Interrater Agreement of an Arthroscopic Anterior Cruciate Ligament Tear Classification System

Abstract

Background: Anterior cruciate ligament (ACL) rupture is the most common ligament injury treated surgically by orthopaedic surgeons. The gold standard for the treatment of the majority of primary ACL tears is ACL reconstruction. However, novel methods of repair, such as bridge-enhanced ACL repair (BEAR), are currently being investigated as alternatives to reconstruction. To assess patients for midsubstance repair suitability, clarify the prognostic implications of injury location and damage, and evaluate the results of a repair technique, it is important to have a baseline classification system or grading scale that is reproducible across surgeons, particularly for multicenter collaboration. Currently, no such system or scale exists.

Purpose: To develop an arthroscopic ACL tear classification system and to evaluate its interobserver reliability.

Study design: Cohort study (diagnosis); Level of evidence, 3.

Methods: Eleven fellowship-trained orthopaedic surgeon investigators reviewed 75 video clips containing arthroscopic evaluation of a torn ACL and then completed the 6-question ACL Pathology Evaluation Form. Agreement statistics including exact agreement, Fleiss κ, Gwet agreement coefficient 1 (AC1), and Gwet AC2 were then calculated to assess interobserver reliability.

Results: In aggregate, the multiple assessments of observer reproducibility revealed that surgeon participants in this study, when evaluating the same injury, agreed roughly 80% of the time on whether (1) at least 50% of the tibial footprint remained, (2) the remaining tibial stump was ≥10 mm, and (3) the injury was therefore reparable using the BEAR procedure. Participants also agreed roughly 60% of the time on exactly how many suturable bundles were available. These characteristics are believed to be most important, among those studied, in determining whether a torn ACL is amenable to midsubstance repair.

Conclusion: This study is the first of its kind to demonstrate the interobserver reliability of arthroscopic classification of ACL tears. We have demonstrated that this classification system, though not ideally reproducible, is reliable enough across surgeons at multiple institutions for use in multicenter studies.

Registration: NCT03776162 (ClinicalTrials.gov identifier).

Keywords: ACL reconstruction; ACL repair; ACL tear; interrater agreement; midsubstance repair; reliability.

Conflict of interest statement

One or more of the authors has declared the following potential conflict of interest or source of funding: This project was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (grant R01 1R07131). C.L.C. has a family member who is employed by Smith & Nephew. L.D.F. has received consulting fees from Zimmer Biomet and hospitality payments from the Musculoskeletal Transplant Foundation. P.F. has received education payments from Arthrex. D.F. has received education payments from CDC Medical and Zimmer Biomet; consulting fees from Aastrom Biosciences, Ceterix, Conmed Linvatec, DePuy, Hyalex, KCRN, Mitek, MTF, Moximed, Smith & Nephew, Vericel, and Zimmer Biomet; nonconsulting fees from Smith & Nephew and Vericel; faculty speaking fees from Linvatec; and honoraria from Vericel. M.H. has received education payments from Arthrex, nonconsulting fees from Smith & Nephew, and hospitality payments from Kairos Surgical. P.B.I. has received consulting fees from Colgate Palmolive and GE HealthCare. C.C.K. has received grant support from DJO, education payments from CDC Medical, consulting fees from Zimmer Biomet, and nonconsulting fees from Arthrex. B.D.O. has received consulting fees from Conmed/MTF, DePuy/Medical Device Business Services, Linvatec, Musculoskeletal Transplant Foundation, and Rotation Medical; has received royalties from Conmed/MTF; has received honoraria from Vericel; and is a paid associate editor for The American Journal of Sports Medicine. P.S. has received education payments from Arthrex and Rock Medical, consulting fees from Arthrex and DJO, and nonconsulting fees from Arthrex. R.W. has stock/stock options in Responsive Arthroscopy. Y.-M.Y. has received education payments from Kairos Surgical and consulting fees from Smith & Nephew. K.P.S. has received research support from Smith & Nephew; has received consulting fees from Flexion Therapeutics, Mitek, the National Football League, Novopeds, and Samumed; has received hospitality payments from Biosense Webster and DePuy; and is on the scientific advisory board for Cytori. DJO provides braces for the ongoing BEAR-MOON study. 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.

© The Author(s) 2020.

Figures

Figure 1.

The ACL Pathology Evaluation Form. ACL, anterior cruciate ligament; BEAR, bridge-enhanced ACL repair.

Figure 2.

Representative arthroscopic images of ACL stumps depicting reparability, tibial stump length, proportion of tibial footprint remaining, and number of stumps capable of being incorporated with a stitch. (A) 100% agreement that ACL can be repaired using BEAR technique; (B) mixed agreement that ACL can be repaired using BEAR technique; (C) 100% agreement that ACL cannot be repaired using BEAR technique; (D) 100% agreement that tibial stump exceeds 1 cm; (E) mixed agreement regarding length of tibial stump; (F) 100% agreement that tibial stump length is 1 stump capable of holding a suture is present. ACL, anterior cruciate ligament; BEAR, bridge-enhanced ACL repair.