The Rapidly Assessed Predictor of Intraoperative Damage (RAPID) Score: An In-Clinic Predictive Model for High-Grade Acetabular Chondrolabral Disruption.

Background: The preoperative assessment of cartilage lesions is critical to surgical planning and decision making. The accurate radiographic determination of acetabular cartilage damage has remained elusive for modern imaging modalities, including magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA). While risk factors have been individually described, no multivariable system exists for predicting high-grade cartilage damage.
Purpose: To determine the preoperative predictors of grade 3 to 4 acetabular labrum articular disruption (ALAD) lesions.
Study Design: Case-control study; Level of evidence, 3. Cohort study (diagnosis); Level of evidence, 1.
Methods: Retrievable radiographs were reviewed from primary hip arthroscopic procedures performed at 2 high-volume institutions between December 2007 and April 2017. The predictive value of demographic and radiographic factors for the intraoperative documentation of ALAD grade 3 to 4 damage was analyzed and entered into a multivariable model, and a statistically guided scoring system for the damage risk was created using the Akaike information criterion. The scoring system was then prospectively validated on 167 patients who underwent primary hip arthroscopy between April 2017 and February 2018.
Results: A total of 652 primary hip arthroscopic procedures in 614 patients (390 female, 224 male; mean age, 33.2 ± 12.5 years; mean body mass index, 26.9 ± 5.5 kg/m ² ) from 2007 to 2017 were analyzed. Male sex (odds ratio [OR], 3.11; P < .01), age ≥35 years (OR, 1.96; P < .01), cam morphology (alpha angle >55°) (OR, 2.96; P < .01), and Tönnis grade 1 to 2 (grade 1: OR, 4.14; P < .01, and grade 2: OR, 9.29; P < .01) were univariate risk factors for intraoperatively documented high-grade damage. A multivariable scoring system, the Rapidly Assessed Predictor of Intraoperative Damage (RAPID) score (0-5 points), was generated based on sex, Tönnis grade, and cam morphology. Patients with increasing RAPID scores had an increasing risk of damage, with a 10.5% risk for those with 0 points and an 88.0% risk for those with 5 points ( P < .01). The area under the curve was 0.75 for the study group and 0.76 for the validation group ( P = .94).
Conclusion: While preoperative MRI has diagnostic value for hip arthroscopic surgery, the RAPID score provides added benefit as a readily employable, in-clinic system for predicting high-grade cartilage damage. The discriminatory value of the RAPID score compares favorably with previous MRI and MRA studies. This information will help the clinician and patient plan for high-grade damage and identify potential targets for cartilage treatment.
Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: M.H. has received hospitality payments from DePuy. D.E.H. has received educational support from Arthrex and Smith & Nephew and hospitality payments from Desert Mountain Medical and Stryker. D.B.F.S. is a paid speaker/presenter for Smith & Nephew and is a paid consultant for Smith & Nephew, Genzyme, and TiGenix. B.A.L. receives royalties from Arthrex and VOT Systems, is a paid consultant for Arthrex, and is a paid speaker/presenter for the Canadian Orthopaedic Association and Smith & Nephew. A.J.K. receives research support from Aesculap/B. Braun, the Arthritis Foundation, Ceterix, and Histogenics; receives royalties from Arthrex; is a paid consultant for Arthrex, Vericel, and DePuy; and has received honoraria from Vericel and the Musculoskeletal Transplant Foundation. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.