Trivector Arthrotomy for TKR - a True Mechanical Approach for All Knees

Introduction:

During TKR it is mandatory to achieve perfect soft tissue balance and component alignment. As knee is covered in front by quadriceps mechanism, there is some manipulation of this structure while approaching knee for an arthroplasty. This alteration in Quadriceps mechanism can affect outcome of the surgery.

Aim:

To analyze the results of Trivector arthrotomy for TKR surgery.

Methods:

It is a study of 526 cases between 2008–2012. All the cases were performed by the author.

Inclusion criteria: Primary TKR with any degree of deformity.

Exclusion criteria: Revision TKR

Very fragile and thin patients.

Surgical Technique – Approach includes dividing distal 30% of vastus medialis, medial retinaculum 1 cm. medial to patella and patellar tendon distally up to Tibial tuberosity. This is raised as a single flap with knee in flexion. Patella is everted with knee in extension. Knee flexed and routine arthroplasty carried out. The watertight closure of the arthrotomy is by 1 no. vicryl interrupted stitches. (video clipping)

Results:

None of the cases were lost to FU. 323 cases Varus + FFD, 149 Varus, 35 Valgus, 14 hyperextension deformity, 5 neutral alignment cases were included. Results showed 87% pt.s at 1^st postop day and 96% by 4^th day regained ability to perform unassisted SLR. 4% had 5 to 10 degree quadriceps lag at discharge which recovered to neutral by 4 wks. The surgical field was adequate in all cases. KSS score improved from av. Pre op of 56 (38–71) to an average post op of 92 (84–96). All patients by 7 to 10 days were walking unaided or with a single cane in case of Bilateral TKRs.

Discussion:

Medial parapatellar arthrotomy divides the quadriceps tendon. The alteration in various vector limbs of Quadriceps can change the balance and laterally maltrack the patella. Incidence of Lateral release is higher in Medial parapatellar arthrotomy cases.

Mid and subvastus approaches are non extensile and hence poor visibility during surgery. Incidence of malalignment is higher when the visibility is poor.

Trivector arthrotomy approach is extensile and retains 70% strength of vastus medialis. At the closure the quads mechanism is perfectly aligned and hence the incidence of lateral release minimized. It is easily reproducible and can be used in stiff knees, severe varus, valgus, obese and post HTO TKRs with consistent results.

Conclusion:

The extensile nature of the approach and minimal disruption of the quadriceps mechanism encourages us to use this approach for all our cases. It is a true “Gateway” for all knees for TKRs.