Subvastus Lateralis Approach to Total Knee Arthroplasty – A Cadaveric Evaluation

Background Total knee arthroplasty (TKA) has been a reliable method for effectively treating advanced knee arthropathy. A medial parapatellar approach (MPA) is commonly used because of its large exposure and versatility; however, iatrogenic soft tissue damage remains a concern. In response, several alternative approaches have emerged that aim to reduce soft tissue damage, though their clinical usefulness is often limited by poor surgical exposure of the internal compartments of the knee. Based on the relevant surgical anatomy of the knee, we propose the subvastus lateralis approach (SLA) as a novel alternative. The aim of the present study is to explore the anatomical and surgical advantages of using the SLA compared to the MPA for TKA. Methods To compare surgical effectiveness, a TKA was conducted on 22 paired fresh‐frozen cadaveric limbs (five females/six males) randomly assigned to either the SLA or MPA. All procedures were conducted by the same experienced surgeon. Primary parameters measured were the perimeter of surgical exposure as well as the length of skin incision. Additionally, subjective observations of the medial and lateral patellar contact were noted to assess patellar tracking. Afterwards, gross dissection of the limb was conducted to analyze any disruptions in the following soft tissues: components of the extensor mechanism, iliotibial band, tendon of the popliteus, and medial/lateral collateral ligaments. Results The SLA provided adequate exposure to the internal compartments of the knee that was not statistically different to the mean exposure perimeter achieved using the MPA (p>0.05). Furthermore, the exposure provided by the SLA was achieved using a skin incision that was not statistically different compared to the MPA (p>0.05). In addition, patellar tracking showed superior results, where proper tracking was obtained in 100% of the SLA cases compared to 50% of those having undergone the MPA. Preliminary observations show that the SLA is successful in sparing the quadriceps tendon and the majority of the vastus lateralis. Conversely, in a subset of cases, the patellar ligament sustained a 0.1–0.7 mm transverse disruption of its distal fibers during the cutting of the tibial plateau. Conclusion The SLA to TKA was able to be successfully completed in 100% of the specimens, with no major modifications to the technique. This approach proved to be reliable in knees with no notable deformities (valgus or varus) and provided an equal exposure to the internal compartments of the knee when compared to the standard MPA. It is important to note that this exposure was achieved using a skin incision of similar length to the MPA. The SLA also shows promising results regarding proper patellar tracking, though future investigation should be conducted to objectively assert these benefits. Finally, preliminary results show a reduction in the disruption of the quadriceps tendon and muscles when using the SLA, however, damage to the patellar ligament may occur. Future studies should evaluate the versatility of the SLA through an examination of specimens with a known degree of knee deformity. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .