Department of Orthopaedic Surgery, Walter Reed National Military Medical Center, Bethesda, MD.
Inova Mount Vernon Hospital Joint Replacement Center, Alexandria, VA; Anderson Orthopaedic Research Institute, Alexandria, VA.
J Arthroplasty. 2021 Dec;36(12):3883-3887. doi: 10.1016/j.arth.2021.08.015. Epub 2021 Aug 20.
To assess how implant alignment affects unicompartmental knee arthroplasty (UKA) outcome, we compared tibial component alignment of well-functioning UKAs against 2 groups of failed UKAs, revised for progression of lateral compartment arthritis ("Progression") and aseptic loosening ("Loosening").
We identified 37 revisions for Progression and 61 revisions for Loosening from our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000. Revision cohorts were matched on age, gender, body mass index, and postoperative range of motion with "Successful" unrevised UKAs with minimum 10-year follow-up and Knee Society Score ≥70. Tibial component coronal (TCA) and sagittal (TSA) plane alignment was measured on postoperative radiographs. Limb alignment was quantified by hip-knee-ankle (HKA) angle on long-leg radiographs. In addition to directly comparing groups, a multivariate logistic regression examined how limb and component alignments were associated with UKA revision.
In the Progression group, component alignment was similar to the matched successes (TCA 3.6° ± 3.5° varus vs 5.1° ± 3.5° varus, P = .07; TSA 8.4° ± 4.4° vs 8.8° ± 3.6°, P = .67), whereas HKA angle was significantly more valgus (0.3° ± 3.6° valgus vs 4.4° ± 2.6° varus, P < .001). Loosening group component alignment was also similar to the matched successes (TCA 6.1° ± 3.7° varus vs 5.9° ± 3.1° varus, P = .72; TSA 8.4° ± 4.6° vs 8.1° ± 3.9°, P = .68), and HKA was significantly more varus (6.1° ± 3.1° varus vs 4.0° ± 2.7° varus, P < .001). Using a multivariate logistic regression, HKA angle was the most significant factor associated with revision (P < .001).
In this population of revised UKAs and long-term successes, limb alignment was a more important determinant of outcome than tibial component alignment.
Level III case-control study.
为了评估植入物对线对线的影响，我们比较了功能良好的单髁膝关节置换术（UKA）与 2 组因外侧间室关节炎进展（“进展”）和无菌性松动（“松动”）而翻修的 UKA 的胫骨组件对线。
我们从 2000 年以来进行的 3351 例内侧固定平台 UKA 的前瞻性机构数据库中，确定了 37 例进展组和 61 例松动组的翻修。翻修组按年龄、性别、体重指数和术后活动范围与至少 10 年随访且膝关节学会评分≥70 的“成功”未翻修 UKA 进行匹配。术后 X 线片上测量胫骨组件冠状（TCA）和矢状（TSA）平面对线。下肢对线通过下肢全长 X 线片上的髋膝踝（HKA）角来量化。除了直接比较组外，多元逻辑回归还检查了下肢和组件对线与 UKA 翻修的关系。
在进展组中，与匹配的成功病例相比，组件对线相似（TCA 3.6°±3.5° 内翻与 5.1°±3.5° 内翻，P=0.07；TSA 8.4°±4.4°与 8.8°±3.6°，P=0.67），而 HKA 角明显更外翻（0.3°±3.6°外翻与 4.4°±2.6° 内翻，P<0.001）。松动组的组件对线与匹配的成功病例也相似（TCA 6.1°±3.7° 内翻与 5.9°±3.1° 内翻，P=0.72；TSA 8.4°±4.6°与 8.1°±3.9°，P=0.68），HKA 角明显更外翻（6.1°±3.1° 内翻与 4.0°±2.7° 外翻，P<0.001）。使用多元逻辑回归，HKA 角是与翻修最相关的因素（P<0.001）。
在这组翻修的 UKA 和长期成功病例中，下肢对线是比胫骨组件对线更重要的结果决定因素。
III 级病例对照研究。
