Evaluation of healing after arthroscopic repair of lateral meniscal tears around the popliteal hiatus.

Background: The popliteal hiatus stabilizes the lateral meniscus (LM). Variable failure rates for LM repairs have been reported in knees with lateral meniscal tears (LMTs), which may be attributable to low vascularity around the popliteal hiatus. An effective repair method is essential to enhance the biological healing and stability of LMTs around the popliteal hiatus.

Hypothesis: Arthroscopic repair of LMTs, including the popliteus tendon around the popliteal hiatus, is expected to produce a low reoperation rate and effective treatment, both clinically and radiographically.

Material and methods: From June 2011 to August 2020, 93 patients (mean age 27.9 ± 13.5 years) who underwent arthroscopic repair of LMTs including the popliteus tendon around the popliteal hiatus were enrolled. Patients with LMTs were divided into three groups: isolated LMTs, discoid LMTs, and LMTs with ACL injury. Patients had a minimum clinical follow-up of 2 years (mean 37.9 ± 19.3 months) and Tegner activity, Lysholm knee, and Hospital for Special Surgery (HSS) scores were evaluated for all patients. The widths of the popliteal hiatus and LM extrusion were measured on the sagittal and coronal planes using preoperative and postoperative magnetic resonance imaging (MRI).

Results: The Tegner activity (2.6 ± 1.2-4.5 ± 1.3), Lysholm (67.9 ± 14.2-88.1 ± 6.4), and HSS scores (79.8 ± 11.5-93.7 ± 5.1) were significantly improved in all knees (p < 0.001). The width of the popliteal hiatus measured on MRI was significantly decreased, when comparing the preoperative and postoperative MRI for all knees (sagittal plane, 2.9 ± 1.4-1.5 ± 0.5 mm; coronal plane, 3.8 ± 2.5 to 1.9 ± 1.0 mm) (p < 0.05). The LM extrusion measured on the sagittal plane of postoperative MRI was also significantly reduced after arthroscopic repair (24.8 ± 3.1-23.7 ± 2.8 mm) (p = 0.001). Five reoperations (5/93, 5.3%) were performed, suggesting a clinical failure.

Conclusion: Arthroscopic repair of isolated, discoid and post-traumatic LMTs including the popliteus tendon around the popliteal hiatus, is an effective surgical treatment for LM stabilization.

Level of evidence: Level IV, retrospective series.