膝外翻全膝关节置换外侧髌旁入路的手术方法探讨

目的探讨外侧入路行膝外翻全膝关节置换手术技术。方法采用膝关节外侧入路对中重度固定膝外翻患者行膝关节置换术。术中行膝关节正中偏外侧皮肤切口,行髂胫束苹果派样延长,自髌骨外侧“Z”字成形切开关节囊。以松解髂胫束止点、股骨侧及胫骨侧外侧副韧带及后外侧关节囊为主进行软组织平衡。股骨远端内外翻截骨定为5。外翻,股骨远端旋转角度截骨采用Whiteside线结合内外上髁轴线定位,全部病例均行髌骨置换。屈曲位缝合关节囊,将关节囊外侧袖套结构（深层）与内侧支持带边缘（浅层）缝合。结果8例10个膝外翻骨性关节炎患者采用外侧入路行全膝关节置换术。其中男1例1膝,女7例9膝。平均年龄68．2岁（58～79岁）。KrackowⅠ型外翻7例9膝,Ⅱ型1例1膝。临床分型均大于15°,属重度外翻。其中双膝关节同时置换2例4膝,单膝关节置换6例6膝。7例9膝采国产后稳定骨水泥型假体（TC—Dynamic,PLUS）,1例1膝采用进口旋转铰链式假体（RT—PLUS^TM Solution,PLUS）。全部患者术后外翻畸形均得到完全矫正,出院时均能独立或习步架辅助行走距离平均超过100m。关节活动度由术前平均95．6°（85°～110°）提高到术后平均117．1°（100°-125°）。被动内外翻活动度由术前平均12．6°（9°-15°）提高到术后0°。平均FTA角由术前的27．6°（20°～40°）提高到术后的6．8°（5°～9°）。KSS评分及功能评分由术前22．7分（9～48分）及26．5分（12—55分）分别提高到术后的86．4分（85～95分）及89．1分（80～95分）。术后平均随访时间19．6个月（1个月-51个月）,随访期间股胫角无明显变化,关节稳定性良好。结论采用外侧入路,关节囊“Z”字成形切开方法能够直接松解外侧韧带及软组织结构,并有效地缓解了腓总神经压力,解决了外侧软组织覆盖问题。

Total knee arthroplasty by lateral parapatellar approach for valgus knee

OBJECTIVE: To investigate the effect of lateral parapatellar approach in total knee arthroplasty (TKA) of valgus knee. METHODS: Lateral parapatellar approach of total knee arthroplasty was applied in 8 patients (10 knees) with severe valgus osteoarthritis knee (bilateral in 2 cases and unilateral in 6 cases), with the valgus angle > 15 degrees , 1 male (1 knee) and 7 females (9 knee), aged 68.2 (58 - 79), 7 cases (9 knees) being of the Krackow type I and 1 case (1 knee) of the Krackow type I, I. After incision of the skin through lateral knee, ilio-tibial band was prolonged by apple pie arthroplasty. The joint capsule was cut open laterally 2 - 4 cm from the para-patellar edge. Soft tissue balance was performed by releasing I - T band in Gerdy tubercle, lateral collateral ligament and poster-lateral capsule from the femur and tibial side. Valgus angle of distal femur cutting were five degree. Whiteside line and trans-epicondylar line were used as AP rotational cutting reference. All patellars of the group were resurfaced. Capsule closure is completed with the knee flexed. The expanded deep lateral soft tissue sleeve (coronal Z-plasty) is sutured with the medial retinaculum sleeve (superficial layer). Follow-up was conducted for 19.6 months (1 - 51 months). RESULTS: Seven cases (9 knees) were replaced by posterior stabilized cemented prostheses (TC-Dynamic, PLUS), one case (1 knee) was replaced by RT prosthesis (RT-PLUS(TM) Solution, PLUS). After operation, the valgus deformity of all patients was corrected and all patients could walk 100 m with or without the help of walking holders. The average range of motion (ROM) was improved from the pre-operative. 95.6 degrees (85 degrees - 110 degrees ) to the post-operative 117.1 degrees (100 degrees - 125 degrees ). The average femorotibial angle (FTA) was corrected from the pre-operative. 27.6 degrees (20 degrees - 40 degrees ) to the post-operative 6.8 degrees (5 degrees - 9 degrees ). The Knee Score System (KSS) score and functional score were improved from the pre-operative 22.7 points (9 - 48 points) and 26.5 points (12 - 55 points) to the post-operative 86.4 points (85 - 95 points) and 89.1 points (80 - 95 points) respectively. Follow-up showed that the FTA remained unchanged and the knee stability of all patients was good. CONCLUSION: Through lateral approach, "Z" plasty of the capsule can release the lateral structure and decrease the pressure of common peroneal nerve. For TKR with moderate to severe fixed valgus knee, lateral approach is an effective way to correct the deformity.