The figure-of-nine leg position for anatomic anterior cruciate ligament reconstruction

Intraarticular lengths of double-bundle grafts can change during knee flexion: Intraoperative measurements in anatomic anterior cruciate ligament reconstructions

BACKGROUND

The lengths of the anteromedial bundle (AMB) and posterolateral bundle (PLB) change during knee motion in double-bundle anterior cruciate ligament (ACL) reconstruction. However, the actual intraarticular graft length would be affected by the bone tunnel position and tunnel creation angle during ACL reconstruction. The aim of this study was to investigate the intraarticular length change of the AMB and PLB in patients who underwent anatomic double-bundle ACL reconstruction.

HYPOTHESIS

We hypothesized that the PLB would show a more dynamic length change pattern than the AMB during knee flexion at ACL reconstruction.

METHODS

Thirty-two patients (16 men and 16 women) who had isolated ACL injuries with intact menisci were investigated. Anatomic double-bundle ACL reconstructions were performed using semitendinosus tendon autografts at a mean age of 30.6 years. The graft and tunnel lengths were measured intraoperatively. Intraarticular graft lengths and length changes were calculated at 0° and 90° of knee flexion during ACL reconstruction. Intraoperative data were collected prospectively, and analyses were performed retrospectively.

RESULTS

The intraarticular length of the AMB at 0° of knee flexion was 28.1±5.5mm. At 90° of knee flexion, the AMB intraarticular length decreased to 25.6±4.8mm. The intraarticular length of the PLB decreased to 17.7±4.6mm at 90° of knee flexion compared to 22.0±4.2mm at 0° of knee flexion. Changes in the intraarticular graft length during knee flexion were detected more in the PLB (4.1mm) than in the AMB (2.0mm, p=0.01).

DISCUSSION

This study demonstrated that the intraarticular length change of the PLB during knee motion was larger than that of the AMB in anatomic double-bundle ACL reconstructions with semitendinosus tendon autografts and suspensory femoral fixation devices.

LEVEL OF EVIDENCE

IV; retrospective cohort study.

Early chondral damage following meniscus repairs with anterior cruciate ligament reconstruction

Background

Meniscal tears are commonly observed in patients with anterior cruciate ligament (ACL) injuries. Meniscal repair has become a common procedure for the injured meniscus, and good clinical outcomes have been reported in such cases when used concurrently with ACL reconstruction. However, it is unclear whether early chondral damage progression can be prevented following meniscal repair with ACL reconstruction, as meniscal damage is a potential risk factor for the development of osteoarthritis. The purpose of this study was to evaluate the zone-specific chondral damage that occurs after arthroscopic meniscal repair with concomitant ACL reconstruction. Our hypothesis was that meniscal repair with ACL reconstruction would not decrease the rate of progression of chondral damage compared to that observed in isolated ACL reconstruction with intact menisci.

Methods

This study included 40 patients who underwent anatomic double-bundle ACL reconstruction. We divided the patients into the following two groups: Group A with an intact meniscus (20 knees) and Group M requiring meniscal repair (20 knees). Chondral damage was evaluated arthroscopically in six compartments and 40 sub-compartments, and these features were graded using the International Cartilage Repair Society lesion classification. The cartilage damage in each sub-compartment and compartment was compared between the two groups both at reconstruction and at second-look arthroscopy (average 16 months postoperatively). At the latest follow-up examination (average 37 months postoperatively), the International Knee Documentation Committee (IKDC) score was compared between the two groups.

Results

Group M had a significantly worse cartilage status than Group A in five sub-compartments (mainly in the medial compartment) at reconstruction and in nine sub-compartments (mainly in the bilateral compartments) at second-look arthroscopy. The mean IKDC score was better in Group A than in Group M (Group A; 90 vs. Group M; 86). The overall success rate of meniscal repairs was 92% (23 of 25 menisci) at second-look arthroscopy.

Conclusion

The progression of post-traumatic chondral damage may occur at a faster rate in patients who require ACL reconstruction and meniscal repair than in patients with intact menisci.

Posttraumatic cartilage degradation progresses following anterior cruciate ligament reconstruction: A second-look arthroscopic evaluation

BACKGROUND

Several studies have demonstrated that posttraumatic knee osteoarthritis progresses even after anterior cruciate ligament reconstruction. Few reports described zone-specific cartilaginous damages after anterior cruciate ligament reconstruction. This study aimed to compare the status of articular cartilage at anterior cruciate ligament reconstruction with that at second-look arthroscopy.

METHODS

This study included 20 patients (20 knees, 10 males and 10 females, mean age 22.4 years, Body mass index 24.4 kg/m²) that underwent arthroscopic anatomic double-bundle anterior cruciate ligament reconstruction and second-look arthroscopy. Mean periods from injury to reconstruction and from reconstruction to second-look arthroscopy were 3.4 and 15.3 months, respectively. Cartilage lesions were evaluated arthroscopically in the 6 articular surfaces and 40 articular subcompartments independently, and these features were graded with the International Cartilage Repair Society articular cartilage injury classification; comparisons were made between the grades at reconstruction and at second-look arthroscopy. Furthermore, clinical outcomes were assessed at reconstruction and at second-look arthroscopy, using the Lysholm knee score, Tegner activity scale, International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, side-to-side difference of the KT-2000 arthrometer, and pivot shift test.

RESULTS

Each compartment showed a deteriorated condition at second-look arthroscopy compared with the pre-reconstruction period. A significant worsening of the articular cartilage was noted in all compartments except the lateral tibial plateau and was also observed in the central region of the medial femoral condyle and trochlea after reconstruction. However, each clinical outcome was significantly improved postoperatively.

CONCLUSIONS

Good cartilage conditions were restored in most subcompartments at second-look arthroscopy. Furthermore, posttraumatic osteoarthritic changes in the patellofemoral and medial compartments progressed even in the early postoperative period, although good knee stability and clinical outcomes were obtained. Care is necessary regarding the progression of osteoarthritis and the appearance of knee symptoms in patients undergoing anterior cruciate ligament reconstruction.

Meniscal repair concurrent with anterior cruciate ligament reconstruction restores posterior shift of the medial meniscus in the knee-flexed position

PURPOSE

The purpose of this study was to evaluate the shape and shift of the medial meniscus before and after meniscal repair concurrent with anterior cruciate ligament (ACL) reconstruction using magnetic resonance imaging (MRI) at 90° of knee flexion.

METHODS

This study included 18 patients with ACL-deficient knees without meniscus tears (group A), 11 patients with medial meniscus tears alone (group M), and 15 patients with ACL-deficient knees complicated with medial meniscus tears (group AM). The posterior segment shape was evaluated using open MRI at 90° of knee flexion preoperatively and at 3 months postoperatively. The length, height, width, and posterior extrusion of the medial meniscus and posterior tibiofemoral distance were measured. These measurements were compared between the three groups.

RESULTS

On preoperative MRI, a significant difference was observed in the posterior extrusion of the medial meniscus (group A, 1.2 ± 0.5 mm; group M, 1.7 ± 0.3 mm; group AM, 4.1 ± 1.5 mm, p < 0.001). All parameters did not differ between the three groups on postoperative MRI. In addition, the posterior width and extrusion of the medial meniscus were decreased significantly after meniscal repair concurrent with ACL reconstruction.

CONCLUSIONS

This study demonstrated that the medial meniscus shifted posteriorly at 90° of knee flexion in ACL-deficient knees complicated with medial meniscus tears. Medial meniscal repair concurrent with ACL reconstruction improved the deformed morphology and posterior extrusion. MRI measurements of the posterior extrusion at the knee-flexed position may be clinically useful to assess the functional improvement of the medial meniscus following meniscal repair combined with ACL reconstruction.

LEVEL OF EVIDENCE

III.

Improvement in the medial meniscus posterior shift following anterior cruciate ligament reconstruction

PURPOSE

Anterior cruciate ligament (ACL) reconstruction can reduce the risk of developing osteoarthritic knees. The goals of ACL reconstruction are to restore knee stability and reduce post-traumatic meniscal tears and cartilage degradation. A chronic ACL insufficiency frequently results in medial meniscus (MM) injury at the posterior segment. How ACL reconstruction can reduce the deformation of the MM posterior segment remains unclear. In this study, we evaluated the form of the MM posterior segment and anterior tibial translation before and after ACL reconstruction using open magnetic resonance imaging (MRI).

METHODS

Seventeen patients who underwent ACL reconstructions without MM injuries were included in this study. MM deformation was evaluated using open MRI before surgery and 3 months after surgery. We measured medial meniscal length (MML), medial meniscal height (MMH), medial meniscal posterior body width (MPBW), MM-femoral condyle contact width (M-FCW) and posterior tibiofemoral distance (PTFD) at knee flexion angles of 10° and 90°.

RESULTS

There were no significant pre- and postoperative differences during a flexion angle of 10°. At a flexion angle of 90°, MML decreased from 43.7 ± 4.5 to 41.4 ± 4.5 mm (P < 0.001), MMH from 7.5 ± 1.4 to 6.9 ± 1.4 mm (P = 0.006), MPBW from 13.1 ± 2.0 to 12.2 ± 1.9 mm (P < 0.001) and M-FCW from 10.0 ± 1.5 to 8.5 ± 1.5 mm (P < 0.001) after ACL reconstruction. The PTFD increased from 2.1 ± 2.8 to 2.7 ± 2.4 mm after ACL reconstruction (P = 0.015).

CONCLUSIONS

ACL reconstruction affects the contact pattern between the MM posterior segment and medial femoral condyle and can reduce the deformation of the MM posterior segment in the knee-flexed position by reducing abnormal anterior tibial translation. It possibly prevents secondary injury to the MM posterior segment and cartilage that progresses to knee osteoarthritis.

LEVEL OF EVIDENCE

IV.

The anterior cruciate ligament-lateral meniscus complex: A histological study

The anterior root of the lateral meniscus (LM) dives underneath the tibial attachment of the anterior cruciate ligament (ACL). Although the distinct role of meniscal attachments has been investigated, the relationship between the LM anterior insertion (LMAI) and ACL tibial insertion (ACLTI) remains unclear. This study histologically analyzed the LMAI and ACLTI. Samples were divided into four regions in an anterior-to-posterior direction. Histological measurements of these insertion sites were performed using safranin O-stained coronal sections. Distribution and signal densities of type I and II collagen were quantified. The ACLTI and LMAI formed the ACL-LM complex via fiber connections. The anterior part of the ACLTI had a widespread attachment composed of dense fibers. Attachment fibers of the LMAI became dense and wide gradually at the middle-to-posterior region. The ACL-LM transition zone (ALTZ) was observed between the LMAI and the lateral border of the ACLTI at the middle part of the ACL tibial footprint. Type II collagen density of the LMAI was higher than that of the ACLTI and ALTZ. Our results can help create an accurate tibial bone tunnel within the dense ACL attachment during ACL reconstruction surgery.

Postoperative change in the length and extrusion of the medial meniscus after anterior cruciate ligament reconstruction

PURPOSE

The medial meniscus is a secondary stabilizer of anterior tibial translation in anterior cruciate ligament (ACL)-deficient knees. ACL reconstruction effectively restores an increased anterior tibial translation in the ACL-deficient knee. However, knee osteoarthritis sometimes develops in ACL-reconstructed patients during a long-term follow-up period. We hypothesized that the medial meniscal position would be different between the ACL-deficient and reconstructed knees. The aim of this study was to investigate pre-operative and postoperative location of the medial meniscus in patients who underwent ACL reconstruction.

METHODS

ACL-reconstructed knees (28 knees) and normal knees (27 knees) were investigated. Medial tibial plateau length (MTPL) and medial tibial plateau width (MTPW) were determined using radiographic images. Magnetic resonance imaging (MRI)-based medial meniscal length (MML), medial meniscal width (MMW), and medial meniscal extrusion (MME) were measured. Postoperative change in the MML, MMW, and MME were evaluated and compared with those in normal knees.

RESULTS

No significant differences between the ACL-deficient (pre-operative) and normal groups were noted. The ACL-reconstructed (postoperative) group showed an increase in the MML, in the percentage of the MML (%MML = 100 MML/MTPL), and in the MME. Significant differences between postoperative and normal groups were observed in the MML, %MML, and MME. MMW and MMW percentage (100 MMW/MTPW) were similar in all groups.

CONCLUSIONS

The anteroposterior length and radial extrusion of the medial meniscus increased after ACL reconstruction. Transposition of the medial meniscus may be a possible cause of developing further degenerative knee joint disorders after ACL reconstruction.