Objectives

To date, no study has considered the impact of acromial morphology on shoulder range of movement (ROM). The purpose of our study was to evaluate the effects of lateralization of the centre of rotation (COR) and neck-shaft angle (NSA) on shoulder ROM after reverse shoulder arthroplasty (RSA) in patients with different scapular morphologies.

Aims

The aim of this study was to report the outcomes of different treatment options for glenoid loosening following reverse shoulder arthroplasty (RSA) at a minimum follow-up of two years.

Shoulder instability and impingement are common in tennis players. During tennis, several impingements could occur: subcoracoid and anterosuperior impingements at the follow-through phase of forehand and the backhand preparation phase; subacromial and postero-superior impingements at the cocking phase of serve. The precise causes for these impingements remain unclear, but it is believed that repetitive contact, glenohumeral instability may play a role.

Impingement and glenohumeral instability at critical tennis positions have never been dynamically evaluated in-vivo. The purpose of this study was to develop a patient-specific measurement technique based on motion capture and MRI to accurately determine glenohumeral kinematics (rotations and translations). The second objective was to evaluate impingements and stability in tennis.

Shoulder MR arthrography and motion capture were performed in 10 tennis players. Motion data were recorded during tennis movements. Glenohumeral kinematics was computed from the markers trajectories using a global optimisation algorithm with loose constraints on joint translations (accuracy: translational error ≈3mm, rotational error <4°). The translations patterns computed with the model were in good agreement with previous works. The resulting computed motions were applied to the subject's shoulder 3D bony models reconstructed from MRI data.

While simulating the shoulder joint, minimum humero-acromial, humero-coracoid and humero-glenoid distances were measured at critical tennis positions. Given the thickness of the potential impinged tissues, impingement was considered when the computed distance was <5 mm (<6 mm for the humero-acromial distance). During serve, glenohumeral stability was assessed at the cocking, deceleration and finish phases. Glenohumeral translation was defined as the anterior-posterior and superior-inferior motion of the humeral head centre relative to a glenoid coordinate system. Subluxation was defined as the ratio (in %) between the humeral head centre translation and the radius of the width (antero-posterior subluxation) or height (supero-inferior subluxation) of the glenoid surface. Instability was thus considered when the subluxation was >50%, corresponding to a loss of congruence superior to half the radius of the width (or height) of the glenoid.

No subcoracoid impingement was detected. Antero-superior impingements were observed in two subjects (29%) during forehand. Anterior and lateral subacromial impingements occurred during the cocking phase of serve in three (29%) and four subjects (42%), respectively. Postero-superior impingements during the cocking phase of serve were the most frequent (7 subjects, 75%). In this position, glenohumeral translation was anterior (mean: 34%) and superior (mean: 13%). During the deceleration phase, anterior and superior translation varied between 8–57% and between 5–34%, respectively. During the finish phase, anterior translation was slightly more intense (mean: 44%), while superior translation remained low (mean: 1%). MRI revealed eleven rotator cuff lesions in five subjects, and six labral lesions in five subjects.

Postero-superior impingement was frequent when serving. No instability could be noted. Tennis players presented frequent radiographic signs of structural lesions which seem to be mainly related to postero-superior impingement due to repetitive abnormal motion contacts. Our findings are consistent with this hypothesis. To our knowledge, this is the first study demonstrating that a dynamic and precise motion analysis of the shoulder is feasible using an external measurement system, such as motion capture.

The indications for reverse shoulder arthroplasty (RSA) continue to be expanded. Associated impairment of the deltoid muscle has been considered a contraindication to its use, as function of the RSA depends on the deltoid and impairment of the deltoid may increase the risk of dislocation. The aim of this retrospective study was to determine the functional outcome and risk of dislocation following the use of an RSA in patients with impaired deltoid function. Between 1999 and 2010, 49 patients (49 shoulders) with impairment of the deltoid underwent RSA and were reviewed at a mean of 38 months (12 to 142) post-operatively. There were nine post-operative complications (18%), including two dislocations. The mean forward elevation improved from 50° (sd 38; 0° to 150°) pre-operatively to 121° (sd 40; 0° to 170°) at final follow-up (p < 0.001). The mean Constant score improved from 24 (sd 12; 2 to 51) to 58 (sd 17; 16 to 83) (p < 0.001). The mean Single Assessment Numeric Evaluation score was 71 (sd 17; 10 to 95) and the rate of patient satisfaction was 98% (48 of 49) at final follow-up.

These results suggest that pre-operative deltoid impairment, in certain circumstances, is not an absolute contraindication to RSA. This form of treatment can yield reliable improvement in function without excessive risk of post-operative dislocation.

Cite this article: Bone Joint J 2013;95-B:1106–13.

Introduction

Large diameter metal on metal cups have been used in total hip arthroplasty advocating superior results with respect to dislocation rates, range of motion and long term survival. The Durom cup used as part of the Durom hip resurfacing system has been incriminated with poor short term results sometimes correlated to incorrect positioning of either the femoral or acetabular component. Our objective was to evaluate short term results of the Durom cup used in conjunction with standard stems.

Purpose of the study: Reversed prostheses provide improved active anterior elevation in shoulders free of cuff tears by lengthening the deltoid and increasing is lever arm. The purpose of this work was to search for a correlation between arm lengthening and postoperative active anterior elevation.

Material and methods: One hundred eighty-three reversed prostheses were reviewed with minimum one year follow-up for a complete clinical and radiographic work-up. Using a previously validated protocol, arm lengthening was assessed either in comparison with the contralateral side or with preoperative measurements. A statistical analysis was performed to search for a correlation between lengthening of the humerus and the arm with active anterior elevation.

Results: Considering the entire series, mean lengthening of the humerus was 0.2±1.4 cm (range −4.7 to +5.4). Postoperative active anterior elevation was 141±27 (range 30–180). There was no correlation between humerus lengthening or shortening and active anterior elevation (p=0.169). A shorter arm produced an active anterior elevation at 121 and 0 – 1 cm lengthening an active anterior elevation at 140; lengthening 1 – 2.5 cm gave active anterior elevation at 144 and beyond 2.5 cm 147. The difference in active anterior elevation was statistically significant (p< 0.001) between patients with a shortening and those with a lengthening.

Discussion: Arm lengthening corresponds to a lengthening of the humerus plus a lengthening of the infra-acromial space. We found a statistically negative correlation between arm shortening (and thus deltoid shortening) and active anterior elevation and a positive trend between lengthening and active anterior elevation. Our measurement did not take into account the increased lever arm of the deltoid and thus only partially expresses the improvement in deltoid function. Nevertheless, our study shows that objective evaluation of deltoid lengthening is possible pre- intra- and postoperatively and that this measurement can be correlated with postoperative functional outcome.

Purpose of the study: The purpose of this retrospective clinical and radiographic study was to analyse the long-term results obtained after Patte’s triple locking procedure for the treatment of anterior instability of the shoulder joint.

Material and methods: A questionnaire was sent to 574 patients who underwent the procedure performed by the same senior operator from 1986 to 2006. Variables studied wer the Walch-Duplay score (with pain score), patient satisfaction, postoperative complications and radiographic aspect.

Results: One hundred fifty patients (26%) responded and sent three radiographs. There were 107 men and 43 women, mean age 28.6±8.7 years (range 16–57). Mean follow-up was 14.6 years (range 2.8–22.6). One hundred seventeen patients (78%) were reviewed with follow-up greater than 10 years. Two patients (1.3%) experienced recurrent anterior instability; no revision was required. The Walch-Duplay scores were excellent or good in 146 patients (97.3%); 53% of patients were pain free; 34% had episodic pain, 9% moderate to mild pain and 4% severe pain. Resumption of sports activity was noted by 85% of patients. Overall, 79% of patients were very satisfied, 18% satisfied, and 3% not satisfied. Postoperative complications (2%) were one case each of infection, transient paresis of the musculocutaeous nerve, and superficial venous thrombosis. There were radiographic signs of an anomaly of the coracoids block in 13 patients (8%); non-union (n=3), lysis (n=4) fracture (n=2), migration (n=1), fracture of the ceramic washer (n=3). The block or washer overhang was noted in 19 patients (12.7%). Centred osteoarthritis was noted in 31% of patients (25% Samilson 1, 4% Samilson 2, 2% Samilson 3). There were two factors associated with long-term degenerative disease: age > 40 at surgery (p=0.02 and block overhang (p< 0.01).

Discussion: Patte’s triple locking procedure is an open procedure for the treatment of anterior shoulder instability. The technique is very minute and specific postoperative rehabilitation is needed. In these conditions, the operation is effective, providing good control of shoulder stability and allowing resumption of sports activities with a low complication rate. This study shows that long-term degenerative disease can be decreased if the patient undergoes surgery before the age of 40 years and if the coracoids block does not overhang.

Radiological changes and differences between cemented and uncemented components of Grammont reverse shoulder arthroplasties (DePuy) were analysed at a mean follow-up of 9.6 years (8 to 12). Of 122 reverse shoulder arthroplasties implanted in five shoulder centres between 1993 and 2000, a total of 68 (65 patients) were available for study. The indications for reversed shoulder arthroplasty were cuff tear arthropathy in 48 shoulders, revision of shoulder prostheses of various types in 11 and massive cuff tear in nine. The development of scapular notching, bony scapular spur formation, heterotopic ossification, glenoid and humeral radiolucencies, stem subsidence, radiological signs of stress shielding and resorption of the tuberosities were assessed on standardised true anteroposterior and axillary radiographs.

A scapular notch was observed in 60 shoulders (88%) and was associated with the superolateral approach (p = 0.009). Glenoid radiolucency was present in 11 (16%), bony scapular spur and/or ossifications in 51 (75%), and subsidence of the stem and humeral radiolucency in more than three zones were present in three (8.8%) and in four (11.8%) of 34 cemented components, respectively, and in one (2.9%) and two (5.9%) of 34 uncemented components, respectively. Radiological signs of stress shielding were significantly more frequent with uncemented components (p < 0.001), as was resorption of the greater (p < 0.001) and lesser tuberosities (p = 0.009).

Introduction: Clinically evident neurological injury of the operated limb after total shoulder arthroplasty is not uncommon. The purpose of this prospective study was to determine the incidence of subclinical neurological lesions after reverse shoulder arthroplasty and anatomic shoulder arthroplasty (group control), and to correlate its occurrence to postoperative lengthening of the arm.

Method: We included all patients needing a total shoulder arthroplasty either anatomic or reversed. Each patient underwent a pre- and postoperative electromyography (EMG). This study focused on the clinical, radiological and EMG evaluation, with a measure of the lengthening of the arm in case of reversed shoulder arthroplasty according to a protocol previously validated.

Result: Between November 2007 and February 2009, we collected 41 patients (42 prostheses), including 23 anatomic (group 1) and 19 reverse (group 2) primary shoulder arthroplasties. The 2 groups were similar according to mean age, comorbidity, male/female ratio and nerve conduction abnormalities on EMG performed on an average of 10 days before surgery. Control EMG realized at an average of 3.6 weeks postoperatively showed in group 1, a plexus lesion due to an intra-operative complication. In group 2, we noticed 9 recent neurological damages (45% of cases) involving mainly the axillary nerve; 8 were rapidly regressive. The incidence of recent injury was significantly more frequent in group 2 (p=0.003) with a risk 10.4 times higher (95% CI 1.4, 74.8). Mean lengthening of the arm after a reverse was 3.1 cm ± 1.8 (range 0.2 to 5.9) compared to preoperative measurement and 2.4 cm ± 2.1 (range −0.5 to 5.8) compared with the normal contra-lateral side.

Discussion: The occurrence of peripheral neurological lesion following a reverse shoulder arthroplasty is common but usually transient. These lesions may cause postoperative pain, alter rehabilitation and can theoretically induce prosthetic instability. Lengthening of the arm is considered as one of the major factors responsible for this neurologic damage. Indeed, surgical dissection, compression phenomena by use of retractors or presence of hematoma, vascular injury, mobilization of the upper limb and possibly interscalene block are similar for the two types of prosthesis. Arm lengthening is thus a compromise between necessary retensionning of the deltoid for good mobility and instability avoidance, and lengthening which may be responsible for neurological lesions, acromial fractures and permanent arm abduction.