Purpose

To investigate changes in meniscal extrusion during knee flexion before and after pullout fixation for medial meniscus posterior root tear (MMPRT) and determine whether these changes correlate with articular cartilage degeneration and short-term clinical outcomes.

Methods

Twenty-two patients (mean age 58.4 ± 8.2 years) diagnosed with type II MMPRT underwent open magnetic resonance imaging preoperatively, 3 months after transtibial fixation and at 12 months after surgery, when second-look arthroscopy was also performed. The medial meniscus medial extrusion (MMME) and the medial meniscus posterior extrusion (MMPE) were measured at knee 10° and 90° flexion at which medial meniscus (MM) posterior translation was also calculated. Articular cartilage degeneration was assessed using International Cartilage Research Society grade at primary surgery and second-look arthroscopy. Clinical evaluations included Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee subjective knee evaluation form, Lysholm score, Tegner activity level scale, and pain visual analogue scale.

Results

MMPE at 10° knee flexion was higher 12 months postoperatively than preoperatively (4.8 ± 1.5 vs. 3.5 ± 1.2, p = 0.01). MMPE at 90° knee flexion and MM posterior translation were smaller 12 months postoperatively than preoperatively (3.5 ± 1.1 vs. 4.6 ± 1.3, 7.2 ± 1.7 vs. 8.9 ± 2.0, p < 0.01). Articular cartilage degeneration of medial femoral condyle correlated with MMME in knee extension (r = 0.5, p = 0.04). All clinical scores significantly improved 12 months postoperatively. However, correlations of all clinical scores against decreased MMPE and increased MMME were not detected.

Conclusions

MMPRT transtibial fixation suppressed the progression of MMPE and cartilage degeneration and progressed MMME minimally in knee flexion position at 1 year. However, in the knee extension position, MMME progressed and correlated with cartilage degeneration of medial femoral condyle. MMPRT transtibial fixation contributes to the dynamic stability of the MM in the knee flexion position.

Level of evidence

IV.

中文翻译：

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胫骨内侧半月板后根撕裂的胫骨固定术可减少中老年患者的内侧半月板的后部挤压和生理平移。

目的

调查在内侧半月板后根撕裂术（MMPRT）拔除固定前后膝盖屈伸过程中半月板挤压的变化，并确定这些变化是否与关节软骨退变和短期临床结果相关。

方法

22例诊断为II型MMPRT的患者（平均年龄58.4±8.2岁）在术前，经胫骨固定后3个月和手术后12个月接受了开放式磁共振成像，同时还进行了第二眼关节镜检查。在膝盖弯曲10°和90°时测量内侧半月板内侧挤压（MMME）和内侧半月板后挤压（MMPE），同时计算内侧半月板（MM）的后移。关节软骨退行性变是在国际一级软骨手术和第二眼关节镜检查下使用国际软骨研究协会等级评估的。临床评估包括膝关节损伤和骨关节炎结果评分，国际膝关节文献委员会主观膝关节评估表，Lysholm评分，Tegner活动水平量表和疼痛视觉模拟量表。

结果

膝关节弯曲10°时的MMPE术后12个月高于术前（4.8±1.5 vs. 3.5±1.2，p  = 0.01）。术后12个月MMPE在90°屈膝和MM后移时比术前小（3.5±1.1 vs. 4.6±1.3，7.2±1.7 vs. 8.9±2.0，p  <0.01）。股骨内侧con的关节软骨退变与MMME在膝关节伸展中相关（r  = 0.5，p  = 0.04）。术后12个月所有临床评分均明显改善。但是，未检测到所有临床评分与MMPE降低和MMME升高之间的相关性。

结论

MMPRT胫骨固定抑制了MMPE的进展和软骨变性，并且在1年时屈膝位置的MMME进展最小。然而，在膝关节伸展位置，MMME进展并与内侧股骨con的软骨退变相关。MMPRT胫骨固定有助于MM屈膝时的动态稳定性。

证据水平

IV。