Grand Rapids Medical Education Partners, 1000 Monroe Ave NW, Grand Rapids, MI 49503, USA.
Injury. 2012 Jul;43(7):1084-9. doi: 10.1016/j.injury.2012.01.025. Epub 2012 Feb 18.
The majority of periprosthetic fractures around the knee occur at the supracondylar region of the distal femur. Fixation of distal femoral fractures in osteoporotic bone with short segment remains a challenge, especially after total knee arthroplasty (TKA). Internal fixation of these fractures using locking plates has become popular. The purpose of this study was to evaluate a consecutive series of periprosthetic supracondylar femoral fractures treated with locked periarticular plate fixation with regard to surgical procedure, complications and clinical outcome.
From two academic trauma centres, 55 consecutive periprosthetic distal femoral fractures (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association, AO/OTA 33) were retrospectively identified as having been treated with locked plate fixation. Of these, 36 fractures in 35 patients (86.1% female) met the inclusion criteria. Patients had an average age of 73.2 years (range 54-95 years). Fixation constructs for plate length and working length were delineated. Nonunion, infection and implant failure were used as complication variables. Demographics were assessed. Outcome was addressed radiographically and clinically according to Kristensen et al.(1) by range of motion and pain.
Twenty-five of 36 fractures (69.4%) healed after the index procedure. Eight of 36 fractures (22.2%) developed a nonunion with three fractures (8.3%) leading to hardware failure. Nine of the 36 patients (25%) were radiographically diagnosed with notching of the anterior femoral cortex. Regarding technical aspects, distance from the anterior flange of the femoral component to fracture was significantly shorter in patients with compared to without anterior notching (t=3.68, p=0.02). Patients who underwent submuscular plate insertion compared to an extensive lateral approach had a reduced nonunion risk (χ(2)=0.05). No difference in infection rate was found for submuscular procedures compared with open procedures (χ(2)=0.85). Range of motion was reduced in most of the patients and 13.5% had a persistent loss of extension of 5°. More than 77% of the patients reported no or only mild pain during the last office visit. Range of motion loss did not influence pain. Successful treatment according to Cain et al.(2) was achieved in 83%. Using Kristensen's(1) criteria, 56% of the knees had acceptable flexion.
Operative fixation of periprosthetic distal femoral fractures after TKA continues to be challenging. Notching of the anterior femoral cortex should be avoided. Loss of reduction and high failure rates still occur with locked plating and may be related to underlying factors. Indirect reduction and submuscular plate insertion technique reduce nonunion risk.
膝关节周围的大多数假体周围骨折发生在股骨远端的髁上区域。在骨质疏松性骨骼中用短节段固定股骨远端骨折仍然是一个挑战，尤其是在全膝关节置换术（TKA）之后。使用锁定钢板固定这些骨折已经变得很流行。本研究的目的是评估使用关节周围锁定钢板固定治疗的连续系列假体周围髁上股骨骨折的手术过程、并发症和临床结果。
从两个学术创伤中心，回顾性确定了 55 例连续的假体周围股骨远端骨折（AO/OTA 33 型），这些骨折被认为是用锁定钢板固定治疗的。其中，35 名患者中的 36 例骨折（86.1%为女性）符合纳入标准。患者的平均年龄为 73.2 岁（范围 54-95 岁）。确定了钢板长度和工作长度的固定结构。将非愈合、感染和植入物失败作为并发症变量。评估了人口统计学数据。根据 Kristensen 等人的标准，通过活动范围和疼痛评估影像学和临床结果。（1）
36 例骨折中有 25 例（69.4%）在初次手术后愈合。36 例骨折中有 8 例（22.2%）发生了不愈合，其中 3 例（8.3%）导致了内固定物失败。36 例患者中有 9 例（25%）被放射学诊断为股骨前皮质切迹。关于技术方面，与没有前切迹的患者相比，股骨组件前凸缘到骨折的距离明显更短（t=3.68，p=0.02）。与广泛的外侧入路相比，肌下钢板插入的患者发生非愈合的风险降低（χ(2)=0.05）。与开放式手术相比，肌下手术的感染率没有差异（χ(2)=0.85）。大多数患者的活动范围受限，13.5%的患者有 5°的持续伸膝丧失。在最后一次就诊时，超过 77%的患者报告没有或只有轻度疼痛。活动范围的丧失并不影响疼痛。根据 Cain 等人的标准，83%的患者获得了成功的治疗。（2）根据 Kristensen 的标准，（1）56%的膝关节有可接受的屈曲度。
TKA 后假体周围股骨远端骨折的手术固定仍然具有挑战性。应避免股骨前皮质切迹。用锁定钢板固定仍会发生复位丢失和高失败率，这可能与潜在因素有关。间接复位和肌下钢板插入技术可降低非愈合风险。
