Rob G. H. H. Nelissen

Total Ankle Arthroplasty in Inflammatory Joint Disease with Use of Two Mobile-Bearing Designs

BACKGROUND Interest in mobile-bearing total ankle arthroplasty has increased in recent years. However, to our knowledge, no study has focused exclusively on patients with the diagnosis of inflammatory joint disease or has provided a detailed analysis of the risk factors for failure. METHODS A prospective observational study of the results of cementless mobile-bearing total ankle arthroplasty in patients with inflammatory joint disease (mainly rheumatoid arthritis) was conducted at two centers. Ninety-three total ankle arthroplasties were performed. The LCS (low contact stress) prosthesis was used initially, in nineteen ankles, between 1988 and 1992, and a modification of the LCS prosthesis, the Buechel-Pappas design, was used in seventy-four ankles between 1993 and 1999. Clinical and radiographic follow-up was performed at yearly intervals. Three clinical scoring systems were used, and any complication was recorded throughout follow-up. Actuarial survival (with revision as the end point), multivariate analysis, and a competing risk approach were used to describe the long-term outcome. RESULTS The clinical result at one year after surgery showed a significant improvement in the scores on all three scoring systems (p < 0.05). Ankle dorsiflexion (mean, 7 degrees ) also improved significantly (p < 0.05) compared with the preoperative state. The most frequent complication was a malleolar fracture, which occurred in twenty ankles. Only when it occurred in combination with a deformity in the frontal plane did this complication have an adverse effect on the end result. At a mean follow-up of eight years, seventeen patients (twenty-one ankles) had died and fifteen ankles had been revised because of aseptic loosening (six ankles), primary or secondary axial deformity with edge-loading (six ankles), deep infection (two ankles), and a severe wound-healing problem (one ankle), leaving fifty-seven ankles (61%) that were evaluated. The mean overall survival rate at eight years was 84%. An increased failure rate was encountered in ankles with a preoperative deformity in the frontal plane of >10 degrees (p = 0.03) and in ankles in which an undersized tibial component had been implanted (p = 0.02). CONCLUSIONS Mobile-bearing total ankle arthroplasty is a valid treatment option for the rheumatoid ankle if proper indications are used. Aseptic loosening and persistent deformity are the most important modes of failure.

Association between weight or body mass index and hand osteoarthritis: a systematic review

Objective To investigate the association between weight or body mass index (BMI) and the development of hand osteoarthritis. Methods Systematic review of observational studies. Medical databases were searched up to April 2008. Articles that presented data on the association between weight and hand osteoarthritis were selected. The qualities of these studies were then assessed by two independent reviewers using a 19 criteria scoring system. Using the mean scores of all studies as a cut-off value, the studies were deemed as high or low quality. Study quality and study designs were combined to determine the level of evidence using best-evidence synthesis, which consisted of five levels of evidence. Results From the 25 studies included, two had cohort, three case–control and 20 cross-sectional study designs. Fifteen studies were considered high-quality studies. Of these high-quality studies, one cohort, two case–control and seven cross-sectional studies showed a positive association between weight or BMI and hand osteoarthritis. Based on three high-quality studies with preferred study designs (one cohort and two case–control) with a positive association, the level of evidence of the association between overweight and developing hand osteoarthritis is moderate. The approximate risk ratio of this association is 1.9. Conclusion Weight or BMI is associated with the development of hand osteoarthritis. The level of evidence of published studies is moderate according to best-evidence synthesis. Further high-quality cohort or case–control studies are needed to elucidate the role of weight in hand osteoarthritis.

The infrapatellar fat pad of patients with osteoarthritis has an inflammatory phenotype

Objectives Obesity is a risk factor for the development of osteoarthritis (OA) in hands and knees. Adipose tissue can secrete different adipokines with powerful immunomodulatory effects. The infrapatellar fat pad (IFP) is an intra-articular organ in the vicinity of the synovium and cartilage. It is hypothesised that IFP-derived soluble factors could contribute to pathological processes in the knee joint. A study was therefore undertaken to compare the release of inflammatory mediators in the IFP and subcutaneous adipose tissue (ScAT) and to characterise the adipocytes and immune cell infiltrate in these tissues. Methods Paired IFP and ScAT samples were obtained from 27 patients with primary OA. The stromal vascular cell fraction (SVF) was isolated and characterised by fluorescence activated cell sorting. Cytokine and adipokine release in fat- and adipocyte-conditioned media was measured by luminex. Results IFP secreted higher levels of inflammatory mediators such as interleukin 6 (IL-6), adipsin, adiponectin and visfatin than ScAT. This could be due to differences in the phenotype of adipocytes and/or in the composition and phenotype of the SVF cells. IFP adipocyte-conditioned media showed a trend towards more IL-6 and adipsin than ScAT. Moreover, the SVF fraction of IFP contained more cells/g tissue, a lower percentage of T cells and a higher percentage of mast cells than ScAT. In addition, T cells had a predominantly pro-inflammatory phenotype while macrophages had a mixed pro- and anti-inflammatory phenotype in the IFP. Conclusion There are profound differences in secreted inflammatory factors and immune cell composition between the IFP and ScAT. These data indicate that IFP-derived soluble mediators could contribute to pathophysiological processes in the OA knee joint.

Neurological recovery in obstetric brachial plexus injuries: an historical cohort study

An historical cohort study was conducted to investigate the rate and extent of neurological recovery in obstetric brachial plexus injury (OBPI) and to identify possible prognostic factors in a cohort of children with OBPI from birth to 7 years. All children (n=56; 31 females, 25 males) with OBPI were evaluated at fixed time intervals by one examiner. They underwent a final neurological examination at a mean age of 3 years 10 months (range 1 to 7 years). Neurological outcome was not as favourable as is often reported: complete neurological recovery occurred in 37 out of 56 children (66%). In half of these there was delayed recovery, in which case complete neurological recovery was assessed from 1.5 to 16 months of age (median age 6.5 months, SD 4.2 months). External rotation and supination were the last to recover and recovered the least. Although biceps function at three months was considered to be the best indicator for operative treatment, external rotation and supination were found to be better in predicting eventual complete recovery. Initial symptoms directly post partum were not found to be prognostic. Functional outcome was mainly reported to be good.

Gait analysis after successful mobile bearing total ankle replacement.

Background: The effect of total ankle replacement on gait is not fully known in terms of joint kinematics, ground reaction force, and activity of the muscles of the lower leg. Methods: A comparative gait study was done in 10 patients after uneventful unilateral mobile-bearing total ankle replacement and 10 healthy controls. A rigid body model was used to describe the motion of the knee and the three-dimensional motion of the ankle-hindfoot complex during barefoot walking. An opto-electronic motion analysis system was used to analyze bilateral movement patterns, synchronized with recordings of the ipsilateral vertical ground reaction forces and the electromyographic activity of four lower leg muscles. Results: Velocity was 6% lower in the patient group. Dorsiflexion in the operated ankles was reduced (p < 0.001). No differences were found in the joint angular pattern of the knee joint and only minimal changes were found at the hindfoot-to-tibia and forefoot-to-hindfoot levels. The ground reaction force at midstance was somewhat increased (p = 0.005), while the magnitude of the vertical peak at terminal stance was decreased (p < 0.001). EMG activity patterns in the patient group were normal except for a higher activity of the gastrocnemius in early stance and the anterior tibial muscle in late stance. Conclusions: There is a near normal gait pattern in terms of joint kinematics of the knee, ankle, and foot after uneventful mobile-bearing total ankle replacement. The ground reaction forces and the EMG activity, however, do not fully normalize.

The effect of hydroxyapatite on the micromotion of total knee prostheses : A prospective, randomized, double-blind study

A prospective, randomized, double-blind study was performed to evaluate three different means of fixing tibial components during total knee arthroplasty. Eleven components fixed with cement, ten hydroxyapatite-coated components fixed without cement, and ten noncoated components fixed without cement were studied. A posterior cruciate ligament-retaining total condylar implant was used. Micromotion of the components was assessed with roentgen stereophotogrammetric analysis during the two-year follow-up period. There were no significant differences among the patients with regard to age (mean [and standard deviation], 68 ± 11.6 years), body-mass index (mean, 23 ± 2.8 kilograms per square meter), or stage of osteoarthrosis (mean, 4 ± 2.4 according to the classification system of Ahlbäck and 5 ± 0.6 according to that of Larsen et al.). The diagnosis was osteoarthrosis in five knees, and it was rheumatoid arthritis in twenty-six. The clinical scores were similar among the study groups. According to the system of the Knee Society, the mean preoperative functional score was 10 ± 2.9 points and the mean preoperative knee score was 24 ± 3.2 points. At the two-year follow-up evaluation, these scores were 41 ± 8.3 and 79 ± 3.2 points, respectively. A significant difference with regard to micromotion was found between the noncoated components fixed without cement and the hydroxyapatite-coated components fixed without cement as well as between the noncoated components fixed without cement and the components fixed with cement (p < 0.001, analysis of variance). The hydroxyapatite-coated components fixed without cement and the components fixed with cement both had far less micromotion along the longitudinal axis (subsidence) throughout the follow-up period than did the noncoated components fixed without cement. At the two-year follow-up evaluation, the subsidence of the noncoated components was -0.73 ± 0.924 millimeter, the subsidence of the cemented components was -0.05 ± 0.109 millimeter, and the subsidence of the hydroxyapatite-coated components was -0.06 ± 0.169 millimeter. The cemented components as well as the hydroxyapatite-coated components also had less translation along the transverse axis (p < 0.001, analysis of variance) and the sagittal axis (p < 0.001, analysis of variance) compared with the noncoated components. In conclusion, micromotion of hydroxyapatite-coated tibial components fixed without cement was similar to that of tibial components fixed with cement. Therefore, hydroxyapatite, a biological mediator, may be necessary for the adequate fixation of tibial components when cement is not used.

CHECK (Cohort Hip and Cohort Knee): similarities and differences with the Osteoarthritis Initiative

Objective: To describe the osteoarthritis study population of CHECK (Cohort Hip and Cohort Knee) in comparison with relevant selections of the study population of the Osteoarthritis Initiative (OAI) based on clinical status and radiographic parameters. Methods: In The Netherlands a prospective 10-year follow-up study was initiated by the Dutch Arthritis Association on participants with early osteoarthritis-related complaints of hip and/or knee: CHECK. In parallel in the USA an observational 4-year follow-up study, the OAI, was started by the National Institutes of Health, on patients with or at risk of symptomatic knee osteoarthritis. For comparison with CHECK, the entire cohort and a subgroup of individuals excluding those with exclusively hip pain were compared with relevant subpopulations of the OAI. Results: At baseline, CHECK included 1002 participants with in general similar characteristics as described for the OAI. However, significantly fewer individuals in CHECK had radiographic knee osteoarthritis at baseline when compared with the OAI (p<0.001). In contrast, at baseline, the CHECK cohort reported higher scores on pain, stiffness and functional disability (Western Ontario and McMaster osteoarthritis index) when compared with the OAI (all p<0.001). These differences were supported by physical health status in contrast to mental health (Short Form 36/12) was at baseline significantly worse for the CHECK participants (p<0.001). Conclusion: Although both cohorts focus on the early phase of osteoarthritis, they differ significantly with respect to structural (radiographic) and clinical (health status) characteristics, CHECK expectedly representing participants in an even earlier phase of disease.

Shoulder contracture and osseous deformity in obstetrical brachial plexus injuries

Background: The purposes of this study were to determine the prevalence of and the association between shoulder contracture and osseous deformity in a cohort of children with an obstetrical brachial plexus injury and to identify the risk factors for these complications.Methods: In a retrospective cohort study, all children with an obstetrical brachial plexus injury who had been born between January 1991 and January 1998 at one academic medical center and all those with the same diagnosis who had been born elsewhere during the same period and were referred to the medical center within six weeks after delivery were evaluated at fixed time-intervals by one examiner. The patients underwent a final orthopaedic, neurological, and radiographic examination at a mean age of 3.7 years (range, one to seven years). Shoulder contracture was defined as a decrease in the passive range of motion in one or more directions compared with the range on the unaffected side. Osseous deformity was defined as a nonspherical humeral head or an abnormal glenoid.Results: The prevalence of a shoulder contracture of >10° was 56% (twenty-nine of fifty-two patients), and the prevalence of an osseous deformity was 33% (sixteen of forty-eight patients with complete radiographic follow-up). In the children in whom complete neurological recovery was delayed (i.e., recovery was more than three weeks after birth), the prevalence of shoulder contracture was 54% (thirteen of twenty-four patients) and the prevalence of osseous deformity was 26% (six of twenty-three patients). A strong association was noted between shoulder contracture and osseous deformity (p = 0.004). Directly after birth, the presence of a clavicular fracture was the only factor that was associated (p = 0.016) with the development of an osseous deformity (but not with a shoulder contracture). At a later stage, speed and extent of neurological recovery were related to shoulder contracture and osseous deformity. An asymmetric appearance was noticed in children who had a contracture, including those who had complete neurological recovery.Conclusions: The prevalence of shoulder contracture and osseous deformity in children with obstetrical brachial plexus injury was high, even in those with complete neurological recovery. These complications were strongly associated with one another. No symptom that appeared immediately after birth was identified as a factor that would predict the development of future shoulder contracture. A clavicular fracture was found to be significantly associated with the development of an osseous deformity at a later stage.Level of Evidence: Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Digital automated RSA compared to manually operated RSA

The accuracy of digital Roentgen stereophotogrammetric analysis (RSA) was compared to the accuracy of a manually operated RSA system. For this purpose, we used radiographs of a phantom and radiographs of patients. The radiographs of the patients consisted of double examinations of 12 patients that had a tibial osteotomy and of double examinations of 12 patients that received a total hip prosthesis. First, the radiographs were measured manually with an accurate measurement table. Subsequently, the images were digitized by a film scanner at 150 DPI and 300 DPI resolutions and analyzed with the RSA-CMS software. In the phantom experiment, the manually operated system produced significantly better results than the digital system, although the maximum difference between the median values of the manually operated system and the digital system was as low as 0.013mm for translations and 0.033 degrees for rotations. In the radiographs of the patients, the manually operated system and the digital system produced equally accurate results: no significant differences in translations and rotations were found. We conclude that digital RSA is an accurate, fast, and user friendly alternative for manually operated RSA. Currently, digital RSA systems are being used in a growing number of clinical RSA-studies.

Early migration of tibial components is associated with late revision: a systematic review and meta-analysis of 21,000 knee arthroplasties.

Purpose We performed two parallel systematic reviews and meta-analyses to determine the association between early migration of tibial components and late aseptic revision. Methods One review comprised early migration data from radiostereometric analysis (RSA) studies, while the other focused on revision rates for aseptic loosening from long-term survival studies. Thresholds for acceptable and unacceptable migration were determined according to that of several national joint registries: < 5% revision at 10 years. Results Following an elaborate literature search, 50 studies (involving 847 total knee prostheses (TKPs)) were included in the RSA review and 56 studies (20,599 TKPs) were included in the survival review. The results showed that for every mm increase in migration there was an 8% increase in revision rate, which remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. Consequently, migration up to 0.5 mm was considered acceptable during the first postoperative year, while migration of 1.6 mm or more was unacceptable. TKPs with migration of between 0.5 and 1.6 mm were considered to be at risk of having revision rates higher than 5% at 10 years. Interpretation There was a clinically relevant association between early migration of TKPs and late revision for loosening. The proposed migration thresholds can be implemented in a phased, evidence-based introduction of new types of knee prostheses, since they allow early detection of high-risk TKPs while exposing only a small number of patients.