Nwankwo Tobenna N, Strait Alexander V, Ho Henry, Fricka Kevin B, Hamilton William G, Sershon Robert A
Anderson Orthopaedic Research Institute, Alexandria, Virginia.
Anderson Orthopaedic Research Institute, Alexandria, Virginia; Inova Mount Vernon Hospital Joint Replacement Center, Alexandria, Virginia.
J Arthroplasty. 2025 Jun 17. doi: 10.1016/j.arth.2025.06.041.
Unicondylar knee arthroplasty (UKA) conversion to total knee arthroplasty (TKA) is associated with greater resource utilization and morbidity than primary TKA. However, it is unclear how the indication for conversion to TKA impacts outcomes. This study evaluated if aseptic UKA failure mode affects subsequent TKA survivorship at a high-volume institution.
A prospectively maintained institutional database was queried for all conversion TKA, primary TKA, and first-time revision TKA performed by nine surgeons between 2000 and 2023. This resulted in 439 UKA conversions to TKA and comparator groups of 15,026 primary and 1,432 revision TKAs. Conversions were grouped by UKA failure mode, with a focus on the 413 aseptic failures. The primary outcome measure was aseptic conversion TKA survivorship using revision for any reason as an end point. Secondary outcomes included survivorship between all TKA procedures. The mean follow-up length for conversion TKAs was 5.7 (range, zero to 22.4) years.
There were no statistically significant differences in survivorship between conversion TKAs based on their aseptic UKA failure mode (P = 0.80). The most common reasons for conversion of UKA to TKA were progression of osteoarthritis (129 of 413), tibial component loosening and subsidence (112 of 413), polyethylene wear with osteolysis (93 of 413), femoral component loosening (38 of 413), and tibial fracture (17 of 413). There were 11 conversion TKAs that required subsequent revision. The overall survivorship of aseptic conversion TKA was similar to primary TKA (P = 0.72), with 10-year rates of 95.6% (95% CI [confidence interval], 91.7 to 97.7) and 95.8% (95% CI, 95.3 to 96.3), respectively. Both procedures demonstrated greater survivorship than aseptic revision TKAs (P < 0.001), which had a 10-year rate of 84.2% (95% CI, 80.5 to 87.3).
Our institutional experience demonstrated that UKA conversion to TKA can be successfully performed regardless of aseptic UKA failure mode. Survivorship of aseptic conversion TKA was similar to that of primary TKA for up to 10 years and significantly better than that of the first-time revision TKA.
与初次全膝关节置换术（TKA）相比，单髁膝关节置换术（UKA）转换为TKA会带来更多的资源利用和更高的发病率。然而，尚不清楚转换为TKA的指征如何影响手术结果。本研究评估了在一家大型机构中，无菌性UKA失败模式是否会影响后续TKA的生存率。
查询了一个前瞻性维护的机构数据库，以获取2000年至2023年间由9名外科医生进行的所有TKA转换手术、初次TKA手术和首次翻修TKA手术。这产生了439例UKA转换为TKA的病例，以及15026例初次TKA和1432例翻修TKA的对照组。转换病例按UKA失败模式分组，重点关注413例无菌性失败病例。主要结局指标是无菌性转换TKA的生存率，以任何原因的翻修为终点。次要结局包括所有TKA手术之间的生存率。转换TKA的平均随访时间为5.7年（范围为0至22.4年）。
基于无菌性UKA失败模式的转换TKA之间的生存率无统计学显著差异（P = 0.80）。UKA转换为TKA最常见的原因是骨关节炎进展（413例中的129例）、胫骨组件松动和下沉（413例中的112例）、聚乙烯磨损伴骨溶解（413例中的93例）、股骨组件松动（413例中的38例）和胫骨骨折（413例中的17例）。有11例转换TKA需要后续翻修。无菌性转换TKA的总体生存率与初次TKA相似（P = 0.72），10年生存率分别为95.6%（95%可信区间[CI]，91.7%至97.7%）和95.8%（95%CI，95.3%至96.3%）。两种手术的生存率均高于无菌性翻修TKA（P < 0.001），无菌性翻修TKA的10年生存率为84.2%（95%CI，80.5%至87.3%）。
我们机构的经验表明，无论无菌性UKA失败模式如何，UKA转换为TKA都可以成功进行。无菌性转换TKA的生存率在长达10年的时间里与初次TKA相似，且显著优于首次翻修TKA。
