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Acromial insufficiency in reverse shoulder arthroplasties
J Shoulder Elbow Surg (2009) 18, 495-502
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Acromial insufficiency in reverse shoulder arthroplasties Gilles Walch, MDa,*, Franck Mottier, MDb, Bryan Wall, MDc, Pascal Boileau, MDd, Daniel Mole´, MDe, Luc Favard, MDf a
Centre Orthope´dique Santy, 24 Avenue Paul Santy, F-69008 Lyon, France Hoˆpital d’Instruction des Arme´es Desgenettes, 108 Bd Pinel, F-69003 Lyon, France c LSU Health Sciences Center, 200 West Esplanade Ave, Kenner, LA d Hoˆpital de L’Archet, 151 Rte St Antoine Ginestie`re, F-06000 Nice, France e Clinique de Traumatologie, 49 rue Hermite, F-54000 Nancy, France f Hoˆpital Trousseau, CHRU de Tours, F-37044 Tours, cedex 9, France b
Hypothesis: Reverse shoulder prostheses depend on deltoid function. An injury to the acromion, either fracture or meso-acromion, or deltoid injury, may affect the outcomes of patients after receiving a reverse shoulder prosthesis. Methods: Four-hundred and fifty-seven consecutive reverse shoulder prostheses were implanted between January 1992 and June 2003 by one of seven surgeons in five separate centers. Forty-one patients were noted to have a pre-operative lesion of the acromion or scapular spine. Twenty-three presented with an os acromiale (meso-acromion). Seventeen had fracture or fragmentation of the acromion. One patient had a pseudarthrosis of the scapular spine. Results: Preoperative acromial pathology, surgical approach, and amount of inferior acromial tilt did not diminished postoperative range of motion, Constant score, or subjective results when compared to patients without acromial pathology. In contrast, the four patients with postoperative acromial spine fractures had inferior results with respect to functional and subjective results. Conclusion: Preoperative acromial lesions are not a contraindication to reverse shoulder arthroplasty. Postoperative fracture of the acromial spine has a significant effect on results and treatment is uncertain. Level of evidence: Level 3; Therapeutic retrospective case control study. Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees.
Glenohumeral arthritis associated with massive rotator cuff tears had been referred to by numerous descriptions prior to 1983, when Charles Neer coined the term cuff tear arthropathy (CTA).13 This served to consolidate different
*Reprint requests: Gilles Walch, MD, Centre orthope´dique Santy, 24 avenue Paul Santy. E-mail address: [email protected] (G. Walch).
previously described anatomic and radiographic characteristics, including glenohumeral arthritis, humeral head superior migration, and massive cuff tears. In 1990, Hamada described a radiographic classification of massive rotator cuff repairs divided into 5 stages.8 Stage I has minimal radiographic changes. In stage II, there is narrowing of the subacromial space to 5 mm or less. Stage III is defined by erosion and acetabulization of the acromion secondary to superior migration of the humeral head. Stage
1058-2746/2009/$36.00 - see front matter Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees. doi:10.1016/j.jse.2008.12.002
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Figure 1 Preoperative nonunion of the scapular spine on the AP view with 30 tilt of the acromion (A) and on the axial plan of MRI (B). Two years postoperative, there is a 50 tilt of the acromion (C) that does not prevent correct painless active elevation (D).
IV is associated with glenohumeral arthritis and has been subdivided into stage IVA (without acetabulization) and stage IVB (with acetabulization).16 Stage V indicates the onset of humeral head osteonecrosis. The acetabulization of the shoulder can have a spectrum of effects on the acromion. The bone may be simply thinned, or fatigue fracture or fragmentation of the entire acromion may be present. The acromial insertion of the deltoid is a key element in the function of the reverse prosthesis: the lowering and medialization of the glenohumeral center of rotation in order to restore deltoid tension is critical to restore active elevation.6,1 Preoperative acromial pathology could theoretically compromise deltoid function and affect the ability of the prosthesis to function properly. With the increasing utilization of reverse shoulder
arthroplasty (RSA), the wisdom of using this type of prosthesis in a patient whose acromion has been eroded by the superior migration of the humeral head has been questioned. The goal of the present study is to examine the incidence of pre- and postoperative lesions of the acromion and scapular spine and to analyze their influence on the results of surgery.
Materials and methods Between January 1992 and June 2003, 457 reverse prostheses were implanted in 430 patients (27 bilateral cases) at 5 French centers specializing in shoulder surgery. All reverse prostheses
Acromial insufficiency in reverse shoulder arthroplasties
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Figure 2 Preoperative Os acromiale (meso-acromion). A, AP view showing a tilt of 30 ; B, saggital view; C, saggital plan on MRI; D, postoperative tilt of 70 on AP view ; E, tilt on saggital view.
implanted were included, and all patients were contacted for follow-up at a minimum of 2 years postoperatively. There were 77.5% females and 22.5% males. The mean age was 72.3 years. Two-hundred and eighty-three prostheses were implanted in patients with no history of prior shoulder surgery. Seventy prostheses were implanted after at least 1 failed surgery, excluding arthroplasty. One-hundred and four prostheses were placed for the revision of a prior hemiarthroplasty or total shoulder arthroplasty. From this group, 41 patients were identified with preoperative acromial pathology. All patients were evaluated pre- and postoperatively with active and passive range of motion, Constant score, and standardized radiographs.2 In addition, patients were asked to grade their subjective level satisfaction with their outcome as very satisfied, satisfied, uncertain, or disappointed. The pre- and postoperative radiographic series was comprised of an anteriorposterior (AP) view of the glenohumeral joint in neutral, internal, and external rotation, in addition to an axillary view. Preoperatively, 60% of cases had a CT arthrogram, 32% had either a MRI or MR arthrogram, and 8% had no additional studies. Preoperative acromial pathology was identified in 9.0% of all cases in this series. One patient (0.2%) had a nonunion of a preoperative stress fracture of the scapular spine (Figure 1). Twenty-three patients (5.0%) presented with a meso-acromion variant of os acromiale (Figure 2).3,10,11 Seventeen (3.7%) patients presented with an acquired lesion of the acromion, with 10 having
a fatigue fracture of the acromion (Figure 3) and 7 having fragmentation (Figure 4). The average age of patients in this group was 74.3. There were 35 females and 6 males. The dominant extremity was involved in 92.7% of the cases. A deltopectoral approach was used in twentynine cases (70.7%), and a superolateral approach was used in 12 cases (29.3%). The operative technique was not adjusted because of the presence of the acromial pathology. The deltoid was tensioned such that there was no pistoning between the humeral and glenoid components at the end of the intervention. In patients operated on via the superolateral approach, osteosynthesis was performed in 1 patient with an os acromial and 2 others underwent excision of an acromial fragment or os acromial (1 each). The underlying pathology leading to RSA was CTA (Hamada stage IV or V) in 28 cases, massive cuff tear without glenohumeral arthritis (Hamada stages I-II-III) in 10 cases, and revision of hemiarthroplasty in 3 cases. When divided by Hamada stage, there were 11 cases in stage V, 17 cases in stage IVB, 8 cases in stage III, and 2 cases in stage II. The 3 cases of revision hemiarthroplasty were not classifiable according to the Hamada stage. All patients, except for the 2 in the Hamada stage II group, had acromio-humeral contact preoperatively. Inferior tilt of the lateral fragment of the acromion was estimated on the pre- and postoperative AP radiograph. This estimation was done using the angle between the scapular spine and the displaced
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Figure 3 Acquired lesions of the acromion: fatigue fracture of the acromion. A, Preoperative AP view; B, saggital; C, axial plan of CT scan showing the stress fracture of the acromion; D, immediate postoperative and 5-year FU AP views showing the same tilt of 85 . acromial fragment. Preoperatively, 32 shoulders (17 os acromial, 14 fracture-fragmentation, 1 spine nonunion) showed no evidence of acromial tilt, whereas 9 shoulders (6 os acromial, 3 fracture-fragmentation) displayed an average of 43.3 tilt. Postoperatively, a simple sling was placed for a period of 1 month. Passive range of motion was begun immediately. Active motion was delayed until the beginning of the second postoperative month. Statistical analysis was performed using the nonparametric Mann Whitney U test and Wilcoxon rank sum test. Qualitative values were compares using the Chi-square analysis of Fisher’s exact test. For all comparisons, P value <.05 was considered significant. Analysis was performed using StatViewâ (Abacus Concepts Inc., Berkely, CA) and R (R Foundation for Statistical Computing, 2005). This study did not undergo Institutional Review Board approval.
Results The 41 patients with identified acromial pathology were reviewed at an average 40 months postoperatively (range, 24-100). Table I summarizes the pre- and postoperative Constant scores, mobility, and subjective results according to the type of preoperative acromial pathology. There was no difference between groups with respect to Constant score (P ¼ .63), active elevation (P ¼ .92), and subjective satisfaction. The average Constant score was higher for patients with os acromial (68.3) than for patients with fracture-fragmentation of the acromion (56.7), yet this difference was not statistically significant (P ¼ .34). The same was true for average active elevation at 141.8 and 128.7 , respectively (P ¼ .66). There was no significant
Acromial insufficiency in reverse shoulder arthroplasties
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Figure 4 Aquired fragmentation of the acromion. A, AP view; B, sagital view; C, postoperative AP view showing 85 tilt without clinical incidence.
Table I
Clinical results of patients presenting with a pathologic acromion compared to normals Os acromiale 23 cases
Acquired acromial lesions (Fracture or fragmentation) 17 cases
Scapular spine nonunion 1 case
Preop 23 Postop 23 Preop 17 Postop 17 Preop 1 cases cases cases cases cases Constant Score (100 26.8 points) Pain (15 points) 4.3 Activity (20 points) 6.3 Mobility (40 points) 15.2 Strength (25 points) 1.0 Active Elevation 72.2 (degrees) Subjective Results
Postop fracture of scapular spine 4 cases
No acromial pathology
Postop 1 Preop 4 cases cases
Postop 4 Preop 416 Postop 287 cases cases cases
68.3
19.0
56.7
32.0
55.0
20.0
35.0
22.3
57.5
13.1 16.7 29.8 7.9 141
2.8 5.2 10.3 0.9 55.9
11.4 15.6 24.1 5.5 128.7
5.0 5.0 18.0 4.0 90
13.0 18.0 22.0 2.0 130
2.3 3.5 9.8 4.5 57.5
6.8 10.5 15.5 2.3 81.3
3.5 5.6 12.0 1.3 68.3
12.1 15.1 24.3 6.3 123.8
VS 12 S9 U2 D0
VS 12 S5 U2 D0
VS 0 S1 U0 D0
VS 0 S2 U1 D1
VS 203 S 139 U 28 D5
VS, very satisfied; S, satisfied; U, uncertain; D, disappointed.
difference between mean Constant score (P ¼ .54) and active elevation (P ¼ .55) for those cases with acromial fracture-fragmentation and those without. Patients with os acromiale had a statistically superior mean Constant score when compared to normals (68.3 vs 57.5, P ¼ .05). A significant difference was also found for the activity (P ¼ .03) and mobility (P ¼ .02) portions of the Constant score, but there was no difference for pain (P ¼ .24), strength (P ¼ .26), active elevation (P ¼ .17), or subjective satisfaction. With the numbers available, there was not a statistically significant difference in the final results when patients were divided according to acromial pathology and Hamada stage (Table II). The implantation of the reverse prosthesis resulted in an inferior acromial tilt on AP radiographs in 20 of 32 cases in
which there was no preoperative tilt. When a tilt was already present, worsening was seen in 7 out of 9 cases (4 os acromiale and 3 fracture-fragmentation). When patients were grouped according to the presence or absence of tilt, no difference was seen in mean Constant score or active elevation (Table III). There was no difference between the different surgical centers with respect to incidence of acromial pathology or functional outcomes (Table IV). The type of surgical approach did not influence the Constant score (P ¼ .85), active elevation (P ¼ .14), or subjective results (P ¼ .40). The deltopectoral approach did result in increased average inferior acromial tilt (39.5 vs 16.2 , P ¼ .03). The results for the 2 cases in which the acromial lesion was excised are similar to the other cases but are not amenable to statistical
500 Table II
G. Walch et al. Functional results by acromial pathology and etiology of RSA
Meso-acromion Acromial fragmentation Acromial stress fracture Preoperative spine fracture Postoperative spine fracture Constant Score Active elevation
Hamada II 2 cases
Hamada III 8 cases
Hamada IVB 17 cases
Hamada V 11 cases
Revision 3 cases
1 1 0 0 0 71 160
4 2 2 0 0 57.3 128
9 2 5 1 0 62.3 135
7 2 3 0 1 63.5 139
2 0 1 0 1 48.3 104
evaluation. One case of os acromiale underwent operative fixation using a tension band. In spite of developing a nonunion with a persistent 45 , acromial tilt the patient was very satisfied, and the final Constant score was 66 and active elevation was 110 . Four patients out of the 457 (0.8%) in the original group sustained a postoperative fracture of the scapular spine (Figure 5). The first occurred in a patient operated on for a failed hemiarthroplasty, with pain and stiffness. The spine fracture was discovered on the 3-month postoperative radiographs. The patient refused surgical management and was treated conservatively. At 3-years follow-up, a nonunion was still present and the functional outcome was poor (Constant score ¼ 15). Active elevation was only 45 . The subjective result was graded as ‘‘disappointed’’ by the patient. The second case was also diagnosed at the 3-month follow-up visit: the patient originally presented with CTA (stage IVB) and was operated on using a deltopectoral approach (Figure 5). At 2-year follow-up, the fracture had united with 40 of angulation and acromio-humeral impingement. The Constant score was 38 points, and the patient could actively elevate to 110 ; the subjective result was ‘‘satisfied’’. The third case occurred in a patient who had had a previous coracoid transfer for anterior instability that was complicated by a massive cuff tear and superior migration of the humeral head. Progressive degradation of active motion and Constant score was noted 1 year after the intervention. A review of the radiographs revealed a nondisplaced scapular spine fracture that was missed on the first reading. Two-year examination showed the entire acromion to be angulated 55 and the Constant score to be 44 with only 90 of active elevation. The patient was disappointed with the final result, largely secondary to persistent pain. Finally, there was a fourth fracture that occurred in a patient who underwent RSA using a deltopectoral approach for CTA (Hamada V). The fracture was discovered 10 months postoperatively after the patient sustained a fall. Osteosynthesis was attempted using a tension band but failed, and hardware removal was eventually required. There was a residual 25 inferior acromial tilt and a persistent nonunion. The final Constant score was only 43 points due to the dissatisfaction of the patient with the results. The patient declined further intervention.
Table III Effects of inferior acromial tilt on Constant score and active elevation
Constant Score Active elevation
No tilt 18 cases
Tilt 29 cases
Normal acromion 287 cases
55.2 119
62.47 138
57.5 124
All 4 of the postoperative fractures of the scapular spine were discovered within the first year after the surgical intervention. Three of the 4 did not have any history of trauma. RSA was secondary to CTA in 2 cases, revision hemiarthroplasty in 1, and a failed coracoid transfer with a massive cuff tear in 1. The mean Constant score for these 4 cases was 35 points and mean active elevation was only 81 . Postoperative lesions of the scapular spine had significantly worse results than patients with acromial fracturefragmentation, os acromiale, or without acromial pathology. The average Constant score was significantly less than all other patients with acromial pathology (P ¼ .02). The same held true when this group was compared with those free of acromial lesions (P ¼ .04). Active elevation and subjective results were significantly worse than others with acromial pathology (P ¼ .007).
Discussion The surprisingly good results of our patients with preoperative acquired or congenital acromial pathology confirm the good results already reported by Mottier.12 Given the importance of the deltoid, any condition compromising the acromion and deltoid insertion is of legitimate concern for any patient contemplating RSA. There are 3 potential explanations for this surprising results. First, the main part of the deltoid is still attached firmly to the spine of the scapula and clavicle and is obviously strong enough to compensate for the middle part. Second, the less satisfactory Constant score and active forward elevation observed in the global series could be explained by the number of patients with fracture sequaela, post-traumatic arthritis, or revision arthroplasty, which are known to have less
Acromial insufficiency in reverse shoulder arthroplasties Table IV
Center 1 Center 2 Center 3 Center 4 Center 5 Total
501
Distribution of types of acromial pathology by surgical center Os acromiale
Acromial fragmentation
Acromial fracture
Preop scapular spine fracture
Postop scapular spine fracture
Number of cases
0 9 6 3 4 23
O 1 2 2 2 7
0 4 5 1 0 10
0 1 0 0 0 1
0 2 1 1 0 4
9 225 86 79 58 457
satisfactory results.17 Third, it has been shown by Favard and Nyffeler4,14 that the scapulothoracic motion is more important that the glenohumeral one with Reverse shoulder prosthesis. The scapulothoracic motion is not altered by an eventual abutment between the acromion and the greater tuberosity, and could explain that the patients with a severe tilt have the same range of motion that the patient without acromial tilt. In our series of 457 reverse prostheses, 23 (5.0%) presented with an os acromiale. Os acromiale is a congenital anomaly found in 1-15% of the general population, which was comparable to the frequency found in our series.10,11 Some authors have recommended aggressive surgical treatment for these lesions.9 Osteosynthesis of the free fragment when performing RSA would theoretically conserve the deltoid insertion and allow better arm elevation. Osteosynthesis would seem to be difficult in the face of significant lengthening of the deltoid and tension across the deltoid insertion. Additionally, the good results obtained without osteosynthesis lead us to question the utility of this approach. The poor results obtained by Rittmeister and the open reduction internal fixation of an os acromiale performed in our studies group support this position.15 Fracture-fragmentation present in 17 cases (3.7%) appear to be acquired secondary to contact between the humeral head and acromion. This lesion is represented by acromial acetabulization previously described by Neer in his description of CTA, and Hamada noted it in stage III of his classification. In the current series, we have found it in 4 of 8 stage III patients and 8 of 17 stage IVB patients. The acquired lesions of the acromion (fracture or fragmentation) were frequently displaced by the increased tension of the deltoid, but there was no statistically significant effect on postoperative Constant score, active elevation, or subjective result. Postoperative acromial complications after RSA have been described previously in the literature. Rittmeister et al reported 3 cases of reoperations for nonunion of the acromion.15 These cases were all patients with rheumatoid arthritis and utilized a trans-acromial approach with a sagittal osteotomy.7 Werner et al reported 4 cases of acromial or scapular spine fracture in 58 patients.18 Two cases underwent a second procedure, but no details are given regarding the preoperative status of the acromion or type of postoperative fracture. In a series of 60 cases, Frankle et al noted 1 case of
Figure 5
Postoperative fracture of the scapular spine.
scapular spine fracture that occurred 3 months postoperatively and healed spontaneously.5 Two additional cases of acromial fracture were discovered 1 year after the original interventions. One case healed spontaneously and the other required operative fixation. These cases reported by Frankle are similar to the 4 postoperative fractures of the scapular spine that we observed. For all cases, the preoperative acromion was normal and immediate postoperative radiographs showed no sign of fracture. Postoperative fractures of the scapular spine had the worst results in terms of Constant score, active elevation, and subjective satisfaction of all groups. This rare complication (0.8% of our series) should be suspected whenever rehabilitation progresses slowly, is painful, or suddenly deteriorates within the first year. It would be difficult to suggest that the 4 cases we observed were secondary to excessive deltoid tension because weak
502 and osteopenic bone was common to most of the elderly female patients in this series, and the surgical technique was the same for all. The surgical approach cannot be implicated, as we observed the same frequency using the deltopectoral and superolateral approaches. Taking into account the mediocre results obtained and the difficulty of stabilizing an osteoporotic bone under the increased tension of an elongated deltoid, it would seem reasonable to recommend immediate operative fixation using a plate and screw construct associated with postoperative immobilization on a 60 abduction splint in order to avoid nonunion and acromio-humeral contact secondary to inferior acromial tilt. The reported results of Werner and Frankle question the effectiveness of attempted internal fixation.18 Our failed attempt at osteosynthesis also does not allow us to comment on the effectiveness of this technique. At the moment, we recommend a conservative treatment with an abduction splint for 6 weeks to limit pain and acromial tilt, but can not comment on results yet. This study indicates that both acquired and congenital preoperative lesions of the acromion are not a contraindication to RSA. The results obtained are not different from patients with normal acromia. Postoperative fractures of the scapular spine have poor results and early treatment is recommended as soon as they are diagnosed.
Acknowledgments Several of the authors of this paper have disclosed that they receive royalties from Tornier for the reverse prosthesis studied in this paper.
References 1. Boileau P, Watkinson DJ, Hatzidakis AM, Balg F. Grammont reverse prosthesis: Design, rationale and biomechanics. J Shoulder Elbow Surg 2005;14:147S-61S. 2. Constant CR, Murley AHG. A clinical method of functional assessment of the shoulder. Clin Orthop 1987;214:160-4.
G. Walch et al. 3. Edelson JG, Zuckerman J, Hershkovitz I. Os acromiale: anatomy and surgical implications. J Bone Joint Surg Br 1993;75:551-5. 4. Favard L,Guery J, Bicknell Rbacle G, Berhouet J. A radiokinematic study of the Grammont reverse shoulder prosthesis in reverse shoulder arthroplasty. In: Walch G, Boileau P, Mole´ D, Favard L, Le´vigne Ch, Sirveaux F, editors. Montpellier, France: SAURAMPS Medical, 2006. p. 57-68. 5. Frankle M, Siegal S, Pupello D, Saleem A, Mighell M, Vasey M. The reverse shoulder prosthesis for gleno-humeral arthritis associated with reverse rotator cuff deficiency. A minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am 2005;87:1697-705. 6. Grammont PM, Baulot E. Delta shoulder prosthesis for rotator cuff rupture. Orthopaedics 1993;16:65-8. 7. Grammont P, Trouilloud P, Laffay JP, Deries X. Etude et re´alisation d’une nouvelle prothe`se d’e´paule. Rhumatologie 1997;39:17-22. 8. Hamada K, Fukuda H, Mikasa M, Kobayashi Y. Roentgenographic findings in massive totator cuff tears a long term observation. Clin Orthop 1990;254:92-6. 9. Hertel R, Windisch W, Schuster A, Ballmer FT. Transacromial approach to obtain fusion of unstable os acromiale. J Shoulder Elbow Surg 1998;7:606-9. 10. Lee DH, Lee KH, Lopez-Ben R, Bradley EL. The double-density sign: a radiographic finding suggestive of an os acromiale. J Bone Joint Surg Am 2004;86:2666-70. 11. Liberson F. Os acromiale e A contested anomaly. J Bone Joint Surg Br 1937;19:683-9. 12. Mottier F, Wall B, Nove´ Josserand L, Galoisy Guibal L, Walch G. L’acromion pathologique dans les prothe`ses inverse´es d’e´paule: a` propos d’une se´rie de 240 cas. Revue de Chirurgie Orthope´dique 2007;93:133. 13. Neer CSII, Craig EV, Fukuda H. Cuff tear arthropathy. J Bone Joint Surg Am 1983;65:1232-44. 14. Nyffeler RW, Bourgeois A, Farron A. Alteration of the shoulder rhythm after implantation of a reverse total shoulder prosthesis. SECEC Congress 2006, Athens, Conference proceedings. p. 178. 15. Rittmeister M, Kersch-Baumer F. Grammont reverse total shoulder arthroplasty in patients with rheumatoid arthritis and non reconstructible rotator cuff lesions. J Shoulder Elbow Surg 2001;10:17-22. 16. Walch G, Edwards TB, Boulahia A, Nove´-Josserand L, Neyton L, Szabo I. Arthroscopic tenotomy of the long head of the biceps in the treatment of rotator cuff tears: clinical and radiographic results of 307 cases. J Shoulder Elbow Surg 2005;14:238-46. 17. Wall B, Walch G, Nove´-Josserand, Edwards TB. Reverse total shoulder arthroplasty: a review of results according to etiology. J Bone Joint Surg (am) 2007;89:1476-85. 18. Werner CML, Steinmann PA, Gilbart M. Gerber C. Treatment of painful pseudoparesis due to irreparable rotator cuff dysfunction with the Delta III reverse-ball and socket total shoulder prosthesis. J Bone Joint Surg Am 2005;87:1476-86.
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Acromial insufficiency in reverse shoulder arthroplasties Gilles Walch, MDa,*, Franck Mottier, MDb, Bryan Wall, MDc, Pascal Boileau, MDd, Daniel Mole´, MDe, Luc Favard, MDf a
Centre Orthope´dique Santy, 24 Avenue Paul Santy, F-69008 Lyon, France Hoˆpital d’Instruction des Arme´es Desgenettes, 108 Bd Pinel, F-69003 Lyon, France c LSU Health Sciences Center, 200 West Esplanade Ave, Kenner, LA d Hoˆpital de L’Archet, 151 Rte St Antoine Ginestie`re, F-06000 Nice, France e Clinique de Traumatologie, 49 rue Hermite, F-54000 Nancy, France f Hoˆpital Trousseau, CHRU de Tours, F-37044 Tours, cedex 9, France b
Hypothesis: Reverse shoulder prostheses depend on deltoid function. An injury to the acromion, either fracture or meso-acromion, or deltoid injury, may affect the outcomes of patients after receiving a reverse shoulder prosthesis. Methods: Four-hundred and fifty-seven consecutive reverse shoulder prostheses were implanted between January 1992 and June 2003 by one of seven surgeons in five separate centers. Forty-one patients were noted to have a pre-operative lesion of the acromion or scapular spine. Twenty-three presented with an os acromiale (meso-acromion). Seventeen had fracture or fragmentation of the acromion. One patient had a pseudarthrosis of the scapular spine. Results: Preoperative acromial pathology, surgical approach, and amount of inferior acromial tilt did not diminished postoperative range of motion, Constant score, or subjective results when compared to patients without acromial pathology. In contrast, the four patients with postoperative acromial spine fractures had inferior results with respect to functional and subjective results. Conclusion: Preoperative acromial lesions are not a contraindication to reverse shoulder arthroplasty. Postoperative fracture of the acromial spine has a significant effect on results and treatment is uncertain. Level of evidence: Level 3; Therapeutic retrospective case control study. Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees.
Glenohumeral arthritis associated with massive rotator cuff tears had been referred to by numerous descriptions prior to 1983, when Charles Neer coined the term cuff tear arthropathy (CTA).13 This served to consolidate different
*Reprint requests: Gilles Walch, MD, Centre orthope´dique Santy, 24 avenue Paul Santy. E-mail address: [email protected] (G. Walch).
previously described anatomic and radiographic characteristics, including glenohumeral arthritis, humeral head superior migration, and massive cuff tears. In 1990, Hamada described a radiographic classification of massive rotator cuff repairs divided into 5 stages.8 Stage I has minimal radiographic changes. In stage II, there is narrowing of the subacromial space to 5 mm or less. Stage III is defined by erosion and acetabulization of the acromion secondary to superior migration of the humeral head. Stage
1058-2746/2009/$36.00 - see front matter Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees. doi:10.1016/j.jse.2008.12.002
496
G. Walch et al.
Figure 1 Preoperative nonunion of the scapular spine on the AP view with 30 tilt of the acromion (A) and on the axial plan of MRI (B). Two years postoperative, there is a 50 tilt of the acromion (C) that does not prevent correct painless active elevation (D).
IV is associated with glenohumeral arthritis and has been subdivided into stage IVA (without acetabulization) and stage IVB (with acetabulization).16 Stage V indicates the onset of humeral head osteonecrosis. The acetabulization of the shoulder can have a spectrum of effects on the acromion. The bone may be simply thinned, or fatigue fracture or fragmentation of the entire acromion may be present. The acromial insertion of the deltoid is a key element in the function of the reverse prosthesis: the lowering and medialization of the glenohumeral center of rotation in order to restore deltoid tension is critical to restore active elevation.6,1 Preoperative acromial pathology could theoretically compromise deltoid function and affect the ability of the prosthesis to function properly. With the increasing utilization of reverse shoulder
arthroplasty (RSA), the wisdom of using this type of prosthesis in a patient whose acromion has been eroded by the superior migration of the humeral head has been questioned. The goal of the present study is to examine the incidence of pre- and postoperative lesions of the acromion and scapular spine and to analyze their influence on the results of surgery.
Materials and methods Between January 1992 and June 2003, 457 reverse prostheses were implanted in 430 patients (27 bilateral cases) at 5 French centers specializing in shoulder surgery. All reverse prostheses
Acromial insufficiency in reverse shoulder arthroplasties
497
Figure 2 Preoperative Os acromiale (meso-acromion). A, AP view showing a tilt of 30 ; B, saggital view; C, saggital plan on MRI; D, postoperative tilt of 70 on AP view ; E, tilt on saggital view.
implanted were included, and all patients were contacted for follow-up at a minimum of 2 years postoperatively. There were 77.5% females and 22.5% males. The mean age was 72.3 years. Two-hundred and eighty-three prostheses were implanted in patients with no history of prior shoulder surgery. Seventy prostheses were implanted after at least 1 failed surgery, excluding arthroplasty. One-hundred and four prostheses were placed for the revision of a prior hemiarthroplasty or total shoulder arthroplasty. From this group, 41 patients were identified with preoperative acromial pathology. All patients were evaluated pre- and postoperatively with active and passive range of motion, Constant score, and standardized radiographs.2 In addition, patients were asked to grade their subjective level satisfaction with their outcome as very satisfied, satisfied, uncertain, or disappointed. The pre- and postoperative radiographic series was comprised of an anteriorposterior (AP) view of the glenohumeral joint in neutral, internal, and external rotation, in addition to an axillary view. Preoperatively, 60% of cases had a CT arthrogram, 32% had either a MRI or MR arthrogram, and 8% had no additional studies. Preoperative acromial pathology was identified in 9.0% of all cases in this series. One patient (0.2%) had a nonunion of a preoperative stress fracture of the scapular spine (Figure 1). Twenty-three patients (5.0%) presented with a meso-acromion variant of os acromiale (Figure 2).3,10,11 Seventeen (3.7%) patients presented with an acquired lesion of the acromion, with 10 having
a fatigue fracture of the acromion (Figure 3) and 7 having fragmentation (Figure 4). The average age of patients in this group was 74.3. There were 35 females and 6 males. The dominant extremity was involved in 92.7% of the cases. A deltopectoral approach was used in twentynine cases (70.7%), and a superolateral approach was used in 12 cases (29.3%). The operative technique was not adjusted because of the presence of the acromial pathology. The deltoid was tensioned such that there was no pistoning between the humeral and glenoid components at the end of the intervention. In patients operated on via the superolateral approach, osteosynthesis was performed in 1 patient with an os acromial and 2 others underwent excision of an acromial fragment or os acromial (1 each). The underlying pathology leading to RSA was CTA (Hamada stage IV or V) in 28 cases, massive cuff tear without glenohumeral arthritis (Hamada stages I-II-III) in 10 cases, and revision of hemiarthroplasty in 3 cases. When divided by Hamada stage, there were 11 cases in stage V, 17 cases in stage IVB, 8 cases in stage III, and 2 cases in stage II. The 3 cases of revision hemiarthroplasty were not classifiable according to the Hamada stage. All patients, except for the 2 in the Hamada stage II group, had acromio-humeral contact preoperatively. Inferior tilt of the lateral fragment of the acromion was estimated on the pre- and postoperative AP radiograph. This estimation was done using the angle between the scapular spine and the displaced
498
G. Walch et al.
Figure 3 Acquired lesions of the acromion: fatigue fracture of the acromion. A, Preoperative AP view; B, saggital; C, axial plan of CT scan showing the stress fracture of the acromion; D, immediate postoperative and 5-year FU AP views showing the same tilt of 85 . acromial fragment. Preoperatively, 32 shoulders (17 os acromial, 14 fracture-fragmentation, 1 spine nonunion) showed no evidence of acromial tilt, whereas 9 shoulders (6 os acromial, 3 fracture-fragmentation) displayed an average of 43.3 tilt. Postoperatively, a simple sling was placed for a period of 1 month. Passive range of motion was begun immediately. Active motion was delayed until the beginning of the second postoperative month. Statistical analysis was performed using the nonparametric Mann Whitney U test and Wilcoxon rank sum test. Qualitative values were compares using the Chi-square analysis of Fisher’s exact test. For all comparisons, P value <.05 was considered significant. Analysis was performed using StatViewâ (Abacus Concepts Inc., Berkely, CA) and R (R Foundation for Statistical Computing, 2005). This study did not undergo Institutional Review Board approval.
Results The 41 patients with identified acromial pathology were reviewed at an average 40 months postoperatively (range, 24-100). Table I summarizes the pre- and postoperative Constant scores, mobility, and subjective results according to the type of preoperative acromial pathology. There was no difference between groups with respect to Constant score (P ¼ .63), active elevation (P ¼ .92), and subjective satisfaction. The average Constant score was higher for patients with os acromial (68.3) than for patients with fracture-fragmentation of the acromion (56.7), yet this difference was not statistically significant (P ¼ .34). The same was true for average active elevation at 141.8 and 128.7 , respectively (P ¼ .66). There was no significant
Acromial insufficiency in reverse shoulder arthroplasties
499
Figure 4 Aquired fragmentation of the acromion. A, AP view; B, sagital view; C, postoperative AP view showing 85 tilt without clinical incidence.
Table I
Clinical results of patients presenting with a pathologic acromion compared to normals Os acromiale 23 cases
Acquired acromial lesions (Fracture or fragmentation) 17 cases
Scapular spine nonunion 1 case
Preop 23 Postop 23 Preop 17 Postop 17 Preop 1 cases cases cases cases cases Constant Score (100 26.8 points) Pain (15 points) 4.3 Activity (20 points) 6.3 Mobility (40 points) 15.2 Strength (25 points) 1.0 Active Elevation 72.2 (degrees) Subjective Results
Postop fracture of scapular spine 4 cases
No acromial pathology
Postop 1 Preop 4 cases cases
Postop 4 Preop 416 Postop 287 cases cases cases
68.3
19.0
56.7
32.0
55.0
20.0
35.0
22.3
57.5
13.1 16.7 29.8 7.9 141
2.8 5.2 10.3 0.9 55.9
11.4 15.6 24.1 5.5 128.7
5.0 5.0 18.0 4.0 90
13.0 18.0 22.0 2.0 130
2.3 3.5 9.8 4.5 57.5
6.8 10.5 15.5 2.3 81.3
3.5 5.6 12.0 1.3 68.3
12.1 15.1 24.3 6.3 123.8
VS 12 S9 U2 D0
VS 12 S5 U2 D0
VS 0 S1 U0 D0
VS 0 S2 U1 D1
VS 203 S 139 U 28 D5
VS, very satisfied; S, satisfied; U, uncertain; D, disappointed.
difference between mean Constant score (P ¼ .54) and active elevation (P ¼ .55) for those cases with acromial fracture-fragmentation and those without. Patients with os acromiale had a statistically superior mean Constant score when compared to normals (68.3 vs 57.5, P ¼ .05). A significant difference was also found for the activity (P ¼ .03) and mobility (P ¼ .02) portions of the Constant score, but there was no difference for pain (P ¼ .24), strength (P ¼ .26), active elevation (P ¼ .17), or subjective satisfaction. With the numbers available, there was not a statistically significant difference in the final results when patients were divided according to acromial pathology and Hamada stage (Table II). The implantation of the reverse prosthesis resulted in an inferior acromial tilt on AP radiographs in 20 of 32 cases in
which there was no preoperative tilt. When a tilt was already present, worsening was seen in 7 out of 9 cases (4 os acromiale and 3 fracture-fragmentation). When patients were grouped according to the presence or absence of tilt, no difference was seen in mean Constant score or active elevation (Table III). There was no difference between the different surgical centers with respect to incidence of acromial pathology or functional outcomes (Table IV). The type of surgical approach did not influence the Constant score (P ¼ .85), active elevation (P ¼ .14), or subjective results (P ¼ .40). The deltopectoral approach did result in increased average inferior acromial tilt (39.5 vs 16.2 , P ¼ .03). The results for the 2 cases in which the acromial lesion was excised are similar to the other cases but are not amenable to statistical
500 Table II
G. Walch et al. Functional results by acromial pathology and etiology of RSA
Meso-acromion Acromial fragmentation Acromial stress fracture Preoperative spine fracture Postoperative spine fracture Constant Score Active elevation
Hamada II 2 cases
Hamada III 8 cases
Hamada IVB 17 cases
Hamada V 11 cases
Revision 3 cases
1 1 0 0 0 71 160
4 2 2 0 0 57.3 128
9 2 5 1 0 62.3 135
7 2 3 0 1 63.5 139
2 0 1 0 1 48.3 104
evaluation. One case of os acromiale underwent operative fixation using a tension band. In spite of developing a nonunion with a persistent 45 , acromial tilt the patient was very satisfied, and the final Constant score was 66 and active elevation was 110 . Four patients out of the 457 (0.8%) in the original group sustained a postoperative fracture of the scapular spine (Figure 5). The first occurred in a patient operated on for a failed hemiarthroplasty, with pain and stiffness. The spine fracture was discovered on the 3-month postoperative radiographs. The patient refused surgical management and was treated conservatively. At 3-years follow-up, a nonunion was still present and the functional outcome was poor (Constant score ¼ 15). Active elevation was only 45 . The subjective result was graded as ‘‘disappointed’’ by the patient. The second case was also diagnosed at the 3-month follow-up visit: the patient originally presented with CTA (stage IVB) and was operated on using a deltopectoral approach (Figure 5). At 2-year follow-up, the fracture had united with 40 of angulation and acromio-humeral impingement. The Constant score was 38 points, and the patient could actively elevate to 110 ; the subjective result was ‘‘satisfied’’. The third case occurred in a patient who had had a previous coracoid transfer for anterior instability that was complicated by a massive cuff tear and superior migration of the humeral head. Progressive degradation of active motion and Constant score was noted 1 year after the intervention. A review of the radiographs revealed a nondisplaced scapular spine fracture that was missed on the first reading. Two-year examination showed the entire acromion to be angulated 55 and the Constant score to be 44 with only 90 of active elevation. The patient was disappointed with the final result, largely secondary to persistent pain. Finally, there was a fourth fracture that occurred in a patient who underwent RSA using a deltopectoral approach for CTA (Hamada V). The fracture was discovered 10 months postoperatively after the patient sustained a fall. Osteosynthesis was attempted using a tension band but failed, and hardware removal was eventually required. There was a residual 25 inferior acromial tilt and a persistent nonunion. The final Constant score was only 43 points due to the dissatisfaction of the patient with the results. The patient declined further intervention.
Table III Effects of inferior acromial tilt on Constant score and active elevation
Constant Score Active elevation
No tilt 18 cases
Tilt 29 cases
Normal acromion 287 cases
55.2 119
62.47 138
57.5 124
All 4 of the postoperative fractures of the scapular spine were discovered within the first year after the surgical intervention. Three of the 4 did not have any history of trauma. RSA was secondary to CTA in 2 cases, revision hemiarthroplasty in 1, and a failed coracoid transfer with a massive cuff tear in 1. The mean Constant score for these 4 cases was 35 points and mean active elevation was only 81 . Postoperative lesions of the scapular spine had significantly worse results than patients with acromial fracturefragmentation, os acromiale, or without acromial pathology. The average Constant score was significantly less than all other patients with acromial pathology (P ¼ .02). The same held true when this group was compared with those free of acromial lesions (P ¼ .04). Active elevation and subjective results were significantly worse than others with acromial pathology (P ¼ .007).
Discussion The surprisingly good results of our patients with preoperative acquired or congenital acromial pathology confirm the good results already reported by Mottier.12 Given the importance of the deltoid, any condition compromising the acromion and deltoid insertion is of legitimate concern for any patient contemplating RSA. There are 3 potential explanations for this surprising results. First, the main part of the deltoid is still attached firmly to the spine of the scapula and clavicle and is obviously strong enough to compensate for the middle part. Second, the less satisfactory Constant score and active forward elevation observed in the global series could be explained by the number of patients with fracture sequaela, post-traumatic arthritis, or revision arthroplasty, which are known to have less
Acromial insufficiency in reverse shoulder arthroplasties Table IV
Center 1 Center 2 Center 3 Center 4 Center 5 Total
501
Distribution of types of acromial pathology by surgical center Os acromiale
Acromial fragmentation
Acromial fracture
Preop scapular spine fracture
Postop scapular spine fracture
Number of cases
0 9 6 3 4 23
O 1 2 2 2 7
0 4 5 1 0 10
0 1 0 0 0 1
0 2 1 1 0 4
9 225 86 79 58 457
satisfactory results.17 Third, it has been shown by Favard and Nyffeler4,14 that the scapulothoracic motion is more important that the glenohumeral one with Reverse shoulder prosthesis. The scapulothoracic motion is not altered by an eventual abutment between the acromion and the greater tuberosity, and could explain that the patients with a severe tilt have the same range of motion that the patient without acromial tilt. In our series of 457 reverse prostheses, 23 (5.0%) presented with an os acromiale. Os acromiale is a congenital anomaly found in 1-15% of the general population, which was comparable to the frequency found in our series.10,11 Some authors have recommended aggressive surgical treatment for these lesions.9 Osteosynthesis of the free fragment when performing RSA would theoretically conserve the deltoid insertion and allow better arm elevation. Osteosynthesis would seem to be difficult in the face of significant lengthening of the deltoid and tension across the deltoid insertion. Additionally, the good results obtained without osteosynthesis lead us to question the utility of this approach. The poor results obtained by Rittmeister and the open reduction internal fixation of an os acromiale performed in our studies group support this position.15 Fracture-fragmentation present in 17 cases (3.7%) appear to be acquired secondary to contact between the humeral head and acromion. This lesion is represented by acromial acetabulization previously described by Neer in his description of CTA, and Hamada noted it in stage III of his classification. In the current series, we have found it in 4 of 8 stage III patients and 8 of 17 stage IVB patients. The acquired lesions of the acromion (fracture or fragmentation) were frequently displaced by the increased tension of the deltoid, but there was no statistically significant effect on postoperative Constant score, active elevation, or subjective result. Postoperative acromial complications after RSA have been described previously in the literature. Rittmeister et al reported 3 cases of reoperations for nonunion of the acromion.15 These cases were all patients with rheumatoid arthritis and utilized a trans-acromial approach with a sagittal osteotomy.7 Werner et al reported 4 cases of acromial or scapular spine fracture in 58 patients.18 Two cases underwent a second procedure, but no details are given regarding the preoperative status of the acromion or type of postoperative fracture. In a series of 60 cases, Frankle et al noted 1 case of
Figure 5
Postoperative fracture of the scapular spine.
scapular spine fracture that occurred 3 months postoperatively and healed spontaneously.5 Two additional cases of acromial fracture were discovered 1 year after the original interventions. One case healed spontaneously and the other required operative fixation. These cases reported by Frankle are similar to the 4 postoperative fractures of the scapular spine that we observed. For all cases, the preoperative acromion was normal and immediate postoperative radiographs showed no sign of fracture. Postoperative fractures of the scapular spine had the worst results in terms of Constant score, active elevation, and subjective satisfaction of all groups. This rare complication (0.8% of our series) should be suspected whenever rehabilitation progresses slowly, is painful, or suddenly deteriorates within the first year. It would be difficult to suggest that the 4 cases we observed were secondary to excessive deltoid tension because weak
502 and osteopenic bone was common to most of the elderly female patients in this series, and the surgical technique was the same for all. The surgical approach cannot be implicated, as we observed the same frequency using the deltopectoral and superolateral approaches. Taking into account the mediocre results obtained and the difficulty of stabilizing an osteoporotic bone under the increased tension of an elongated deltoid, it would seem reasonable to recommend immediate operative fixation using a plate and screw construct associated with postoperative immobilization on a 60 abduction splint in order to avoid nonunion and acromio-humeral contact secondary to inferior acromial tilt. The reported results of Werner and Frankle question the effectiveness of attempted internal fixation.18 Our failed attempt at osteosynthesis also does not allow us to comment on the effectiveness of this technique. At the moment, we recommend a conservative treatment with an abduction splint for 6 weeks to limit pain and acromial tilt, but can not comment on results yet. This study indicates that both acquired and congenital preoperative lesions of the acromion are not a contraindication to RSA. The results obtained are not different from patients with normal acromia. Postoperative fractures of the scapular spine have poor results and early treatment is recommended as soon as they are diagnosed.
Acknowledgments Several of the authors of this paper have disclosed that they receive royalties from Tornier for the reverse prosthesis studied in this paper.
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