Excellent outcomes following repair of Grade I-II isolated posterolateral corner injury and meniscal instability using an all-inside, arthroscopic technique.

Purpose: Injuries of the posterolateral corner (PLC) of the knee can lead to chronic rotational instability, pain and functional impairment. Isolated PLC injuries are commonly combined with lateral meniscus instability and are often overlooked, causing persistent symptoms and instability in patients. The purpose of this study was to introduce an all-inside, arthroscopic technique for treating isolated, Grade I-II PLC injuries combined with lateral meniscus instability and report its clinical outcomes and failure rates. Methods: A total of 52 patients who had been diagnosed with isolated Grade I-II PLC injury with concomitant lateral meniscus instability, and were treated between 2014 and 2019 with the proposed technique, were included. Demographic, preoperative, intraoperative and postoperative data were collected and reviewed. Patient-reported outcomes included a visual analogue scale (VAS) assessing pain, the International Knee Documentation Committee Subjective Knee Function (IKDC-SKF) score, the Tegner Activity Scale and a patient-acceptable symptom state (PASS). At follow-up, all patients were clinically evaluated by an independent, fellowship-trained orthopaedic surgeon, using the grinding test, the dial test, the posterolateral drawer test, the varus stress test and the McMurray test. Failure was defined as a negative PASS response, the need for revision surgery or the persistence of rotational instability as demonstrated by clinical tests. Results: At a mean follow-up of 28.1 months, 98% of the patients declared satisfied with the procedure. Rotational instability, as assessed by the grinding test, dial test, posterolateral drawer test and varus stress test, showed significant improvement in 51 out of 52 patients ( Conclusion: All-inside, arthroscopic repair of subtle, isolated PLC injuries combined with lateral meniscus instability can result in favourable clinical outcomes, high patient satisfaction and excellent return-to-sport rates. High suspicion and meticulous clinical examination are required to successfully diagnose these injuries, which are often missed during the initial presentation. Level of Evidence: Level III.