Concomitant posterior anchoring further reduces posterior meniscal extrusion during pullout repair of medial meniscus posterior root tears: a retrospective study

Accurate tibial tunnel position in transtibial pullout repair for medial meniscus posterior root tears delays the progression of medial joint space narrowing

PURPOSE

This study aimed to evaluate the association between the progression of medial joint space (MJS) narrowing, medial meniscus extrusion (MME) and clinical scores and the tibial tunnel position in pullout repairs for medial meniscus posterior root tears (MMPRTs).

METHODS

This retrospective study examined 54 patients. Changes in MJS (ΔMJS), MME (ΔMME) and clinical scores and their relationship with the tibial tunnel position were evaluated using correlation coefficients. The distance from the anatomical to technical attachment position in the tibial tunnel position was measured in the anterior and medial directions, and the direct distance was measured using the Pythagorean theorem.

RESULTS

The mean ΔMJS and ΔMME were 0.6 ± 0.8 and 1.3 ± 1.3 mm, respectively, and the mean anterior, medial and direct distances were 1.4 ± 2.3, 2.2 ± 1.7 and 3.4 ± 1.7 mm, respectively. ΔMJS had a significant positive correlation with the medial (r = 0.580, p < 0.001) and direct (r = 0.559, p < 0.001) distances, while ΔMME had a significant positive correlation with direct distance (r = 0.295, p = 0.030). Several clinical scores were significantly negatively correlated with these distances.

CONCLUSION

In transtibial pullout repair for MMPRTs, accurate tibial tunnel position delayed the progression of MJS narrowing and MME, leading to improved clinical outcomes. The progression of MJS narrowing was associated with the mediolateral direction of the tibial tunnel position, while the clinical scores were associated with the anteroposterior direction of the tibial tunnel position. These findings indicate the need to orient the tip of the guide in a more posterolateral direction when creating the tibial tunnel.

LEVEL OF EVIDENCE

Level IV.

Longitudinal changes in medial knee joint space narrowing after medial meniscus posterior root repair: A 2-year follow-up study

BACKGROUND

Despite good clinical results, repair of medial meniscus (MM) posterior root tears (MMPRTs) may not completely prevent knee osteoarthritis progression. This study evaluated changes in the medial joint space (MJS) during the first and second years after repair, compared to narrowing in the contralateral knee, using fixed-flexion view (FFV) radiographs.

METHODS

Fifty-four patients who underwent pull-out repair for a unilateral MMPRT were included. FFV radiographs were obtained pre-operatively and at the 1- and 2-year post-repair timepoints to evaluate changes in the MJS and Kellgren-Lawrence grade bilaterally. Clinical outcomes were also evaluated.

RESULTS

The change in the MJS was greater in MMPRT knees than in contralateral knees during the first year (0.48 ± 0.80 mm vs. 0.09 ± 0.49 mm, p < 0.001), but this difference lessened in the second year (0.09 ± 0.36 mm vs. 0.07 ± 0.38 mm, p = 0.285). Kellgren-Lawrence grade progression in MMPRT knees was less in the second year. Clinical outcomes significantly improved at both 1 and 2 years post-repair than the pre-operative values (p < 0.001), with continued improvement in clinical outcomes in the second year. There was no significant correlation between patient characteristics and the change in the MJS from preoperatively to 2 years postoperatively.

CONCLUSION

Pull-out repair for MMPRTs did not completely prevent MJS narrowing, but the rate of narrowing decreased in the second year (mean, 0.09 mm) compared to that in the first year (mean, 0.48 mm). MJS narrowing in the second year after MM posterior root repair was comparable to that of the contralateral knee. Clinical outcomes further improved over the second year after repair.

LEVEL OF EVIDENCE

IV.

Meniscal Extrusion: Diagnosis, Etiology, and Treatment Options

PURPOSE OF REVIEW

The concept of meniscal extrusion has recently been recognized as a hallmark of meniscus dysfunction. This review examines contemporary literature regarding the pathophysiology, classification, diagnosis, treatment, and future directions for investigation regarding meniscus extrusion.

RECENT FINDINGS

Meniscus extrusion, defined as >3 mm of radial displacement of the meniscus, leads to altered knee biomechanics and accelerated knee joint degeneration. Meniscus extrusion has been associated with degenerative joint disease, posterior root and radial meniscal tears, and acute trauma. Meniscus centralization and meniscotibial ligament repair have been proposed as techniques to address meniscal extrusion with promising biomechanical, animal model, and early clinical reports. Further studies on the epidemiology of meniscus extrusion and associated long-term nonoperative outcomes will help to elucidate its role in meniscus dysfunction and resultant arthritic development. Understanding and appreciation for the anatomic attachments of the meniscus will help to inform future repair techniques. Long-term reporting on the clinical outcomes of meniscus centralization techniques will yield insights into the clinical significance of meniscus extrusion correction.