ENDOPROSTHETIC REPLACEMENT OF THE PROXIMAL HUMERUS – LONG-TERM FUNCTIONAL ASSESSMENT

Abstract

Reconstruction of the shoulder joint following resection of the proximal humerus for bone tumours remains controversial. We report the long term functional results of the simplest form of reconstruction – an endoprosthesis.

One hundred patients underwent endoprosthetic replacement of the proximal humerus between 1976 and 1998. Thirty eight had osteosarcoma, 17 had chondrosarcoma, 16 had metastases and 9 had Ewing’s sarcoma. Mean age was 36 years (range 10 to 80 yrs). Survivorship of patients and prostheses were calculated. Function was assessed using the Musculoskeletal tumour society (MSTS) and Toronto extremity salvage (TESS) scoring systems. Thirty patients could come to the clinics for MSTS scoring and 38 out of 49 alive patients replied to the TESS questionnaires sent out to them.

The overall survival of the patients was 42% at 10 years. Local recurrence (LR) arose in 16 patients, being most common in chondrosarcoma (26%) and osteosarcoma (22%) and arose in 50% of patients with these tumours who had marginal excisions. Of these 16 patients, 8 had forequarter amputations whilst the remainder had excisions and radiotherapy. Mean time to LR was 12 months and all but two of these 16 patients subsequently died within a mean of 18 months.

The prostheses proved reliable and dependable. Only 9 required further surgery of any sort, 2 needing minor surgery to correct subluxation and 7 needing revisions, one for infection after radiotherapy and six for loosening – three after trauma. The survivorship of the prosthesis without any further surgery was 86. 5% at 20years. The survivorship of the limb without amputation was 93% at 20 years.

The functional outcome was very predictable. Most patients had only 45 degrees of abduction although three patients had normal movements. The mean MSTS functional score was 79% and the mean TESS score was also 79%. There was a high level of patient satisfaction but difficulty was encountered especially in lifting and in all activities above shoulder height. Endoprosthetic replacement of the proximal humerus is a predictable procedure providing reasonable function of the arm below shoulder height. The endoprostheses have proved highly dependable with a low re-operation rate. There is a high risk of local recurrence after inadequate surgery which should be avoided if possible.