Aim. To identify and quantify the reasons for failure of primary shoulder arthroplasty.

Materials. Seventy-nine Revision Shoulder Arthroplasties (RSA) in 75 patients were performed between January 1990 and July 2003. Twelve patients underwent more than one revision. Five patients were lost to follow-up. The indications for PSA (38 total shoulder arthroplasties, 37 hemiarthroplasties) were trauma (22), osteoarthritis (13), rheumatoid arthritis (11), avascular necrosis (9), cuff tear arthropathy (9), traumatic arthritis (5), capsulorraphy arthropathy (4),and instability (2). Glenoid and humeral bone stock, and rotator cuff integrity were analysed and the reasons for failure of the index procedure were determined.

Results. The median interval between PSA and RSA was 46 months (1 month to 22.8 years; mean 28 months). Thirty-six (58.1%) PSAs (of which 26 of 37 hemiarthroplasties (70%)) failed in the first three years. Failure of the PSA was caused by rotator cuff deficiency (24), glenoid bone erosion (19), glenoid component loosening (25), humeral bone erosion (3), infection of the implant (3) and periprosthetic fracture (1). Revision of a loose humeral component was performed in 6 cases, but 31 humeral components were revised in order to deal with glenoid or rotator cuff conditions.

Conclusion. When faced with a limited surgical armamentarium or tactic, there is a predictable rate of failure of shoulder replacement involving the interaction of the failed or failing rotator cuff and the evolution of glenoid deficiency.

Aim: To evaluate the role and outcome of FFTSA in shoulders with arthritis and/or irreparable rotator cuff tears.

Materials. The records of 60 consecutive patients with FFTSA were retrospectively reviewed. Primary FFTSA (group 1) was performed in 29 (48%), revision FFTSA (group 2) in 26 (43%), and re-revision FFTSA (group 3) in 5 (9%) patients. The mean age at primary FFTSA was 70 years (37 – 82), and at revision FFTSA, 67.6 years (38 – 89) at a mean interval of 38 months after primary intervention. In re-revision FFTSA the interval between the primary (mean age 64 years) and final (mean age 68.4 years) interventions varied from 20 to 148 months. Primary FFTSA was performed for cuff arthropathy in 18 (62%) and after trauma in 5 (17%): all 29 patients had rotator cuff insufficiency. Revision FFTSA was performed for failure of humeral head replacement (HHR) after fracture in 17 (65%) of which 14 had rotator cuff insufficiency. All those in group 3 had rotator cuff insufficiency. The dominant indication for intervention was pain in 59 cases. The glenoid component was uncemented in all cases. The humeral component was cemented in 27 of the 29 Primary FFTSA. CADCAM variations of the standard humeral design were used in 8 cases.

Results. At a mean follow-up of 25 months, 81% of primary FFTSA had no or mild pain, and 87.5% were satisfied or very satisfied with the outcome: both outcomes were independent of the original rotator cuff defect. At a mean follow-up of 41 months, 69% of revision FFTSA had no or mild pain, and 68 % were satisfied or very satisfied: the least satisfied patients were those in which a previous HHR for fracture had been the primary intervention. There were 3 complications in group 1, 2 in group 2, and 2 in group 3. In 4 patients with deficient deltoid function, 3 were satisfied with the eventual outcome

Conclusion. FFTSA has a clear role in the management of shoulders in which the rotator cuff has failed and a joint replacement is required for pain relief.

Aim: To demonstrate that inappropriate sequencing of activation of shoulder muscles can cause shoulder instability.

Methods. The records of 933 cases of recurrent shoulder instability referred to a specialist shoulder service between 1993 and 2003 were reviewed. All patients were assessed clinically. Muscle patterning abnormality (Bayley 1986) was identified in 428 patients (46%). Confirmatory functional electromyography was performed in 166 (36%). Inappropriate pectoralis major activation was identified in 73% of anterior instability. In posterior instability, inappropriate activation of latissimus dorsi and anterior deltoid was present in 72% and infra-spinatus was suppressed in 19%. Arthroscopic assessment was performed in 141 (33%), identifying structural lesions of instability in 86 (20%).

All patients diagnosed with muscle patterning disorder received specilalist physical therapy using biofeedback. Symptomatic improvement or stability was achieved in 76% of patients with anterior instability but with no previous surgery, and in 53% of patients with previous surgery. Posterior instability was eliminated in 85% of cases.

Conclusion. Muscle patterning abnormalities contribute to recurrent instability of the shoulder in 46% of cases. The success of physical therapy in these patients is high.