Morphological parameters of patellar position depending on the joint line obliquity in knee osteoarthritis
DOI:
https://doi.org/10.14739/mmt.2026.1.343256Keywords:
knee joint, osteoarthritis, degenerative–dystrophic diseases, gonarthrosis, morphologyAbstract
Aim. To analyze the differences in the morphological parameters of patellar position depending on the joint line obliquity, as determined using the authors’ proprietary method, in patients with medial knee osteoarthritis.
Materials and methods. Radiographic indices of patellar position were analyzed in 45 patients with medial knee osteoarthritis (n = 62 knees). The mean age of the patients was 63.84 ± 8.21 years. The following radiographic indices were calculated: Insall–Salvati, Caton–Deschamps, Grelsamer–Meadows, and Blackburne–Peel. Lateral knee radiographs were obtained with the joint flexed at 30°. The modified joint line obliquity (mJLO) angle was assessed according to the authors’ original method. An mJLO value of <177° was classified as apex distal (AD), 177–183° as apex neutral (AN), and >183° as apex proximal (AP). Statistical analysis was performed using Statistica 13 and RStudio software. The level of statistical significance was set at p ≤ 0.05.
Results. AD was identified in 43 (69.35 %) cases, AN in 16 (25.81 %), and AP in 3 (4.84 %). The mean mJLO value was 172.40 ± 4.05° in the AD group, 179.25 ± 1.81° in the AN group, and 187.33 ± 2.52° in the AP group (p < 0.00001). Significant differences were found among the groups in the mean values of the Insall–Salvati (p = 0.04), Caton–Deschamps (p = 0.01), and Blackburne–Peel (p = 0.01) indices. Signs of patella alta were more frequently observed in the AP group, whereas normal or low patellar positions predominated in the AD and AN groups. A higher patellar position was demonstrated in patients with a more proximal joint line inclination, confirmed by significant correlations: Insall–Salvati ratio (τ = +0.24, p = 0.006), Caton–Deschamps index (τ = +0.18, p = 0.04), Grelsamer–Meadows index (τ = +0.23, p = 0.009), and Blackburne–Peel ratio (τ = +0.27, p = 0.002). Predictive indicators of AD included: Insall–Salvati ratio 0.8–1.2 (OR = 4.39, CI (1.44–15.02), p = 0.009), Grelsamer–Meadows index <2 (OR = 4.39, CI (1.44–15.02), p = 0.009), and Blackburne–Peel ratio <0.8 (OR = 4.01, CI (1.31–12.89), p = 0.02). Probable predictors of AP were: Caton–Deschamps index >1.2 (OR = 833.00, CI (32.60–273970.85), p = 0.000004) and Blackburne–Peel ratio >1.0 (OR = 86.33, CI (6.90–12346.04), p = 0.0003).
Conclusions. Morphological parameters of patellar position are sensitive indicators of biomechanical alterations in medial knee osteoarthritis that depend on mJLO values. This supports their inclusion in a comprehensive radiometric program for personalized surgical planning.
References
Giorgino R, Albano D, Fusco S, Peretti GM, Mangiavini L, Messina C. Knee Osteoarthritis: Epidemiology, Pathogenesis, and Mesenchymal Stem Cells: What Else Is New? An Update. Int J Mol Sci. 2023;24(7):6405. doi: https://doi.org/10.3390/ijms24076405
Jang S, Lee K, Ju JH. Recent Updates of Diagnosis, Pathophysiology, and Treatment on Osteoarthritis of the Knee. Int J Mol Sci. 2021;22(5):2619. doi: https://doi.org/10.3390/ijms22052619
Lee SH, Yoo JH, Kwak DK, Kim SH, Chae SK, Moon HS. The posterior tibial slope affects the measurement reliability regarding the radiographic parameter of the knee. BMC musculoskeletal disorders. 2024;25(1):202. doi: https://doi.org/10.1186/s12891-024-07330-3
Konrads C, Schreiner AJ, Cober S, Schüll D., Ahmad SS, Alshrouf MA. Evaluation of patella height in native knees and arthroplasty: an instructional review. SICOT-J. 2022;8:36. doi: https://doi.org/10.1051/sicotj/2022037
Arias C, Lustig S. Physiopathology of patello-femoral osteoarthritis: current concepts. J ISAKOS. 2024;9(4):806-813. doi: https://doi.org/10.1016/j.jisako.2024.06.004
Brutico J, Paul RW, Wright M, Destine H, Johnson EE, Bishop ME, et al. Preoperative Patella Alta on Caton-Deschamps Index Is a Predictor of Outcome Following Isolated Medial Patellofemoral Ligament Reconstruction. Arthrosc Sports Med Rehabil. 2023;5(2):e523-e528. doi: https://doi.org/10.1016/j.asmr.2023.02.006
Schreiner AJ, Spiegel L, Yan SG, Konrads C, Erne F, Hemmann P, et al. Evaluation of modified and newly applied patella height indices in primary total knee arthroplasty. Skeletal Radiol. 2023;52(1):73-82. doi: https://doi.org/10.1007/s00256-022-04142-1
Yang Z, Shen M, Xie D, Zhang J, Wei Q. Correlation between severity of knee joint osteoarthritis and alignment of patellofemoral and patellar height on radiographs. Chin Med J (Engl). 2025;138(8):947-52. doi: https://doi.org/10.1097/CM9.0000000000003392
Vella-Baldacchino M, Cipolla A, Asghar Z, LiArno S, Faizan A, Argenson J-N, et al. Patella height ratios diagnose the same healthy knees differently. Sci Rep. 2025;15:89. doi: https://doi.org/10.1038/s41598-024-83663-2
Pratobevera A, Seil R, Menetrey J. Joint line and knee osteotomy. EFORT Open Rev. 2024;9(5):375-86. doi: https://doi.org/10.1530/EOR-24-0037
Insall J, Salvati E. Patella position in the normal knee joint. Radiology. 1971;101(1):101-4. doi: https://doi.org/10.1148/101.1.101
Caton J, Deschamps G, Chambat P, Lerat JL, Dejour H. Les rotules basses. A propos de 128 observations [Patella infera. Apropos of 128 cases]. Rev Chir Orthop Reparatrice Appar Mot. 1982;68(5):317-25. French.
Grelsamer RP, Meadows S. The modified Insall-Salvati ratio for assessment of patellar height. Clin Orthop Relat Res. 1992;(282):170-6.
Blackburne JS, Peel TE. A new method of measuring patellar height. J Bone Joint Surg Br. 1977;59(2):241-2. doi: https://doi.org/10.1302/0301-620X.59B2.873986
Kylymniuk L, Matsipura M, Iaremyn S. [Variations in patellar position according to knee joint morphotype in patients with osteoarthritis]. Pain, joints, spine. 2025;15(2):61-9. Ukrainian. doi: https://doi.org/10.22141/pjs.15.2.2025.462
Cassar-Pullicino VN, Davies AM, editors. Measurements in musculoskeletal radiology. 2020d. Berlin, Germany: Springer; 2020. Available from: https://doi.org/10.22141/pjs.15.2.2025.462
MacDessi SJ, Griffiths-Jones W, Harris IA, Bellemans J, Chen DB. Coronal Plane Alignment of the Knee (CPAK) classification. Bone Joint J. 2021;103-B(2):329-37. doi: https://doi.org/10.1302/0301-620X.103B2.BJJ-2020-1050.R1
Unal M, Ercan S, Budeyri A, Toprak U, Şalkaci A. Anatomical axis validation of lower extremity for different deformities: A radiological study. SAGE Open Med. 2020;8:2050312120923822. doi: https://doi.org/10.1177/2050312120923822
The World Medical Association. (1964/2013). Declaration of Helsinki: Ethical Principles for Medical Research Involving Human Subjects [Internet]. Ferney-Voltaire: WMA; 2013 [cited 2025 Jun 9]. Available from: https://www.wma.net/what-we-do/medical-ethics/declaration-of-helsinki/
Council of Europe. Konventsiia pro zakhyst prav liudyny ta hidnosti liudyny shchodo zastosuvannia biolohii ta medytsyny: Konventsiia pro prava liudyny ta biomedytsynu [Convention for the protection of human rights and dignity of the human being with regard to the application of biology and medicine: convention on human rights and biomedicine] [Internet]. Strasbourg: Council of Europe; 1997 [cited 2025 Jul 9]. Available from: https://zakon.rada.gov.ua/laws/show/994_334#Text
Ministry of Health of Ukraine. Pro zatverdzhennia poriadku provedennia klinichnykh vyprobuvan likarskykh zasobiv ta ekspertyzy materialiv klinichnykh vyprobuvan ta typovoho polozhennia pro etychni komitety [On approval of the Procedure for conducting clinical trials of medicinal products and examination of clinical trial materials and the Model Regulation on ethics committees] Order dated 2009 Sep 23, no. 690. [cited 2025 Jul 9]. Available from: https://zakon.rada.gov.ua/laws/show/z1010-09#Text
Kim SE, Yun KR, Lee JM, Lee MC, Han HS. Preserving coronal knee alignment of the knee (CPAK) in unicompartmental knee arthroplasty correlates with superior patient-reported outcomes. Knee Surg Relat Res. 2024;36(1):1. doi: https://doi.org/10.1186/s43019-023-00204-3
Agarwal S, Ayeni FE, Sorial R. Impact of change in coronal plane alignment of knee (CPAK) classification on outcomes of robotic-assisted TKA. Arthroplasty. 2024;6(1):15. doi: https://doi.org/10.1186/s42836-024-00239-1
Corban LE, van de Graaf VA, Chen DB, Wood JA, Diwan AD, MacDessi SJ. How often do we alter constitutional limb alignment, joint line obliquity, and Coronal Plane Alignment of the Knee (CPAK) phenotype when performing mechanically aligned TKA? Bone Jt Open. 2024;5(2):109-16. doi: https://doi.org/10.1302/2633-1462.52.BJO-2023-0122
Şenel A, Eren M, Sert S, Gürpınar T, Çarkçı E, Polat B. Phenotyping of the Turkish population according to Coronal Plane Alignment of the Knee classification: A retrospective cross-sectional study. Jt Dis Relat Surg. 2024;35(1):194-201. doi: https://doi.org/10.52312/jdrs.2023.1464
Lee H, Fletcher C, Hartwell M, Strickland SM. Effect of Patellofemoral Arthroplasty on Patellar Height in Patients with Patellofemoral Osteoarthritis. J Knee Surg. 2023;36(12):1283-8. doi: https://doi.org/10.1055/s-0042-1755354
Wang Y, Lu J, Wang Z, Li Z, Pan F, Zhang M, et al. The association between patella alignment and morphology and knee osteoarthritis. J Orthop Surg Res. 2024;19(1):509. doi: https://doi.org/10.1186/s13018-024-05001-6
Arslan FZ, Oğuzdoğan GY. A novel assessment of the differences in various measurements in patients with patella alta and baja: a retrospective cross-sectional study. Quant Imaging Med Surg. 2024;14(12):9497-505. doi: https://doi.org/10.21037/qims-23-1722
Analan PD, Ozdemir H. The Effect of Patellar Height by Using Insall Salvati Index on Pain, Function, Muscle Strength and Postural Stability in Patients with Primary Knee Osteoarthritis. Curr Med Imaging. 2021;17(4):532-8. doi: https://doi.org/10.2174/1573405616999200817172649
D'Ambrosi R, Rubino F, Ursino C, Mariani I, Ursino N, Formica M, et al. Change in patellar height in medial and lateral unicompartmental knee arthroplasty: a clinical trial. Arch Orthop Trauma Surg. 2024;144(3):1345-52. doi: https://doi.org/10.1007/s00402-023-05139-8
Sahanand KS, Pandian P, Chellamuthu G, Rajan DV. Effect of ascending and descending medial open wedge high tibial osteotomy on patella height and functional outcomes-a retrospective study. Eur J Orthop Surg Traumatol. 2024;34(1):499-505. doi: https://doi.org/10.1007/s00590-023-03693-w
Kudo Y, Maeyama A, Ishimatsu T, Matsunaga T, Hara J, Arima H, et al. Changes in patellar baja progress until 3 months after medial open-wedge high tibial osteotomy. J Orthop Surg (Hong Kong). 2022;30(3):10225536221128615. doi: https://doi.org/10.1177/10225536221128615
Luceri F, Basilico M, Batailler C, Randelli PS, Peretti GM, Servien E, et al. Effects of sagittal tibial osteotomy on frontal alignment of the knee and patellar height. Int Orthop. 2020;44(11):2291-8. doi: https://doi.org/10.1007/s00264-020-04580-3
Sim JA, Na YG, Lee BK, Lee BH. Alignment changes after open-wedge high tibial osteotomy result in offloading in the patellofemoral joint: a SPECT/CT analysis. Knee Surg Sports Traumatol Arthrosc. 2022;30(2):437-46. doi: https://doi.org/10.1007/s00167-020-06115-0
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