Hintermann Beat, Barg Alexej, Knupp Markus, Valderrabano Victor
Clinic of Orthopaedic Surgery, Kantonsspital, Rheinstrasse 26, CH-4410 Liestal, Switzerland.
J Bone Joint Surg Am. 2009 Apr;91(4):850-8. doi: 10.2106/JBJS.H.00229.
Pain following an ankle arthrodesis continues to be a challenging clinical problem. Recent reports on semiconstrained two-component ankle implants have demonstrated the feasibility of reversing a problematic ankle fusion and converting it to a total ankle arthroplasty. However, the failure rate is high. The objective of the present prospective study was to evaluate the intermediate-term outcome associated with the use of an unconstrained three-component ankle implant after taking down an ankle arthrodesis.
Thirty painful ankles in twenty-eight patients (average age, 58.2 years) who were managed with takedown of a fusion and total ankle arthroplasty were followed for a minimum of thirty-six months (average, 55.6 months). The outcome was assessed on the basis of clinical and radiographic evaluations.
In twenty-nine ankles in twenty-seven patients, the American Orthopaedic Foot and Ankle Society hindfoot score increased from 34.1 preoperatively to 70.6 at the time of the latest follow-up. Twenty-four patients (82.7%) were satisfied with the results. While five ankles were completely pain-free, twenty-one ankles were moderately painful, and three remained painful. The average clinically measured range of motion of 24.3 degrees amounted to 55.1% of that of the contralateral, unaffected ankle. Radiographically, the tibial component was stable in all ankles but one. The talar component was found to have migrated in four ankles but was asymptomatic in two of them. One ankle had to be revised to a tibiocalcaneal arthrodesis because of persistent pain and loosening of the talar component.
For patients with pain at the site of a failed ankle arthrodesis, conversion to total ankle arthroplasty with the use of a three-component ankle implant is a viable treatment option that provides reliable intermediate-term results. Key factors for the success of this procedure may be the intrinsic coronal plane stability provided by the ankle implants and the use of wider talar implants.
踝关节融合术后疼痛仍是一个具有挑战性的临床问题。近期关于半限制性双组件踝关节植入物的报告表明，逆转有问题的踝关节融合并将其转换为全踝关节置换术是可行的。然而，失败率很高。本前瞻性研究的目的是评估拆除踝关节融合术后使用非限制性三组件踝关节植入物的中期结果。
对28例患者（平均年龄58.2岁）的30个疼痛踝关节进行了融合拆除和全踝关节置换术，并至少随访36个月（平均55.6个月）。根据临床和影像学评估结果。
27例患者的29个踝关节中，美国矫形足踝协会后足评分从术前的34.1分提高到最近一次随访时的70.6分。24例患者（82.7%）对结果满意。5个踝关节完全无痛，21个踝关节中度疼痛，3个仍有疼痛。临床测量的平均活动范围为24.3度，相当于对侧未受影响踝关节的55.1%。影像学检查显示，除1个踝关节外，所有踝关节的胫骨组件均稳定。发现距骨组件在4个踝关节中发生了移位，但其中2个无症状。1个踝关节因持续疼痛和距骨组件松动而不得不翻修为胫跟关节融合术。
对于踝关节融合失败部位疼痛的患者，使用三组件踝关节植入物转换为全踝关节置换术是一种可行的治疗选择，可提供可靠的中期结果。该手术成功的关键因素可能是踝关节植入物提供的内在冠状面稳定性以及使用更宽的距骨植入物。
