The aspiration test reveals an instability of the posterior horn of the lateral meniscus in almost one-third of ACL-injured patients

Christophe Jacquet,Matthieu Ollivier,Jacques Menetrey,Romain Seil,Caroline Mouton,Amanda Magosch,George A Komnos

doi:10.1007/s00167-021-06806-2

Abstract

PurposeAnterior cruciate ligament (ACL) injuries often lead to associated injuries of the posterior horn of the lateral meniscus (PHLM). Arthroscopic, assessment of PHLM instability may be difficult in the absence of a visible meniscus damage. The main objective of this prospective multi-center study was to compare the ability of the probing and aspiration tests to identify PHLM instability in a population of patients undergoing ACL reconstruction (ACLR) and a control group of patients with an intact ACL undergoing knee arthroscopy.MethodsA prospective case–control analysis was performed in three sports medicine centers. One-hundred and three consecutive patients operated for a primary isolated ACLR without structural lateral meniscus damage other than a root tear were included. They were compared to a control group of 29 consecutive patients who had a knee arthroscopy with an intact ACL and no structural lateral meniscus lesion. The probing and aspiration tests were consecutively executed according to previously published methods.ResultsIn the control group, no lateral meniscus lesions were visualized during arthroscopy, and both probing and aspiration tests were negative in all patients. In the group of ACL-injured patients, a Forkel type I–III posterolateral meniscus root tear (PLMRT) was found in 12 patients (12%). In this subgroup, the probing test was positive in 4/12 patients (33%) and the aspiration test in 5 additional patients (75%). In 15 patients (15%), an elongation of the posterior root of the lateral meniscus (defined as type IV PLMRT as an addendum to the Forkel classification) could be observed during arthroscopy. In this subgroup, only 1 patient displayed a PHLM instability with the probing test (7%), whereas the aspiration test was positive in 13/15 patients (87%). In the remaining 76 patients (74%), no structural lesion of the PHLM could be identified. Nevertheless, an instability of the PHLM could be identified in 8 of them (11%) with the probing test, and the aspiration test was positive in 2 additional knees (13%) of this apparently normal subgroup. Altogether, in the entire ACL injury cohort, a positive probing test was observed in 13/103 patients (13%) and a positive aspiration test in 32/103 knees (31%) (p < 0.01).ConclusionCareful observation and examination of the PHLM with the aspiration test revealed a substantial amount of previously undiagnosed lateral meniscus instabilities in ACL-injured knees. The prevalence of PHLM instability as evaluated by the aspiration test was high (31%). The aspiration test was superior to the probing test in detecting an instability of the PHLM in a population of ACL-injured patients.Level of evidenceII.

Highlights

Materials and methodsThe anatomy of the lateral meniscus is more complex than on the medial side [11]
Damage to one or several of these structures can result in an instability of the posterior horn of the lateral meniscus (PHLM) which may occur either in isolation or in association with an anterior cruciate ligament (ACL) injury
In the control group the probing and aspiration tests were negative and the lateral meniscus appeared normal under arthroscopy in all patients

Summary

Materials and methods

The anatomy of the lateral meniscus is more complex than on the medial side [11]. This is due to complex posterior suspensory structures including the popliteomeniscal fascicles (PMF) and the posterior meniscotibial ligament (MTL) [2, 7, 19], as well as the posterior root and the meniscofemoral ligament which is made of a meniscotibial and a meniscofemoral fixation [3]. Damage to one or several of these structures can result in an instability of the posterior horn of the lateral meniscus (PHLM) which may occur either in isolation or in association with an anterior cruciate ligament (ACL) injury. A classic anterior view with an antero-medial portal with the knee held in a figure-of-4 position was performed It allowed direct visualization of the chondral status for both the lateral tibial plateau and the lateral femoral condyle using the ICRS classification [4], the lateral meniscus, its posterior root, and the meniscofemoral ligaments. Based on the proportion of negative probing test/positive aspiration test (no event–event) of 10% and the proportion of positive probing test/negative aspiration test (event–no event) of 1%, a minimum sample size of 104 patients was required

Results

Discussion

Conclusion