MID TO LONG TERM EXPERIENCES WITH THE SECOND GENERATION GLOBAL(TM) SHOULDER PROSTHESIS

Abstract

Background: After Jules-Emile Pean and Neer, unconstrained prosthetic arthroplasty of the shoulder is widely used for glenohumeral osteoarthritis (OA), rheumatoid arthritis (RA) and trauma. While the debate continues over whether humeral head replacement (HHR) or total shoulder arthroplasty (TSR) is better for OA and RA, hemiarthroplasty is preferred in the trauma situation.

Aims: A retrospective review (1993–2000) of 54 patients with the DePuy Global second generation modular shoulder hemiarthroplasty is presented. We highlight the various complications encountered in the longer term and attempt to use our experience to rationalize treatment choice.

Methods: 49 shoulders in 41 patients were available for review. Case records and radiographs were reviewed and clinical assessment carried out. Functional assessment was done using the Constant (CM) and the American Shoulder and Elbow Society systems (ASES). Patients were also asked to complete a shoulder self assessment questionnaire (Insalata, Hospital for Special Surgery).

Results: The pre-op diagnosis was 20 RA, 12 OA, 11 trauma. The mean age was 63.4Yrs. The mean follow up was 6.8Yrs (4–11 Yrs). The mean Constant scores for the 3 groups were 48.1 RA, 46.3 OA, and 56.6 trauma. The mean ASES functional scores were 39.6 RA, 37.5 OA and 32.9 trauma. Active elevation in the RA group was a mean of 83.5°, and 69.5° for OA and 79° for the trauma group. 65% of the RA group was completely pain free compared to 50% and 54% in the OA and trauma groups respectively. Patient satisfaction was high in the RA and OA groups but poor in the trauma group. 90% of RA patients had evidence of superior migration of the prosthesis (ASM), with the majority of them developing cuff dysfunction. 36% of trauma patients had tuberosity escape/nonunion. 100% of OA patients developed late glenoid erosion. Presence of secondary glenoid arthrosis and ASM co-related with poor function (r =0.5, p< 0.05).

Discussion. Second generation prosthesis can prejudice the shoulder biomechanics. Over-tensioning the joint can lead to both glenoid wear and cuff rupture.

In OA patients, satisfaction was highest, but function was poor. Patients with out cuff tear pre-operatively did not develop it later. They may thus benefit from a TSR compared to HHR. RA patients had the least pain, best function and high satisfaction. Most had evidence of either primary or secondary cuff dysfunction. In them patients HHR may be the preferred option. Trauma patients did poorly in all respects. More anatomical reconstruction and greater emphasis on salvage of the humeral head is required in this group.