Nerve injuries do occur in elbow arthroscopy.

PURPOSE: The purpose is to create more awareness as well as emphasize the risk of permanent nerve injury as a complication of elbow arthroscopy. METHODS: Patients who underwent elbow arthroscopy complicated by permanent nerve injury were retrospectively collected. Patients were collected using two strategies: (1) by word-of-mouth throughout the Dutch Society of Shoulder and Elbow Surgery, and the Leiden University Nerve Centre, and (2) approaching two medical liability insurance companies. Medical records were reviewed to determine patient characteristics, disease history and postoperative course. Surgical records were reviewed to determine surgical details. RESULTS: A total of eight patients were collected, four men and four women, ageing 21-54 years. In five out of eight patients (62.5%), the ulnar nerve was affected; in the remaining three patients (37.5%), the radial nerve was involved. Possible causes for nerve injury varied among patients, such as portal placement and the use of motorized instruments. CONCLUSIONS: A case series on permanent nerve injury as a complication of elbow arthroscopy is presented. Reporting on this sequel in the literature is little, however, its risk is not to be underestimated. This study emphasizes that permanent nerve injury is a complication of elbow arthroscopy, concurrently increasing awareness and thereby possibly aiding to prevention. LEVEL OF EVIDENCE: IV, case series.

Migration and clinical outcome of mobile-bearing versus fixed-bearing single-radius total knee arthroplasty.

Background and purpose - Mobile-bearing total knee prostheses (TKPs) were developed in the 1970s in an attempt to increase function and improve implant longevity. However, modern fixed-bearing designs like the single-radius TKP may provide similar advantages. We compared tibial component migration measured with radiostereometric analysis (RSA) and clinical outcome of otherwise similarly designed cemented fixed-bearing and mobile-bearing single-radius TKPs. Patients and methods - RSA measurements and clinical scores were assessed in 46 randomized patients at baseline, 6 months, 1 year, and annually thereafter up to 6 years postoperatively. A linear mixed-effects model was used to analyze the repeated measurements. Results - Both groups showed comparable migration (p = 0.3), with a mean migration at 6-year follow-up of 0.90 mm (95% CI 0.49-1.41) for the fixed-bearing group compared with 1.22 mm (95% CI 0.75-1.80) for the mobile-bearing group. Clinical outcomes were similar between groups. 1 fixed-bearing knee was revised for aseptic loosening after 6 years and 2 knees (1 in each group) were revised for late infection. 2 knees (1 in each group) were suspected for loosening due to excessive migration. Another mobile-bearing knee was revised after an insert dislocation due to failure of the locking mechanism 6 weeks postoperatively, after which study inclusion was preliminary terminated. Interpretation - Fixed-bearing and mobile-bearing single-radius TKPs showed similar migration. The latter may, however, expose patients to more complex surgical techniques and risks such as insert dislocations inherent to this rotating-platform design.

The foot function index is more sensitive to change than the Leeds Foot Impact Scale for evaluating rheumatoid arthritis patients after forefoot or hindfoot reconstruction.

PURPOSE: This study examines the responsiveness of the Foot Functional Index (FFI) and Leeds Foot Impact Scale for Rheumatoid Arthritis (LFIS-RA) in rheumatoid arthritis (RA) patients receiving a forefoot or hindfoot reconstruction. METHODS: This was a prospective cohort study including 30 rheumatoid arthritis patients with severe rheumatoid foot deformities in need for surgical correction. Responsiveness was measured using distribution-based methods (standardized effect size, standardized response mean and Guyatt responsiveness ratio) and anchor-based methods (receiver operating characteristics curves and correlation analyses) by making use of an anchor question. To examine the depth of the questionnaires we measured the floor and ceiling effects. RESULTS: The study population consisted of three males and 27 females, with a mean age of 62 years. The mean follow-up time was 38 months. Twenty-two feet received a forefoot reconstruction and eight feet a triple arthrodesis. For the FFI the SES was -0.80, SRM was -0.85 and the GRR was -1.25. For the LFIS-RA the SES was 0.58, SRM was 0.58 and the GRR was 0.88. The AUC was 0.741 and 0.645 for FFI and LFIS, respectively. Contrary to the LFIS-RA, the FFI showed a significant correlation between change score and the anchor question. Both questionnaires did not show a significant floor or ceiling effect. CONCLUSION: The FFI showed a large responsiveness and the LFIS- RA showed moderate responsiveness in rheumatoid arthritis patients receiving forefoot or hindfoot surgery, without floor or ceiling effects in both questionnaires.

Feasibility and barriers of treating clubfeet in four countries.

PURPOSE: The purpose of this study was to elucidate why neglected clubfeet still exists despite the availability of a highly (cost)-effective treatment-the Ponseti treatment. METHODS: A qualitative and partly quantitative study with semi-structured interviews was conducted in four countries: the Netherlands, South Africa, Argentina and Indonesia with both caregivers, mostly parents, of children with clubfoot and practitioners treating clubfoot. The topics discussed with the caregivers (n = 51) were the conceptions of the cause of clubfeet, received information, accessibility, financial aspects, and social stigma. With the practitioners (n = 11) the focus of the interviews was the treatment protocol and finance. RESULTS: Several barriers towards the start of the treatment were highlighted. At all places treatment was financed by the government, insurance or charity. Nevertheless, the cost of transport and missed working days formed a barrier, although there is a large difference between and within countries. Poverty, long travel duration, and beliefs of supernatural causes for the clubfoot result in delay in the start of treatment. CONCLUSION: These are problems we need to address when making effective treatment available for every child to diminish the burden of neglected clubfoot; especially accessible clinics in rural areas can be a good alternative to highly specialized hospitals in large cities. We as a community should try to find and overcome the barriers to treat these patients, because we have a relatively easy and highly cost-effective treatment option which can be given by trained non-physicians supervised by an interested medical doctor.

Hemiarthroplasties in young patients with osteonecrosis or a tumour of the proximal femur; an observational cohort study.

BACKGROUND: The failure scenario in total hip arthroplasty (THA), in younger patients, is dependent on the fixation and wear of the acetabular component. In selected cases, where endoprosthetic replacement of the femoral head is unavoidable for limb salvage or functional recovery, hemiarthroplasty can be chosen as an alternative. The purpose of this study is to evaluate hemiarthroplasty as treatment strategy for young patients with osteonecrosis or a tumour of the proximal femur. METHODS: Between 1985 and 2008, 42 hemiarthroplasties (unipolar and bipolar) were performed in patients younger than 65 years with osteonecrosis (n=13) or a tumour of the proximal femur (n=29). All patients were seen at yearly follow-up examination and evaluated. Revision or conversion to a THA was regarded as a failure of the implant. A Kaplan Meier analysis was performed. To determine significant differences between categorical groups, the Pearson chi-square test was used. In numerical groups the independent T-test and One-way ANOVA were used. RESULTS: After a mean follow-up of 7.1 years, failure of the hemiarthroplasty occurred 6 times. The Kaplan Meier survival analysis with conversion to THA or revision as endpoint of the bipolar hemiarthroplasties (n=38) shows a 96% survival at 15, and 60% at 20 years. In the unipolar type (n=4) we found a conversion rate of 50% within 3 years. CONCLUSIONS: Bipolar hemiarthroplasty is a reasonable alternative in a young patient with osteonecrosis or a tumour of the proximal femur as indication. Because of the high conversion rate after unipolar hemiarthroplasties, we would not recommend this type of prosthesis in the young patient.

The mid-term outcome of total ankle arthroplasty and ankle fusion in rheumatoid arthritis: a systematic review.

BACKGROUND: While arthrodesis is the standard treatment of a severely arthritic ankle joint, total ankle arthroplasty has become a popular alternative. This review provides clinical outcomes and complications of both interventions in patients with rheumatoid arthritis. METHODS: Studies were obtained from Pubmed, Embase and Web of Science (January 1980-June 2011) and additional manual search. INCLUSION CRITERIA: original clinical study, > 5 rheumatoid arthritis (population), internal fixation arthrodesis or three-component mobile bearing prosthesis (intervention), ankle scoring system (outcome). The clinical outcome score, complication- and failure rates were extracted and the methodological quality of the studies was analysed. RESULTS: 17 observational studies of 868 citations were included. The effect size concerning total ankle arthroplasty ranged between 1.9 and 6.0, for arthrodesis the effect sizes were 4.0 and 4.7. Reoperation due to implant failure or reoperation due to non-union, was 11% and 12% for respectively total ankle arthroplasty and arthrodesis. The methodological quality of the studies was low (mean 6.4 out of a maximum of 14 points) and was lower for arthrodesis (mean 4.8) as compared to arthroplasty (mean 7.8) (p = 0.04). CONCLUSIONS: 17 observational and no (randomized) controlled clinical trials are published on the effectiveness of arthroplasty or arthrodesis of the ankle in rheumatoid arthritis. Regardless of the methodological limitations it can be concluded that both interventions show clinical improvement and in line with current literature neither procedure is superior to the other.

Measuring femoral lesions despite CT metal artefacts: a cadaveric study.

OBJECTIVE: Computed tomography is the modality of choice for measuring osteolysis but suffers from metal-induced artefacts obscuring periprosthetic tissues. Previous papers on metal artefact reduction (MAR) show qualitative improvements, but their algorithms have not found acceptance for clinical applications. We investigated to what extent metal artefacts interfere with the segmentation of lesions adjacent to a metal femoral implant and whether metal artefact reduction improves the manual segmentation of such lesions. MATERIALS AND METHODS: We manually created 27 periprosthetic lesions in 10 human cadaver femora. We filled the lesions with a fibrotic interface tissue substitute. Each femur was fitted with a polished tapered cobalt-chrome prosthesis and imaged twice--once with the metal, and once with a substitute resin prosthesis inserted. Metal-affected CTs were processed using standard back-projection as well as projection interpolation (PI) MAR. Two experienced users segmented all lesions and compared segmentation accuracy. RESULTS: We achieved accurate delineation of periprosthetic lesions in the metal-free images. The presence of a metal implant led us to underestimate lesion volume and introduced geometrical errors in segmentation boundaries. Although PI MAR reduced streak artefacts, it led to greater underestimation of lesion volume and greater geometrical errors than without its application. CONCLUSION: CT metal artefacts impair image segmentation. PI MAR can improve subjective image appearance but causes loss of detail and lower image contrast adjacent to prostheses. Our experiments showed that PI MAR is counterproductive for manual segmentation of periprosthetic lesions and should be used with care.

Pediatric Supracondylar Humerus Fractures: Should We Avoid Surgery during After-Hours?

Pediatric supracondylar humerus fractures occur frequently. Often, the decision has to be made whether to operate immediately, e.g., during after-hours, or to postpone until office hours. However, the effect of timing of surgery on radiological and clinical outcomes is unclear. This literature review with the PICO methodology found six relevant articles that compared the results of office-hours and after-hours surgery for pediatric supracondylar humerus fractures. The surgical outcomes of both groups in these studies were assessed. One of the articles found a significantly higher "poor fixation rate" in the after-hours group, compared with office hours. Another article found more malunions in the "night" subgroup vs. the "all groups but night" group. A third article found a higher risk of postoperative paresthesia in the "late night" subgroup vs. the "day" group. Lastly, one article reported increased consultant attendance and decreased operative time when postponing to office hours more often. No differences were reported for functional outcomes in any of the articles. Consequently, no strong risks or benefits from surgical treatment during office hours vs. after-hours were found. It appears safe to postpone surgery to office hours if circumstances are not optimal for acute surgery, and if there is no medical contraindication. However, research with a higher level-of-evidence is needed make more definite recommendations.

AQUILA: assessment of quality in lower limb arthroplasty. An expert Delphi consensus for total knee and total hip arthroplasty.

BACKGROUND: In the light of both the importance and large numbers of case series and cohort studies (observational studies) in orthopaedic literature, it is remarkable that there is currently no validated measurement tool to appraise their quality. A Delphi approach was used to develop a checklist for reporting quality, methodological quality and generalizability of case series and cohorts in total hip and total knee arthroplasty with a focus on aseptic loosening. METHODS: A web-based Delphi was conducted consisting of two internal rounds and three external rounds in order to achieve expert consensus on items considered relevant for reporting quality, methodological quality and generalizability. RESULTS: The internal rounds were used to construct a master list. The first external round was completed by 44 experts, 35 of them completed the second external round and 33 of them completed the third external round. Consensus was reached on an 8-item reporting quality checklist, a 6-item methodological checklist and a 22-item generalizability checklist. CONCLUSIONS: Checklist for reporting quality, methodological quality and generalizability for case series and cohorts in total hip and total knee arthroplasty were successfully created through this Delphi. These checklists should improve the accuracy, completeness and quality of case series and cohorts regarding total hip and total knee arthroplasty.

A computed tomography based study on rotational alignment accuracy of the femoral component in total knee arthroplasty using computer-assisted orthopaedic surgery.

Rotation of the femoral component in total knee arthroplasty (TKA) is of high importance in respect of the balancing of the knee and the patellofemoral joint. Though it is shown that computer assisted surgery (CAOS) improves the anteroposterior (AP) alignment in TKA, it is still unknown whether navigation helps in finding the accurate rotation or even improving rotation. Therefore the aim of our study was to evaluate the postoperative femoral component rotation on computed tomography (CT) with the intraoperative data of the navigation system. In 20 navigated TKAs the difference between the intraoperative stored rotation data of the femoral component and the postoperative rotation on CT was measured using the condylar twist angle (CTA). This is the angle between the epicondylar axis and the posterior condylar axis. Statistical analysis consisted of the intraclass correlation coefficient (ICC) and Bland-Altman plot. The mean intraoperative rotation CTA based on CAOS was 3.5° (range 2.4-8.6°). The postoperative CT scan showed a mean CTA of 4.0° (1.7-7.2). The ICC between the two observers was 0.81, and within observers this was 0.84 and 0.82, respectively. However, the ICC of the CAOS CTA versus the postoperative CT CTA was only 0.38. Though CAOS is being used for optimising the position of a TKA, this study shows that the (virtual) individual rotational position of the femoral component using a CAOS system is significantly different from the position on a postoperative CT scan.

No improvement in long-term wear and revision rates with the second-generation Biomet cup (RingLoc) in young patients: 141 hips followed for median 12 years.

BACKGROUND: A number of excellent results with the cementless titanium femoral component of the Mallory Head Total Hip Replacement have been published. Unfortunately, these excellent results have been counteracted by the poor performance of the cementless titanium acetabular components. In 1994, the HexLoc acetabular component was replaced with a second-generation design, the RingLoc. We hypothesized that the new generation would have improved the results. METHODS: We retrospectively studied 111 consecutive patients (150 hips) younger than 55 years. Median follow-up time was 14 (6-18) years for the HexLoc and 10 (1-14) years for the RingLoc. 7 patients were lost to follow-up and 7 patients died. The 10-year survival rate, radiographic liner wear, and radiographic signs of prosthesis failure were compared between the 2 acetabular components. RESULTS: The Kaplan-Meier survival estimate with revision for any reason as the endpoint showed a 10-year survival of 89% (95% CI: 81-97) for the HexLoc and 92% (CI: 85-98) for the RingLoc. The mean annual wear rate for the HexLoc was 0.16 (SD 0.16) mm and it was 0.15 (0.1) mm for the RingLoc (p = 0.3). The radiographic signs of failure were equally distributed between the 2 groups. INTERPRETATION: Compared to the HexLoc type, the RingLoc system did not improve the mean percentage survival at 10 years; nor did it reduce the liner wear. Despite correction of the known design flaws in the HexLoc design, the RingLoc system did not show a clinically relevant improvement compared to its predecessor.

Elevated levels of numerous cytokines in drainage fluid after primary total hip arthroplasty.

As cytokines are involved in wound healing and other inflammatory processes, it could be valuable to measure their levels at the operative site. This study was conducted to investigate whether different cytokines are measurable in drainage fluid and, when measurable, whether we can find a difference in cytokine levels between one and six hours postoperatively. Samples from the drainage system in 30 consecutive patients undergoing primary total hip replacement were collected at one and six hours after closure of the wound. Levels of several cytokines were measured in the drainage fluids. A significant elevation of almost all cytokines was observed between the sample after one hour and six hours postoperatively. We found a strong correlation between the different pro-inflammatory cytokines. The IL-6 to IL-10 ratio were also raised, showing a pro-inflammatory predominance. Levels were much higher than those previously shown in serum.

Reconstructing the rheumatoid forefoot.

INTRODUCTION: The standard procedure when operating on the rheumatoid forefoot is resection arthroplasty of the metatarsophalangeal joints of the lesser rays. Good clinical results (with a follow-up of over 10 years) have been reported when this technique is used. Another technique is repositioning of the metatarsophalangeal subluxation or dislocation of the lesser rays. AIM: To assess the results of forefoot reconstruction using the repositioning technique performed in 54 feet (39 patients) by one surgeon using this technique. METHODS: 39 RA patients (15 bilateral, 54 feet) were treated with the technique of repositioning the metatarsophalangeal subluxation or dislocation. All surgery was performed by one orthopaedic surgeon. In case of severe deformity or degeneration of the metatarsophalangeal joint of the hallux, an arthrodesis was performed. All patients were reviewed after a mean follow-up of 40 months (range 12-72 months) and an American Orthopaedic Foot and Ankle Society (AOFAS) foot score, and Foot Function Index (FFI) were obtained. RESULTS: When, in addition to repositioning the metatarsophalangeal joints, an arthrodesis of the hallux was performed, the mean AOFAS-forefoot score was 69.80 (SD=11.8) at a mean of 40 months (SD=15.6 months) postoperatively. In cases with no operation on the hallux, the AOFAS score was 42.2 (SD=18.8) (p=0.001). The postoperative FFI-scores were 23.0 (SD=17.5) and 43.9 (SD=14.6) respectively (p=0.026). When comparing the patients who were satisfied (satisfaction VAS>7) and those who were not, the most important factor was also fusion of the first metatarsophalangeal (MPJ) joint, without a fusion only 50% was satisfied, with a fusion the satisfaction rate was 93%. In four patients a recurrence of the deformity of one of the lesser rays developed, for which a re-operation has been performed. CONCLUSIONS: Reconstruction of the rheumatoid forefoot by repositioning the metatarsophalangeal joints of the lesser rays, thereby preserving the joints, can be considered as a procedure that provides improvement in the clinical outcome. Best results were seen in patients in whom, in addition to reconstruction of the lesser rays, an arthrodesis of the hallux was performed.

No effect of ketoprofen and meloxicam on bone graft ingrowth: a bone chamber study in goats.

BACKGROUND AND PURPOSE: There is increasing awareness that non-steroidal anti-inflammatory drugs (NSAIDs), and especially the cyclooxygenase-2 (COX-2) selective ones, may retard bone healing. We have used NSAIDs (indomethacin for at least 7 days) to prevent heterotopic ossification after acetabular reconstructions using impacted bone grafts. The long-term clinical results have been satisfying, making it difficult to believe that there is an important negative effect of NSAIDs on graft incorporation. We studied the effect of two different NSAIDs on bone and tissue ingrowth in a bone chamber model in goats, using autograft, rinsed allograft, and allograft that had been rinsed and subsequently irradiated. METHODS: 9 goats received no NSAIDs, 9 received ketoprofen, and 9 received meloxicam--all for 6 weeks. In each goat 6 bone chambers were implanted: 2 filled with autograft, 2 with rinsed allograft, and 2 with allograft that had been rinsed and irradiated. The amount of bone ingrowth and total tissue ingrowth was compared between the groups. RESULTS: There were no statistically significant differences in bone ingrowth between the different groups. Also, no differences in bone ingrowth were found with respect to the type of graft used. Furthermore, there was no statistically significant difference in the total amount of ingrowth of fibrous tissue between the treatment groups. INTERPRETATION: No differences in bone ingrowth in titanium bone chambers could be detected with both ketoprofen and meloxicam compared to untreated control animals. This confirms our hypothesis that the effect of NSAIDs on the incorporation and ingrowth of bone graft is limited.

Lack of high BMI-related features in adipocytes and inflammatory cells in the infrapatellar fat pad (IFP).

BACKGROUND: Obesity is associated with the development and progression of osteoarthritis (OA). Although the infrapatellar fat pad (IFP) could be involved in this association, due to its intracapsular localization in the knee joint, there is currently little known about the effect of obesity on the IFP. Therefore, we investigated cellular and molecular body mass index (BMI)-related features in the IFP of OA patients. METHODS: Patients with knee OA (N = 155, 68% women, mean age 65 years, mean (SD) BMI 29.9 kg/m2 (5.7)) were recruited: IFP volume was determined by magnetic resonance imaging in 79 patients with knee OA, while IFPs and subcutaneous adipose tissue (SCAT) were obtained from 106 patients undergoing arthroplasty. Crown-like structures (CLS) were determined using immunohistochemical analysis. Adipocyte size was determined by light microscopy and histological analysis. Stromal vascular fraction (SVF) cells were characterized by flow cytometry. RESULTS: IFP volume (mean (SD) 23.6 (5.4) mm3) was associated with height, but not with BMI or other obesity-related features. Likewise, volume and size of IFP adipocytes (mean 271 pl, mean 1933 µm) was not correlated with BMI. Few CLS were observed in the IFP, with no differences between overweight/obese and lean individuals. Moreover, high BMI was not associated with higher SVF immune cell numbers in the IFP, nor with changes in their phenotype. No BMI-associated molecular differences were observed, besides an increase in TNFα expression with high BMI. Macrophages in the IFP were mostly pro-inflammatory, producing IL-6 and TNFα, but little IL-10. Interestingly, however, CD206 and CD163 were associated with an anti-inflammatory phenotype, were the most abundantly expressed surface markers on macrophages (81% and 41%, respectively) and CD163+ macrophages had a more activated and pro-inflammatory phenotype than their CD163- counterparts. CONCLUSIONS: BMI-related features usually observed in SCAT and visceral adipose tissue could not be detected in the IFP of OA patients, a fat depot implicated in OA pathogenesis.

Prophylaxis for heterotopic ossification after primary total hip arthroplasty. A cohort study between indomethacin and meloxicam.

The authors have conducted a prospective cohort study of the efficacy of a 7 days administration of Indomethacin (n = 89) versus Meloxicam (n = 92), in the prophylaxis of heterotopic ossification (HO) in primary total hip arthroplasty. To assess the interobserver variability of the Brooker classification, all radiographs were evaluated by three investigators. In the Indomethacin group 25 patients developed HO (grade I: 22, grade III: 2 and grade IV: 1). In the Meloxicam group 34 developed HO (grade I: 30, grade II: 1 and grade III: 3). We were not able to show any difference between Indomethacin and Meloxicam in preventing heterotopic ossification after primary hip arthroplasty. We found a high interobserver variability in the grading system according to Brooker, in particular for the higher grades(grade II, III and IV).

[Haematogenous infection of a prosthetic joint]. / Hematogene infectie van een gewrichtsprothese: kleine wondjes met grote gevolgen.

Prosthetic joint infection (PJI) is a major complication after total joint arthroplasty. The most common source of these PJIs is a wound infection immediately after implantation of the artificial joint; however, haematogenous infection is also a common source of PJIs. We describe 3 patients, all suffering from (rheumatoid) arthritis, who presented at the emergency department with a wound on the foot or ankle and a swollen and painful prosthetic knee joint, which was functioning well for a long period of time (6 months to 5 years). All patients had several debridements of their infected total knee arthroplasty with local and systemic antibiotics. Patient outcome was widely diverse: from death to successful treatment. These case descriptions are good examples of the different outcomes from a major complication after a small wound. Care should be taken particularly for wounds around the foot and ankle in patients with a total joint arthroplasty, especially those who also have diabetes, rheumatoid arthritis or are immunocompromised.

Comparison of Ho:YAG laser and coblation for interface tissue removal in minimally invasive hip refixation procedures.

Aseptic loosening is the major failure mode for hip prostheses. Currently, loosened prostheses are revised during open surgery. Because of a high complication rate, this demanding procedure cannot be performed in patients with a poor general health. We are developing an alternative minimally invasive refixation procedure that leaves the prostheses in place, but relies on removing the interface membrane and replacing it with bone cement. The aim of this study was to evaluate two interface tissue removal techniques - Ho:YAG laser and coblation - based on two criteria: thermal damage and the ablation rate. In vitro a loosened hip prosthesis was simulated by implanting a prosthesis in each of 10 cadaver femora. Artificially created peri-prosthetic lesions were filled with chicken liver as an interface tissue substitute. We measured temperatures in vitro at different radial distances from the site of removal. Temperatures during removal were recorded both inside the interface tissue and in the surrounding bone. This study demonstrated that temperatures generated in the bone do not result in thermal damage (increasing less than 10°C relative to body temperature). Temperatures inside the interface tissue are sufficiently high to destroy the interface tissue (T>50°C, duration>1 min). Using laser instead of coblation for the removal of interface tissue resulted in higher temperatures - thus a faster removal of interface tissue. This is in accordance with the ablation rate test. Ho:YAG laser is advantageous compared to coblation. We consider Ho:YAG laser a promising tool for interface tissue removal.

Regenerative potential of human muscle stem cells in chronic inflammation.

INTRODUCTION: Chronic inflammation is a profound systemic modification of the cellular microenvironment which could affect survival, repair and maintenance of muscle stem cells. The aim of this study was to define the role of chronic inflammation on the regenerative potential of satellite cells in human muscle. METHODS: As a model for chronic inflammation, 11 patients suffering from rheumatoid arthritis (RA) were included together with 16 patients with osteoarthritis (OA) as controls. The mean age of both groups was 64 years, with more females in the RA group compared to the OA group. During elective knee replacement surgery, a muscle biopsy was taken from the distal musculus vastus medialis. Cell populations from four RA and eight OA patients were used for extensive phenotyping because these cell populations showed no spontaneous differentiation and myogenic purity greater than 75% after explantation. RESULTS: After mononuclear cell explantation, myogenic purity, viability, proliferation index, number of colonies, myogenic colonies, growth speed, maximum number of population doublings and fusion index were not different between RA and OA patients. Furthermore, the expression of proteins involved in replicative and stress-induced premature senescence and apoptosis, including p16, p21, p53, hTERT and cleaved caspase-3, was not different between RA and OA patients. Mean telomere length was shorter in the RA group compared to the OA group. CONCLUSIONS: In the present study we found evidence that chronic inflammation in RA does not affect the in vitro regenerative potential of human satellite cells. Identification of mechanisms influencing muscle regeneration by modulation of its microenvironment may, therefore, be more appropriate.

Total ankle prostheses in rheumatoid arthropathy: Outcome in 52 patients followed for 1-9 years.

BACKGROUND AND PURPOSE: The first generations of total ankle replacements (TARs) showed a high rate of early failure. In the last decades, much progress has been made in the development of TARs, with the newer generation showing better results. We evaluated TARs implanted with rheumatoid arthritis (RA) or juvenile inflammatory arthritis (JIA) as indication. PATIENTS AND METHODS: 58 total ankle prostheses (Buechel-Pappas and STAR type) were implanted in patients with RA (n = 53) or JIA (n = 5) in 54 patients (4 bilateral). After a mean followup of 2.7 (1-9) years, all patients were reviewed by two orthopedic surgeons who were not the surgeons who performed the operation. Standard AP and lateral radiographs were taken and a Kofoed ankle score was obtained; this is a clinical score ranging from 0-100 and consists of sub-scores for pain, disability, and range of motion. RESULTS: 2 patients died of unrelated causes. Of the 52 patients who were alive (56 prostheses), 51 implants were still in place and showed no signs of loosening on the most recent radiographs. The mean Kofoed score at follow-up was 73 points (SD 16, range 21-92). 4 patients showed a poor result (score < 50) with persistent pain for which no obvious reason could be found. 5 implants were removed, 4 because of infection and 1 because of aseptic loosening. INTERPRETATION: Medium-term results of the STAR and BP types of TAR in RA were satisfactory. The main reason for failure of the implant was infection.