Martin Benjamin D, Cherkashin Alexander M, Tulchin Kirsten, Samchukov Mikhail, Birch John G
Children's National Medical Center, Washington, DC, USA.
J Pediatr Orthop. 2013 Jun;33(4):446-52. doi: 10.1097/BPO.0b013e3182784e5d.
Knee stiffness is common after femoral lengthening. Certain patients require a quadricepsplasty when therapy does not improve flexion. A small subset of such patients may also have obligate patellar dislocation with knee flexion due to contracture of the extensor mechanism. We describe our surgical approach for both clinical situations and our outcomes in a pediatric population.
Six patients, 2 with obligate patellar dislocation, were reviewed (9% of our femoral lengthening population). Indications for surgery included persistent symptomatic restriction of flexion after at least 3 months of therapy or obligate lateral patellar dislocation with knee flexion. Knee range of motion and clinical strength were assessed. Four patients were available for gait analysis and concentric quadriceps strength testing by isokinetic dynamometer. Patient satisfaction was surveyed by questionnaire.
All patients had full flexion before lengthening. The mean length gained (by circular external fixation and/or intramedullary motorized nail) was 10.7 cm. The mean age at the time of quadricepsplasty was 16 years. The average active flexion preoperatively was only 48 degrees. Two patients with obligate patellar dislocation and relatively good knee flexion inflated the average preoperative knee flexion. Although both had knee flexion to 100 degrees, the patella dislocated with flexion beyond 30 degrees. At follow-up (mean, 6.2 y) active flexion averaged 120 degrees (P<0.004). All patients had 5/5 clinical strength and no significant quadriceps lag. No patients had patellar instability postoperatively. Isokinetic dynamometer revealed an average weakness of 63% compared with the nonoperative quadriceps. Gait analysis indicated patients had near-normal gait patterns. All patients were satisfied and would pursue the same treatment.
Our quadricepsplasty can significantly increase knee flexion and treat obligate patellar dislocation in the setting of extension contracture after femoral lengthening when nonoperative measures fail.
Level IV.
股骨延长术后膝关节僵硬很常见。当治疗无法改善膝关节屈曲时，某些患者需要进行股四头肌成形术。这类患者中的一小部分可能还会因伸肌机制挛缩而在膝关节屈曲时出现髌骨习惯性脱位。我们描述了针对这两种临床情况的手术方法以及我们在儿科患者群体中的治疗结果。
对6例患者进行了回顾性研究，其中2例有髌骨习惯性脱位（占我们股骨延长患者群体的9%）。手术指征包括至少3个月的治疗后仍存在有症状的持续性屈曲受限，或膝关节屈曲时出现髌骨习惯性外侧脱位。评估了膝关节活动范围和临床肌力。4例患者可进行步态分析和通过等速测力计进行同心性股四头肌力量测试。通过问卷调查患者满意度。
所有患者在延长术前均能完全屈曲。平均延长长度（通过环形外固定和/或髓内动力钉）为10.7厘米。股四头肌成形术时的平均年龄为16岁。术前平均主动屈曲仅为48度。2例有髌骨习惯性脱位且膝关节屈曲相对较好的患者拉高了术前膝关节屈曲的平均值。尽管两人膝关节均能屈曲至100度，但髌骨在屈曲超过30度时脱位。随访时（平均6.2年），主动屈曲平均为120度（P<0.004）。所有患者临床肌力均为5/5，且无明显股四头肌滞后。术后无患者出现髌骨不稳定。等速测力计显示与未手术的股四头肌相比，平均肌力减弱63%。步态分析表明患者步态模式接近正常。所有患者均满意，且会选择相同的治疗方法。
当非手术措施无效时，我们的股四头肌成形术可显著增加股骨延长术后伸肌挛缩情况下的膝关节屈曲度，并治疗髌骨习惯性脱位。
IV级。
