Dejour D, Levigne C, Dejour H
Service de Chirurgie Orthopédique, Centre Hospitalier Lyon Sud, Pierre-Bénite-Lyon.
Rev Chir Orthop Reparatrice Appar Mot. 1995;81(4):286-95.
Patella infera is a post operative complication that can be prevented in most cases. This study was undertaken to determine etiological factors and to determine the means to avoid patella infera following knee surgery. The authors describe a new surgical technic to correct this complication and describe prognostic factors for achieving good results.
From 1985 to 1991, 35 patellar tendon lengthenings were performed in 35 patients. There were 28 female and 7 male patients with an average age of 37 years (21 to 72). Follow-up averaged 27 months and all patients had radiographic follow-ups. All patients had previous knee surgery: 21 for patellar pain (= patellar pain), 9 ACL reconstructions, 5 traumatic lesions. The range of motion of the knee was between 5 and 120 degrees. Patients complained of a burning pain in the patellar region and the sensation that the knee was held in a vice. The average Insall index was 0.55 (0.3 to 0.87). 25 patients had osteoporosis of the patella and 31 patients had a typical "sunrise" aspect on axial radiographs in 30 degrees of flexion. The usual diagnosis was that of algodystrophy. All patients underwent patellar tendon lengthening.
Intra operative findings showed transverse retractions leading to resection of the medial and lateral retinaculum. The patellar tendon was short but its histological structure was normal. 15 patients had excellent results with no residual pain and were able to resume sports activities. 11 had good results with residual pain in hyperflexion and 9 had poor functional results, however nocturnal pain disappeared. Range of motion was between 0 and 130 degrees. Radiographic results were excellent since the preoperative average Insall score of 0.55 increased to 1.02 at follow-up.
Patella infera is caused by combination of two factors: patellar surgery (painful patellar syndrome, patellar instability, ACL reconstruction using the mid third of the patellar tendon) and painful post operative rehabilitation with no active quadriceps contractions. To avoid this complication, the knee should be braced in 20 degrees of flexion to tense the patellar tendon and rehabilitation should be undertaken with active quadriceps contractions. Patellar lengthening is a successful procedure with the results being dependent upon number of previous surgeries, cartilage damage and, most importantly, the patellar index: between 0.8 and 0.65 the results are uncertain, < 0.6, the results are usually good.
Patella infera is not a frequent complication of knee surgery. It is important to diagnose it early in order to prevent it. For chronic cases, surgical criteria should be strict: sensation of burning pain, lack of motion, unstable flexed monopodal stance, "sunrise" aspect on axial radiographs and a patellar index < 0.6. Patella infera differs from algodystrophy and re operation by retinacular release is indicated if the delay from previous surgery is < 2 months. In older cases, patellar tendon lengthening should be undertaken.
低位髌骨是一种术后并发症，多数情况下可以预防。本研究旨在确定其病因，并确定避免膝关节手术后出现低位髌骨的方法。作者描述了一种纠正该并发症的新手术技术，并阐述了取得良好效果的预后因素。
1985年至1991年，对35例患者实施了35次髌腱延长术。其中女性28例，男性7例，平均年龄37岁（21至72岁）。平均随访27个月，所有患者均有影像学随访。所有患者既往均有膝关节手术史：21例因髌前疼痛（=髌前疼痛），9例进行了前交叉韧带重建，5例为创伤性损伤。膝关节活动范围在5度至120度之间。患者主诉髌前区灼痛，感觉膝关节被夹住。平均Insall指数为0.55（0.3至0.87）。25例患者有髌骨骨质疏松，31例患者在30度屈曲位的轴位X线片上有典型的“日出”表现。通常诊断为痛性营养不良。所有患者均接受了髌腱延长术。
术中发现横向挛缩导致内外侧支持带切除。髌腱短，但组织结构正常。15例患者效果极佳，无残留疼痛，能够恢复体育活动。11例效果良好，在过度屈曲时有残留疼痛，9例功能效果较差，但夜间疼痛消失。活动范围在0度至130度之间。影像学结果极佳，因为术前平均Insall评分为0.55，随访时增至1.02。
低位髌骨由两个因素共同导致：髌骨手术（髌前疼痛综合征、髌骨不稳定、使用髌腱中三分之一进行前交叉韧带重建）以及术后痛苦的康复过程且股四头肌无主动收缩。为避免该并发症，膝关节应在20度屈曲位支具固定以拉紧髌腱，康复过程应进行股四头肌主动收缩训练。髌腱延长术是一种成功的手术，其结果取决于既往手术次数、软骨损伤情况，最重要的是髌骨指数：在0.8至0.65之间结果不确定，<0.6时结果通常良好。
低位髌骨并非膝关节手术常见的并发症。早期诊断以预防其发生很重要。对于慢性病例，手术标准应严格：有灼痛感觉、活动受限、屈曲单足站立不稳定、轴位X线片上有“日出”表现且髌骨指数<l0.6。低位髌骨与痛性营养不良不同，若距上次手术时间<2个月，建议行支持带松解再手术。对于病程较长的病例，应进行髌腱延长术。
