Edward V. Craig

Cuff-tear arthropathy.

In this report we describe the clinical and pathological findings of cuff-tear arthropathy in twenty-six patients and discuss the differential diagnosis and a hypothesis on the pathomechanics that lead to its development. This lesion is thought to be peculiar to the glenohumeral joint because of the unique anatomy of the rotator cuff. Following a massive tear of the rotator cuff there is inactivity and disuse of the shoulder, leaking of the synovial fluid, and instability of the humeral head. These events in turn result in both nutritional and mechanical factors that cause atrophy of the glenohumeral articular cartilage and osteoporosis of the subchondral bone of the humeral head. A massive tear also allows the humeral head to be displaced upward, causing subacromial impingement that in time erodes the anterior portion of the acromion and the acromioclavicular joint. Eventually the soft, atrophic head collapses, producing the complete syndrome of cuff-tear arthropathy. The incongruous head may eventually erode the glenoid so deeply that the coracoid becomes eroded as well. Although treatment of cuff-tear arthropathy is extremely difficult, the preferred method appears to be a resurfacing total shoulder replacement with rotator-cuff reconstruction and special rehabilitation. We think that it is important to recognize cuff-tear arthropathy as a distinct pathological entity, as such recognition enhances our understanding of the more common impingement lesions. Cuff-tear arthropathy is especially difficult to treat, and although many tears of the rotator cuff do not enlarge sufficiently to allow this condition to develop, it is a factor to consider when deciding whether or not a documented tear of the rotator cuff should be surgically repaired.

Propionibacterium acnes infection after shoulder arthroplasty: a diagnostic challenge.

HYPOTHESIS This study reviewed a series of patients diagnosed with Propionibacterium acnes infection after shoulder arthroplasty in order to describe its clinical presentation, the means of diagnosis, and provide options for treatment. MATERIALS AND METHODS From 2002 to 2006, 11 patients diagnosed with P acnes infection after shoulder arthroplasty were retrospectively reviewed and analyzed for (1) clinical diagnosis; (2) laboratory data, including white blood cell count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP); (3) fever; (4) number of days for laboratory growth of P acnes; (5) organism sensitivities; (6) antibiotic regimen and length of treatment; and (7) surgical management. Infection was diagnosed by 2 positive cultures. RESULTS Five patients had an initial diagnosis of infection and underwent implant removal, placement of an antibiotic spacer, and staged reimplantation after a course of intravenous antibiotics. In the remaining 6 patients, surgical treatment varied according to the clinical diagnosis. When infection was recognized by intraoperative cultures, antibiotics were initiated. The average initial ESR and CRP values were 33 mm/h and 2 mg/dL, respectively. The average number of days from collection to a positive culture was 9. All cultures were sensitive to penicillin and clindamycin and universally resistant to metronidazole. DISCUSSION Prosthetic joint infection secondary to P acnes is relatively rare; yet, when present, is an important cause of clinical implant failure. Successful treatment is hampered because clinical findings may be subtle, many of the traditional signs of infection are not present, and cultures may not be positive for as long as 2 weeks.

Arthroscopic Treatment of Partial Rotator Cuff Tears in Young Athletes A Preliminary Report

Forty-three athletes under age 40, more than half of which were collegiate or professional, with partial rota tor cuff tears were treated arthroscopically and ob served for a minimum of 24 months. By history and mechanism of injury, two main groups were identified. Group A had 14 patients with acute, traumatic injuries. All 14 had inflamed subacromial bursas, but increased glenohumeral translation and labral lesions were un common. Twelve patients (86%) had satisfactory post operative results and nine (64%) returned to preinjury sports after arthroscopic subacromial decompression and tear debridement. Group B had 29 overhead ath letes with insidious, atraumatic shoulder pain. They were not as successful with debridement (19 [66%] satisfactory and 13 [45%] return to preinjury sports). Within Group B, three subgroups were identified based on the examination under anesthesia and subacromial inflammation. Group B1 (8 patients) had normal-ap pearing subacromial spaces and often increased ante rior glenohumeral translation with posterior labral tears. These patients did poorly after arthroscopic tear debridement (3 [38%] satisfactory and 2 [25%] return to sports). Group B2 (12 patients) had inflamed sub acromial bursas and increased glenohumeral transla tion. This group had marginal results with debridement (7 [58%] satisfactory and 6 [50%] return to sports). Group B3 (9 patients) with subacromial inflammation, yet without increased glenohumeral translation, had excellent pain relief (100%) but less than half (4) re turned to preinjury sports.

Biomechanics of massive rotator cuff tears: implications for treatment.

BACKGROUND Some individuals with massive rotator cuff tears maintain active shoulder abduction, and some maintain good postoperative active range of motion despite high rates of repeat tears after repair. We devised a biomechanical rationale for these observations and measured the increases in residual muscle forces necessary to maintain active shoulder motion with rotator cuff tears of various sizes. METHODS A custom cadaver shoulder controller utilizing position and orientation closed-loop feedback control was used. Six cadaver glenohumeral joint specimens were tested in open-chain scapular plane abduction with equivalent upper extremity weight. The shoulder controller limited superior translation of the humeral head to 3.0 mm while maintaining neutral axial rotation by automatically controlling individual rotator cuff forces. Three-dimensional position and orientation and rotator cuff and deltoid force vectors were recorded. Specimens were tested with an intact rotator cuff and with 6, 7, and 8-cm tears. RESULTS All six specimens achieved full abduction with <or=3.0 mm of superior translation of the humeral head for all rotator cuff tear sizes. The effect of rotator cuff tear was significant for all tear sizes (p < 0.01). Compared with the intact condition, the subscapularis force requirements for the 6, 7, and 8-cm tears were increased by 30%, 44%, and 85%, respectively. For the combined infraspinatus and teres minor, the forces were increased by 32%, 45%, and 86%, respectively. The maximum deltoid force for the simulated tear condition never exceeded the deltoid force required at maximum abduction for the intact condition. However, between 10 degrees and 45 degrees of abduction, the average deltoid force requirement increased 22%, 28%, and 45% for the three tear sizes. CONCLUSIONS In the presence of a massive rotator cuff tear, stable glenohumeral abduction without excessive superior humeral head translation requires significantly higher forces in the remaining intact portion of the rotator cuff. These force increases are within the physiologic range of rotator cuff muscles for 6-cm tears and most 7-cm tears. Increases in deltoid force requirements occur in early abduction; however, greater relative increases are required of the rotator cuff, especially in the presence of larger rotator cuff tears.

The Combined Dynamic and Static Contributions to Subacromial Impingement A Biomechanical Analysis

Ten human cadaveric shoulders were tested with a dynamic shoulder model simulating physiologic rotator cuff, deltoid, and biceps muscle forces. The combined effect of the muscle forces and acromial structure on subacromial impingement was measured with mini mally invasive, miniature pressure transducers. Shoul ders with large acromial spurs had significantly greater impingement pressures at the anterolateral acromion in neutral, internal, and external rotation compared with those with flatter acromia. Application of a biceps mus cle force reduced anterolateral acromial pressures by 10%. Failure to simulate a supraspinatus force de creased acromial pressure 52% in shoulders with type III acromia in neutral rotation. Without rotator cuff forces applied, the maximum deltoid muscle force re quired to elevate the arm increased by 17%. Acromial pressures were increased when no rotator cuff forces were applied, but the increases were not significant. After an anterior acromioplasty, pressures decreased by 99% anteriorly. However, failure to achieve a flat surface posteriorly increased pressures in this location, especially with the shoulder in external rotation. Mod eling the rotator cuff and deltoid muscle forces dem onstrated the importance of the muscular force couple to center the humeral head during elevation of the arm. The inferior forces of the infraspinatus, teres minor, and subscapularis muscles were necessary to neutral ize the superior shear force produced by the deltoid and supraspinatus muscles.

Risk factors for early failure after thermal capsulorrhaphy.

Thermal capsular shrinkage has rapidly become a common procedure for a variety of shoulder conditions usually associated with instability, although clinical data on outcomes are limited. The objective of this study was to identify risk factors for poor outcome after thermal capsulorrhaphy. Of 106 patients who underwent thermal shrinkage, 15 patients with treatment failures were identified. The mean time to failure after the procedure was 6.3 months (range, 1 to 16). Previous operations and multiple recurrent dislocations were associated with poor outcome at a highly significant level. Multidirectional instability and participation in contact sports did not attain statistical significance as risk factors. However, statistical power in these two comparisons was insufficient to exclude them as potential risk factors. A concomitant procedure at the time of thermal capsulorrhaphy was not associated with poor outcome. The data from early treatment failures can be useful in guiding patient selection for thermal capsulorrhaphy. This procedure may be of limited value for patients who have had prior operations or have a history of multiple dislocations. The data also suggest that thermal capsulorrhaphy should be used cautiously in patients with multidirectional instability or in those who are involved in contact sports.

Cuff tear arthropathy: current trends in diagnosis and surgical management.

SUMMARY Massive tears of the rotator cuff resulting in arthritis of the glenohumeral joint remain a difficult challenge. Although cuff tear arthropathy (CTA) has been recognized for more than 150 years, a treatment strategy with uniformly satisfactory outcomes remains elusive, partly due to the difficulty in defining CTA in the literature. Most studies combine true CTA, rheumatoid arthritis, and massive rotator cuff tears under the CTA diagnosis. Determining outcomes from these studies is difficult. Hemiarthroplasty and total shoulder arthroplasty have led to pain relief, but the high rate of glenoid component loosening after total shoulder arthroplasty is a concern, and active range of motion remains limited after hemiarthroplasty. There is increasing interest in the use of a constrained or reverese total shoulder arthroplasty to treat this complex process, with promising early results. This review article studies current trends in the diagnosis and management of arthritis due to massive cuff tears and CTA.

Deep vein thrombosis after reconstructive shoulder arthroplasty: a prospective observational study.

This clinical study was performed to document the prevalence of deep vein thrombosis (DVT) after prosthetic shoulder replacement surgery. We prospectively followed 100 consecutive shoulder arthroplasty procedures (total shoulder replacement in 73 and hemiarthroplasty in 27) in 44 male and 56 female patients for 12 weeks (mean age, 67 years; range, 17-88 years). Risk factors for venous thromboembolic disease were assessed preoperatively and postoperatively. A 4-limb surveillance color flow Doppler ultrasound was performed at 2 days (100 patients) and 12 weeks (50 patients randomly selected) after surgery, and the presence and location of DVT were recorded. Postoperative symptomatic or fatal pulmonary emboli (PE) were also recorded. The overall prevalence of DVT was 13.0%, consisting of 13 DVTs in 12 patients. These included 6 ipsilateral and no contralateral upper extremity DVTs and 5 ipsilateral and 2 contralateral lower extremity DVTs. The prevalence of DVT was 10.0% (10/100) at day 2 after surgery and 6.0% (3/50) at week 12 after surgery. The incidence of symptomatic nonfatal PE was 2.0% (2/100), and that of fatal PE was 1.0% (1/100). Risk factors associated with venous thromboembolic disease did not reach statistical significance because of the small study population sample size. At our institution, the prevalence of DVT after reconstructive shoulder arthroplasty was 13.0%, a rate comparable to that after hip arthroplasty (10.3%) but lower than that after knee arthroplasty (27.2%). Shoulder arthroplasty surgeons should be aware of the potential risk of perioperative thromboembolic complications in both the acute and subacute postoperative periods.

Humeral component retroversion in reverse total shoulder arthroplasty: a biomechanical study

BACKGROUND Reverse total shoulder arthroplasty offers pain relief and functional improvement for patients with rotator cuff-deficient shoulders. The purpose of this study was to determine the optimal amount of humeral retroversion for this prosthesis. MATERIALS AND METHODS Six cadaveric shoulders underwent computed tomography (CT) imaging and were then dissected of soft tissues, except for their tendinous attachments. A reverse total shoulder arthroplasty was implanted in 0°, 20°, 30°, and 40° of retroversion, and the shoulders were mounted on a simulator to determine the muscle forces required to achieve 30° and 60° of scaption. CT images were converted into 3-dimensional models, and the amount of internal and external rotation was determined with computer modeling at various scaption angles. RESULTS No differences were found in the forces required for 30° or 60° of scaption for any muscle, at any retroversion. With increasing retroversion, more impingement-free external rotation was obtained, with a concomitant decrease in the amount of internal rotation. Above 60°, the humerus was allowed to rotate around the glenosphere unencumbered. CONCLUSIONS Increasing retroversion did not affect the muscle force requirements for scaption across the shoulder. Placing the humeral component in 0° to 20° of retroversion allows maximum internal rotation with the arm at the side, a movement that is required for daily activities. This limits external rotation with the arm at the side, but has no effect on external rotation with the arm elevated.

The acromioclavicular joint cyst: an unusual presentation of a rotator cuff tear

An unusual presentation of a full-thickness tear of the rotator cuff is the acromioclavicular (AC) joint cyst. This is formed when glenohumeral joint fluid leaks through the full-thickness cuff tear and into a diseased AC joint, eventually distending the superior capsule. Often, communication between the cyst and the glenohumeral joint can be demonstrated on shoulder arthrogram. It is essential to recognize that the presenting cyst is usually indicative of an underlying full-thickness rotator cuff tear, which is often massive and which will be difficult to reconstruct. This clinical finding is reported in the following two cases to emphasize the important relation between AC joint disease and rotator cuff abnormalities. Attempted excision of this cyst without recognition of its pathogenesis usually leads to cyst recurrence and unimproved symptoms.