From the Guidelines
The subvastus approach for total knee replacement can lead to several complications, including patellar complications such as subluxation, dislocation, fracture, component loosening or wear, impingement, and osteonecrosis, as well as periprosthetic infection, aseptic loosening, and osteolysis 1. The main complications of the subvastus approach include:
- Patellar complications, which occur in up to 5.2% of patients, usually within the first few postoperative years 1
- Periprosthetic infection, which is reported in 0.8% to 1.9% of TKAs 1
- Aseptic loosening, which is a common cause of TKA failure, especially in late stages (>2 years) 1
- Osteolysis, which is a leading cause of late TKA revision and can occur secondary to particle debris from polyethylene, cement, and metal 1
- Instability, which can result from surgical error, poor prosthesis selection, and malalignment, and can lead to revision surgery 1 Surgeons often experience a steeper learning curve with this approach, potentially leading to longer operative times initially. Patients may develop lateral retinacular pain from excessive retraction of the patella. There is also risk of injury to the saphenous nerve and its infrapatellar branch during dissection. Some patients experience postoperative hematoma formation or wound healing issues. While the subvastus approach theoretically preserves the quadriceps mechanism, excessive retraction can still cause temporary quadriceps weakness. According to the most recent study 1, aseptic loosening and osteolysis are significant complications that can lead to revision surgery, and instability can result in dislocation. It is essential to weigh these complications against the approach's potential benefits of faster quadriceps recovery and reduced postoperative pain when considering this technique for total knee arthroplasty.
From the Research
Complications of Subvastus Approach for Total Knee Replacement
The subvastus approach for total knee replacement has been studied in various research papers, with some complications noted.
- Displacement of the tibial tubercle osteotomy and delayed union of the osteotomy were reported in one study 2.
- Another study found that the subvastus approach resulted in fewer lateral releases and less peri-operative blood loss, but prolonged surgical times 3.
- A meta-analysis of randomized controlled trials found that the subvastus approach was associated with better outcomes in visual analog score (VAS), knee range of motion (ROM), straight leg raise, and lateral retinacular release, but there were no differences in total complications, wound infection, deep vein thrombosis, blood loss, and hospital stay between the subvastus and standard parapatellar approaches 4.
- A prospective, randomized, and blinded trial found that the subvastus approach offered early advantages over the standard parapatellar arthrotomy, including significantly earlier return of straight-leg raise, lower consumption of opiates, less blood loss, and greater knee flexion at 1 week 5.
- However, another study found that the subvastus approach was associated with two cases of delayed wound healing 6.
Comparison with Other Approaches
The subvastus approach has been compared to other approaches, such as the medial parapatellar approach, in several studies.
- One study found that the lateral subvastus approach with tibial tubercle osteotomy was a safe technique with an outcome comparable to that of the medial parapatellar approach, but with increased surgical time and specific complications 2.
- Another study found that the subvastus approach conferred superior results for time to regain an active straight leg raise, visual analogue score for pain, and total range of knee movement at one week, but there was no difference in Knee Society Score at six weeks or one year, or the rate of adverse events 3.