[Abstract] Objective To investigate the minimally invasive surgical technique, perioperative management and clinical outcomes of total arthroscopic combined meniscus transplantation and anterior cruciate ligament (ACL) reconstruction. Methods Minimally invasive arthroscopic meniscus transplantation with ACL reconstruction was performed in 8 patients with knee meniscectomy with ACL injury at the same time. The medial meniscus graft was fixed by anterior and posterior horn bone pins, and the lateral meniscus graft was fixed by anterior and posterior horn bone bridges; the ACL reconstruction was performed by autologous N cord tendon graft, internal button fixation at the femoral end and absorbable interface nail fixation at the tibial end. All surgical procedures were done under arthroscopy. Knee function was evaluated using Lysholm score and IKDC grading. The joint stability examination included Lachman test, drawer test and axial shift test. Knee mobility was evaluated by measuring the difference in bilateral knee mobility. The mean follow-up was 20.4 months (5 to 42 months). Results No cases in this group required ACL revision or removal of the transplanted meniscus due to graft failure. There was a 9°±6° reduction in flexion and a 3°±2° reduction in extension of the affected knee compared with the healthy side. The preoperative Lachman test was positive in 2 cases and 6 cases in 3 cases, the drawer test was positive in 3 cases and 5 cases in 3 cases, and the axial shift test was positive in all knees. The postoperative Lachman test of the affected knee was negative in 6 cases and positive in 1 case each for degree I and degree II. The anterior drawer test was negative in 6 cases and positive in 2 cases. The difference between the Lysholm score before and after surgery was statistically significant (P<0.01). ikdc classification of normal and near normal was statistically significant (P<0.01). The postoperative follow-up MRI showed that the ACL graft was appropriately positioned, and one case of the grafted meniscus had II degree damage signal shadowing in the anterior horn and one case of the posterior horn, while the rest of the meniscus was in good shape. Conclusion In appropriately selected patients with meniscectomy with ACL injury, combined meniscal transplantation with ACL reconstruction can better restore knee joint stability and improve function. Although the minimally invasive operation under total arthroscopy is technically difficult, this procedure is a treatment method with practical value.
[Keywords] Meniscus; transplantation, allograft; anterior cruciate ligament reconstruction; surgical technique, minimally invasive; arthroscopy
The meniscus and the anterior cruciate ligament (ACL) are interdependent and synergistic in maintaining knee stability [1,2]. patients with ACL injuries often have secondary meniscal injuries [3,4]; meniscectomized patients with ACL reconstruction often have ACL laxity [5]. Previously, patients with meniscectomy with ACL injury could only be treated with a single ACL reconstruction [5,6]. The development of meniscal transplantation techniques offers another option for such patients, namely, combined surgical treatment with meniscal transplantation and ACL reconstruction at the same time or in stages. Meniscal transplantation can enhance the stabilizing effect of ACL reconstruction on the knee joint, and ACL reconstruction can protect the transplanted meniscus, which can work together to better restore knee function and protect articular cartilage. However, there is no literature report and clinical experience of combined meniscal transplantation and ACL reconstruction in China. Since 2006, the authors have performed a minimally invasive total arthroscopic procedure combining meniscal transplantation and ACL reconstruction in patients with meniscectomy with ACL injury.
Materials and methods
Minimally invasive total arthroscopic surgery combining meniscus transplantation and ACL reconstruction was performed in 8 patients with meniscus resection or severe injury requiring total resection with ACL injury. Among them, 7 were male and 1 was female, with a mean age of 28.5 years (17-39 years). All patients had a history of trauma to the affected knee. Two cases had a positive Lachman test II and six cases had a positive Lachman test III, three cases had a positive drawer test II and five cases had a positive drawer test III, and all affected knees had a positive axial shift test. The mean interval from initial injury to meniscectomy was 17.5 months (0-48 months). The mean interval from meniscectomy to combined meniscal transplantation with ACL reconstruction was 9.8 months (0-42 months). medial meniscal transplantation was performed in 5 cases and lateral meniscal transplantation was performed in 3 cases.
I. Evaluation methods
Knee function was evaluated by Lysholm score and IKDC grading. The joint stability examination included Lachman test, drawer test and axial shift test. Knee mobility was evaluated by measuring the difference in extension and flexion mobility of both knees with a protractor. Routine radiographs and MR examinations were performed. MRI evaluation criteria of the meniscus were according to the method of Mink and Fischer [7,8]: grade 0 is a homogeneous low-signal shadow of the normal meniscus; grade I injury is a high-signal shadow in the shape of a sphere or irregular dot that does not extend to the surface of the meniscus; grade II injury is a high-signal shadow in the shape of a horizontal line that does not extend to the surface of the meniscus; grade III injury is an abnormal high-signal shadow that extends to the surface of the meniscus; grade IV injury is Grade IV injury is a change in the shape of the meniscus or formation of fragments. MRI evaluation of articular cartilage is based on Recht’s criteria [9]: grade 0, normal articular cartilage, or uniformly thin cartilage but smooth surface; grade I, loss of cartilage layering structure and limited low signal areas within the cartilage; grade II, mild to moderate irregularity of cartilage surface contour, depth of cartilage defect not reaching 50% of the full thickness; grade III, severe irregularity of cartilage surface contour, depth of cartilage defect reaching Grade III, severe irregularity of cartilage surface contour, depth of cartilage defect is more than 50% of the full thickness; Grade IV, full cartilage peeling and subchondral bone exposure.
Indications for surgery
The selection of this treatment modality was based on a subjective (pain, knee instability symptoms) and objective (meniscus, joint stability, articular cartilage, lower extremity force lines) evaluation of the patient. All patients in this group had varying degrees of pain and joint instability. The meniscus had been resected before surgery in 4 cases, and the meniscus needed to be completely resected in 4 cases with grade IV injury. The preoperative Lachman test of the affected knee was positive in 2 cases of grade II and 6 cases of grade III, the drawer test was positive in 4 cases of grade II and 4 cases of grade III, and the axial shift test was positive in all patients. According to the evaluation of the above criteria, six patients had grade I to II articular cartilage lesions, and two patients had small (<2 cm2) grade III articular cartilage lesions. All patients had bilateral lower extremity force lines measured and the difference was less than 4°. Severe articular cartilage damage and significant lower extremity force line abnormalities (not corrected) were not suitable for treatment by this procedure.
III. Surgical technique
The allograft meniscus was obtained, preserved, sterilized and matched to the recipient using previously reported methods [10]. The medial meniscus graft was fixed to the tibial plateau bone channel using anterior and posterior horn pins, and the lateral meniscus graft was embedded in the tibial plateau bone channel using a bone bridge [10]. , Fenland) fixation method.
Continuous epidural anesthesia was used and the knee joint stability was checked under anesthesia. The ACL, meniscus and articular cartilage were explored microscopically in a conventional knee arthroscopic position and with an anterior medial and lateral surgical approach. If a combined meniscal graft with ACL reconstruction is appropriate, the ipsilateral semitendinosus tendon and thin femoral tendon are taken in the usual way and the traction line is sutured at both ends after bifolding as an ACL reconstruction graft. The selected allograft meniscus was thawed and pretreated according to the procedure [10].
Arthroscopically clean the resected meniscus stump or remove the damaged meniscus that cannot be preserved until its circumference is 1 to 2 mm. A longitudinal incision of approximately 2 cm was made on the posterior lateral (lateral meniscus graft) or posterior medial (medial meniscus graft) joint line of the knee to expose the posterior joint capsule, and a puller was placed to facilitate suturing of the grafted meniscus to the posterior joint capsule to protect the neurovascular in the N fossa.
The meniscal graft was prepared in the tibial tract or groove as previously reported [10]. The tibial tract for ACL reconstruction was prepared arthroscopically according to the standard method, and the femoral tract for ACL reconstruction was prepared through a medial arthroscopic incision. The bone tract was enlarged to a diameter of approximately 8 mm according to the transverse meridian of the ACL graft.When the lateral meniscus was grafted, the ACL-reconstructed tibial bone tract often invaded the edge of the tibial bone groove of the meniscus graft (Figure 1), but did not affect the bone bridge embedding of the grafted meniscus. In the medial meniscus graft, the tibial bone tract used for posterior meniscus horn bone pin fixation is slightly lateral and distal to avoid traffic with the ACL reconstructed tibial bone tract.
The arthroscopic surgical incision was slightly enlarged (approximately 1.5-2 cm) and the transplanted meniscus was placed into the joint [10]. The ACL graft was then pulled into the tract with an appropriate internal button according to the length of the ACL femoral tract, and its femoral end was fixed with an internal button first. The meniscus was placed in the correct position under arthroscopic surveillance and fixed with sutures [10] (Figure 2). Finally, the ACL graft was pulled distally to complete multiple flexion and extension movements of the knee, and the ACL graft was tightened. The proximal tibia is moved as far back as possible relative to the distal femur in a 30° flexion position of the knee, and the tibial end of the ACL graft is fixed with an interface nail. In special cases, the distal traction line of the ACL graft can be fixed with additional anteromedial tibial screw suspension. Arthroscopic examination of the meniscus and ACL graft position, tension and intercondylar fossa for impingement is performed. The joint cavity was flushed, the surgical incision was closed and pressure bandaged, and the knee was fixed in extension with a hinge brace.
IV. Postoperative management
Immediately after surgery, we started isometric contraction exercises for the quadriceps and N cord muscles, avoiding weight bearing on the affected limb; after the local swelling decreased, we performed knee mobility training under the protection of a brace. Weight-bearing of the affected limb is started, and the knee brace is locked in extension during walking. At 24 weeks postoperatively, the mobility of the knee joint should reach normal, and normal walking with the protective brace removed, and water exercises should be practiced, but prolonged squatting, jumping and fast directional movements should be avoided; at 36 weeks postoperatively, light physical exercises such as running should be started; at 48 weeks postoperatively, all sports should be resumed.
V. Statistical analysis
SPSS13.0 statistical software (SPSS Inc., USA) was used, and t-test was used for the comparison of measurement data, and chi-square test was used for the comparison of count data. The test level α value was taken as 0.05 for both sides.
Results
The average follow-up of our cases was 20.4 months (5 to 42 months). There were no surgical side injuries, no serious complications such as infection, no significant allograft rejection, and no cases requiring ACL revision or removal of the transplanted meniscus due to graft failure. During the follow-up period, three patients had mild knee pain or swelling after exercise, while the rest had no pain, swelling or joint instability symptoms. The number of knee flexion on the affected side was 126°±13°, which was 9°±6° less than that on the healthy side. The number of knee extension on the affected side was 0°±5° which was 3°±2° less than the healthy side. Postoperatively, the Lachman test of the affected knee was negative in 6 cases, positive in 1 case in degree I and positive in 1 case in degree II. The anterior drawer test was negative in 6 cases and positive in 2 cases. The Lysholm score was 42.6 ± 11.3 preoperatively and 78.8 ± 15.7 at the last follow-up, with a statistically significant difference (t-test, P<0.01). ikdc classification was 1 preoperative grade b, 3 grade c and 4 grade d, and 4 grade a, 3 grade b and 1 grade c at the last follow-up. Normal and near normal (grade a and b) accounted for 12.5% preoperatively and 87.5% postoperatively, with statistically significant differences (x2 test, P<0.01). Postoperative radiographs showed proper bone tract position and reliable button fixation within the acl. Postoperative follow-up mri showed normal position of the acl graft, one case of graft anterior horn of meniscus and one case of graft posterior horn of meniscus had grade injury signal shadow (no clinical symptoms), and the rest had signal inhomogeneity inside the meniscus, which was in good shape. < p="">
Discussion
The meniscus has an important role in maintaining the dynamic balance of the knee joint [2,11-13]. Complete or major meniscal resection can affect knee function and induce degenerative changes in the articular cartilage, which are more severe when accompanied by ACL injury [1,11,13,14]. Since the meniscus and ACL have a significant synergistic role in maintaining normal knee function [2,11], ACL injury often induces meniscal injury [1,3,4] and meniscectomy can lead to ACL laxity [5]. Some findings suggest that the use of a single ACL reconstruction for meniscectomy with ACL injury may lead to ACL graft failure and surgical failure [2,5,15,16]. For this reason, we treated meniscectomized patients with ACL injury with a combined meniscal graft and ACL reconstruction using a minimally invasive arthroscopic technique. The results showed that the postoperative joint mobility was close to the level of the healthy limb in most patients, the joint stability check was basically normal, and the Lysholm score and IKDC score were significantly improved. We believe that treatment with combined meniscal transplantation and ACL reconstruction for meniscectomized patients with ACL injury for which there is an indication can better restore the stability of the knee joint, improve the function of the knee joint, and facilitate the prevention of degenerative changes in articular cartilage. Based on the results of this study and the physiological functions of the meniscus and ACL, we support that the transplanted meniscus and the reconstructed ACL have a protective effect on each other.
Single arthroscopic meniscal transplantation or ACL reconstruction has been reported in many cases [10,17-19]. The surgical technique of combined meniscal transplantation with ACL reconstruction currently lacks uniform specifications, especially the minimally invasive fully arthroscopic technique for this procedure is rarely reported [18]. In the fully arthroscopic minimally invasive surgical operation of combined meniscal transplantation with ACL reconstruction, although ACL injury allows the joint space to be stretched and widened, which facilitates the surgical operation of arthroscopic meniscal transplantation, there are many potential technical problems in the other surgical steps. It is generally considered that meniscal grafts are better fixed with bony fixation at the anterior and posterior corners than with soft tissue sutures [19], and we usually use two bony pins at the anterior and posterior corners for medial meniscal grafts and one bony bridge for lateral meniscal grafts [20,21]. Although the medial meniscus graft can also be fixed with a bone bridge embedded in the bone socket, we recommend not using a bone bridge fixation technique for the medial meniscus graft in combined meniscus graft and ACL reconstruction procedures, given the detrimental effect between the tibial bone tract of ACL reconstruction and the tibial bone socket of the medial meniscus graft. When the medial meniscus graft is fixed by the bone peg fixation technique, the anterior and posterior horn bone pegs are fixed to the tibial plateau through their respective tibial bone channels, in which the posterior horn bone channel of the meniscus may also traffic with the tibial bone channel of the reconstructed ACL, affecting the surgical operation and the fixation strength of the graft [22]. Therefore, it is advisable to set the locator at a lower angle (e.g., 45° to 55°) when establishing the tibial tract of the ACL and a higher angle (e.g., 60° to 65°) when establishing the posterior meniscal horn tract, with the difference in angle between the two tracts facilitating the separation of the tracts. In addition, reducing the bone tract as straight as possible according to the size of the graft also reduces the chance of traffic in the bone tract. We also recommend that the exit of the posterior meniscal horn bone tract on the anterior medial surface of the tibia be set as far outward as possible near the medial tibial tuberosity to facilitate separation from the ACL tibial bone tract exit.