Two well-established first-line surgical treatment options exist for symptomatic meniscus tears: surgical repair and partial menisectomy. Generally considered a salvage procedure, meniscus allograft transplantation is a surgical treatment option for patients who have experienced the failure of multiple previous surgeries with symptomatic meniscal insufficiency and post-menisectomy syndrome. If primary surgical techniques fail, meniscal allograft transplantation can be performed with the goal of restoring normal knee kinematics and function while minimizing swelling and pain for patients younger than 55 years with isolated tibiofemoral pain secondary to meniscus tear or previous menisectomy, recurrent joint effusions, and minimal osteoarthritis (greater than 2 mm of tibiofemoral joint space).1 By creating a functional meniscus, athletes may be less likely to suffer from meniscus deficiency symptoms such as instability, swelling, and activity-limiting pain.2
Positive outcomes that include improvements in self-reported function and quality of life have been shown in a nonathletic meniscus-deficient population.3–10 The overall clinical efficacy of the meniscal allograft transplantation has been previously evaluated in a systematic review by Samitier et al.11,12 that primarily focused on surgical technique and graft selection with a cursory evaluation of return-to-sports activity. Patient-reported outcomes are often used as a subjective global measure of pain and function. For the knee specifically, the International Knee Documentation Committee and Knee Injury and Osteoarthritis Outcome Score are common self-report measures.
Despite positive results in a general orthopedic patient population, a systematic analysis of outcomes in a highly dynamic athletic population with regard to their ability to return to sports has not been conducted. Therefore, the purpose of the current review was to examine return-to-play rates in only those athletes involved with highly dynamic cutting sports. Examples include, but are not limited to, soccer, football, lacrosse, and basketball. We hypothesized that approximately 50% of athletes undergoing meniscal allograft transplantation would return to competitive sports 12 to 18 months following surgery. This hypothesis was based on the work of Zaffagnini et al.,13 who found a return-to-activity rate following meniscal allograft transplantation of 74% in a large sample (N = 89) of active patients with ages ranging from 16 to 68 years. In a group of patients with higher physical demands, we expected the return-to-play rate to be lower.
A comprehensive literature search was completed both electronically and by hand. Search terms are listed in Table 1. MEDLINE, SPORTDiscus, and CINAHL databases were used to identify studies meeting the preestablished criteria. The search strategy is illustrated in Figure 1. Inclusion and exclusion criteria were established prior to the literature search. Inclusion criteria were return-to-play outcomes as a specific bivariate outcome, clear definitions of the athletic population, use of the English language, inclusion of humans only, report of the length of time to successful return to play, and mean participant age younger than 40 years. Studies reporting a mean age older than 40 years were excluded with the hope of identifying a homogenous athletic population.
Search Terms and Results for Each Database
Flow diagram of the literature search.
The dichotomous variable (return to play [yes/no]) and continuous variable (length of time from surgery to return to play [months]) were the primary outcomes in this analysis. The return-to-play rate was analyzed as the total percentage of athletes across all studies who returned to play. Concomitant injuries and postoperative Lysholm and International Knee Documentation Committee patient-reported outcomes were also examined to provide a more complete summary of the clinical success of this procedure. Publication bias was a consideration in this systematic review of the literature. Attempts to limit publication bias were noted.
Four studies met the inclusion criteria, resulting in a total of 42 athletes (mean age: 23.2 ± 3.9 years) with a cumulative mean follow-up period of 36.9 ± 11.4 months.14–17 Most athletes were male (31 of 42 patients, 73.8%) and the most common sport was soccer (28 of 42 sports reported, 66.7%). Further demographic information can be found in Table 2. Of the 42 athletes, 35 (83.3%) returned to play at an average of 11.2 ± 5.9 (6.7 to 24) months after surgery (Table 2).
Study Design and Results of Included Studies
Lysholm and International Knee Documentation Committee subjective scores were the most commonly reported preoperative and postoperative patient-reported outcomes. Both Lysholm and International Knee Documentation Committee mean subjective scores significantly improved preoperatively to postoperatively (P < .05) in all studies (Table 3). Cumulative effect sizes for Lysholm and International Knee Documentation Committee subjective scores could not be calculated because standard deviations were not provided by all four included studies.
Preoperative and Postoperative Lysholm and IKDC Subjective Scores
Concomitant chondral lesions were common, with 10 patients (26%) having grade I or II cartilage lesions and 16 patients (41%) having grade III or IV lesions. Treatment of cartilage lesions was addressed in three of the four articles. In Marcacci et al.'s14 study, 4 of the 9 athletes with chondral damage had concomitant procedures to address their lesions (3 microfractures and 1 osteochondral scaffolding). Likewise, in Chalmers et al.'s15 study, 4 of the 9 patients with chondral damage underwent procedures concomitant with meniscal allograft transplantation (2 osteochondral grafts, 1 osteochondral graft with a distal femoral osteotomy, and 1 microfracture). In Kocher et al.'s17 study, 1 patient had a chondroplasty procedure. Additionally, 6 patients (14.3%) had an anterior cruciate ligament reconstruction. In total, 33 of the 42 athletes (78.6%) suffered a concomitant injury.
No publication biases were noted in the included articles. Attempts to minimize bias were found in two of the four articles. Alentorn-Geli et al.16 used an external independent investigator to administer all phone interviews and Marcacci et al.14 had two independent orthopedic surgeons who were blinded to the athletes' histories perform the 12- and 36-month evaluations. Additional attempts to minimize bias were not described. Article quality was assessed using the National Institutes of Health's Quality Assessment Tool for Case Series Studies. Scores for each article can be seen in Table 4. All four studies scored a quality rating of “good” using this assessment tool.
Article Quality Assessed Via the National Institutes of Health's Quality Assessment Tool for Case Series Studies
The purpose of this systematic review was to evaluate return-to-play outcomes following meniscal allograft transplantation in athletes participating in dynamic cutting sports. We hypothesized that approximately 50% of athletes undergoing meniscal allograft transplantation would return to competitive sports 12 to 18 months following surgery. Our hypothesis was supported by the results, although the return-to-play rate was much higher than we had originally anticipated. Despite having a high prevalence of concomitant chondral lesions (66.7%), most athletes in this analysis (83.3%) returned to play in a mean time of 11.2 ± 5.9 months. More impressively, 33 of the 42 patients (78.6%) suffered at least one concomitant injury, suggesting that competitive athletes with concomitant injuries, including chondral lesions, can successfully return to sport.
We hypothesized that approximately 50% of athletes would return to play following meniscus allograft transplantation and the actual rate of 83.3% was higher than expected. One potential rationale for the high return-to-play rate may be that competitive athletes are driven to return to sport due to their competitive nature and/or the financial motivation for those playing professionally. However, Zaffagnini et al.13 demonstrated similar results in a non-competitive, physically active population. In their study, most physically active patients (66 of 89 patients, 74%) with a mean age of 38.5 years (range: 16.7 to 68.8 years) returned to activity following meniscal allograft transplantation. Another rationale for the high return-to-play rate is the ability of this procedure to restore the function of the meniscus as a crucial structure in knee kinematics. The meniscus is a multi-functional structure within the knee that acts to increase stability, shock absorption, lubrication, and transmission of joint forces.18 Meniscal allograft transplantation restores the integrity of the meniscus, thereby improving stability, pain, and function.19 However, although joint stability may be improved by restoring the function of the meniscus, it remains unclear whether meniscal allograft transplantation has the ability to prevent or delay the onset of posttraumatic osteoarthritis.
This systematic review is not without limitations, most notable of which is the low level of evidence in the available literature. This is potentially due to the limited use of this procedure, especially in an athletic population. Meniscal allograft transplantation is a salvage procedure and as such not many centers have a large volume of patients who have undergone this procedure to report on. Within the individual studies, there were additional limitations. Examples include small sample sizes and relatively short-term follow-up periods. Of the athletes included in this review, 73.8% were male and most were soccer players. This may affect the generalizability of the results to females and other sports. Additionally, Marcacci et al.14 focused solely on a population of professional soccer players. Motivation to return to sport in this group is likely multifactorial and includes the loss of personal identity and income. Therefore, these athletes may have had an increased motivation when compared to other, lower-level athletes. The final noteworthy limitation is the variety of “return to play” definitions. It was often unclear whether the athletes were returning to true competition, practice, or functional activity. The quantity and quality of the available literature indicates that additional well-designed multicenter studies are necessary to confirm the accuracy of the currently available results.
To address these limitations, future research should define return to play as a return to competition and the level of that competition should be clearly described. As previously mentioned, published studies focus primarily on male athletes and it remains to be seen whether the same results can be expected in female athletes. Researchers should focus on recruiting female participants to address this disparity. Further, longitudinal studies are warranted to examine meniscal allograft transplantation as a treatment option for competitive athletes.
Meniscal allograft transplantation appears to be an acceptable treatment for meniscal deficiency in athletes, with most patients returning to high-level sport despite a high incidence of concomitant chondral injuries. Furthermore, return to high level sport occurred less than 1 year following meniscal allograft transplantation. These findings must be interpreted cautiously due to the low-level evidence that currently exists in the meniscal transplant literature. Despite the limitations of the current literature, these results are significant for orthopedic surgeons, athletic trainers, and physical therapists because this information is relevant to setting realistic postoperative expectations for athletes requiring meniscal allograft transplantation. Based on the available literature, 83.3% of athletes return to play following meniscal allograft transplantation approximately 1 year after surgery.
- Noyes FR, Heckmann TP, Barber-Westin SD. Meniscus repair and transplantation: a comprehensive update. J Orthop Sports Phys Ther. 2012;42:274–290. doi:10.2519/jospt.2012.3588 [CrossRef]
- Smith NA, MacKay N, Costa M, Spalding T. Meniscal allograft transplantation in a symptomatic meniscal deficient knee: a systematic review. Knee Surg Sports Traumatol Arthrosc. 2015;23:270–279. doi:10.1007/s00167-014-3310-0 [CrossRef]
- Heckmann TP, Barber-Westin SD, Noyes FR. Meniscal repair and transplantation: indications, techniques, rehabilitation, and clinical outcome. J Orthop Sports Phys Ther. 2006;36:795–814. doi:10.2519/jospt.2006.2177 [CrossRef]
- Rue JP, Yanke AB, Busam ML, McNickle AG, Cole BJ. Prospective evaluation of concurrent meniscus transplantation and articular cartilage repair: minimum 2-year follow-up. Am J Sports Med. 2008;36:1770–1778. doi:10.1177/0363546508317122 [CrossRef]
- Ha JK, Jang HW, Jung JE, Cho SI, Kim JG. Clinical and radiologic outcomes after meniscus allograft transplantation at 1-year and 4-year follow-up. Arthroscopy. 2014;30:1424–1429. doi:10.1016/j.arthro.2014.05.032 [CrossRef]
- González-Lucena G, Gelber PE, Pelfort X, Tey M, Monllau JC. Meniscal allograft transplantation without bone blocks: a 5-to 8-year follow-up of 33 patients. Arthroscopy. 2010;26:1633–1640. doi:10.1016/j.arthro.2010.05.005 [CrossRef]
- Saltzman BM, Bajaj S, Salata M, et al. Prospective long-term evaluation of meniscal allograft transplantation procedure: a minimum of 7-year follow-up. J Knee Surg. 2012;25:165–175. doi:10.1055/s-0032-1313738 [CrossRef]
- Verdonk PC, Verstraete KL, Almqvist KF, et al. Meniscal allograft transplantation: long-term clinical results with radiological and magnetic resonance imaging correlations. Knee Surg Sports Traumatol Arthrosc. 2006;14:694–706. doi:10.1007/s00167-005-0033-2 [CrossRef]
- Vundelinckx B, Bellemans J, Vanlauwe J. Arthroscopically assisted meniscal allograft transplantation in the knee: a medium-term subjective, clinical, and radiographical outcome evaluation. Am J Sports Med. 2010;38:2240–2247. doi:10.1177/0363546510375399 [CrossRef]
- Wirth CJ, Peters G, Milachowski KA, Weismeier KG, Kohn D. Long-term results of meniscal allograft transplantation. Am J Sports Med. 2002;30:174–181. doi:10.1177/03635465020300020501 [CrossRef]
- Samitier G, Alentorn-Geli E, Taylor DC, et al. Meniscal allograft transplantation: Part 1. Systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation. Knee Surg Sports Traumatol Arthrosc. 2015;23:310–322. doi:10.1007/s00167-014-3334-5 [CrossRef]
- Samitier G, Alentorn-Geli E, Taylor DC, et al. Meniscal allograft transplantation: Part 2. Systematic review of transplant timing, outcomes, return to competition, associated procedures, and prevention of osteoarthritis. Knee Surg Sports Traumatol Arthrosc. 2015;23:323–333. doi:10.1007/s00167-014-3344-3 [CrossRef]
- Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Is sport activity possible after arthroscopic meniscal allograft transplantation: midterm results in active patients. Am J Sports Med. 2016;44:625–632. doi:10.1177/0363546515621763 [CrossRef]
- Marcacci M, Marcheggiani Muccioli GM, Grassi A, et al. Arthroscopic meniscus allograft transplantation in male professional soccer players: a 36-month follow-up study. Am J Sports Med. 2014;42:382–388. doi:10.1177/0363546513508763 [CrossRef]
- Chalmers PN, Karas V, Sherman SL, Cole BJ. Return to high-level sport after meniscal allograft transplantation. Arthroscopy. 2013;29:539–544. doi:10.1016/j.arthro.2012.10.027 [CrossRef]
- Alentorn-Geli E, Vázquez RS, Díaz PÁ, Cuscó X, Cugat R. Arthroscopic meniscal transplants in soccer players: outcomes at 2- to 5-year follow-up. Clin J Sport Med. 2010;20:340–343. doi:10.1097/JSM.0b013e3181f207dc [CrossRef]
- Kocher MS, Tepolt FA, Vavken P. Meniscus transplantation in skeletally immature patients. J Pediatr Orthop B. 2016;25:343–348. doi:10.1097/BPB.0000000000000291 [CrossRef]
- Englund M, Roos EM, Lohmander L. Impact of type of meniscal tear on radiographic and symptomatic knee osteoarthritis: a sixteen-year followup of meniscectomy with matched controls. Arthritis Rheum. 2003;48:2178–2187. doi:10.1002/art.11088 [CrossRef]
- Verdonk PC, Demurie A, Almqvist KF, Veys EM, Verbruggen G, Verdonk R. Transplantation of viable meniscal allograft: survivorship analysis and clinical outcome of one hundred cases. J Bone Joint Surg AM. 2005;87:715–724.
Search Terms and Results for Each Databasea
|PICO Search Terms||MEDLINE||CINHAL||SPORTDiscus||Total|
|Meniscus transplantation AND return to play OR return to sport OR return to activity AND knee||830||325||555||1,710|
|Meniscus transplant AND return to play OR return to sport OR return to activity AND knee||829||325||555||1,709|
|Meniscus allograft AND return to play OR return to sport OR return to activity AND knee||830||325||556||1,171|
Study Design and Results of Included Studies
|Author (Year)||Study Design||N||Population||Mean Age (y)a||Months to Follow-upa||Return to Play Proportion (%)||Months to Return to Playa|
|Alentorn-Geli et al.16 (2010)||Retrospective case series, level IV||14||Competitive soccer players||28.1 ± 6.4||36 ± 16.2||12/14 (85.7%)||7.6 ± 3.6|
|Chalmers et al.15 (2013)||Retrospective case series, level IV||13||High school/collegiate level athletes||19.3 ± 1.9||40 ± 14.6||10/13 (77%)||16.5 ± 6.5|
|Kocher et al.17 (2016)||Retrospective case series, level IV||3||Adolescent athletes||12.6 ± 2.3||31 ± 20||2/3 (66.67%)||9 ± 0|
|Marcacci et al.14 (2014)||Prospective case series, level IIb||12||Professional soccer players||24.5 ± 3.6||36 ± 0||11/12 (92%)||10.3 ± 2.7|
|Total mean ± standard deviation||42||23.2 ± 3.9||36.9 ± 11.4||35/42 (83.3%)||11.2 ± 5.9|
Preoperative and Postoperative Lysholm and IKDC Subjective Scoresa
|Patient-Reported Outcome||Alentorn-Geli et al.16 (2010)||Chalmers et al.15 (2013)||Kocher et al.17 (2016)||Marcacci et al.14 (2014)|
| Preoperative||63.7||55 ± 16||N/A||67± 14|
| Postoperative||85.9||81 ± 13||55.7 ± 22.3||92 ± 10|
| Preoperative||52.2||43 ± 15||N/A||61.8 ± 16.3|
| Postoperative||82.2||77 ± 14||68.3 ± 4b||85.3 ± 9.8|
Article Quality Assessed Via the National Institutes of Health's Quality Assessment Tool for Case Series Studiesa
|Criteria||Alentorn-Geli et al.16 (2010)||Chalmers et al.15 (2013)||Kocher et al.17 (2016)||Marcacci et al.14 (2014)|
|Was the study question or objective clearly stated?||Yes||Yes||Yes||Yes|
|Was the study population clearly and fully described, including a case definition?||Yes||Yes||Yes||Yes|
|Were the cases consecutive?||Yes||Yes||Yes||Yes|
|Were the subjects comparable?||Yes||Yes||Yes||Yes|
|Was the intervention clearly described?||Yes||Yes||Yes||Yes|
|Were the outcome measures clearly defined, valid, reliable, and implemented consistently across all study participants?||Yes||Yes||Yes||Yes|
|Was the length of follow-up adequate?||Yes||Yes||Yes||Yes|
|Were the statistical methods well described?||Yes||No||No||Yes|
|Were the results well described?||No||Yes||No||Yes|
|Quality rating||9/9 (good)||8/9 (good)||8/9 (good)||7/9 (good)|