Lateral posterior tibial slope does not affect femoral but does affect tibial tunnel widening following anatomic anterior cruciate ligament reconstruction using a Bone-Patellar Tendon-Bone graft

Application of multiplanar reconstruction and 3D printing in anterior cruciate ligament revision

OBJECTIVES

Anterior cruciate ligament injury is the most common type of knee joint ligament injury. Anterior cruciate ligament reconstruction has a high failure rate, with bone tunnel abnormalities as the most significant factor in these failures. Digital orthopedic technology can effectively develop implementation plans for the revision, thus increasing the success rate. This study aims to develop a surgical plan for anterior cruciate ligament revision by employing multiplanar reconstruction (MPR) for measuring bone tunnel position and diameter, and simulating bone tunnel creation via 3D printing preoperatively.

METHODS

A total of 12 patients who underwent anterior cruciate ligament revision at the Third Xiangya Hospital of Central South University between 2014 and 2021 were retrospectively studied. The data included patient demographics, preoperative formulated knee joint 3D printing models, and preoperative knee CT scans. The study measured the bone tunnel's diameter and position to guide the establishment of revision bone tunnels during surgery, reassessed the postoperative bone tunnels, and evaluated knee joint functional scores [including International Knee Documentation Committee Knee Evaluation Form (IKDC) score, Lysholm score, and Tegner exercise level score].

RESULTS

Preoperative measurements revealed suboptimal femoral tunnels positions in 4 patients and tibial tunnels positions in 2 patients. MPR and 3D printing technology were used to guide the establishment of a new bone canal during surgery, and postoperative measurements were satisfactory for all patients. Preoperative measurements demonstrated the interclass correlation coefficient for femoral tunnels and tibial tunnels diameters were 0.843 (P<0.05) and 0.889 (P<0.001), respectively. Meanwhile, the intraclass correlation coefficient were 0.811 (P<0.05) and 0.784 (P<0.05), respectively. The intraoperative diameter of femoral and tibial tunnels showed excellent correlation with postoperative CT measurements, with intraclass correlation coefficient values of 0.995 (P<0.001) and 0.987 (P<0.001), respectively. All bone tunnel positions were within the normal range. At the final follow-up, knee joint function scores in all 12 patients improved significantly compared to pre-surgery (P<0.001), and the reoperation rate was zero.

CONCLUSIONS

MPR and 3D printing technology can accurately measure the parameters of reconstructed anterior cruciate ligament bone tunnels. Personalized revision plans for patients with reconstruction failure enhances the success rate of revision surgery and improves patient prognosis.

Decreased posterior tibial slope is a risk factor for primary posterior cruciate ligament rupture and posterior cruciate ligament reconstruction failure: A systematic review

PURPOSE

To determine bony knee morphological factors associated with primary posterior cruciate ligament (PCL) rupture or PCL graft failure after PCL reconstruction.

METHODS

Three databases, namely MEDLINE, PubMed and EMBASE, were searched on 30th May 2023. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data such as receiver operating characteristic curve parameters, as well as p-values for comparisons of values between patients with PCL pathology and control patients, were recorded.

RESULTS

Nine studies comprising 1054 patients were included. Four studies reported that patients with PCL injury had flatter medial posterior tibial slopes (MTS) than controls, with mean values of 4.3 (range: 3.0-7.0) and 6.5 (range: 5.0-9.2) degrees, respectively. Two studies reported an MTS cutoff value ranging below 3.90-3.93° being a significant risk factor for primary PCL rupture or PCL graft failure. Two studies reported that shallow medial tibial depths were associated with primary PCL rupture, with mean values of 2.1 (range: 2.0-2.2) and 2.6 (range: 2.4-2.7) mm in PCL injury and control groups, respectively. Stenotic intercondylar notches and femoral condylar width were not consistently associated with PCL injuries.

CONCLUSION

Decreased MTS is associated with primary PCL rupture and graft failure after PCL reconstruction with values below 3.93° being considered as a significant risk factor. Less common risk factors include shallow medial tibial depth, while femoral condylar width and parameters with regards to the intercondylar notch, such as notch width, notch width index and intercondylar notch volume, demonstrated conflicting associations with primary or secondary PCL injuries.

LEVEL OF EVIDENCE

Level III.