Department of Orthopaedic Surgery and Computer Assisted Surgery Center, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 East 70th Street, New York, NY, 10021, USA.
Department of Orthopaedic Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität, Berlin, Germany.
Knee Surg Sports Traumatol Arthrosc. 2023 Sep;31(9):3981-3991. doi: 10.1007/s00167-023-07441-9. Epub 2023 May 5.
A pre-arthritic alignment strategy for medial unicompartmental knee arthroplasty (UKA) aims to restore a patient's native lower limb alignment which may translate into improved outcomes. This study aimed to assess whether patients with pre-arthritically aligned knees versus patients with non-pre-arthritically aligned knees demonstrated improved mid-term outcomes and survivorship following medial UKA. The hypothesis was that pre-arthritic alignment in medial UKA would lead to better postoperative outcomes.
A retrospective study of 537 robotic-assisted fixed-bearing medial UKA was conducted. During this procedure, the surgical goal was to restore pre-arthritic alignment guided by re-tensioning of the medial collateral ligament (MCL). For study purposes, coronal alignment was retrospectively evaluated using the mechanical hip-knee-ankle angle (mHKA). Pre-arthritic alignment was estimated through the arithmetic hip-knee-ankle (aHKA) algorithm. Knees were grouped according to the difference between postoperative mHKA and estimated pre-arthritic alignment (i.e., mHKA - aHKA) as Group 1 (pre-arthritically aligned: mHKA restored within 2.0° of the aHKA), Group 2 (mHKA > 2.0° overcorrected relative to the aHKA), or Group 3 (mHKA > 2.0° undercorrected relative to the aHKA). Outcomes included the Knee Injury and Osteoarthritic Outcome Score for Joint Replacement (KOOS, JR), Kujala, proportions of knees achieving the patient acceptable symptom state (PASS) for these scores, and survivorship. PASS thresholds for KOOS, JR and Kujala were determined using a receiver operating characteristic curve method.
A total of 369 knees were categorized as Group 1, 107 as Group 2, and 61 as Group 3. At 4.4 ± 1.6 years follow-up, mean KOOS, JR was comparable among groups, while Kujala was significantly worse in Group 3. The proportion of knees achieving the PASS for Kujala (76.5 points) was lower in Group 3 (n = 32; 59%) compared to Group 1 (n = 260; 74%) (p = 0.02). 5-year survivorship was higher in Group 1 and Group 2 (99% and 100%, respectively) compared to Group 3 (91%) (p = 0.04).
Pre-arthritically aligned knees and knees with relative overcorrection from their pre-arthritic alignment following medial UKA demonstrated improved mid-term outcomes and survivorship compared to knees with relative under correction from their pre-arthritic alignment. These results encourage restoring or relatively overcorrecting pre-arthritic alignment to optimize outcomes following medial UKA, and caution against under correction from the pre-arthritic alignment.
IV, case series.
对于内侧单间室膝关节置换术（UKA），术前关节炎对线策略旨在恢复患者的原生下肢对线，这可能会转化为更好的结果。本研究旨在评估内侧 UKA 中术前关节炎对线的患者与术前非关节炎对线的患者相比，在中期随访时是否具有更好的结果和生存率。假设是内侧 UKA 中的术前关节炎对线会导致更好的术后结果。
对 537 例机器人辅助固定轴承内侧 UKA 进行回顾性研究。在此过程中，手术的目标是通过内侧副韧带（MCL）的重新拉紧来恢复术前关节炎对线。为了研究目的，通过机械髋膝踝角（mHKA）回顾性评估冠状对线。术前关节炎对线通过算术髋膝踝（aHKA）算法进行估计。根据术后 mHKA 与估计的术前关节炎对线之间的差异（即 mHKA-aHKA）将膝关节分为三组：第 1 组（术前关节炎对线：mHKA 在 aHKA 的 2.0°以内恢复），第 2 组（mHKA 过度纠正相对于 aHKA 超过 2.0°），或第 3 组（mHKA 相对于 aHKA 纠正不足超过 2.0°）。结果包括膝关节损伤和骨关节炎结果评分（KOOS，JR）、Kujala、达到这些评分患者可接受症状状态（PASS）的膝关节比例以及生存率。使用接收者操作特征曲线方法确定 KOOS、JR 和 Kujala 的 PASS 阈值。
共有 369 个膝关节被归类为第 1 组，107 个膝关节为第 2 组，61 个膝关节为第 3 组。在 4.4±1.6 年的随访中，各组之间的平均 KOOS、JR 相似，而 Kujala 在第 3 组中明显更差。第 3 组（n=32；59%）达到 Kujala 评分 PASS（76.5 分）的膝关节比例明显低于第 1 组（n=260；74%）（p=0.02）。第 1 组和第 2 组的 5 年生存率（分别为 99%和 100%）明显高于第 3 组（91%）（p=0.04）。
与内侧 UKA 后相对于术前关节炎对线的相对纠正不足的膝关节相比，内侧 UKA 后术前关节炎对线或相对过度纠正的膝关节具有更好的中期结果和生存率。这些结果鼓励恢复或相对过度纠正术前关节炎对线以优化内侧 UKA 后的结果，并告诫避免相对于术前关节炎对线的纠正不足。
IV，病例系列。
