Meniscal injury potentiates a sequence of events that leads to degenerative changes and early osteoarthritis. It is therefore imperative to preserve the meniscus whenever possible. Given the expanding indications for meniscus repair, it is important to continually analyze and advance the understanding of rehabilitation and return to play following meniscal surgery. This article presents evidence-based rehabilitation and return-to-play guidelines as well as a brief review of return-to-play outcomes following isolated meniscus repair.
The menisci play an important role in preserving overall joint health, thus preservation is paramount.
Meniscus tear patterns and their associated repair techniques respond differently to physiologic loading, which has a profound influence on rehabilitation strategy.
An ideal meniscal rehabilitation protocol should consider the tear pattern, location, size, quality of the repaired tissue, the type and strength of repair construct, and any concomitant procedures.
There has been increased awareness of the essential role of the knee menisci in protecting the articular cartilage by assisting with shock absorption, load transmission, lubrication, and stability. Injury to the menisci results in altered knee kinematics and increased peak contact stresses, which ultimately accelerates the risk of degenerative changes and early osteoarthritis. Similarly, even partial meniscectomy significantly alters knee stability and joint loading, also leading to increased risk of early articular cartilage degeneration. This information has led surgeons to a recent paradigm shift toward meniscus preservation. Between 2005 and 2011, the number of arthroscopic meniscal repairs in the United States doubled. This trend is multifactorial and likely related to the improved understanding of the importance of the meniscus for overall joint health coupled with major advances in surgical technique and biologic augmentation of meniscal healing.
As surgeons expand their indications for meniscal repair, it is critically important that they continue to analyze and advance their understanding of rehabilitation and return to play following meniscal surgery. There are numerous studies on meniscal repair techniques and their associated outcomes in the literature. However, there is a paucity of high-quality studies evaluating rehabilitation protocols following meniscus repair. Furthermore, there is significant variation between existing postoperative rehabilitation protocols. Despite these limitations, this article summarizes the best available evidence guiding meniscal rehabilitation progression and return-to-play decision making. In addition, it uses the current rehabilitation protocol to help highlight the scientific rationale behind rehabilitation progression and to provide a framework for safe return to activity and sport. This work recognizes inherent limitations in the existing data and discusses areas that are ripe for future collaborative investigation.
Evidence-based Considerations for Meniscus Repair Rehabilitation
Biomechanical studies have shown that the various meniscus tear patterns and their associated repair techniques respond differently when subjected to physiologic loading. For example, weight bearing across the knee helps reduce and compress vertical longitudinal and bucket-handle tears, which may improve healing rates following repair. In contrast, weight bearing causes displacement and distraction of radial, root, and complex tears, which likely decreases the chances of successful healing. As a result, accelerated rehabilitation protocols with early weight bearing and range of motion (ROM) have shown positive results in patients with vertical and more stable tear patterns. Lind and colleagues randomized 60 patients undergoing repair of unstable peripheral vertical meniscus lesions to either an accelerated or conservative postoperative rehabilitation plan. The accelerated plan consisted of 2 weeks of 0° to 90° ROM without a brace and touch-down weight bearing followed by unrestricted weight bearing and ROM. This group returned to running at 8 weeks and contact sports at 4 months. Compared with the restricted group, there were no differences in functional or subjective outcomes at 1 or 2 years. However, there is limited evidence to support these advanced protocols for more complex and unstable tear patterns. Kocabey and colleagues achieved positive results using a tear-specific rehabilitation protocol. Fifty-five patients undergoing a T-fix meniscal repair were stratified according to tear size. Patients with anteroposterior longitudinal meniscal tears less than 3 cm in length were full weight bearing following surgery but ROM was restricted to 0° to 90° for 3 weeks and 0° to 125° from 3 to 6 weeks. Patients with tears greater than 3 cm were immobilized in a knee brace for 3 weeks but allowed weight bearing. Patients were restricted to passive motion from 0° to 90° with a continuous passive motion (CPM) device. Between weeks 3 and 6, patients were allowed to progress to active knee flexion between 0° and 90°. In addition, patients progressed to 0° to 125° for weeks 6 to 8, after which all restrictions were terminated. Patients with complex and radial tears were further limited with respect to initial postoperative weight bearing and ROM (ie, non–weight bearing and no flexion >90° for 6 weeks). Ultimately, patients with longitudinal tears were allowed to return to sport at 3 months, whereas patients with complex and radial tears were allowed to return to sport between 4 and 5 months. The investigators reported that 96% of patients with isolated meniscus repair and 100% with combined anterior cruciate ligament (ACL) reconstruction and meniscus repair showed excellent outcomes. Given these findings, it follows that an ideal protocol must consider the tear pattern, location, and size; quality of the repaired tissue; the type and strength of repair construct; and any concomitant procedures (eg, ligament repair/construction, realignment osteotomy, cartilage restoration) that may have been performed.
The early postoperative period is crucial to protect the meniscal repair such that compression is maintained across the repair site. If the compressive forces across the repair site are lost, the odds of successful meniscal healing decrease significantly. Two main factors are at play with regard to compression at the repair site: (1) the strength and security of the fixation at the time of surgery, and (2) the weight bearing status postoperatively. The quality of the repair construct is under the control of the surgeon and every attempt should be made at anatomic reduction and fixation of the torn meniscus in order to optimize its healing potential and to restore normal knee biomechanics. There has been an evolution of fixation strategies to assist surgeons in achieving this goal. A myriad of all-inside, inside-out, outside-in, and novel suture passers and fixation devices are available for most tear patterns, including meniscal root and ramp lesions. Having a broad arsenal for meniscal repair can assist surgeons in achieving the goal of anatomic reduction and strong time-zero meniscus fixation. In addition, the weight-bearing status is determined both by surgeon preference and patient compliance. Early weight bearing can be helpful to provide compression and reduction in more stable tear patterns, and these patients should be allowed to weight bear as tolerated (WBAT) immediately following surgery. In contrast, weight bearing can create distractive forces for unstable tear patterns, specifically radial, complex, and posterior root tears, and thus these patients should be made non–weight bearing for a period of several weeks ( Fig. 1 ).
It is also important to consider the axial alignment of the patient before advancing weight-bearing status. Previous work has shown that patients with varus deformity are at higher risk of developing atraumatic medial meniscus tears. Therefore, patients with varus malalignment undergoing rehabilitation following a medial meniscus repair may benefit from a more conservation approach to progressive weight bearing. The same principles should be applied to those with valgus alignment undergoing a lateral meniscus repair because of the increased compressive loads in the lateral compartment. These select patients may also benefit from a medial or lateral unloader brace when initiating weight bearing postoperatively to reduce loads across the meniscus repair within the compartment at risk.
In addition to the postoperative weight-bearing status, knee ROM also needs to be carefully considered. It has been shown that immobilization following meniscal repair is detrimental to meniscal healing. Protected early ROM is important for healing and to reduce the risk of postsurgical arthrofibrosis. However, it is imperative to avoid deep flexion given that cadaveric studies have shown greater femorotibial contact pressures in higher degrees of knee flexion as opposed to full extension or low degrees of knee flexion. The progression toward high knee flexion angles during weight bearing leads to higher peak contact pressures, which may be detrimental to meniscal healing, particularly following radial and root repairs. However, these restrictions may not be required following fixation of more stable tear patterns (ie, vertical longitudinal tears). Extrapolating data from the knee cartilage restoration and repair literature, it seems that early gravity-assisted ROM (even past 90°) and/or use of CPM are likely safe and beneficial in the early postsurgical period. Progression to loaded deep-flexion activities should be avoided until meniscus healing is well underway (ie, 3 months) because of the increased loads and translation experienced by the menisci in higher degrees of knee flexion.
Blood Flow Restriction Therapy: A Novel Approach to Quadriceps Atrophy
It is well known that knee pain and effusion can lead to quadriceps dysfunction and atrophy; this is particularly true in the setting of a meniscal tear, both preoperatively and postoperatively. Furthermore, there is likely a correlation between the length of time a patient has a meniscal tear (ie, longer time with painful effusion) and the amount of quadriceps dysfunction and/or atrophy (ie, longer duration of quadriceps avoidance). It has been shown that the return of quadriceps function and strength in the setting of ACL injury and reconstruction is related to improved patient outcomes. However, it can be difficult to restore quadriceps muscle strength and size while protecting a meniscal repair. The American College of Sports Medicine recommends a resistance training load of 70% to 85% of the 1-repetition maximum (1RM) to promote muscle hypertrophy. It is often challenging or impossible for postoperative patients to achieve these loads early in the recovery process while protecting the meniscus, particularly in the setting of complex tear patterns and repairs that require early limitations in weight bearing and ROM. Blood flow restriction therapy (BFRT) has become a growing part of the preoperative and postoperative rehabilitation regimen to combat this difficult problem.
During a blood flow restriction session, a specialized blood pressure cuff is placed on the patient’s extremity ( Fig. 2 ). Most commonly, this is the operative extremity, but it may be used on other extremities as well. The specialized cuff measures the patient’s blood pressure and sets the cuff pressure at a specific level to prevent venous outflow from the patient’s limb, which ultimately results in the development of an anaerobic environment with subsequent release of growth factors. It is the release of these growth factors that promotes muscle hypertrophy. The beauty of BFRT is that it can stimulate an anaerobic environment using loads much less than the traditional 70% to 85% of 1RM, thus minimizing stresses to the meniscal repair. Most studies on BFR use loads near 30% of 1RM, with results showing significant increases in both muscle hypertrophy and strength. Although there are scant data on the use of BFR following meniscal repair, there are encouraging studies in the ACL reconstruction literature proving the safety and efficacy of BFRT. According to a recent meta-analysis, strength and muscle hypertrophy were significantly greater in the groups performing exercise with BFR 2 to 3 d/wk compared with those exercising 4 to 5 d/wk.
In our practice, our physical therapists are certified in BFRT and use it in select patients with complex repairs requiring prolonged weight-bearing limitations. We also use this in our athletic population following standard or complex repairs to accelerate the return of quadriceps function and to help facilitate earlier return to sport. We are actively collecting prospective data on several populations using BFR for rehabilitation following ACL reconstruction (randomized controlled trial enrolling), meniscus repair, and cartilage restoration; and should have data on its efficacy for early quadriceps return and functional outcomes in the near future.
Meniscal repair rehabilitation
This article focuses on isolated meniscal repair in patients with otherwise normal knees. Our guidelines for rehabilitation following meniscal repair are divided into 4 phases. They can be referenced in Tables 1–4 .
|Phase I: Immediate Postoperative/Postinjury Phase (Protected Motion)|
|Frequency||Rehabilitation appointments begin within 10–14 d of surgery and continue 2–3 times per week|
|Cardiovascular Exercises||None at this time|
|Requirements for Progression|
|Phase II: Intermediate Phase (Low Impact)|
|Frequency||Rehabilitation appointments continue 1–3 times per week|
|Cardiovascular Exercises||Swimming (without frog kicking) |
Stationary/level-surface biking without resistance
Elliptical without or minimal resistance
|Requirements for Progression|