Dennis Elizabeth R, Ammerman Brittany M, Nguyen Joseph T, Marmor William A, Pahapill Natalie K, Propp Bennett E, Gruber Simone, Brady Jacqueline M, Shubin Stein Beth E
Department of Orthopedics, Icahn School of Medicine at Mount Sinai Hospital, New York, New York, USA.
Department of Orthopedic Surgery, Hospital for Special Surgery, New York, New York, USA.
Am J Sports Med. 2025 Jul;53(8):1931-1939. doi: 10.1177/03635465251339822. Epub 2025 Jun 6.
Patients with recurrent instability underwent isolated medial patellofemoral ligament (MPFL) reconstruction regardless of anatomic risk factors within the confines of strict exclusion criteria. Previous publications from this cohort have been limited in the ability to identify risk factors for failure of isolated MPFL reconstruction when recurrent instability was defined as the only mode of failure, likely because of the small patient numbers who experienced this outcome.
To investigate whether persistence of postoperative apprehension and J-sign indicate suboptimal outcomes after isolated MPFL reconstruction and to determine if they may help identify patients who need bony realignment in addition to a soft tissue stabilization.
Case series; Level of evidence, 4Methods:Patients with recurrent patellar instability were prospectively enrolled from March 2014 to December 2019 and underwent primary, unilateral MPFL reconstruction by the senior author within the confines of strict exclusion criteria. Imaging measurements were obtained at baseline. Patient-reported outcome measures (PROMs) were collected at baseline and annually. Recurrent instability events (patellar dislocations or subluxations), return-to-sport (RTS) rates, presence of postoperative apprehension, and J-sign were collected at 1- and 2-year follow-ups.
A total of 138 knees (72% female; mean age, 20.1 ± 6.1 years) underwent isolated MPFL reconstruction between March 2014 and December 2019. The mean Beighton score was 5.3 ± 3.0, and knee hyperextension beyond 0° was 5.4° ± 2.8°. Of the knees evaluated, 95 (81%) had a preoperative J-sign and 89 (65%) had preoperative knee hyperextension. At 2 years, recurrent instability was reported in 6 knees (5%), postoperative apprehension in 9 knees (8%), and a postoperative J-sign in 44 knees (37%). No patients with postoperative apprehension reported recurrent instability. At 2 years, 89% of patients were able to RTS. Patients with both preoperative knee hyperextension and postoperative apprehension had worse RTS rates compared with patients without either ( = .034). Patients with postoperative J-signs had a significantly worse International Knee Documentation Committee score ( = .022), Knee injury and Osteoarthritis Outcome Score Physical Function Short Form score ( = .011), and Kujala score ( = .035) at the 2-year follow-up. For patients with recurrent instability or postoperative apprehension, the Kujala score was statistically significantly lower at 1 year compared with those without (84.9 vs 91.7; = .019).
In this prospective study of knees undergoing isolated MPFL reconstruction for recurrent patellofemoral instability, patients with postoperative J-signs showed worse PROMs at 2 years, a higher percentage of patients with preoperative knee hyperextension and postoperative apprehension did not RTS, and patients with postoperative apprehension did not experience recurrent instability. These findings support the need to further investigate if postoperative J-sign and apprehension may be important markers of suboptimal outcomes after isolated MPFL reconstruction for recurrent instability, which in turn may help identify patients who may benefit from concomitant bony realignment procedures at the time of their index procedure.
复发性髌骨不稳定患者在严格的排除标准范围内，无论解剖学风险因素如何，均接受单纯内侧髌股韧带（MPFL）重建术。该队列先前的出版物在确定单纯MPFL重建失败的风险因素方面能力有限，当时复发性不稳定被定义为唯一的失败模式，这可能是因为经历这种结果的患者数量较少。
探讨术后恐惧和J征的持续存在是否表明单纯MPFL重建术后效果欠佳，并确定它们是否有助于识别除软组织稳定外还需要进行骨结构调整的患者。
病例系列；证据等级，4
2014年3月至2019年12月前瞻性纳入复发性髌骨不稳定患者，由资深作者在严格的排除标准范围内进行初次单侧MPFL重建术。在基线时进行影像学测量。在基线时和每年收集患者报告的结局指标（PROMs）。在1年和2年随访时收集复发性不稳定事件（髌骨脱位或半脱位）、恢复运动（RTS）率、术后恐惧的存在情况和J征。
2014年3月至2019年12月期间，共有138例膝关节（72%为女性；平均年龄20.1±6.1岁）接受了单纯MPFL重建术。平均Beighton评分为5.3±3.0，膝关节过伸超过0°为5.4°±2.8°。在评估的膝关节中，95例（81%）术前有J征，89例（65%）术前有膝关节过伸。在2年时，报告有6例膝关节（5%）出现复发性不稳定，9例膝关节（8%）有术后恐惧，44例膝关节（37%）有术后J征。没有术后恐惧的患者报告复发性不稳定。在2年时，89%的患者能够恢复运动。术前膝关节过伸且术后有恐惧的患者与两者均无的患者相比，RTS率更差（P = 0.034）。术后有J征的患者在2年随访时国际膝关节文献委员会评分（P = 0.022）、膝关节损伤和骨关节炎结局评分身体功能简表评分（P = 0.011）和Kujala评分（P = 0.035）明显更差。对于有复发性不稳定或术后恐惧的患者，与没有这些情况的患者相比，1年时Kujala评分在统计学上明显更低（84.9对91.7；P = 0.019）。
在这项针对复发性髌股不稳定接受单纯MPFL重建术的膝关节的前瞻性研究中，术后有J征的患者在2年时PROMs更差，术前膝关节过伸且术后有恐惧的患者恢复运动的比例更高，术后有恐惧的患者未出现复发性不稳定。这些发现支持进一步研究术后J征和恐惧是否可能是复发性不稳定单纯MPFL重建术后效果欠佳的重要标志物，这反过来可能有助于识别在初次手术时可能从联合骨结构调整手术中获益的患者。
