Comparison of Isolated Meniscus Repair Versus Combined Meniscus Repair and Notch Microfracture: A Randomized Controlled Trial Evaluating Functional and Imaging Outcomes

Meniscal tears are the most common injury among musculoskeletal injuries. The incidence rate has varied across different studies in Europe, with a mean incidence of 60 to 70 per 100,000 annually. Despite advanced meniscal repair techniques, the failure rates are still 20-24% within two years, rising to 26% in medial tears.

Outcomes improve significantly when repair is combined with ACL reconstruction, where healing rates increase up to 93%, likely due to the biologically enriched environment created by bone tunnels and associated release of growth factors. The microfracture technique reproduces this environment by making small channels in the intercondylar notch of the femur that release marrow-derived factors to enhance healing.

Retrospective studies have been undertaken comparing the two repair methodologies. However, prospective comparative studies have not yet been explored in human populations.

This study aims to compare the functional and imaging outcomes of meniscus repair with notch microfracture in comparison with meniscal repair alone through a randomized controlled trial.

Although meniscal preservation is considered essential for long-term knee function, isolated repairs continue to show high failure rates. Evidence of superior outcomes when repair is combined with ACL reconstruction highlights the importance of a biologically enriched intra-articular environment. Microfracture replicates this environment by releasing stem cells and growth factors into the joint.

The meniscus is a C-shaped fibrocartilaginous structure located between the femur and the tibia, with medial and lateral components that serve as stabilizers and shock absorbers of the knee joint. Their main functions include distributing compressive forces to reduce friction during movement, contributing to static load bearing, and assisting with lubrication, stabilization, and proprioception [8].

Meniscal tears may be either traumatic or degenerative. Traumatic tears typically result from twisting injuries and are often associated with sports that involve pivoting and knee flexion. These injuries may present with delayed swelling, pain during deep flexion or twisting, and, in the case of bucket-handle tears, mechanical locking of the knee.

Degenerative tears are more common in older individuals, particularly males and those engaged in occupations requiring frequent kneeling, squatting, or climbing. They usually present with intermittent swelling and chronic knee pain.

Prevalence is higher in men compared to women, with reported male-to-female ratios ranging from 2.5:1 to 4:1. This ratio increases with age, particularly in individuals over 40 years. The medial meniscus is affected far more frequently than the lateral, accounting for approximately 81% and 19% of cases, respectively.

Several criteria are used to classify meniscal tears, guiding management strategies. Etiology distinguishes traumatic from degenerative tears, the latter being less suitable for repair. Circumferential location is based on vascular zones, with the avascular white-white zone, the intermediate red-white zone, and the highly vascular red-red zone; healing potential is greatest in the red-red zone. Radial location-anterior horn, posterior horn, or body-affects both presentation and treatment. Tear patterns are also categorized as vertical-longitudinal, bucket-handle, horizontal, flap, radial, or complex.

Management of meniscal tears depends on factors such as tear complexity, symptom severity, surgical risk, and patient characteristics. Conservative treatment, including rest, nonsteroidal anti-inflammatory drugs, physiotherapy, bracing, and strengthening, is commonly indicated for degenerative or minimally symptomatic tears. Randomized controlled trials have shown no significant long-term difference between exercise therapy and arthroscopic partial meniscectomy (APM), supporting exercise-based therapy as a reasonable first-line option. Meniscectomy, once widely practiced, is now mainly limited to non-repairable tears that remain symptomatic after at least three months of conservative management. Total meniscectomy is avoided because of its strong association with early osteoarthritis, while APM provides limited long-term benefit, especially in degenerative tears. In contrast, meniscal repair has become the preferred option for repairable tears, particularly those in the red-red or red-white zones, as preservation of meniscal tissue is essential to slow the progression of osteoarthritis and maintain long-term joint function.

Adjunctive biological techniques have also been investigated to enhance healing. The microfracture technique involves creating 1-3 mm channels in the intercondylar notch of the femur, allowing the release of marrow-derived stem cells and growth factors into the joint. This process mirrors the favourable environment observed during ACL reconstruction, where bone tunnel formation promotes hemarthrosis and fibrin clot development. Early studies indicate that adding microfracture to meniscal repair may improve outcomes without increasing complications, suggesting potential benefits over isolated repair alone.

Three principal techniques are used in meniscal repair: the outside-in method, in which sutures are passed from outside the joint and tied externally, achieving success rates of around 86% but carrying risks of wound complications and neurovascular injury; the inside-out method, where sutures are passed from inside the joint outward, with reported success rates of 80-100% but a risk of nerve injury and stiffness; and the all-inside method, which avoids additional incisions by placing sutures entirely within the joint, with success rates of 80-93% but potential risks including neurovascular injury, cyst formation, or stiffness.

Methodology

• Type of Study: Randomized Controlled Trial (RCT)
• Study Setting: Ain Shams University Hospitals
• Study Period: Starting after approval of the IRB extending to one year.
• Study Population: Adults of both genders with meniscus tear indicated for repair.

Inclusion criteria

• Isolated Lateral or Medial repairable meniscus tears
• Vertical Longitudinal meniscal tears.
• Adults aged 18-50 years-old
• Both Genders

Exclusion criteria

• Associated ligament injury.
• Associated bone angular deformity.
• Associated chondral injuries that require cartilage reconstruction procedures (microfracture, osteochondral graft or autologous chondrocyte implantation).
• Meniscal tears that occurred more than 6 months before the procedure.

Sample Size 30 adults of both genders to be allocated to both repair methodologies.

Ethical Considerations Approval of the IRB, Faculty of Medicine Ain Shams University will be obtained prior to starting the study. Consent from the patient will be obtained for the whole postoperative follow-up process. However, no sensitive personal details about the patients will be shared to maintain the anonymity of the study.

Study Tools

• International Knee Documentation Committee (IKDC) Evaluation Form
• Lysholm Evaluation Form
• Knee Plain Xray
• Knee Magnetic Resonance Imaging (MRI) Study Process Preoperative Patients will be randomly allocated to either the repair group without microfracture or the group with both repair and microfracture. Randomization process will be done through a computer-system based approach for every case preoperatively.

Preoperatively, a detailed patient history will be obtained, and the IKDC and Lysholm evaluation forms will be completed. A thorough knee examination will then be performed, including inspection, palpation, assessment of knee range of motion (ROM), gait evaluation, and specific diagnostic tests. The special tests to be conducted include:

• Anterior and posterior drawer tests
• Lachman test
• Varus and valgus stress tests
• McMurray test
• Joint line tenderness

Preoperative imaging will be performed for all patients and will include:

• Standing bilateral knee plain radiographs
• MRI scan of the injured knee

Surgical technique Patients will undergo the arthroscopic meniscus repair under either general or spinal anaesthesia. The principal meniscal repair technique will be outside in suturing. For the microfracture group, a 5mm diameter awl will be used to create microfracture holes with a 3-4mm depth penetrating the subchondral bone of the intercondylar notch.

Postoperative care

In the first 6 weeks, patients will be asked to follow this rehabilitation program:

• Weightbearing with knee brace locked in extension
• Knee range of motion is restricted from 0-90 degrees
• Follow quadriceps strengthening exercises From 6 to 12 weeks patients can start full weightbearing without knee brace to restore normal gait. Full knee range of motion can be restored. Patients will be asked to continue the quadriceps strengthening exercises.

At 3 month post operation, functional outcomes will be evaluated using the Lysholm and IKDC evaluation forms.

At 6-month postoperative both functional and imaging outcomes will be evaluated. Similar to the 3 month evaluation, the Lysholm and IKDC evaluation forms will be used to assess functional outcomes.

As for the imaging outcomes, they will be compared through an MRI Scan of the knee. The following is the criteria to confirm whether there is healing or not:

• A change in the intra-meniscal signal intensity.
• A reduction in tear gap
• A change in the signal morphology.

Inclusion criteria

• Isolated Lateral or Medial repairable meniscus tears
• Vertical Longitudinal meniscal tears.
• Adults aged 18-50 years-old
• Both Genders

Exclusion criteria

• Associated ligament injury.
• Associated bone angular deformity.
• Associated chondral injuries that require cartilage reconstruction procedures (microfracture, osteochondral graft or autologous chondrocyte implantation).
• Meniscal tears that occurred more than 6 months before the procedure.