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. 2025 Feb 5.
doi: 10.1007/s12306-025-00884-y. Online ahead of print.

Significance of tibial-tubercle trochlear groove distance and adjunctive radiological parameters in patients with recurrent patellar instability

Affiliations

Significance of tibial-tubercle trochlear groove distance and adjunctive radiological parameters in patients with recurrent patellar instability

W Lim et al. Musculoskelet Surg. .

Abstract

Purpose: Magnetic resonance imaging (MRI) is often used to evaluate patients with patellar dislocations to facilitate diagnosis and management strategies. Many radiological parameters have been described in the literature. The aim of this study was to assess the significance of tibial-tubercle trochlear groove distance (TT-TG) distance and other MRI measurements in patients with and without patellar instability.

Methods: This case-control study included 41 patients with recurrent patellar instability and 50 patients with stable knees, all of whom underwent MRI scans. A total of 19 radiological parameters were measured in both groups.

Results: All measured MRI parameters had statistically significant differences between both groups (p < 0.05) apart from trochlear cartilage length. TT-TG distance. 20 mm had the strongest association with patellar instability (OR 53.3, p = 0.006, 95%CI [3.1- 927.4]) and the highest specificity (100%) but had the lowest sensitivity (34%) out of all the measured parameters. TT-TG. 13 mm had a higher sensitivity (68%) but lower specificity (72%) and weaker association with patellar instability (OR 5.5, p < 0.001, 95%CI [2.2. 13.7]). TT-TG/trochlear articular cartilage width ratio also had a strong association with patellar instability (OR 14.7, p < 0.001, 95%CI [4.5. 48.5]) with high specificity (92%) but lower sensitivity (56%).

Conclusion: The cut-off values for TT-TG distance at 13 mm and 20 mm both had advantages and disadvantages which supports the concept of using patient-individualised ratios. Patellar instability is associated with many radiological abnormalities demonstrated on MRI scans. Selection of the most appropriate measurement is dependent on the philosophy and preference of the treating clinician.

Keywords: Knee; Magnetic resonance imaging; Odds ratio; Patellar instability; Sensitivity; Tibial-tubercle trochlear groove.

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Conflict of interest statement

Declarations. Conflict of interest: All authors declare that they have no conflict of interest. Ethical approval: This was a retrospective case–control radiological study which did not require IRB/ethics committee approval.

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References

    1. Martin RK, Leland DP, Krych AJ, Dahm DL (2019) Treatment of first-time patellar dislocations and evaluation of risk factors for recurrent patellar instability. Sports Med Arthrosc Rev 27(4):130–135. https://doi.org/10.1097/JSA.0000000000000239 - DOI - PubMed
    1. Huntington LS, Webster KE, Devitt BM, Scanlon JP, Feller JA (2020) Factors associated with an increased risk of recurrence after a first-time patellar dislocation: a systematic review and meta-analysis. Am J Sports Med 48(10):2552–2562. https://doi.org/10.1177/0363546519888467 - DOI - PubMed
    1. Balcarek P, Oberthür S, Hopfensitz S, Frosch S, Walde TA, Wachowski MM, Schüttrumpf JP, Stürmer KM (2014) Which patellae are likely to redislocate? Knee Surg Sports Traumatol Arthrosc 22(10):2308–2314. https://doi.org/10.1007/s00167-013-2650-5 - DOI - PubMed
    1. Sanders TL, Pareek A, Hewett TE, Stuart MJ, Dahm DL, Krych AJ (2018) High rate of recurrent patellar dislocation in skeletally immature patients: a long-term population-based study. Knee Surg Sports Traumatol Arthrosc 26(4):1037–1043. https://doi.org/10.1007/s00167-017-4505-y - DOI - PubMed
    1. Johnson DS, Turner PG (2019) Management of the first-time lateral patellar dislocation. Knee 26(6):1161–1165. https://doi.org/10.1016/j.knee.2019.10.015 - DOI - PubMed

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