Ceramic Coating in Cemented Primary Total Knee Arthroplasty is Not Associated With Decreased Risk of Revision due to Early Prosthetic Joint Infection.

BACKGROUND: Prosthetic joint infection (PJI) is one of the most frequent and devastating causes of short-term revision total knee arthroplasty (TKA). In vitro evidence suggests ceramic surfaces demonstrate resistance to biofilm, but the clinical effect of bearing surface modifications on the risk of PJI remains unclear. This premier registry-based study examines the influence of ceramic bearing surface coatings on the outcome in cemented primary TKA. METHODS: In total, 117,660 cemented primary TKAs in patients with primary osteoarthritis recorded in the German arthroplasty registry since 2012 were followed up for a maximum of 3 years. The primary endpoint was risk of revision for PJI on ceramic coated and uncoated cobalt-chromium-molybdenum femoral components. Propensity score matching for age, gender, obesity, diabetes mellitus, depression and Elixhauser comorbidity index, and substratification on common design twins with and without coating was performed. RESULTS: In total, 4637 TKAs (85.1% female) with a ceramic-coated femoral component were identified, 42 had been revised for PJI and 122 for other reasons at 3 years. No survival advantage due to the risk of revision for PJI could be determined for ceramic-coated components. Revision for all other reasons demonstrated a significant higher rate for TKAs with ceramic-coated components. However, the results of this were confounded by a strong prevalence (20.7% vs 0.3%) of metal sensitivity in the ceramic-coated group. CONCLUSION: No evidence of reduced risk for PJI due to ceramic-coated implants in cemented primary TKA was found. Further analysis for revision reasons other than PJI is required.

Robotic-assisted knee arthroplasty: an evolution in progress. A concise review of the available systems and the data supporting them.

INTRODUCTION: A review of the data supporting robotic systems currently available is presented focussing on precision and reproducibility, radiological outcomes, clinical outcomes, and survivorship. MATERIALS AND METHODS: Scientific literature published on robotic systems for knee arthroplasty was reviewed using the reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria were any study involving robotic-assisted UKA or TKA that reported precision of implant positioning or functional outcomes or range of motion or survivorship, including cadaveric or dry bone studies with a minimum of 6-month follow-up. RESULTS: Thirty-nine studies were identified for robotic-assisted unicompartmental knee arthroplasty, and 24 studies for robotic-assisted total knee arthroplasty. Those that reported on radiological outcomes or cadaver studies consistently demonstrated improved precision with the use of robotic systems irrespective of the system. PROMS and survival data demonstrated equivalent short-term results. However, many studies reported outcomes inconsistently and few had long-term clinical follow-up or survivorship data. CONCLUSIONS: This review adds to the body of evidence supporting improved precision and reproducibility with robotic assistance in knee arthroplasty. Despite intensive funding of research into robotic knee systems, there remains considerable heterogeneity in exposure and outcome analysis and few quality long-term studies demonstrating translation to better clinical outcomes and implant survivorship.

Short versus conventional stem in cementless total hip arthroplasty : An evidence-based approach with registry data of mid-term survival.

BACKGROUND: Short-stemmed total hip arthroplasty (THA) is well established and gaining popularity in Germany. The perception that short stems may predispose to primary instability in the femur has resulted in a more thorough follow-up of younger patient cohorts than the typical uncemented THA population. To address this issue, an evidence-based approach is presented for a retrospective mid-term survival analysis of a large registry-based cohort in primary cementless THA comparing short stems with a matched group of conventional stems. MATERIAL AND METHODS: Propensity score matching (PSM, see Infobox 1) was used on 131,580 primary cementless THAs fulfilling the inclusion criteria performed between November 2012 and September 2019 and the cumulative probability of revision (CPR) of short and conventional stems for any reason, for reasons excluding prosthetic joint infection (PJI), and due to PJI were compared. RESULTS: After PSM at 1:1 balanced groups of 17,526 short stems and of 17,526 conventional stems were achieved demonstrating no significant difference for CPR for any reason and for reasons excluding PJI. Matched CPR for any reason was 2.9% (95% confidence interval, CI, 2.4-3.5%) 5 years after primary THA in the short stem and 3.1% (95% CI 2.7-3.4%) in the conventional stem group. The CPR excluding PJI was 2.2% (95% CI 1.7-2.7%) vs. 2.1% (95% CI 1.8-2.4%). In contrast, the incidence of PJI was statistically significant lower for short stems. CONCLUSION: For the considered period, there was no statistically significant survival difference in uncemented THA between comparison groups but a lower incidence for PJI in short-stem THA. Further analyses of registry data are required to rule out range of indications and late mechanical failure of short stems.

Anatomical site of radiographic degeneration is an independent variable influencing outcome of total knee arthroplasty.

OBJECTIVES: We aimed to determine whether the site of anatomical degenerative change could be identified as an independent risk factor influencing clinical outcome of total knee arthroplasty (TKA) 12 months postoperatively. METHODS: We compared preoperative, postoperative and the change observed in Oxford Knee Score (OKS) amongst TKA patients categorised as primarily medial, lateral or patellofemoral osteoarthritis (PFJOA). Multivariable regression analysis was conducted on 434 consecutive knees in 333 patients, adjusting for sex, age and body mass index (BMI). RESULTS: Adjusted estimates showed that preoperatively, patients with medial and lateral osteoarthritis (OA) had a lower mean OKS of 2.1 (p â€‹= â€‹0.049) and 2.3 (p â€‹= â€‹0.056) points respectively, while those with PFJOA had mean scores 2.7 points higher (p â€‹= â€‹0.062). There was no statistically significant difference between compartments in absolute postoperative OKS. The greatest improvement of 30.1 points (95% confidence interval (CI) 16.9-36.0, p â€‹= â€‹0.012) in OKS was observed for those with lateral OA, followed by 28.9 points (95% CI 16.7-35.3, p â€‹= â€‹0.049) for those with medial OA. The improvement observed postoperatively in patients with PFJOA was less than that observed for the average of the cohort at 24.5 (95% CI 11.5-29.7, p â€‹= â€‹0.088). CONCLUSIONS: The site of compartmental involvement in knee OA is an independent factor influencing clinical outcome of TKA. With arthroplasty registry adoption of patient-reported outcome measures (PROMs), this study supports precise anatomical categorisation of knee OA in outcome studies. LEVEL OF EVIDENCE: Level III, Retrospective consecutive clinical study.

Post-radiosynovectomy imaging of Er-169 using scintigraphy and autoradiography.

Currently, there is no protocol for the detection of intra-articular distribution of Er-169 citrate after radiosynovectomy. We propose post-therapeutic imaging using scintigraphy and cobalt-57 pen-marker autoradiography. This technique evaluates the efficacy of the radiosynovectomy and patient safety and could be utilized for dosimetric protocol.

Chondrocyte apoptosis in response to dislocation of the hip in the rat model.

BACKGROUND: Joint dislocation is a traumatic event that can lead to osteoarthritis. The purpose of this paper is to study cartilage changes following prolonged joint dislocation for 1, 2 or 8 h. METHODS: Sprague-Dawley rats (n = 27) were used in this study. Surgical dislocation of the hip under anaesthesia was carried out on the animals. The joints remained dislocated for 1, 2 or 8 h. The joints were subsequently harvested and terminal deoxnucleotidyl transferase-mediated dUTP nick-end labelling testing was carried out to show chondrocyte apoptosis in the femoral head and acetabulum. Using this test, the apoptotic index, which is the proportion of apoptotic chondrocytes to total number of chondrocytes, was calculated. A comparison of apoptotic indices was made among the three groups. RESULTS: The mean apoptotic indices for the femoral head for the 1-, 2- and 8-h groups were 0.065 +/- 0.025, 0.162 +/- 0.031 and 0.201 +/- 0.030, respectively. There was a significant difference (P < 0.05) in the mean apoptotic indices between each of the three groups. For the acetabulum, the mean apoptotic indices were 0.046 +/- 0.012, 0.051 +/- 0.023 and 0.057 +/- 0.031 for the 1-, 2- and 8-h groups, respectively. There was no significant difference (P > 0.05) between each of the three groups. CONCLUSIONS: Dislocation of a joint causes chondrocyte apoptosis. There is a progressive increase in the apoptotic index with prolonged dislocation of the rat hip.

A comparison of bone tunnel measurements made using computed tomography and digital plain radiography after anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to compare measurements of bone tunnel enlargement after anterior cruciate ligament (ACL) reconstruction using digital plain radiography and computed tomography (CT). TYPE OF STUDY: Within-subjects comparison of 2 imaging techniques. METHODS: Twenty-two patients who had undergone primary ACL reconstruction had anteroposterior and lateral digital plain radiographs and a CT scan of their operated knee 12 months after surgery. Using digital calipers, the sclerotic margins of each tunnel were measured at the widest point in each plane. Measurements were corrected for magnification and expressed as a percentage change in tunnel width compared with the size of the drill bit used at surgery. RESULTS: In all but 1 instance, bone tunnels seen on CT were also seen on the corresponding digital radiograph. In the single incidence in which a bone tunnel was identified on the CT scan but not on the radiograph, the tunnel had the smallest diameter of the group and had decreased since surgery by 30%. There was no difference between the group-averaged CT and radiographic measurements for the tibia, but femoral tunnel radiographic measurements were clearly larger than CT, particularly for the anteroposterior view (P < .001). Moderate discrepancy was noted between individual radiograph and CT measurements. CONCLUSIONS: Digital plain radiography appears to be satisfactory for detecting bone tunnel enlargement following ACL reconstruction. Thus it may offer a time- and cost-effective means for monitoring this phenomenon. LEVEL OF EVIDENCE: Level I.

Anterior cruciate ligament reconstruction in females: a comparison of hamstring tendon and patellar tendon autografts.

This study compared hamstring (HS) and patellar tendon (PT) anterior cruciate ligament (ACL) reconstruction in females. Sixty-five patients (43 HS, 22 PT) were evaluated at a mean 3.8-year postoperatively. Evaluation included IKDC 2000, SF-36, Cincinnati sports activity scores, anterior knee pain (AKP), kneeling pain, range of motion and anterior knee laxity. One PT patient sustained a traumatic graft rupture. There were no differences between the two grafts in terms of anterior knee laxity or IKDC scores. The HS group had higher sports activity scores and higher scores on the Physical Functioning and General Health subscales of the SF-36. Despite no difference in AKP, there was greater kneeling pain in the PT patients, who also had greater extension deficits. Both HS and PT are satisfactory ACL grafts in females, but HS grafts were associated with less morbidity, greater return to preinjury level of activity and higher quality of life scores.