Clinical Research On Application Of Trephine For Arthrodesis Of The Ankle Via Lateral Approach

Objective To introduce a new technique of ankle arthrodesis with trephine by lateral approach and evaluate its clinical effects. Methods Between October 2000 and February 2005, ankle arthrodesis with trephine was performed in 20 patients with serious lesions. Of these 20 cases, there were 12 males and 8 females with an average age of 41 years(range from 28 to 55 years). The diagnoses included posttraumatic arthritis in 13 cases and degenerative osteoarthritis in 7 cases. Lateral incision was adopted and osteotomy of fibula above the lower tibiofibular joint facilitated the exposure of the fusion site. A trephine of appropriate diameter(Ф14mm,16mm,18mm)was used for bi-osteotomy; thus inside the trephine gaining two bone blocks which were then rotated 90oand replanted in situ. The pruned fibula was fixed with screws as on-lay grafting. Long-leg cast was fixed 6 weeks postoperatively to maintain a functional position, and a further fixation of short-leg walking-cast was utilized for 6 weeks. Results All the 20 cases were available for review, with an average follow-up of 26 months (range from 6 months to 4 years). AOFAS Clinical rating system score increased from 25.9 preoperatively to 88.9 postoperatively and each item including pain, function and alignment were all improved significantly. All the wounds healed well at 2 weeks and the callus appeared 4 weeks postoperatively. Sufficient pain relief was obtained in all patients at 12 weeks and appearance greatly improved. A solid union was achieved in all cases from the radiograph. There were no severe complications; only one case suffered from slightly dropping-foot and one case complained of local discomfort after long time of walking or standing. Conclusions The use of trephine in ankle fusion by lateral approach was proved to be a simple technique with high union rate. The main advantages of the technique over other methods of arthrodesis include: excellent exposure by regular incision; less disturbance of the original joint, thereby preserving normal height of the joint and length of the extremity; no need for extra graft through in-situ grafting of the bone blocks and rigid on-lay grafting of lateral malleolus for high primary stability.