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. 2025 May 29:68:103078.
doi: 10.1016/j.jcot.2025.103078. eCollection 2025 Sep.

Robot-assisted total knee arthroplasty using modified sub-vastus approach: A series of 120 knees

B N Prashanth  1 , Karthik Sangani  1 , Yeshwanth M Reddy  1
Affiliations

Robot-assisted total knee arthroplasty using modified sub-vastus approach: A series of 120 knees

B N Prashanth et al. J Clin Orthop Trauma. .

Abstract

Background: The application of the Sub-vastus (SV) approach in Robot-assisted total knee arthroplasty (RATKA) is a relatively new practice with many potential benefits. This study aimed to assess the cases that underwent robot-assisted knee replacement through the sub-vastus approach, using functional and clinical parameters.

Methods: This monocentric, single-surgeon, retrospective observational study included 81 consecutive cases (120 knees) who had undergone Robot-assisted total knee arthroplasty with the Sub-vastus approach. Their Postoperative evaluation included hemoglobin levels, functional outcomes like the straight leg raising test (SLRT), walking ability, and the Oxford Knee Score (OKS).

Results: The average age of participants was 63.3 years. The mean hospital stay was 3.4 days (median 3 days). Perioperative drop in Hemoglobin concentration averaged 1.27 g/dl for unilateral and 1.5 g/dl for bilateral cases. By the second postoperative day, 85 % of the study group were able to perform active straight leg raising and 66 % were able to walk with support. These numbers increased to 95 % by the third day. The mean OKS was 45.832 (SD: 1.29).

Conclusion: The SV approach, when combined with RATKA, can yield improved functional results by showing the short-term benefits of a quadriceps-sparing technique, like less blood loss, faster recovery, and shorter hospital stay, while also enhancing surgical precision and accuracy in implant placement, thereby improving longevity. This combination is also effective in addressing severe deformities and obese cases, which previously were a limitation of the SV approach. Incorporating an oblique under-vastus release of the suprapatellar pouch and capsule was found to facilitate surgical access and may enhance procedural efficiency.

Keywords: Medial parapatellar approach; Robot assisted total knee arthroplasty; Subvastus approach; Total knee replacement; Undervastus modification.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

    1. Swank M.L., Alkire M., Conditt M., Lonner J.H. Technology and cost-effectiveness in knee arthroplasty: computer navigation and robotics. American Journal of Orthopedics (Belle Mead, N.J.) 2009;38(2 Suppl):32. - PubMed
    1. Bourne R.B., Chesworth B.M., Davis A.M., et al. Patient satisfaction after total knee arthroplasty: who is satisfied and who is not? Clin Orthop Relat Res. 2010;468(1):57. - PMC - PubMed
    1. Hofmann A.A., Plaster R.L., Murdock L.E. Subvastus (southern) approach for primary knee arthroplasty. Clin Orthop Relat Res. 1991;269:70. - PubMed
    1. Ghijselings I., Van den Wyngaert H., Demurie A., Van Onsem S., Delport H.P. The Eeklo modified subvastus approach for total knee arthroplasty: detailed surgical tips and tricks. J Orthoped SurgTech. 2021;4(1):246–253. doi: 10.36959/453/556. - DOI
    1. Hiranaka T., Tanaka T., Fujishiro T., et al. A modified under-vastus approach for knee arthroplasty with anatomical repair of soft tissue. Clin Orthop Surg. 2019;11(4):490–494. doi: 10.4055/cios.2019.11.4.490. - DOI - PMC - PubMed