The hypermobile and unstable lateral meniscus: a narrative review of the anatomy, biomechanics, diagnosis and treatment options

Hypermobile lateral meniscus: A systematic review of current treatment options

PURPOSE

The reliable data on the incidence of hypermobile lateral meniscus (HLM) and its clinical manifestations, diagnostic methods and therapeutic approaches are limited. This systematic study aimed to review available treatment options for HLM and the outcomes of each approach.

METHODS

A systematic search was performed in four electronic databases (PubMed, EMBASE, Scopus, Web of Science) to identify studies in which arthroscopically confirmed cases of HLM were treated surgically or nonsurgically, and the required data comprising study characteristics, patient data, treatment approaches and outcome measures were extracted from eligible studies.

RESULTS

Twenty studies with a total of 212 patients (138 males and 74 females) and 219 knees were included. The most frequently reported symptoms were locking sensations, knee pain, giving way and snapping. Treatments used by the studies were: radiofrequency energy in two studies; arthroscopic partial meniscectomy in one study; open surgery in two studies; and arthroscopic meniscal repair in 17 studies. Eleven studies used an all-inside repair method and an inside-out meniscal repair was reported in eight studies. Three studies reported the usage of posterior arthroscopy for therapeutic or diagnostic approaches. Evaluation of symptom resolution was the main outcome measurement for which almost all of the studies stated relief of symptoms after intervention.

CONCLUSION

Despite the lack of definite consensus about the most appropriate intervention for HLM, therapeutic preference was directed towards arthroscopic all-inside and inside-out repair techniques. Although the surgeon's decision remains the key factor in choosing the most suitable treatment option for each individual, posterior arthroscopic meniscal repair may be considered as a better option for HLM treatment according to the findings of this review.

LEVEL OF EVIDENCE

Level IV.

Surgical Repair of Hypermobile Lateral Meniscus Secondary to Popliteomeniscal Fascicle Tears Improves Pain and Mechanical Symptoms

Purpose

To describe the clinical and radiographic features associated with isolated hypermobile lateral meniscus (HLM), and report patient outcomes following surgically repaired isolated HLM.

Methods

All patients diagnosed with HLM from 2000 to 2020 at a single academic institution were identified and reviewed. Patients were excluded if they had concomitant ligament injury or lacked 2-year follow-up. Preoperative and postoperative visual analog scale (VAS) pain scores were determined from clinical notes. Statistical analysis was performed in JMP, and statistical significance was determined with use of a paired t-test.

Results

Eighteen knees in 17 patients met inclusion criteria. Mean patient age was 24.1 (range: 6-61) years. Mean follow-up was 73 months (25-151 months). All 18 knees reported pain at presentation; 94% (17/18) had mechanical symptoms. All 18 knees had preoperative MRIs, but only 1 (5.6%) knee was correctly diagnosed by a musculoskeletal trained radiologist. Most repairs were performed with an all-inside technique (61%, 11/18). VAS score improved significantly from 7.2 ± 2.9 preoperatively to 0.7 ± 1.9 postoperatively, with average improvement of VAS score of 6.5 (P < .001). Only one (5.6%) knee required revision meniscal surgery.

Conclusion

Hypermobile lateral meniscus patients commonly see multiple providers, fail to have their HLM diagnosed on MRI, and undergo various treatments prior to a successful diagnosis. Localized lateral joint line pain, mechanical symptoms, and absence of distinct meniscus tear on MRI are the most frequent clinical presentations. Surgery with meniscus repair is a reliable solution to improve pain and mechanical symptoms.

Level of Evidence

Level IV, therapeutic case series.