Increased tibial tubercle-trochlear groove and patellar height indicate a higher risk of recurrent patellar dislocation following medial reefing

Abstract

Purpose Identifying anatomical risk factors on recurrent dislocation after medial reefing is important for deciding surgical treatment. The present study aimed to retrospectively analyze the preoperative magnetic resonance imaging (MRI)-based parameters of patients treated with medial reefing and whether these parameters lead to a higher risk of recurrent dislocation. Methods Fifty-five patients (18.6 ± 6.6 years) who underwent medial reefing after primary traumatic patellar dislocation (84% with medial patellofemoral ligament [MPFL] rupture) were included. Patients were followed up for at least 24 months postoperatively (3.8 ± 1.2 years) to assess the incidence of recurrent patellar dislocation. In patients without recurrent dislocation, the Kujala and subjective IKDC scores were assessed. Moreover, the tibial tubercle-trochlear groove (TT-TG), sulcus angle, patellar tilt, patellar shift, and lateral trochlea index (LTI) were measured. The patellar height was measured using the Caton-Dechamps (CDI), Blackburne-Peel (BPI), and Insall-Salvati index (ISI). The cohort was subclassified into two groups with and without recurrent dislocation. Differences between groups were analyzed with respect to the MRI parameters. Results Forty percent had a pathological sulcus angle of > 145°, 7.2% had an LTI of < 11°, 47.3% had a patellar tilt of > 20°, and 36.4% had a TT-TG of ≥ 16 mm. Increased patellar height was observed in 34.5, 65.5, and 34.5% of the patients as per CDI, BPI, and ISI, respectively. Nineteen (34.5%) patients suffered from recurrent dislocation. Compared with patients without recurrent dislocation, those with recurrent dislocation had a significantly lower LTI (p = 0.0467). All other parameters were not significantly different between the groups. Risk factor analysis showed higher odds ratios (OR > 2), although not statistically significant, for MPFL rupture (OR 2.05 [95% confidence interval 0.38–11.03], LTI (6.6 [0.6–68.1]), TT-TG (2.9 [0.9–9.2]), and patellar height according to ISI (2.3 [0.7–7.5]) and CDI (2.3 [0.7–7.5])). Patients without recurrent dislocation had a Kujala score of 93.7 ± 12.1 (42–100) points and an IKDC score of 90.6 ± 11.7 (55.2–100) points. Conclusion Anatomical, MRI-based parameters should be considered before indicating medial reefing. A ruptured MPFL, an LTI < 11°, a TT-TG ≥ 16 mm, a patellar tilt > 20 mm, and an increased patellar height according to ISI and CDI were found to be associated, although not significantly, with a higher risk (OR > 2) of recurrent patellar dislocation after medial reefing. Thorough preoperative analysis is crucial to reduce the risk of recurrent dislocation in young patient cohorts. Level of evidence Level IV

Trochlea dysplasia, increased TT-TG distance and patella alta are risk factors for developing first-time and recurrent patella dislocation: a systematic review

“…Fifteen studies found trochlear dysplasia to be a significant risk factor for recurrent PD (OR 2.53–18.945) and (hazard ratio (HR) 2.3–3.27) [2, 6, 14, 20, 30, 33, 37, 38, 41, 42, 55, 59, 60, 67, 73]. Three studies did not find a significant association to PD [1, 26, 57] (Table 1 and Appendix 3; Table 5).…”

Change of the cross-sectional area of vastus medialis oblique in patients with recurrent patellar dislocation treated by tibial tubercle transfer combined with medial patellofemoral ligament reconstruction on axial CT

“…In clinical work, many researchers agreed that TT-TG distance less than 20 was appropriate [ 34 ]. Researchers claimed that the increase in TT-TG distance would aggravate the lateral stress of patella in patients and even lead to the recurrence of patellar dislocation [ 35 ]. Tibial tubercle transfer reduced TT-TG distance by moving the tibial tubercle inward in response to the lateralization of the tibial tubercle relative to the femoral trochlear groove [ 36 ].…”

3D-printed individualized navigation template versus the fluoroscopic guide to defining the femoral tunnel for medial patellofemoral ligament reconstruction: A retrospective study

“…The sample size of this study was 60 cases, 30 cases in each of the 2 groups. Inclusion criteria: patients aged 18 to 45 years (2) more than 2 dislocations after the first dislocation; painful patellar instability symptoms or subluxation; positive patellar apprehension test; [14] excessive patellar tilt angle on computed tomography (CT) and MPFL tear on magnetic resonance imaging. Exclusion criteria: age < 18 years or more than 45 years; bony structural abnormalities: Insall-Salvati index ≥ 1.2, [15] tibial tuberosity-trochlear groove distance of ≥ 20 mm, [16] Severe Trochlear Dysplasia (Dejour type B, C, or D), [17] Femoral anteversion angle ≥ 25°, [18] and previous surgery on the affected knee, all performed by a surgically experienced chief surgeon.…”