Summary

The study demonstrates that many patients with repairable meniscal root tears do not present with classic symptoms or signs of meniscal root tears.

Abstract

Objectives:
The posterior root of the medial meniscus plays an important role in cartilage preservation by dissipating forces through hoop stresses, while preventing extrusion of the meniscus. Root tears are clinically significant because the joint reactive forces experienced by the articular cartilage increase substantially with extrusion related to a root tear. Unfortunately, root tears can be difficult to diagnose. Traditional mechanical symptoms of meniscal pathology may not be present. Therefore, obtaining a thorough patient history can provide valuable information that can assist with the diagnosis. The purpose of this study is to analyze the presenting symptoms and clinical exam findings of patients undergoing meniscal root repairs to aid physicians in diagnosing this injury.

Methods

All patients undergoing arthroscopic meniscal repair from 1/1/2016-9/1/2021 were retrospectively identified at our institution using CPT codes, and patients who had definitive documentation of an isolated meniscal root repair within the operative report were included in the study. Patients under the age of 40 years were excluded. Physician clinical notes were reviewed, recording detailed information regarding the presenting symptoms and physical exam findings. Pre-operative radiographs were graded using the Kellgren-Lawrence (KL) scale for osteoarthritis. When available, pre-operative MRIs were evaluated. Root tears were graded using the radiographic criteria of Chung et al. and articular cartilage injury was graded using a validated system, AMADEUS (mean total Area Measurement And DEpth & Underlying Structures, a scale from 0 to 100; 100 = no injury).

Results

There were 221 patients who met the inclusion criteria. Of the 221 patients, 65.6% of patients reported that their pain began following an acute injury, with only 39.3% of patients reporting a “pop.” Only 7.7% reported an injury while walking downstairs, and 76.4% of patients were able to bear weight after the injury. On physical exam, effusion was present in 71% of knees. A McMurray test was positive in 95.5% and a positive hyperflexion test in 53.8% of knees. Radiographically, 49.5% of knees were KL 1, 29.7% were KL 2, and 17.7% were KL 3. There were 118 MRIs available for review. There was a full thickness root tear in 53.3% and partial thickness tear in 35.6% of patients. Regarding the location of the tears, 44.1% of tears occurred at the midsubstance of the root, with 28.0% occurring at the enthesis and 28.0% occurring at the root-posterior horn junction. The mean AMADEUS score was 94.4 ± 11.4.

Conclusion

The study demonstrates that many patients with repairable meniscal root tears do not present with classic symptoms or signs of meniscal root tears. Only 40% of patients reported feeling a “pop” and most patients were able to bear weight following the initial injury. There was an effusion and a positive McMurray test in the vast majority of meniscal root tears. The locations of the root tears were variable, but in our cohort over half of patients had a full thickness tear. A low index of suspicion is necessary to appropriately diagnose and ultimately treat repairable meniscal root tears.