Digital Joint Reconstruction with Osteotendinous Joint Allograft: Experimental Study in Rats.

BACKGROUND: Fresh or frozen nonvascularized osteotendinous joint allografts (OTJA) have not been used previously, clinically or experimentally, for metacarpophalangeal joint reconstruction. Therefore, we evaluated the viability of OTJA for metatarsophalangeal joint (MTJ) reconstruction in rats.

METHODS: In the experimental group of 12 Lewis rats, we reconstructed the MTJ of the third digit of the hindlimb with a fresh, nonvascularized OTJA obtained from the same digit from 12 donor rats. In the control group of 6 Lewis rats, an autologous composite osteotendinous graft of the MTJ of the same digit was obtained and repositioned in situ as an auto-transplant. Weight, pain, edema, dehiscence, and wound infection were evaluated every 24 hours for 30 days postoperatively. At the end of 30 days, we evaluated digit position, flexion and extension, passive mobility, radiological bone healing, and histological grades of rejection.

RESULTS: We found no statistically different changes in weight, edema, pain, digit position, or radiological bone healing in either group. No wound dehiscence or infection was seen in any of the rats. Ten degrees of flexion and extension mobility were lost in the control group; the experimental group lost up to 30 degrees (P = 0.009). Histologically, 9 of the experimental group rats (9/12, 75%) showed rejection reactions compared with none of the controls (0%) (P = 0.009).

CONCLUSIONS: Fresh nonvascularized OTJA caused an immune reaction without exposure of the graft, but with bone resorption. However, the rats maintained digital form and alignment with decreased passive flexion and extension of 10-30 degrees.