The hypermobile lateral meniscus: a retrospective review of presentation, imaging, treatment, and results.

PURPOSE: Hypermobility of the posterior portion of the lateral meniscus has been reported in several recent case reports and small case series. Pathophysiology and optimal treatment have not been fully elucidated. Our purpose was to evaluate results following arthroscopic stabilization.

METHODS

Over a 10-year period, 13 knees were diagnosed at the time of arthroscopy as having hypermobility of the posterior portion of the lateral meniscus in the absence of a discrete tear or discoid morphology. Clinical presentation, pre-operative MRI findings, arthroscopic findings, and repair technique were retrospectively reviewed. Most recent outcomes data were gathered via a telephone interview utilizing the IKDC-9 questionnaire.

RESULTS

Eleven of 12 patients presented primarily with mechanical symptoms. Duration of symptoms ranged from 7 months to over 10 years. Eight of 12 patients did not recall any history of trauma. Twelve of 13 pre-operative MRIs did not identify a meniscal tear. Stabilization was obtained by fixation of the meniscus to the posterior capsule by various techniques. Average follow-up was 4 years (range 6 months to 10.7 years). Subjective current knee function averaged 8.0 (range 3.5-10) on a scale of 0-10. Knee pain severity averaged 2.2 (range 0-4) on a scale of 0-10. Pain frequency averaged 3.3 (range 0-9) on a scale of 0-10. Better results were seen in younger patients.

CONCLUSION

Hypermobility of the posterior portion of the lateral meniscus can successfully be treated with arthroscopic repair to the posterior capsule.

LEVEL OF EVIDENCE: IV.