ABSTRACT
BACKGROUND: Most cases of bicruciate knee dislocation (KD) with associated posteromedial disruption (KD-IIIM) are reducible, but some cannot be reduced by closed reduction because of soft tissue incarceration. PURPOSE: To compare the clinical characteristics and functional outcomes of KD-IIIM injuries in patients with or without incarceration of soft tissue requiring open or arthroscopic reduction. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This retrospective cohort study of patients with KD was conducted between January 2013 and December 2017 at a single large institution. We applied a 1:2 matching ratio between patients with irreducible KD-IIIM injuries (irreducible group; n = 14) and those with reducible KD-IIIM injuries (control group; n = 28). There were 13 patients in the irreducible group and 25 in the control group who completed follow-up (≥2 years) and were included in our analysis. The efficacy of treatment in patients with KD was evaluated based on range of motion, the Tegner score, the Lysholm score, and the International Knee Documentation Committee (IKDC) score. RESULTS: At the end of follow-up, the mean Tegner score was 4.5 (range, 4-6), the mean Lysholm score was 79.2 (range, 60-95), and the mean IKDC score was 78.6 (range, 60.9-95.4) in the irreducible group. The respective results in the control group were 4.6 (range, 3-8), 83.1 (range, 39-100), and 80.6 (range, 42.5-96.6). These scores did not differ significantly between the 2 groups. Similarly, mean range of motion was similar between groups (irreducible, 118.1°; control, 124.8°). In the irreducible group, the acute subgroup showed significantly higher Lysholm and IKDC scores than the chronic subgroup, while the acute and chronic subgroups in the control group showed no significant differences in these respective outcome scores. CONCLUSION: In the present study, the treatment of irreducible KD led to similar functional outcomes compared with reducible KD. However, the treatment of chronic irreducible KD led to worse outcomes compared with acute irreducible KD, and therefore, urgent reduction is recommended in these patients.
ABSTRACT
PURPOSE: To compare the clinical, imaging, and arthroscopic characteristics of the torn discoid lateral meniscus (TDLM) in patients greater than 40 years of age with matched controls. METHODS: One hundred and ninety-four older patients (211 knees) who underwent arthroscopic surgery for a TDLM were consecutively recruited (Group 1). Another 211 age- and sex-matched controls with a torn semilunar lateral meniscus were included in this study (Group 2). Statistical analyses were used to determine the differences in the clinical, imaging, and arthroscopic characteristics between the two groups. RESULTS: In our series, more severe medial meniscal extrusion on magnetic resonance imaging was present in Group 1 than in Group 2 and more serious osteoarthritic changes were observed in both the medial and lateral compartments in Group 1. Under the same conditions, chondral lesions in the knee were more serious in Group 1 than in Group 2 when patients were subgrouped according to the presence of a horizontal tear or complex tear. CONCLUSIONS: In the present study, older patients with a torn discoid lateral meniscus exhibited greater and more severe medial meniscal extrusion and more serious osteoarthritis. Therefore, knees with a discoid lateral meniscus displaying medial meniscal extrusion should be monitored carefully with long-term follow-up, because a medial meniscal extrusion may increase the risk of progression to degenerative osteoarthritis of the medial compartment. Regarding the clinical relevance, these findings will be helpful in further revealing that a torn discoid lateral meniscus may affect not only the cartilage in the lateral compartment but also the cartilage in the medial compartment and medial meniscal extrusion. LEVEL OF EVIDENCE: III.
