COMPARING QUANTIFICATION METHODOLOGIES FOR THE SINGLE LEG-HEEL RISE TEST IN PATIENTS FOLLOWING OPERATIVE AND NONOPERATIVE MANAGEMENT FOR ACHILLES TENDON RUPTURE

The Single Leg Heel Rise (SLHR) is commonly used to determine the functional status of patients following Achilles Tendon Rupture (ATR). The number of repetitions per limb is often not sufficient to quantify performance deficits, whereas peak heel rise height and total work may be more sensitive. Multiple methods exist to quantify performance variables during the SLHR including linear position transducers, video motion capture and mobile video technologies; however, these methodologies have not been directly compared in their quantification of SLHR performance following operative or non-operative management of Achilles Tendon rupture. Patients were retrospectively identified that were between the ages of 18–65, who had a complete ATR that was treated within three weeks of injury with either operative or non-operative management. The SLHR was completed to exhaustion with maximal, unilateral heel rises on a 10oangle board. A linear position transducer (LPT; GymAware, ACT, AUS) was anchored to the posterior calcaneus during the test. One sagittal plane camera (Ninox 125, Noraxon, AZ, USA) recorded for both the motion analysis data, which was post-processed in MyoVideo (MoCap; Noraxon, AZ, USA) and the Calf Raise App (APP; Hebert-Losier, 2020). Between limb and group differences in all variables were compared with a two-way ANOVA. Pearson correlations and Bland Altman plots (limits of agreement (LOA)) were completed on work and limb symmetry index (LSI) values. Twenty four patients (n=12 operative and non-operatively treated; 42.6 ± 12.3 years, 174.9 ± 8.0 cm, 92 ± 18.8 kg, 17 male, 7 female) completed the SLHR. Total SLHR repetitions were lower in the non-operative group when measured with MoCap and the APP (p<0.05) but not the LPT. Peak heel rise height was reduced on the affected limb regardless of group across all three methods (p<0.05). Total heel rise height over the test was greater in the operative group regardless of limb when measured with MoCap and APP (p<0.05) but not the LPT. While total work was reduced on the affected limb, and more so in the non-operative group, this did not reach the threshold for statistical significance. Strong, positive correlations were demonstrated between all devices for total work, with the highest between MoCap and the APP (r2= 0.997), followed by the LPT and APP (r2= 0.906) and MoCap and LPT (r2= 0.905; p<0.001 for all). Similarly strong correlations were demonstrated (r2= 0.781 – 0.990) across devices for work LSI. Agreement for LSI was acceptable between MoCap and App (−0.067 % (95%LOA −6.38–6.25%); However, limits of agreement were broader for total work across all devices, or between MoCap or APP and the LPT for LSI. The Calf Raise App represents a simple method for both patients and clinicians to quantify between-limb deficits following operative or non-operative management of ATR during the SLHR using readily available technology. While work and LSI values between video capture technologies agree, they are not interchangeable with those from LPTs due to wide limits of agreement despite strong correlations amongst all devices.