Matthias A. Zumstein

Predictors of Scapular Notching in Patients Managed with the Delta III Reverse Total Shoulder Replacement

BACKGROUND The reverse Delta III shoulder prosthesis can relieve pain and restore function in patients with cuff tear arthropathy. The most frequently reported radiographic complication is inferior scapular notching. The purpose of the present study was to evaluate the clinical relevance of notching and to determine the anatomic and radiographic parameters that predispose to its occurrence. METHODS Seventy-seven consecutive shoulders in seventy-six patients with an irreparable rotator cuff deficiency were managed with a reverse Delta III shoulder arthroplasty and were followed clinically and radiographically for a minimum of twenty-four months. The effects of cranial-caudal glenoid component positioning and the prosthesis-scapular neck angle on the development of inferior scapular notching and clinical outcome were assessed. RESULTS All shoulders that had development of notching did so in the first fourteen months. Of the seventy-seven shoulders that were studied, thirty-four (44%) had inferior scapular notching, twenty-three (30%) had posterior notching, and six (8%) had anterior notching. Osteophytes along the inferior part of the scapula occurred in twenty-one (27%) of the seventy-seven shoulders. The angle between the glenosphere and the scapular neck (r = 0.667) as well as the craniocaudal position of the glenosphere (r = 0.654) were highly correlated with inferior notching (p < 0.001). A notching index was calculated with use of the height of implantation of the glenosphere and the postoperative prosthesis-scapular neck angle. This allowed prediction of the occurrence of notching with a sensitivity of 91% and specificity of 88%. The height of implantation of the glenosphere had approximately an eight times greater influence on inferior notching than the prosthesis-scapular neck angle did. Inferior scapular notching was associated with a significantly poorer clinical outcome. CONCLUSIONS Inferior scapular notching after reverse total shoulder arthroplasty adversely affects the intermediate-term clinical outcome. It can be prevented by optimal positioning of the glenoid component.

The clinical and structural long-term results of open repair of massive tears of the rotator cuff

BACKGROUND At a mean follow-up of 3.1 years, twenty-seven consecutive repairs of massive rotator cuff tears yielded good and excellent clinical results despite a retear rate of 37%. Patients with a retear had improvement over the preoperative state, but those with a structurally intact repair had a substantially better result. The purpose of this study was to reassess the same patients to determine the long-term functional and structural results. METHODS At a mean follow-up interval of 9.9 years, twenty-three of the twenty-seven patients returned for a review and were examined clinically, radiographically, and with magnetic resonance imaging with use of a methodology identical to that used at 3.1 years. RESULTS Twenty-two of the twenty-three patients remained very satisfied or satisfied with the result. The mean subjective shoulder value was 82% (compared with 80% at 3.1 years). The mean relative Constant score was 85% (compared with 83% at 3.1 years). The retear rate was 57% at 9.9 years (compared with 37% at 3.1 years; p = 0.168). Patients with an intact repair had a better result than those with a failed reconstruction with respect to the mean absolute Constant score (81 compared with 64 points, respectively; p = 0.015), mean relative Constant score (95% and 77%; p = 0.002), and mean strength of abduction (5.5 and 2.6 kg; p = 0.007). The mean retear size had increased from 882 to 1164 mm(2) (p = 0.016). Supraspinatus and infraspinatus muscle fatty infiltration had increased (p = 0.004 and 0.008, respectively). Muscles with torn tendons preoperatively showed more fatty infiltration than muscles with intact tendons preoperatively, regardless of repair integrity. Shoulders with a retear had a significantly higher mean acromion index than those without retear (0.75 and 0.65, respectively; p = 0.004). CONCLUSIONS Open repair of massive rotator cuff tears yielded clinically durable, excellent results with high patient satisfaction at a mean of almost ten years postoperatively. Conversely, fatty muscle infiltration of the supraspinatus and infraspinatus progressed, and the retear size increased over time. The preoperative integrity of the tendon appeared to be protective against muscle deterioration. A wide lateral extension of the acromion was identified as a previously unknown risk factor for retearing.

Problems, complications, reoperations, and revisions in reverse total shoulder arthroplasty: a systematic review

Department of Orthopaedic Surgery and Sports Traumatology, Hopital de L’Archet II, University of Nice Sophia-Antipolis, Nice, France Department of Orthopaedic Surgery and Traumatology, University of Bern, Inselspital, Bern, Switzerland Shoulder and Elbow Service, Section of Orthopaedic Surgery, University of Manitoba, Pan Am Clinic, Winnipeg, MB, Canada Department of Orthopaedic Surgery, Clinica Las Condes, Santiago, Chile

Long-term outcome after structural failure of rotator cuff repairs.

BACKGROUND In a previous study, twenty consecutive patients with a rerupture of the rotator cuff, as documented with magnetic resonance imaging, were found to have significantly less pain and better function and strength, compared with the preoperative state, at 3.2 years postoperatively. It was the purpose of this study to determine the clinical and structural outcomes of these reruptures in the same twenty patients after a longer period of follow-up. METHODS At a mean of 7.6 years postoperatively, the twenty patients were reexamined clinically and with standard radiographs and magnetic resonance imaging with use of the same clinical, radiographic, and magnetic resonance imaging criteria as were utilized in the review at 3.2 years. The mean age at the time of final follow-up was sixty-six years. RESULTS Nineteen of the twenty patients continued to be either very satisfied or satisfied with the outcome. The relative Constant score averaged 88% and was not significantly different from the score at 3.2 years, which averaged 83%. The mean scores for pain, function, and strength also had not changed significantly. Overall, the twenty reruptures had not increased in size, and eight of them had healed structurally at the time of the 7.6-year follow-up. Seven of these eight reruptures had been of the supraspinatus tendon only, and seven had been smaller than 400 mm(2) at 3.2 years. Twelve reruptures persisted, and five were larger than the preoperative tear. Fatty infiltration of the infraspinatus muscle progressed significantly (p = 0.015) and the acromiohumeral distance decreased significantly (p = 0.006) between the two follow-up periods. Neither fatty infiltration of the supraspinatus and subscapularis muscles nor glenohumeral osteoarthritis progressed significantly. CONCLUSIONS At an average of 7.6 years, the clinical outcomes after structural failure of rotator cuff repairs remained significantly improved over the preoperative state in terms of pain, function, strength, and patient satisfaction. Overall, the reruptures that had been present at 3.2 years did not increase in size. We also found that reruptures of the supraspinatus that had been smaller than 400 mm(2) had the potential to heal.

Anatomical and functional results after arthroscopic Hill-Sachs remplissage.

BACKGROUND Large osseous defects of the posterosuperior aspect of the humeral head can engage the glenoid rim and cause recurrent instability after arthroscopic Bankart repair for glenohumeral dislocation. Filling of the humeral head defect with the posterior aspect of the capsule and the infraspinatus tendon (i.e., Hill-Sachs remplissage) has recently been proposed as an additional arthroscopic procedure. Our hypothesis is that the capsulotenodesis heals in the humeral bone defect without a severe adverse effect on shoulder mobility, allowing return to preinjury sports activity. METHODS Of 459 patients operated on for recurrent traumatic anterior shoulder instability, forty-seven (10.2%) underwent arthroscopic Bankart repair combined with Hill-Sachs remplissage with use of suture anchors. All had a large Hill-Sachs lesion (Calandra grade III), engaging over the glenoid rim, without substantial glenoid bone loss. Nine patients had had prior unsuccessful surgery to address glenohumeral instability (three Bankart and six Bristow-Latarjet procedures). The average age at the time of surgery (and standard deviation) was 29 ± 5.4 years. Postoperatively, comparative shoulder motion was precisely measured with use of digital photographic images. Capsulotenodesis healing was assessed on a computed tomography (CT) arthrogram (n = 38) or magnetic resonance image (MRI) (n = 4). The mean duration of follow-up was twenty-four months. RESULTS Healing of the posterior aspect of the capsule and the infraspinatus tendon into the humeral defect was observed in all forty-two patients who underwent postoperative imaging, and thirty-one (74%) had a remplissage of ≥75%. Compared with the normal (contralateral) side, the mean deficit in external rotation was 8° ± 7° with the arm at the side of the trunk and 9° ± 7° in abduction at the time of the last follow-up. Of forty-one patients involved in sports, thirty-seven (90%) were able to return postoperatively and twenty-eight (68%) returned to the same level of sports, including those involving overhead activities. Ninety-eight percent (forty-six) of the forty-seven patients had a stable shoulder at the time of the last follow-up. CONCLUSIONS Arthroscopic Hill-Sachs remplissage, performed in combination with a Bankart repair, is a potential solution for patients with a large engaging humeral head bone defect but no substantial glenoid bone loss. The posterior capsulotenodesis heals predictably in the humeral defect. The slight restriction in external rotation (approximately 10°) does not significantly affect return to sports, including those involving overhead activities. The procedure, which may also be useful for revision of previous failed glenohumeral instability surgery, is not indicated for patients with glenoid bone deficiency.

Impact of Fatty Infiltration of the Teres Minor Muscle on the Outcome of Reverse Total Shoulder Arthroplasty

BACKGROUND Reports have demonstrated that reverse shoulder arthroplasty restores overhead elevation but fails to restore active external rotation. The teres minor muscle-tendon unit contributes to active external rotation, and its deficiency may impair the clinical outcome. It was therefore the purpose of this study to evaluate the influence of fatty infiltration of the teres minor muscle on the clinical outcome after reverse total shoulder replacement. METHODS Forty-two shoulders in forty-two patients (average age, seventy-one years) with painful cuff tear arthropathy or an irreparable rotator cuff deficiency with pseudoparesis were treated with a reverse Delta-III shoulder arthroplasty and followed clinically for a minimum of twenty-four months. Preoperatively, fatty infiltration of the teres minor was assessed, according to the grading system of Goutallier et al., with use of magnetic resonance imaging. The effect of teres minor fatty infiltration on the subjective and objective outcomes of the reverse shoulder arthroplasty was evaluated. RESULTS The thirty shoulders with stage-0, 1, or 2 fatty infiltration of the teres minor muscle (group 1) had a significantly better ultimate Constant score, a significantly better subjective shoulder value, and significantly greater preoperative-to-postoperative improvement than the twelve shoulders with stage-3 or 4 fatty infiltration (group 2). In group 1 the relative Constant score increased by an average of 41% and the subjective shoulder value increased by an average of 44%, whereas in group 2 the respective increases were 32% (p = 0.033) and 25% (p = 0.018). Group 1 had an average increase of 6.2 points in the score for extremity positioning, whereas group 2 gained only 5.3 points (p = 0.033). Group 1 had a net gain of 9 degrees of external rotation with the arm at the side compared with an average net loss of 7 degrees in group 2 (p < 0.001). CONCLUSIONS Stage-3 or 4 fatty infiltration of the teres minor compromises the clinical outcome of reverse shoulder arthroplasty for the treatment of irreparable rotator cuff tears.

Subscapularis Muscle Function and Structure After Total Shoulder Replacement with Lesser Tuberosity Osteotomy and Repair

BACKGROUND Recent studies have suggested that tenotomy and repair of the subscapularis tendon carried out for anterior approaches to the shoulder can be followed by failure of the tendon repair and by changes resulting in permanent loss of subscapularis function. We hypothesized that release of the subscapularis with use of a superficial osteotomy of the lesser tuberosity followed by repair of the two opposing bone surfaces would lead to consistent bone-to-bone healing, which would be possible to monitor radiographically, and would lead to satisfactory clinical and structural outcomes. METHODS Thirty-nine shoulders in thirty-six consecutive patients who, at an average age of fifty-seven years, had undergone total shoulder replacement through an anterior approach involving an osteotomy of the lesser tuberosity were evaluated at an average of thirty-nine months. Assessment included a standardized interview and physical examination, scoring according to the system described by Constant and Murley, and imaging with conventional radiography and computed tomography to assess healing of the osteotomy site and changes in the subscapularis. RESULTS The osteotomized tuberosity fragment healed in an anatomical position in all shoulders, and no cuff tendon ruptures were observed. At the time of follow-up, thirty-three (89%) of thirty-seven shoulders evaluated with a belly-press test had a negative result and twenty-seven (75%) of thirty-six shoulders evaluated with a lift-off test had an unequivocally normal result. Fatty infiltration of the subscapularis muscle increased after the operation (p < 0.0001) and was at least stage two in eleven (32%) of thirty-four shoulders. The fatty infiltration had progressed by one stage in eight (24%) of the thirty-four shoulders, by two stages in five shoulders (15%), and by three stages in two shoulders (6%). CONCLUSIONS Osteotomy of the lesser tuberosity provides an easy anterior approach for total shoulder replacement and is followed by consistent bone-to-bone healing, which can be monitored, and good subscapularis function. In the presence of documented anatomical healing of the osteotomy site, postoperative fatty infiltration of the subscapularis muscle remains unexplained and needs to be investigated further as it is associated with a poorer clinical outcome.

Neer Award 2007: Reversion of structural muscle changes caused by chronic rotator cuff tears using continuous musculotendinous traction. An experimental study in sheep

HYPOTHESIS Chronic rotator cuff tears are associated with irreversible architectural muscle changes and a high rate of repair failure. The changes observed in man and their irreversibility with a single stage repair can be reproduced in sheep. It was the purpose of this experiment to test the hypothesis that slow, continuous elongation of a retracted musculotendinous unit allows reversal of the currently irreversible structural muscle changes. MATERIALS AND METHODS The infraspinatus tendon of 12 sheep was released using a greater tuberosity osteotomy and allowed to retract for 4 months. Then, a new device was mounted on the scapular spine and used to extend the infraspinatus muscuculotendinous unit transcutaneously by 1 mm per day. Thereafter, the tendon was repaired back to the greater tuberosity. We assessed the muscular architecture using magnetic resonance imaging, macroscopic dissection, histology, and electron microscopy. Fatty infiltration (in Hounsfield units 1/4 HU) and muscular cross-sectional area (in % of the control side) were monitored with computed tomography at tendon release, initiation of elongation, repair, and at sacrifice. RESULTS Sixteen weeks after tendon release, the mean tendon retraction was 29 +/- 6 mm (14% of original length, P = .008). In 8 sheep, elongation was achieved as planned (group I), but in 4, the elongation failed technically (group II). The mean traction time was 24 +/- 6 days with a mean traction distance of 19 +/- 4 mm. At sacrifice, the mean pennation angle in the infraspinatus of group I was not different from the control side (29.8 degrees +/-7.5 degrees vs. 30 degrees +/-6 degrees , P = .575). In group II, the pennation angle had increased from 30 degrees +/-6 degrees to 55 degrees +/-14 degrees (P = .035). There was no fatty infiltration at the time of tendon release. After retraction, there was a significant increase in fatty infiltration of the infraspinatus muscle and a decrease of its cross-sectional area to 57% of the contralateral side (P = .0001). During traction, the degree of fatty infiltration remained unchanged (36 HU to 38 HU, P = .381), and atrophy improved to a muscle square area of 78% of the contralateral side (P = .0001) in group I. In group II, an increase of fatty infiltration was measured from 36 HU to 28 HU; however, this increase was not significant (P = .144). Atrophy did not change in group II (57-55%, P = .946). At sacrifice, the remaining muscle mass was 64% in group I and 46% in group II (P = .019). DISCUSSION Our preliminary results document, that continuous elongation of a retracted, fatty infiltrated and atrophied musculotendinous unit is technically feasible. CONCLUSION In the sheep, continuous elongation can lead to restoration of normal muscle architecture, to partial reversal of muscle atrophy, and to arrest of the progression of fatty infiltration. LEVEL OF EVIDENCE Basic science level 2; Prospective comparative therapeutic study.

Lesser tuberosity osteotomy for total shoulder arthroplasty. Surgical technique

BACKGROUND Recent studies have suggested that tenotomy and repair of the subscapularis tendon carried out for anterior approaches to the shoulder can be followed by failure of the tendon repair and by changes resulting in permanent loss of subscapularis function. We hypothesized that release of the subscapularis with use of a superficial osteotomy of the lesser tuberosity followed by repair of the two opposing bone surfaces would lead to consistent bone-to-bone healing, which would be possible to monitor radiographically, and would lead to satisfactory clinical and structural outcomes. METHODS Thirty-nine shoulders in thirty-six consecutive patients who, at an average age of fifty-seven years, had undergone total shoulder replacement through an anterior approach involving an osteotomy of the lesser tuberosity were evaluated at an average of thirty-nine months. Assessment included a standardized interview and physical examination, scoring according to the system described by Constant and Murley, and imaging with conventional radiography and computed tomography to assess healing of the osteotomy site and changes in the subscapularis. RESULTS The osteotomized tuberosity fragment healed in an anatomical position in all shoulders, and no cuff tendon ruptures were observed. At the time of follow-up, thirty-three (89%) of thirty-seven shoulders evaluated with a belly-press test had a negative result and twenty-seven (75%) of thirty-six shoulders evaluated with a lift-off test had an unequivocally normal result. Fatty infiltration of the subscapularis muscle increased after the operation (p < 0.0001) and was at least stage two in eleven (32%) of thirty-four shoulders. The fatty infiltration had progressed by one stage in eight (24%) of the thirty-four shoulders, by two stages in five shoulders (15%), and by three stages in two shoulders (6%). CONCLUSIONS Osteotomy of the lesser tuberosity provides an easy anterior approach for total shoulder replacement and is followed by consistent bone-to-bone healing, which can be monitored, and good subscapularis function. In the presence of documented anatomical healing of the osteotomy site, postoperative fatty infiltration of the subscapularis muscle remains unexplained and needs to be investigated further as it is associated with a poorer clinical outcome.

Adipogenic and myogenic gene expression in rotator cuff muscle of the sheep after tendon tear.

Chronic rotator cuff tendon tears lead to fatty infiltration and muscle atrophy with impaired physiological functions of the affected muscles. However, the cellular and molecular mechanisms of corresponding pathophysiological processes remain unknown. The purpose of this study was to characterize the expression pattern of adipogenic (PPARγ, C/EBPβ) and myogenic (myostatin, myogenin, Myf‐5) transcription factors in infraspinatus muscle of sheep after tenotomy, implantation of a tension device, refixation of the tendon, and rehabilitation, reflecting a model of chronic rotator cuff tears. In contrast to human patients, the presented sheep model allows a temporal evaluation of the expression of a given marker in the same individual over time. Semiquantitative RT/PCR analysis of PPARγã, myostatin, myogenin, Myf‐5, and C/EBPβ transcript levels was carried out with sheep muscle biopsy‐derived total RNA. We found a significantly increased expression of Myf‐5 and PPARγ after tenotomy and a significant change for Myf‐5 and C/EBPβ after continuous traction and refixation. This experimental sheep model allows the molecular analysis of pathomechanisms of muscular changes after rotator cuff tear. The results point to a crucial role of the transcription factors PPARγ, C/EBPβ, and Myf‐5 in impairment and regeneration of rotator cuff muscles after tendon tears in sheep.