小児期受傷の成人上腕骨外顆偽関節に対する骨接合術

Osteosynthesis for Longstanding Nonunion of Lateral Humeral Condyle

　長期経過した成人上腕骨外顆偽関節に対して骨接合術を行った5例を評価し，その功罪につき検討した．受傷時年齢は平均7歳で，手術時年齢は平均44.6歳．術前の症状は尺骨神経症状のみが2例，尺骨神経症状と疼痛が2例，疼痛のみが1例であった．術前可動域は伸展平均－15°，屈曲平均132°で，Tohらによる上腕骨外顆偽関節のX線像分類でgroup 1が1例，group 2が4例であった．最大屈伸側面X線像にて外顆骨片の動きを計測し偽関節部での動きとしたところ平均27°であったが，この角度を骨接合術後に生じる可動域制限と予想した．手術は後方からアプローチし，まず尺骨神経を剝離し，皮下前方移行する．次にK-wireで骨片を仮固定し，屈曲を犠牲にしない可動域を確認後，腸骨移植を併用して螺子もしくはプレートを用いて固定した．術後は平均5.5週の外固定を行った．Group 1の1例は骨癒合が得られなかったが，group 2の4例は骨癒合を得た．疼痛を認めた症例は全例骨癒合により症状は消失し，尺骨神経症状も全例で改善した．骨癒合を得た4例とも可動域の減少を認め，総可動域は術前に比べて平均20°の減少を認めた．ただし，術後実際に生じた可動域制限は，術前X線像により予測した可動域制限より平均7°少なく，疼痛を有する上腕骨外顆偽関節group 2は骨接合術の適応と考えられる．

　We evaluated the results of longstanding nonunion osteosynthesis of the lateral humeral condyle in five adults. Surgery was done at an average age of 44.6 years. Two patients had had only ulnar nerve dysfunction, one only pain, and two both. The preoperative range of flexion was 132° and the preoperative range of extension was －15°. One patient was categorized as Group 1 and four as Group 2 in radiography. We evaluated the mobility of the fragment by tilting the angle of lateral view in maximum flexion and extension radiography. Average mobility was 27° and was considered loss of range of motion. In surgery, the ulnar nerve was transposed anteriorly and osteosynthesis was done using an iliac bone graft. The lateral condyle fragment was positioned to prevent loss of flexion range. A long cast was worn postoperatively for an average of 5.5 weeks. Osseous union was achieved in four Group 2 patients. The remaining Group 1 patient fell into nonunion. Pain disappeared and ulnar nerve symptoms improved in all cases. In the four union patients, total arc was reduced an average of 20° postoperatively. In all patients, postoperative loss of arc was smaller than that expected preoperatively by mobility of the fragment in radiography. The postoperative flexion range was maintained at over 125° in all union cases except for one patient whose lateral condyle fragment was fixed in an extended position. In adults, osteosynthesis is indicated for longstanding painful nonunion of the lateral humeral condyle in Group 2 patients. The lateral condyle fragment must be fixed to prevent loss of flexion range.