Increased collection of patient-reported outcome measures (PROM) in registries enables international comparison of patient-centered outcomes after knee and hip replacement. We aimed to investigate 1) variations in PROM improvement, 2) the possible confounding factor of BMI, and 3) differences in comorbidity distributions between registries.

Registries affiliated with the International Society of Arthroplasty Registries (ISAR) or OECD membership countries were invited to report aggregate EQ-5D, OKS, OHS, HOOS-PS and KOOS-PS values. Eligible patients underwent primary total, unilateral knee or hip replacement for osteoarthritis within three years and had completed PROMs preoperatively and either 6 or 12 months postoperatively, excluding patients with subsequent revisions. For each PROM cohort, Chi-square tests were performed for BMI distributions across registries and 12 predefined PROM strata (male/female, age 20-64/65-74/>75, high or low preoperative PROM scores). Comorbidity distributions were reported for available comorbidity indexes.

Thirteen registries from 9 countries contributed data, n~130000 knee (range 140 to 79848) and n~113000 hip (range 137 to 85281). Mean EQ-5D index values (10 registries) ranged from 0.53 to 0.71 (knee) and 0.50 to 0.70 (hips) preoperatively and 0.78 to 0.85 (knee) and 0.83 to 0.87 (hip) postoperatively. Mean OKS (6 registries) ranged from 19.3 to 23.6 preoperatively and 36.2 to 41.2 postoperatively. Mean OHS (7 registries) ranged from 18.0 to 23.2 preoperatively and 39.8 to 44.2 postoperatively. Four registries reported KOOS-PS and three reported HOOS-PS. Proportions of patients with BMI >30 ranged from 35 to 62% (10 knee registries) and 16 to 43% (11 hip registries). For both knee and hip registries, distributions of patients across six BMI categories differed significantly among registries (p30 were for patients in the youngest age groups (20 to 64 and 65 to 74 years) with the lowest baseline scores. Additionally, females with lowest preoperative PROM scores had highest BMI. These findings were echoed for the OHS and OKS cohorts. Proportions of patients with ASA scores ≥3 ranged from 7 to 42% (9 knee registries) and 6 to 35% (8 hip registries).

PROM-score improvement varies between international registries, which may be partially explained by differences in age, sex and preoperative scores. BMI and comorbidity may be relevant to adjust for.

Background

The duration and extent of postoperative wound leakage after joint arthroplasty in patients with or without a complicated course, like a prosthetic joint infection (PJI), is currently unknown. Adequate differentiation between normal postoperative wound leakage and wound leakage due to a postoperative PJI is important and prevents unnecessary surgical procedures. We investigated the association between postoperative wound leakage and development of PJI in patients who used a previously developed mobile wound care app.

Background

Treatment of staphylococcal prosthetic joint infection (PJI) usually consists of surgical debridement and prolonged rifampicin combination therapy. Tailored antimicrobial treatment alternatives are needed due to frequent side effects and drug-drug interactions with rifampicin combination therapy. We aimed to assess the effectiveness of several alternative antibiotic strategies in patients with staphylococcal PJI.

Aims

Current antibiotic treatment strategies for prosthetic joint infection (PJI) are based mostly on observational retrospective studies. High-quality data from prospective cohorts using identical treatment strategies may improve current clinical practice. We developed a regional network of collaborating hospitals and established a uniform treatment protocol. Data from all patients diagnosed with a PJI are prospectively registered in a an online database. With this quality registry we aim to study the outcome of antibiotic and surgical strategies while adhering to a pre-established treatment protocol.

Aim

Early discharge of patients after joint arthroplasty leaves patients responsible for monitoring their postoperative wound by themselves. This might result in a delayed presentation of postoperative complications. The use of a mobile woundcare app by patients after arthroplasty might result in (1) earlier report of complications, (2) an increase in patient satisfaction and (3) insight in the incidence and duration of postoperative wound leakage. Therefore, the ease of use and perceived usefulness of using a postoperative mobile woundcare app in patients after joint arthroplasty was investigated.

Computer navigation has been introduced as an adjunct to Total Knee Arthroplasty (TKA) to assure precision positioning, accurate bone resection and optimal component alignment. Using Computer Assisted Navigation in TKA was a hotly debated issue in United States and elsewhere. Although Computer Navigation has progressed from the 1st generation to the current 3rd generation system, there are still no clearly tangible, apparent long term clinical benefits.

There is some evidence that using Computer Assisted Surgery may lower the incidence of malalignment of mechanical limb axis compared to conventional component placement methods, but it is unclear whether this marginal benefit will translate to concrete positive long term outcomes. AAHKS survey results indicated that the majority of Orthopedic Surgeons were not using computer navigated surgical techniques. The implementation of CAS met with so many hurdles and obstacles because its approach consumes more time and a long learning curve, which translates to added cost and complexity. It is also labor and equipment intensive but only increases accuracy in the “right” hands. Lack of popularity for CAS has induced the innovation of Patient Specific Jigs which has been proven to be extremely accurate, efficient with respect to time and allows surgeons to navigate the operation prior to the procedure.

Since CAS remains unpopular in the US, it would be even less popular in Asia for the obvious reasons of high cost, lack of experts to handle technical difficulties, lack of publicity, and the paucity of beneficial expert testimonies. The “Better, Cheaper, Faster” culture is fully ingrained in the minds of most Asian Arthroplasty surgeons and CAS would seem to only fulfill the “Better”, but not the “Cheaper and Faster” expectations in most hands.

The mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component. This would reduce the contact stresses and wear which in turn may have a positive effect on the fixation of the prosthesis to the bone and thereby decreases the risk for loosening. The aim of this prospective randomized study was to evaluate early migration of the tibial component and kinematics of a mobile-bearing and fixed-bearing total knee prosthesis of the same single-radius design.

According to a prospective randomized protocol 20 Triathlon single-radius posterior- stabilized knee prostheses were implanted (9 mobile-bearing and 11 fixed-bearing). Fluoroscopy and roentgen stereophotogrammetric analysis were performed 6 and 12 months post-operatively.

The 1 year post-operative roentgen stereophotogrammetric analysis results showed considerable early migrations in 3 mobile-bearing patients and 1 fixed-bearing patient. The range of knee flexion was the same for the mobile-bearing and fixed- bearing group. The mobile insert was following the femoral component during motion.

This study showed no apparent distinction in early migration and kinematics between mobile-bearing and fixed-bearing single-radius total knee prostheses. Des- pite the mobile insert was following the femoral component during motion, and therefore performed as intended, no kinematic advantages of the mobile-bearing total knee prosthesis were seen. It is concluded that a mobile insert in single-radius total knee prostheses is redundant and will not lead to additional benefits.