Senior Department of Orthopedics, The Fourth Medical Center of PLA General Hospital, No. 51 Fucheng Road, Beijing, 100048, China.
National Clinical Research Center for Orthopedics, Sports Medical and Rehabilitation, Beijing, China.
J Orthop Surg Res. 2022 Sep 5;17(1):407. doi: 10.1186/s13018-022-03255-6.
Mobile-bearing unicompartmental knee arthroplasty (MB-UKA) is an effective treatment for anteromedial knee osteoarthritis. Meticulous intraoperative soft tissue balancing remains challenging yet consequential for a successful operation. Currently, surgeons rely mostly on their experience during soft tissue balancing, yielding unreproducible results. The purpose of this study was to quantified measure the soft tissue tension of medial compartment and determine if an optimal "target" tension values with the natural state exists.
This was an observational study of 24 consecutive patients. All 30 UKAs were performed by a single surgeon. The piezoresistive sensor was custom designed to fit in the medial compartment gap. Contact pressures were measured at 5 angular positions of the knee intraoperatively: 0°, 20°, 45°, 90°, and 110° of flexion. The change in pressure from extension (20° position) and flexion (110° position) was also calculated (E-FPD). Data on age, sex, body mass index, operative side, and bearing size were collected. Outcome measures were measured at baseline and at the 6-month postoperative follow-up; Oxford Knee Score, visual analog scale score, and range of motion were compared to evaluate clinical outcomes.
There was a significant improvement in patients in all measured outcomes at 6 months from baseline (P < 0.05). The E-FPD of 14.9 N (8.9, 24.6) was indicative of appropriate soft tissue balancing throughout the functional range of knee motion. Of 30 knees, 22 were 3-mm bearing and 8 were 4- or 5-mm bearing. The pressure data of the 3-mm bearing group was larger than that of the non-3-mm bearing group for each knee flexion degree, but the difference was not statistically significant (P > 0.05).
Objective data from sensor output may assist surgeons in decreasing loading variability during MB-UKA. The data suggested that MB-UKA could not accurately restore soft tissue tension to the natural state, which was related to the inability of MB-UKA surgical instruments to fine adjust the bone cut and soft tissue release.
Chinese Clinical Trial Registry ( http://www.chictr.org.cn ): ChiCTR1900024146.
活动平台单髁膝关节置换术（MB-UKA）是治疗前内侧膝关节骨关节炎的有效方法。精细的术中软组织平衡仍然具有挑战性，但对手术的成功至关重要。目前，外科医生主要依靠他们在软组织平衡过程中的经验，导致结果不可重复。本研究的目的是定量测量内侧间室的软组织张力，并确定是否存在一个与自然状态相匹配的“理想”张力值。
这是一项连续 24 例患者的观察性研究。所有 30 例 UKA 均由一位外科医生完成。压阻式传感器经过定制，以适应内侧间室间隙。术中在膝关节的 5 个角位置测量接触压力：0°、20°、45°、90°和 110°的屈曲。还计算了从伸展（20°位置）到屈曲（110°位置）的压力变化（E-FPD）。收集年龄、性别、体重指数、手术侧和轴承尺寸等数据。在基线和术后 6 个月随访时评估结果测量值；牛津膝关节评分、视觉模拟评分和运动范围用于评估临床结果。
与基线相比，所有测量结果在 6 个月时均有显著改善（P<0.05）。14.9N（8.9，24.6）的 E-FPD 表明在膝关节运动的整个功能范围内软组织平衡适当。30 个膝关节中，22 个为 3mm 轴承，8 个为 4 或 5mm 轴承。在每个膝关节屈曲度下，3mm 轴承组的压力数据均大于非 3mm 轴承组，但差异无统计学意义（P>0.05）。
传感器输出的客观数据可能有助于外科医生减少 MB-UKA 过程中的加载变异性。数据表明，MB-UKA 不能准确地将软组织张力恢复到自然状态，这与 MB-UKA 手术器械无法精细调整骨切割和软组织释放有关。
中国临床试验注册中心（http://www.chictr.org.cn）：ChiCTR1900024146。
