Single-Legged Hop Tests as Predictors of Self-Reported Knee Function in Nonoperatively Treated Individuals with Anterior Cruciate Ligament Injury

Grindem H, Logerstedt D, Eitzen I, Moksnes H, Axe M, Snyder-Mackler L, Engebretsen L, Risberg M. Am J Sports Med. Epub 2011 Aug 9  

The decision to advise operative versus nonoperative treatment in the anterior cruciate ligament (ACL) deficient patient is becoming more challenging. The standard of care across the world varies; in America immediate reconstruction is typical, while in many European countries an attempt at nonoperative care is the norm. The decision to recommend nonoperative care involves objective screening information, subjective reported function, and desired activity level post intervention. The goal of this investigation was to determine if any of the 4 typically utilized hop tests (single hop for distance, crossover hop for distance, triple hop for distance, or 6-m timed hop), which are used to provide objective measures of functional status, could predict knee reported function one-year post injury in 91 patients that elected nonoperative treatment (link to hop test descriptions). The average time between injury and hop testing was 74 ± 30 days because the clinic required patients to undergo five weeks of rehabilitation to ensure adequate hop performance, no knee effusion, and as a precursor for possible reconstruction. Only patients with no other intra-articular injuries (asymptomatic meniscal tears were permissible) and not returning to high-level cutting sports were considered for non-operative treatment limiting those that pursue nonoperative care to 44% of all ACL ruptures treated. Among the participants that elected nonoperative treatment the use of the single-limb hop for distance was the only significant predictor of future reported knee function (IKDC 2000). A cut off of 88% symmetry index on the single-limb hop test (jumping at least 88% of the distance with the injured limb as compared to the uninjured) predicted return to approximately normal knee function with 71.4% sensitivity and 71.7% specificity. Stacking the other hop tests with the single-limb hop for distance did not improve predictive value.

Nonoperative treatment for ACL rupture while growing in popularity does require proper assessment to determine if the outcome will be successful. This study demonstrates that the symmetry index for the single-limb hop for distance test can help predict knee function one year later. Furthermore, this study further validates this test as a screening tool for ACL operative decision making. However, this study was completed in an observational manner to their normal clinic guidelines thus it must be emphasized that while other authors (Hurd et al. Part 1, Part 2) have returned athletes to high level pivoting sports those in this study were recommended operative treatment. This may lead many patients to report relatively high function secondary to not returning to previous activities. Also they did not report their raw hop distances so it is unknown if their hop scores were approximately normal for age or gender and if the symmetry index was influenced by the patient hopping high or low distances.This may explain some of their false negative and positive results of the testing. Does anyone work in a clinic setting that does ACL screening or considers nonoperative care? If so any insights into situations where this has been a challenge? Any tools or ideas you like to employ in this decision making process?

Written by: Dustin Grooms

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Grindem H, Logerstedt D, Eitzen I, Moksnes H, Axe MJ, Snyder-Mackler L, Engebretsen L, & Risberg MA (2011). Single-legged hop tests as predictors of self-reported knee function in nonoperatively treated individuals with anterior cruciate ligament injury. The American Journal of Sports Medicine, 39 (11), 2347-54 PMID: 21828364