Key points
The evaluation of repaired BHMT could be performed by means of clinical assessment, second-look arthroscopic examination and MRI. None of them is completely accurate. Therefore, the present study performed the comparison among these three methods in an attempt to demonstrate their relationships.
Creativity
84% patients underwent second-look arthroscopic evaluation, which provided accurate data. We recommend individualized suture techniques according to the involved sides and zones of the BHMT, thus ensured a safe, stable, and optimal repair.
Analysis of BHMT repair
In the present study, the overall success rate was 92% including healed, incomplete healed, asymptomatic and partial symptomatic patients. And the success rate of 92% confirmed under second-look arthroscopy compares favorably with other studies. O’Shea and Shelbourne reported on 59 patients with BHMT repaired under arthroscopy followed by a second stage ACL reconstruction. His success rate was 89%, which was comparable to the present study[5]. In his study, the complete healing rate (55%) was lower and the incomplete healing rate (34%) was higher than those in our study. The reasons could be: ①the vascularity of the torn menisci played an essential role in the healing process. BHMTs were located mainly in white-white zone (43 in 55) [5], while all the tears in the study involved the red-red or red-white zone. ②The meticulous combined suture repair technique ensured stable suture of the menisci and improved suture fixation strength in the entire length, which guaranteed complete healing.
Characteristics of BHMT and its repair technique
BHMT is unstable injury of the meniscus, thus requiring stable repairs with good tissue reapproximation and solid suture strength. To achieve this goal, we combined all-inside and inside-out suture techniques according to the injured zones of menisci. Medial BHMT usually involves a greater portion of the meniscus. Due to the concern of vascular risks, repair of the medial BHMT is often insufficient. We used combined technique of inside-out technique for tears in middle and anterior 1/3 potions and all-inside technique for tears in the posterior horn through posteromedial portals, ensuring the vertical mattress suture in the entire length. Unlike medial BHMT, the main torn area of lateral BHMT usually located in the posterior 1/3 region, sometimes only involving the posterior popliteal tendon region. We performed all-inside suture technique through anteromedial portal for tears in posterior 1/3 potion and inside-out suture technique for tears in anterior popliteal tendon region.
Isolated use of meniscus fixator is not recommended for BHMT repair because its repair strength is weaker than vertical suture, especially for tears at synovial margin, and good tissue reapproximation could not be ensured by meniscus implants. Therefore, the suture repair technique is advocated in the treatment of BHMT.
Analysis of reasons for failure
Three of 5 failed repairs occurred with concurrent ACL surgery failure, including 2 reconstructed and 1 thermal shrinkage ACL. The reasons for other 2 failure cases remained unknown.
In the present study, failure of BHMT was highly associated with ACL deficiency, suggesting reliable ACL reconstruction to restore joint stability. ACL reconstruction could be done during menisci repair as presented in the present study or at a separate operation[5], which suggested staged operation for better rehabilitation. This study revealed one stage operation did not interfere with the recovery of joint range of motion. Passive knee extension exercises after surgery were important for patients with preoperational extension deficit due to a chronic locked knee situation. Besides, BHMT and ACL reconstruction follow the same rehabilitation protocol, indicating a benefit to reduce the patients’ rehabilitation period and their expense for treatment. Therefore, a same-stage BHMT repair and ACL reconstruction is recommended, and the period between stage operations should be shortened to avoid the influence on menisci healing due to an unstable joint.
Evaluation of meniscus repair
There are several means of evaluating meniscus healing status including second-look arthroscopy, MRI and clinical examination. Arthroscopic examination could evaluate the integrity and stability, but cannot verify the interstitial component healing status. There is also difficulty in defining complete healing and incomplete healing status.
The sensitivity and specificity of MR evaluating the repaired menisci remains controversial. In the present study, complete healing rate of 63% in MR was less than the ratio under arthroscopy (83%). The reasons may involve that grade 3 signal, mainly in the inferior surface, were identified in approximately 30% patients. More efforts should be paid to define which is more accurate in identifying the healing status of posterior horn and interstitial healing situation. MRI arthrography has been reported to provide higher sensitivity and specificity for healing of the postoperative meniscus[4].
Clinical symptoms are limited in evaluating the healing status of menisci. In the present study, 5 partial healed patients and 1 failed case were asymptomatic and 4 cases with joint line tenderness were completely healed under arthroscopy. These indicated that clinical symptoms could be absent in patients with partial healed or failed BHMT repairs.
Bias and limitations
Of 90 patients undergoing operation, only 68% were followed up. All-inside suture technique is technically demanding and time consuming, which could lead to tourniquet paralysis especially when performing a concurrent ACL reconstruction.
Conclusion
In conclusion, during a follow-up period of 2-5 years, repair of BHTMs in red-red or red-white zone, using combined inside-out and all-inside suture technique, with concurrent ACL reconstruction could achieve a success rate of 92%. In prevention of early occurrence of osteoarthropathy, BHTMs should be well repaired to prevent partial or total meniscectomy.
