• young patients with a history of meniscectomy who have symptoms of pain and discomfort associated with early osteoarthrosis that is localized to the meniscus-deficient compartment
• those who are undergoing ACL reconstruction in whom a concomitant meniscal transplant is intended to provide increased stability
• young athletes with few symptoms in whom the allograft transplantation is intended to deter the development of osteoarthritis; due to the risks associated with this surgical procedure, prophylactic treatment is not frequently recommended

• Adolescent patients should be skeletally mature with documented closure of growth plates (e.g., 15 years or older). Adult patients should be too young to be considered an appropriate candidate for total knee arthroplasty or other reconstructive knee surgery (e.g., younger than 55 years)
• Disabling knee pain with activity that is refractory to conservative treatment
• Absence or near absence (more than 50%) of the meniscus, established by imaging or prior surgery
• Documented minimal to absent degenerative changes in the surrounding articular cartilage (Outerbridge Grade II or less)
• Normal knee biomechanics, or alignment and stability achieved concurrently with meniscal transplantation
  

Patients should exhibit symptoms of persistent disabling knee pain lasting at least 6 months that has not shown an adequate response to physical therapy and analgesic medications. Uncorrected misalignment and instability of the joint are contraindications. Therefore additional procedures, such as repair of ligaments or tendons or creation of an osteotomy for realignment of the joint, may be performed at the same time.

Severe obesity, e.g., body mass index (BMI) greater than 35 kg/m2, may affect outcomes due to the increased stress on weight bearing surfaces of the joint. Meniscal allograft transplantation is typically recommended for young active patients who are too young for total knee arthroplasty.

Effective in 2005, there is a CPT category I code specific to this procedure when performed arthroscopically:

29868: Arthroscopy, knee, surgical; meniscal transplantation (includes arthrotomy for meniscal insertion), medial or lateral

There is no CPT code for implantation of the ReGen Collagen Scaffold, but the American Academy of Orthopedic Surgeons’ Coding, Coverage and Reimbursement Committee feels that the meniscal transplantation CPT code 29868 is appropriate for this procedure.

BlueCard/National Account Issues

Plans may consider requiring prior approval or preauthorization for meniscal allograft.

At the time of a 1997 TEC Assessment, data regarding meniscal allograft transplantation were of poor quality. (1) For example, none of the studies presented clear comparisons of preoperative findings to postoperative results, and each study assessed outcomes differently. While definitive data were not available, poor results were reported in patients with Outerbridge grade III or IV osteoarthritis, or in those with unstable knees.

In terms of graft viability, the largest case series has been collected by CryoLife, a commercial supplier of cryopreserved allografts. However, these data were not available in the published peer-reviewed literature. As summarized by Johnson in a 1999 report, among 1,023 transplants, CryoLife reported graft survival of 93% when the meniscus is transplanted with a bone plug for fixation, compared to 67% without such fixation. (2) The method of determining graft viability, with either serial MRI scans or second-look arthroscopy, was not reported. Additional patient outcome information was posted on their company Web site, based on responses to patient questionnaires. (3)

In a case study of 23 patients, Rath and colleagues reported significant improvement in function and reduced pain as measured by the Short Form-36 scores after cryopreserved meniscal allograft transplantation for compartmental pain after total meniscectomy 2 to 8 years postoperatively. (4) However, the authors noted function remained limited, and 8 of 22 allografts tore during the study period and required total or partial meniscectomies. In a prospective study of 23 patients who underwent medial meniscal transplantation with reconstruction of the ACL, Wirth and colleagues reported better results in the 6 cases of preservation of deep-frozen allografts over lyophilized meniscal transplants at 3 and 14 years postoperatively. (5) However, no preoperative clinical outcomes were assessed. Noyes and colleagues reported on 38 patients receiving cryopreserved meniscal transplant. (6, 7) At a mean of 40 months postoperative follow-up, 27 (68%) and 13 (33%) patients had no pain or mild pain, respectively, and the meniscal grafts appeared normal in 17 knees (43%) but failed in 11 (28%) knees and were altered in 12 (30%). Interpretation of these results is limited since 16 knees also received concomitant osteochondral autograft transfer, and 9 had knee ligament reconstruction. The authors of this study noted further investigation is required to determine long-term transplant function and any chondroprotective effects. In 2 additional studies, Sekiya et al. (8) and Yoldas et al. (9) reported promising outcomes in 28 and 31 patients, respectively, receiving meniscal transplants and ACL reconstruction.

2006-2007 Update

A search of the MEDLINE database for the period of August 2005 through January 2007 identified a number of retrospective case series with isolated meniscal allograft.

Verdonk and colleagues reported long-term follow-up from 95% of their first 105 fresh cultured (viable) meniscal allografts performed from 1989–2001. (10) The indication for transplantation was moderate-to-severe pain in a younger patient (mean of 35 years, range 16 to 50 years old) who had undergone a previous total meniscectomy, was not old enough to be considered for a knee joint replacement, and had good alignment of the lower limb and a stable joint (some were corrected concomitantly). Postoperative clinical evaluation was conducted yearly; 2 subjects were lost to follow-up as a result of death unrelated to the transplant (these were carried forward). With failure defined as moderate or severe pain (occasional or persistent) or poor knee function (modified Hospital for Special Surgery score of less than 80), 70% of the viable allografts (39 medial, 61 lateral) survived at 10 years, the mean survival time was estimated at 11.6 years.

This group also published follow-up of at least 10 years with radiological imaging from their first 42 allografts (27 medial, 15 lateral, treated from 1989 to 1993). (11) Of the 41 patients, 7 (17%) were followed up at the time of total knee replacement (failures); these were characterized by progression in joint space width narrowing (by 1 or 2 grades) and Fairbank changes (by 1 or 2 grades). Twenty-five allografts were evaluated in 2004 (average of 12 years follow-up). Of the 32 cases evaluated (76% follow-up), joint space remained stable in 41% and Fairbank changes did not progress in 28%. Magnetic resonance imaging (MRI) showed absence of further femoral cartilage degeneration in 8 of 17 knees (47%) evaluated. No significant correlations were found between any of the measured radiological or MRI parameters clinical subscales. The investigators of these reports discuss the investigational nature of this procedure and suggest a need for a prospective long-term comparison (using both subjective and objective clinical outcome measures) of patients who are treated with a meniscal allograft and a control group of patients who have similar symptoms and clinical findings. (10, 11)

Sekiya and colleagues reported follow-up testing from 32 patients who underwent isolated lateral cryopreserved meniscal allograft transplantation. (12) Transplants prior to 1994 were secured with individual bone plugs (n =5), those after 1994 were secured with use of a bone bridge (n =12) or no bony fixation with nonabsorbable suture passed through transosseus tunnels (n =8), depending on surgeon preference. Twenty-five patients could be located for follow-up, 20 for postoperative radiographs, and 17 (53%) underwent complete follow-up with radiographs and examination. At an average duration of 3.3 years (range of 2 to 6 years), 96% of patients believed that their overall function and activity level were improved following surgery (13 greatly better, 7 somewhat better, 4 slightly better, and 1 somewhat worse). Radiographic evaluation showed that joint space narrowing did not progress following transplantation (pre-operative 3.70 mm, latest follow-up 3.65 mm). This was compared with a change from 6.32 mm to 6.15 mm for the contralateral non-transplanted compartment. This report is limited by the loss to follow-up of nearly half of the patient group. In a recent review, Sekiya describes meniscal allograft transplantation as a salvage procedure. (13)

Cole et al reported follow-up evaluation of 39 patients, 21 menisci were transplanted in isolation, 19 were combined with other procedures. (14) From the whole group, 4 transplants (3 patients) failed early and another 7 had failed at follow-up, for a total 25% failure rate. The authors conclude that, “meniscus transplantation alone or in combination with other reconstructive procedures results in reliable improvements in knee pain and function at minimum 2-year follow-up. Longer term studies are necessary to determine if transplantation can prevent the articular degeneration associated with meniscectomy.”

Heckman and colleagues conclude in their review that, “For patients in whom meniscus function has been lost from prior meniscectomy, the short-term results of meniscus transplantation are encouraging, as many patients demonstrate improvement in knee function and pain relief in the affected compartment. However, the long-term function of this operation remains questionable, as the transplant appears to undergo remodeling, which results in alterations in collagen fiber architecture required for load-sharing and survival.” (15) Eriksson also notes that although meniscus transplantation holds promise for the younger patient, transplant procedures are evolving. (16)

2008 Update

This policy was updated with a search of the MEDLINE database for the period of February 2007 through March 2008. The updated policy was sent out for clinical input (see below), which was subsequently incorporated into the 2008 policy update.

Matava conducted a systematic review of the available literature; none of the 15 studies identified could be classified as Level I or Level II (prospective controlled comparisons), 3 studies qualified as Level III (retrospective comparisons); the 12 remaining studies were retrospective case series. (17) The primary indication for meniscal allograft transplantation in these studies was complete or near-complete meniscectomy with pain in the involved compartment, and before the development of moderate to severe arthrosis (less than 2 to 3 mm of joint space narrowing and/or limited chondral wear) in a young (less than 50 years of age) active patient. Lower extremity malalignment and/or ligamentous instability have been associated with meniscal transplantation failure, and thus were treated (e.g., osteotomy or ACL repair) before or at the time of the transplantation. Twelve studies used validated outcome measures, with second-look arthroscopy conducted in some of the patients in 11 studies. “Success” rates were usually over 60% (ranging from 13% to 100%), with more recent series reporting short-term favorable outcomes (based on pain, function, and patient satisfaction) in about 85% of their patient cohorts (generally 20 to 30 patients per cohort). Up to 26% reoperation rates for allograft tears in addition to other complications were reported. Matava et al noted that fresh frozen or cryopreserved grafts were associated with the highest success rates and the least risk for biomechanical degradation or disease transmission.

Hommen et al reported 10-year follow-up on 20 of 22 (91%) consecutive patients who received cryopreserved meniscus allografts. (18) Twenty-four concomitant procedures were performed in 15 of the patients, including ACL reconstruction or revision (n =10), high tibial osteotomy (n =2), and lateral retinaculum release (n =3). Forty additional surgical procedures were performed on 17 patients (85%) after transplantation; these included manipulation under anesthesia, arthroscopic synovectomy for postoperative arthrofibrosis, and additional meniscus-related procedures. The 10-year graft survival/success rate was 45%, with 5 allograft failures identified on second-look surgery, 5 allografts with grade III tears identified on magnetic resonance imaging (MRI), and 4 patients reporting no improvement. Of 15 patients with follow-up radiographs, 10 (67%) had narrowing (from 5.2 mm at baseline to 4.0 mm at follow-up) and 12 (80%) had progression of the Fairbank degenerative joint disease score (0.5 at baseline to 1.3 at follow-up) in the transplanted tibiofemoral compartment. Twenty-year follow-up was reported for 5 patients who had received a deep frozen meniscal allograft along with other procedures on the knee. (19) At 20-year follow-up MRI revealed shrinkage of the transplants with very small rims of the meniscus; the remaining meniscal tissue showed degenerative changes. The average Lysholm score at 20-year follow-up was 74 points (individual scores of 97, 95, 88, 70, and 21). As noted by Hommen et al, questions remain about whether meniscus grafts can delay or prevent the progression of degenerative changes and joint space narrowing. (18)

Combined meniscus transplantation and articular cartilage repair has been recently reported. Farr et al described outcomes from a prospective series of 36 patients who underwent autologous chondrocyte implantation (ACI) together with meniscal transplantation. (20) Four patients (11%) were considered failures before 2 years, and 3 were lost to follow-up (8%), resulting in 29 evaluable patients at an average of 4.5 years after surgery. The Lysholm score improved from an average score of 58 to 78; maximum pain decreased an average 33% (from 7.6 to 5.1). Excluding the 4 failures, 68% of their patients required additional surgeries; 52% had 1 additional surgery, and 16% required 2 or more additional surgeries. The most common procedures were trimming of periosteal overgrowth or degenerative rims of the transplanted meniscus. Another report described average 3.1 years of follow-up from a prospective series of 30 patients (31 procedures) who had undergone combined meniscal allograft transplantation with ACI (52%) or osteochondral allograft transplantation (OA; 48%). (21) The Lysholm score improved in both the ACI (from 55 to 79) and OA (from 42 to 68) groups; 48% of patients (60% ACI and 36% OA) were considered to be normal or nearly normal at the latest follow-up. Patients treated with OA were on average older (average 37 vs. 23 years) and with larger lesions (5.5 cm2 vs. 3.9 cm2). Two patients were considered failures (7%) and 5 (17%) underwent subsequent surgery. Although results seem promising, evidence is currently insufficient to permit conclusions regarding the effect of combined transplantation-implantation procedures on health outcomes.

Clinical Input Received through Physician Specialty Societies and Academic Medical Centers

In response to requests, input was received from one physician specialty society and 3 academic medical centers while this policy was under review in 2008. While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process, through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted. Although long-term effects on joint space narrowing are unknown, all of the reviewers considered this procedure to be beneficial in selected patients, with evidence of short to intermediate pain relief when performed in younger patients with a prior meniscectomy who have disabling knee pain. Contraindications were noted as uncorrected instability, uncorrected malalignment, and the presence of significant articular disease.

2009 Update

An updated literature search using the MEDLINE database was performed through August 2009. A small case series with 7 patients described positive results at 24-month follow-up for combined treatment with meniscal transplantation, chondral repair (including microfracture, osteochondral autograft transfer, osteochondral allograft transplantation or autologous chondrocyte implantation), and osteotomy. (24) Longer follow-up with a larger number of subjects is needed to evaluate the health outcome from combined treatments. In a study by van der Wal and colleagues, minimum 9-year follow-up was conducted by telephone for 57 patients (63 allografts) who had previously received a cryopreserved meniscal allograft. (25) The mean interval between total meniscectomy and meniscal allograft transplantation was 16 years (range, 2-33) and the mean age of the patients was 39 years (range, 26-55) at the time of transplantation. Eleven patients could not be contacted (2 had died), although 3 were known to have had total knee arthroplasty (TKA) and were included as failures. Thus, follow-up information was available for 49 of the 57 patients (86%) at an average 14 years (range, 9-18) after the procedure. Overall, 29% of the grafts had failed, with 21% converted to TKA at a mean follow-up of 11 years (range, 6-17). Failure rates were somewhat greater for medial (35%) than for lateral allografts (25%), with 67% of the failed medial allografts in an anterior cruciate ligament (ACL)-insufficient knee (an exclusion criterion later in the series). A long-term survival rate of 52.5% was observed after 16 years of follow-up. Lysholm functional scores were available preoperatively, at short-term (3 years), and at long-term follow-up for 81% of the patients; these improved from a mean of 36 (poor) to 79 points (fair) at short-term, declining to 61 points (fair for men and poor for women) at long-term follow-up. Lysholm scores were similar for those patients who had retained the meniscal allograft (61.1 points, range of 21-91, n = 33) and those who had converted to TKA (61.3 points, range of 18-100, n = 10). The authors concluded that for the goal of delaying the need for TKA, patients younger than 50 years with normally aligned, stable knee joints with sufficient ACLs are the best candidates for meniscal allograft transplantation.

Collagen Meniscus Implant

In 2006, a German research group published initial results from a randomized trial that compared high tibial valgus osteotomy alone with osteotomy plus a collagen meniscus implant in 60 patients with subtotal loss of the medial meniscus. (26) Arthroscopy on the first 23 of 30 patients with a collagen implant at 8-18 months post-surgery showed complete healing in 8 patients (35%), partial healing in 7 (30%; requiring resection of the posterior part of the implant), and poor results with only small remains of the collagen implant left in 8 patients (35%). Complications included implantation in insufficiently vascularized tissue, sutures cutting into the implant, inadequate fixation to the rim, destruction of the implant in an unstable knee joint or with premature loading post-operatively, allergic reaction to the xenogenic collagen implant, avulsion of the implant with joint blocking, and infection. Assessment of pain and function (Lysholm, International Knee Documentation Committee, subjective pain scores) showed slight and non-significant differences in comparison with the 16 patients treated with correction osteotomy only. Longer follow-up on all 60 patients is reported to be continuing.

Data provided to the FDA in support of the 510(k) application for the Menaflex collagen meniscus implant included a prospective, randomized multicenter clinical trial (26 surgeon-investigators from 16 sites) that was conducted under an investigational device exemption (IDE) and published in 2008. (27) The study involved 311 patients, randomized and analyzed separately for those with no prior surgery (acute group, n = 157) and those who had from 1 to 3 prior meniscal procedures (chronic group, n = 154). Included were patients 18 to 60 years of age who had an irreparable injury to or previous partial loss of one medial meniscus, with an intact rim. The involved knees had to be in neutral alignment, and patients with a full-thickness (Outerbridge Grade-IV) chondral lesion were excluded from the study, as were patients with posterior cruciate ligament insufficiency. Patients within the acute and chronic arms were randomized to receive the collagen meniscus implant or be treated with a partial meniscectomy only. Control patients (partial meniscectomy only) underwent standard physical therapy only. Patients receiving a collagen meniscus implant wore a knee brace that was locked in full extension for 6 weeks and were required to be non-weight-bearing with crutches for 2 weeks. The brace was removed 3 to 4 times per day to perform self-assisted passive range-of-motion exercises. Full weight-bearing and unlimited active and passive range-of-motion exercises were initiated after 6 weeks. Second-look arthroscopy with biopsy at one year was performed for all patients who received a collagen meniscus implant (acute and chronic); 141 of 160 patients in the 2 groups (88%) had arthroscopy. Patients underwent frequent clinical follow-up examinations over 2 years and completed validated outcomes questionnaires for up to 7 years (Lysholm functional score, Tegner activity scale and pain on a visual analog scale). At an average follow-up of 59 months (range, 16-92), new tissue was reported to appear grossly meniscus-like and integrate with the meniscus rim, with about 50% of the defect filled (45% in the acute group and 58% in the chronic group). There were no differences between the implant and control groups for pain, Lysholm and self-assessment scores. Only Tegner activity scores in the chronic arm were significantly different, with patients in the implant group reporting regaining 42% of their lost activity level, compared to a 29% regain in activity reported by controls (p = 0.02). Implant patients in the chronic group underwent significantly fewer non-protocol reoperations (8 vs. 15) compared to controls, although the report did not indicate whether procedures other than a “re-look” were performed during the one-year protocol scheduled reoperation. No differences were detected between the 2 treatment groups in the acute arm of the study, with 5 reoperations in each group. Kaplan-Meier analysis, which was estimated at 5 years due to the low number of patients at risk, suggested a modest increase in survival in the chronic group who had received a collagen implant compared to controls (about 90% vs. 80%). Additional studies with longer follow-up are needed to fully evaluate the health benefit of this new collagen meniscus implant for potential use in a relatively common orthopedic condition.

Summary

Meniscal allograft transplantation, performed in combination with other surgical interventions, appears to improve symptoms in some patients with a prior meniscectomy who are considered too young to undergo total knee replacement. Evidence consisting primarily of retrospective case series indicates that this procedure may produce short to intermediate-term pain relief in selected patients. The literature does not permit conclusions concerning the effect of meniscal transplantation on the progression of degenerative changes and joint space narrowing. (18, 19, 22)

Meniscal allograft transplantation is associated with a high number of complications, including tears of the transplanted meniscus, displacement, or arthrofibrosis, and careful selection of patients and surgical technique appear to be critical for success of this procedure. (17, 18) For example, one review concludes that success depends on performing the procedure with appropriate indications, using appropriate-sized menisci and meticulous technique. (22) Another states that “patients who meet criteria for meniscus allograft but have instability, malalignment or focal cartilage defects, may be candidates for transplantation as well as procedures to correct associated pathology. Such major interventions must, at present, be considered salvage procedures, and we do not recommend that they be performed casually or by surgeons without extensive experience and expertise in complex knee reconstruction.” (23)

The collagen meniscus implant, which was cleared for marketing by the FDA in 2009, has shown promise in terms of arthroscopic examination of tissue integration at short-term follow-up in some patients. In contrast, average improvements in clinical outcomes have been reported in the range of marginal to none when compared with control procedures at short-term follow-up. Longer follow-up is needed to determine whether implantation of a collagen scaffold is able to slow joint degeneration, reduce pain, or otherwise improve the net health outcome at longer durations. Controlled studies comparing the collagen meniscus implant with allograft transplantation would also be of value in evaluating the health benefit of this procedure. The evidence at this time is insufficient to permit conclusions concerning the effect of this technology on health outcomes. Therefore, the collagen meniscus implant is considered investigational.

Medicare National Coverage

As of August 27, 2009, CMS has opened a national coverage determination to complete a thorough review of the evidence to determine if the collagen meniscus implant is reasonable and necessary for coverage under the Medicare program. (28) A proposed decision memo is expected on February 27, 2010 with a national coverage announcement by May 28, 2010.

References:

1. 1997 TEC Assessment, Tab 14.
2. Johnson DL, Bealle D. Meniscal allograft transplantation. Clin Sports Med 1999; 18(1):93-108.
3. CryoLife Web site: www.cryolife.com
4. Rath E, Richmond JC, Yassir W et al. Meniscal allograft transplantation. Two- to eight-year results. Am J Sports Med 2001; 29(4):410-4.
5. Wirth CJ, Peters G, Milachowski KA et al. Long-term results of meniscal allograft transplantation. Am J Sports Med 2002; 30(2):174-81.
6. Noyes FR, Barber-Westin SD, Rankin M. Meniscal transplantation in symptomatic patients less than fifty years old. J Bone Joint Surg Am 2004; 86-A(7):1392-404.
7. Noyes FR, Barber-Westin SD, Rankin M. Meniscal transplantation in symptomatic patients less than fifty years old. J Bone Joint Surg Am 2005; 87 Suppl 1(pt 2):149-65.
8. Sekiya JK, Giffin JR, Irrgang JJ et al. Clinical outcomes after combined meniscal allograft transplantation and anterior cruciate ligament reconstruction. Am J Sports Med 2003; 31(6):896-906.
9. Yoldas EA, Sekiya JK, Irrgang JJ et al. Arthroscopically assisted meniscal allograft transplantation with and without combined anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 2003; 11(3):173-82.
10. Verdonk PC, Demurie A, Almqvist KF et al. Transplantation of viable meniscal allograft. Survivorship analysis and clinical outcome of one hundred cases. J Bone Joint Surg Am 2005; 87(4):715-24.
11. 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(8):694-706.
12. Sekiya JK, West RV, Groff YJ, et al. Clinical outcomes following isolated lateral meniscal allograft transplantation. Arthroscopy 2006; 22(7):771-80.
13. Sekiya JK, Ellingson CI. Meniscal allograft transplantation. J Am Acad Orthop Surg. 2006; 14(3):164-74.
14. Cole BJ, Dennis MG, Lee SJ, et al. Prospective evaluation of allograft meniscus transplantation: a minimum 2-year follow-up. Am J Sports Med 2006; 34(6):919-27.
15. Heckmann TP, Barber-Westin SD, Noyes FR. Meniscal repair and transplantation: indications, techniques, rehabilitation, and clinical outcome. J Orthop Sports Phys Ther 2006 Oct;36(10):795-814.
16. Eriksson E. Meniscus transplantation. Knee Surg Sports Traumatol Arthrosc 2006; 14(8):693.
17. Matava MJ. Meniscal allograft transplantation: a systematic review. Clin Orthop Relat Res 2007; 455:142-57.
18. Hommen JP, Applegate GR, Del Pizzo W. Meniscus allograft transplantation: ten-year results of cryopreserved allografts. Arthroscopy 2007; 23(4):388-93.
19. von Lewinski G, Milachowski KA, Weismeier K et al. Twenty-year results of combined meniscal allograft transplantation, anterior cruciate ligament reconstruction and advancement of the medial collateral ligament. Knee Surg Sports Traumatol Arthrosc 2007; 15(9):1072-82.
20. Farr J, Rawal A, Marberry KM. Concomitant meniscal allograft transplantation and autologous chondrocyte implantation: minimum 2-year follow-up. Am J Sports Med 2007; 35(9):1459-66.
21. Rue JP, Yanke AB, Busam ML, et al. Prospective evaluation of concurrent meniscus transplantation and articular cartilage repair: minimum 2-year follow-up. Am J Sports Med 2008; 36(9):1770-8.
22. Amendola A. Knee osteotomy and meniscal transplantation: indications, technical considerations, and results. Sports Med Arthrosc 2007; 15(1):32-8.
23. Lubowitz JH, Verdonk PC, Reid JB 3rd et al. Meniscus allograft transplantation: a current concepts review. Knee Surg Sports Traumatol Arthrosc 2007; 15(5):476-92.
24. Gomoll AH, Kang RW, Chen AL et al. Triad of cartilage restoration for unicompartmental arthritis treatment in young patients: meniscus allograft transplantation, cartilage repair and osteotomy. J Knee Surg 2009; 22(2):137-41.
25. van der Wal RJ, Thomassen BJ, van Arkel ER. Long-term clinical outcome of open meniscal allograft transplantation. Am J Sports Med 2009 Jun 19 [Epub ahead of print].
26. Linke RD, Ulmer M, Imhoff AB. Replacement of the meniscus with a collagen implant (CMI). Oper Orthop Traumatol 2006; 18(5-6):453-62.
27. Rodkey WG, DeHaven KE, Montgomery WH 3rd et al. Comparison of the collagen meniscus implant with partial meniscectomy. A prospective randomized trial J Bone Joint Surg Am 2008; 90(7):1413-26.
28. Centers for Medicare and Medicaid Services (CMS). National Coverage Analysis Tracking Sheet for Collagen MENISCUS Implant (CAG-00414N) Available at: http://www.cms.hhs.gov/mcd/viewtrackingsheet.asp?id=235. Last viewed September 2009.

Allograft, Meniscal
Meniscal Allograft
Transplantation, Meniscal