Medial Meniscus Transplantation and Bone-Tendon-Bone Anterior Cruciate Ligament Reconstruction

Long-Term Clinical and Radiographic Outcomes of Meniscus Allograft Transplant

PURPOSE OF REVIEW

To reduce pain, improve function and possibly mitigate the risk for development of osteoarthritis in patients with functionally deficient meniscus pathology, meniscal allograft transplantation (MAT) can be used to restore native joint biomechanics and increase knee joint longevity. This review explores the senior author's preferred bridge-in-slot technique and recently published long-term clinical and radiographic outcomes following MAT.

RECENT FINDINGS

Recent literature demonstrates MAT to be a safe and largely successful procedure for patients with functional meniscus deficiency. A majority of patients reach established minimal clinically important difference (MCID) values. Graft survivorship is approximately 80% at 10 years, significantly delaying and in some cases, preventing the need for future joint reconstruction procedures in these young patients. Return to sport rates are over 70%, revealing meniscal allografts can withstand high impact activities. Cartilage damage at the time of MAT increases the risk for graft and clinical failure, though this may be mitigated with a concomitant cartilage restoration procedure. Meniscal allograft transplantation can provide a durable and effective long-term solution to meniscal deficiency in symptomatic patients who wish to decrease the risk of symptomatic progression and possibly further osteoarthritis and continue activities of daily life and sports with less pain and more function. By restoring more normal joint biomechanics, MAT can mitigate the potential need for future knee arthroplasty in this young active patient population.

The Principles of Knee Joint Preservation: Operative Treatment Strategies

➤ Joint alignment, meniscal status, and ligament stability are codependent factors involved in knee joint preservation, and any injury or imbalance can impact the knee articular cartilage status and can result in adverse clinical outcomes.➤ Cartilage preservation procedures in the knee will not result in optimal outcomes if there is joint malalignment, meniscal deficiency, or ligamentous instability.➤ Lower-extremity varus or valgus malalignment is a risk factor for the failure of an anterior cruciate ligament (ACL) reconstruction. It represents an indication for a high tibial osteotomy or distal femoral osteotomy in the setting of failed ACL reconstruction, and may even be considered in patients who have an initial ACL injury and severe malalignment.➤ An elevated posterior tibial slope increases the risk of failure of ACL reconstruction, whereas a decreased posterior tibial slope increases the risk of failure of posterior cruciate ligament reconstruction.

Using Single Peroneal Longus Tendon Graft for Segmental Meniscus Transplantation and Revision Anterior Cruciate Ligament Combined Anterolateral Reconstruction

This case report describes a new approach to segmental meniscal reconstruction using a peroneal longus autograft in a patient with recurrent traumatic medial meniscus tear and anterior cruciate ligament reconstruction (ACLR) failure. While allograft meniscal transplantation is the preferred method for treating meniscal deficiency, its high cost and various legal regulations have limited its widespread use. Autologous tendon grafts have been proposed as a substitute for allograft meniscus transplantation, but their initial results were poor, leading to little progress in this area. However, recent animal experiments and clinical studies have demonstrated promising results in using autologous tendon grafts for meniscal transplantation, including improvements in pain and quality of life for patients. Further research is needed to evaluate the effectiveness of segmental meniscal reconstruction using autologous tendon grafts, but it could potentially lead to more accessible and cost-effective treatment options for patients with meniscal deficiency.

Editorial Commentary: Combined Anterior Cruciate Ligament Reconstruction and Medial Meniscal Transplantation Improve Functional Outcomes When Properly Indicated

The anterior cruciate ligament (ACL) and medial meniscus both contribute to anteroposterior translation of the tibia. Biomechanical studies have found increased translation at both 30° and 90° when transecting the posterior horn of the medial meniscus, and clinically, medial meniscal deficiency has been shown to have a 46% increase in ACL graft strain at 90°. Medial meniscal deficiency is a risk factor for failure after ACL reconstruction, with a hazard ratio of 15.1. The combination of meniscal allograft transplantation and ACL reconstruction is technically demanding but results in mid- to long-term clinical improvement in well-indicated patients. Patients with medial meniscal deficiency and failed ACL reconstruction or with ACL deficiency and medial-sided knee pain due to meniscal deficiency are candidates for combined procedures. On the basis of our experience, acute meniscal injury is not an indication for primary meniscal transplantation in any setting. Surgeons should repair the meniscus if reparable or perform partial meniscectomy and see how the patient responds. There is insufficient evidence to show that early meniscal transplantation will be chondroprotective. We reserve this procedure for the indications previously described. Severe osteoarthritis (Kellgren-Lawrence grades III and IV) and Outerbridge grade IV focal chondral defects of the tibiofemoral compartment that are not amenable to cartilage repair are absolute contraindications to the combined procedure.

Acceptable clinical outcomes despite high reoperation rate at minimum 12-month follow-up after concomitant arthroscopically assisted anterior cruciate ligament reconstruction and medial meniscal allograft transplantation

BACKGROUND

Single-stage medial meniscus allograft transplantation (MAT) with concomitant anterior cruciate ligament reconstruction (ACLR) is a technically challenging procedure for management of knee pain and instability in younger patients, but clinical and functional outcomes data are sparse. The purpose of this study was to assess surgical and patient-reported outcomes following concomitant ACLR and medial MAT.

METHODS

We conducted a retrospective case series of patients who underwent medial MAT with concomitant primary or revision ACLR at our institution from 2010 to 2021 and had minimum 12-month follow-up. Complications, reoperations, visual analog scale (VAS) pain, satisfaction, Lysholm score, return to sport, and return to work outcomes were assessed. Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference, Pain Intensity, and Physical Function Scores were used to measure patients' functional status relative to the US population. P-values < 0.05 were considered significant.

RESULTS

The cohort consisted of 17 knees of 16 individual patients. The cohort was majority male (82.4%) with mean age of 31.9 years (range 19-49 years) and mean body mass index (BMI) of 27.9 kg/m² (range 22.5-53.3 kg/m²). Mean follow-up time was 56.8 months (range 13-106 months). Most patients underwent revision ACLR (64.7%). The 1-year reoperation rate was high (23.5%), with two patients (11.8%) tearing their meniscus graft. Patient-reported outcomes indicated low VAS pain (mean 2.2), high satisfaction (mean 77.9%), and fair Lysholm score (mean 81.1). Return to work rate was high (92.9%), while return to sport rate was low (42.9%). Postoperative PROMIS scores were comparable or superior to the national average and correlated significantly with patient satisfaction (p < 0.05).

CONCLUSIONS

The concomitant ACLR and MAT procedure is associated with excellent knee pain and functional outcomes and high rate of return to work after surgery, though the 1-year reoperation rate is high and rate of return to sport is low.

LEVEL OF EVIDENCE

IV.