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To prevent adhesion between the tendon and the plate in hand surgery, a porous poly L-lactide-co-ε-caprolactone (P(LA/CL)) membrane was developed as a biologically absorbable anti-adhesion material. Our study aims to confirm the efficacy of this new P(LA/CL) membrane and its influences on the osteotomy site by performing a fundamental experiment assessing the possibility of clinical application.

We prepared a rabbit model of tendon-plate adhesion, and evaluated the efficacy of the P(LA/CL) membrane to pullout tendon strength, to be scored in terms of macroscopic, pathological results. Another rabbit model of osteotomy was prepared to confirm the P(LA/CL) membrane influences on bone union by radiological, mechanical and pathological evaluation. The result showed to be significantly lower adhesion in the P(LA/CL) membrane group than in the control group. Also there were no differences between the P(LA/CL) membrane group and control group in the results for bone union.

Background: The purpose of this study was to report the results of metaphyseal and diaphyseal ulnar shortening osteotomies (USO) for the treatment of ulnar abutment syndrome (UAS).

Methods: From 2011 to 2016, we performed metaphyseal USO in 8 patients (8 wrists) and diaphyseal USO in 6 patients (7 wrists). The results were investigated in terms of bone union and cast immobilization, wrist and forearm range of motion (ROM). The mean follow-up duration was 29 months.

Results: All 14 patients had bone union. The mean duration of bone union in metaphyseal USO and diaphyseal USO were 3.5 months and 4.3 months and the duration of cast immobilization after surgery were 24.2 days and 29.2 days. The mean forearm ROM (degree) were 134.3 (pronation/supination: 66.7/67.6) and 169.3 (pronation/supination: 84.3/85.0) at 3 months after surgery and 173.4 (pronation/supination: 86.0/87.4) and 172.8 (pronation/supination: 87.1/85.7) at 6 months after surgery.

Conclusions: The results from this study suggest that metaphyseal osteotomies are an effective alternative to diaphyseal osteotomies for the treatment of ulnar abutment syndrome. Although metaphyseal osteotomies were associated with temporary decrease of pronation, this discrepancy resolved at 6 months postoperatively. Metaphyseal USO has the potential to promote primary bone union and appears to be an alternative treatment for UAS.

Radiographic findings of bone union and clinical outcome in AF using HAP was evaluated and Biomechanical study was performed to certify that our method is suitable for AF using HAP. Clinically, 33 patients with myelopathy were investigated. The status of bone union was classified into 4 grades. Grade 1 is nonunion. Grade 2 is probable nonunion. Grade 3 is probable union. Grade 4 is bone union. Surgical outcome was evaluated by Japanese Orthopaedic Association(JOA) score. In biomechanical study, two models was examined. One is Robinson method without removal of end plate. The other is our method with exposure of spongy bone. No case showed grade 1 and 2.12% cases showed grade 3 and 88% grade 4. There was 5 cases with cracks. Those showed no instability and no collapse of HAP. The average preoperative and postoperative JOA score was 11.2 and 14.9 points respectively. Recovery rate was 64%. There was breakage of HAP without sinking of HAP in Robinson method. The compressive strength of breakage of HAP in Robinson method were a half to one third of those in our method. Our method gives us satisfactory clinical outcome and radiographic results, and should be used for AF using HAP.