Arthroscopy - 2026-09-25 - Journal Article
Preoperative Sagittal Tibial Tubercle-Trochlear Groove Distance Predicts Postoperative Outcome in Patients Undergoing Combined Trochleoplasty and Medial Patellofemoral Ligament Reconstruction.
Schmidt S, Navas L, Zimmermann F, Oudeh AEN, Lattermann C, Balcarek P
Topics
Key Takeaway
In 101 patients undergoing combined MPFL reconstruction and deepening trochleoplasty for Dejour B–D dysplasia, higher preoperative sagittal TT-TG distance independently predicted better BPII 2.0 scores (β=0.91, p=0.037), lower pain, and superior function at mean 32.3-month follow-up.
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Summary
This retrospective study asked whether preoperative sagittal TT-TG (sTTTG) distance—measured on axial T2 MRI as the perpendicular offset between trochlear cartilage and tibial tubercle referenced to the posterior condylar axis—predicts outcomes after combined MPFL reconstruction and deepening trochleoplasty in Dejour B–D dysplasia. Multivariable regression adjusting for age, BMI, Caton-Deschamps index, Dejour grade, and axial TT-TG confirmed that higher sTTTG independently predicted better BPII 2.0 (β=0.91, p=0.037), lower pain (β=−0.11, p=0.044), and better function (β=0.096, p=0.011). Overall, 89% achieved MCID for BPII 2.0, though model explanatory power was low (adjusted R²=0.03–0.06).
Key Limitation
The adjusted R² of 0.03–0.06 means that despite statistical significance, sTTTG accounts for a clinically negligible proportion of outcome variance, limiting its standalone predictive utility.
Original Abstract
PURPOSE
To evaluate the association between the preoperative sagittal tibial tubercle-trochlear groove (sTTTG) distance and postoperative patient-reported outcomes after combined patellofemoral ligament reconstruction and deepening trochleoplasty in patients with recurrent lateral patellar instability and high-grade trochlear dysplasia.
METHODS
This retrospective study included patients who underwent combined medial patellofemoral ligament reconstruction and deepening trochleoplasty for recurrent lateral patellar instability with high-grade trochlear dysplasia (Dejour grade B-D) between 2016 and 2018. Eligibility required ≥2 documented patellar dislocations or persistent symptoms after ≥6 months of nonoperative treatment, high-grade trochlear dysplasia on magnetic resonance imaging, and a minimum follow-up of 18 months. The sTTTG distance was measured on preoperative axial T2-weighted magnetic resonance imaging sequences as the perpendicular offset between the trochlear cartilage and the tibial tubercle, referenced to the posterior condylar axis. Postoperative outcomes were assessed using the Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0) score, alongside numeric rating scales for pain levels and subjective knee function. Univariable and multivariable linear regression analyses were performed, adjusting for age, body mass index, Caton-Deschamps index, Dejour classification of trochlear dysplasia, and tibial tubercle-trochlear groove distance.
RESULTS
A total of 101 patients (29 men, 72 women; mean age 22.7 ± 6.6 years; body mass index 24.3 ± 4.9) were included with a mean follow-up of 32.3 ± 8.7 months (range 19-60). Univariable analysis showed that a higher preoperative sTTTG was significantly associated with improved postoperative subjective function (β = 0.088, P = .014), lower pain levels (β = -0.10, P = .048), and higher BPII 2.0 scores (β = 0.98, P = .019). These associations remained statistically significant after adjusting for confounding variables (function: β = 0.096, P = .011; pain: β = -0.11, P = .044; BPII 2.0: β = 0.91, P = .037). Based on a cohort-specific minimal clinically important difference analysis, 89% of patients achieved clinically meaningful improvement in BPII 2.0, 77% in pain, and 88% in function. The multivariable models exhibited moderate explanatory power, with adjusted R 2 values ranging from 0.03 to 0.06.
CONCLUSIONS
The preoperative sTTTG distance is significantly associated with postoperative patient-reported outcomes in individuals undergoing deepening trochleoplasty. Higher sTTTG values were associated with better functional recovery, reduced pain, and enhanced patellofemoral quality of life.
LEVEL OF EVIDENCE
Level IV, retrospective cohort study.