Abstract
Human bone morphogenetic protein (hBMP) was prepared according to a modified method (Sampath et al). Implants were prepared with 500 μg of hBMP adsorbed onto a composite matrix (1 gm of insoluble collagenous bone matrix and 200 mg of lyophilised human gelatine).
The hBMP/collagen composite was used to treat 11 women and 23 men (mean age 36 years). All patients had failed to achieve union despite previous treatment by internal or external fixation, immobilisation in a cast, and/or allogenic or autogenic bone grafting. The mean age of the nonunions was 26 months (1 to 228).
At surgery a mean of 2 gm per patient of the composite was inserted at the site of the defect, which was stabilised by internal or external fixation. Supplementary allogenic cancellous bone particles and block configured spongy bone was used in 17 patients. At follow-up 1, 8, 16 and 23 weeks postoperatively, functional results were assessed according to weight-bearing. A score of 0 was given where there was no weight-bearing, a score of 1 for weight-bearing with the assistance of two crutches, 2 for light weight-bearing with one crutch, 3 for full weight-bearing with one crutch and 4 for full weight-bearing without crutches. At a mean follow-up of 17 weeks (8 to 32), the mean score was 3.25, higher than the mean preoperative score of 2.22 and mean one-week follow-up score of 0.5. Of the five patients who suffered recurrent infection, two failed to score above 2 at 17 weeks mean.
Present results indicate that hBMP composite implants may represent effective treatment of difficult nonunions.
The abstracts were edited by Prof. M.B.E. Sweet. Correspondence should be addressed to him at the Department of Orthopaedic Surgery, Medical School, University of the Witwatersrand, 7 York Road, Parktown, 2193 South Africa
