in all cases. There were three delayed unions by our criteria; they all healed uneventfully at 28, 34, and 36 weeks with complete relief of pain. Using less restrictive criteria, such as bony trabeculae crossing the osteotomy site, these were healed at 12, 16, and 20 weeks, respectively. Thus, the average time to union would be 9.7 weeks.
Figure 3. (A) X-ray film of wrist 5 days after ulnar shortening. Note the ulnar styloid fracture and loose body in the ulnar pouch; these remained asymptomatic. (B) Five weeks after surgery, early bony union is evident. There is no tenderness at the osteotomy site, and range of motion is painless. (Figure continues.)
962
Wehb6 and Cautilli / Ulnar Shortening
of 1 mm positive (range, - 2 - + 8 mm) for the entire group, and postoperative variance was an average of -2.3 nun (range, 0 - 4 mm).
Discussion The concept of ulnocarpal impaction is not new, nor is ulnar shortening. Milch devised a "cuff resection" of the distal ulna with wire suture fixation for the treatment of post-traumatic radial shortening? Since then many surgical procedures have been performed for the treatment of ulnar impaction syndrome. These include the Darrach procedure, 11 hemiresection-interposition technique, 12 matched arthroplasty, 13 the ulnar wafer procedure, 14 arthroscopic partial ulnar head excision, and various types of ulnar shortening procedures. Modern AO-ASIF rigid internal fixation techniques 9 have allowed improvements in Milch's original ulnar shortening method. 2,8 These include transverse, oblique, and step-cut ulnar diaphyseal osteotomies internally fixed with AO compressing plating. 1 However, reports of long-term follow-up examinations of different ulnar shortening osteotomies are few. Darrow et al. 2 reported on the use of a transverse osteotomy and compression plate fixation for ulnar shortening. They reported an average union of 13 weeks, with one nonunion. Rayhack et al. '5 reported on a comparison of transverse and oblique ulnar osteotomy both using an intricate cutting guide and compression plating system. They reported an average time to union of 20.6 weeks and one nonunion with the transverse osteotomy and average union at 11.4 weeks with the oblique osteotomy. Comparison of these results with our own is shown in Table 3. Comparison of healing times for straight and oblique osteotomies is not the purpose of this study. An oblique osteotomy with interfragmentary screw fixation was, however, used on a few cases not included in this study and did not improve the healing time to any degree. In fact, the only case so treated that was included in this study went on to a delayed union.
Figure 3. (Continued) (C) X-ray film obtained 14 months after ulnar shortening shows complete bone remodeling.
There were no nonunions. One patient fell after plate removal and fractured her ulna through the osteotomy line; it was replated and healed uneventfully, with complete relief of symptoms. The use of six- or seven-hole plates for internal fixation did not correlate with time to union or postoperative result. Pain directly over the plate occurred in 13 patients, yet there was some tenderness in the area of the plate in all patients. For this reason all plates were removed at an average of 16 months after surgery (range, 8 4 4 months). The average ulnar shortening was 3 m m (range, 1-9 mm). Preoperative ulnar variance was an average
Table 2. Time Until Initiation of Range of Motion (weeks)
Before Postoperative Week Wrist (no. of patients) Forearm (no. of patients)
1
2
3
4
5
6
7
8
>8
4 2
5 1
l -
3 3
-
4 5
2 3
1 2
4 8
The Journal of Hand Surgery / Vol. 20A No. 6 November 1995
963
Table 3. Comparison of Ulnar Shortening Techniques
Study
Osteotomy
Number of Cases
Range of motion started (weeks)
Union (weeks)
Nonunion (no. of cases)
Darrow et al. .2 Rayhack et al. *~5
Transverse Transverse Oblique Transverse
35 23 17 24
> 13 6 6 Wrist 2 Forearm 6
13 21 11 9.7
1 1 0 0
Wehb6 et al.
*Subperiosteal plating.
It is difficult to define bony union. An osteotomy is usually healed when there is clear evidence of callus formation. The osteotomy line can remain visible, however, during the early stages of bony union (Fig. 3). For this reason, clinical criteria, such as tendemess at the osteotomy site and painless range of motion, should be taken into consideration when determining bony union. These factors are not detailed in any of the studies reviewed. Using less restrictive criteria such as Rayhack's 15(bony trabeculae crossing the osteotomy site), our cases would have been considered healed even sooner. The results presented in this study are superior to the results of other transverse osteotomies and comparable to those of the oblique osteotomy with regard to time to union. Several factors in our technique may be responsible for this. First, the soft tissue dissection is kept extraperiosteal to preserve the blood supply to the ulna for healing. Only a couple of millimeters of periosteum are stripped at the osteotomy site prior to cutting the bone, Second the external compression device allows preliminary compression and fixation across the osteotomy site, allowing ease of application of the compression plate. This should lead to rapid union of the osteotomy through primary bone healing? Bone grafting was not used, because it would increase the morbidity of surgery; one could theorize that it might have averted the three delayed unions. The AO 2.7mm DCP was not designed for use specifically on the ulna. Its use here did not result in any plate failures, even in the patient who took 36 weeks to heal. This device may cause less pain over the plate as opposed to the 3.5-ram DCP, and it did not prolong healing time. But even this smaller plate required removal because its superficial location resulted in pain in half of the patients and localized tenderness in all. Additional benefits of this technique are that the external device maintains angular and rotational align-
ment of the proximal and distal osteotomy fragments. It is also commercially available, inexpensive, and simple to apply. We feel that the compression obtained is similar to that of an oblique osteotomy with lag screw fixation. However, the transverse osteotomy is easier to perform without use of intricate cutting guides. This technique is a simple and effective treatment for ulnar impacfion syndrome and compares favorably with other ulnar shortening techniques. It attests that exacting techniques and complex instrumentation are not necessary for ulnar shortening.
References 1. Bowers WH. The distal radioulnar joint. In: Green DP, ed. Operative hand surg. New York: Churchill Livingstone, 1982:743-69. 2. Darrow JC, Linscheid RL, Dobyns JH, Mann JM, Wood MB, Beckenbaugh RD. Distal ulnar recession for disorders for the distal radioulnar joint. J Hand Surg 1985;10A: 482-91. 3. Friedman SL, Palmer AK. The ulnar impaction syndrome. Hand Clin 1991;7:295-310. 4. Palmer AK, Linscheid RL, Fisk GR, Taleisnik J. Symposium: distal ulnar injuries. Contemp Orthop 1983; 7:81-120. 5. Milch H. Cuff resection of the ulna for malunited Colles' fracture. J Bone Joint Surg 1941;23:311-3. 6. Palmer AK, Werner FW. The triangular fibrocartilage complex of the wrist: anatomy and function. J Hand Surg 1981;6:153-61. 7. Richards RR, Bowen VA. Recessional ulnar osteotomy: use of reduction forceps for intraoperative radiography and plate application. J Hand Surg 1993;18A:56-7. 8. Chun S, Palmer AK. The ulnar impaction syndrome: follow-up of ulnar shortening osteotomy. J Hand Surg 1993;18A:46-53. 9. Mtiller ME, Alg6wer M, Schneider R, Willengger H. Manual of internal fixation: techniques recommended by the AOGroup, 2nd ed. Berlin: Springer-Verlag, 1979:192-3. 10. Boulas JH, Milek MA. Ulnar shortening for tears of the triangular fibrocartilaginous complex. J Hand Surg 1990; 15A:415-20.
964
Wehb~ and Cautilli / Ulnar Shortening
11. Dingman PVC. Resection of the distal end of the ulna (Darrach operation): an end result study of 24 cases. J Bone Joint Surg 1952;34A:893-900. 12. Bowers WH. Distal radioulnar joint arthroplasty: the hemiresection-interposition technique. J Hand Surg 1985; 10A:169-78. 13. Watson HK, Ryu J, Burgess RC. Matched distal ulnar resection. J Hand Surg 1986;11A:812-7.
14. Feldon P, Terrono AL, Belsky MR. Wafer distal ulnar resection for posttraumatic disorders of the distal radioulnar joint. J Hand Surg 1992;17A:731-7. 15. Rayhack JM, Gasser SI, Latta LL, Ouellette EA, Milne EL. Precision oblique osteotomy for shortening of the ulna. J Hand Surg 1993;18A:908-18.