Personalized Strategies for Patellar Instability Treatment
Publication Title: Breaking down tibial tuberosity to trochlear groove distance into two components to enable patient-specific treatment strategies
Summary
- Question
- This study examined how tibial tuberosity to trochlear groove (TT-TG) distance, a key measurement in evaluating patellofemoral instability (PFI), can be divided into two distinct components: translational and rotational. The authors aimed to understand how these components independently contribute to TT-TG and differ between patients with recurrent PFI and control subjects.
- Why it Matters
- PFI, which can lead to pain and reduced mobility, is often assessed using TT-TG distance. However, TT-TG combines two factors: bone structure (translational component) and tibiofemoral rotation (rotational component), making it difficult to pinpoint the root cause of instability. Separating these components provides a more personalized approach to diagnosis and treatment, potentially improving surgical outcomes and patient care by tailoring interventions to specific anatomical issues.
- Methods
- The researchers analyzed computed tomography (CT) scans from 26 patients with recurrent PFI and 294 control knees. Using three-dimensional (3D) modeling, they placed anatomical landmarks on the femur and tibia to calculate TT-TG, separating it into translational (bone morphology-driven) and rotational (tibiofemoral rotation-driven) components. Statistical methods were used to compare these components between the two groups and assess their relationship.
- Key Findings
- Patients with PFI had significantly higher TT-TG distances (18.7 mm vs. 12.0 mm in controls), with the rotational component (5.3 mm vs. 1.0 mm) contributing more to the difference than the translational component (13.4 mm vs. 11.0 mm). There was no significant correlation between the two components, meaning elevated TT-TG could result from either or both factors. Additionally, tibiofemoral rotation strongly influenced the rotational component, with each degree of rotation adding approximately 0.5 mm to TT-TG.
- Implications
- These findings suggest that surgical and therapeutic strategies for PFI should be tailored to address either the translational or rotational component, or both, depending on the patient’s specific anatomy. For example, translational issues may benefit from tibial tuberosity osteotomies, while rotational problems may require derotational osteotomies or physical therapy targeting knee stabilizers. This personalized approach could enhance treatment precision and outcomes.
- Next Steps
John Fulkerson and Johannes Sieberer recommend further research into the variability of tibiofemoral rotation during imaging and its relationship with PFI. They also suggest developing standardized imaging protocols to reduce measurement errors and investigating how other metrics can complement TT-TG in assessing PFI. Furthermore, the authors emphasize the importance of 3-D imaging for understanding complex joint dysfunction. This is fairly new to the orthopedic surgery world and has important implications for improving patient care.
- Funding Information
- This research was supported by the National Institutes of Health (grants AG19069, AG18820, AG18947, and AG18832) and Yale University. Brooke McGinley was supported by an NIH Institutional Training Grant (T32 GM140972). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Full Citation
Sieberer J, Park N, Desroches S, Brennan K, Rancu A, McGinley B, Manafzadeh A, Segal N, Felson D, Tommasini S, Wiznia D, Fulkerson J. Breaking down tibial tuberosity to trochlear groove distance into two components to enable patient-specific treatment strategies. Journal Of ISAKOS Joint Disorders & Orthopaedic Sports Medicine 2025, 16: 101025. PMID: 41173215, PMCID: PMC12802969, DOI: 10.1016/j.jisako.2025.101025.
This AI-assisted summary has been reviewed and approved by at least one of the study's authors to ensure it accurately reflects the research.
Authors
Johannes M Sieberer, MSc, MS
First AuthorJohn Fulkerson, MD
Last AuthorProfessor of Orthopaedics & Rehabilitation
Additional Yale School of Medicine Authors
Other Authors
Research Themes
Concepts
- Patellofemoral instability patients;
- Intraclass correlation coefficient;
- TT-TG;
- Patellofemoral instability;
- Computed tomography;
- Multicenter Osteoarthritis Study;
- Treatment strategies;
- Selection of surgical methods;
- Cohort mean;
- Control CT scan;
- Patient-specific treatment strategies;
- Surgical decision-making;
- Tibiofemoral rotation;
- Mann-Whitney U test;
- Personalized treatment strategies;
- TT-TG measurements;
- Individual patient profiles;
- Statistically significant difference;
- Trochlear groove distance;
- No significant correlation;
- Surgical methods;
- CT scan;
- Patellar instability;
- Mann-Whitney;
- U test