Comparable long-term functional outcomes of subvastus and medial parapatellar approach in total knee arthroplasty: A 10-year follow-up study

Pooya Hosseini-Monfared; Alireza Mirahmadi; Shayan Amiri; Reza Minaie; Mohammad Hossein Ghafouri; Seyed Morteza Kazemi

doi:10.1002/jeo2.70035

Comparable long-term functional outcomes of subvastus and medial parapatellar approach in total knee arthroplasty: A 10-year follow-up study

J Exp Orthop. 2024 Oct 8;11(4):e70035. doi: 10.1002/jeo2.70035. eCollection 2024 Oct.

Authors

Pooya Hosseini-Monfared¹, Alireza Mirahmadi¹, Shayan Amiri², Reza Minaie¹, Mohammad Hossein Ghafouri¹, Seyed Morteza Kazemi¹

Affiliations

¹ Bone Joint and Related Tissues Research Center Shahid Beheshti University of Medical Sciences Tehran Iran.
² Shohadaye Haftom-e-Tir Hospital Iran University of Medical Sciences Tehran Iran.

Abstract

Background: Surgeons usually use the medial parapatellar or subvastus approaches for total knee arthroplasty (TKA). The subvastus approach is rapidly gaining recognition to reduce damage to the extensional mechanism and recover faster after surgery. This study compares the long-term outcomes of the conventional medial parapatellar and subvastus approaches in primary TKA during a minimum 10-year follow-up.

Methods: In a retrospective longitudinal follow-up study from 2008 to 2013, 60 eligible patients for primary TKA were included. The patients were divided into two groups: one undergoing TKA with the subvastus approach (n = 30) and the other with the conventional medial parapatellar approach (n = 30). Postoperatively, the patients were followed up for 10-15 years. Patients were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score (KSS), and Visual Analogue Scale index for pain.

Results: The time required to perform an active straight leg raise (SLR) was significantly shorter in the subvastus group (p < 0.001) at early postoperation evaluation. Patients in the subvastus group had lower pain and better knee functional scores at the one-year follow-up (p < 0.05). There was no difference between the two groups regarding duration of hospitalisation, blood loss, operation time, length of the scar, and postoperative complications. Both approaches had similar long-term results regarding pain and functional scores of WOMAC (6.2 ± 1.2 vs. 6.3 ± 1.3, p-value = 0.69) and KSS scores (93.1 ± 6.8 vs. 95.0 ± 3.2, p-value = 0.42).

Conclusion: The subvastus approach was associated with a shorter time to achieve active SLR, higher functional scores, and better pain relief at early postoperative evaluations. However, both techniques had similar long-term outcomes in terms of pain and functional scores, as measured by the WOMAC and KSS scales.

Level of evidence: II.

Keywords: KSS; WOMAC; medial parapatellar; subvastus; total knee arthroplasty.