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Meniscus Allograft Transplantation: Ten-Year Results of Cryopreserved Allografts
Meniscus Allograft Transplantation: Ten-Year Results of Cryopreserved Allografts Jan Pieter Hommen, M.D., Gregory R. Applegate, M.D., and Wilson Del Pizzo, M.D.
Purpose: We report the results of cryopreserved meniscus allograft transplantations with 10 or more years of follow-up. Methods: Fourteen medial and 8 lateral meniscus allografts were evaluated with a mean follow-up of 141 months (range, 115 to 167 months). The clinical outcome and failure rate was evaluated by use of a Lysholm score and modified pain score in 22 patients. The results of radiographic and magnetic resonance imaging (MRI) analysis were reported in 15 and 7 patients, respectively. Results: Overall, 25% of medial allografts and 50% of lateral allografts failed. The combined failure rate was 35%. There was a 90% improvement in Lysholm scores, as well as pain scores. There were no discernible Lysholm or pain score differences for both lateral and medial allografts. Furthermore, there was no discernible difference in both Lysholm and pain scores between bone plug and soft-tissue methods of graft fixation. Ten of fifteen allografts showed radiographic joint space narrowing, and twelve had progression of degenerative joint disease. On MRI, all grafts had moderate meniscus shrinkage and five had grade III signal intensities. Eighty-five percent of patients underwent subsequent procedures, 5 of whom required total allograft resection and 2 of whom required partial allograft resection. One allograft required repair. Conclusions: Although transplantation of cryopreserved allografts improved knee pain and function, the average knee function was fair at long-term follow-up. Fifty-five percent of allografts failed when failure criteria for second-look surgery, knee improvement surveys, and MRI were added to Lysholm and pain score failures. The protective benefits of meniscus allografts remain debatable, and inferences cannot be made from this study. Level of Evidence: Level IV, therapeutic case series. Key Words: Meniscus—Allograft—Transplantation—Knee—Outcome—Arthroscopy—Arthritis.
T
he meniscus plays a crucial role in the biomechanical homeostasis of the knee joint. It functions to provide shock absorption, load bearing, load transmission, lubrication, and joint congruency. Me-
From the Orthopaedic Institute at Mercy Hospital (J.P.H.), Miami, Florida; and San Fernando Valley MRI (G.R.A.) and Southern California Orthopaedic Institute (W.D.P.), Van Nuys, California, U.S.A. The authors report no conflict of interest. Address correspondence and reprint requests to Jan Pieter Hommen, M.D., Orthopaedic Institute at Mercy Hospital, Suite 4008, 3659 S Miami Ave, Miami, FL 33133, U.S.A. E-mail: [email protected] © 2007 by the Arthroscopy Association of North America 0749-8063/07/2304-5325$32.00/0 doi:10.1016/j.arthro.2006.11.032 NOTE: To access the supplementary tables accompanying this report, visit the April issue of Arthroscopy at www. arthroscopyjournal.org.
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niscal procedures comprise more than 50% of the 1.5 million knee arthroscopies performed each year.1 Over the past 30 years, numerous studies have shown the increased risk of tibiofemoral arthrosis after meniscectomy. This has led to an increased emphasis on meniscus preservation techniques. Not all meniscus tears, however, are amenable to limited resection or repair, leaving the surgeon with few options, especially for the younger patient. When the meniscus is completely lost, transplantation of a meniscus allograft has been a therapeutic option with favorable improvements in knee pain and functionality. Meniscus transplants presumably increase the joint contact area, thereby lowering the joint contact peak stress. Allograft transplantation remains an evolving area and lacks general consensus regarding indications, tissue processing, secondary sterilization, surgical technique, and long-term function and efficacy.2-5 The long-term effects of meniscus allografts are difficult to
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 23, No 4 (April), 2007: pp 388-393
CRYOPRESERVED MENISCUS ALLOGRAFT interpret because of the paucity of long-term studies and the lack of standardized graft processing and implantation techniques. There are many studies with follow-up ranges exceeding 5 years3,4,6-8 and several reports with ranges of more than 10 years4,9,10; however, most of these studies are limited by mean follow-up lengths of less than 1 year4,11 or less than 5 years.3,4,6,7,9,10 Wirth et al.12 reported the only study to date with a mean follow-up of 10 or more years (14 years); however, they used lyophilized and deep-frozen meniscus allografts. When considering only cryopreserved allograft studies, the study with the longest follow-up was performed by van Arkel and de Boer,13 with a mean follow-up of 5 years (range, 4 to 126 months). The purpose of our study was to determine the long-term follow-up results (ⱖ10 years) of 22 consecutive, cryopreserved meniscus allografts.
METHODS Patients Between 1991 and 1995, the senior surgeon transplanted 22 sequential meniscus allografts in 22 patients. The mean age and median age of the patients at the time of transplantation were 32 years and 31 years, respectively, with a range of 17 to 46 years. One meniscus allograft was lost to follow-up, and one patient refused to participate in the study. The remaining 20 patients (20 allografts) had a mean duration of follow-up of 141 months (SD, 17.1 months), with a range of 115 to 167 months (Table 1, online only, available at www.arthroscopyjournal.org). Seven patients were unable to return for follow-up and were assessed by their local orthopaedic surgeon. Fourteen medial and eight lateral allografts were transplanted into thirteen men and nine women. Before the meniscus allograft procedure, the patients underwent a combined 47 operations. The indications for meniscus transplantation were prior meniscectomy, age less than 50 years, moderate to severe tibiofemoral pain, mild to advanced arthrosis, and 2 mm of tibiofemoral joint space or greater on 45° weight-bearing posteroanterior radiographs. Patients with surgically correctable malalignment or ligament instability were also candidates. Exclusion criteria included a history of knee infection, advanced arthrosis with flattening of the femoral condyle, concavity of the tibial plateau, malalignment, arthrofibrosis, and osteophytes that prevented anatomic seating of the meniscus allograft.3
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Subjective and Functional Evaluation In addition to a detailed physical examination, patients completed a Lysholm knee score and a modified pain score before surgery. Postoperative evaluation was performed by use of Lysholm, Tegner, and International Knee Documentation Committee (IKDC 2000) scores, as well as Short Form 12 (SF-12) and modified pain scores. Furthermore, patients were asked to complete a knee survey rating the improvement of the knee. Arthroscopic Classification Arthroscopic assessment of the articular cartilage was performed at the time of transplantation and classified according to the Outerbridge grading system. Radiographic Evaluation Preoperative and postoperative lower limb tibiofemoral joint spaces were evaluated via standing bilateral posteroanterior 45° views by a single observer. Similarly, the Fairbank arthrosis classification was determined for the preoperative and postoperative radiographs. Fifteen patients had postoperative radiographs available for measurement. Magnetic Resonance Imaging Studies Seven allografts underwent magnetic resonance imaging (MRI) without arthrography. The affected tibiofemoral compartment was categorized via qualitative analysis as having no, mild, moderate, or severe arthrosis. The meniscal signal changes were classified as normal, grade 1, grade 2, or grade 3. Allograft size reduction was graded as mild, moderate, or severe. Cumulative Meniscus Failures Patients who had a poor Lysholm score (⬍65) or who had no improvement in the pain score were considered failures. In a separate assessment, these pa1 tients were combined with surgical failures (requiring ⬎2 allograft meniscectomy), MRI failures (grade III signal), and patients reporting no improvement in subjective knee survey scores. Surgical Technique All patients underwent transplantation with cryopreserved meniscus allografts procured by CryoLife Orthopaedics (Marietta, GA). Allografts were sized by use of standing anteroposterior and lateral radiographs allowing for magnification. All knees underwent arthroscopic assessment to determine the status of the
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meniscus, ligaments, and cartilage. In those knees for which transplantation was indicated, the meniscus was resected, leaving a bleeding peripheral rim. The grafts were introduced through a medial or lateral parapatellar arthrotomy. When needed, the medial epicondyle underwent osteotomy and was later restored with a screw or staple fixation. Of the 12 medial menisci, 3 were secured via a double bone plug technique2 and 8 were secured via an all-suture technique.10 One medial meniscus was implanted via a posterior bone plug and anterior suture fixation because of improper seating of the anterior bone plug. Two of the eight lateral menisci were secured via a single bone plug technique by use of a trough,2 and five were placed via an all-suture technique. One lateral meniscus was implanted via a double bone plug technique. A posteromedial or posterolateral corner counter-incision was used to assist in retrieving and suturing the meniscus via an arthroscopic inside-out suture technique with vertical polydioxanone surgical sutures (PDS II; Ethicon, Somerville, NJ). A Meniscus Arrow (Linvatec, Largo, FL) was used in one allograft to secure the allograft to the meniscus rim. In 15 patients, 24 concomitant procedures were performed (Table 2, online only, available at www.arthroscopyjournal.org). Statistical Analysis Statistical analysis was performed by use of 2, analysis of variance, Fisher exact, paired t, and MannWhitney tests as indicated for the data. P ⬍ .05 was considered statistically significant. RESULTS Clinical Outcome There was a significant improvement in the overall mean Lysholm score, from 53 (range, 23 to 78) preoperatively to 75 (range, 51 to 100) postoperatively (P ⬍ .001) (Table 3, online only, available at www. arthroscopyjournal.org). The postoperative scores had improved in 18 (90%) of the 20 allografts, with 1 excellent, 5 good, 8 fair, and 6 poor scores. Those patients with worsened scores had lateral allografts, being split evenly between those with bone plug fixation and those with soft-tissue fixation. The 6 poor postoperative Lysholm scores (⬍65) were distributed evenly between the lateral and medial allografts (Table 4, online only, available at www.arthroscopyjournal.org). Patients with poor postoperative Lysholm scores had correspondingly lower preoperative Lysholm scores compared with the
other patients (42 and 57, respectively; P ⫽ .0259). However, both groups had significant improvements in postoperative scores (60 [P ⫽ .0133] and 82 [P ⬍ .0003], respectively). The mean pain score improved from 4.8 (range, 3 to 7) preoperatively to 2.4 (range, 0 to 6) postoperatively (P ⬍ .001) (Table 3, online only, available at www.arthroscopyjournal.org). The pain scores improved in 18 of 20 allografts (90%). One medial allograft, with bone plug fixation, had a worse postoperative pain score, and one lateral allograft, with soft-tissue fixation, had no change in pain score. The postoperative IKDC, Tegner, SF-12, and subjective scores are shown in Table 5 (online only, available at www.arthroscopyjournal.org). Thirteen patients reported that the knee was much improved, one was moderately improved, two were slightly improved, and four had no improvement (Table 5, online only, available at www.arthroscopyjournal.org). There was no significant difference between the lateral and medial allografts in terms of postoperative Lysholm and pain scores (Table 3, online only, available at www.arthroscopyjournal.org). The bone plug and soft-tissue fixation methods yielded similar postoperative Lysholm results (73 and 77, respectively; P ⫽ .3228) (Table 6, online only, available at www.arthroscopyjournal.org). Likewise, the 2 methods yielded similar postoperative pain scores (2.7 and 2.2, respectively; P ⫽ .7653) (Table 7, online only, available at www.arthroscopyjournal. org). Only 1 patient, who had poor Lysholm and IKDC scores, would not undergo this procedure again and would also not recommend this procedure to others. A combined 24 concomitant procedures were performed in 15 patients. Patients with higher Outerbridge cartilage injury scores tended to have an increased number of concomitant procedures. The mean Lysholm and pain scores were improved for the subgroups of concomitant procedures, although it was difficult to draw conclusions from these data because of the small study sample size (Table 8, online only, available at www.arthroscopyjournal.org). There was a trend toward smaller Lysholm score improvements in those patients with 3 additional procedures than in those with no additional procedures. Workers’ Compensation patients had similar significant improvements in mean Lysholm scores (54 to 76, P ⫽ .0044) and pain scores (4.5 to 2.1, P ⫽ .0049) postoperatively relative to non–Workers’ Compensation patients (52 to 76 [P ⫽ .0024] and 4.9 to 2.6 [P ⫽ .0001], respectively).
CRYOPRESERVED MENISCUS ALLOGRAFT Arthroscopic Classification According to the Outerbridge classification, the cartilage score for the affected compartment at the time of allograft surgery was grade 0 in 4 patients, grade 1 in 0, grade 2 in 6, grade 3 in 8, and grade 4 in 2. Although a lower Outerbridge score trended toward a better postoperative Lysholm score, drawing conclusions based on these data was difficult because of the sample size. Radiographic Findings Of the 15 patients with follow-up radiographs, 10 had narrowing of the involved tibiofemoral compartment (mean, 5.15 ⫾ 1.0 mm preoperatively and 4 ⫾ 1.1 mm postoperatively; P ⫽ .0002). Those with narrowing tended to have lower mean postoperative Lysholm scores (72 v 92). Twelve patients had a progression of the Fairbank degenerative joint disease score in the transplanted compartment from 0.5 ⫾ 0.6 to 1.3 ⫾ 0.9 (P ⫽ .0001). These patients appeared to have a lower postoperative Lysholm score (74 v 81 in patients without progression, P ⫽ .2994).
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allograft, which originally had suture fixation of the anterior and posterior horns and Meniscus Arrow (Linvatec) fixation of the peripheral rim, required subsequent meniscus repair at 5 years for a peripheral rim detachment. No other patient in this study had Meniscus Arrow peripheral rim fixation. Two partial menis1 cectomies (⬍2 of meniscus) and 5 total meniscecto1 mies (⬎2 of meniscus) were performed. Cumulative Meniscus Failures By use of a Lysholm score of less than 65 and no improvement in pain score as clinical criteria for failure, there were 7 allograft failures (35%). Failure occurred in 3 of 12 medial allografts (25%) and 4 of 8 lateral allografts (50%) (Table 5, online only, available at www.arthroscopyjournal.org). If we combine these results with failures from second-look surgery (5 total surgical failures) and MRI studies (5 allografts with grade III tears), as well as patients with reports of no improvement on the knee survey (4 allografts), the 10-year survival rate is 45% (9 of 20), with failures in 58% of medial allografts (7 of 12) and 50% of lateral allografts (4/8).
MRI Findings Of the 7 patients who underwent MRI, 5 had a grade III tear of the posterior horn of the allograft. All 5 patients had corresponding joint line tenderness and a McMurray sign. One underwent subsequent total meniscectomy. Of the allografts, 4 had moderately truncated mid zones and 2 had moderately diminutive anterior horns. One allograft had a severely truncated mid zone. The cartilage classification was normal in 1, mild in 2, moderate in 3, and severe in 1. Postoperative mean Lysholm scores relative to the corresponding 4 grades were as follows: 70, 81, 75, and 57, respectively. Interpretation of these data was limited because of the small sample size. Subsequent Knee Surgeries A total of 40 subsequent surgical procedures were performed in 17 patients. Other than those requiring additional meniscus work, there were 17 complications. Eleven allografts developed postoperative arthrofibrosis requiring arthroscopic synovectomy and manipulation under anesthesia. Medial epicondylectomy did not correlate with the development of arthrofibrosis (P ⫽ .37). Two patients underwent removal for painful, prominent anterior cruciate ligament tibial hardware. In one patient, scar revision was required and developed complex regional pain syndrome. One
DISCUSSION Historically, the first meniscus replacement surgery dates back to 1916, when Lexer performed autogenous fat tissue interposition arthroplasty.4 The first free-meniscus transplantations were reported by Milachowski and Wirth in 1984.12 Since then, numerous studies and reviews have been reported related to meniscus transplantation. Data from 2002 suggested that more than 4,000 meniscus transplants had been performed since 1991, with more than 800 transplants performed per year. Meniscus allograft surgery remains an evolving area with considerable debate as to proper tissue processing, implantation, indications, and potential long-term outcome. The methods of tissue processing and preservation have impacted meniscus allograft survival. Several excellent reviews have discussed the merits and drawbacks of each method.1,2,4,5 The differences in meniscus preservation techniques have made comparison between studies difficult. Recent studies have shown that the survival rate for cryopreserved meniscus allografts is approximately 70%. The longest follow-up for cryopreserved menisci has been reported by van Arkel and de Boer,13 with a mean of 5 years and a range of 0.3 to 10.5 years. They reported cumulative survival rates for lateral, medial, and combined allo-
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grafts of 76%, 50%, and 67%, respectively. Graft failure criteria were persistent pain, an unsuccessful Knee Assessment Scoring System result, a poor Lysholm score, and a detached or torn allograft at second-look arthroscopy. Lateral grafts failed on average 53 months after implantation, whereas medial allografts failed at a mean of 25 months. Using Lysholm and pain score criteria for failure, our study showed a similar total survival rate of 65%, with survival rates of 50% for lateral allografts and 75% for medial allografts. If we apply failure criteria similar to those used in the study of van Arkel and de Boer13 (no improvement in pain score, poor Lysholm score, and surgical second-look failures), our study shows a 60% combined survival rate (50% lateral and 66% medial). We further attempted to show the total meniscus failure rate by combining our initial study failure criteria with known surgical failures, unimproved patient knee survey scores, and MRI failures and found a total survival rate of 45% (42% medial and 50% lateral). Our MRI data, though limited by the number of follow-up scans, seem to correlate with previous studies linking clinical and MRI results.5,6,13 In our study, patients with grade III allograft signals also had mechanical symptoms in the operative compartment. Because IKDC, Tegner, and SF-12 scores were not assessed preoperatively, they were not included. The ideal method for meniscus fixation remains a topic of debate. A review of the literature reveals no real discernible clinical difference between the bone plug and soft-tissue fixation methods.4 Cadaveric studies in human beings have shown that a secure, anatomic fixation with bone plugs attached to the anterior and posterior horn is essential to restore normal contact mechanics for both the medial and lateral menisci.4 The advantages of soft-tissue fixation include ease with sizing, anatomic positioning, and securing of the graft. The importance of anatomic placement of bone plugs and the adverse effect of nonanatomic placement on contact pressure patterns have been shown in cadaveric knees.4 Our study revealed no differences between fixation methods used; however, our sample size was limited, and a variety of implantation techniques were used. Whether meniscus grafts can delay or prevent the progression of degenerative changes and joint space narrowing also remains unclear.4,5,10 A significant number of knees in our study had a progression of compartment narrowing and degenerative joint disease. Garrett and Stevensen14 reported no significant decrease in joint space at 24 to 44 months’ follow-up.
However, studies with longer follow-up have shown radiographic progression. Rath et al.7 reported that the compartment space of 11 knees averaged 5.2 mm before surgery and 4.5 mm at 2 to 8 years’ follow-up. One patient lost more than 1 mm of joint space. Wirth et al.,12 with a mean follow-up of 14 years, showed evidence of degenerative changes on all 11 available radiographs. At 13 to 69 months of follow-up, Stollsteimer et al.15 found a mean of 1.7 mm of joint space narrowing in 10 of 22 patients. Ryu et al.,8 in a study with a minimum follow-up of 2 years, found joint space narrowing of 1 to 4 mm in 3 patients and no changes in 5 patients. Carter16 found evidence of progression in only 2 of 46 knees at a mean of 34.5 months. In studies in rabbits, Rijk5 concluded that meniscus grafts were unable to prevent the progression of arthritis after 1 year. Because radiographic follow-up was limited in our study, we are cautious in interpreting these results. This study has several limitations, including the lack of a prospective and randomized design with a control group. This study implemented several surgical techniques, reflecting the lack of a clear consensus for optimal graft fixation. Furthermore, meniscus allografts were implanted in knees with a variety of degenerative knee scores. Two patients with grade IV changes underwent the procedure in 1992, whereas eight with grade III changes underwent implantation between 1991 and 1995. Literature reports of poor outcomes in the setting of advanced degenerative arthrosis began to emerge in the mid 1990s.2,4,6,11 Inferences concerning the cartilage-protective effects and survivorship of the allografts should be made with caution. The purpose of this study is to report the long-term outcomes of 22 consecutive meniscus allograft transplantations, performed by a single surgeon, to treat a difficult problem in a young patient population with limited treatment alternatives.
CONCLUSIONS At 10-year follow-up, cryopreserved meniscus allografts improved knee pain and function; however, the average knee function was fair. Forty-five percent of allografts survived when failure criteria for secondlook surgery, knee improvement surveys, and MRI were added to Lysholm and pain score failures. The long-term chondral protective benefits of meniscus allografts remain debatable and cannot be inferred from this study.
CRYOPRESERVED MENISCUS ALLOGRAFT Acknowledgment: The authors acknowledge Richard D. Ferkel, M.D., Marc J. Friedman, M.D., and Loren Khoury for their assistance on this project.
8. 9.
REFERENCES 10. 1. Peters G, Wirth CJ. The current state of meniscal allograft transplantation and replacement. Knee 2003;10:19-31. 2. Cole BJ, Carter TR, Rodeo SA. Allograft meniscal transplantation: Background, techniques, and results. Instr Course Lect 2003;52:383-396. 3. Noyes FR, Barber-Westin SD, Rankin M. Meniscus transplantation in symptomatic patients less than fifty years old. J Bone Joint Surg Am 2004;86:1392-1404. 4. Rijk PC. Meniscal allograft transplantation—Part I: Background, results, graft selection and preservation, and surgical considerations. Arthroscopy 2004;20:728-743. 5. Rijk PC. Meniscal allograft transplantation—Part II: Alternative treatments, effects on articular cartilage, and future directions. Arthroscopy 2004;20:851-859. 6. Noyes FR, Barber-Westin SD. Irradiated meniscus allografts in the human knee: A two to five year follow up study. Orthop Trans 1995;19:417. 7. Rath E, Richmond JC, Yassir W, Albright JD, Gundogan F.
11. 12. 13. 14. 15. 16.
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Meniscal allograft transplantation. Two- to eight-year results. Am J Sports Med 2001;29:410-414. Ryu RK, Dunbar VWH, Morse GG. Meniscus allograft replacement: A 1-year to 6-year experience. Arthroscopy 2002; 18:989-994. Milachowski KA, Weismeier K, Wirth CJ. Homologous meniscus transplantation. Experimental and clinical results. Int Orthop 1989;13:1-11. 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. Veltri DM, Warren RF, Wickiewicz TL, O’Brien SJ. Current status of allograft meniscal transplantation. Clin Orthop Relat Res 1994:44-55. 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. van Arkel ER, de Boer HH. Survival analysis of human meniscal transplantations. J Bone Joint Surg Br 2002;84:227-231. Garrett JC, Stevensen RN. Meniscal transplantation in the human knee: A preliminary report. Arthroscopy 1991;7:57-62. Stollsteimer GT, Shelton WR, Dukes A, Bomboy AL. Meniscal allograft transplantation: A 1- to 5-year follow-up of 22 patients. Arthroscopy 2000;16:343-347. Carter TR. Meniscal allograft transplantation. Sports Med Arthrosc Rev 1999;7:51-62.
CRYOPRESERVED MENISCUS ALLOGRAFT TABLE 1.
Allograft
No.
M
F
Mean Age (yr) (Range)
Lateral Medial Total
8 12 20
4 9 13
4 3 7
35 (28-43) 30 (17-41) 32 (17-43)
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Meniscus Allograft Details
Bone Plug Fixation
Soft-Tissue Suture Fixation
Combination Fixation*
Mean Follow-up (mo) (Range)
Mean Outerbridge Classification (Range)†
3 3 6
5 8 13
0 1 1
131 (113-157) 146 (120-167) 140 (114-167)
2.25 (2-3) 2.15 (0-4) 2.2 (0-4)
Mean Preoperative Fairbank Classification (Range)‡ 0.75 (0-2) 0.25 (0-1) 0.45 (0-2)
*Posterior horn bone plug fixation and anterior horn soft-tissue suture fixation. †Outerbridge classification determined arthroscopically at the time of graft transplantation, where 0 indicates normal cartilage, 1 indicates cartilage with softening and swelling, 2 indicates a partial-thickness defect with fissures on the surface that do not reach subchondral bone or exceed 1.5 cm in diameter, 3 indicates fissuring to the level of subchondral bone in an area with a diameter of more than 1.5 cm, and 4 indicates exposed subchondral bone. ‡Radiographic Fairbank classification, where 0 indicates normal, 1 indicates mild, 2 indicates moderate, and 3 indicates severe.
TABLE 2.
Allograft
ACL Reconstruction
Revision ACL Reconstruction
Medial Lateral Total
8 1 9
1 0 1
Concomitant Procedures
HTO
Lateral Retinaculum Release
Lysis of Adhesions
Loose Body Removal
Capsular Plication
Chondroplasty of Femoral Condyle
Total
1 1 2
3 0 3
1 2 3
1 0 1
2 0 2
2 1 3
19 5 24
Abbreviations: ACL, anterior cruciate ligament; HTO, high tibial osteotomy.
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J. P. HOMMEN ET AL. TABLE 3.
Outcome Measures
Lysholm Score* (Range)
Pain Score† (Range)
Allograft
Preoperative
Postoperative
Preoperative
Postoperative
Lateral (n ⫽ 8) Medial (n ⫽ 12) Total (N ⫽ 20)
53 (23-78) 53 (28-77) 53 (23-78)
75 (51-100) 75 (62-94) 75 (51-100)
4.8 (3-6) 4.8 (3-7) 4.8 (3-7)
2.4 (1-4) 2.4 (0-6) 2.4 (0-6)
*A score of greater than 94 is excellent; 84 to 94, good; 65 to 83, fair; and less than 65, poor. †Ranging from 0 to 10 (where 0 indicates no pain and 10 indicates severe pain).
TABLE 4.
Meniscus Allografts With Poor Postoperative Scores
Surgical Subjective Mean Time Objective Failure Knee MRI to Total IKDC Subjective (n ⫽ 8)† Status Grade Surgical Score IKDC Lysholm Score: Not Combined III Failure (mo) (C or D) Score Score Signal Improved Failures‡ (range) (n ⫽ 13)* Total Partial (⬍70) (⬍65) Same Worsened Pain Score Versus Preoperative
Allograft Lateral (n ⫽ 8) Medial (n ⫽ 12) Total (N ⫽ 20)
3 3 6
1 0 1
0 1 1
2 4 6
5 3 8
3 2 5
3 0 3
65 (3-120) 78 (72-84) 70 (3-120)
1 4 5
1 3 4
4 (50%) 3 (25%) 7 (35%)
*In 13 patients, postoperative objective IKDC scores were available. †Eight patients underwent subsequent surgery for allograft pathology, where partial failure indicates that subsequent repair or partial meniscectomy (⬍1/2 of meniscus) was required and total failure indicates that subsequent meniscectomy (⬎1/2 meniscus) was required. ‡Combined failures include those patients with a Lysholm score of less than 65 and an unimproved or worsened pain score.
TABLE 5.
Postoperative Scores for Meniscus Allografts
Objective IKDC Score† (n ⫽ 13)
Allograft
Subjective IKDC Score* (N ⫽ 20) (Range)
A
B
C
Lateral (n ⫽ 8) Medial (n ⫽ 12) Total (N ⫽ 20)
77 (66-95) 77 (63-95) 77 (63-95)
1 1 2
1 2 3
5 3 8
SF-12 Score (N ⫽ 20) (Range)
Subjective Score‡ (N ⫽ 20)
D
Tegner Score (N ⫽ 20) (Range)
PCS
MCS
A
B
C
D
0 0 0
4.6 (2-9) 4.3 (1-6) 4.5 (1-9)
51 (43-57) 52 (43-56) 52 (43-57)
62 (51-66) 62 (57-66) 62 (52-66)
1 3 4
1 1 2
1 0 1
5 8 13
Abbreviations: PCS, physical comprehensive score; MCS, mental comprehensive score. *Excellent, 90 or greater; good, 80 to 89; fair, 70 to 79; poor, less than 70. †A, normal; B, nearly normal; C, abnormal; D, severely abnormal. ‡A, not improved; B, slightly improved; C, moderately improved; D, much improved.
CRYOPRESERVED MENISCUS ALLOGRAFT TABLE 6.
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Preoperative and Postoperative Lysholm Scores for Medial and Lateral Allografts Based on Method of Allograft Fixation Lysholm Score Bone Plug (n ⫽ 6)
Soft-Tissue Suture (n ⫽ 13)
Combination Fixation* (n ⫽ 1)
Allograft
Preoperative
Postoperative
Preoperative
Postoperative
Preoperative
Postoperative
Medial (n ⫽ 12) Lateral (n ⫽ 8) Total (N ⫽ 20)
51 (46-59) 54 (40-78) 52 (40-78)
66 (62-75) 75 (59-92) 73 (59-92)
55 (28-77) 53 (23-77) 54 (23-77)
79 (63-94) 75 (51-100) 77 (51-100)
— 49 49
— 70 70
*Posterior horn bone plug fixation and anterior horn soft-tissue suture fixation.
TABLE 7.
Preoperative and Postoperative Pain Scores for Medial and Lateral Allografts Based on Method of Allograft Fixation Pain Score Bone Plug (n ⫽ 6)
Soft-Tissue (n ⫽ 13)
Combination Fixation* (n ⫽ 1)
Allograft
Preoperative
Postoperative
Preoperative
Postoperative
Preoperative
Postoperative
Medial (n ⫽ 12) Lateral (n ⫽ 8) Total (N ⫽ 20)
4.6 (4-5) 4.3 (4-5) 4.5 (4-5)
3.6 (2-6) 1.6 (1-2) 2.7 (1-6)
4.6 (3-7) 5 (3-6) 4.8 (3-7)
1.8 (0-4) 2.8 (1-4) 2.2 (0-4)
— 49 49
— 70 70
*Posterior horn bone plug fixation and anterior horn soft-tissue suture fixation.
TABLE 8.
Lysholm and Pain Scores for Subgroups Undergoing Concomitant Procedures Lysholm Score (Range)
Allograft Medial Medial Medial Medial Lateral Lateral Lateral Lateral
(n ⫽ 12) with HTO (n ⫽ 1) with ACL reconstruction (n ⫽ 9) isolated (n ⫽ 1) (n ⫽ 8) with HTO (n ⫽ 1) with ACL reconstruction (n ⫽ 1) isolated (n ⫽ 4)
Pain Score (Range)
Preoperative
Postoperative
Preoperative
Postoperative
53 (28-77) 71 53 (28-77) 46 53 (23-78) 29 23 65 (43-78)
75 (62-94) 81 76 (62-94) 75 75 (51-100) 62 51 82 (59-100)
4.8 (3-7) 3 4.7 (3-7) 7 4.8 (3-6) 6 6 4.5 (4-6)
2.4 (0-6) 0 2.4 (0-4) 4 2.4 (1-4) 3 4 2 (1-3)
Abbreviations: ACL, anterior cruciate ligament; HTO, high tibial osteotomy.
Purpose: We report the results of cryopreserved meniscus allograft transplantations with 10 or more years of follow-up. Methods: Fourteen medial and 8 lateral meniscus allografts were evaluated with a mean follow-up of 141 months (range, 115 to 167 months). The clinical outcome and failure rate was evaluated by use of a Lysholm score and modified pain score in 22 patients. The results of radiographic and magnetic resonance imaging (MRI) analysis were reported in 15 and 7 patients, respectively. Results: Overall, 25% of medial allografts and 50% of lateral allografts failed. The combined failure rate was 35%. There was a 90% improvement in Lysholm scores, as well as pain scores. There were no discernible Lysholm or pain score differences for both lateral and medial allografts. Furthermore, there was no discernible difference in both Lysholm and pain scores between bone plug and soft-tissue methods of graft fixation. Ten of fifteen allografts showed radiographic joint space narrowing, and twelve had progression of degenerative joint disease. On MRI, all grafts had moderate meniscus shrinkage and five had grade III signal intensities. Eighty-five percent of patients underwent subsequent procedures, 5 of whom required total allograft resection and 2 of whom required partial allograft resection. One allograft required repair. Conclusions: Although transplantation of cryopreserved allografts improved knee pain and function, the average knee function was fair at long-term follow-up. Fifty-five percent of allografts failed when failure criteria for second-look surgery, knee improvement surveys, and MRI were added to Lysholm and pain score failures. The protective benefits of meniscus allografts remain debatable, and inferences cannot be made from this study. Level of Evidence: Level IV, therapeutic case series. Key Words: Meniscus—Allograft—Transplantation—Knee—Outcome—Arthroscopy—Arthritis.
T
he meniscus plays a crucial role in the biomechanical homeostasis of the knee joint. It functions to provide shock absorption, load bearing, load transmission, lubrication, and joint congruency. Me-
From the Orthopaedic Institute at Mercy Hospital (J.P.H.), Miami, Florida; and San Fernando Valley MRI (G.R.A.) and Southern California Orthopaedic Institute (W.D.P.), Van Nuys, California, U.S.A. The authors report no conflict of interest. Address correspondence and reprint requests to Jan Pieter Hommen, M.D., Orthopaedic Institute at Mercy Hospital, Suite 4008, 3659 S Miami Ave, Miami, FL 33133, U.S.A. E-mail: [email protected] © 2007 by the Arthroscopy Association of North America 0749-8063/07/2304-5325$32.00/0 doi:10.1016/j.arthro.2006.11.032 NOTE: To access the supplementary tables accompanying this report, visit the April issue of Arthroscopy at www. arthroscopyjournal.org.
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niscal procedures comprise more than 50% of the 1.5 million knee arthroscopies performed each year.1 Over the past 30 years, numerous studies have shown the increased risk of tibiofemoral arthrosis after meniscectomy. This has led to an increased emphasis on meniscus preservation techniques. Not all meniscus tears, however, are amenable to limited resection or repair, leaving the surgeon with few options, especially for the younger patient. When the meniscus is completely lost, transplantation of a meniscus allograft has been a therapeutic option with favorable improvements in knee pain and functionality. Meniscus transplants presumably increase the joint contact area, thereby lowering the joint contact peak stress. Allograft transplantation remains an evolving area and lacks general consensus regarding indications, tissue processing, secondary sterilization, surgical technique, and long-term function and efficacy.2-5 The long-term effects of meniscus allografts are difficult to
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 23, No 4 (April), 2007: pp 388-393
CRYOPRESERVED MENISCUS ALLOGRAFT interpret because of the paucity of long-term studies and the lack of standardized graft processing and implantation techniques. There are many studies with follow-up ranges exceeding 5 years3,4,6-8 and several reports with ranges of more than 10 years4,9,10; however, most of these studies are limited by mean follow-up lengths of less than 1 year4,11 or less than 5 years.3,4,6,7,9,10 Wirth et al.12 reported the only study to date with a mean follow-up of 10 or more years (14 years); however, they used lyophilized and deep-frozen meniscus allografts. When considering only cryopreserved allograft studies, the study with the longest follow-up was performed by van Arkel and de Boer,13 with a mean follow-up of 5 years (range, 4 to 126 months). The purpose of our study was to determine the long-term follow-up results (ⱖ10 years) of 22 consecutive, cryopreserved meniscus allografts.
METHODS Patients Between 1991 and 1995, the senior surgeon transplanted 22 sequential meniscus allografts in 22 patients. The mean age and median age of the patients at the time of transplantation were 32 years and 31 years, respectively, with a range of 17 to 46 years. One meniscus allograft was lost to follow-up, and one patient refused to participate in the study. The remaining 20 patients (20 allografts) had a mean duration of follow-up of 141 months (SD, 17.1 months), with a range of 115 to 167 months (Table 1, online only, available at www.arthroscopyjournal.org). Seven patients were unable to return for follow-up and were assessed by their local orthopaedic surgeon. Fourteen medial and eight lateral allografts were transplanted into thirteen men and nine women. Before the meniscus allograft procedure, the patients underwent a combined 47 operations. The indications for meniscus transplantation were prior meniscectomy, age less than 50 years, moderate to severe tibiofemoral pain, mild to advanced arthrosis, and 2 mm of tibiofemoral joint space or greater on 45° weight-bearing posteroanterior radiographs. Patients with surgically correctable malalignment or ligament instability were also candidates. Exclusion criteria included a history of knee infection, advanced arthrosis with flattening of the femoral condyle, concavity of the tibial plateau, malalignment, arthrofibrosis, and osteophytes that prevented anatomic seating of the meniscus allograft.3
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Subjective and Functional Evaluation In addition to a detailed physical examination, patients completed a Lysholm knee score and a modified pain score before surgery. Postoperative evaluation was performed by use of Lysholm, Tegner, and International Knee Documentation Committee (IKDC 2000) scores, as well as Short Form 12 (SF-12) and modified pain scores. Furthermore, patients were asked to complete a knee survey rating the improvement of the knee. Arthroscopic Classification Arthroscopic assessment of the articular cartilage was performed at the time of transplantation and classified according to the Outerbridge grading system. Radiographic Evaluation Preoperative and postoperative lower limb tibiofemoral joint spaces were evaluated via standing bilateral posteroanterior 45° views by a single observer. Similarly, the Fairbank arthrosis classification was determined for the preoperative and postoperative radiographs. Fifteen patients had postoperative radiographs available for measurement. Magnetic Resonance Imaging Studies Seven allografts underwent magnetic resonance imaging (MRI) without arthrography. The affected tibiofemoral compartment was categorized via qualitative analysis as having no, mild, moderate, or severe arthrosis. The meniscal signal changes were classified as normal, grade 1, grade 2, or grade 3. Allograft size reduction was graded as mild, moderate, or severe. Cumulative Meniscus Failures Patients who had a poor Lysholm score (⬍65) or who had no improvement in the pain score were considered failures. In a separate assessment, these pa1 tients were combined with surgical failures (requiring ⬎2 allograft meniscectomy), MRI failures (grade III signal), and patients reporting no improvement in subjective knee survey scores. Surgical Technique All patients underwent transplantation with cryopreserved meniscus allografts procured by CryoLife Orthopaedics (Marietta, GA). Allografts were sized by use of standing anteroposterior and lateral radiographs allowing for magnification. All knees underwent arthroscopic assessment to determine the status of the
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meniscus, ligaments, and cartilage. In those knees for which transplantation was indicated, the meniscus was resected, leaving a bleeding peripheral rim. The grafts were introduced through a medial or lateral parapatellar arthrotomy. When needed, the medial epicondyle underwent osteotomy and was later restored with a screw or staple fixation. Of the 12 medial menisci, 3 were secured via a double bone plug technique2 and 8 were secured via an all-suture technique.10 One medial meniscus was implanted via a posterior bone plug and anterior suture fixation because of improper seating of the anterior bone plug. Two of the eight lateral menisci were secured via a single bone plug technique by use of a trough,2 and five were placed via an all-suture technique. One lateral meniscus was implanted via a double bone plug technique. A posteromedial or posterolateral corner counter-incision was used to assist in retrieving and suturing the meniscus via an arthroscopic inside-out suture technique with vertical polydioxanone surgical sutures (PDS II; Ethicon, Somerville, NJ). A Meniscus Arrow (Linvatec, Largo, FL) was used in one allograft to secure the allograft to the meniscus rim. In 15 patients, 24 concomitant procedures were performed (Table 2, online only, available at www.arthroscopyjournal.org). Statistical Analysis Statistical analysis was performed by use of 2, analysis of variance, Fisher exact, paired t, and MannWhitney tests as indicated for the data. P ⬍ .05 was considered statistically significant. RESULTS Clinical Outcome There was a significant improvement in the overall mean Lysholm score, from 53 (range, 23 to 78) preoperatively to 75 (range, 51 to 100) postoperatively (P ⬍ .001) (Table 3, online only, available at www. arthroscopyjournal.org). The postoperative scores had improved in 18 (90%) of the 20 allografts, with 1 excellent, 5 good, 8 fair, and 6 poor scores. Those patients with worsened scores had lateral allografts, being split evenly between those with bone plug fixation and those with soft-tissue fixation. The 6 poor postoperative Lysholm scores (⬍65) were distributed evenly between the lateral and medial allografts (Table 4, online only, available at www.arthroscopyjournal.org). Patients with poor postoperative Lysholm scores had correspondingly lower preoperative Lysholm scores compared with the
other patients (42 and 57, respectively; P ⫽ .0259). However, both groups had significant improvements in postoperative scores (60 [P ⫽ .0133] and 82 [P ⬍ .0003], respectively). The mean pain score improved from 4.8 (range, 3 to 7) preoperatively to 2.4 (range, 0 to 6) postoperatively (P ⬍ .001) (Table 3, online only, available at www.arthroscopyjournal.org). The pain scores improved in 18 of 20 allografts (90%). One medial allograft, with bone plug fixation, had a worse postoperative pain score, and one lateral allograft, with soft-tissue fixation, had no change in pain score. The postoperative IKDC, Tegner, SF-12, and subjective scores are shown in Table 5 (online only, available at www.arthroscopyjournal.org). Thirteen patients reported that the knee was much improved, one was moderately improved, two were slightly improved, and four had no improvement (Table 5, online only, available at www.arthroscopyjournal.org). There was no significant difference between the lateral and medial allografts in terms of postoperative Lysholm and pain scores (Table 3, online only, available at www.arthroscopyjournal.org). The bone plug and soft-tissue fixation methods yielded similar postoperative Lysholm results (73 and 77, respectively; P ⫽ .3228) (Table 6, online only, available at www.arthroscopyjournal.org). Likewise, the 2 methods yielded similar postoperative pain scores (2.7 and 2.2, respectively; P ⫽ .7653) (Table 7, online only, available at www.arthroscopyjournal. org). Only 1 patient, who had poor Lysholm and IKDC scores, would not undergo this procedure again and would also not recommend this procedure to others. A combined 24 concomitant procedures were performed in 15 patients. Patients with higher Outerbridge cartilage injury scores tended to have an increased number of concomitant procedures. The mean Lysholm and pain scores were improved for the subgroups of concomitant procedures, although it was difficult to draw conclusions from these data because of the small study sample size (Table 8, online only, available at www.arthroscopyjournal.org). There was a trend toward smaller Lysholm score improvements in those patients with 3 additional procedures than in those with no additional procedures. Workers’ Compensation patients had similar significant improvements in mean Lysholm scores (54 to 76, P ⫽ .0044) and pain scores (4.5 to 2.1, P ⫽ .0049) postoperatively relative to non–Workers’ Compensation patients (52 to 76 [P ⫽ .0024] and 4.9 to 2.6 [P ⫽ .0001], respectively).
CRYOPRESERVED MENISCUS ALLOGRAFT Arthroscopic Classification According to the Outerbridge classification, the cartilage score for the affected compartment at the time of allograft surgery was grade 0 in 4 patients, grade 1 in 0, grade 2 in 6, grade 3 in 8, and grade 4 in 2. Although a lower Outerbridge score trended toward a better postoperative Lysholm score, drawing conclusions based on these data was difficult because of the sample size. Radiographic Findings Of the 15 patients with follow-up radiographs, 10 had narrowing of the involved tibiofemoral compartment (mean, 5.15 ⫾ 1.0 mm preoperatively and 4 ⫾ 1.1 mm postoperatively; P ⫽ .0002). Those with narrowing tended to have lower mean postoperative Lysholm scores (72 v 92). Twelve patients had a progression of the Fairbank degenerative joint disease score in the transplanted compartment from 0.5 ⫾ 0.6 to 1.3 ⫾ 0.9 (P ⫽ .0001). These patients appeared to have a lower postoperative Lysholm score (74 v 81 in patients without progression, P ⫽ .2994).
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allograft, which originally had suture fixation of the anterior and posterior horns and Meniscus Arrow (Linvatec) fixation of the peripheral rim, required subsequent meniscus repair at 5 years for a peripheral rim detachment. No other patient in this study had Meniscus Arrow peripheral rim fixation. Two partial menis1 cectomies (⬍2 of meniscus) and 5 total meniscecto1 mies (⬎2 of meniscus) were performed. Cumulative Meniscus Failures By use of a Lysholm score of less than 65 and no improvement in pain score as clinical criteria for failure, there were 7 allograft failures (35%). Failure occurred in 3 of 12 medial allografts (25%) and 4 of 8 lateral allografts (50%) (Table 5, online only, available at www.arthroscopyjournal.org). If we combine these results with failures from second-look surgery (5 total surgical failures) and MRI studies (5 allografts with grade III tears), as well as patients with reports of no improvement on the knee survey (4 allografts), the 10-year survival rate is 45% (9 of 20), with failures in 58% of medial allografts (7 of 12) and 50% of lateral allografts (4/8).
MRI Findings Of the 7 patients who underwent MRI, 5 had a grade III tear of the posterior horn of the allograft. All 5 patients had corresponding joint line tenderness and a McMurray sign. One underwent subsequent total meniscectomy. Of the allografts, 4 had moderately truncated mid zones and 2 had moderately diminutive anterior horns. One allograft had a severely truncated mid zone. The cartilage classification was normal in 1, mild in 2, moderate in 3, and severe in 1. Postoperative mean Lysholm scores relative to the corresponding 4 grades were as follows: 70, 81, 75, and 57, respectively. Interpretation of these data was limited because of the small sample size. Subsequent Knee Surgeries A total of 40 subsequent surgical procedures were performed in 17 patients. Other than those requiring additional meniscus work, there were 17 complications. Eleven allografts developed postoperative arthrofibrosis requiring arthroscopic synovectomy and manipulation under anesthesia. Medial epicondylectomy did not correlate with the development of arthrofibrosis (P ⫽ .37). Two patients underwent removal for painful, prominent anterior cruciate ligament tibial hardware. In one patient, scar revision was required and developed complex regional pain syndrome. One
DISCUSSION Historically, the first meniscus replacement surgery dates back to 1916, when Lexer performed autogenous fat tissue interposition arthroplasty.4 The first free-meniscus transplantations were reported by Milachowski and Wirth in 1984.12 Since then, numerous studies and reviews have been reported related to meniscus transplantation. Data from 2002 suggested that more than 4,000 meniscus transplants had been performed since 1991, with more than 800 transplants performed per year. Meniscus allograft surgery remains an evolving area with considerable debate as to proper tissue processing, implantation, indications, and potential long-term outcome. The methods of tissue processing and preservation have impacted meniscus allograft survival. Several excellent reviews have discussed the merits and drawbacks of each method.1,2,4,5 The differences in meniscus preservation techniques have made comparison between studies difficult. Recent studies have shown that the survival rate for cryopreserved meniscus allografts is approximately 70%. The longest follow-up for cryopreserved menisci has been reported by van Arkel and de Boer,13 with a mean of 5 years and a range of 0.3 to 10.5 years. They reported cumulative survival rates for lateral, medial, and combined allo-
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grafts of 76%, 50%, and 67%, respectively. Graft failure criteria were persistent pain, an unsuccessful Knee Assessment Scoring System result, a poor Lysholm score, and a detached or torn allograft at second-look arthroscopy. Lateral grafts failed on average 53 months after implantation, whereas medial allografts failed at a mean of 25 months. Using Lysholm and pain score criteria for failure, our study showed a similar total survival rate of 65%, with survival rates of 50% for lateral allografts and 75% for medial allografts. If we apply failure criteria similar to those used in the study of van Arkel and de Boer13 (no improvement in pain score, poor Lysholm score, and surgical second-look failures), our study shows a 60% combined survival rate (50% lateral and 66% medial). We further attempted to show the total meniscus failure rate by combining our initial study failure criteria with known surgical failures, unimproved patient knee survey scores, and MRI failures and found a total survival rate of 45% (42% medial and 50% lateral). Our MRI data, though limited by the number of follow-up scans, seem to correlate with previous studies linking clinical and MRI results.5,6,13 In our study, patients with grade III allograft signals also had mechanical symptoms in the operative compartment. Because IKDC, Tegner, and SF-12 scores were not assessed preoperatively, they were not included. The ideal method for meniscus fixation remains a topic of debate. A review of the literature reveals no real discernible clinical difference between the bone plug and soft-tissue fixation methods.4 Cadaveric studies in human beings have shown that a secure, anatomic fixation with bone plugs attached to the anterior and posterior horn is essential to restore normal contact mechanics for both the medial and lateral menisci.4 The advantages of soft-tissue fixation include ease with sizing, anatomic positioning, and securing of the graft. The importance of anatomic placement of bone plugs and the adverse effect of nonanatomic placement on contact pressure patterns have been shown in cadaveric knees.4 Our study revealed no differences between fixation methods used; however, our sample size was limited, and a variety of implantation techniques were used. Whether meniscus grafts can delay or prevent the progression of degenerative changes and joint space narrowing also remains unclear.4,5,10 A significant number of knees in our study had a progression of compartment narrowing and degenerative joint disease. Garrett and Stevensen14 reported no significant decrease in joint space at 24 to 44 months’ follow-up.
However, studies with longer follow-up have shown radiographic progression. Rath et al.7 reported that the compartment space of 11 knees averaged 5.2 mm before surgery and 4.5 mm at 2 to 8 years’ follow-up. One patient lost more than 1 mm of joint space. Wirth et al.,12 with a mean follow-up of 14 years, showed evidence of degenerative changes on all 11 available radiographs. At 13 to 69 months of follow-up, Stollsteimer et al.15 found a mean of 1.7 mm of joint space narrowing in 10 of 22 patients. Ryu et al.,8 in a study with a minimum follow-up of 2 years, found joint space narrowing of 1 to 4 mm in 3 patients and no changes in 5 patients. Carter16 found evidence of progression in only 2 of 46 knees at a mean of 34.5 months. In studies in rabbits, Rijk5 concluded that meniscus grafts were unable to prevent the progression of arthritis after 1 year. Because radiographic follow-up was limited in our study, we are cautious in interpreting these results. This study has several limitations, including the lack of a prospective and randomized design with a control group. This study implemented several surgical techniques, reflecting the lack of a clear consensus for optimal graft fixation. Furthermore, meniscus allografts were implanted in knees with a variety of degenerative knee scores. Two patients with grade IV changes underwent the procedure in 1992, whereas eight with grade III changes underwent implantation between 1991 and 1995. Literature reports of poor outcomes in the setting of advanced degenerative arthrosis began to emerge in the mid 1990s.2,4,6,11 Inferences concerning the cartilage-protective effects and survivorship of the allografts should be made with caution. The purpose of this study is to report the long-term outcomes of 22 consecutive meniscus allograft transplantations, performed by a single surgeon, to treat a difficult problem in a young patient population with limited treatment alternatives.
CONCLUSIONS At 10-year follow-up, cryopreserved meniscus allografts improved knee pain and function; however, the average knee function was fair. Forty-five percent of allografts survived when failure criteria for secondlook surgery, knee improvement surveys, and MRI were added to Lysholm and pain score failures. The long-term chondral protective benefits of meniscus allografts remain debatable and cannot be inferred from this study.
CRYOPRESERVED MENISCUS ALLOGRAFT Acknowledgment: The authors acknowledge Richard D. Ferkel, M.D., Marc J. Friedman, M.D., and Loren Khoury for their assistance on this project.
8. 9.
REFERENCES 10. 1. Peters G, Wirth CJ. The current state of meniscal allograft transplantation and replacement. Knee 2003;10:19-31. 2. Cole BJ, Carter TR, Rodeo SA. Allograft meniscal transplantation: Background, techniques, and results. Instr Course Lect 2003;52:383-396. 3. Noyes FR, Barber-Westin SD, Rankin M. Meniscus transplantation in symptomatic patients less than fifty years old. J Bone Joint Surg Am 2004;86:1392-1404. 4. Rijk PC. Meniscal allograft transplantation—Part I: Background, results, graft selection and preservation, and surgical considerations. Arthroscopy 2004;20:728-743. 5. Rijk PC. Meniscal allograft transplantation—Part II: Alternative treatments, effects on articular cartilage, and future directions. Arthroscopy 2004;20:851-859. 6. Noyes FR, Barber-Westin SD. Irradiated meniscus allografts in the human knee: A two to five year follow up study. Orthop Trans 1995;19:417. 7. Rath E, Richmond JC, Yassir W, Albright JD, Gundogan F.
11. 12. 13. 14. 15. 16.
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Meniscal allograft transplantation. Two- to eight-year results. Am J Sports Med 2001;29:410-414. Ryu RK, Dunbar VWH, Morse GG. Meniscus allograft replacement: A 1-year to 6-year experience. Arthroscopy 2002; 18:989-994. Milachowski KA, Weismeier K, Wirth CJ. Homologous meniscus transplantation. Experimental and clinical results. Int Orthop 1989;13:1-11. 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. Veltri DM, Warren RF, Wickiewicz TL, O’Brien SJ. Current status of allograft meniscal transplantation. Clin Orthop Relat Res 1994:44-55. 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. van Arkel ER, de Boer HH. Survival analysis of human meniscal transplantations. J Bone Joint Surg Br 2002;84:227-231. Garrett JC, Stevensen RN. Meniscal transplantation in the human knee: A preliminary report. Arthroscopy 1991;7:57-62. Stollsteimer GT, Shelton WR, Dukes A, Bomboy AL. Meniscal allograft transplantation: A 1- to 5-year follow-up of 22 patients. Arthroscopy 2000;16:343-347. Carter TR. Meniscal allograft transplantation. Sports Med Arthrosc Rev 1999;7:51-62.
CRYOPRESERVED MENISCUS ALLOGRAFT TABLE 1.
Allograft
No.
M
F
Mean Age (yr) (Range)
Lateral Medial Total
8 12 20
4 9 13
4 3 7
35 (28-43) 30 (17-41) 32 (17-43)
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Meniscus Allograft Details
Bone Plug Fixation
Soft-Tissue Suture Fixation
Combination Fixation*
Mean Follow-up (mo) (Range)
Mean Outerbridge Classification (Range)†
3 3 6
5 8 13
0 1 1
131 (113-157) 146 (120-167) 140 (114-167)
2.25 (2-3) 2.15 (0-4) 2.2 (0-4)
Mean Preoperative Fairbank Classification (Range)‡ 0.75 (0-2) 0.25 (0-1) 0.45 (0-2)
*Posterior horn bone plug fixation and anterior horn soft-tissue suture fixation. †Outerbridge classification determined arthroscopically at the time of graft transplantation, where 0 indicates normal cartilage, 1 indicates cartilage with softening and swelling, 2 indicates a partial-thickness defect with fissures on the surface that do not reach subchondral bone or exceed 1.5 cm in diameter, 3 indicates fissuring to the level of subchondral bone in an area with a diameter of more than 1.5 cm, and 4 indicates exposed subchondral bone. ‡Radiographic Fairbank classification, where 0 indicates normal, 1 indicates mild, 2 indicates moderate, and 3 indicates severe.
TABLE 2.
Allograft
ACL Reconstruction
Revision ACL Reconstruction
Medial Lateral Total
8 1 9
1 0 1
Concomitant Procedures
HTO
Lateral Retinaculum Release
Lysis of Adhesions
Loose Body Removal
Capsular Plication
Chondroplasty of Femoral Condyle
Total
1 1 2
3 0 3
1 2 3
1 0 1
2 0 2
2 1 3
19 5 24
Abbreviations: ACL, anterior cruciate ligament; HTO, high tibial osteotomy.
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J. P. HOMMEN ET AL. TABLE 3.
Outcome Measures
Lysholm Score* (Range)
Pain Score† (Range)
Allograft
Preoperative
Postoperative
Preoperative
Postoperative
Lateral (n ⫽ 8) Medial (n ⫽ 12) Total (N ⫽ 20)
53 (23-78) 53 (28-77) 53 (23-78)
75 (51-100) 75 (62-94) 75 (51-100)
4.8 (3-6) 4.8 (3-7) 4.8 (3-7)
2.4 (1-4) 2.4 (0-6) 2.4 (0-6)
*A score of greater than 94 is excellent; 84 to 94, good; 65 to 83, fair; and less than 65, poor. †Ranging from 0 to 10 (where 0 indicates no pain and 10 indicates severe pain).
TABLE 4.
Meniscus Allografts With Poor Postoperative Scores
Surgical Subjective Mean Time Objective Failure Knee MRI to Total IKDC Subjective (n ⫽ 8)† Status Grade Surgical Score IKDC Lysholm Score: Not Combined III Failure (mo) (C or D) Score Score Signal Improved Failures‡ (range) (n ⫽ 13)* Total Partial (⬍70) (⬍65) Same Worsened Pain Score Versus Preoperative
Allograft Lateral (n ⫽ 8) Medial (n ⫽ 12) Total (N ⫽ 20)
3 3 6
1 0 1
0 1 1
2 4 6
5 3 8
3 2 5
3 0 3
65 (3-120) 78 (72-84) 70 (3-120)
1 4 5
1 3 4
4 (50%) 3 (25%) 7 (35%)
*In 13 patients, postoperative objective IKDC scores were available. †Eight patients underwent subsequent surgery for allograft pathology, where partial failure indicates that subsequent repair or partial meniscectomy (⬍1/2 of meniscus) was required and total failure indicates that subsequent meniscectomy (⬎1/2 meniscus) was required. ‡Combined failures include those patients with a Lysholm score of less than 65 and an unimproved or worsened pain score.
TABLE 5.
Postoperative Scores for Meniscus Allografts
Objective IKDC Score† (n ⫽ 13)
Allograft
Subjective IKDC Score* (N ⫽ 20) (Range)
A
B
C
Lateral (n ⫽ 8) Medial (n ⫽ 12) Total (N ⫽ 20)
77 (66-95) 77 (63-95) 77 (63-95)
1 1 2
1 2 3
5 3 8
SF-12 Score (N ⫽ 20) (Range)
Subjective Score‡ (N ⫽ 20)
D
Tegner Score (N ⫽ 20) (Range)
PCS
MCS
A
B
C
D
0 0 0
4.6 (2-9) 4.3 (1-6) 4.5 (1-9)
51 (43-57) 52 (43-56) 52 (43-57)
62 (51-66) 62 (57-66) 62 (52-66)
1 3 4
1 1 2
1 0 1
5 8 13
Abbreviations: PCS, physical comprehensive score; MCS, mental comprehensive score. *Excellent, 90 or greater; good, 80 to 89; fair, 70 to 79; poor, less than 70. †A, normal; B, nearly normal; C, abnormal; D, severely abnormal. ‡A, not improved; B, slightly improved; C, moderately improved; D, much improved.
CRYOPRESERVED MENISCUS ALLOGRAFT TABLE 6.
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Preoperative and Postoperative Lysholm Scores for Medial and Lateral Allografts Based on Method of Allograft Fixation Lysholm Score Bone Plug (n ⫽ 6)
Soft-Tissue Suture (n ⫽ 13)
Combination Fixation* (n ⫽ 1)
Allograft
Preoperative
Postoperative
Preoperative
Postoperative
Preoperative
Postoperative
Medial (n ⫽ 12) Lateral (n ⫽ 8) Total (N ⫽ 20)
51 (46-59) 54 (40-78) 52 (40-78)
66 (62-75) 75 (59-92) 73 (59-92)
55 (28-77) 53 (23-77) 54 (23-77)
79 (63-94) 75 (51-100) 77 (51-100)
— 49 49
— 70 70
*Posterior horn bone plug fixation and anterior horn soft-tissue suture fixation.
TABLE 7.
Preoperative and Postoperative Pain Scores for Medial and Lateral Allografts Based on Method of Allograft Fixation Pain Score Bone Plug (n ⫽ 6)
Soft-Tissue (n ⫽ 13)
Combination Fixation* (n ⫽ 1)
Allograft
Preoperative
Postoperative
Preoperative
Postoperative
Preoperative
Postoperative
Medial (n ⫽ 12) Lateral (n ⫽ 8) Total (N ⫽ 20)
4.6 (4-5) 4.3 (4-5) 4.5 (4-5)
3.6 (2-6) 1.6 (1-2) 2.7 (1-6)
4.6 (3-7) 5 (3-6) 4.8 (3-7)
1.8 (0-4) 2.8 (1-4) 2.2 (0-4)
— 49 49
— 70 70
*Posterior horn bone plug fixation and anterior horn soft-tissue suture fixation.
TABLE 8.
Lysholm and Pain Scores for Subgroups Undergoing Concomitant Procedures Lysholm Score (Range)
Allograft Medial Medial Medial Medial Lateral Lateral Lateral Lateral
(n ⫽ 12) with HTO (n ⫽ 1) with ACL reconstruction (n ⫽ 9) isolated (n ⫽ 1) (n ⫽ 8) with HTO (n ⫽ 1) with ACL reconstruction (n ⫽ 1) isolated (n ⫽ 4)
Pain Score (Range)
Preoperative
Postoperative
Preoperative
Postoperative
53 (28-77) 71 53 (28-77) 46 53 (23-78) 29 23 65 (43-78)
75 (62-94) 81 76 (62-94) 75 75 (51-100) 62 51 82 (59-100)
4.8 (3-7) 3 4.7 (3-7) 7 4.8 (3-6) 6 6 4.5 (4-6)
2.4 (0-6) 0 2.4 (0-4) 4 2.4 (1-4) 3 4 2 (1-3)
Abbreviations: ACL, anterior cruciate ligament; HTO, high tibial osteotomy.