Meniscal injuries in athletes present a challenging problem. Surgeons must balance the needs of the healing meniscus with the desire of the athlete to return to play as quickly as possible. Evidence-based rehabilitation protocols are important for ensuring a successful meniscal repair and preventing athletes from returning to play prematurely. Ultimately, however, the return to play determination requires a shared decision-making approach between the physician, the athlete, and the providers involved in the athlete’s rehabilitation process. This decision considers not only the athlete’s ability to meet return-to-play criteria but also their season-specific and career goals.
Meniscal repair can be performed in an attempt to preserve meniscal tissue in situations whereby there is viable tissue with satisfactory healing potential, because partial or total meniscectomy has been shown to increase knee cartilage degeneration in younger athletes.
The decision of when the athlete can RTP should become a shared decision-making process including all parties of interest, and ultimately, these decisions will be individualized to each athlete.
Timing of return to play is dependent on many factors including the type of tear sustained, prescence of concomitant injuries and the type of repair performed, postoperative rehab protocol, time of season and type of sport played.
RTP rates following meniscal repairs in athletes are reassuring with 80% to 95% of athletes returning to play with the average RTP time being 4 to 6 months.
Introduction and epidemiology
The knee menisci are semicircular, fibrocartilaginous structures that serve several important roles in normal knee function, including load transmission, shock absorption, and secondary stabilization of the knee. The vascular supply of the meniscus has been well studied, with the vascularized peripheral 30% known as the red-red zone and the relatively avascular inner aspects known as the red-white and white-white zones. Tears of the meniscus are common knee injuries in the young, athletic population and are particularly prevalent in contact and pivoting sports. The overall incidence of meniscus tears requiring surgery is 60 to 70 per 100,000 person-years. Ultimately, the decision to pursue surgery for a meniscus tear is complex and multifactorial. Although there may be incentive to manage these injuries without surgery for an in-season athlete, the presence of persistent pain and inability to return to a high athletic level may ultimately push toward operative management.
With operative management, significant effort should be made to preserve viable meniscal tissue. Isolated meniscectomy should be reserved for scenarios in which there is nonviable tissue or there is a nonsatisfactory healing potential, because this may ultimately require an additional surgery and further delay of return to play (RTP). It is essential for the surgeon to manage expectations of both the patient and the athletic training staff with regard to meniscal surgery. Recent studies have shown that return to play times vary dramatically based on the surgical procedure performed and range from as little as 7 to 9 weeks with isolated meniscectomy to 5.6 months with meniscal repair. Both the patient and the athletic training staff must be aware of these expected recovery times and for the potential to take a shorter or longer time depending on the specific athlete.
The authors present a review of the factors influencing RTP following meniscus repair surgery. Rehabilitation protocols following meniscus repair surgery are discussed followed by RTP timing, outcomes, and future considerations.
Meniscal repair in the athlete
Preservation and restoration of meniscal function and normal knee kinematics are of utmost importance in athletes sustaining knee injuries. If not managed appropriately, meniscal injuries in athletes can devastate careers and may accelerate the rate of degenerative changes of the knee joint. Managing meniscal injuries in athletes can be extremely difficult given the significant pressure from the athlete, coaches, parents, and athletic trainers to get the athlete back to play as soon as possible. Physicians must have a sophisticated understanding of the implications of each treatment type, the type of sports played by the athlete, the natural history of these injuries, and milestones that must be met before RTP. Understanding these principles will allow the provider to balance rapid RTP with the risk of premature return and subsequent failed repair or reinjury. The decision of when the athlete can RTP should become a shared decision-making process including all parties of interest, and ultimately, these decisions will be individualized to each athlete, depending on their circumstances.
Sports medicine physicians are performing meniscal repairs more frequently as the indications for this intervention have expanded over time and may be preferred in athletes because it restores the native anatomy of knee. In comparison, meniscectomy raises concerns for associated increased contact forces about the tibiofemoral joint, with potentially increased pain, worse patient outcome measures, and more rapid degeneration of the knee joint when compared with meniscal repair. Meniscal repair, however, requires more extensive rehabilitation and results in a longer time out of play.
Meniscal repair rehabilitation
Rehabilitation protocols following meniscal repair vary widely. The significant variability in rehabilitation protocols may stem from the multitude of factors contributing to meniscal healing. When developing a rehabilitation plan, tear location (peripheral vs central) and pattern (longitudinal, radial, complex) should be considered. In addition, many other factors (tear chronicity, concomitant injuries, alignment, tissue quality, surgical technique) may impact physical therapy protocols and clinical outcomes, further contributing to the heterogeneity in protocols across the literature. An individualized approach to the patient’s recovery, while following general rehabilitation guidelines, should be established between the surgeon and physical therapist.
Following meniscal repair, 2 general approaches to postoperative rehabilitation exist: protective versus accelerated. The more traditional protective protocols recommend non-weight-bearing while limiting knee flexion to 90° for the first 6 weeks postoperatively, with deep knee flexion avoided for 4 to 6 months. Early protocols recommended immobilization in full extension for 6 weeks.
Over time, more aggressive accelerated rehabilitation protocols allowing earlier weight-bearing and unrestricted range of motion (ROM) have been developed, challenging the dogma of the traditional protective approach. Multiple biomechanical studies have lent support to the tenets of an accelerated rehabilitation approach. A cadaveric study by Ganley and colleagues demonstrated that loading of a posteromedial meniscal tear did not significantly distort the repair, whereas a cadaveric study by Lin and colleagues found that compression rather than repair gapping occurs in longitudinal posteromedial tears during knee flexion. A more recent study by McCulloch and colleagues also found compressive forces across longitudinal medial meniscal tears during simulated gait. Barber has shown this to be safe and effective with no difference in healing rates or patient outcomes in patients undergoing accelerated rehabilitation. Furthermore, Shelbourne and colleagues demonstrated that athletes undergoing accelerated rehabilitation were able to RTP twice as fast as athletes undergoing the standardized protocol (10 weeks vs 20 weeks), without any differences in failure rates or functional performance on RTP. In addition, a metaanalysis by O’Donnell and colleagues demonstrated that early ROM and immediate postoperative weight-bearing have no detrimental effects on clinical success after isolated meniscus repair.
All varieties of meniscal tears may not be amenable to an accelerated rehabilitation protocol. Radial tears present 1 example, because axial loading through complete radial tears leads to circumferential hoop stresses, which create distraction at the tear site. Weight-bearing in 90° of knee flexion results in a 4-fold increase in posterior horn meniscal pressures compared with weight-bearing in full extension, lending evidence to the practice of avoiding deep knee flexion after complex pattern repairs.
The phases of physical therapy following meniscal repair can generally be divided into protective, restorative, and return to activity/sports preparation phases. Although 1 suggested timeline is outlined in this article, the timing should be tailored to each patient based on their progression through rehabilitation.
A typical protective phase spans the first 6 postoperative weeks and is usually the most time-driven phase of rehabilitation to allow an adequate period of meniscal healing. The early protective phase (0–3 weeks) includes a focus on pain/edema control, early patellar mobilization, maintenance of terminal knee extension, and quadriceps neuromuscular training. Peripheral longitudinal tears may be advanced from toe-touch weight-bearing in extension to full weight-bearing in extension over the first 6 weeks, whereas more complex or radial repairs may be held at partial weight-bearing longer. For simple peripheral repairs, ROM may progress rapidly through goals of 0° to 90° by the end of week 1 to 0° to 135° by week 4. ROMprogression is slower for complex posterior tears, limiting flexion to 70° up to week 3, 90° at week 4, and 120° at week 5. Hamstring strengthening should be avoided because of the posterior attachments of the semimembranosus and popliteus to the medial and lateral menisci, respectively. A normalized gait pattern free of bracing is the goal at 6 weeks.
Criteria for progression to the restorative phase of rehabilitation include full passive ROM, no effusion, and neuromuscular control of the quadriceps. The typical timeframe of this phase includes weeks 6 to 12 postoperatively. The focus of the restoration phase is closed kinetic chain strengthening, including squatting above 90° flexion, lunges, and step-ups. Hamstring strengthening can be initiated in this phase. Another key component of the restoration phase is proprioceptive and single leg balance training.
At approximately 12 to 16 weeks, a return to activity phase of rehabilitation begins once the patient demonstrates full active ROM and adequate single leg dynamic knee control. The focus during return to activity is increasing neuromuscular control and building strength, with isokinetic exercises permitted. A graduated return to jogging is typically permitted for peripheral tears during this phase once the patient has appropriate strength, has good frontal and sagittal plane control, and performs low-level agility exercises without pain. In complex repairs, surgeons may choose to refrain from a return to jogging program for 16 to 24 weeks at their discretion.
Kozlowski and colleagues described a return to sport rehabilitation program following the basic therapy principles of progression from low to high loads, slow to fast motions, stable to unstable platforms, uniplanar to multiplanar motions, and concentrating to distracted performances. The investigators provided a set of baseline criteria for initiation of the return to sport phase, which included absence of effusion, full active ROM, 70% operative leg strength versus contralateral, and Lysholm and SANE subjective scores greater than 75 points.
Return to play
It is important that the athlete be appropriately counseled preoperatively regarding the extensive rehabilitation period to manage the athlete’s expectations regarding time to RTP. Although no evidence-based definitive RTP criteria have been established, certain principles can be followed ( Box 1 ). Allowing the athlete to RTP should be an informed, shared decision between the physician, the athlete, and the athletic trainer or physical therapist supervising the athlete’s rehabilitation. The athlete should be assessed for full, symmetric, pain-free ROM at the knee, with no obvious strength discrepancies, including ability to perform single leg squat. The athlete’s psychological readiness to RTP should also be considered. Coordination with the athletic trainer or physical therapist supervising the athlete’s rehabilitation protocol helps ensure the athlete is able to perform sport-specific activities without apprehension. Finally, the athlete must demonstrate normal running mechanics and sufficient neuromuscular control when performing dynamic sport-specific activities before returning to play. The authors do not currently recommend using repeat imaging or second-look arthroscopy to evaluate healing to determine if a player is ready to RTP. Studies have demonstrated that the use of MRI is limited, because it is difficult to determine the degree of healing, and incomplete healing may not be correlated with a decrease in function or an increased risk of retear. Willinger and colleagues demonstrated reassuring RTP rates in 30 athletes despite incomplete healing in 56% of menisci 6 months after meniscal repair. Despite incomplete healing, 100% of the athletes were able to RTP without functional impairments. Although second-look arthroscopy may be indicated if one is concerned with reinjury or persistent pain, it is not recommended in an asymptomatic athlete because of the potential risks and costs.
Full, painless knee ROM that is symmetric to the uninjured limb
No reactive effusions with sport-specific activities
Return of normalized running mechanics
Appropriate neuromuscular coordination demonstrated by the ability to perform regular and single leg jumps, agility ladder drills, lateral hops, and change in direction/cutting drills
Greater than 90% of strength regained for knee extension, flexion, and single-leg press
Psychologically ready for return demonstrated by lack of apprehension with sport-specific activities
Several factors may influence healing and increase the risk of reinjury following meniscal repair. These factors include tear type, rim width/zone of tear, medial versus lateral meniscus tear, and the presence of concomitant injuries. Although there is a paucity of data showing how these tear characteristics affect RTP and performance, it is important to consider them when discussing RTP with athletes and managing their expectations regarding risk of failure and the possible need for further procedures down the road. In a study of isolated arthroscopic meniscal repair in patients less than 18 years old, Krych and colleagues observed significant differences in rim width and tear complexity among successfully repaired menisci and failed repairs, with tears having rim widths greater than 3 mm being significantly more likely to fail. Complex tears and bucket-handle tears were more likely to fail compared with simple tears, with each accounting for 41% of all failures. Regarding isolated medial versus lateral meniscus repair, the data regarding the relative risk of failure are conflicting. Lyman and colleagues retrospectively reviewed 9529 patients who had a meniscal repair over a 7-year study period and demonstrated a decreased risk of failure requiring subsequent meniscectomy for lateral meniscal repair compared with medial. Conversely, Tuckman and colleagues demonstrated repairs of the medial meniscus to have a 20.3% failure rate compared with 44.8% in the lateral meniscus. Such conflicting data likely suggest that no significant difference exist; however, further research elucidating any difference is needed.
Concomitant meniscal injuries in the presence of acute anterior cruciate ligament (ACL) rupture is extremely common with studies demonstrating up to 80% ACL ruptures to have associated meniscal tears. The current standard of care in the active population is to repair these injuries simultaneously. Biomechanical data have demonstrated the forces about the meniscus to increase up to 200% in the ACL deficient knee, suggesting an increased rate of failure following meniscal repair in an ACL deficient knee. Studies to date have supported this finding, demonstrating decreased rates of failure following meniscal repair if performed simultaneously with ACL reconstruction (ACLR). In a matched-cohort population study, Wasserstein and colleagues compared the need for reoperation in a total of 1332 patients with isolated meniscal tears undergoing meniscal repair only versus those with concomitant ACL injuries undergoing simultaneous meniscal repair and ACL. The investigators demonstrated a 42% relative risk reduction of reoperation in those undergoing simultaneous ACLR and meniscal repair versus patients undergoing meniscal repair alone. There have been multiple hypotheses for these observed differences, including possible biological augmentation secondary to bone marrow stimulation at the time of bony tunnel drilling, similar to microfracture techniques. In athletes with these concomitant injuries, it is important to counsel the athlete to expect longer times to RTP than those with isolated meniscus injury, and this delayed return may contribute to improved meniscal healing rates. A recent systematic review showed a mean RTP at 5.6 months for isolated meniscal repair versus 11.8 months in athletes requiring concurrent ACLR.
Meniscal repair outcomes
Meniscal repair can be performed in an attempt to preserve meniscal tissue in situations whereby there is viable tissue with satisfactory healing potential, because partial or total meniscectomy has been shown to increase knee cartilage degeneration in younger athletes. Multiple repair techniques exist, including the inside-out, all-inside, and open repair, with the inside out technique remaining the gold standard for repair. Logan and colleagues evaluated 42 elite athletes who underwent meniscal repairs using an inside-out technique and reported that 81% of patients returned to their main sport at a similar level at a mean time of 10.4 months. This timing reflects the fact that there was a high level of concomitant ACLR within this study population. This study also demonstrated an overall failure rate of 24%, with the vast majority being from medial meniscus repair. Alvarez-Diaz and colleagues evaluated 29 elite athletes who underwent meniscal repair (14 meniscal repair alone, 15 with associated ACLR) using an all-inside technique, reporting that 89.6% returned to the same level of sport, and those who underwent a meniscal repair alone returned at a mean time of 4.3 months, with a 6.7% failure rate. Tucciarone and colleagues evaluated 20 patients with isolated meniscal tears who underwent an all-inside repair, reporting 90% return to sport at 2-year follow-up. Meniscal repair can provide excellent results for athletes with goals of returning to sport; however, the physician must set appropriate expectations with the patient regarding recovery time and postoperative rehabilitation.
Meniscal repair versus partial meniscectomy
In comparison to meniscal repair, isolated meniscectomy has been performed in situations whereby there is nonviable meniscal tissue or nonsatisfactory healing potential. Nawabi and colleagues evaluated 90 elite soccer players who underwent isolated partial lateral or medial meniscectomy and reported that 100% of patients returned to previous level of sport at an average of 5 to 7 weeks, but noted that the time for return to sport was significantly longer in patients undergoing partial lateral meniscectomy when compared with those undergoing medial meniscectomy (7 weeks vs 5 weeks, P <.01). Furthermore, it should be noted that 69% of players who underwent partial lateral meniscectomy experienced adverse events, including persistent effusions and lateral joint line pain, in comparison to only 8% of these events experienced in the medial meniscectomy group. Furthermore, 7% of the partial lateral meniscectomy patients required subsequent arthroscopic surgery, whereas no patients in the partial medial meniscectomy group required further intervention. Kim and colleagues evaluated 56 athletes who underwent partial lateral or medial meniscectomy and reported a significantly faster return to sport in those undergoing partial lateral meniscectomy (61 vs 79 days, P = .017). Osti and colleagues evaluated 41 athletes who underwent isolated partial lateral meniscectomy and reported 98% return to sport at a mean time of 55 days, with elite athletes averaging a shorter return to sport time than recreational athletes. Athletes should be counseled that partial meniscectomy can provide an opportunity for more rapid return to sport than meniscal repair, but there is significant risk of future cartilage degeneration.
Although the results of both partial meniscectomy and meniscal repair are consistently good to excellent, complication rates can vary based on treatment type and level of athlete. Complications include significant knee pain that delays RTP, failure of meniscal repair that requires reoperation, or failure of meniscal repair or partial meniscectomy requiring further meniscal excision. In a systematic review, Eberbach and colleagues evaluated sport-specific outcomes after meniscal repair in patients ranging from recreational athletes to professional athletes. In their review of 27 studies and 637 patients, the pooled failure rate was 21%; however, there was a significantly lower failure rate among professional athletes when compared with mixed-level athletes (9% vs 22%, respectively). Although partial meniscectomy generally produces good to excellent results with low complication rates, several studies have reported persistent knee pain requiring athletes to decrease their activity level. Furthermore, rapid chondrolysis has been reported after partial lateral meniscectomy in active patients, a rare but serious complication that can severely debilitate athletes with goals of returning to sport. Although rare, physicians must counsel their patients about the possible complications of sustained debilitating knee pain and the potential necessity of reoperation, regardless of surgical treatment.
Meniscal injuries in young and athletically active patients present a challenge in terms of treatment, rehabilitation, and return to sports. The surgeon must balance the importance of preserving meniscal tissue with the patient’s needs for rapid return to sport. Paxton and colleagues highlighted the importance of meniscal preservation in a systematic review that compared meniscal repair and partial meniscectomy in both short- and long-term outcomes. This study evaluated more than 1000 patients and found that although partial meniscectomy had a lower reoperation rate at short-term follow-up, patients undergoing meniscal repair recorded significantly high functional scores at long-term follow-up. These results were supported by additional systematic reviews. Despite excellent long-term results, meniscal repair typically requires a longer rehabilitation period and is a more technically challenging procedure than partial meniscectomy; therefore, partial meniscectomy is frequently preferred by patients and surgeons to allow earlier return to sports. Furthermore, partial meniscectomy has generally demonstrated excellent short-term results with low complications rates, making this procedure attractive to athletes with short-term career goals (professional athlete at end of career). Physicians must counsel their athletic patients on the role of the menisci in preservation of knee joint biomechanics, because several studies have shown that removal of meniscal tissue in patients with high functional demands can accelerate degeneration of the articular cartilage and decrease both athletic performance level and career lengths. Therefore, it is paramount that physicians counsel patients to achieve an understanding of individual athletic goals when counseling on appropriate treatment of meniscal injury.
Return to play and performance following meniscal repair
RTP rates following meniscal repairs in athletes are reassuring with 80% to 95% of athletes returning to play ( Table 1 ). Furthermore, studies to date have demonstrated that athletes undergoing isolated meniscal repairs can expect to RTP around 4 to 6 months. Understandably, athletes with concomitant ACLR should expect longer RTP times, with most studies demonstrating athletes returning to play at 8 to 12 months because the timing is limited by the ACLR. Specific data regarding performance upon RTP are sparse. A recent metaanalysis focusing on sport-specific outcomes following meniscal repair demonstrated improved functional outcome scores with the Tegner activity ratings increasing from a means score of 3.5 preoperatively to 6.2 ( P <.01) postoperatively in 664 patients pooled from 28 studies. Unfortunately, data looking at differences in RTP rates and performance outcomes for specific sports are currently lacking. It is likely that RTP rates and performance vary significantly between sports because of the differences in demands and sport-specific activity requirements. The authors encourage further research to further investigate these differences.