Fixation Methods and Treatment Choices for Medial Meniscus Posterior Root Tears (2)

At present, the final outcome cannot be judged simply by whether the technique uses an anchor or a bone tunnel.

Comparative data have found that both transtibial pull-out fixation and suture anchor fixation can improve knee function and pain, with no obvious difference between groups in some clinical measures and MRI healing results. At the same time, some biomechanical tests have found that anchor fixation may allow less root displacement under cyclic loading.

For patients, the more practical questions are whether the tear pattern is repairable, whether the meniscus can be returned to its anatomic position, how severe the cartilage damage is, whether marked meniscal extrusion exists, whether limb alignment is normal, and how familiar the surgeon is with the selected technique.

Therefore, the surgical method is usually chosen according to the specific condition of the knee. Current evidence is not strong enough to prove that one fixation method applies to every patient.

After a posterior root tear, the meniscus often shifts outward beyond the tibial plateau, which is called meniscal extrusion. In some patients, extrusion may persist even after the root has been repaired.

This is why meniscal centralization has attracted attention in recent years. Centralization further pulls the extruded meniscal body back toward the edge of the tibial plateau and fixes it there, aiming to improve coverage of the joint surface.

For patients with marked extrusion, it remains uncertain whether isolated root repair can fully restore meniscal function. Adding centralization may reduce extrusion and tension at the repair site, but case numbers and long-term follow-up remain limited.

Varus alignment means that more body weight passes through the medial side of the knee. Even if the posterior root is repaired, persistent abnormal loading may continue to place high stress on the repair area.

For patients with clear varus alignment, doctors may also evaluate high tibial osteotomy (HTO). This operation adjusts lower-limb alignment and shifts part of the load away from the damaged medial compartment.

For some patients with varus alignment greater than about 5 degrees combined with a posterior root tear and meniscal extrusion, a combination of root repair, centralization, and HTO may be considered. Whether osteotomy is needed depends on full-length lower-limb X-rays, cartilage damage, age, and activity demands.

After posterior root repair, sutures provide only the initial mechanical fixation. True stability requires gradual healing between the meniscus and its tibial attachment area. Early rehabilitation therefore usually restricts weightbearing and deep knee flexion.

One common protocol uses a brace early and avoids weightbearing on the operated limb, then gradually increases range of motion and load. In the 2025 series of 29 cases, patients wore a brace and avoided weightbearing for the first 4 weeks; after week 4, flexion angle and weightbearing were gradually increased; from week 6, full weightbearing and progressive restoration of full range of motion began, while deep squatting was still avoided later.

Other protocols may require about 6 weeks of non-weightbearing and limit high-flexion angles early. The exact pace of rehabilitation should be set according to fixation method, tissue quality, and intraoperative judgment. Patients should not independently return early to deep squatting, running, or sport.

Posterior root repair cannot guarantee complete meniscal healing, nor can it guarantee that existing osteoarthritis will stop progressing. Recurrent tear, persistent meniscal extrusion, fixation failure, and incomplete symptom relief may occur.

Patient factors also influence results. Marked varus alignment, more severe cartilage degeneration, higher BMI, and older age may be associated with poorer healing and long-term outcomes.

Current comparisons between fixation methods remain limited. Much of the evidence comes from retrospective series, small samples, or biomechanical tests, and follow-up durations are inconsistent. Inverted anchors, centralization, and biologic augmentation have potential, but longer-term data are still needed to determine whether they further reduce osteoarthritis progression and knee replacement risk.

If MRI suggests a medial meniscus posterior root tear, four issues should be clarified: the degree of cartilage wear, whether meniscal extrusion is marked, whether there is significant varus alignment, and whether the torn tissue remains repairable.

For patients with better cartilage condition, a reducible tear, and mild osteoarthritis, posterior root repair can be an important treatment option. Transtibial fixation and anchor fixation each have appropriate indications, and the technique should be chosen according to anatomy and surgeon experience.

For patients with advanced osteoarthritis, clear lower-limb malalignment, or poor repair conditions, treatment may need to focus on reducing medial compartment load, relieving pain, and maintaining joint function. Seeing the words medial meniscus posterior root tear on an MRI report alone is not enough to decide whether surgery is needed or which fixation method should be used.