Transpatellar approach in lateral meniscal allograft transplantation using the keyhole method: can we prevent graft extrusion?

Purpose: technique for guide wire placement during meniscal allograft transplantation (MAT) is usually based on the parapatellar approach that is not in the anatomical direction of meniscal horn bony insertions. Here, we present a surgical technique to achieve the correct anatomical position of the meniscal graft using the transpatellar approach.
Methods: a guide wire was introduced through the patellar tendon in the direction of the meniscal insertion sites passing the lateral tibial spine. The insertion plane of the guide wire was approximately at the medial aspect of the tibial tuberosity and slightly medial to the midplane of the patellar tendon. After confirmation with C-arm, the guide wire was cut at the level just beneath the patellar tendon. The knee was then brought to the extension position which lessened the tension of the patellar tendon and retracted it to the medial aspect to expose the end of the guide wire. Drilling and insertion of bone block was performed accordingly.
Results: eleven consecutive patients with total or near-total meniscectomy of the knee underwent MAT with the described technique. The mean extrusion taken on 1-year postoperative non-weight-bearing MRI was 1.6 mm (range 0.5-2.9 mm). None of the patients presented with symptoms requiring a secondary surgery at the time of review.
Conclusion: the described technique focuses on achieving correct positioning of the tibia tunnel through the patellar tendon and tunnel reaming in the extended knee position via the mini-open parapatellar approach during lateral MAT. This "transpatellar approach" could be an effective method for anatomical placement of meniscal graft.