Endogap Joint Replacement Institute, Auenstraße 7, 82467, Garmisch-Partenkirchen, Germany.
Department Trauma Surgery, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418, Murnau, Germany.
Arch Orthop Trauma Surg. 2024 Mar;144(3):1353-1359. doi: 10.1007/s00402-023-05142-z. Epub 2024 Jan 12.
Tibial periprosthetic fractures (TPF) after unicompartmental knee arthroplasty (UKA) are a rare condition that affects about 1% of cases. Known risk factors include age, sex, body mass index (BMI), and bone density, as well as surgical technique and prosthesis design. The purpose of the study was to determine if undersizing of the tibial component in relation to the femoral component increases the risk of tibial periprosthetic fractures.
Over a 6-year-period 1542 patients with cemented (n = 363) and uncemented (n = 1179) medial UKA were retrospectively evaluated. Tibial periprosthetic fractures were identified and classified, and epidemiologic data were documented at follow-up. Undersizing was defined as a smaller tibial component compared to the femoral implant. The association of potential risk factors for TPF with the incidence of TPF was investigated with binominal logistic regression.
Fourteen patients (0.9%) suffered from TPF at a median of 1 month after surgery. The mean follow-up period was 5.9 ± 1.7 years. Fractures were more common in cases with undersized tibial components [odds ratio (OR) 3.2, p < 0.05]. Furthermore, older age (OR 1.1, p < 0.05) and female sex (OR 6.5, p < 0.05) were identified as significant risk factors, while BMI (p = 0.8) and cemented implantation (p = 0.2) had no effect on fracture rate. Revision surgery included open reduction and internal fixation or conversion to total knee arthroplasty.
Undersizing of implant sizes in UKA increases the risk for TPF especially in patients with small tibial implants. Therefore, mismatched implants should be avoided for UKA particularly when risk factors like obesity, older age, or female gender are present. Tibial periprosthetic fractures were successfully treated by open reduction and internal fixation or conversion to total knee arthroplasty.
单髁膝关节置换术后胫骨假体周围骨折（TPF）是一种罕见的情况，约占病例的 1%。已知的危险因素包括年龄、性别、体重指数（BMI）和骨密度，以及手术技术和假体设计。本研究的目的是确定胫骨假体相对于股骨假体的尺寸过小是否会增加胫骨假体周围骨折的风险。
回顾性分析了 6 年内接受骨水泥固定（n=363）和非骨水泥固定（n=1179）内侧 UKA 的 1542 例患者。在随访时发现并分类了胫骨假体周围骨折，并记录了流行病学数据。胫骨假体尺寸过小定义为胫骨组件相对于股骨植入物较小。使用二项逻辑回归分析潜在危险因素与 TPF 发生率的关系。
14 例患者（0.9%）在术后 1 个月中位数时发生 TPF。平均随访时间为 5.9±1.7 年。胫骨假体尺寸过小的病例中骨折更为常见[比值比（OR）3.2，p<0.05]。此外，年龄较大（OR 1.1，p<0.05）和女性（OR 6.5，p<0.05）被确定为显著危险因素，而 BMI（p=0.8）和骨水泥固定（p=0.2）对骨折率没有影响。翻修手术包括切开复位内固定或转换为全膝关节置换术。
UKA 中假体尺寸过小会增加 TPF 的风险，特别是在胫骨假体较小的患者中。因此，特别是在肥胖、年龄较大或女性等危险因素存在的情况下，应避免使用不匹配的假体进行 UKA。胫骨假体周围骨折通过切开复位内固定或转换为全膝关节置换术成功治疗。
