Purpose

The purpose of this study was to compare the clinical results, radiographic loosening and early complications between patients undergoing primary knee arthroplasty (TKA) with tibial short stem extension and those with standard stem for gross varus deformities at minimum two years after surgery.

Methods

From a prospective TKA database of 4216 patients, patients with a primary TKA with a tibial short stem extension (30 mm) for severe varus deformity (hip-kneeankle angle, HKA < 170°) and a minimum follow-up of 2 years, were reviewed and compared to a matched control group with tibial components with a standard stem, in a

1:3 ratio. Demographics, surgical parameters, pre- and postoperative alignment and outcome parameters were collected for all patients. The primary outcome was aseptic loosening of the tibial component. Secondary outcomes were knee society scores (KSS), postoperative HKA, general postoperative complications and implant survival rates.

Results

Forty-five patients with tibial short stem extensions (mean HKA 166.2°) were compared in a 1:3 ratio to a matched case–control group of 135 patients with standard stems (mean HKA 167.1°) at a mean follow-up of 57 and 64 months respectively after primary TKA. In the extension stem group, 4 patients encountered complications

(8.9%) versus 12 patients in the standard stem group (8.9%). There were no cases of tibial component loosening in the short extension stem versus four cases in the standard stem group (3%). This difference was significant between groups, p = 0.04.

Conclusion

In patients with varus deformities > 10°, undergoing primary total knee arthroplasty, prophylactic use of a tibial short extension stem may lead to less loosening of the tibial component. In this study, 3% of patient with big varus deformity without stemmed TKA had a tibial implant loosening versus 0% in the stemmed TKA group.

Level of evidence

Level III, case–control study

中文翻译：

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伴有严重内翻畸形的胫骨短延伸茎的原发性TKA的生存期至少延长2年。

目的

这项研究的目的是比较在术后至少两年内接受胫骨短茎延长的原发性膝关节置换术（TKA）与标准茎的大内翻畸形患者的临床结果，放射线学松动和早期并发症。

方法

从前瞻性TKA数据库中的4216名患者中，对原发性TKA患者进行胫骨短茎延长（30 mm）的内翻严重畸形（髋关节后倾角，HKA <170°），且至少随访2年。审查并与具有标准茎的胫骨组件的匹配对照组进行比较

1：3的比例。收集了所有患者的人口统计学，外科手术参数，术前和术后对准以及结果参数。主要结局是无菌性胫骨组件松动。次要结果是膝关节社会评分（KSS），术后HKA，一般术后并发症和植入物存活率。

结果

将四十五名胫骨短茎延伸患者（平均HKA 166.2°）以1：3的比例与135例标准茎（平均HKA 167.1°）的配对病例对照组进行比较，平均随访时间为57原发性TKA后64个月和64个月。在延长杆组中，有4例患者出现并发症

（8.9％）与标准干组的12名患者（8.9％）相比。短伸茎中没有胫骨组件松动的情况，而标准茎组中有4例（3％）。两组之间的差异显着，p  = 0.04。

结论

在内翻畸形> 10°的患者中，进行初次全膝关节置换术时，预防性使用胫骨短延伸杆可能会减少胫骨组件的松弛。在这项研究中，无茎TKA的大内翻畸形患者中有3％的胫骨植入物松动，而茎干TKA组为0％。

证据水平

第三级，病例对照研究