We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Individualizing the tibial tubercle to trochlear groove distance to patient specific anatomy improves sensitivity for recurrent instability.
- Authors
Heidenreich, Mark J.; Sanders, Thomas L.; Hevesi, Mario; Johnson, Nicholas R.; Wu, Isabella T.; Camp, Christopher L.; Dahm, Diane L.; Krych, Aaron J.
- Abstract
<bold>Purpose: </bold>An initial episode of patellar instability poses a treatment challenge given the absence of a valid, reproducible, and universally applicable predictor of recurrence. Recently, a series of patellar instability ratios (PIRs) were described. Each ratio consisted of the traditional tibial tubercle to trochlear groove (TT-TG) distance normalized to patient-specific measures. The purpose of this study was to investigate the reliability and validity of these novel measures.<bold>Methods: </bold>Eighty-seven patients experiencing a first-time lateral patellar dislocation were identified in a retrospective manner. Magnetic resonance imaging (MRI) studies obtained at the time of injury were reviewed. The TT-TG distance, patellar width (PW), trochlear width (TW), patellar length (PL), and trochlear length (TL) were obtained by two observers in a blinded, randomized fashion. Measurement reliability was assessed using intra-class correlation coefficients (ICCs). Patients were divided into those having a single dislocation (Group 1) and those experiencing recurrent instability (Group 2). The ability of the TT-TG distance and each PIR to predict recurrent instability was assessed by calculating odds ratios (ORs) with 95% confidence intervals (CIs). Sensitivity and specificity were also calculated for each measure.<bold>Results: </bold>Excellent inter-rater agreement was observed with ICCs > 0.75 for all patellofemoral joint measurements obtained on MRI. The TT-TG distance alone was predictive of recurrent patellar instability with an OR of 8.9 (p < 0.001). However, the isolated TT-TG distance had the lowest sensitivity at 25.6%. Among ratios, a TT-TG/PL ≥ 0.5 was the most predictive of recurrent instability with an ORs of 6.1 (p = < 0.001). A TT-TG/TL ≥ 0.8 was also predictive of recurrence (OR 4.9, p = 0.027) and had the highest sensitivity of any measure at 94.9%.<bold>Conclusion: </bold>The results of the current study support the reproducibility and predictive ability of PIRs. While a TT-TG ≥ 20 mm was the strongest predictor of recurrent patellar instability, it was a relatively insensitive measure. Sensitivity may be improved by normalizing the TT-TG distance to patient-specific axial and sagittal plane patellofemoral measurements on MRI. Ultimately, PIRs are reproducible measures that may serve as an additional tool when clinically assessing the unstable patellofemoral joint.<bold>Level Of Evidence: </bold>III.
- Subjects
TIBIA; JOINT hypermobility; PATELLA; PATELLA injuries; PATELLOFEMORAL joint; ANATOMICAL planes; MAGNETIC resonance imaging; ANATOMY; KNEE anatomy; JOINT dislocations; KNEE; RESEARCH evaluation; DISEASE relapse; RESEARCH bias; RETROSPECTIVE studies
- Publication
Knee Surgery, Sports Traumatology, Arthroscopy, 2018, Vol 26, Issue 9, p2858
- ISSN
0942-2056
- Publication type
journal article
- DOI
10.1007/s00167-017-4752-y