Claudia S. Leichtenberg

Outcome of total hip arthroplasty, but not of total knee arthroplasty, is related to the preoperative radiographic severity of osteoarthritis: A prospective cohort study of 573 patients

Background and purpose — There is no consensus on the impact of radiographic severity of hip and knee osteoarthritis (OA) on the clinical outcome of total hip arthroplasty (THA) and total knee arthroplasty (TKA). We assessed whether preoperative radiographic severity of OA is related to improvements in functioning, pain, and health-related quality of life (HRQoL) 1 year after THA or TKA. Patients and methods — This prospective cohort study included 302 THA patients and 271 TKA patients with hip or knee OA. In the THA patients, preoperatively 26% had mild OA and 74% had severe OA; in the TKA patients, preoperatively 27% had mild OA and 73% had severe OA. Radiographic severity was determined according to the Kellgren and Lawrence (KL) classification. Clinical assessments preoperatively and 1 year postoperatively included: sociodemographic characteristics and patient-reported outcomes (PROMs): Oxford hip/knee score, hip/knee injury and osteoarthritis outcome score (HOOS/KOOS), SF36, and EQ5D. Change scores of PROMs were compared with mild OA (KL 0–2) and severe OA (KL 3–4) using a multivariate linear regression model. Results — Adjusted for sex, age, preoperative scores, BMI, and Charnley score, radiographic severity of OA in THA was associated with improvement in HOOS “Activities of daily living”, “Pain”, and “Symptoms”, and SF36 physical component summary (“PCS”) scale. In TKA, we found no such associations. Interpretation — The decrease in pain and improvement in function in THA patients, but not in TKA patients, was positively associated with the preoperative radiographic severity of OA.

Determinants of return to work 12 months after total hip and knee arthroplasty

Introduction A substantial number of patients undergoing total hip or knee arthroplasty (THA or TKA) do not or only partially return to work. This study aimed to identify differences in determinants of return to work in THA and TKA. Methods We conducted a prospective, observational study of working patients aged <65 years undergoing THA or TKA for osteoarthritis. The primary outcome was full versus partial or no return to work 12 months postoperatively. Factors analysed included preoperative sociodemographic and work characteristics, alongside the Hip Disability and Osteoarthritis Outcome Score (HOOS)/Knee Injury and Osteoarthritis Outcome Score (KOOS), and Oxford Hip and Knee Scores. Results Of 67 THA and 56 TKA patients, 9 (13%) and 10 (19%), respectively, returned partially and 5 (7%) and 6 (11%), respectively, did not return to work 1 year postoperatively. Preoperative factors associated with partial or no return to work in THA patients were self-employment, absence from work and a better HOOS Activities of Daily Living (ADL) subscale score, whereas only work absence was relevant in TKA patients. Type of surgery modified the impact of ADL scores on return to work. Conclusions In both THA and TKA, absence from work affected return to work, whereas self-employment and better preoperative ADL subscale scores were also associated in THA patients. The impact of ADL scores on return to work was modified by type of surgery. These results suggest that strategies aiming to influence modifiable factors should consider THA and TKA separately.

No associations between self-reported knee joint instability and radiographic features in knee osteoarthritis patients prior to Total Knee Arthroplasty: A cross-sectional analysis of the Longitudinal Leiden Orthopaedics Outcomes of Osteo-Arthritis study (LOAS) data

BACKGROUND To describe the prevalence of self-reported knee joint instability in patients with pre-surgery knee osteoarthritis (OA) and to explore the associations between self-reported knee joint instability and radiological features. METHODS A cross-sectional study including patients scheduled for primary Total Knee Arthroplasty (TKA). Self-reported knee instability was examined by questionnaire. Radiological features consisted of osteophyte formation and joint space narrowing (JSN), both scored on a 0 to three scale. Scores >1 are defined as substantial JSN or osteophyte formation. Regression analyses were provided to identify associations of radiological features with self-reported knee joint instability. RESULTS Two hundred and sixty-five patients (mean age 69years and 170 females) were included. Knee instability was reported by 192 patients (72%). Substantial osteophyte formation was present in 78 patients (41%) reporting and 33 patients (46%) not reporting knee joint instability. Substantial JSN was present in 137 (71%) and 53 patients (73%), respectively. Self-reported knee instability was not associated with JSN (relative to score 0, odds ratios (95% CI) of score 1, 2 and 3 were 0.87 (0.30-2.54), 0.98 (0.38-2.52), 0.68 (0.25-1.86), respectively) or osteophyte formation (relative to score 0, odds ratios (95% CI) of score 1, 2 and 3 were 0.77 (0.36-1.64), 0.69 (0.23-1.45), 0.89 (0.16-4.93), respectively). Stratified analysis for pain, age and BMI showed no associations between self-reported knee joint instability and radiological features. CONCLUSION Self-reported knee joint instability is not associated with JSN or osteophyte formation.

SAT0505 Self-reported knee instability associated with pain and activity limitations prior and one year after total knee arthroplasty in patients with knee osteoarthritis

Background Sixty to 80% of the patients with knee osteoarthritis (OA) reported self-reported knee joint instability, which was associated with pain and activity limitations. One previous randomized control trial described the prevalence of retained self-reported knee joint instability after total knee arthroplasty (TKA) (32%). To better understand self-reported knee joint instability in usual care there is a need to replicate and extend the results. Objectives The aims of the study were to determine (i) the prevalence of self-reported knee instability prior and one year after TKA, (ii) the associations between self-reported knee instability, pain, activity limitations and quality of life prior and one year after TKA, (iii) the course of self-reported knee instability over time and (iv) the associations between retained knee instability, pain, activity limitations and quality of life. Methods Consecutive patients with knee OA undergoing primary TKA, extracted from the Longitudinal Leiden Orthopaedics and Outcomes of OsteoArthritis Study (LOAS Study), were included. Self-reported knee joint instability and the Knee injury and Osteoarthritis Outcome Score (KOOS) Pain, Activity Daily Living (ADL) and QoL subscales (0–100; worst-best) were assessed by questionnaires prior and one year after surgery. Multivariable regression analyses were performed to determine associations between knee joint instability, pain, activity limitations and quality of life, adjusted for potential confounders including age, sex, comorbidities, physical activity and preoperative frailty. Results 908 patients were included of which 649 patients (72%) reported preoperative knee joint instability (mean age 67 years (SD8.6), 453 females (70%)) and 187 patients (21%) postoperative knee joint instability. Preoperative knee joint instability was associated with preoperative KOOS Pain (B-7.2;95% CI-10.9–3.5) and ADL (B3.8;95% CI-7.5–0.09), but not QoL (B-0.4;95% CI-2.1–1.2). In addition, postoperative knee joint instability was associated with postoperative KOOS Pain (B-13.5;95% CI-17.0–10.0), ADL (B-15.1,95% CI-18.4–11.8) and QoL (B-11.0;95% CI-13.5–8.5). Among the patients with preoperative self-reported knee joint instability, 165 patients (25%) retained knee instability and among the patients with no preoperative self-reported knee joint instability, 22 (8%) developed knee instability one year after surgery. After adjusting for baseline scores and potential confounders, retained knee joint instability was associated with postoperative KOOS Pain (B-19.6;95% CI-30.9–8.3), ADL (B-16.5;95% CI-27.0–5.9) and QoL (B-13.0;95% CI-17.9–8.1). Conclusions In usual care, knee joint instability is prevalent one year after TKA (21%). Reported knee joint instability is associated with more pain, worse physical function (pre- and postoperatively) and worse Qol postoperatively. Besides, retained knee joint instability was associated with worse pain, physical function and QoL. This emphasizes the importance of further research into the genesis of pre- and postoperative knee joint instability. Acknowledgements The study was funded by the Dutch Arthritis Foundation (DAF). Disclosure of Interest None declared

AB0844 Determinants of Returning to Work 12 Months After Total Joint Surgery: Differences Between Total Hip Arthroplasty and Total Knee Arthroplasty

Background The majority of the patients undergoing Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) returns to work postoperatively, but the absolute number of patients who do not return to work remains substantial. Little is known about factors limiting return to work1, Objectives To identify factors related to return to work after THA and TKA one year postoperatively. Methods This one-year prospective cohort study included patients who were assessed preoperatively and one-year postoperatively, aged 65 years or younger, and who provided information on their work status. Assessments included a questionnaire and/or telephone interview on work status. The outcome of return to work was divided into full return to work vs. partial or no return to work. Potential determinants included the following preoperative characteristics: physical hip/knee-job demands (classified into light, medium or heavy), the amount of working hours a week, self-employement, sick leave duration, granted disability benefits, presence of work adaptions and expectations of returning to work. Logistic regression analyses were employed to determine factors associated partial/no return to work in all patients, controlling for type of surgery (THA or TKA). Results Sixty-seven THA patients (mean age 56 years; SD 6.6, 33 females (49%)) and 56 TKA patients (mean age 56 years; SD 5.7, 31 females (55%)) were included. The mean amount of work hours a week preoperatively was 32 hours (SD 12.5) in THA patients and 31 hours (SD 12.3) in TKA patients. 53/67 THA patients (79%) and 40/56 TKA patients (71%) returned to work fully one-year post-operatively (same mean amount of work hours), whereas 5/67 THA patients (7%) and 7/56 TKA patients (13%) did not return to work at all and 9/67 THA patients (13%) and 9/56 TKA patients (16%) returned to work but less hours than preoperatively (mean decrease of work hours per week -17 hours (SD 11.5, P=0.002) in THA and -16 hours (SD 12.4, P=0.005) in TKA) The THA patients who returned to work partially or not had a lower educational level (P=0.006), were more often self-employed (P=0.009) and were more often absent from work due to hip complaints preoperatively than those fully returning to work (P=0.002). In the TKA group of patients there were no significant differences in characteristics of patients returning to work fully or not. In the multivariable logistic regression analyses, being self-employed (OR 7.4, 95%, CI 1.5-35.8), preoperative absence from work (OR 10.8, 95% CI 2.8-4.8) and working more hours preoperatively (OR 1.03, 95% CI 0.99-1.1) were factors significantly associated with partial/no return to work. Conclusions Self-employment, working more hours and being absent from work preoperatively remained determinants for partial/no return to work after correcting for type of prothesis. These findings underline the need to study return to work after THA and TKA separately. References C.Tilbury, et al., Return to work after total hip and knee arthroplasty: a systematic review. Rheumatology. (Oxford) 53(3), 512 (2014). Acknowledgements This study was funded by the Anna Fonds/NOREF Disclosure of Interest None declared

THU0437 Return to Work after Total Hip and Knee Arthroplasty: Results from A Prospective Cohort Study

Background A substantial proportion of patients undergoing Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) is of working age at the time of surgery. Although it is found that the majority of working patients return to work after surgery, the literature on duration until return to work and the impact of surgery on the amount of working hours in patients undergoing THA or TKA is scanty. Objectives The aim of this study was to measure duration until return to work and the impact of surgery on working hours in patients undergoing THA or TKA. Methods This study on work was part of a prospective cohort study on the outcomes of THA and TKA surgeries. This study included patients under 65 years of age, undergoing THA or TKA, who provided information on their work status before and one year after surgery. Assessments included a questionnaire on work status (yes/no), working hours per week and time to return to work. Comparisons of working hours before and after surgery were done with the Wilcoxon signed-rank test. Results Seventy-five of 122 THA (62%) and 70 of 120 TKA patients (59%) who were under 65 years had a paid job before surgery. The mean numbers of working hours per week were 32.3 (SD 13.4) in the THA group and 31.0 (SD 12.6) in the TKA group. Absence of work in relation to hip-or knee complaints during the year before surgery was reported by 19 (25%) and 19 (27%) of the employed patients with THA and TKA, respectively. The employment rates one year postoperatively were 66/75 (88%) after THA and 60/70 (86%) after TKA. The mean time to return to work was 12.5 (SD 7.5) and 12.9 (SD 7.8) weeks after THA and TKA, respectively. After 1 year, 17/66 (30%) of the patients with THA and 19/60 (32%) of patients with TKA worked less hours postoperatively as compared to preoperatively. In these patients, the number of working hours decreased significantly, with a mean difference of -14.4 hours (95% CI -19.5; -9.8) in the THA group and of -14.7 hours (95% CI -20.7; -9.4) in the TKA group (both p=0.002, Wilcoxon signed-rank test). Conclusions The majority of patients who had a paid job before surgery returned to work after THA and TKA, after approximately 12 weeks. Thirty % of the patients who returned to work, worked less hours than preoperatively. Given the increasing numbers of working patients undergoing THA or TKA more research into patients who do not return or decrease their working hours is needed. References Tilbury C. et al. Rheumatology 2013 Nov 23. [Epub ahead of print] Kuijer PP et al. J Occup Rehabil 2009;19(4):375-381. Kievit A.J. et al. Journal of Arthroplasty 2014; 10.1016 Acknowledgements Special thanks to the Annafonds|NOREF for their financial support. Disclosure of Interest : C. Tilbury Grant/research support: Anna Fonds/NOREF, C. Leichtenberg: None declared, R. Tordoir: None declared, M. Holtslag: None declared, S. Verdegaal: None declared, R. Nelissen: None declared, T. Vliet Vlieland: None declared DOI 10.1136/annrheumdis-2014-eular.2940