Background
Biomechanical reports have advocated anatomic graft tunnel placement for reconstruction of the posterior cruciate ligament (PCL) to restore knee joint stability and facilitate optimal functional outcome. However, in vivo investigations that correlate the localization of the tunnel aperture to functional results are lacking so far.
Purpose
The objective of this study was to evaluate the anatomic accuracy of femoral and tibial tunnel apertures postoperatively using computed tomography (CT) and compare these findings to subjective and objective clinical outcome parameters in order to study the predictive effect of anatomic tunnel placement on functional results in vivo.
Methods
Twenty-six patients (mean age 35.0 ±13.0 years, m:f = 22:4) were prospectively followed for 3.2 ± 1.6 years after single-bundle all-inside arthroscopic tibial-inlay PCL reconstruction. VAS-, IKDC-, Tegner-, Lysholm-, KOOS- and osteoarthritis scores were obtained. Depending on the anatomic accuracy of femoral and tibial tunnel apertures measured on postoperative CT scans (within standard deviation from mean value), patients were stratified into two study groups. A threshold value for the centres of the tibial and femoral tunnel apertures was determined utilizing a measurement grid system as a radiographic reference to assess clinical group differences between anatomic and extra-anatomic tunnel positions.
Results
Average follow-up scores for the sample are: IKCD subjective 78.9 ± 19.0, Lysholm 78.8 ± 19.4, KOOS Symptoms 77.5 ± 17.0, KOOS Pain 81.8 ± 18.9, KOOS ADL 90.5 ± 13.6, KOOS Sports&Rec 68.1 ± 31.0, KOOS QOL 65.4 ± 26.1, Tegner 5 (1-9), VAS 2.4 ± 1.7, Kellgren präop 1 (1-2), Kellgren postop 1 (1-3), IKDC ROM A14 B2, Stability A10 B4 C2, Function A1 B11 C2 D2, Overall A1 B11 C2 D2. Functional outcome did not show any statistically significant differences between the study groups.
Conclusion
Arthroscopic tibial inlay reconstruction is an effective procedure and yields predictable functional results. Within a rather small sample size, the replication of the anatomical footprint of the PCL (within standard deviation from mean value) does not result in statistically significant differences regarding functional and radiological outcome parameters