Aims Inadvertent soft tissue damage caused by the oscillating saw during total knee arthroplasty (TKA) occurs when the sawblade passes beyond the bony boundaries into the soft tissue. The primary objective of this study is to assess the risk of inadvertent soft tissue damage during jig-based TKA by evaluating the excursion of the oscillating saw past the bony boundaries. The second objective is the investigation of the relation between this excursion and the surgeon’s experience level. Methods A conventional jig-based TKA procedure with medial parapatellar approach was performed on 12 cadaveric knees by three experienced surgeons and three residents. During the proximal tibial resection, the motion of the oscillating saw with respect to the tibia was recorded. The distance of the outer point of this cutting portion to the edge of the bone was defined as the excursion of the oscillating saw. The excursion of the sawblade was evaluated in six zones containing the following structures: medial collateral ligament (MCL), posteromedial corner (PMC), iliotibial band (ITB), lateral collateral ligament (LCL), popliteus tendon (PopT), and neurovascular bundle (NVB). Results The mean 75th percentile value of the excursion of all cases was mean 2.8 mm (SD 2.9) for the MCL zone, mean 4.8 mm (SD 5.9) for the PMC zone, mean 3.4 mm (SD 2.0) for the ITB zone, mean 6.3 mm (SD 4.8) for the LCL zone, mean 4.9 mm (SD 5.7) for the PopT zone, and mean 6.1 mm (SD 3.9) for the NVB zone. Experienced surgeons had a significantly lower excursion than residents. Conclusion This study showed that the oscillating saw significantly passes the edge of the bone during the tibial resection in TKA, even in experienced hands. While reported neurovascular complications in TKA are rare, direct injury to the capsule and stabilizing structures around the knee is a consequence of the use of a hand-held oscillating saw when making the tibial cut. Cite this article: Bone Joint J 2020;102-B(10):1324–1330.
Proposal of a New Reference Point to Determine the Tibial Resection Depth during Total Knee Arthroplasty for Valgus Knees
