再手術を要した膝蓋骨不安定症の検討

Revision Surgery for the Patellar Instability

　抄録：膝蓋骨不安定症の病態には多くの因子が関与するとされ，治療法も多岐にわたる．今回，膝蓋骨不安定症の成績不良例に対する再手術の治療成績を検討したので報告する．症例は過去6年間に手術を行った膝蓋骨不安定症症例52例74膝のうち，再手術を要した3例3膝と，他医で初回手術を受け，成績不良であった3例3膝の計6例6膝である．再手術の原因は再脱臼1例，亜脱臼1例，apprehension signの残存と膝前面痛4例であった．初回手術の内訳はElmslie-Trillat法3例，外側膝蓋支帯解離術（LRR）を併用しないFulkerson法1例，LRRと内側膝蓋支帯縫縮術を併用したもの1例，内側膝蓋支帯縫縮術1例であった．再手術方法は外側膝蓋支帯解離術を併用したFulkerson法を4例に行い，2例には内側支持機構再建術（Avikainen法）を行った．再手術後の経過は比較的良好であったが，治療成績不良因子として膝蓋骨高位，全身関節弛緩に伴う膝蓋骨過可動性，膝蓋大腿関節の関節症性変化が考えられた．

　The pathophysiology of the patellar instability varies and consists of the combination of morphological, biomechanical and neuromuscular factors. Therefore, numerous treatment procedures have been reported and the suitable procedure is chosen depending on major pathological component. However, there were few reports on the revision surgery for the patients with failed primary surgery. The purpose of this study was to investigate the risk factors of failed surgery and results of the revision surgery for the residual patellar instability. Seventy-seven knees in 55 cases were operatively treated in our institution in past 6 years. The revision surgery was performed in 6 knees due to patellar dislocation (1 knee), patellar subluxation (1 knee) and patellar apprehension with anterior knee pain (4 knees). The initial surgeries for the 6 knees were Elmslie-Trillat procedure (3 cases), anteromedialization of the tibial tuberosity (Fulkerson procedure) (1 case), lateral retinacular release alone (1case) and lateral retinacular release combined with medial retinacular plication (1 case). The procedures of the revision surgery were Fulkerson procedure combined with lateral retinacular release and adductor magnus tenodesis (Avikainen procedure). The factors that contribute to the poor outcome of primary surgery were patellar alta, patellar hyper mobility accompanied with general joint laxity and osteoarthritic changes of the patellofemoral joint.