The meniscotibial ligament role in meniscal extrusion: a systematic review and meta-analysis

The meniscotibial ligament (MTL) limits extrusion of the medial meniscus (MM). While meniscal extrusion may be detrimental to knee joint biomechanics, the role of the MTL in meniscal extrusion is debatable. We sought to perform a systematic review and meta-analysis to evaluate the role of the MTL and surgical techniques for MTL repair.

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines we searched PubMed, Cochrane Library, and Embase for: (("Meniscotibial") OR ("Coronary") OR ("Ramp")) AND ("Extrusion"). After screening and applying eligibility criteria, data were extracted for MTL pathology types ("traumatic" ruptures or "induced" injuries) and meniscal extrusion. A meta-analysis evaluated the mean difference of extrusion between "intact" MTLs (native or repaired) and "injured" MTLs (induced or traumatic). We further performed a subgroup analysis between traumatic and induced MTL lesions.

This systematic review included six studies, which all evaluated MM extrusion. There were 74 knees with induced MTL injuries and 19 knees with traumatic MTL ruptures. Study designs were heterogenic and utilized three types of MTL repair procedures. The meta-analysis included 18 human knees and revealed that sectioning the MTL created a 2.92 mm [- 0.18 to 6.03] MM extrusion, while MTL repair decreased MM extrusion by - 2.11 mm [- 3.03 to - 1.21].

MTL injury may result in approximately 3 mm of MM extrusion, while repair of the MTL can decrease extrusion by 2 mm. Several novel surgical techniques exist to repair the MTL. However, studies reporting clinical outcomes of these various procedures are scarce.