Flexible versus standard intramedullary rod in posterior stabilized primary total knee arthroplasty: protocol for a randomized controlled trial.

BACKGROUND: In total knee arthroplasty (TKA) a flexible intramedullary rod can be used to account for sagittal bowing of the distal femur. Although patients report better post-operative functional outcome when the flexible rod was used, it is unknown how the use of the flexible rod affects the placement of the femoral TKA component, and how this relates to activities of daily living. It is expected that the use of the flexible rod will result in a more flexed femoral component, a larger patellar tendon moment arm, and consequently in better functional outcome. The goal of this study is to compare the flexible rod to the standard intramedullary rod in primary TKA in terms of fit of the TKA, functional outcome, and sizing of the femoral component. METHODS: A single-blind randomized controlled trial with two groups (flexible vs standard rod), with patients blinded for group allocation, and 2 years post-operative follow-up. The fit of the TKA is quantified by two parameters: (1) the flexion angle of the TKA in the sagittal plane and (2) the sagittal profile of the distal femur compared between the pre-operative bone and the TKA. Both parameters are calculated in 3D volume images obtained using fluoroscopy. Functional outcome will be measured using (1) the timed Get-up and Go test (2), the stair climbing test (3), knee power output, and (4) patient and clinician reported outcomes. Different parameters will be measured during the TKA procedure to account for the invisibility of cartilage in the 3D volumes and to study if the amount of bone removed during the procedure is affected by group allocation. DISCUSSION: The sagittal fit of TKA is not a standardized outcome measure. We discuss our choice of parameters to define the sagittal fit (i.e., flexion angle and sagittal profile), our choice for the parameters we measure during the TKA procedure to account for the lack of cartilage thickness in fluoroscopy, and our choice for the parameters to study if the amount of bone removed during the procedure is affected by group allocation. Lastly, we discuss the merits of this planned trial. TRIAL REGISTRATION: Netherlands Trial Register, 4888 , registered 30 March 2015. https://www.trialregister.nl/trial/4888.

Femoral prosthesis neck fracture following total hip arthroplasty - a systematic review.

PURPOSE: Head-neck modularity was introduced into total hip arthroplasty to provide more intraoperative surgical options. However, modularity led to new problems, such as trunnionosis and fractures of the femoral prosthesis neck. The purpose of this study was to identify risk factors for hip neck fractures and to provide recommendations to prevent damage and fractures of the neck. METHODS: A systematic review of the literature was performed according to the PRISMA guidelines. RESULTS: Thirty-three case studies were included. Methodologically, most included studies were of moderate or good quality. The 80 neck fractures included in the review took place, on average, 7 years after stem placement. Male gender, high body weight, obesity, previous revision surgery, mixing components from different manufacturers, use of long skirted heads, cobalt-chromium (large size) heads were identified as potential risk factors. CONCLUSION: Hip neck fractures occur on average 7 years after stem placement. The etiology of hip neck fractures is multifactorial. This review revealed several preventable implant- and surgeon-related risk factors.

Patients who underwent total hip or knee arthroplasty are more physically active than the general Dutch population.

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) bring relief of pain and functional disability to patients with end-stage osteoarthritis, and however, the literature on their impact on patients' level of physical activity (PA) is scarce. Cross-sectional study in patients who underwent THA/TKA surgery in the preceding 6-22 months and a random sample of persons aged >40 years from the Dutch general population, participating in a national survey. PA in minutes per week (min/week) and adherence to the Dutch recommendation for PA (NNGB yes/no) were measured by the short questionnaire to assess health-enhancing PA. Multivariable linear (total min/week) and logistic regression analyses (meeting recommendations PA), adjusting for confounders, were performed for THA and TKA separately. In total, 258 THA [62.3% female, aged 69.4 (9.1)] and 221 TKA [65.7% female, aged 69.5 (8.9)] patients and 4373 persons from the Dutch general population [51.4% female, aged 58.9 (11.6)] were included. The presence of THA was associated after adjusting for age, sex, BMI education and musculoskeletal comorbidities, with more total min/week spent on PA (THA 13.8% increase, 95% CI 1.6-27.6%), whilst both TJA groups were associated with adhering to NNGB (THA: OR 1.79, 95% CI 1.26-2.56; TKA: OR 1.73, 95% CI 1.20-2.51). As this study used questionnaires to compare the PA of THA/TKA patients to the general population, some recall and selection bias might have been induced. After surgery, overall, TJA patients are more likely to adhere NNGB than a representative sample of persons >40 years from the Dutch general population.

The association between comorbidities and pain, physical function and quality of life following hip and knee arthroplasty.

The aim of the study was to examine the relationship between comorbidities and pain, physical function and health-related quality of life (HRQoL) after total hip arthroplasty (THA) and total knee arthroplasty (TKA). A cross-sectional retrospective survey was conducted including 19 specific comorbidities, administered in patients who underwent THA or TKA in the previous 7-22 months in one of 4 hospitals. Outcome measures included pain, physical functioning, and HRQoL. Of the 521 patients (281 THA and 240 TKA) included, 449 (86 %) had ≥1 comorbidities. The most frequently reported comorbidities (>15 %) were severe back pain; neck/shoulder pain; elbow, wrist or hand pain; hypertension; incontinence of urine; hearing impairment; vision impairment; and cancer. Only the prevalence of cancer was significantly different between THA (n = 38; 14 %) and TKA (n = 52; 22 %) (p = 0.01). The associations between a higher number of comorbidities and worse outcomes were stronger in THA than in TKA. In multivariate analyses including all comorbidities with a prevalence of >5 %, in THA dizziness in combination with falling and severe back pain, and in TKA dizziness in combination with falling, vision impairments, and elbow, wrist or hand pain was associated with worse outcomes in most of the analyses. A broad range of specific comorbidities needs to be taken into account with the interpretation of patients' health status after THA and TKA. More research including the ascertainment of comorbidities preoperatively is needed, but it is conceivable that in particular, the presence of dizziness with falling, pain in other joints, and vision impairments should be assessed and treated in order to decrease the chance of an unfavorable outcome.