Yoeri Bemelmans

Chapter 9 144 postoperative including the Dutch validated Oxford Knee Score (OKS; 12–60, 12 being the best outcome) [10], Western Ontario andMcMaster Universities Arthritis Index (WOMAC; 0–100, 100being thebest outcome) [29] and theEuro-Qol-5D(EQ-5D; 0–1, 1 indicates thebest healthstate) [3]. ExperiencedpainwasmeasuredbyaNumerical RatingScale (NRS, 0–10, 10 being ‘worst pain’). All PROMswereconductedprior to theoutpatient visit. Activemeasures of flexionandextensionweredeterminedusingadigital inclinometer (MicroFET5, Hoggan Health Industries, Salt LakeCity,USA)withahigh level of accuracy. TheRoMof theoperated leg was measured twice, and the average value was used [36, 37]. RoMwas obtained pre-, 1 and 6weeks postoperative. Statistical analysis All statistical analysis was done with use of SPSS version 17.0 for windows (Inc., Chicago, IL). Statistically significant differences between both groups were analysed with nonparametricMann–Whitney U test, since the group sizes were small. Chi-square test was used for categorical variables. P values were considered to be statistically significant at p ≤ 0.05 for all analysis. This study was carried out in an attempt to predict an appropriate sample size to design a full-scale research project. Aminimumpilot trial sample size per arm of 10 patients is appropriate [35]. Results No patients were lost to follow-up. At 6-week follow-up, all physical activity parameters were comparable between both groups (Fig. 1; Table 3). Looking at the preoperative activity levels and longitudinally also at the direct postoperative days (Fig. 1), groups were statistically comparable showing equal amounts of preoperative activity and matching recovery profiles in all activity parameters with no group difference (n.s.). Activity recovers steeply during the first 4 postoperative days and continues to improve towards the 6-week assessment when it remains belowpreoperative levels. As expected, the overall mean LoSwas statistically significant different ( p ≤ 0.000) in favour of theOS pathway. The ERP patients were discharged after a mean of 52:30 h (range, 25:12–97:12) compared to a mean discharge of 9:30 h (range, 8:20–12:06) in the OS pathway. Early mobilization was not different between both groups (n.s.). Patients mobilized within a mean of 4:06 h (range, 1:15–6:37) and 3:11 h (range, 2:10–4:22) for, respectively, the ERP and OS pathway. One patient in the ERP pathway was not able to mobilize <4 h postoperative due to loss of sensibility, and the first mobilization was postponed. At 6 weeks postoperatively, mean (±SD) PROMs improved within each pathway compared to preoperative values. No statistically significant or clinically relevant differences for the PROMs and RoM were found between both pathways (Table 4).