Meniscal allograft transplantation: a meta-analysis

Abstract

Purpose: This meta-analysis evaluates the mid- to long-term survival outcome of MAT (meniscal allograft transplantation). Potential prognosticators, with particular focus on chondral status and age of the patient at the time of transplantation, were also analysed.

Study design: Meta-analysis.

Methods: An online database search was performed using following search string: "meniscal allograft transplantation" and "outcome". A total of 65 articles were analysed for a total of 3157 performed MAT with a mean follow-up of 5.4 years. Subjective and clinical data was analysed.

Results: The subjective and objective results of 2977 patients (3157 allografts) were analysed; 70% were male, 30% were female. Thirty-eight percent received an isolated MAT. All other patients underwent at least one concomitant procedure. Lysholm, Knee injury and Osteoarthritis Outcome (KOOS), International Knee Documentation Committee (IKDC) and Visual Analogue Scale (VAS) scores were analysed. All scores showed a good patient satisfaction at long-term follow-up. The mean overall survival rate was 80.9%. Complication rates were comparable to standard meniscal repair surgery. There was a degenerative evolution in osteoarthritis with at least one grade in 1760 radiographically analysed patients. Concomitant procedures seem to have no effect on the outcome. Age at transplantation is a negative prognosticator. The body mass index (BMI) of the patient shows a slightly negative correlation with the outcome of MAT.

Conclusions: MAT is a viable solution for the younger patient with chronic pain in the meniscectomised knee joint. The complications are not severe and comparable to meniscal repair. The overall failure rate at final follow-up is acceptable and the allograft heals well in most cases, but MAT cannot be seen as a definitive solution for post-meniscectomy pain. The correct approach to the chronic painful total meniscectomised knee joint thus requires consideration of all pathologies including alignment, stability, meniscal abnormality and cartilage degeneration. It requires possibly combined but appropriate action in that order.

Figure 1.

Prisma study flowchart.

Figure 2.

Overview of associated procedures. As shown only 38.8% of the patient population underwent isolated MAT. Most frequently an anterior cruciate ligament reconstruction was performed, followed by an osteotomy of the fibula or tibia. Other procedures performed were all done in attempt to optimize the chondral surface and the alignment of the knee.

Figure 3.

Gross profit in mean Lysholm score based on mean follow-up time. At short- to mid-term follow up an overall profit of at least 20 points in Lysholm score can be seen which means patients feel a significant improvement in their daily functioning. However later on they tend to have a lesser improvement as a decline in gross profit can be observed at a longer follow-up time.

Figure 4.

Gross profit in mean IKDC-score based on mean follow-up time. The gross profit in IKDC-score is on average 24 points. The biggest improvement in daily living can be observed in patients interviewed at short-to mid-term follow-up. A declining trend in the IKDC-score over time is also present.

Figure 5.

Gross loss in mean VAS pain-score based on mean follow-up time. Patients tend to have less pain after MAT as shown in Figure 4. On average the analysed articles reported a loss of pain of around 40 points on the VAS-scale at short- to mid-term follow-up. Articles reporting VAS-scores at longer follow-up times reported an increase in pain, thus their patients reported less loss of pain.

Figure 6.

Difference in mean pre-operative KOOS-scores and mean KOOS-scores at final follow-up. In all categories of the KOOS-questionnaire there is a difference in scores of about 20%. All articles reporting KOOS-scores see an improvement in all categories at final follow-up. As shown sport activities and quality of life are scored as being acceptable at final follow-up, which is important as they tend to state that their quality of life is below average before index surgery.

Figure 7.

Mean survival at final follow-up defined by three mean follow-up groups. It can be observed that data at long term follow-up has a bigger interval. Thus it seems there’s a heterogeneity among these studies. Indeed it could be observed that in this group articles who used subjective problems such as pain tend to report a lower mean survival rate. Furthermore studies with a follow-up of more than 20 years are depicted in the two outliers. This indicates that more research has to be done to evaluate the lifetime of a meniscal allograft using more uniform failure criteria.

Figure 8.

Mean survival at final follow-up by mean follow-up time. It is clearly depicted that the mean survival rate of the allograft linearly declines with follow-up time. As depicted at a mean follow-up time of 10–15 years almost half of the allografts tend to fail. The heterogeneous spreading of data at this mean follow-up time can be ascribed to the heterogenity of failure criteria used. The same can be stated for the outlier at a mean follow-up of seven years. Figure 7 also depicts tthat most of the data collected lies between a mean follow-up of 2–10 years.