- Email: [email protected]
The SMR reverse shoulder prosthesis in the treatment of cuff-deficient shoulder conditions
J Shoulder Elbow Surg (2009) 18, 622-626
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The SMR reverse shoulder prosthesis in the treatment of cuff-deficient shoulder conditions Simon W. Young, Ngozi M. Everts, Craig M. Ball, FRACS, Tim M. Astley, FRACS, Peter C. Poon, FRACS* Department of Orthopaedic Surgery, North Shore Hospital, Auckland, New Zealand Background: Reverse total shoulder arthroplasty (RSA) is a relatively recent concept that provides further options in the management of cuff-deficient shoulder disorders. While early results utilizing the Delta III prosthesis (DePuy, Warsaw, IN) have been promising, there is limited data in the literature on outcomes utilizing differing prosthetic designs. We report on the outcomes of Reverse total shoulder arthroplasty (RSA) utilizing a previously unreported prosthesis, the SMR Modular Shoulder System (Systema Multiplana Randelli, Lima-LTO, Italy). Material and methods: 49 arthroplasties in 48 patients who underwent Reverse Shoulder Arthroplasty with the SMR prosthesis were available for follow up. There were 10 males and 38 females with a mean age of 78.9 years (55-94) at time of operation. The most common indications were cuff tear arthropathy and osteoarthritis with cuff deficiency (66%), followed by fracture and fracture sequelae (16%). Results: At a mean 38 months follow up, 89% of patients rated their outcome as good or excellent. The mean American Shoulder and Elbow Surgeon Score was 70.1 (range 3-100), and the mean Oxford Shoulder Score 22.0 (12-47). The mean active anterior elevation was 122 degrees (range 45-180) and the mean external rotation 14.7 degrees (25-75). Inferior glenoid notching was seen in 24% of patients. There was no radiological evidence of component loosening and no reoperations. Conclusion: Modern RSA designs give encouraging results in the treatment of cuff deficient shoulder conditions. Our early experience with the SMR RSA shows favourable outcomes and a low rate of complications. Level of evidence: Level 4; Retrospective case series, no control group. Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Reverse; shoulder; arthroplasty; SMR, cuff tear arthropathy; RSA
Reverse total shoulder arthroplasty (RSA) is a relatively recent concept that provides further options in the management of shoulder disorders. Its nonanatomic design medializes the center of rotation, improving the deltoid muscle’s lever arm, which allows improved range of motion *Reprint requests: Peter C. Poon, FRACS, Private Bag 93-503, Takapuna, Auckland 0740, New Zealand. E-mail address: [email protected] (P.C. Poon).
in the absence of a functioning rotator cuff. Indications include rotator cuff arthropathy, massive rotator cuff tear, severe proximal humeral fractures, and revision after failure of previous total shoulder arthroplasty or hemiarthroplasty. Published series using the Delta, or Grammont, RSA (DePuy, Warsaw, IN) have reported improved range of motion and pain relief; however, high complication rates remain a concern. We report on a series using a previously unreported reverse prosthesis, the SMR
1058-2746/2009/$36.00 - see front matter Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees. doi:10.1016/j.jse.2009.01.017
Reverse shoulder arthroplasty with SMR prosthesis
623 Table I
Figure 1
SMR prosthesis.
Modular Shoulder System (Systema Multiplana Randelli; Lima-LTO, San Daniele del Friuli, Italy) (Figure 1).
Methods Between January 2004 and July 2006, 56 consecutive total shoulder arthroplasties in 55 patients were performed at a single institution by 3 experienced specialist shoulder surgeons. At a minimum follow-up of 24 months, 5 patients had died from unrelated causes, 1 had moved overseas, and 1 was not able to be contacted, leaving 49 shoulders in 48 patients available for clinical and radiologic follow-up at a mean of 38 months (range, 24-66 months) after surgery. There were 10 men and 38 women with a mean age of 78.9 years (range, 55-94 years) at the time of operation. Indications for surgery are shown in Table I. The most common indications were cuff tear arthropathy and osteoarthritis with cuff deficiency (66%), followed by fracture and fracture sequelae (such as nonunion) (16%). Reverse shoulder arthroplasty was used as a salvage procedure after previous failed arthroplasty (4 patients [8%]) and in 1 case of chronic dislocation (2%).
Operative technique The procedure was performed via a deltopectoral approach in 43 cases (88%) and a superolateral approach with anterior deltoid release in 6 cases (12%). Tenotomy of the biceps tendon was performed in patients in whom it was intact, and the long head of the triceps was released from the lateral border of the scapula. The glenoid baseplate was placed inferiorly on the glenoid such that the baseplate was flush with the inferior border of the glenoid and secured in an uncemented fashion with a central peg and supplementary variable-angle 6.5-mm screws proximally and distally in a divergent fashion. In 6 cases (12%), a glenosphere eccentric by 4 mm was placed at the 6-o’clock position, lowering the glenosphere further. Humeral fixation of the stem was uncemented in 41 cases (86%) and supplemented with cement in 8 cases (16%). Patients commenced passive range-of-motion exercises on day 1 postoperatively, and the arm was protected in a sling for 6 weeks. External rotation past neutral and active internal rotation were restricted to protect the subscapularis repair,
Indications for surgery
Indication
No. of shoulders (N ¼ 49)
%
Cuff tear arthropathy Osteoarthritis with cuff tear Fracture/fracture sequelae Failed total shoulder arthroplasty or hemiarthroplasty Massive cuff tear Rheumatoid arthritis Chronic dislocation
19 14 8 4
39% 29% 16% 8%
2 1 1
4% 2% 2%
with active-assisted exercises and gradual progression to independent activities commencing at 2 weeks.
Assessment At the time of follow-up, clinical assessment including range-ofmotion measurements was performed on all patients by a single trained observer. Outcomes were measured by use of American Shoulder and Elbow Surgeons scores,4 Oxford Shoulder Scores,10 visual analog pain scores, and overall patient satisfaction questions. Radiographic follow-up was done by use of standard anteroposterior and axillary lateral radiographs, and assessment of radiologic outcomes such as notching and loosening was performed independently by 2 trained observers.
Statistical analysis To compare outcome scores, range of motion, and pain scores, a Wilcoxon rank sum 2-sided test was performed. P < .05 was considered significant.
Results Outcomes at a mean follow-up of 38 months are shown in Table II. Overall, 89% of patients rated their outcome as good or excellent. At the time of follow-up, 45 patients (92%) had no or minimal pain as measured with a visual analog score. The American Shoulder and Elbow Surgeons scores were not significantly affected by age, gender, diagnosis, or surgical approach, although the numbers in each group were small. The mean active anterior elevation was 122 (range, 45 -180 ), and the mean external rotation 14.7 (range, 25 -75 ). No patient was able to internally rotate further than the hand reaching the ipsilateral buttock. Complications occurred in 4 patients (8%). There were 2 axillary nerve neurapraxias, which spontaneously resolved. One patient had a pulmonary embolus postoperatively and was treated with anticoagulants. In 1 patient undergoing revision to a reverse prosthesis, dislocation occurred postoperatively after a fall; this was reduced in the emergency department and remained stable. There were no reoperations. Inferior scapular notching was seen in 12 patients (24%). In all cases, the scapular notching was less than
624 Table II
S.W. Young et al. Outcomes at mean of 38 months’ follow-up Overall (N ¼ 49)
Outcome
Mean
Range
Notching (n ¼ 12) (mean)
No notching (n ¼ 37) (mean)
P value
ASES score Oxford Shoulder Score Anterior elevation ( ) External rotation ( ) Satisfaction (1-5) Pain score on visual analog scale
70.1 22.0 122.0 14.7 3.9 1.8
3-100 12-47 45-180 25-75 1-5 0-10
64.4 25.8 113 19 3.5 2.4
72.0 20.7 125 13 4.0 1.6
.49 .26 .30 .41 .30 .32
ASES, American Shoulder and Elbow Surgeons.
5 mm and did not reach the inferior screw (Figure 2); however, in view of the variable-angle nature of the inferior screw in this prosthetic design, the classification of inferior notching of Nerot and colleagues22 could not be applied. The mean outcome scores were lower in patients with notching, but the differences were not statistically significant. No radiographic evidence of glenoid or humeral component loosening was seen.
Discussion Reverse shoulder arthroplasty provides an additional option in the management of shoulder conditions with concomitant or pre-existing rotator cuff deficiency. Early ‘‘constrained’’ designs of reverse shoulder implants were complicated by early failure of the glenoid component8; however, the introduction of the Grammont prosthesis (Delta III; DePuy) has led to a renewed interest in reverse shoulder arthroplasty. Published results of the Delta III implant at short- to medium-term follow-up have been promising,6,9,16,20,25 with improved range of motion and pain relief. Recent reports on the Reverse Shoulder Prosthesis (RSP) (Encore Medical, Austin, TX)12 have also shown favorable outcomes, however, the high rates of early complications remain a concern. This study represents the first large series using the SMR prosthesis (Table III). At our institution, we began performing reverse shoulder arthroplasty in 1999 using the Delta III reverse total shoulder system. As a result of some early concerns regarding glenoid fixation with this prosthesis,7,17 in 2003, we began using the SMR system, originally designed by Professor Mario Randelli in 1994. This prosthesis has a number of features aimed at improving both initial and long-term glenoid fixation. The glenoid baseplate has a curved backing, which has been shown biomechanically to provide superior shear resistance in studies on total shoulder arthroplasty.2,3 The large tapered central peg compresses surrounding cancellous bone for primary fixation and has a porous hydroxyapatite coating to allow subsequent osteointegration.1 Finally, the large 6.5-mm-diameter screws can be inserted at variable angles,
Figure 2 Radiograph showing prosthesis in situ and small inferior scapular notch.
enabling the surgeon to maximize fixation with the available glenoid bone stock. No cases of glenoid loosening were seen in our series at this early follow-up. Inferior scapular notching was seen in 24% of patients in our series, which compares well with published rates of
Reverse shoulder arthroplasty with SMR prosthesis Table III
625
Published results of larger series in RSA
Author
Year Prosthesis
De Buttet et al11 Valenti et al22 Sirveaux et al20 Werner et al25 Boileau et al5 Wall et al24
1997 2001 2004 2005 2005 2007
Bufquin et al9 Levy et al15 Levy et al16 Frankle et al12 Terragnoli et al21 Current study
2007 2007 2007 2005 2007 2009
No. of Age Diagnosisa cases (mean) (y)
Delta III 71 Delta III 39 Delta III 80 Delta III 58 Delta III 45 Delta III/ 186 Aequalis Delta III 43 RSP 29 RSP 19 RSP 60 SMR reverse 18 SMR reverse 49
NS 70 73 68 72 73
1 1, 1 1, 1, 1,
78 69 72 71 75 79
3 4 4 1, 2, 6 3 1, 2, 3, 4, 6
Length of Satisfied Constant follow-up (%) score (mo)
24 84 44.5 4 38 3, 4 40 2, 3, 4, 5, 6 40 4
22 35 44 33 6 38
Reoperation Flexion External rotation ( ) ( )
NS NS NS NS 78% 93%
69 63 65.5 64 59 59.7
4.2% 15% 5% 33% 13% NS
120 NS 138 100 121 137
NS NS 11 12 11 6
NS 79% 79% 95% NS 89%
44 52.1 (ASES) 61 (ASES) 68.2 (ASES) 59 70.1 (ASES)
NS 21% 32% 15% NS 0%
97 73 76 105 NS 122
8 18 NS 35.9 NS 14.7
NS, Not stated; ASES, American Shoulder and Elbow Surgeons Score. a A diagnosis of 1 indicates rotator cuff tear arthropathy/osteoarthritis with cuff tear; 2, post-traumatic arthritis; 3, fracture and fracture sequelae; 4, failed hemiarthroplasty or total shoulder arthroplasty; 5, tumor on proximal humerus; and 6, rheumatoid arthritis.
44% to 96% with the Delta III prosthesis.17,19,20,23,25 This may in part be attributed to surgical technique, with the glenoid baseplate positioned as inferiorly as possible at the margin of the glenoid. More recently, in patients thought intraoperatively to be at risk of inferior impingement, we have attempted to minimize notching with an eccentric glenosphere placed at the 6-o’clock position. In the 6 cases in this series where an eccentric glenosphere was used, no notching was seen on follow-up radiographs. A prospective randomized trial comparing eccentric versus centric glenospheres is currently in progress. Frankle et al12 reported 0% notching in 60 patients in whom the RSP was used, thought to be because of the relatively more lateralized center of rotation. However, this may have come at the expense of increased stresses at the glenoid boneeprosthesis interface, with a glenoid component failure rate of 12% seen at 3 years’ follow-up. Our findings are in keeping with previous reports on reverse shoulder arthroplasty showing good return of active elevation postoperatively but limited external rotation (Table III). Gerber et al13 attempted to address this with the addition of a latissimus dorsi tendon transfer to restore muscle power; however, although there was a subjective improvement in external rotation function, the measured range-of-motion gains were small, suggesting that the limitation of movement is related to the semiconstrained prosthetic design in the SMR and Delta prostheses. Better results in terms of external rotation were seen with the RSP,12 perhaps as a result of a more lateralized center of rotation. In addition, no patient in our series was able to internally rotate further than the hand reaching the ipsilateral buttock, again likely because of the semiconstrained design. This has important implications in bilateral procedures for perineal hygiene, and for this reason, 1 patient in our series,
though satisfied with the outcome of his RSA, requested a hemiarthroplasty be performed when his contralateral side subsequently required surgery. Our study has a number of limitations. The retrospective nature of the study meant that preoperative range of motion and functional scores were not able to be analyzed. However, our results compare well with other published reports using other reverse prostheses (Table III). Second, the mean follow-up of 38 months is short in the context of arthroplasty surgery, and concerns regarding the longevity of the functional results of RSA remain.14 In addition, all patients in this series were operated on by specialist shoulder arthroplasty surgeons, leading to the possibility of selection bias, and less experienced surgeons may obtain differing results.18 In summary, modern designs of reverse shoulder arthroplasty yield encouraging results in the treatment of cuffdeficient shoulder conditions. Although it is too early to reliably predict the effects of differing prosthetic designs on long-term outcomes, our early experience with the SMR RSA shows favorable results and a low rate of complications.
Acknowledgments No funding grants were received in support of this study. One of the authors (Peter C. Poon) has previously received a financial grant towards a research fund from Lima.
References 1. Ahir SP, Walker PS, Squire-Taylor CJ, Blunn GW, Bayley JI. Analysis of glenoid fixation for a reversed anatomy fixed-fulcrum shoulder replacement. J Biomech 2004;37:1699-708.
626 2. Anglin C, Wyss UP, Nyffeler RW, Gerber C. Loosening performance of cemented glenoid prosthesis design pairs. Clin Biomech (Bristol, Avon) 2001;16:144-50. 3. Anglin C, Wyss UP, Pichora DR. Mechanical testing of shoulder prostheses and recommendations for glenoid design. J Shoulder Elbow Surg 2000;9:323-31. 4. Beaton DE, Richards RR. Measuring function of the shoulder. A crosssectional comparison of five questionnaires. J Bone Joint Surg Am 1996;78:882-90. 5. Boileau P, Watkinson DJ, Hatzidakis AM, Balg F. Grammont reverse prosthesis: design, rationale, and biomechanics. J Shoulder Elbow Surg 2005;14:147S-61S. 6. Boileau P, Watkinson DJ, Hatzidakis AM, Hovorka I. Neer Award 2005: The Grammont reverse shoulder prosthesis: results in cuff tear arthritis, fracture sequelae, and revision arthroplasty. J Shoulder Elbow Surg 2006:527-40. 7. Boulahia A, Edwards TB, Walch G, Baratta RV. Early results of a reverse design prosthesis in the treatment of arthritis of the shoulder in elderly patients with a large rotator cuff tear. Orthopedics 2002;25:129-33. 8. Brostro¨m LA, Wallensten R, Olsson E, Anderson D. The Kessel prosthesis in total shoulder arthroplasty. A five-year experience. Clin Orthop Relat Res 1992:155-60. 9. Bufquin T, Hersan A, Hubert L, Massin P. Reverse shoulder arthroplasty for the treatment of three- and four-part fractures of the proximal humerus in the elderly: a prospective review of 43 cases with a short-term follow-up. J Bone Joint Surg Br 2007;89:516-20. 10. Dawson J, Fitzpatrick R, Carr A. Questionnaire on the perception of patients about shoulder surgery. J Bone Joint Surg Br 1996;78: 593-600. 11. De Buttet M, Boucho Y, Capon D, Delfosse J. Grammont shoulder arthroplasty for osteoarthritis with massive rotator cuff tears. Reports of 71 cases [abstract]. J Shoulder Elbow Surg 1997;6:197. 12. Frankle M, Siegal S, Pupello D, Siegal S, Saleem A, Mighell M, et al. The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. A minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am 2005;87: 1697-705. 13. Gerber C, Pennington SD, Lingenfelter EJ, Sukthankar A. Reverse Delta-III total shoulder replacement combined with latissimus dorsi transfer. A preliminary report. J Bone Joint Surg Am 2007;89:940-7.
S.W. Young et al. 14. Guery J, Favard L, Sirveaux F, Oudet D, Mole D, Walch G. Reverse total shoulder arthroplasty. Survivorship analysis of eighty replacements followed for five to ten years. J Bone Joint Surg Am 2006;88:1742-7. 15. Levy J, Frankle M, Mighell M, Pupello D. The use of the reverse shoulder prosthesis for the treatment of failed hemiarthroplasty for proximal humeral fracture. J Bone Joint Surg Am 2007;89:292-300. 16. Levy JC, Virani N, Pupello D, Frankle M. Use of the reverse shoulder prosthesis for the treatment of failed hemiarthroplasty in patients with glenohumeral arthritis and rotator cuff deficiency. J Bone Joint Surg Br 2007;89:189-95. 17. Rittmeister M, Kerschbaumer F. Grammont reverse total shoulder arthroplasty in patients with rheumatoid arthritis and nonreconstructible rotator cuff lesions. J Shoulder Elbow Surg 2001;10:17-22. 18. Rockwood CA Jr. The reverse total shoulder prosthesis. The new kid on the block. J Bone Joint Surg Am 2007;89:233-5. 19. Simovitch RW, Zumstein MA, Lohri E, Helmy N, Gerber C. Predictors of scapular notching in patients managed with the Delta III reverse total shoulder replacement. J Bone Joint Surg Am 2007; 89:588-600. 20. Sirveaux F, Favard L, Oudet D, Huquet D, Walch C, Mole´ D. Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture of the cuff. Results of a multicentre study of 80 shoulders. J Bone Joint Surg Br 2004;86:388-95. 21. Terragnoli F, Zattoni G, Damiani L, Cabrioli A, Li Bassi G. Treatment of proximal humeral fractures with reverse prostheses in elderly patients. J Orthopaed Traumatol 2007;8:71-6. 22. Valenti PH, Boutens D, Nerot C. Delta 3 reversed prosthesis for osteoarthritis with massive rotator cuff tear: long term results (>5 years). In: Walch G, Boileau P, Mole´ D, editors. 2000 Prosthe`ses d’e´paule.recul de 2 a` 10 ans. Paris: Sauramps Me´dical; 2001. p. 253-9. 23. Vanhove B, Beugnies A. Grammont’s reverse shoulder prosthesis for rotator cuff arthropathy. A retrospective study of 32 cases. Acta Orthop Belg 2004;70:219-25. 24. Wall B, Nove´-Josserand L, O’Connor DP, Edwards TB, Walch G. Reverse total shoulder arthroplasty: a review of results according to etiology. J Bone Joint Surg Am 2007;89:1476-85. 25. Werner CM, 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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The SMR reverse shoulder prosthesis in the treatment of cuff-deficient shoulder conditions Simon W. Young, Ngozi M. Everts, Craig M. Ball, FRACS, Tim M. Astley, FRACS, Peter C. Poon, FRACS* Department of Orthopaedic Surgery, North Shore Hospital, Auckland, New Zealand Background: Reverse total shoulder arthroplasty (RSA) is a relatively recent concept that provides further options in the management of cuff-deficient shoulder disorders. While early results utilizing the Delta III prosthesis (DePuy, Warsaw, IN) have been promising, there is limited data in the literature on outcomes utilizing differing prosthetic designs. We report on the outcomes of Reverse total shoulder arthroplasty (RSA) utilizing a previously unreported prosthesis, the SMR Modular Shoulder System (Systema Multiplana Randelli, Lima-LTO, Italy). Material and methods: 49 arthroplasties in 48 patients who underwent Reverse Shoulder Arthroplasty with the SMR prosthesis were available for follow up. There were 10 males and 38 females with a mean age of 78.9 years (55-94) at time of operation. The most common indications were cuff tear arthropathy and osteoarthritis with cuff deficiency (66%), followed by fracture and fracture sequelae (16%). Results: At a mean 38 months follow up, 89% of patients rated their outcome as good or excellent. The mean American Shoulder and Elbow Surgeon Score was 70.1 (range 3-100), and the mean Oxford Shoulder Score 22.0 (12-47). The mean active anterior elevation was 122 degrees (range 45-180) and the mean external rotation 14.7 degrees (25-75). Inferior glenoid notching was seen in 24% of patients. There was no radiological evidence of component loosening and no reoperations. Conclusion: Modern RSA designs give encouraging results in the treatment of cuff deficient shoulder conditions. Our early experience with the SMR RSA shows favourable outcomes and a low rate of complications. Level of evidence: Level 4; Retrospective case series, no control group. Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Reverse; shoulder; arthroplasty; SMR, cuff tear arthropathy; RSA
Reverse total shoulder arthroplasty (RSA) is a relatively recent concept that provides further options in the management of shoulder disorders. Its nonanatomic design medializes the center of rotation, improving the deltoid muscle’s lever arm, which allows improved range of motion *Reprint requests: Peter C. Poon, FRACS, Private Bag 93-503, Takapuna, Auckland 0740, New Zealand. E-mail address: [email protected] (P.C. Poon).
in the absence of a functioning rotator cuff. Indications include rotator cuff arthropathy, massive rotator cuff tear, severe proximal humeral fractures, and revision after failure of previous total shoulder arthroplasty or hemiarthroplasty. Published series using the Delta, or Grammont, RSA (DePuy, Warsaw, IN) have reported improved range of motion and pain relief; however, high complication rates remain a concern. We report on a series using a previously unreported reverse prosthesis, the SMR
1058-2746/2009/$36.00 - see front matter Ó 2009 Journal of Shoulder and Elbow Surgery Board of Trustees. doi:10.1016/j.jse.2009.01.017
Reverse shoulder arthroplasty with SMR prosthesis
623 Table I
Figure 1
SMR prosthesis.
Modular Shoulder System (Systema Multiplana Randelli; Lima-LTO, San Daniele del Friuli, Italy) (Figure 1).
Methods Between January 2004 and July 2006, 56 consecutive total shoulder arthroplasties in 55 patients were performed at a single institution by 3 experienced specialist shoulder surgeons. At a minimum follow-up of 24 months, 5 patients had died from unrelated causes, 1 had moved overseas, and 1 was not able to be contacted, leaving 49 shoulders in 48 patients available for clinical and radiologic follow-up at a mean of 38 months (range, 24-66 months) after surgery. There were 10 men and 38 women with a mean age of 78.9 years (range, 55-94 years) at the time of operation. Indications for surgery are shown in Table I. The most common indications were cuff tear arthropathy and osteoarthritis with cuff deficiency (66%), followed by fracture and fracture sequelae (such as nonunion) (16%). Reverse shoulder arthroplasty was used as a salvage procedure after previous failed arthroplasty (4 patients [8%]) and in 1 case of chronic dislocation (2%).
Operative technique The procedure was performed via a deltopectoral approach in 43 cases (88%) and a superolateral approach with anterior deltoid release in 6 cases (12%). Tenotomy of the biceps tendon was performed in patients in whom it was intact, and the long head of the triceps was released from the lateral border of the scapula. The glenoid baseplate was placed inferiorly on the glenoid such that the baseplate was flush with the inferior border of the glenoid and secured in an uncemented fashion with a central peg and supplementary variable-angle 6.5-mm screws proximally and distally in a divergent fashion. In 6 cases (12%), a glenosphere eccentric by 4 mm was placed at the 6-o’clock position, lowering the glenosphere further. Humeral fixation of the stem was uncemented in 41 cases (86%) and supplemented with cement in 8 cases (16%). Patients commenced passive range-of-motion exercises on day 1 postoperatively, and the arm was protected in a sling for 6 weeks. External rotation past neutral and active internal rotation were restricted to protect the subscapularis repair,
Indications for surgery
Indication
No. of shoulders (N ¼ 49)
%
Cuff tear arthropathy Osteoarthritis with cuff tear Fracture/fracture sequelae Failed total shoulder arthroplasty or hemiarthroplasty Massive cuff tear Rheumatoid arthritis Chronic dislocation
19 14 8 4
39% 29% 16% 8%
2 1 1
4% 2% 2%
with active-assisted exercises and gradual progression to independent activities commencing at 2 weeks.
Assessment At the time of follow-up, clinical assessment including range-ofmotion measurements was performed on all patients by a single trained observer. Outcomes were measured by use of American Shoulder and Elbow Surgeons scores,4 Oxford Shoulder Scores,10 visual analog pain scores, and overall patient satisfaction questions. Radiographic follow-up was done by use of standard anteroposterior and axillary lateral radiographs, and assessment of radiologic outcomes such as notching and loosening was performed independently by 2 trained observers.
Statistical analysis To compare outcome scores, range of motion, and pain scores, a Wilcoxon rank sum 2-sided test was performed. P < .05 was considered significant.
Results Outcomes at a mean follow-up of 38 months are shown in Table II. Overall, 89% of patients rated their outcome as good or excellent. At the time of follow-up, 45 patients (92%) had no or minimal pain as measured with a visual analog score. The American Shoulder and Elbow Surgeons scores were not significantly affected by age, gender, diagnosis, or surgical approach, although the numbers in each group were small. The mean active anterior elevation was 122 (range, 45 -180 ), and the mean external rotation 14.7 (range, 25 -75 ). No patient was able to internally rotate further than the hand reaching the ipsilateral buttock. Complications occurred in 4 patients (8%). There were 2 axillary nerve neurapraxias, which spontaneously resolved. One patient had a pulmonary embolus postoperatively and was treated with anticoagulants. In 1 patient undergoing revision to a reverse prosthesis, dislocation occurred postoperatively after a fall; this was reduced in the emergency department and remained stable. There were no reoperations. Inferior scapular notching was seen in 12 patients (24%). In all cases, the scapular notching was less than
624 Table II
S.W. Young et al. Outcomes at mean of 38 months’ follow-up Overall (N ¼ 49)
Outcome
Mean
Range
Notching (n ¼ 12) (mean)
No notching (n ¼ 37) (mean)
P value
ASES score Oxford Shoulder Score Anterior elevation ( ) External rotation ( ) Satisfaction (1-5) Pain score on visual analog scale
70.1 22.0 122.0 14.7 3.9 1.8
3-100 12-47 45-180 25-75 1-5 0-10
64.4 25.8 113 19 3.5 2.4
72.0 20.7 125 13 4.0 1.6
.49 .26 .30 .41 .30 .32
ASES, American Shoulder and Elbow Surgeons.
5 mm and did not reach the inferior screw (Figure 2); however, in view of the variable-angle nature of the inferior screw in this prosthetic design, the classification of inferior notching of Nerot and colleagues22 could not be applied. The mean outcome scores were lower in patients with notching, but the differences were not statistically significant. No radiographic evidence of glenoid or humeral component loosening was seen.
Discussion Reverse shoulder arthroplasty provides an additional option in the management of shoulder conditions with concomitant or pre-existing rotator cuff deficiency. Early ‘‘constrained’’ designs of reverse shoulder implants were complicated by early failure of the glenoid component8; however, the introduction of the Grammont prosthesis (Delta III; DePuy) has led to a renewed interest in reverse shoulder arthroplasty. Published results of the Delta III implant at short- to medium-term follow-up have been promising,6,9,16,20,25 with improved range of motion and pain relief. Recent reports on the Reverse Shoulder Prosthesis (RSP) (Encore Medical, Austin, TX)12 have also shown favorable outcomes, however, the high rates of early complications remain a concern. This study represents the first large series using the SMR prosthesis (Table III). At our institution, we began performing reverse shoulder arthroplasty in 1999 using the Delta III reverse total shoulder system. As a result of some early concerns regarding glenoid fixation with this prosthesis,7,17 in 2003, we began using the SMR system, originally designed by Professor Mario Randelli in 1994. This prosthesis has a number of features aimed at improving both initial and long-term glenoid fixation. The glenoid baseplate has a curved backing, which has been shown biomechanically to provide superior shear resistance in studies on total shoulder arthroplasty.2,3 The large tapered central peg compresses surrounding cancellous bone for primary fixation and has a porous hydroxyapatite coating to allow subsequent osteointegration.1 Finally, the large 6.5-mm-diameter screws can be inserted at variable angles,
Figure 2 Radiograph showing prosthesis in situ and small inferior scapular notch.
enabling the surgeon to maximize fixation with the available glenoid bone stock. No cases of glenoid loosening were seen in our series at this early follow-up. Inferior scapular notching was seen in 24% of patients in our series, which compares well with published rates of
Reverse shoulder arthroplasty with SMR prosthesis Table III
625
Published results of larger series in RSA
Author
Year Prosthesis
De Buttet et al11 Valenti et al22 Sirveaux et al20 Werner et al25 Boileau et al5 Wall et al24
1997 2001 2004 2005 2005 2007
Bufquin et al9 Levy et al15 Levy et al16 Frankle et al12 Terragnoli et al21 Current study
2007 2007 2007 2005 2007 2009
No. of Age Diagnosisa cases (mean) (y)
Delta III 71 Delta III 39 Delta III 80 Delta III 58 Delta III 45 Delta III/ 186 Aequalis Delta III 43 RSP 29 RSP 19 RSP 60 SMR reverse 18 SMR reverse 49
NS 70 73 68 72 73
1 1, 1 1, 1, 1,
78 69 72 71 75 79
3 4 4 1, 2, 6 3 1, 2, 3, 4, 6
Length of Satisfied Constant follow-up (%) score (mo)
24 84 44.5 4 38 3, 4 40 2, 3, 4, 5, 6 40 4
22 35 44 33 6 38
Reoperation Flexion External rotation ( ) ( )
NS NS NS NS 78% 93%
69 63 65.5 64 59 59.7
4.2% 15% 5% 33% 13% NS
120 NS 138 100 121 137
NS NS 11 12 11 6
NS 79% 79% 95% NS 89%
44 52.1 (ASES) 61 (ASES) 68.2 (ASES) 59 70.1 (ASES)
NS 21% 32% 15% NS 0%
97 73 76 105 NS 122
8 18 NS 35.9 NS 14.7
NS, Not stated; ASES, American Shoulder and Elbow Surgeons Score. a A diagnosis of 1 indicates rotator cuff tear arthropathy/osteoarthritis with cuff tear; 2, post-traumatic arthritis; 3, fracture and fracture sequelae; 4, failed hemiarthroplasty or total shoulder arthroplasty; 5, tumor on proximal humerus; and 6, rheumatoid arthritis.
44% to 96% with the Delta III prosthesis.17,19,20,23,25 This may in part be attributed to surgical technique, with the glenoid baseplate positioned as inferiorly as possible at the margin of the glenoid. More recently, in patients thought intraoperatively to be at risk of inferior impingement, we have attempted to minimize notching with an eccentric glenosphere placed at the 6-o’clock position. In the 6 cases in this series where an eccentric glenosphere was used, no notching was seen on follow-up radiographs. A prospective randomized trial comparing eccentric versus centric glenospheres is currently in progress. Frankle et al12 reported 0% notching in 60 patients in whom the RSP was used, thought to be because of the relatively more lateralized center of rotation. However, this may have come at the expense of increased stresses at the glenoid boneeprosthesis interface, with a glenoid component failure rate of 12% seen at 3 years’ follow-up. Our findings are in keeping with previous reports on reverse shoulder arthroplasty showing good return of active elevation postoperatively but limited external rotation (Table III). Gerber et al13 attempted to address this with the addition of a latissimus dorsi tendon transfer to restore muscle power; however, although there was a subjective improvement in external rotation function, the measured range-of-motion gains were small, suggesting that the limitation of movement is related to the semiconstrained prosthetic design in the SMR and Delta prostheses. Better results in terms of external rotation were seen with the RSP,12 perhaps as a result of a more lateralized center of rotation. In addition, no patient in our series was able to internally rotate further than the hand reaching the ipsilateral buttock, again likely because of the semiconstrained design. This has important implications in bilateral procedures for perineal hygiene, and for this reason, 1 patient in our series,
though satisfied with the outcome of his RSA, requested a hemiarthroplasty be performed when his contralateral side subsequently required surgery. Our study has a number of limitations. The retrospective nature of the study meant that preoperative range of motion and functional scores were not able to be analyzed. However, our results compare well with other published reports using other reverse prostheses (Table III). Second, the mean follow-up of 38 months is short in the context of arthroplasty surgery, and concerns regarding the longevity of the functional results of RSA remain.14 In addition, all patients in this series were operated on by specialist shoulder arthroplasty surgeons, leading to the possibility of selection bias, and less experienced surgeons may obtain differing results.18 In summary, modern designs of reverse shoulder arthroplasty yield encouraging results in the treatment of cuffdeficient shoulder conditions. Although it is too early to reliably predict the effects of differing prosthetic designs on long-term outcomes, our early experience with the SMR RSA shows favorable results and a low rate of complications.
Acknowledgments No funding grants were received in support of this study. One of the authors (Peter C. Poon) has previously received a financial grant towards a research fund from Lima.
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