Long-term follow-up results of primary and recurrent pigmented villonodular synovitis.

OBJECTIVE: Adequate documentation of the outcome of treatment of pigmented villonodular synovitis (PVNS) is sparse. Available case series show relatively short follow-up times and often combine locations or subtypes to increase patient numbers. This article describes the long-term follow-up of a single institution's large consecutive series of PVNS. METHODS: Retrospectively, 107 PVNS patients were identified between 1985 and 2011 by searching pathology and radiology records. Treatment complications, recurrences and quality of life were evaluated. Most patients (85.2%) were primarily or secondarily treated at our institution. RESULTS: Both subtypes, localized PVNS [29 (27%)] and diffuse PVNS [75 (70%)] were represented. The knee was affected in 88% of patients. Treatments received were surgery, external beam radiotherapy, radiosynovectomy, targeted therapy, immunotherapy or combinations of these. Forty-nine (46%) patients had prior treatment elsewhere. The mean follow-up from diagnosis until last contact was 7.0 years (range 0.3-27.4) for localized PVNS and 14.5 years (range 1.1-48.7) for diffuse PVNS. The 1- and 5-year recurrence-free survival rates for diffuse PVNS were 69% and 32%, respectively. Quality of life, estimated by 36-item Short Form Health Survey (SF-36) scores, were not significantly different between localized and diffuse PVNS. However, both patient groups scored lower than the general population norms on the general health component (59.2 and 56.3, respectively, P < 0.05). CONCLUSION: Recurrence rates of PVNS increase with time. Long-term follow-up shows, particularly in diffuse PVNS, it is a continually recurring problem, and over time it becomes increasingly difficult to cure. The quality of life is decreased in patients with PVNS compared with the general population.

Pigmented villonodular synovitis: current concepts about diagnosis and management.

At present, the treatment strategies in patients with localized and diffuse forms of pigmented villonodular synovitis have more or less been standardized. However, these strategies are not optimal because high recurrence rates persist and studies with a sufficient level of evidence are lacking. This systematic review article describes all known treatment options for intra-articular pigmented villonodular synovitis and their clinical results. Based on this research, we provide guidelines to support physicians in making the optimal treatment decisions. Given the rarity of the disease, randomized studies are not to be expected, but an international registry through existing networks would offer the benefit of getting a better insight into the outcome of this disease. Therefore, we propose a basic set of data to be investigated and ideally to be reported on in such a registry.

Long-term results of cemented total hip arthroplasty in patients younger than 30 years and the outcome of subsequent revisions.

BACKGROUND: The number of total hip arthroplasties in patients under 30 years is increasing over the years. Almost all of them will face at least one or more future revisions in their life. Therefore, the implant used should have a high survival rate, and needs to be easily revisable resulting in a low re-revision rate. Several studies have evaluated the outcome of total hip arthroplasties in patients under 30 years. However, only a few reported on the follow-up outcome of 10 years or more. In addition, none of these reports published data of the subsequent revisions of these implants within their original report. METHODS: We studied historically prospective collected data of 48 consecutive patients (69 hips) younger than 30 years, treated with a cemented primary total hip prosthesis between 1988 and 2004. Since the last evaluation of this cohort, two patients were lost to follow-up. For all hip revisions in this cohort, again cemented implants were used, mostly in combination with bone impaction grafting. Kaplan-Meier survival curves at 10- and 15 years for the primary total hip arthroplasties and revisions were determined. RESULTS: The mean age at time of primary surgery was 25 years (range, 16 to 29 years). Mean follow-up of the primary hips was 11.5 years (range, 7 to 23 years). During follow-up 13 revisions were performed; in 3 cases a two-stage total revision was performed for septic loosening and 9 cups were revised for aseptic loosening. There were no aseptic stem revisions. The 10 and 15-year survival rates with endpoint revision for aseptic loosening of the primary total hip were 90% (95% CI: 79 to 96) and 82% (95% CI: 65 to 92) respectively. None of our 13 subsequent revisions needed a re-revision within 10 years after re-implantation. CONCLUSIONS: Cemented total hip implants in patients under 30 years have an encouraging outcome at 10 and 15 years after surgery in these young patients. The 13 revised hips, treated with bone grafting and the third generation cement technique, were performing well with no re-revisions within ten years after surgery.

Good results with cemented total hip arthroplasty in patients between 40 and 50 years of age.

BACKGROUND AND PURPOSE: Total hip arthroplasties in young patients have lower long-term survival rates than in older patients. We evaluated the use of a unique treatment protocol in patients aged between 40 and 50 years. In all cases we used a cemented THA, and for acetabular deficiencies we also used impacted bone grafts together with a cemented cup. METHODS: In 140 consecutive patients who were between 40 and 50 years of age at index surgery, 168 cemented total hip prostheses were evaluated after a mean follow-up time of 10 (2-19) years. Acetabular deficiencies were reconstructed with wire meshes and impacted bone grafts with a cemented cup (70 hips). During follow-up, 18 patients died (27 hips); in this group 3 hips (3 patients) had been revised. None of the patients were lost to follow-up. In all surviving patients, clinical assessment was performed with hip-score questions and all radiographs were evaluated. RESULTS: All clinical questionnaires showed an improved clinical hip score. 29 hips (17%) were revised after a mean of 8 (0.3-18) years. Kaplan-Meier survival analysis showed a survival of 88% (95% CI: 82-94) after 10 years with revision of either component for any reason. Survival with endpoint revision for aseptic loosening of either component was 94% (95% CI: 90-99) after 10 years. INTERPRETATION: Cemented implants in young patients have satisfying long-term results. Reconstruction of acetabular deficiencies with impacted bone grafts show promising results.

Cemented polyethylene cups in patients younger than 40 years.

UNLABELLED: Although uncemented cup implants frequently are used in young patients, we believe long-term survival rates of cups in these patients are somewhat disappointing, and therefore we have continued to use cemented cups in primary THA, even in young patients. However, in cases of acetabular bone stock defects, we also use bone impaction grafting. We prospectively followed 130 patients with 175 cemented cups; no patients were lost to followup. The mean age of the patients at surgery was 31 years (range, 16-39 years). An acetabular reconstruction with bone impaction grafting was performed in 84 hips (48%). The minimum followup was 2 years (average, 8.1 years; range, 2.0-18.5 years). Twenty-one of the 175 cups (12%) were revised at an average of 8.1 years (range, 2.0-18.5 years). Reasons for revision were infection (one early, seven late), recurrent dislocations (two), traumatic loosening (one), and aseptic loosening (10). The 10-year survival rate of all cemented cups with end point of revision for any cause was 85%. Survival with end point of aseptic loosening of all cups was 92%. Survival with end point of revision for aseptic loosening was 90% for the cups without impaction grafting and 95% for the cups with impaction grafting. We believe cemented acetabular cups in young patients have acceptable midterm survival; however, in the case of acetabular bone defects, we recommend reconstruction with impaction grafting. LEVEL OF EVIDENCE: Level III, therapeutic study.

The stability of impacted morsellized bone grafts in a metal cage under dynamic loaded conditions: an in vitro reconstruction of a segmental diaphyseal bone defect.

INTRODUCTION: Reconstructions of segmental diaphyseal bone defects with massive allografts are related to complications like nonunion and fractures. A reconstruction of these defects with a cage filled with an impacted morsellized bone graft could be an alternative. The bone graft in these cages should ideally be loaded to prevent resorption. Loading of morsellized bone grafts however can cause instability. The goal of this study was to assess the stability of an impacted morsellized bone graft in a cage under dynamic loaded conditions in an in vitro reconstruction of a segmental diaphyseal bone defect. The second goal was to assess the influence of cage type, washing of the graft and bone-cage fit. MATERIALS AND METHODS: Two different cage types were filled with impacted morsellized bone graft. The grafts were used washed and unwashed and in variable bone-cage fit conditions. We recorded the bone graft deformation in the cage under dynamic loaded conditions. RESULTS: Stability appeared to be not very sensitive to the cage type and whether the bone chips were washed or not. However, quality of the fit of the cage with the bone segment was an important parameter and should be optimized during surgery. CONCLUSIONS: Morsellized impacted bone graft in a cage is stable in dynamic loaded conditions in an in vitro reconstruction of a segmental diaphyseal bone defect. We believe that this method of reconstruction is a promising alternative for the reconstruction of large diaphyseal bone defects and should be tested relative to its biological merits in animal experiments.

Replacement of the knee meniscus by a porous polymer implant: a study in dogs.

BACKGROUND: Meniscectomy will lead to articular cartilage degeneration in the long term. Therefore, the authors developed an implant to replace the native meniscus. HYPOTHESIS: The porous polymer meniscus implant develops into a neomeniscus and protects the cartilage from degeneration. STUDY DESIGN: Controlled laboratory study. METHODS: In a dog model, a porous polymer scaffold with optimal properties for tissue infiltration and regeneration of a neomeniscus was implanted and compared with total meniscectomy. The tissue infiltration and redifferentiation in the scaffold, the stiffness of the scaffold, and the articular cartilage degeneration were evaluated. RESULTS: Three months after implantation, the implant was completely filled with fibrovascular tissue. After 6 months, the central areas of the implant contained cartilage-like tissue with abundant collagen type II and proteoglycans in their matrix. The foreign-body reaction remained limited to a few giant cells in the implant. The compression modulus of the implant-tissue construct still differed significantly from that of the native meniscus, even at 6 months. Cartilage degeneration was observed both in the meniscectomy group and in the implant group. CONCLUSION: The improved properties of these polymer implants resulted in a faster tissue infiltration and in phenotypical differentiation into tissue resembling that of the native meniscus. However, the material characteristics of the implant need to be improved to prevent degeneration of the articular cartilage. CLINICAL RELEVANCE: The porous polymer implant developed into a polymer-tissue construct that resembled the native meniscus, and with improved gliding characteristics, this prosthesis might be a promising implant for the replacement of the meniscus.

Assessment of tissue ingrowth rates in polyurethane scaffolds for tissue engineering.

The continuous development of new biomaterials for tissue engineering and the enhancement of tissue ingrowth into existing scaffolds, using growth factors, create the necessity for developing adequate tools to assess tissue ingrowth rates into porous biomaterials. Current histomorphometric techniques evaluating rates of tissue ingrowth tend either to measure the overall tissue content in an entire sample or to depend on the user to indicate a front of tissue ingrowth. Neither method is particularly suitable for the assessment of tissue ingrowth rates, as these methods either lack the sensitivity required or are problematic when there is a tissue ingrowth gradient rather than an obvious tissue ingrowth front. This study describes a histomorphometric method that requires little observer input, is sensitive, and renders detailed information for the assessment of tissue ingrowth rates into porous biomaterials. This is achieved by examining a number of computer-defined concentric zones, which are based on the distance of a pixel from the scaffold edge. Each zone is automatically analyzed for tissue content, eliminating the need for user definition of a tissue ingrowth front and thus reducing errors and observer dependence. Tissue ingrowth rates in two biodegradable polyurethane scaffolds (Estane and polycaprolactone-polyurethane [PCLPU]) specifically designed for tissue engineering of the knee meniscus were assessed. Samples were subcutaneously implanted in rats with follow-up until 6 months. Especially at the earlier follow-up points, PCLPU scaffolds showed significantly higher tissue ingrowth rates than Estane scaffolds, making the PCLPU scaffold a promising candidate for further studies investigating meniscus tissue engineering.

Tissue ingrowth and degradation of two biodegradable porous polymers with different porosities and pore sizes.

Commonly, spontaneous repair of lesions in the avascular zone of the knee meniscus does not occur. By implanting a porous polymer scaffold in a knee meniscus defect, the lesion is connected with the abundantly vascularized knee capsule and healing can be realized. Ingrowth of fibrovascular tissue and thus healing capacity depended on porosity, pore sizes and compression modulus of the implant. To study the lesion healing potential, two series of porous polyurethanes based on 50/50 epsilon-caprolactone/L-lactide with different porosities and pore sizes were implanted subcutaneously in rats. Also, in vitro degradation of the polymer was evaluated. The porous polymers with the higher porosity, more interconnected macropores, and interconnecting micropores of at least 30 microm showed complete ingrowth of tissue before degradation had started. In implants with the lower macro-porosity and micropores of 10-15 microm degradation of the polymer occurred before ingrowth was completed. Directly after implantation and later during degradation of the polymer, PMN cells infiltrated the implant. In between these phases the foreign body reaction remained restricted to macrophages and giant cells. We can conclude that both foams seemed not suited for implantation in meniscal reconstruction while either full ingrowth of tissue was not realized before polymer degradation started or the compression modulus was too low. Therefore, foams must be developed with a higher compression modulus and more connections with sufficient diameter between the macropores.

Cross-linked type I and type II collagenous matrices for the repair of full-thickness articular cartilage defects--a study in rabbits.

The physico-chemical properties of collagenous matrices may determine the tissue response after insertion into full-thickness articular cartilage defects. In this study, cross-linked type I and type II collagen matrices, with and without attached chondroitin sulfate, were implanted into full-thickness defects in the femoral trochlea of adolescent rabbits. The tissue response was evaluated 4 and 12 weeks after implantation by general histology and two semi-quantitative histological grading systems. Four weeks after implantation, type I collagenous matrices were completely filled with cartilage-like tissue. By contrast, type II collagenous matrices revealed predominantly cartilaginous tissue only at the superficial zone and at the interface of the matrix with the subchondral bone, leaving large areas of the matrix devoid of tissue. Attachment of chondroitin sulfate appeared to promote cellular ingrowth and cartilaginous tissue formation in both types of collagen matrices. Twelve weeks after implantation, the differences between the matrices were less pronounced. The deep parts of the subchondral defects were largely replaced by new bone with a concomitant degradation of the matrices. The original cartilage contours in defects with type I collagen-based matrices were repaired with fibro-cartilaginous tissue. Defects containing type II matrices showed an increase in the amount of superficial cartilage-like tissue. The original contour, however, was not completely restored in all animals, occasionally leaving a central depression or fissure. It is concluded that different types of collagen matrices induce different tissue responses in full-thickness articular cartilage defects. Type I collagen-based matrices are superior to guide progenitor cells from a subchondral origin into the defect. In type II collagen-based matrices cell migration is less, but invading cells are directed into a chondrocyte phenotype. Based on these observations it is suggested that a composite matrix consisting of a deep layer of type I collagen and a more superficial layer of type II collagen may be the matrix of choice for cartilage regeneration.

Fatigue after treatment for malignant and benign bone and soft tissue tumors.

Fatigue has been mentioned as an important complaint in several groups of disease-free patients after curative treatment for cancer. However, it has never been investigated in a sample of patients who have been treated for a bone or soft tissue tumor in the past. In the current study, these patients participated. Measurement included posted questionnaires at baseline and at follow-up (two years later). Baseline results indicated that fatigue is a severe problem for 28% of the investigated patients. Percentages were equal for patients who were treated for malignant or benign tumors. Fatigue complaints seem to be most severe for patients who finished treatment relatively recently, and for patients who had to undergo more than one operation. In addition, fatigue was associated with several psychological and physical variables. At follow-up, the majority of all patients who were severely fatigued at baseline continued to be severely fatigued. Severe fatigue at follow-up was predicted by oncological complications after initial treatment, less optimism, and more somatization. It can be concluded that fatigue is an important problem for more than a quarter of a sample of patients who have been treated for a malignant or benign bone or soft tissue tumor in the past.

Acetabular revision with impacted morselized cancellous bone graft and a cemented cup in patients with rheumatoid arthritis: three to fourteen-year follow-up.

BACKGROUND: Acetabular revision in patients with rheumatoid arthritis is often difficult because of the poor quality and quantity of the acetabular bone stock. The purpose of this study was to evaluate the midterm clinical and radiographic outcomes of acetabular revision with use of an impaction bone-grafting technique and a cemented polyethylene cup. METHODS: Thirty-five consecutive acetabular revisions were performed with impaction bone-grafting and use of a cemented cup in twenty-eight patients with rheumatoid arthritis. The average age at the revision was fifty-seven years. The minimum duration of follow-up of all reconstructions that were still functioning or that were followed until the time of death was three years (mean, 7.5 years; range, three to fourteen years). No patient was lost to follow-up, but five patients (six hips) died before the time of the review. The acetabular bone defects were classified as cavitary in twelve hips and as combined segmental-cavitary in twenty-three. RESULTS: The five patients (six hips) who died had been doing well at the time of their latest follow-up. Of the remaining patients, six (six hips) had a repeat revision. The average Harris hip score of the living patients with a surviving implant at the time of follow-up was 82 points, and there was no or only mild pain in twenty-one of the twenty-three hips. Radiographic analysis of all twenty-nine hips that had not been revised showed loosening in one hip and a nonprogressive radiolucent line in one zone in two others. Kaplan-Meier analysis demonstrated a prosthetic survival rate, with aseptic loosening as the end point, of 90% at eight years. CONCLUSION: Acetabular revision with impaction bone-grafting and a cemented cup in patients with rheumatoid arthritis had acceptable results at an average of 7.5 years postoperatively.

High fatigue scores before and after surgical treatment of bone and soft tissue tumors.

The first objective of the present study was to investigate fatigue severity in patients diagnosed with bone and soft tissue tumors prior to the surgical treatment of the tumor and 6 months post-operatively. The second objective was to determine which variables are associated with severe fatigue. Patients diagnosed with benign or low-grade malignant bone and soft tissue tumors, undergoing surgical therapy for the tumor only, were included in this study. The control group contained patients scheduled for knee arthroscopy for suspected meniscus tears. Fatigue, pain, anxiety and self-efficacy were measured pre-operatively and after 6 months and each patient wore an actometer to quantify physical activity. In the tumor group of 43 patients, 35% were severely fatigued pre-operatively and 33% post-operatively. The tumor group reported a significantly higher level of anxiety. No differences were observed in pain, physical limitations, self-efficacy or actometer scores. Multiple regression analysis of the tumor group revealed that higher pain scores, higher state anxiety and lower self-efficacy were asssociated with fatigue severity. In the control group of 24 knee arthroscopy patients, the percentage of severely fatigued patients decreased from 38% (n=9) prior to treatment to 29% (n=7) 6 months later. A substantial number of patients were severely fatigued in both the tumor group and the knee arthroscopy group. Self-efficacy, pain and anxiety appear to be the most important variables associated with fatigue severity in tumor patients prior to surgery.

[Hip resurfacing in patients under 55 years of age]. / De resurfacing heupprothese bij patiënten jonger dan 55 jaar.

Hip resurfacing arthroplasty was introduced as an alternative to the conventional total hip arthroplasty which had shown suboptimal results in younger patients. Application of the resurfacing technique in younger patients has increased over the last few years. To date, no randomized controlled trials with a minimum follow-up span of 10 years comparing hip resurfacing to conventional hip replacement have been conducted in patients under 55 years of age. Australian and English hip registries demonstrate high revision rates after 5 years for some brands of resurfacing implants. In addition to these disappointing revision rates, the complication of aseptic lymphocytic vasculitis caused by metal particles evoking a local tissue reaction has been increasingly reported. The resurfacing procedure recently received some negative media attention in the Netherlands, leading to confusion among patients. In order to ease patient doubts, it is important to correctly inform them as to the type of implant used, for example, by means of the website or an information card.

Total hip arthroplasties in young patients under 50 years: limited evidence for current trends. A descriptive literature review.

We examined all reported outcomes of uncemented and cemented total hip arthroplasty in patients younger than 50 years of age listed in Medline (1966- 1 January 2009) and PubMed, and scrutinised reference lists of relevant papers. In addition, we evaluated relevant data in the Swedish hip arthroplasty register. 109 relevant articles were identified, 37 of which had a mean follow-up longer than 10 years. Although uncemented implants are widely used in patients under 50 years of age, there are only 2 reports that fulfil the criteria published by the National Institute for Clinical Excellence (NICE) in the United Kingdom (follow-up of >10 yrs and survival of =90%). Current trends relating to implant selection remain unsupported by survival data, and additional information about the long-term results of newer implants is essential. As matters stand, the most reliable results relate to cemented implants.

Percutaneous radiofrequency ablation of osteoid osteomas with use of real-time needle guidance for accurate needle placement: a pilot study.

PURPOSE: To evaluate the accuracy and technical success of positioning a radiofrequency ablation (RFA) electrode in osteoid osteomas by use of a new real-time needle guidance technology combining cone-beam computed tomography (CT) and fluoroscopy. MATERIALS AND METHODS: Percutaneous RFA of osteoid osteomas was performed in five patients (median age 18 years), under general anesthesia, with the use of cone-beam CT and fluoroscopic guidance for electrode positioning. The outcome parameters were technical success, meaning correct needle placement in the nidus; accuracy defined as the deviation (in mm) from the center of the nidus; and clinical outcome at follow-up. RESULTS: In all five cases, positioning was possible within 3 mm of the determined target location (median nidus size 6.8 mm; range 5-10.2 mm). All procedures were technically successful. All patients were free of pain at clinical follow-up. No complications were observed. CONCLUSION: Real-time fluoroscopy needle guidance based on cone-beam CT is a useful tool to accurately position radiofrequency needles for minimally invasive treatment of osteoid osteomas.

[Total hip arthroplasty in patients under 40 years of age and, if indicated, reconstruction of acetabular defects with bone impaction grafting]. / Totaleheupprothesen bij patiënten jonger dan 40 jaar en reconstructie van botdefecten met botsnippers.

OBJECTIVE: To determine the long-term results of primary cemented total hip arthroplasty in patients under the age of 40. In cases of acetabular defects, initial reconstruction with bone impaction grafting was performed. DESIGN: Cohort analysis. METHODS: Details of patients under the age of 40 who underwent primary cemented total hip arthroplasty between 1 January 1988 and 30 June 2004 were analysed. The primary goal of this study was to determine the time until revision surgery. Kaplan Meier analysis was used to calculate prosthesis survival. RESULTS: A total of 175 total hip arthroplasties in 130 patients were included in the study. Acetabular reconstruction using bone impaction grafting was performed on 84 hips (48%). The average age at surgery was 31 years. Six patients (8 hips) died during follow-up; none of these had undergone revision surgery. Average follow-up was 8.1 years (range: 2.0-18.5). In total, 24 hips (14%) were revised. Reasons for revision were: septic loosening (n = 8), recurrent dislocations (n = 4), traumatic loosening (n = 1) and aseptic loosening (n = 11). The 10-year prosthesis survival was 83% (95% CI: 76-90) with the endpoint 'revision for any reason' and 92% (95% CI: 86-98) with the endpoint 'revision for aseptic loosening'. Aseptic survival of the cups with and without bone impaction grafting was 95% (95% CI: 89-100) and 90% (95% CI: 81-99) (p = 0.73), respectively. CONCLUSION: Hip replacement with cemented total hip arthroplasty in patients under the age of 40 produced good long-term results. Acetabular deficiencies reconstructed with bone impaction grafting also produced good results in this group of patients.

Methodological systematic review: mortality in elderly patients with cervical spine injury: a critical appraisal of the reporting of baseline characteristics, follow-up, cause of death, and analysis of risk factors.

STUDY DESIGN: Methodologic systematic review. OBJECTIVE: To determine the validity of reported risk factors for mortality in elderly patients with cervical spine injury. SUMMARY OF BACKGROUND DATA: In elderly patients with cervical spine injury, mortality has frequently been associated with the type of treatment. To date, however, no review evaluating the validity of reported risk factors for mortality in elderly patients with cervical spine injury has been published. METHODS: Studies evaluating the treatment of cervical spine injuries in elderly (>/=60 years of age) patients were searched through the Medline and EMBASE databases. In addition to standard methodologic details, reporting of putative confounding baseline characteristics and analysis of risk factors for mortality were appraised critically. For this purpose, patient data presented in included studies were pooled. Exploratory descriptive statistics were used for data analysis. RESULTS: Twenty-six eligible studies were identified, including a total of 1550 pooled elderly subjects. Except for 2, all studies reported presence or absence of spinal cord injury. Details concerning the severity and/or extent of the injury were reported in 12 (46%) studies. Pre-existing comorbidities were reported in 9 studies (35%). In the pooled subjects, the cause of death was not reported in 155 of 335 deceased patients (42%). Based on own results, 18 (69%) studies reported on risk factors for mortality. Of these studies, 6 (23%) performed statistical analyses of risk factors for mortality outcomes. Only 1 study statistically adjusted potential risk factors for mortality for confounding. CONCLUSION: Overall, pre-existing comorbidities, concomitant injuries, follow-up and cause of death have been underreported in studies investigating the treatment of cervical spine injuries in elderly patients. To strengthen the validity of risk factors for mortality in future clinical trials, adjustments for appropriately reported putative confounders by regression analysis are mandatory.

Acetabular revision with impacted morselized cancellous bone graft and a cemented cup in patients with rheumatoid arthritis. A concise follow-up, at eight to nineteen years, of a previous report.

We previously reported our results at a minimum of three years after thirty-five revisions of total hip arthroplasty acetabular components in twenty-eight patients with rheumatoid arthritis. The revisions were performed with use of impacted morselized bone graft and a cemented cup. This update report presents the results at eight to nineteen years after the surgery, which, to our knowledge, is the longest follow-up available in the literature. No patient was lost to follow-up. Since our previous report, there were two additional cup failures due to aseptic loosening, at ten and sixteen years postoperatively. Kaplan-Meier analysis showed the probability of survival of the acetabular component at twelve years to be 80% (95% confidence interval, 65% to 95%) with removal of the cup for any reason as the end point and 85% (95% confidence interval, 71% to 99%) with aseptic loosening as the end point. Cup revisions performed with cement and use of impaction bone-grafting in patients with rheumatoid arthritis led to acceptable long-term prosthetic survival rates. This technique is attractive from a biological standpoint because of the possibility of maintaining acetabular bone stock.

Metastatic potential of an aneurysmal bone cyst.

Aneurysmal bone cysts (ABCs) are benign bone tumors consisting of blood-filled cavities lined by connective tissue septa. Recently, the hypothesis that ABCs are lesions reactive to local hemodynamics has been challenged after the discovery of specific recurrent chromosomal abnormalities. Multiple cases of malignant transformation of ABC into (osteo)sarcoma have been described, as well as a number of cases of telangiectatic osteosarcoma which had been misdiagnosed as ABC. We herewith document a case of a pelvic ABC metastatic to the lung, liver, and kidneys. Diagnosis was confirmed by the presence of a break in the USP6 gene, which is pathognomonic for ABC, in a pulmonary metastasis of our patient. Sarcomatous transformation as an explanation for this behavior was ruled out by demonstrating diploid DNA content in both the pulmonary lesion and the primary tumor.