Treatment, Return to Play, and Performance Following Meniscus Surgery

Abstract

Purpose of Review

The standard of care in meniscal tear management is constantly evolving, especially for athletes and high-demand patients. Meniscus repairs, meniscus transplants, and partial meniscectomies are commonly performed, and rehabilitation methods following these operations are becoming more sophisticated. The ultimate goal of these procedures is returning patients to full activity with minimal risks. Return to play should be systematic, pathology dependent, and individualized to an athlete’s needs, expectations, and level of play. This article provides a review of the current treatment modalities of meniscus tears, the rehabilitation protocols following each modality, and the return to play criteria that must be met before releasing the player to competition. In addition, it overviews articles that describe performance outcomes of patients that have undergone meniscus surgery.

Recent Findings

Current research shows high return to play rates for athletes that undergo meniscus surgery and describes effective rehabilitation protocols to facilitate recovery. There is an increased emphasis on meniscus preservation in recent literature. In addition, meniscus allograft transplantation has demonstrated its efficacy as a salvage procedure and has become a stronger consideration in the athlete with meniscus pathology.

Summary

No standardized return to play protocol can be applied uniformly to all kinds of meniscal surgeries, and two athletes with the same pathology cannot be expected to follow identical paths towards full recovery. A multidisciplinary approach to care should be provided to the patients, and in the case of patients with high levels of athleticism, the road to recovery starts even before the injury itself.

Introduction

Meniscus surgery is a common arthroscopic procedure performed in the USA and around the world [1–4]. Common surgical approaches to treating meniscus tears include partial meniscectomy, meniscal repair, and meniscus transplant. Meniscus tears are classified by their type and location. The outer, vascularized third of the meniscus is often referred to as the “red zone”; the middle, moderately vascularized third the “red-white” zone; and the inner, avascular third the “white zone.” Though it has been suggested that tears in avascular zones may be amenable to repair in competitive athletes [5], it is widely accepted that the more vascularized the location of a tear the better the healing prognosis of repair is [6]. The risk for sustaining a meniscal tear is especially high in athletes [7]; however, consensus on postoperative outcomes in athletes can be obfuscated by studies performed on a broader population. Postoperative outcomes of particular interest in athletic populations are time to return to play and performance measures. Urgency to return to play, preservation of performance and knee function, as well as functional longevity, are all considerations during the patient-surgeon conversation. Depending on an athlete’s age and level of play, each of these considerations might be weighed differently. The primary objective of this paper is to review current literature regarding meniscal surgeries that describe postoperative treatment, return to play statistics, and performance outcomes. Understanding these parameters can help clinicians make better decisions with their patients in terms of treatment options as well as better inform them on what to expect post-surgery.

Partial Meniscectomy

Partial meniscectomy is indicated in a patient who has failed conservative treatment with a symptomatic torn meniscus that has a low probability of healing if repaired. As a general guideline, radial tears, degenerative tears, complex tears, and tears within the “white zone” fall into this category. There are several factors to consider when performing a meniscectomy. A recent systematic review describes preoperative sport level, sex, and type of meniscal tear having no impact on clinical outcomes of meniscectomy; however, previous osteoarthritis, chronic symptoms, and increased amount of resected tissue are correlated with worse clinical outcomes [8••]. In younger populations, due to high success of healing of meniscal repair regardless of vascular zone, meniscectomy is often not the preferred approach [5, 9]. In older patients with degenerative meniscal lesions, meniscectomy is generally not indicated until they fail conservative treatment [10, 11] or the patient has a symptomatic tear [12].

Rehabilitation

Following meniscectomy, patients can have decreased strength [13], decreased range of motion [14], altered proprioception [15,16], abnormalities in gait [17, 18], and other biomechanical measures that predispose them to osteoarthritis [14, 19•, 20]. Many of these factors can be targeted by a post-meniscectomy rehabilitation program and improve patient outcomes [21–23]. Jahan et al. recently developed an 8-week rehabilitation program specifically tested on athletes between the ages of 18 and 35 that included hydrotherapy and massage therapy. The program led to better outcomes when compared to a conventional rehabilitation protocol [24]. Also, of note is a recent prospective, randomized, placebo-controlled trial that suggests that the use of adductor canal and femoral nerve blocks are equally effective measures for improving postoperative pain scores and rehabilitation potential in patients undergoing meniscectomy compared to controls [25]. Despite these suggestions, there is no standardized rehabilitation protocol following partial meniscectomy. Koch et al. analyzed fifteen postoperative orthopedic surgeon meniscectomy rehabilitation protocols. The study found that no protocols advocated for use of an orthosis or limitations on range of motion and full weight bearing began at an average of 0.6 weeks. Additionally, on average, active range of motion exercises remained part of the protocols for 3.8 weeks; non-specific training activities such as cycling and strength training began at 3.2 weeks, and activities such as sports-specific training began at 7.3 weeks. The study concluded that, in general, postoperative rehabilitation protocols are appropriate and follow up-to-date rehabilitation guidelines [26].

At our institution where NCAA Division 1 athletes regularly receive care, post-meniscectomy protocols range from 8 to 12 weeks, and incorporate a variety of modalities including electrotherapy, cryotherapy, and progressive resistance exercises. For an athlete, the authors recommend an 8-week rehabilitation program (Table 1). During the first week postoperatively, patients wean off crutches as tolerated while performing a series of effusion-control and range of motion exercises. In the second week, athletes perform gait training, balance, stationary bicycle, and strengthening exercises. In weeks 2 to 4, athletes undergo gait normalization and progress through more advanced strengthening and range of motion exercises. In weeks 4 to 6, along with progressive strength, balance, and range of motion exercises, the athlete will begin running and cutting drills. If patients have full and painless range of motion, after week 6 they perform sports-specific exercises and gradually return to sport. The protocol is accelerated, decelerated, and modified as needed for individual athletes, particularly for those that are in season.

Table 1.

Example meniscectomy rehabilitation protocol

Time	Exercises/Therapy	Goals	Progression Criteria
1–3 days*	-Weight bearing as tolerated with bilateral crutches during ambulation -Single leg raises -Heel slides -Seated ankle pumps -Patellar tendon mobilizations	-Pain reduction -Effusion reduction -Reduce scar tissue adhesion -Improve quadriceps activation	-Full knee extension -Quadriceps isometric contraction -Weight bearing without crutches
4–7 days	-Weight bearing as tolerated, wean use of crutches -Single leg raises -Hip abduction/adduction/extension -Bilateral balancing drills -Hamstring, gastrocnemius, soleus, IT band, quadriceps stretches
1–2 weeks	-Treadmill waking/gait training -Unilateral balance drills -Single leg raises** -Stationary bicycle	-Pain reduction -Effusion reduction -Improve knee range of motion -Improve strength -Normalize gait	-Minimal effusion -Normal gait -Full passive range of motion -Active range of motion 0–90 degrees
2–3 weeks	-1/3 to 1/2 squats -Leg press** -Knee extension (90–40 degrees) -Hamstring curls -Calf raises -Stationary bicycle**
3–4 weeks	-Increase intensity of above exercises -Lateral step up -Lateral and front lunges -Unilateral calf raise -Pool exercises -Elliptical or StairMaster	-Improve strength -Improve balance and proprioception -Increase agility -Normalize plyometric movements	-Full painless active and passive range of motion -Quad strength > 80% of contralateral leg -Painless jogging
4–6 weeks	-1/2 to full speed running -Progress to cutting drills -Increase depth of squats and leg press -Bilateral/Unilateral Plyometric Drills
6–8 weeks	-Sports-specific exercises added -Gradual return to full competition	-Return to sport -Normalize sports-specific movements and mechanics	-Quad strength >85–90% of contralateral leg -FLEE test*** -Athlete readiness

*Neuromuscular electrical stimulation and cryotherapy can be used as necessary

**Weight increased as tolerated

***Functional lower extremity evaluation [27]

Postoperative Outcomes

There is a dearth of recent literature regarding postoperative outcomes of athletes that have undergone meniscectomy. The findings of these recent studies are summarized in Table 2. Ultimately, due to so few recent studies across a limited range of sports, there is little to guide treatment and inform athletes about postoperative outcomes and performance, especially when stratified by sport, type of tear, and level of play. Future studies are warranted to better elucidate sports-specific and demographic-specific outcomes of patients that undergo partial meniscectomy.

Table 2.

Postoperative outcomes of meniscectomy in athletes

Study	Population	Surgery performed	Return to play and/or performance metrics	Other findings
Nawabi et al. (2014)	90 male, high level professional soccer players averaging 22 to 23 years old	Partial medial meniscectomy (42 players) and lateral meniscectomy (48 players)	100% returned to play. Return to play after lateral meniscectomy was 7 weeks, while in medial meniscectomy it was 5 weeks.	69% of the lateral meniscectomy group had adverse events related to pain and swelling compared to 8% in the medial meniscectomy group, and 7% required a revision arthroscopy compared to none in the medial meniscectomy group [28].
Kim et al. (2013)	Male (45) and female (11) athletes. 15 were soccer players, 10 basketball players, 7 baseball players, 5 volleyball players, and 4 rugby players. 12 were considered elite athletes, 23 were considered competitive, and 21 were considered recreational athletes. Average age was 26.7 (range: 13–67).	Partial medial meniscectomy (16 athletes) and partial lateral meniscectomy (40 athletes). The lateral meniscectomy group included 8 discoid menisci.	The average time to return to sport was 54 days in the under 30 patients, while it was 89 days in the over 30 age group. Return to sport was 79 days after medial meniscus surgery, and 61 days after lateral meniscus surgery.	22% of the athletes undergoing medial meniscus surgery and 53% of athletes undergoing lateral meniscus surgery had pain and/or effusion in the knee after returning to sports. Larger resections and high level of activity predicted a faster return to play [29].
Marigi et al. (2021)	Competitive male wrestlers averaging 18 years old. 39 competing at a high school level, 14 at a collegiate level, 1 at a professional level, and 2 at a club sport level. Average preoperative Tegner score: 6.5)	Medial (40 wrestlers) and lateral partial meniscectomy (15 wrestlers) or both (1 wrestler)	Athletes were cleared for return to sport at 6 weeks. 89% returned to sports, while only 65% returned to wrestling. (average postoperative Tegner score: 8.3)	The study also examined a meniscus repair group and found a 21% reoperation rate in meniscal repair compared to 3% for partial meniscectomy. Researchers found no significant difference in return to play and activity scores in athletes who underwent meniscectomy and meniscal repair [30].
Aune et al. (2014)	72 NFL athletes averaging 26.9 years old	77 Partial lateral meniscectomies	61% of the athletes returned to previous level of play after partial lateral meniscectomy at an average time of 8.5 months. Running backs, receivers, linebackers, and defensive backs returned to play at a lower rate than lineman and tight ends. Return to sport was especially low for undrafted players or late-round draft pics.	ACL repair and other concomitant surgical procedures did not significantly affect the likelihood of an athlete return to play [31].
Khalil et al. (2021)	12 athletes competing in the NBA combine averaging 20.6 years old	Partial meniscectomy (unspecified laterality)	Players had no significant differences in performance on the lane agility test, shuttle run, ¾ court sprint, standing vertical jump, or vertical max jump when compared to controls.	Standing vertical jump, max vertical jump, and the agility test improved the more months after surgery an athlete participated in the combine [32].
Chahla et al. (2018)	287 athletes competing in the NFL combine	Partial medial (81) and lateral meniscectomy (206)	Researchers found poorer performance metrics, fewer games started per season, and fewer games played per season in athletes that underwent partial meniscectomy compared to matched controls.	Meniscectomies where 10% of medial or lateral meniscal tissue volume excised was correlated to increased chondral lesion severity and size. Performance measures were significantly worse in players with severe chondral lesions [33••].

Long-term Outcomes

Partial meniscectomy can be a tempting first choice for athletes due to the short recovery time [34]. However, athletes are a high-risk population for osteoarthritis [35, 36], and it has been shown in past literature that the risk of degenerative arthritis increases in comparison with use of other meniscus-sparing procedures. Recent studies have found that patients who undergo partial meniscectomy have an increased risk of getting a knee replacement in comparison to the general population [37], as well as patients treated with non-operative management [38•]. In addition, Smith et al. found that in collegiate American football athletes who had undergone a meniscectomy, the prevalence of osteoarthritis was 27% compared to 11% in those that had undergone meniscal repair [39]. Prien et al. found that previous meniscectomy was a significant predictor of chondral loss in retired female professional soccer players [40•]. It has also been suggested that meniscectomy poses a greater cost than non-operative treatment [38•]. These implications cannot be ignored, and it is the responsibility of the surgeon to properly weight the risks and benefits of meniscectomy against other treatment options with the patient.

To mitigate these undesired outcomes, meniscus scaffold with a collagen or polyurethane implant is an emerging therapy performed after extensive partial meniscectomy [41, 42]. However, return to play statistics and rehabilitation methods after meniscus scaffolds are out of the scope of this review due to a scarcity of independent comparative and outcome studies with adequate long-term follow-up [43].

Meniscus Repair

Every effort should be made to save the meniscus; however, isolated meniscal tears pose a challenging problem in terms of healing and subsequent rehabilitation (91% meniscal healing when associated with ACL reconstruction versus 50% when tears were isolated) [44]. Different types of meniscal tears are repaired using different techniques: Peripheral vertical tears heal well and are best repaired with multiple vertical mattress sutures, which perform better than a horizontal mattress configuration [45]. Horizontal tears, previously thought to have minimal healing capacity, have historically been managed by meniscectomy or leaflet resection. However, increasing awareness of the importance of meniscus preservation has led to these tears being repaired, especially in younger patients. Kurzweil reports a 78.6% healing rate in this tear pattern [46].

Several methods of repair can be used ranging from all-inside repair to transtibial repair [46]. Recent emerging reports have also discussed the impact of root tears on normal meniscal function, since this tear type often leads to meniscal extrusion and secondary degenerative joint disease [47, 48].

Rehabilitation

There are copious rehabilitation protocols following meniscal repairs [26] but no difference in outcome in terms of failure rates, patient-reported symptoms, or return to sport has been demonstrated [49]. In general, the rehabilitation protocol should be tailored to the tear pattern since each pattern behaves differently when subjected to physiological loads [50]. In vertical and bucket handle tears, axial loading exerts hoop stresses that compress the repair and contributes to its healing, while the same loading on a radial tear repair will displace its reduction and subsequently delay healing [49].

Presently, no unanimous recommendations for the ideal postoperative rehabilitation program following meniscus repair can be ascertained. In a systematic review, Harput et al. concluded that time post-surgery was the most critical factor in return to sports participation decision-making than achievement of specific functional task criteria following arthroscopic meniscal repair [49].

Protocols can be generally divided into weight restricted (used mainly in radial tear repairs), motion restricted (used mainly in unstable vertical tears), dual restricted (used mainly in radial, horizontal, and root tears), or accelerated (used mainly in vertical longitudinal tears) [50]. Weight restriction protocols allow for immediate range of motion but limited weight bearing in the early postoperative period. An example of weight restricted protocol as described by Krych et al. [51] is partial weight bearing with crutches for the first 4 weeks, with no squatting or pivoting for 16 weeks and return to sport after 16–24 weeks.

Motion restriction protocols allow weight bearing in a locked hinge brace and weight bearing in full extension with crutches for 4 weeks [52].

Dual restriction protocols are usually reserved for the unstable or low potential of healing tears such as radial and root tears, with immobilization of the knee and non-weight bearing status for a minimum of 2 weeks, followed by slow progression in motion and weight bearing [53]. However, it is well known that any restriction in motion or weight bearing will lead to muscle atrophy and decreased strength which will prolong the return to play [54]. To prevent weakness, accelerated protocols have been introduced and different studies showed no difference in patient outcomes between accelerated and restricted rehabilitation after isolated meniscal repair [50, 53]. It is worth noting that these comparisons studied isolated vertical tears [53,55].

The authors prefer a rehabilitation protocol that is tailored to the tear type, repair technique, and level of activity (Table 3). Presently, we utilize an accelerated protocol for repaired vertical tears. Most tears are treated with an all-inside repair technique. Weight restriction protocols are utilized for radial tears and dual restriction protocols for root and horizontal tears which are treated with transtibial fixation and all-inside suturing respectively (Table 4). Athletes can expect to return to sports around 4 to 6 months after isolated meniscal repairs [56]. However, in order to release the players to full sport, certain criteria have to be met. These include full painless range of motion, normal running mechanics, appropriate proprioception, protective strength, and psychological readiness [57•, 58].

Table 3.

Example of general meniscus repair and meniscus allograft rehabilitation

Time	Exercises/Therapy	Goals	Progression criteria
-Accelerated: 0–2 weeks -WRP: 0–3 weeks -DRP: 0–5 weeks*	-Ankle pumps -Patellar mobilizations -Straight leg raise -Hip adduction -Heel slides (ROM restrictions in Table 4) -TTWB	-Manage pain and effusion -Full passive extension -Improve quadriceps activation	-Knee AROM 0–90 degrees -Adequate patellar mobility -Adequate quadriceps isometric contraction
-Accelerated: 2–3 weeks -WRP: 3–4 weeks -DRP: 5–6 weeks	-1/3 to 1/2 body weight ambulation -Straight leg raise** -Hip adduction and abduction -Ankle pumps -Knee extension and flexion against resistance (90–20 degrees) -¼ squats -Gastrocnemius and soleus stretching -Hamstring and IT band stretching
-Accelerated: 3–4 weeks -WRP: 4–6 weeks -DRP: 6–8 weeks	-¾ to full weight bearing ambulation -Increased resistance knee extension and flexion -Weight shifts -¼ to ½ squats on leg press** -Static balance exercises -Calf raises -Ankle resistance exercise -Stationary cycling	-Increase knee AROM -Improve strength -Normalize gait -Improve balance	-Knee AROM 0–135 -Full patellar mobility -Minimal effusion -Fluid gait
-Accelerated: 4–5 weeks -WRP: 6–8 weeks -DRP: 8–10 weeks	-Treadmill walking -Forward and lateral step up and downs (2–4 inches) -Stair climber machine -Mini-trampoline light bouncing -Balance exercises (i.e., single leg standing) -Water exercises -Knee extension and flexion against resistance**
-Accelerated: 5–6 weeks -WRP: 8–9 weeks -DRP: 11–12 weeks	-Full extension against resistance** -Leg press up to 100 degrees of knee flexion** -Hamstring curls to 90 degrees** -Slide board -Balance exercises -Single leg deadlifts** -Walking with light resistance -Light hopping on mini-trampoline	-Prepare for return to sport -Normalize jogging and plyometric exercises -Full knee AROM -Improve jumping and landing mechanics -Increase strength -Improve agility and functional movement	-Full painless active and passive range of motion -Quad strength > 80% of contralateral leg -Painless jogging
-Accelerated: 6–8 weeks -WRP: 9–12 weeks -DRP: 12–14 weeks	-Transition to jogging -Backwards running -Single leg squats to 90 degrees -Light hopping on level ground -Swimming figure eights -Plyometric exercises -Begin sports-specific strengthening
-Accelerated: 8–12 weeks -WRP: 12–16 weeks -DRP: 14–20 weeks	-Transition to running and sprinting -Jumping and landing exercises -Cutting exercises at 45, 75, and 90 degrees -Noncontact sports-specific exercises	- Return to sport	- FLEE test*** - Quadriceps strength >85–90% of the uninvolved limb - Athlete readiness to return to play
-Accelerated: 12+ weeks -WRP: 20+ weeks -DRP: 20+ weeks	-Gradual return to sports-specific exercises

*Neuromuscular electrical stimulation and cryotherapy can be used as necessary

**Weight increased as tolerated

***Functional lower extremity evaluation [27]

Table 4.

Overview of meniscus repair rehabilitation protocols

Protocol	Tear type	Technique	Weight bearing	ROM	Details	Return to sport
Accelerated	Vertical	All-inside	TTWB until week 2 then WBAT afterwards	0–90 first 2 weeks then FROM	ROM at 1 day and TTWB for the first 2 weeks FROM and WBAT at 2–3 weeks	Jogging 6–8 weeks Sports-specific training 8–12 weeks Return to sport at 12 weeks if all criteria are met
WRP	Radial	All-inside	NWB for the first 2–3 weeks	PROM 0–90 first 2 weeks then FROM	NWB for 2–3 weeks, PROM and AAROM for 6 weeks, full ROM at 6 weeks, FWB at 4 weeks	Sports-specific training at week 20. Return to sport if criteria are met
DRP	Root, horizontal	Transtibial, all-inside	NWB for the first 2–3 weeks	0–30 in brace for the 1st 3 weeks then gentle ROM continue to progress to FROM	0–30 ROM in brace, and NWB for the first 2–3 weeks, 0–60 ROM and TTWB at 3–4 weeks, 0–90 ROM and WBAT at 5–9 weeks	Sports-specific training usually at 20+ weeks Return to sport if criteria are met

WRP weight restriction protocol, DRP dual restriction protocol, ROM range of motion, FROM full range of motion, FWB full weight bearing, TTWB toe-touch weight bearing, WBAT weight bearing as tolerated

In our institution, these criteria can be summarized as follows:

1. FLEE test: which is a series of movements that assess lower extremity function [27]

2. Quadriceps strength >85–90% of the uninvolved limb

3. Athlete readiness to return to play.

No further imaging is needed to decide upon return to sports since many studies have demonstrated the limitation of any further imaging including MRI [56].

Postoperative Outcomes

A recent meta-analysis by Totlis et al. examined patients following meniscus repair and found a 90% return to play rate and high postoperative activity levels [59•]. Unfortunately, it is difficult to generalize results from meta-analyses to specific patients as many of their studies use populations with a big difference in their level and type of sport, age, pre- and post-injury activity levels, and presence of concomitant ACL reconstruction. Notwithstanding, the literature supports high return to play rates following meniscal repair, regardless of operative approach.

Recent studies that describe return to play metrics in athlete populations are summarized in Table 5. However, more studies that stratify by the metrics mentioned above as well as those that measure postoperative performance are warranted.

Table 5.

Postoperative outcomes of meniscal repair

Study	Population	Surgery performed	Return to play and/or performance metrics	Other findings
Nakayama et al. (2017)	46 athletes with a mean age of 22.9 years (range 12 to 50 years). Mean Tegner score was 6.2 preoperatively.	18 knees with medial meniscal tears and 28 knees with lateral meniscal tears repaired predominantly with arthroscopic inside-out repair. Fibrin clot augmentation was utilized for poorly vascularized or degenerative tears (11 in the medial meniscus group and 7 in the lateral meniscus group).	14 (77.8%) in the medial meniscus group returned to play at an average of 5.5 months, and 23 (82.1%) of the lateral meniscus group returned to play at an average of 6.8 months (mean Tegner score 6.4).	2 cases (11.1%) of reinjury were identified in the medial meniscus group (both bucket handle tears) and 2 cases (7.1%) of reinjury were detected in the lateral meniscus group [60].
Marigi et al. (2021)	Competitive male wrestlers averaging 16.7 years old. 22 competing at a high school level, 3 at a collegiate level, 1 at a professional level, and 3 at a club sport level. Average preoperative Tegner score: 6.5)	14 medial menisci, 14 lateral menisci, and 1 knee with both. 3 were repaired with bioabsorbable arrows, 10 with all-inside approach, 10 with inside-out approach, 3 via root repair, and 3 via combination inside-out and all-inside techniques.	Return to sports occurred at 4–6 months. 89% returned to sports, while only 65% returned to wrestling. (average postoperative Tegner score: 8.3)	The study also examined a meniscectomy group, finding a 21% reoperation rate in meniscus repair compared to 3% for partial meniscectomy. Researchers found no significant difference in return to play and activity scores in athletes who underwent meniscectomy and meniscal repair [30].
Tucciarone et al. (2012)	40 professional football (13), soccer (20), and basketball players (7) averaging 20 years old	Group A: 10 medial and 10 lateral menisci in stable (with ACL) knees. Group B: 12 medial and 8 lateral menisci in ACL-deficient knees	The study reports 90% of all athletes returned to sports.	Meniscus repair associated with an ACL reconstruction healed faster and at a higher success rate [61].
Vanderhave et al. (2011)	18 children and young athletes averaging 13.2 years old	12 isolated lateral menisci and 6 medial menisci repaired using an inside-out technique.	Return to previous level of activity averaged 5.56 months. 100% of patients returned to sports (mean postoperative Tegner score: 8)	The study also examined patients undergoing meniscal repair with concomitant ACL reconstruction. This group had significantly longer average return to activity times (8.23 months to 5.56 months) and lower average postoperative Tegner scores (6.8 to 8.0) when compared to patients that underwent isolated meniscal repairs. 40 out of the 45 patients in the study (both isolated meniscus repairs and concomitant ACL tear groups) returned to pre-injury level of activity [62].
Kraus et al. (2012)	12 pediatric patients (6 boys, 6 girls) averaging 15 years old (range 4–17)	9 medial meniscus and 3 lateral meniscus repairs	Average preoperative Tegner score of 7.6 deteriorated to 7 postoperatively. 100% of patients returned to full activity following meniscus repair within 6 months.	Outcomes were similar for lateral and medial meniscus repairs. The zone of meniscal injury and method of repair did not affect outcomes [63].
Alvarez-Diaz et al. (2014)	29 male competitive soccer players with a median age of 27 (ranging from 18 to 37) years. Median pre-injury Tegner activity score: 9 (range: 9–10).	Complete longitudinal tears repaired with the Fast-Fix system with an all-inside approach. 15 patients had a concomitant ACL reconstruction, but no significant differences were found when this group was compared to the isolated meniscus repair group.	26 patients (89.6%) returned to the same competition level after surgery.	At the final follow-up (median: 6 years, range of 5–8 years), only 8 athletes were able to return to pre-injury competition level, and only 13 athletes (45%) played at any level. Reasons for this low level of play were related to patient’s job or personal life, not meniscus pathology [64].
Schmitt et al. (2015)	19 patients averaging 14.8 years old. Pre-injury Tegner activity levels in all but one patient (Tegner activity level of 3) were between 7 and 9.	14 lateral menisci and 5 medial menisci were repaired with the all-inside approach using the Fast-Fix system. 11 cases had a concomitant ACL tear.	Average Tegner activity level decreased from 7.6 pre-injury to 7.3 postoperatively.	There were 2 failures that required meniscectomy [65].

Meniscus Allograft

It is well-established that peak tibiofemoral contact pressures increase significantly after total meniscectomy, and meniscal deficiency will lead to the onset and progression of knee osteoarthritis. Meniscal allograft transplantation comes as an option for patients with pain in a meniscal-deficient knee, as it will work to restore the force distribution across the knee and reduce symptoms [66•, 67].

Indications for meniscal allograft usually include patients younger than 55 years, normal axial alignment of the lower extremities, persistent knee pain that is due to lack of the meniscus, and articular chondral wear of Outerbridge grade 2 or less assessed by previous arthroscopic surgery [68].

A graft that is similar to the native meniscus in geometry and size should be chosen to match the physiological joint pressure distribution. Sizing is most commonly performed using the Pollard method with radiographs, MRI scans, or lately 3D MRI using the contralateral meniscus as a reconstruction template [69•]. Grafts can be fresh frozen allografts, cryopreserved, or fresh grafts, though the latter do not offer the surgeon the ability to plan in advance [66•].

Several techniques exist on how to transplant the meniscus: all suture fixation versus bone fixation. Bone fixation can be done using bone plugs or bone bridges. These techniques can be implemented all-arthroscopically or arthroscopically assisted [70].

Rehabilitation

Ideally, range of motion should be regained as early as possible; however, the meniscal allograft should be protected from shearing and rotational stresses in the early postoperative period. Even in studies where range of motion rehabilitation was initiated immediately, full range of motion was not achieved until 6 to 8 weeks after surgery [71•]. Hence, patients who undergo meniscal allograft transplantation are recommended to follow a dual restriction protocol (Table 3). Toe-touch weight restriction should be maintained in the first 5–6 weeks. Full weight bearing should be achieved between weeks 6 and 8. Motion restriction should also be implemented, with a brace locked in extension for the first 2 weeks followed by progression from 0 to 90 degrees during weeks 3 through 8. Exercises can be increased after discontinuation of bracing at 8 weeks. Usually return to sports-specific drills is allowed only at 20+ weeks [72•].

Return to Play

Grassi et al. in a recent systematic review reported that 264 of 379 patients returned to the same sport or physical activity level after meniscal transplant, with soccer, swimming, and running being most common [73•]. In another systematic review, Cvetanovich et al. found that about 75% of athletes could return to sport after meniscal allograft at an average of 12 months postoperatively, with the highest rates of return noted in lower impact sports such as yoga, swimming, cycling, and weightlifting. Only 48.4% of patients returned to their prior level of sporting activities [72•].

Time is the most important determining factor in returning athletes to play and it varies between 3 months for low-impact sports and 6 months for high-impact sports with a mean time of 9 months [71•]. Criteria for return to play should include full restoration of range of motion, return of strength, graft incorporation, no graft extrusion, and the ability to perform sports-specific movements. [70, 71•, 73•].

Table 6 outlines several recent studies with athletic populations that underwent meniscus allograft transplant. In general, it takes longer for patients to return to play following meniscus transplant than repair or meniscectomy. However, it has been demonstrated that many patients are able to return to sport. Future studies are warranted to analyze athlete performance following meniscus transplant.

Table 6.

Postoperative outcomes of meniscus allograft

Study	Population	Surgery performed	Return to play and/or performance metrics	Other findings
Chalmers et al. (2013)	Male (4) and female (9) collegiate track and/or field (2), collegiate basketball (5), collegiate soccer (1), professional baseball (1), collegiate softball (1), high school wrestling (1), high school football (1), and high school soccer (1) athletes (average age: 19.8 years; average pre-injury Tegner score: 8)	11 bridge in slot technique (10 patients) and 3 double bone plug technique. Concomitant procedures included ACL reconstruction, distal femoral osteotomy, osteochondral graft, and microfracture (no significant differences in metrics were found with concomitant procedures).	77% of athletes returned to sport at previous levels of activity, while only 70% returned to their desired level of play. Return to full sport training occurred by 4 months after the operation, while return to previous athletic level on average was 16.5 months (standard deviation: 6.5 months). Postoperative mean Tegner score improved to 9.	23% of patients required revision surgery, and 30% of patients underwent subsequent surgeries [74].
Marcacci et al. (2013)	12 male professional soccer players (average age: 24.5 years, median Tegner score 8)	6 medial and 6 lateral meniscus allograft transplants using an arthroscopic bone plug–free technique with a single tibial tunnel as well as all-inside sutures. Concomitant procedures included ACL reconstruction (2), microfracture (3), osteochondral scaffolding (1), and chondrocyte harvesting (1).	11 patients returned to playing soccer (9 patients, professional soccer; and 2 patients, semiprofessional soccer). Average rehabilitation time: 6.9 months (standard deviation: 1.8 months), average time to return to an official competition: 10.3 months (standard deviation: 2.7 months). Median Tegner scores improved to 10.	One patient developed a knee infection and was not able to return to soccer. In addition, 3 patients underwent an arthroscopic procedures during the follow-up period [75].
Zaffagnini et al. (2016)	74 male and 15 female physically active patients, average age 38.5 (standard deviation 11.2) with an average pre-injury Tegner score of 6.	45 medial and 44 lateral menisci underwent meniscal allograft without bone plug using single or double tunnel technique, fixed with all-inside sutures. 41 patients underwent concomitant procedures, including high tibial osteotomy, ACL reconstruction, distal femoral osteotomy, osteochondral scaffold, mosaicplasty, and microfracture.	74% of patients resumed sports at an average of 8.6 months (standard deviation: 4.1 months), while only 49% returned to pre-injury activity levels. Median postoperative Tegner score was 4.	12% of patients underwent another surgical procedure during the follow-up period (average: 4.2 years) but all returned to sport after the procedure [76].
Stone et al. (2015)	36 male and 13 female patients with a pre-injury Tegner score 8 or above with Outerbridge grade III or IV chondral damage and desire to participate in sports postoperatively. Average age: 45.3 years.	37 medial and 12 lateral meniscal allograft transplants performed using three tunnel technique. Concomitant ACL reconstruction was performed in 4 patients.	73.5% of patients were able to play sports after the operation.	22.4% of transplants failed (average: 5.2 years, standard deviation: 4.4 years). The Kaplan-Meier average estimated survival of the graft was 12.6 years [77].

Pre-injury Evaluation

At our institution, getting elite athletes back to competition is an effort that begins before the injury. Athletes perform an initial screening to assess baseline functional status. The screening includes a squat jump (SJ) test and countermovement jump (CMJ) test performed on a force plate. From force plate data, strength asymmetries are noted, and a metric called the eccentric-utilization ratio which is the ratio of CMJ to SJ is calculated. The eccentric-utilization ratio is a performance measure that can be applied in training [78] and has had utility at our institution for post-injury assessment and return to play. Catapult® wearable technology, a device that uses radiofrequency to measure parameters such as distance traveled, speed, and acceleration during training, is also utilized by our institution to help manage workload and quantify training program intensity (Figure 1).

Fig. 1.

Catapult® technology worn by a soccer player. Image courtesy of Catapult®

Ultimately, performance and workload data help monitor athlete development and loading to avoid preventable injury. Furthermore, it allows individualization of the rehabilitation process to each athlete based on his/her own pre-injury parameters and post-injury performance. This facilitates decision-making in the rehabilitation process and promotes a smoother return to play. In addition to all this, our institution also implements a multidisciplinary team composed of physicians, nutritionists, sports psychologists, athletic trainers, and performance coaches who regularly meet to discuss a strategic approach to each athlete’s recovery and ensure that all the athlete’s needs are met.

Conclusion

The decision tree for meniscus tear treatment is becoming increasingly complex due to athlete demands and their expectations to return to play as quickly as possible. This review provides guidelines for rehabilitation of meniscal injuries in athletes as well as information to guide their postoperative outcomes and performance expectations. Unfortunately, no consensus exists regarding rehabilitation guidelines, and studies of postoperative performance metrics are sparse.

Fortunately, surgeons, sports medicine specialists, physical therapists, and athletic trainers are meeting these challenges with better understanding of these pathologies and with optimal techniques to regain knee function. A multidisciplinary team approach to the athlete should be undertaken in treating meniscal pathologies. The most important member of this team is the athlete himself; his/her expectations, abilities, and morale are important determining factors of his/her rehabilitation and the timing to return to play. Secondary considerations include factors related to the pathology itself, such as the type of the tear and its subsequent management.

The simple yet challenging conclusion is that there is no standardized way to deal with meniscal tears. There is no rule to determine the expected or perfect timing to return to sport, and it is difficult to say how the athlete will perform after surgery. That said, every effort should be made to repair the meniscus, and management of the athlete postoperatively should be as accurate and meticulous as the intraoperative care.

Declarations

Conflict of Interest

Tammam Hanna, Nathan Smith, and Wayne Sebastianelli declare that they have no conflict of interest.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.