PurposeExtra-articular femoral or tibial malunion can distort anatomical landmarks, compromise the reliability of conventional alignment guides, and complicate total knee arthroplasty (TKA). Robotic-assisted TKA (RA-TKA) may improve the precision and reproducibility of bone preparation and component positioning in these anatomically challenging cases. This study reports one-year clinical and radiographic outcomes after single-stage RA-TKA performed without corrective osteotomy in patients with post-traumatic extra-articular deformities.MethodsThis retrospective case series included nine patients (ten knees; one bilateral case) with symptomatic Kellgren-Lawrence grade 4 post-traumatic knee arthritis and associated extra-articular deformity who underwent CT-based RA-TKA using the Robotic Arm Interactive Orthopedic System (RIO; Mako SmartRobotics™, Stryker). Clinical outcomes included Knee Society Score (KSS 2011), Knee Injury and Osteoarthritis Outcome Score (KOOS), visual analogue scale (VAS) pain, and range of motion (ROM) assessed preoperatively and postoperatively at 2 weeks, 6 weeks, 3 months, and 1 year. Radiographic alignment was assessed using Hip-Knee-Ankle (HKA) angle on scanograms and arithmetic hip-knee-ankle angle (aHKA) derived from CT-based planning and intraoperative console values.ResultsMean HKA improved from 168.3° ± 3.8° preoperatively to 177.7° ± 1.4° postoperatively (mean correction 9.4° ± 2.8° toward neutral). Mean aHKA improved from -4.6° ± 5.0° to -0.6° ± 2.7° (mean correction +4.0°). Mean ROM increased from 95.5° ± 21.7° preoperatively to 119.5° ± 17.4° at 1 year. PROMs improved across timepoints. No major complications, including tracker pin site infection or periprosthetic fracture, were observed.ConclusionIn selected patients with post-traumatic extra-articular deformity deemed suitable for intra-articular compensation, single-stage RA-TKA without corrective osteotomy achieved consistent coronal alignment correction toward neutral and meaningful improvements in pain, ROM, and patient-reported outcomes at 1 year.

Keywords

(MeSH): arthroplasty; fracture malunion; knee; lower extremity deformities; osteoarthritis; replacement; robotic-assisted TKA; robotics.

1. Khanna, V., Sambandam, S. N., Ashraf, M., Mounasamy, V., & Kim, K. I. (2017). Extra-articular deformities in arthritic knees—a grueling challenge for arthroplasty surgeons: An evidence-based update. Orthopedic Reviews, 9(4), Article 7374. https://doi.org/10.4081/or.2017.7374
2. Hazratwala, K., O’Rourke, P., Ansari, M., & Mattei, J. A. (2016). Total knee arthroplasty in patients with extra-articular deformity. Arthroplasty Today, 2(1), 26–36. https://doi.org/10.1016/j.artd.2015.11.002
3. Wolff, A. M., Hungerford, D. S., & Pepe, C. L. (1991). The effect of extra-articular varus and valgus deformity on total knee arthroplasty. Clinical Orthopaedics and Related Research, 271, 35–51. https://doi.org/10.1097/00003086-199110000-00006
4. Evans, J. T., Walker, R. W., Evans, J. P., Blom, A. W., Whitehouse, M. R., & Sayers, A. (2019). How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports. The Lancet, 393(10172), 655–663. https://doi.org/10.1016/S0140-6736(18)32531-5
5. Price, A. J., Alvand, A., Troelsen, A., Katz, J. N., Roos, E. M., Manktelow, C. B., Woolf, A. D., & Beard, D. J. (2018). Knee replacement. The Lancet, 392(10158), 1672–1682. https://doi.org/10.1016/S0140-6736(18)32344-4
6. Veltman, E. S., van Wensen, R. J. A., Defoort, K. C., van Hellemondt, G. G., & Wymenga, A. B. (2017). Single-stage total knee arthroplasty and osteotomy as treatment of secondary osteoarthritis with severe extra-articular deformity. Knee Surgery, Sports Traumatology, Arthroscopy, 25(9), 2835–2840. https://doi.org/10.1007/s00167-015-3889-9
7. de Pablos Fernández, J., Arbeloa-Gutiérrez, L., & Arenas-Miquelez, A. (2019). One-stage total knee arthroplasty plus corrective osteotomy for severe extra-articular deformity. Arthroscopy Techniques, 8(11), e1403–e1410. https://doi.org/10.1016/j.eats.2019.07.020
8. Sun, J. Y., Zhang, G. Q., Shen, J. M., Ni, M., & Chen, J. Y. (2021). Single-stage total knee arthroplasty and femoral osteotomy for severe supracondylar deformity. Journal of Orthopaedic Surgery and Research, 16(1), Article 149. https://doi.org/10.1186/s13018-021-02293-w
9. Radke, S., & Radke, J. (2002). Total knee arthroplasty in combination with a one-stage tibial osteotomy: A technique for correction of a gonarthrosis with a severe (>15 degrees) tibial extra-articular deformity. The Journal of Arthroplasty, 17(5), 533–537. https://doi.org/10.1054/arth.2002.33269
10. Catonné, Y., Sariali, E., Khiami, F., Migaud, H., & Pasquier, G. (2019). Same-stage total knee arthroplasty and osteotomy for osteoarthritis with extra-articular deformity. Part I: Tibial osteotomy, prospective study of 26 cases. Orthopaedics & Traumatology: Surgery & Research, 105(6), 1047–1054. https://doi.org/10.1016/j.otsr.2019.04.010
11. Bargar, W. L. (2007). Robots in orthopaedic surgery: Past, present, and future. Clinical Orthopaedics and Related Research, 463, 31–36. https://doi.org/10.1097/BLO.0b013e318146874f
12. Jacofsky, D. J., & Allen, M. (2016). Robotics in arthroplasty: A comprehensive review. The Journal of Arthroplasty, 31(10), 2353–2363. https://doi.org/10.1016/j.arth.2016.05.026
13. Deckey, D. G., Rosenow, C. S., Verhey, J. T., Luu, A. N., Bingham, J. S., & Spangehl, M. J. (2021). Robotic-assisted total knee arthroplasty improves accuracy and precision compared to conventional techniques. The Bone & Joint Journal, 103-B(6 Suppl A), 74–80. https://doi.org/10.1302/0301-620X.103B6.BJJ-2020-2003.R1
14. Sodhi, N., Khlopas, A., Ehiorobo, J. O., Sultan, A. A., Chughtai, M., & Mont, M. A. (2019). Robotic-assisted total knee arthroplasty in the presence of extra-articular deformity. Surgical Technology International, 34, 497–502.
15. Kellgren, J. H., & Lawrence, J. S. (1957). Radiological assessment of osteo-arthrosis. Annals of the Rheumatic Diseases, 16(4), 494–502. https://doi.org/10.1136/ard.16.4.494
16. Scuderi, G. R., Bourne, R. B., Noble, P. C., Benjamin, J. B., Lonner, J. H., & Scott, W. N. (2012). The new Knee Society Knee Scoring System. Clinical Orthopaedics and Related Research, 470(1), 3–19. https://doi.org/10.1007/s11999-011-2135-0
17. Roos, E. M., Roos, H. P., Lohmander, L. S., Ekdahl, C., & Beynnon, B. D. (1998). Knee Injury and Osteoarthritis Outcome Score (KOOS)—Development of a self-administered outcome measure. Journal of Orthopaedic & Sports Physical Therapy, 28(2), 88–96. https://doi.org/10.2519/jospt.1998.28.2.88
18. Huskisson, E. C. (1974). Measurement of pain. The Lancet, 304(7889), 1127–1131. https://doi.org/10.1016/S0140-6736(74)90884-8
19. Paley, D., & Tetsworth, K. (1992). Mechanical axis deviation of the lower limbs: Preoperative planning of uniapical angular deformities of the tibia or femur. Clinical Orthopaedics and Related Research, 280, 48–64.
20. Gieroba, T. J., Marasco, S., Babazadeh, S., Dowsey, M. M., & Choong, P. F. M. (2023). Arithmetic hip–knee angle measurement on long-leg radiograph versus computed tomography—Inter-observer and intra-observer reliability. Arthroplasty, 5(1), Article 35. https://doi.org/10.1186/s42836-023-00193-4
21. Oussedik, S., Abdel, M. P., Victor, J., Pagnano, M. W., & Haddad, F. S. (2020). Alignment in total knee arthroplasty: What’s in a name? The Bone & Joint Journal, 102-B(3), 276–279. https://doi.org/10.1302/0301-620X.102B3.BJJ-2019-1729
22. Vedoya, S. P., & Sel, H. D. (2021). Total knee arthroplasty and extra-articular deformity: Deformity correction with intra-articular bone resections. 10 years follow up. Journal of Orthopaedics, 23, 219–224. https://doi.org/10.1016/j.jor.2021.01.007
23. Wang, J. W., & Wang, C. J. (2002). Total knee arthroplasty for arthritis of the knee with extra-articular deformity. The Journal of Bone and Joint Surgery. American Volume, 84(10), 1769–1774. https://doi.org/10.2106/00004623-200210000-00005
24. Rhee, S. J., Seo, C. H., & Suh, J. T. (2013). Navigation-assisted total knee arthroplasty for patients with extra-articular deformity. Knee Surgery & Related Research, 25(4), 194–201. https://doi.org/10.5792/ksrr.2013.25.4.194
25. Tigani, D., Masetti, G., Sabbioni, G., Busacca, M., Belluati, A., & Pignatti, G. (2012). Computer-assisted surgery as indication of choice: Total knee arthroplasty in case of retained hardware or extra-articular deformity. International Orthopaedics, 36(7), 1379–1385. https://doi.org/10.1007/s00264-011-1476-3