Physical activity in the first postoperative week in 132 knee arthroplasty patients randomized to 3 different analgesic regimens.

BACKGROUND: The aim of this study was to investigate whether objectively recorded physical activity in the first week after surgery in total knee arthroplasty patients differed between patients allocated to 3 different analgesic regimens. METHODS: A total of 132 total knee arthroplasty patients wore activity monitors 24 hours a day from day 1 after surgery for 6 consecutive days. The time mobilized (stepping/standing) and the number of steps were recorded. This study was a sub-study of a randomized controlled study comparing tapentadol extended-release (ER), oxycodone controlled-release (CR), or a non-opioid placebo analgesic regimen. RESULTS: The placebo group spent significantly more time mobilized than the tapentadol ER and the oxycodone CR groups (P = .016 and .042, respectively), but no statistically significant differences were found between the groups in the number of steps taken. The activity levels of patients in all groups increased in the first week after surgery. CONCLUSION: Patients in the non-opioid placebo group spent more time mobilized the first week after surgery than those in the tapentadol ER and the oxycodone CR groups, while the number of steps was not different between the groups.

Cementless unicompartmental knee arthroplasty results in higher pain levels compared to the cemented technique: a prospective register study.

PURPOSE: In recent years, the preferred fixation method for unicompartmental knee arthroplasty (UKA) has changed from cemented to cementless. The aim of this study was to compare patient-reported outcome measures (PROMs) from the cemented versus cementless techniques two- and twelve-months post-operation. METHODS: From 2015 to 2019, 187 cemented and 261 cementless UKAs were included based on an institutional registry. The Oxford Unicompartmental Knee System™ (Zimmer Biomet, Bridgend, United Kingdom) was used for all patients. Three experienced surgeons performed all procedures. Data were collected pre- and peroperatively, and at two- and twelve-months postoperatively. PROMs included pain (evaluated on a numeric rating scale [NRS] during activity and at rest), and knee function (evaluated with the disease-specific short form of the Knee injury and Osteoarthritis Outcome Score [KOOS-PS]). Patients also rated postoperative joint function (better, unchanged, uncertain or worse) and were asked, "based on your experience to date, would you go through the surgery again?". Duration of surgery was noted and revisions during the first post-operative year were evaluated. RESULTS: The cemented group reported significantly lower activity-related pain at both two- and twelve-month follow-up. This was also the case for pain at rest at twelve-month follow-up, and KOOS-PS at two-month follow-up. Duration of surgery (adjusted for surgeon differences) was eight minutes less on average with the cementless technique. Eleven prosthetic joint infections (PJIs) were found following the cementless fixation technique compared to three using the cemented implant. CONCLUSION: UKA cases with cemented implants had lower pain scores during activity two and twelve months after surgery compared with those who had cementless implants. Differences in favor of the cemented group were also found for pain at rest one year after surgery and for KOOS-PS two months after. Surgery was significantly shorter in duration in the cementless group, but a relatively high number of PJIs were found in that same group. LEVEL OF EVIDENCE: Level II.

Preoperative pain catastrophizing and postoperative pain after total knee arthroplasty: a prospective cohort study with one year follow-up.

BACKGROUND: Pain relief is likely to be the most important long-term outcome for patients undergoing total knee arthroplasty (TKA). However, research indicates that persistent pain (> 3 months) is a considerable problem, affecting up to 34 % of patients. Pain catastrophizing might contribute to acute and persistent pain experienced after surgery. The primary aim of the present study was to examine the association between preoperative pain catastrophizing and postoperative pain in patients undergoing TKA up to one year after surgery. Second, we wanted to investigate a possible shift in postoperative catastrophizing. METHODS: In this prospective cohort study, 71 TKA patients were included consecutively between January and June 2013. Pain was assessed with the Brief Pain Inventory (BPI) and the item "average pain" was used as the main outcome. Pain catastrophizing was measured by the Pain Catastrophizing Scale (PCS). Questionnaires were completed prior to surgery (baseline) and at two days, two weeks, eight weeks and one year postoperatively. RESULTS: Mean (SD) preoperative pain score was 5.4 (2.2), reduced to 2.9 (2.3) after eight weeks and 2.4 (2.4) after one year (p < 0.001). The overall median preoperative PCS score was 17.0 (7.8-28.3). The overall model estimated PCS mean score was 7.6 at eight weeks and 6.5 at one year follow-up. The results at eight weeks and one year follow-up were both significantly lower than the preoperative value (p < 0.001). The preoperative PCS score was not associated with the postoperative pain score (p = 0.942), while preoperative pain was a significant covariate in the mixed linear model (p < 0.001). CONCLUSIONS: No associations were found between preoperative pain catastrophizing and pain eight weeks or one year after surgery. The decrease in PCS-scores challenges evidence regarding the stability of pain catastrophizing. However, larger studies of psychological risk factors for pain after TKA are warranted.