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Contains fulltext : 242805.pdf (Publisher’s version ) (Open Access) Background and purpose - From previous studies, we know that clinical outcomes of revision total knee arthroplasty (rTKA) differ among reasons for revision. Whether the prevalence of repeat rTKAs is different depending on the reason for index rTKA is unclear. Therefore, we (1) compared the repeat revision rates between the different reasons for index rTKA, and (2) evaluated whether the reason for repeat rTKA was the same as the reason for the index revision.Patients and methods - Patients (n = 8,978) who underwent an index rTKA between 2010 and 2018 as registered in the Dutch Arthroplasty Register were included. Reasons for revision, as reported by the surgeon, were categorized as: infection, loosening, malposition, instability, stiffness, patellar problems, and other. Competing risk analyses were performed to determine the cumulative repeat revision rates after an index rTKA for each reason for revision.Results - Overall, the cumulative repeat revision rate was 19% within 8 years after index rTKA. Patients revised for infection had the highest cumulative repeat revision rate (28%, 95% CI 25-32) within 8 years after index rTKA. The recurrence of the reason was more common than other reasons after index rTKA for infection (18%), instability (8%), stiffness (7%), and loosening (5%).Interpretation - Poorest outcomes were found for rTKA for infection: over 1 out of 4 infection rTKAs required another surgical intervention, mostly due to infection. Recurrence of other reasons for revision (instability, stiffness, and loosening) was also considerable. Our findings also emphasize the importance of a clear diagnosis before doing rTKA to avert second revision surgeries.

A cam deformity is proposed as a cause of idiopathic osteoarthritis. Increased subchondral bone mineral density (BMD) is associated with this degenerative process of osteoarthritis, and the patient’s activity level may contribute to it. Therefore, the correlation between activity level and subchondral BMD in subjects with cam deformity FAI was studied. In this study, 26 asymptomatic cam deformity subjects (Bump) were compared with 18 subjects with a normal alpha angle (Control). Anterosuperior subchondral femoral neck and acetabular rim BMD were measured using quantitative computed tomography. Activity level was determined using the UCLA activity score. The correlation between BMD and UCLA activity were analysed. The result was a significantly higher BMD for Bump subjects in almost all measured sections. The UCLA score of the Bump versus Control subjects were comparable (8.96 versus 8.77, P = 0.740). While the controls showed no correlation between UCLA and BMD, a positive correlation was found for the Bump subjects on several femoral and acetabular impingement locations. These results support the conclusion that mechanical loading causes subchondral stiffening at the anterosuperior head–neck junction of the femur and anterosuperior acetabular rim. The absence of a correlation between BMD versus UCLA in the Controls supports the hypothesis that activity level may serve as a predictor for higher subchondral BMD in a cam deformity hip joint.

Background Although it is well-established that osteoarthritis (OA) impairs daily-life gait, objective gait assessments are not part of routine clinical evaluation. Wearable inertial sensors provide an easily accessible and fast way to routinely evaluate gait quality in clinical settings. However, during these assessments, more complex and meaningful aspects of daily-life gait, including turning, dual-task performance, and upper body motion, are often overlooked. The aim of this study was therefore to investigate turning, dual-task performance, and upper body motion in individuals with knee or hip OA in addition to more commonly assessed spatiotemporal gait parameters using wearable sensors. Methods Gait was compared between individuals with unilateral knee (n = 25) or hip OA (n = 26) scheduled for joint replacement, and healthy controls (n = 27). For 2 min, participants walked back and forth along a 6-m trajectory making 180° turns, with and without a secondary cognitive task. Gait parameters were collected using 4 inertial measurement units on the feet and trunk. To test if dual-task gait, turning, and upper body motion had added value above spatiotemporal parameters, a factor analysis was conducted. Effect sizes were computed as standardized mean difference between OA groups and healthy controls to identify parameters from these gait domains that were sensitive to knee or hip OA. Results Four independent domains of gait were obtained: speed-spatial, speed-temporal, dual-task cost, and upper body motion. Turning parameters constituted a gait domain together with cadence. From the domains that were obtained, stride length (speed-spatial) and cadence (speed-temporal) had the strongest effect sizes for both knee and hip OA. Upper body motion (lumbar sagittal range of motion), showed a strong effect size when comparing hip OA with healthy controls. Parameters reflecting dual-task cost were not sensitive to knee or hip OA. Conclusions Besides more commonly reported spatiotemporal parameters, only upper body motion provided non-redundant and sensitive parameters representing gait adaptations in individuals with hip OA. Turning parameters were sensitive to knee and hip OA, but were not independent from speed-related gait parameters. Dual-task parameters had limited additional value for evaluating gait in knee and hip OA, although dual-task cost constituted a separate gait domain. Future steps should include testing responsiveness of these gait domains to interventions aiming to improve mobility.

Background Total knee replacement (TKR) is considered an effective intervention of the treatment of advanced knee osteoarthritis (OA) (Kellgren & Lawrence >2). However, a significant proportion of patients could be considered as a poor-responder to TKR (i.e. no or little improvement) in terms of chronic knee pain, functional disability, poor quality of life (QoL), and dissatisfaction after TKR. Both in research and in clinical practice it is challenging to identify those patients with an unfavourable course after TKR. It is difficult though to quantify the proportion of patients with poor response to TKR, as different definitions of, and perspectives (clinician’s and patient’s) on failure are being used. Objectives The aim of this study was to review the literature and summarize definitions of poor response to TKR. Methods A systematic search up to 2016 was performed to identify and review previously used definitions of poor response to primary TKR in the literature. Studies were included if dichotomous definitions of outcome after primary TKR were used, if a prospective design was used and in English full text available. The type, amount and combination of domains (i.e. pain and physical function), outcome measures, type of responses (absolute/relative, change/cut-off), values and moments of follow-up used in definitions were summarized. Results A total of 44 different dichotomous definitions of poor response to TKR, were extracted from 1849 initially identified studies. 34 definitions incorporated one domain, six definitions comprised two domains and four definitions comprised three domains. Eight different domains were used in identified definitions: pain, physical function (mobility), physical functioning (body), QoL, satisfaction, anxiety, depression and patient global assessment. Patient satisfaction was most commonly used (n=10) as single domain with a wide variation in wording of questions and answering categories. The absolute cut-off value was the most common type of response, with large variety in value and timing of follow-up. Table 1 shows one definition for each combination of domains. Conclusion Our review shows that definitions for poor response to TKR are ambiguous. Our findings stress the need for an unambiguous definition of poor response to draw conclusions about the prevalence of poor-responders to TKR across hospitals and countries, and to identify patients at risk. Disclosure of Interests: None declared

Background:Although most of the patients after total knee replacement (TKA) report very satisfied outcome scores, there is still a significant proportion of patients that experience persistent knee pain, functional disability or dissatisfaction after TKA because of osteoarthritis (OA). It is difficult to quantify the proportion of patients with poor response to TKA, as different definitions on failure are being used (1). Additionally, patients and surgeons only agree in 36% on failure of total joint replacement (TJR) (2). This may be caused by different perceptions about concepts underlying poor response to TKA.Objectives:To explore if patients and knee specialists have different views about relevant concepts reflecting poor response to primary TKA.Methods:A qualitative, multicentre study was performed using semi-structured interviews in Belgium and in the Netherlands. Purposive sampling was used to enrich data variation. Twenty-five patients with knee OA without surgical indications (N=2), pre- and postoperative patients (N=11 and N=12, respectively) and fifteen knee specialists (orthopedic surgeons (N=9), physician assistants (N=1), nurse practitioners (N=1) and specialized physiotherapists (N=4)) were interviewed individually. Conversations were audiotaped, transcribed verbatim, and analysed using a thematic analysis.Results:Concepts underlying poor response to TKA were: persistent pain, limited knee function, limitations in physical functioning, complications, unmet expectations, unexpected sequelae and dissatisfaction (Figure 1). The concepts persistent pain, limited knee functioning, complications and limited physical functioning were found to underly expectations and/or unexpected sequelae after TKA. Dissatisfaction was considered a overarching concept resulting from unmet expectations and/or unexpected sequelae after TKA (e.g. long-term use of pain medication, continuous awareness of the prosthesis). All seven concepts were identified by both patients and knee specialists although poor knee function was more often described by patients in terms of prosthesis awareness, whereas knee specialists described poor knee function in terms of instability.Conclusion:Patients and knee specialists identified similar concepts as relevant concepts reflecting poor response to TKA. These results will be used to formulate a uniform definition of poor response to TKA.References:[1]Te Molder MEM, Smolders JMH, Heesterbeek PJC, Van Den Ende CHM. Definitions of poor outcome after total knee arthroplasty: An inventory review. BMC Musculoskelet Disord. 2020;21(1):1–6.[2]Singh J, Mehta B, Mirza S, Figgie M, Sculco P, Parks M, et al. When has a knee or hip replacement failed? A patient perspective. J Rheumatol. 2019;47(9):1–18.Figure 1.Relevant concepts reflecting poor response to TKA according to the patients’ and knee specialists perspectives. Concepts in solid gray were relevant to both, prosthesis awareness was relevant to patients and instability was identified as important outcome by knee specialists.Disclosure of Interests:None declared

Objectives Alarm over the reported high failure rates for metal-on-metal (MoM) hip implants as well as their potential for locally aggressive Adverse Reactions to Metal Debris (ARMDs) has prompted government agencies, internationally, to recommend the monitoring of patients with MoM hip implants. Some have advised that a blood ion level >7 µg/L indicates potential for ARMDs. We report a systematic review and meta-analysis of the performance of metal ion testing for ARMDs. Methods We searched MEDLINE and EMBASE to identify articles from which it was possible to reconstruct a 2 × 2 table. Two readers independently reviewed all articles and extracted data using explicit criteria. We computed a summary receiver operating curve using a Bayesian random-effects hierarchical model. Results Our literature search returned 575 unique articles; only six met inclusion criteria defined a priori. The discriminative capacity of ion tests was homogeneous across studies but that there was substantial cut-point heterogeneity. Our best estimate of the “true” area under curve (AUC) for metal ion testing is 0.615, with a 95% credible interval of 0.480 to 0.735, thus we can state that the probability that metal ion testing is actually clinically useful with an AUC ≥ 0.75 is 1.7%. Conclusion Metal ion levels are not useful as a screening test for identifying high risk patients because ion testing will either lead to a large burden of false positive patients, or otherwise marginally modify the pre-test probability. With the availability of more accurate non-invasive tests, we did not find any evidence for using blood ion levels to diagnose symptomatic patients. Cite this article: M. Pahuta, J. M. Smolders, J. L. van Susante, J. Peck, P. R. Kim, P. E. Beaule. Blood metal ion levels are not a useful test for adverse reactions to metal debris: a systematic review and meta-analysis. Bone Joint Res 2016;5:379–386. DOI: 10.1302/2046-3758.59.BJR-2016-0027.R1.

Background Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release. Patients and methods 71 patients (< 65 years old) were randomly assigned to receive either a resurfacing (R) hip arthroplasty (n = 38) or a conventional metal-on-metal (C) hip arthroplasty (n = 33). Functional outcomes were assessed preoperatively and at 6, 12, and 24 months. Cobalt and chromium blood levels were analyzed preoperatively and at 3, 6, 12, and 24 months. Results All functional outcome scores improved for both groups. At 12 and 24 months, the median UCLA activity score was 8 in the R patients and 7 in the C patients (p < 0.05). At 24 months, OHS was median 16 in C patients and 13 in R patients (p < 0.05). However, in spite of randomization, UCLA scores also appeared to be higher in R patients at baseline. Satisfaction was similar in both g...

We undertook a randomised prospective follow-up study of changes in peri-prosthetic bone mineral density (BMD) after hip resurfacing and compared them with the results after total hip replacement. A total of 59 patients were allocated to receive a hip resurfacing (n = 29) or an uncemented distally fixed total hip replacement (n = 30). The BMD was prospectively determined in four separate regions of interest of the femoral neck and in the calcar region corresponding to Gruen zone 7 for the hip resurfacing group and compared only to the calcar region in the total hip replacement group. Standardised measurements were performed pre-operatively and after three, six and 12 months. The groups were well matched in terms of gender distribution and mean age. The mean BMD in the calcar region increased after one year to 105.2% of baseline levels in the resurfaced group compared with a significant decrease to 82.1% in the total hip replacement group (p < 0.001) by 12 months. For the resurfaced group, there was a decrease in bone density in all four regions of the femoral neck at three months which did not reach statistical significance and was followed by recovery to baseline levels after 12 months. Hip resurfacing did indeed preserve BMD in the inferior femoral neck. In contrast, a decrease in the mean BMD in Gruen zone 7 followed uncemented distally fixed total hip replacement. Long term follow-up studies are necessary to see whether this benefit in preservation of BMD will be clinically relevant at future revision surgery.

We studied whether bone mineral density (BMD) is preserved without significant femoral neck narrowing (FNN) after hip resurfacing (RHA) (n=42) versus small diameter metal-on-metal total hip arthroplasty (MoM THA) (n=40). In this three to five year randomized trial BMD was measured in the calcar with dual energy absorptiometry (DXA) preoperatively, at three and six months, one, two, three and five years postoperatively. Four additional BMD regions of interest (ROIs) and femoral neck narrowing (FNN) were measured after RHA. BMD in the calcar increased to 107% (P

Item does not contain fulltext Forty-eight unilateral hip resurfacing arthroplasty patients were evaluated for cobalt and chromium levels. The metal ion trend of 42 well-functioning patients was compared with six sub-optimal functioning patients. Median metal ion levels were significantly higher for the sub-optimal group. For the well-functioning implants, the percentage of patients with increasing cobalt/chromium levels between two consecutive time-intervals ('risers') gradually decreased from 90/86% (0-3 months) to 22/22% (24-36 months). The percentage of patients with increasing metal ion levels was higher in the sub-optimal group. The median absolute increase of this 'risers' subgroup was significantly lower for the well-functioning group at 12-24 months. Sub-optimal functioning MoM implants have a different metal ion trend than well-functioning implants, a higher chance of 'risers' and a larger absolute increase in time.

Background Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release. Patients and methods 71 patients (< 65 years old) were randomly assigned to receive either a resurfacing (R) hip arthroplasty (n = 38) or a conventional metal-on-metal (C) hip arthroplasty (n = 33). Functional outcomes were assessed preoperatively and at 6, 12, and 24 months. Cobalt and chromium blood levels were analyzed preoperatively and at 3, 6, 12, and 24 months. Results All functional outcome scores improved for both groups. At 12 and 24 months, the median UCLA activity score was 8 in the R patients and 7 in the C patients (p < 0.05). At 24 months, OHS was median 16 in C patients and 13 in R patients (p < 0.05). However, in spite of randomization, UCLA scores also appeared to be higher in R patients at baseline. Satisfaction was similar in both groups at 24 months. Cobalt concentrations were statistically significantly higher for R patients only at 3 and 6 months. Chromium levels remained significantly higher for R patients until 24 months. No pseudotumors were encountered in either group. One R patient was revised for early aseptic loosening and in 2 C patients a cup insert was exchanged for recurrent dislocation. Interpretation R patients scored higher on UCLA, OHS, and satisfaction at some time points; however, as for the UCLA, preoperative levels were already in favor of R. The differences, although statistically significant, were of minor clinical importance. Chromium blood levels were statistically significantly higher for R patients at all follow-up measurements, whereas for cobalt this was only observed up to 6 months. The true value of resurfacing hip arthroplasty over conventional metal-on-metal hip arthroplasty will be determined by longer follow-up and a possible shift of balance between their respective (dis)advantages.

Background and purpose Hip resurfacing arthroplasty (RHA) is done in patients who often have a high preference for the method. This preference can influence the clinical outcome and satisfaction. We evaluated the potential influence of this preference bias. Patients and methods From an ongoing randomized trial comparing RHA with total hip arthroplasty, 28 consecutive patients (28 hips) who had been allocated to an RHA were characterized as the “randomized” group. 22 other patients (24 hips) who had refused participation and had especially requested an RHA were characterized as the “preference” group. Harris hip score (HHS), Oxford hip score (OHS), University of California at Los Angeles activity scale (UCLA), Short Form 12 (SF-12), and visual analog scale satisfaction score (VAS) were assessed in both groups. Results Both groups had a high implant satisfaction score (97/100 for the “preference” group and 93/100 for the “randomized” group) at 12 months. The HHS, OHS, and UCLA were similar at baseline and also revealed a similar improvement up to 12 months (p < 0.001). Regarding the SF-12, the “preference” group scored lower on the mental subscale preoperatively (p = 0.03), and there was a greater increase after 12 months (p = 0.03). Interpretation We could not show that there was any influence of preference on satisfaction with the implant and early clinical outcome in patients who underwent RHA. The difference in mental subscale scores between groups may still indicate a difference in psychological profile.

Contains fulltext : 96098.pdf (Publisher’s version ) (Closed access) Metal ions generated from joint replacements are a cause for concern. There is no consensus on the best surrogate measure of metal ion exposure, and both serum and whole blood measurements are used in clinical practice. This study provides a guideline for interpretation of metal ion analysis in clinical practice. In a prospective trial comparing hip resurfacing (HR) with a conventional metal-on-metal (MoM) total hip arthroplasty (THA) cobalt and chromium levels were determined for whole blood and serum in 343 paired samples at regular intervals up to 24 months postoperatively. Cobalt whole blood and serum levels increased significantly after both procedures. Cobalt concentrations were significantly higher for the HR group compared to the THA group, at 3, 6 and 12 months, for whole blood and serum. At 24 months cobalt levels decreased and differences between HR and THA were no longer significant. In contrast, chromium whole blood levels remained significantly higher for HR until 24 months. Whole blood and serum levels could not be used interchangeably. The mean differences for cobalt and chromium between blood and serum values were +0.13 microg/L and -0.91 microg/L respectively. Regression analysis provided a formula for conversion from serum to blood of 0.34+[0.88*Co serum] for cobalt and 0.14 + [0.58*Cr serum] for chromium, with an acceptable prediction error below +/-1.0 microg/L. Cobalt and chromium levels were significantly higher for HR versus THA, especially during the run-in phase of one year. Overall, the metal ion levels were well below 5 microg/L. We cannot recommend the use of whole blood over serum measurements or vice versa. The provided conversion formula between whole blood and serum in combination with the presented practical guidelines may be useful for clinical practice.

To evaluate the short-term outcome of osteochondritis dissecans (OCD) treated with mosaic osteochondral autograft transplantation (OAT), 7 male patients (mean age 33.4) with 8 OCD lesions on the lateral border of the medial femoral condyle were prospectively followed. Patients were evaluated by the International Knee Documention Committee (IKDC) score and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaires preoperatively, at 6 months and 1 year after surgery. MRI evaluation using the modified Sanders score was performed at 1-year follow-up. The IKDC subjective score and all subscales of the KOOS improved significantly. MRI evaluation showed good surface congruency, no oedema or protuberance of the osteocartilaginous cylinders, good similarity of cartilage thickness and a non-complete osseous integration. With the small numbers of patients available, no correlation could be found between MRI findings, percentage of defect coverage and patient satisfaction. Mosaic OAT appeared in this study as a valid treatment option in selected cartilage defects. OCD lesions improved significantly following osteochondral transplantation. The limitations of this technique are the number and size of the plugs needed to repair the defect. Future research should focus on identifying the appropriate choice of operative treatment for well defined subtypes of articular cartilage lesions, rather than searching for one superior technique for all.

Contains fulltext : 79990.pdf (Publisher’s version ) (Closed access) BACKGROUND: Operation of hip resurfacing prosthesis is a technically demanding procedure accompanied by a learning curve. To our knowledge no objective data on this learning curve are available in the literature. METHODS: For the first 40 resurfacing hip prostheses implanted by a single-surgeon radiographic 'learning curve' analysis was performed. Optimal implant positioning on preoperative digital templating was compared with the eventual implant position postoperatively, measured by six establishes radiographic parameters and compared for four chronological cohorts of patients. RESULTS: A learning curve was clearly present and an optimal result was established in the last cohort. Pitfalls were a relatively steep cup position initially and a stem position in the posterior 1/3 of the collum. Besides marginal medialization a fully anatomic reconstruction of the center of rotation was achieved. CONCLUSION: In total hip resurfacing one should recognize the presence of a learning curve. This learning curve appears to be acceptable and a reproducible optimal implant positioning can be achieved quickly.

Contains fulltext : 70643.pdf (Publisher’s version ) (Open Access) Osteochondral transplantation is a successful treatment for full-thickness cartilage defects, which without treatment would lead to early osteoarthritis. Restoration of surface congruency and stability of the reconstruction may be jeopardized by early mobilization. To investigate the biomechanical effectiveness of osteochondral transplantation, we performed a standardized osteochondral transplantation in eight intact human cadaver knees, using three cylindrical plugs on a full-thickness cartilage defect, bottomed on one condyle, unbottomed on the contralateral condyle. Surface pressure measurements with Tekscan pressure transducers were performed after five conditions. In the presence of a defect the border contact pressure of the articular cartilage defect significantly increased to 192% as compared to the initially intact joint surface. This was partially restored with osteochondral transplantation (mosaicplasty), as the rim stress subsequently decreased to 135% of the preoperative value. Following weight bearing motion two out of eight unbottomed mosaicplasties showed subsidence of the plugs according to Tekscan measurements. This study demonstrates that a three-plug mosaicplasty is effective in restoring the increased border contact pressure of a cartilage defect, which may postpone the development of early osteoarthritis. Unbottomed mosaicplasties may be more susceptible for subsidence below flush level after (unintended) weight bearing motion.

In an attempt to reduce health care expenses, regulated competition between health care providers has been introduced in The Netherlands. As for total hip and knee arthroplasties, health care providers have to publish their prices to make them available for the insurance companies and the public. Eventually, competition between health care providers should result in optimal care for lower prices. The purpose of this study was to define the patients' consciousness of the overall costs and specialist's fee for a total knee arthroplasty. Thirty-nine patients with a recent total knee arthroplasty were asked to estimate the total costs and the surgeon's fee of this procedure. The average overall cost of a total knee arthroplasty in our hospital was Euro 11.500. The orthopaedic surgeon's fee represents a non-negotiable 5% of these total costs. The mean estimate of the overall costs of a total knee arthroplasty by the patients was Euro 10.000 (range: Euro 600 to Euro 55.000). Only 26% of the patients (n = 10) gave an estimate within the accepted "correct" range of Euro 8.500 to Euro 14.500. The surgeon's fee was estimated at 32% (range: 5% to 75%) of the total costs and a majority reckoned the actual fraction of 5% was low. Patients have a poor notion of the overall costs of a total knee arthroplasty and strongly overestimate the specialist's fee. Whether the introduction of budget competition in health care may actually result in a decrease in health care costs remains to be seen.