悪性骨腫瘍関節外切除後の腫瘍用人工膝関節と腓腹筋弁による膝関節再建

Knee Reconstruction with a Prosthesis and Gastrocnemius Muscle Flap after Extra-articular Resection of Malignant Bone Tumors

　抄録：膝周辺悪性骨腫瘍4例を膝蓋骨半割により関節外切除し，腫瘍用人工膝関節・膝蓋骨表面置換，腓腹筋弁により再建した．発生部位は大腿骨遠位部3例，けい骨近位部1例である．術後合併症は腓骨神経麻痺2例，けい骨神経麻痺1例，膝蓋腱断裂1例，下腿皮膚壊死1例であった．膝関節屈曲角度は70～105°，自動伸展不全は0～90°であった．術後患肢機能はMusculoskeletal Tumor Societyの評価法で50～86％であった．腓腹筋弁は膝関節外切除後の人工関節の被覆および膝伸展機構再建に有用であると思われた．

　We used a tumor endoprosthesis and medial gastrocnemius muscle flap to reconstruct the knee after extra-articular resection of malignant bone tumors in four cases. The patella was divided in the coronal plane, and the preserved patella was resurfaced. The tumor was located in the distal femur in three patients and in the proximal tibia in the other patient. All surgical specimens had negative margins. There were no local recurrences, but pulmonary metastasis occurred in one patient. Major complications consisted of peroneal nerve palsy in two patients, tibial nerve palsy in one patient, extensor mechanism rupture in one patient, and skin necrosis in one patient. There were no postoperative infections. The postoperative range of flexion was 70°-105°, and postoperative extension lag was 0°-90°. The postoperative Musculoskeletal Tumor Society scores ranged from 50％to 86％. The gastrocnemius muscle flap was useful for covering the prosthesis and for reconstructing the knee extensor mechanism after extra-articular resection.