An isolated Posterolateral corner injury with rotational instability and hypermobile lateral meniscus: a novel entity

Hypermobile lateral meniscus: A systematic review of current treatment options

PURPOSE

The reliable data on the incidence of hypermobile lateral meniscus (HLM) and its clinical manifestations, diagnostic methods and therapeutic approaches are limited. This systematic study aimed to review available treatment options for HLM and the outcomes of each approach.

METHODS

A systematic search was performed in four electronic databases (PubMed, EMBASE, Scopus, Web of Science) to identify studies in which arthroscopically confirmed cases of HLM were treated surgically or nonsurgically, and the required data comprising study characteristics, patient data, treatment approaches and outcome measures were extracted from eligible studies.

RESULTS

Twenty studies with a total of 212 patients (138 males and 74 females) and 219 knees were included. The most frequently reported symptoms were locking sensations, knee pain, giving way and snapping. Treatments used by the studies were: radiofrequency energy in two studies; arthroscopic partial meniscectomy in one study; open surgery in two studies; and arthroscopic meniscal repair in 17 studies. Eleven studies used an all-inside repair method and an inside-out meniscal repair was reported in eight studies. Three studies reported the usage of posterior arthroscopy for therapeutic or diagnostic approaches. Evaluation of symptom resolution was the main outcome measurement for which almost all of the studies stated relief of symptoms after intervention.

CONCLUSION

Despite the lack of definite consensus about the most appropriate intervention for HLM, therapeutic preference was directed towards arthroscopic all-inside and inside-out repair techniques. Although the surgeon's decision remains the key factor in choosing the most suitable treatment option for each individual, posterior arthroscopic meniscal repair may be considered as a better option for HLM treatment according to the findings of this review.

LEVEL OF EVIDENCE

Level IV.

Reinsertion of Posterior Meniscal Root for Management of Hypermobile Lateral Meniscus: Description of a Surgical Technique

Lateral meniscus hypermobility is a special condition in which the posterior horn of the lateral meniscus exhibits excessive mobility. This condition can cause pain and locking in the knee, especially during kneeling, deep flexion, or squatting. In this article, we present a surgical technique for the reinsertion of the posterior root of the external meniscus in cases of hypermobility without detachment. The objective is to increase the tension of the meniscotibial and meniscal popliteal ligaments to achieve meniscal stability. The procedure involves suturing the meniscal root and fixation using a knotless implant through a transosseous tunnel. This technique has proven to be effective in stabilizing the lateral meniscus in patients with hypermobility.

Rehabilitation and return to sports after isolated meniscal repairs: a new evidence-based protocol

PURPOSE

Despite many protocols that have been proposed, there's no consensus in the literature regarding the optimal rehabilitation program and return to sports (RTS) protocol following isolated meniscal repair. The aim of this current concept review is to look at the evidence of rehabilitation and RTS program after isolated meniscal repair, focusing on general and specific protocols per type of injury trying to give some guidelines based on the current state of knowledge.

METHODS

A narrative literature review was performed searching PubMed database to identify relevant articles from January 1985 to October 2021 on rehabilitation and RTS after isolated meniscal repair. Randomized controlled trials (RCTs), prospective and retrospective cohort studies, case series, systematic reviews, meta-analyses, cadaveric studies and basic science studies were included.

RESULTS

When the hoop tensile stress effect is preserved, an accelerated rehabilitation program may be suggested. Hence, partial weight bearing (20 kg) in association with ROM limited to 90° is allowed for the first four weeks, followed by weight bearing as tolerated. In contrast, when circumferential hoop fibers are disrupted, a restricted rehabilitation protocol may be recommended. In this scenario no weight bearing is allowed for the first six weeks after the surgery and range of motion (ROM) is limited to 90°.

CONCLUSION

Biomechanical evidence suggests that tailoring an individualized protocol based upon the type of lesion and meniscus stability is reasonable.

LEVEL OF EVIDENCE

Level V.

The hypermobile and unstable lateral meniscus: a narrative review of the anatomy, biomechanics, diagnosis and treatment options

Objective

The purpose of this review is to improve the awareness of lateral meniscal hypermobility by describing its relevant anatomy, biomechanics, pathophysiology, imaging and arthroscopic findings as well as the treatment options.

Background

The lateral meniscus is less stable than the medial meniscus. Its important posterior stabilizers are the popliteomeniscal fascicles, the posterior capsule, the meniscofemoral ligaments and the posterior meniscotibial ligament, which are divided by a bare area, the popliteal hiatus. Atraumatic insufficiency or rupture of one of these key structures may impact the mobility of the lateral meniscus and can lead to an unstable, hypermobile lateral meniscus. Lateral meniscus hypermobility can cause lateral knee pain and mechanical symptoms as locking. Ruptures of the popliteomeniscal fascicles are frequently associated with anterior cruciate ligament and posterolateral corner injuries. Their repair may be important to fully restore knee stability.

Methods

This is a narrative overview of the literature synthesizing current knowledge about the hypermobile lateral meniscus. Anatomy, biomechanics, diagnosis and treatment of this entity was of particular interest for this review. Literature was retrieved from PubMed database, hand searches and cross-reference checking.

Conclusions

Diagnosing lateral meniscus hypermobility is challenging since the magnetic resonance imaging are often unspecific and may show no structural alterations of the meniscus and its attachments. The only hint can be the patient's history and clinical symptoms (e.g., locking). Ultimately, the diagnosis is confirmed during knee arthroscopy, when the lateral meniscus can be mobilized over 50% of the lateral tibial plateau or lateral femoral condyle while anterior probing or by using the aspiration function during arthroscopy. Treatment includes stabilizing the posterior lateral meniscus by repairing the injured structures. Therefore, a systematic arthroscopic evaluation of the lateral compartment is important to fully recognize the problem. Repair can be achieved arthroscopically with various suturing techniques used for meniscal repair with satisfactory results and low recurrence rates.

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

PURPOSE

Anterior 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.

METHODS

A 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.

RESULTS

In 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).

CONCLUSION

Careful 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 EVIDENCE

II.