| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Sign In to gain access to subscriptions and/or personal tools.
|
|
|
|||||||
Sign In to gain access to subscriptions and/or personal tools. |
|||||||||
Letter to the Editor |
Cincinnati, Ohio
Dear Editor:
We read with interest the article by Cole et al, "Prospective Evaluation of Allograft Meniscus Transplantation: A Minimum 2-Year Follow-up" (June 2006, pp 919–927). This study presented the subjective and functional early (2- to 4.8-year) follow-up results of 44 meniscus allografts. The authors excluded patients with severe arthritic degeneration but included those who had concomitant procedures for chondral defects, which represented 47.5% of the study group. The results led the authors to conclude that "symptomatic patients with appropriate indications should expect to do well with respect to pain relief and an ability to increase activity levels after transplantation."
In the Discussion section, the authors cited many other meniscus allograft investigations of short follow-up duration, all with high success rates in terms of subjective and functional criteria. However, the authors failed to cite many other studies that demonstrated different findings, especially when magnetic resonance imaging (MRI) was used to provide a more objective analysis of allograft size and position in the joint.1,2,4,6,7 The concern we have is that the authors presented 1 potentially biased view of this operation, without balancing the favorable short-term results to those raised by other investigators with respect to MRI findings and survivorship rates.
For instance, Stollsteimer et al4 reported on 23 patients who received meniscal allografts and were followed from 13 to 69 months postoperatively. Eight patients (35%) required a second operation for meniscal symptoms. Although good pain relief was obtained in 18 knees, MRI data from 12 knees showed that shrinkage of the transplants had occurred, as the allografts were reported to be an average of 63% the size of the contralateral normal menisci.
Rath et al3 followed 22 meniscal allografts 2 to 8 years postoperatively. Even though all patients except 1 had significant improvements in SF-36 scores, 8 menisci (36%) failed and were removed an average of 2.5 years postimplantation.
Van Arkel et al6 reported on 19 cryopreserved meniscus allografts followed 14 to 55 months postoperatively with MRI, arthroscopy, and clinical examination. Based on clinical findings alone, 16 allografts were successful and 3 failed. However, MRI identified 8 of the 19 cases as failures because 7 allografts had severe or moderate shrinkage. None of the allografts were in a normal position; 11 showed subextrusion, 6 demonstrated extrusion, and 2 had bucket handle–like appearances.
Van Arkel and de Boer5 presented a survival analysis of 63 consecutive meniscal allografts followed 4 to 126 months postoperatively. Persistent pain or mechanical damage (detached or torn allograft) was used to document allograft failure. The cumulative survival rates of lateral, medial, and combined allografts in the same knee were 76%, 50%, and 67%, respectively.
We recently reported the results of 40 consecutive meniscus allografts followed 2 to 5.7 years postoperatively.1 Patients with advanced knee joint arthrosis were excluded from the procedure. Meniscus allograft characteristics were determined by a critical rating system that combined subjective, clinical, and MRI factors. An osteochondral autograft transfer was also done in 16 knees. The subjective and functional results appeared reasonable because 34 of the 38 patients (89%) rated their knee condition as improved. Before surgery, 30 patients (79%) had pain with daily activities, but at follow-up, only 4 (11%) had such pain. However, when MRI data were added to the rating, the meniscus allograft characteristics were found to be normal in 17 (42.5%), altered in 12 (30%), and failed in 11 (27.5%).
Potter et al2 followed 29 fresh meniscal allografts with MRI and clinical examination 3 to 41 months postoperatively. Increased signal intensity was detected in the posterior horn in 15 knees, and peripheral displacement at the body was noted in 11 knees; all of these knees had moderate or severe chondral degeneration. Knees with mild degeneration had no abnormalities noted in the meniscus allografts and had superior clinical results compared with those with severe degeneration. These results were quite similar to those we previously reported in a group of 96 fresh-frozen irradiated allografts, which Cole et al cited in their article. In that investigation, the meniscus transplant failure rate ranged from 6% (1 of 18 knees) in knees with normal or only mild arthrosis on MRI to 80% (12 of 15 knees) in knees with advanced arthrosis. We believe that neither the irradiation of the graft nor fixation caused the failures in this study. The investigations cited above all used allografts that either had been cryopreserved, had been frozen, or were fresh at the time of implantation. The high failure rates show a lack of correlation or strong evidence that the irradiation process alone was the cause of the failures in our study. In addition, the knee joint remodeling that occurred in the knees with advanced arthrosis (narrowing of the joint space, flattening of the femoral condyle, increased concavity of the tibial plateau, and development of marginal osteophytes) had the potential to exert undue contact pressure on the meniscus allograft. We noted that Cole et al excluded patients with these advanced degenerative changes from their study, and we wondered if this decision was because of the data cited above from multiple centers demonstrating the potential high failure rates of meniscus allografts in knees with advanced arthrosis.
We also wondered in the authors’ series how many patients did not have pain relief with daily activities or on tibiofemoral compression testing at follow-up. Because the subjective and functional scaled data were only presented as mean values, one cannot determine how many knees were clinically improved by the operation. For instance, in the Noyes symptom rating, we wondered what the distribution was of patients in the various categories for pain before and after surgery (moderate–severe with activities of daily living, none with activities of daily living, none with light sports activities, none with moderate sports activities, none with strenuous sports activities). If the authors calculated this factor by summing the scores for pain, swelling, partial giving-way, and full giving-way, we wonder if the mean value could have been inflated given that only 6 knees required a ligament reconstruction and most would therefore have scored highly on the 2 giving-way scales.
Second, the mean IKDC score was 64.1 ± 20 points at follow-up. Although this represented a statistically significant improvement over the preoperative score, it still indicates that many knees had problems, which needs clarification, because the IKDC maximum score is 100 points. Third, the overall condition of the knee would be another factor in which further data would be helpful, such as the distribution of patients in the various categories and how many patients improved by at least 2 points on the 0- to 10-point scale. Fourth, the Noyes sports activity data should be presented in distribution form, allowing an indication of exactly what types of athletics patients returned to at follow-up and whether any patients were participating with symptoms.
We hope that, in the future, MRI will become mandatory in studies that report the clinical assessment of meniscus allografts. We respect and agree with the authors’ conclusion that longer term studies are required to determine the ability of these transplants to provide a chondroprotective effect to the meniscectomized tibiofemoral compartment. In our opinion, the long-term prognosis for this operation remains guarded and inconclusive and is most indicated in young symptomatic patients postmeniscectomy in whom there are no other options available.
REFERENCES
Chicago, Illinois
I read the letter to the editor from Dr Noyes and Sue Barber-Westin pertaining to our recently published article. Their first point addresses the absence of studies cited related to outcomes as evaluated by MRI. We routinely obtain MRIs on our patients postoperatively, and similar to the papers cited, we have found some potentially disturbing findings (shrinkage, extrusion, fluid signal within the substance of the meniscus) that, although alarming, have not correlated with our clinical outcomes. We believe that these findings might attest to the potential for midterm degeneration but, as of yet, have not found that to be the case for patients reaching the 5-year follow-up time point. Interestingly, shrinkage has not been a consistent finding at second-look arthroscopy in those who have required additional treatment following index allograft meniscus transplantation. We do, however, caution our patients that allograft meniscus transplantation is not a procedure that categorically prevents articular cartilage degeneration or the ultimate need for knee replacement surgery. We advise our patients that good and excellent results following meniscus transplantation, with or without concomitant procedures, are based solely on patients reporting reductions in pain and improvements in activity levels. I firmly believe that the best case scenario is that allograft meniscus transplantation is a "bridging procedure" for patients and should not be considered a definitive treatment option that eliminates the chances for recurrent symptoms or further degeneration. That being said, if it can allow a patient to become more age appropriate for arthroplasty, I still consider this as an effective treatment option for this difficult patient group, at least in the short and intermediate term.
An additional point that their letter made is our presentation of mean scores including the IKDC scores and the fact that we did not present the actual number of patients without symptom relief during activities of daily living or during tibiofemoral compression testing, specifically, referencing patients undergoing concomitant ACL reconstruction (n = 6). Notably, all of these patients complained of pain and instability preoperatively that were substantially reduced at follow-up. We agree that breaking out a single variable related to how many patients had complete pain relief with activities of daily living would be interesting, and we will present that data in our midterm follow-up study. Our summary findings are that very few patients became completely pain free, but the vast majority had profound reductions in symptoms.
The signs of discomfort during tibiofemoral compression testing including provocative testing in my hands have been exceptionally nonspecific. Although we have that data from our physical examination findings in the IKDC data set, as a preoperative score and follow-up sign, they were not found to be reproducible or consistent with what patients actually complained of when activities were limited. Thus, we question the value of that data as a primary or secondary outcome finding.
Regarding overall knee function, the so-called "Modified Cincinnati Score," which is really a hybrid score derived from Dr Noyes’ and his collaborators’ work, we also will be presenting that data in greater detail including an overall distribution with activity data as recommended for our midterm follow-up. We have used the 0 to 10 scale for nearly 10 years and find it indispensable in educating our patients about what to expect following cartilage repair procedures in general.
In general, we chose to present our data for this study based on the methods used by several previous authors, yet we appreciate the recommendations for a more detailed analysis that might help the reader appreciate the nuances of the results following allograft meniscus transplantation. As to the value of including MRI as a primary outcome variable, we would argue that at least for our series of patients, the MRI findings have not correlated with clinical outcome. Yet, we agree that these findings may have some greater correlation at longer term follow-up and warrant further consideration.
Thank you for taking the time to evaluate our article.
This article has been cited by other articles:
|
|
 |
|
  L. J.-P. H. Rue, A. B. Yanke, M. L. Busam, A. G. McNickle, and B. J. Cole Prospective Evaluation of Concurrent Meniscus Transplantation and Articular Cartilage Repair: Minimum 2-Year Follow-Up Am. J. Sports Med., September 1, 2008; 36(9): 1770 - 1778. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
