Titanium modular stems in total hip arthroplasty due to developmental dysplasia: a registry comparison with single-taper implants.

INTRODUCTION: The routine use of proximal femoral modularity was discouraged in total hip arthroplasties (THAs). However, titanium dual-taper (DT) implants may provide some advantages over single-taper (ST) stems in cases of complex deformity. A registry study comparing ST and DT stems in dysplasia was designed, aiming to assess: (1) survival rates at long-term; (2) reasons for revision; (3) the profile of failed implants. METHODS: The arthroplasty registry RIPO was investigated for cementless THAs performed for dysplasia since 2000. ST implants were compared to titanium-on-titanium DT stems. Demographics and implant features were collected. Survival rates and reasons for revision were compared. The profile of DT stem failures in dysplasia was defined. RESULTS: 6429 implants were included in the study, 3642 ST and 2787 DT. The demographic and implant features of the 2 cohorts were not comparable. The DT cohort achieved higher survival rates at long-term (93.9% vs. 91.6%, p = 0.018). DT implants showed a higher rate of implant breakage (0.6%, p = 0.011) and a lower rate of aseptic loosening (p = 0.005). There were no differences in terms of revisions for dislocation. No metallosis occurred. There were more revisions in DT implants in males <65 years, with a 28-mm head size or smaller. CONCLUSIONS: Modularity did not result in lower survival rates in dysplastic patients and may even reduce the rate of aseptic loosening in comparison to ST stems. The rate of implant breakage is not negligible. Younger males are not good candidates for titanium DT stems.

One-stage complete eradication and revision hip due to pseudotumor in metal-on-metal hip arthroplasty.

Background: The correct management and treatment of pseudotumors due to metal-on-metal (MOM) hip arthroplasty are still debated. The purpose of this study is to analyze the surgical treatment and the clinical and radiographic 3-year outcomes of MOM arthroplasty revisions due to pseudotumor treated with a strategy of excision and revision. Methods: Consecutive, retrospective series of 21 patients (8 males/13 females) with pseudotumor due to MOM hip arthroplasty was surgically treated at a single tertiary center. Demographic, clinical, radiological and implant-related features were collected pre-operatively. Post-revision clinical and radiographic parameters were evaluated. Chromium (Cr) and cobalt (Co) blood samples were collected before and after surgery. Results: Three patients (14.2%) with pseudotumor underwent a resection arthroplasty due to infection (perioperative finding) and could not be reimplanted due to septic relapses. Twenty (95.2%) pseudotumors were completely resected. Revisions [2 total hip reimplantations (11.1%) and 16 isolated component revisions (88.9%)] were performed with non-MOM couplings. A clinical improvement at a mean post-revision follow-up 3.3 years [standard deviation (SD), ±2.2 years] was observed, from 50.3 (SD, ±4.6) to 88.3 (SD, ±9.2) Harris hip score (HHS) points (P<0.001). Among revisions, there were 5 complications (23.8%): 1 dislocation, 1 psoas impingement, and 3 infections (14.2%). No re-revision was carried out. Three (14.2%) pseudotumors recurred: 1 was surgically treated, 1 was treated with selective arterial embolization, and 1 clinically followed. At the final follow-up, Cr and Co blood ions beyond the threshold decreased from 85.7% cases to 0% in the seven patients that could be evaluated. Conclusions: The one-stage strategy of radical excision and revision with non-MOM couplings in pseudotumors due to MOM hip arthroplasty achieved good 3-year outcomes. However, complications were frequent (23%). Recurrences were not rare (14%) and did not require implant re-revision.

Arthroscopic tendon release for iliopsoas impingement after primary total hip arthroplasty: a retrospective, consecutive series.

INTRODUCTION: Aim of this study was to describe the clinical outcomes of 16 patients with iliopsoas (IP) impingement after primary total hip arthroplasty (THA), treated with an arthroscopic tendon release. METHODS: 16 patients (11 females/5 males), with a mean age of 57.8 ± 11.1 years (age at THA: 54.4 ± 11 years) and a diagnosis of IP impingement after primary THA, were treated with the Wettstein tenotomy. Preoperatively, every patient underwent a diagnostic ultrasonography guided peritendinous injection and a computed tomography (CT) scan. Every patient was clinically evaluated using WOMAC score. Subjective pain relief and active hip flexion strength were measured. RESULTS: No complications related to arthroscopy were detected. Every cup was prominent with a mean axial overhang of 13 ± 4.8 mm (range 5-20 mm). At a mean follow-up of 27 ± 20.1 months (range 6-48 months), the WOMAC score was 83.7 ± 10.1 points. 13 patients out of 16 (81.3%) had a complete pain relief. 14 patients out of 16 (88%) regained full active hip flexion strength at the final follow-up. 1 patient was scheduled for cup revision after 6 months, due to persistent symptomatology. No demographic data or CT measurements about cup position statistically influenced the outcome. CONCLUSIONS: When preceded by an appropriate diagnosis, arthroscopic tenotomy proved safe and effective for IP impingement, regardless the magnitude of cup protrusion.

Revisions for Periprosthetic Hip Infections Do Not Fail More Than Revisions for Aseptic Loosening, but Mortality is Higher.

BACKGROUND: The influence of the reasons for revision on the outcomes of revision hip arthroplasties is controversial and poorly described. A registry study was designed to compare the revision hips performed for periprosthetic hip infection (PHI) to the revision hips performed for aseptic loosening. The aims of this study were the long-term assessment and comparison of survival rates, reasons for rerevisions, and mortality rates between these two cohorts. METHODS: By using an arthroplasty registry, revision hips were stratified according to the reasons for revision (aseptic loosening and PHI). Preoperative and intraoperative, demographic and implant-related features were recorded. Survival rates, reasons for revision and mortality rates were assessed and compared. RESULTS: The two cohorts were homogenous for preoperative and intraoperative parameters, apart from age at revision, time elapsed between THA and revision, bearing surfaces, and head size. At 10 years, the survival rates were similar between the two groups (P = .51). Half of the rerevisions occurred in the first two years in both the groups. The reasons for rerevision were similar: when rerevision for infection was adopted as an end point, the two cohorts showed nonsignificant differences. The mortality rate was statistically higher in the PHI cohort (P .0015, hazard ratio adjusted for age and gender: 1.42). CONCLUSION: Aseptic and septic revisions achieved similar outcomes at long-terms, rerevisions tended to fail for the same reason for revision. The mortality rate was significantly higher in the septic cohort. These findings are useful to modify and tune the preoperative, intraoperative, and postoperative managements of revisions.

Metal on metal hip arthroplasty surveillance at a tertiary centre: design, patients' adherence, and cost analysis.

PURPOSE: Metal-on-metal (MOM) bearings may carry higher than expected revision rates and serious complications: an appropriate surveillance may be advocated. Aims of this paper were to (1) present the biennial experience of MOM surveillance in a tertiary centre, (2) describe the patients' adherence to monitoring, and (3) analyze the costs of the surveillance METHODS: The design of MOM surveillance was developed according to the guidelines of the Italian Society of Orthopaedics and Traumatology. The adherence to every follow-up was expressed as raw numbers and percentages. A cost analysis (direct and indirect costs) was conducted and projected in a five year time span. RESULTS: About 61.1% of patients adhered to the first step of the surveillance, and 13.5% answered to a specific questionnaire about MOM implant. About 36.2% of the patients participated for the annual follow-up, and 18.1% entered the six month follow-up program. Of the implants, 2.5% required a revision. A two year surveillance costs €45,520.30, €236,443.98 (57.7%) including revisions. Five-year projected costs will be €23.113,64 (5.6%). Hospital indirect costs, including personnel working days, were €150,392.30 (36.7%). The estimated economic burden for seven years will be €409,949.92 (direct € 259,557.62, indirect €150,392.30). CONCLUSION: Patients' adherence to MOM surveillance is modest and the rate of dropouts seems not to stop over the time. Most of the expenses are due to revision surgeries, as well as indirect costs. Economy of scale may be suggested to reduce the costs, involving as much MOM population as possible.

Mid-term outcomes of a partial 2-stage approach in late chronic periprosthetic hip infections.

INTRODUCTION: Late chronic periprosthetic infections (LCPIs) are worrisome complications of primary hip arthroplasties. The gold standard procedure is the 2-stage revision. 1-stage exchange is gaining popularity in order to reduce the invasivity of the former technique. A partial 2-stage exchange technique, retaining fixed components, may overcome some of the drawbacks of the previous techniques, allowing a much easier reconstruction step. METHODS: 28 patients with a LCPI after a primary total hip arthroplasty underwent a first removal stage: the loosened component was removed (23 cups and 5 stems) and the fixed component, with no local signs of infection, was retained. An antibiotic hand molded spacer was positioned in 16 cases. After a mean time of 8 months and a tailored antimicrobial therapy, the spacer was removed and the implant was revised. RESULTS: The mean follow-up was 5 years. The HHS score was 82.7. 4 cases failed (2 patients presenting a septic relapse after revision and 2 patients undergoing Girdlestone arthroplasty), achieving a survival rate of 83.4% at 5 years. 2 patients were unwilling to perform a further procedure and did not proceed to the second stage. All the other patients had no clinical, radiological, laboratory signs of septic relapse. CONCLUSIONS: The partial 2-stage approach seems a promising technique for LCPI in selected cases, with good infection control. It allows an easier revision by sparing the fixed components. Larger case series and longer follow-ups are needed to confirm the results and identify the limits of this approach.

Cementless Total Hip Arthroplasty in Crowe III and IV Dysplasia: High Hip Center and Modular Necks.

BACKGROUND: Total hip arthroplasty (THA) in severe developmental dysplasia of the hip (DDH) is a challenging procedure. The most used techniques involve anatomic cup positioning, augmentation femoral osteotomy. However, anatomic cup positioning is not always feasible in severe DDH and osteotomy nonunion may ensue. The purpose of the study was to assess the survivorship, the hip score results, the radiological parameters (fixation, loosening, component position) of a large cohort of patients with Crowe III and IV DDH, treated with high hip center and modular necks THAs. METHODS: Eighty-four THAs in Crowe III and IV DDH were evaluated, achieving a final follow-up of 15.1 years. All the patients were treated with the same cementless implant (modular necks and ceramic-on-ceramic coupling) and the same approach (high cup placement with slight medialization). The patients were clinically evaluated (Harris Hip score and Merle d'Aubigne and Postel score). A radiographic evaluation was performed, analyzing the orientation of the cup. RESULTS: Eighty patients were available at the last follow-up. The clinical scores were good at the final follow-up. Two sciatic lesions occurred: one patient fully recovered. The overall survivorship was 90.5% at 15 years: only 2 cases of aseptic loosening were reported. The mean center of rotation height was 33 ± 8 mm and the medialization was 30 ± 5 mm. CONCLUSION: A high cup placement with slight medialization is a valid technique in DDH patients. A good restoration of the offset, ceramic-on-ceramic coupling and a porous socket may provide durable results, overcoming the effects of increasing joint reaction forces related to high cup placement.

Short Stems Versus Conventional Stems in Cementless Total Hip Arthroplasty: A Long-Term Registry Study.

BACKGROUND: Short stems in total hip arthroplasty (THA) have recently gained increasing popularity, allowing mini-invasive exposures and bone-sparing approaches. However, long-term studies and recommendations for the routine use are not available. The aim of this report was to compare the survival rates and the reasons for revision of short stems versus conventional stems in cementless THAs, in a registry-based population. METHODS: The Registry of Prosthetic Orthopedic Implants (RIPO) was inquired about cementless THAs performed since 2000 to 2016. The stems were divided into short (<12 cm) and conventional ones, and then, classified according to the classification by Feyen and Shimmin: short stems with neck-retaining osteotomy (group A: 1684 hips), short stems with standard osteotomy (group B: 2727 THAs), and conventional stems (group C: 57,359 cases). Demographics, survivorships, and reasons for revision were investigated and compared. RESULTS: Short stems were preferentially implanted in younger patients and normal morphologies. Short and conventional stems showed comparable survival rates at long-term follow-up (>90% at 15 years). The rates of stem aseptic loosening, intraoperative fractures, and periprosthetic fractures were similar in the 3 groups. Group B had higher rates of revisions due to primary instability (early dislocations and impingement-related events; P < .05). Revisions due to pain were nonsignificantly higher in group B. CONCLUSION: Short stems are reliable implants at long-term follow-up. The comparison with conventional stems showed no additional risk of premature aseptic loosening and intraoperative and periprosthetic fractures. However, the high rate of revisions due to pain and, mostly, primary instability should be investigated in clinical trials.

Double-Incision Approach and Early Rehabilitation in a Complicated Bicondylar Tibial Plateau Fracture: A Case Report.

OBJECTIVE: The main goal of this case was to report the treatment of bicondylar fractures of the tibial plateau and the restoration of the metaphyseo-diaphyseal dissociation. CLINICAL PRESENTATION AND INTERVENTION: A 54-year-old male who was cycling had a road accident that caused a closed fracture of the right tibial plateau and proximal fibula diagnosed by X-rays. The patient underwent surgery and was immobilized with a long-leg splint for 4 weeks. After immobilization, aggressive rehabilitation was done. Progressive quadriceps strengthening, movements to improve symmetrical weight bearing, and functional activities were performed. The patient improved muscle strength and obtained high scores for gait and balance in a relatively short time. CONCLUSION: In this report, a bicondylar tibial fracture treated with a two-incision approach and a double-plate osteosynthesis provided strong fracture stabilization and thereby allowed an early mobilization with aggressive rehabilitation.

3rd generation alumina-on-alumina in modular hip prosthesis: 13 to 18 years follow-up results.

INTRODUCTION: Ceramic-on-ceramic (CoC) couplings are alternative bearings surfaces that have been reported to reduce osteolysis, wear debris and aseptic loosening compared to the use of polyethylene. Early experiences with ceramics had poor results, but they have led to many improvements in the manufacture and design of subsequent implants. METHODS: We analysed medical files of 300 CoC total hip arthroplasty (THA) with a modular neck performed during period 1995-2000 by a single surgeon for a minimum follow-up of 13 years, evaluating clinical and radiological outcome. RESULTS: The mean clinical Merle d'Aubigne and Postel hip score at the final follow-up is 17.4, against a preoperative value of 11.4. Overall survivorship with an endpoint of revision is 93.2% (95% CI, 89.0%-97.3%) at 15 years, while considering only prosthesis failures related to aseptic loosening and ceramic breakage, survival rate at 15 years is 97.2% (95% CI, 94.8%-100%). We observed complications that led to revision surgery in 11 patients (4%) (periprosthetic fractures, liner ruptures, septic loosening of the implant, aseptic loosening of the cup, aseptic loosening of the stem). The occurrence of squeaking is low (1.6%, 4 cases) and we analysed the characteristics of these patients. DISCUSSION: Our study shows an excellent long term survivorship of third generation alumina CoC THA. We reiterate the importance to have a stable implant to maximise the advantage of ceramic and to avoid complications.

Periprosthetic femoral fractures: treatments and outcomes. An analysis of 47 cases.

We evaluated the treatment and outcome of 47 cases of periprosthetic femoral fracture presenting to our unit over a nine-year period. The average follow-up period was 48 months (range 24-114). Surgical treatment involved stem revision in 29 hips, open reduction and internal fixation in 11 hips and conservative treatment in seven hips. The mean HHS at the most recent follow-up was 74 (range 49-91). Twenty-five patients were pain-free (53%), 10 patients had occasional mild pain (21%), eight patients had a limp and pain (17%) and four patients had severe disability (9%). Postoperative radiographs showed complete fracture union in all 47 patients. There were 11 complications: three further periprosthetic fractures, two aseptic loosenings, two dislocations, two aseptic loosenings of the primary prostheses, one stem breakeage, and one intraoperative fracture. Our results suggest cementless revision with tapered fluted stems used without cortical strut grafts are a valid procedure for the treatment of Vancouver B2 and B3 periprosthetic fractures.

Coronary plaque quantification and composition in asymptomatic patients with type II diabetes mellitus.

OBJECTIVE: The aim of this study was to characterize the extent and morphology of coronary lesions in asymptomatic patients with type II diabetes mellitus. METHODS: We enrolled 102 asymptomatic patients with type II diabetes mellitus and 97 patients without diabetes as controls. All individuals had no history of ischemic heart disease. They underwent multidetector computed tomography (MDCT). Plaque density and plaque volume were calculated using specific software on axial images. Arterial remodeling was evaluated with semiquantitative assessment on image reconstructions. RESULTS: MDCT angiography revealed the presence of 124 coronary plaques in 46 patients with type II diabetes mellitus and 59 plaques in 21 controls (P<0.01). Diabetic patients had a significantly higher proportion of lesions with impaired adaptive remodeling (56.5 versus 35.6%, P<0.01), as compared with nondiabetic individuals. The volume of fibrofatty component was 0.1 cm (0.01-0.72) in diabetic patients and 0.08 cm (0.01-0.33) in controls (P=0.14). The calcium volume was 0.082 cm (0-0.558) in diabetic patients and 0.12 cm (0-0.669) in controls (P=0.21). Plaques with fibrofatty components had a significantly higher density in the diabetic cohort (58.76  ±  9.55  Hounsfield Units), as compared with the control group (47.31  ±  5.42 Hounsfield Units, P<0.001). Plaque density correlated with the duration of type II diabetes mellitus (r=0.37, P=0.044), but was independent of age, sex, hypertension and metabolic profile. In the control group, plaque density was independent of any covariate. CONCLUSION: Coronary plaques in type II diabetes mellitus show a tendency to develop impaired adaptive remodeling and to have a higher tissue density.

Solitary eosinophilic granuloma of the adult lumbar spine.

INTRODUCTION: Eosinophilic granuloma (EG) is a benign bone tumor that rarely occurs in adults. It is usually found occurring in flat and long bones, but spine is often affected too. EG is of unknown aetiology, and the course of the disease is unpredictable. MATERIALS AND METHODS: Two cases of EG of the adult lumbar spine are reported, representing a difficult challenge for diagnosis and treatment. CONCLUSION: CT scan guided trocar biopsy allowed to achieve a definitive diagnosis, and CT scan guided intralesional infiltrations of corticosteroids were the successful treatment.

Gorham-Stout disease: the experience of the Rizzoli Institute and review of the literature.

Gorham-Stout disease (also known as "disappearing bone disease") was first described by Jackson in 1838, but was properly defined by Gorham and Stout in a series of 24 patients in 1954-1955. It is a rare disease of unknown etiology (about 200 cases reported in the literature) characterized by spontaneous progressive resorption of bone without malignant proliferation of vascular structures. The diagnosis is one of exclusion and it is based on combined histological, radiological, and clinical features. Benign vascular proliferation with fatty bone marrow and thinning of bony trabeculae is a typical histological feature. Standard radiographs of disappearing bone disease show progressive bony resorption with adjacent soft tissue involvement. Most cases of Gorham-Stout disease resolve spontaneously, but prognosis remains unpredictable. This study reports 13 cases of Gorham-Stout disease treated in our institution from 1968 to 2008. The aim of the work was to review our series and the literature on this rare disease, as well as to evaluate whether or not an optimal treatment can be identified and recommended.

Clinically significant thromboembolic disease in orthopedic oncology: an analysis of 986 patients treated with low-molecular-weight heparin.

BACKGROUND AND OBJECTIVES: Thromboembolic risk in orthopedic oncology is high due to several factors. The aim of this study was to assess clinically significant thromboembolic disease in 986 patients operated on with a prosthetic reconstruction of the lower limbs after the resection of bone tumors and prophylactically treated with low-molecular-weight heparin (LMWH). METHODS: Between 1983 and 2006, 986 patients had uncemented megaprostheses after a resection of the lower limbs for bone tumors. Antithromboembolic prophylaxis was always administered with LMWH from the immediate postoperative time until the time of complete weight-bearing. Phlebographies and vascular ecodoppler were not performed postoperatively on a regular basis. Patients were followed in the clinic with imaging studies for several years (lower limb CT, MRI, CT of the chest for malignant tumors). The diagnosis of symptomatic venous thromboembolism (VTE) was established or excluded on clinical evidence and MRI study. RESULTS: Among the 986 cases treated, only 11 patients (1.1%) showed a major thromboembolic event confirmed clinically and through imaging. One of these patients died with pulmonary embolism a few days after surgery. Two cases of thromboembolism occurred in patients with a vascular bypass. CONCLUSIONS: Despite general oncologic and orthopedic factors favoring VTE, the clinical occurrence of this event was extremely low in this series, probably due to a consistent and careful prophylaxis, prolonged until the time of complete weight-bearing.

The role of surgery and adjuvants to survival in Pagetic osteosarcoma.

BACKGROUND: Osteosarcoma is a rare complication of Paget's disease with a very poor prognosis. Treatment is controversial: the older age of the patients affected by Paget's disease may limit the use of chemotherapy and axial involvement may limit the practicality of surgery. QUESTIONS/PURPOSES: The purposes of this study are (1) to report the survival in patients treated for osteosarcoma in Paget's disease; (2) to identify correlations between type of treatment and survival comparing our data with those in the literature; (3) to determine if the extent of Paget's disease and risk of malignant transformation are associated; (4) to assess if prognosis is related with site; and (5) to identify the variations of histologic subtypes of these osteosarcomas. METHODS: We retrospectively reviewed the medical records of 26 patients treated between 1961 and 2006 who had bone sarcoma arising from a site of Paget's disease. Twenty two of the 26 patients had surgery. In six surgery only was performed; three had surgery, adjuvant chemotherapy, and radiotherapy; one surgery and radiotherapy; 12 underwent surgery and chemotherapy, adjuvant in 10 patients and neoadjuvant in two; two had only radiotherapy and two had only chemotherapy. We performed survival analyses between various combinations of treatment. RESULTS: At last followup four patients had no evidence of disease (NED) at a minimum followup of 42.6 months (mean, 139 months; range, 42.6-257.4 months) and 22 died with disease (DWD) at a minimum time of 1 month (mean, 20.2 months; range, 1-84 months). One of the six patients (11%) treated with surgery only had NED at 10 years; the other five died from disease at a mean of 30 months. Three of 12 patients (25%) treated with surgery and chemotherapy are NED at a mean followup of 12 years; nine died of disease at a mean of 24 months. All patients treated without surgery died at a mean of 7.5 months (range, 1-13.7 months). CONCLUSIONS: Despite improvements in surgery and medical treatments the prognosis remains poor in patients with Paget's sarcoma.

Surgical margins and local control in resection of sacral chordomas.

BACKGROUND: The treatment of choice in sacral chordoma is surgical resection, although the risk of local recurrence and metastasis remains high. The quality of surgical margins obtained at initial surgery is the primary factor to improve survival reducing the risk of local recurrence, but proximal sacral resections are associated with substantial perioperative morbidity. QUESTIONS/PURPOSES: We considered survivorship related to local recurrence in terms of surgical margins, level of resection, and previous surgery. METHODS: We retrospectively reviewed 56 patients with sacral chordomas treated with surgical resection. Thirty-seven were resected above S3 by a combined anterior and posterior approach and 19 at or below S3 by a posterior approach. Nine of these had had previous intralesional surgery elsewhere. The minimum followup was 3 years (mean, 9.5 years; range, 3-28 years). RESULTS: Overall survival was 97% at 5 years, 71% at 10 years, and 47% at 15 years. Survivorship to local recurrence was 65% at 5 years and 52% at 10 years. Thirty percent of patients developed metastases. Wide margins were associated with increased survivorship to local recurrence. We found no differences in local recurrence between wide and wide-contaminated margins (that is, if the tumor or its pseudocapsule was exposed intraoperatively, but further tissue was removed to achieve wide margins). Previous intralesional surgery was associated with an increased local recurrence rate. We observed no differences in the recurrence rate in resections above S3 or at and below S3. CONCLUSIONS: Surgical margins affect the risk of local recurrence. Previous intralesional surgery was associated with a higher rate of local recurrence. Intraoperative contamination did not affect the risk of local recurrence when wide margins were subsequently attained.

Unusual radiographic appearance of adamantinoma.

Adamantinoma is a rare tumor with an indolent course that occurs most commonly in the tibia. It is locally aggressive, and local recurrences are described after resection. Pain is the most common symptom. Since the lesion is typically slow growing, the pain can be present for many years before the patient seeks medical attention. Microscopically, adamantinoma consists of islands of epithelial cells in a fibrous stroma. Nuclear atypia is minimal, and mitotic figures are rare. The most common radiographic appearance is that of multiple sharply demarcated radiolucent lesions surrounded by areas of dense, sclerotic bone. This tumor most often affects the tibial diaphysis and produces lytic lesions that can cause fractures. A 31-year-old man presented with a rapidly growing lytic lesion of the distal tibia. On histological examination, many areas of epithelial cells in a fibrous stroma were identified. Diagnosis of adamantinoma was performed. The lesion was treated with en bloc resection and reconstruction with distal tibia allograft and ankle arthrodesis with retrograde nail. At 2-year follow-up, there were no clinical or radiological signs of recurrence of disease.

Secondary aneurysmal bone cyst in fibrous dysplasia of the proximal femur.

Fibrous dysplasia of bone is a congenital skeletal disorder characterized by proliferation of spindle cells inside an intramedullary collagenous stroma and by formation of metaplastic bone. An aneurysmal bone cyst is a lesion of unknown etiology. Macroscopically it appears like a blood-filled cavity that expands the affected bone. Histologically, fibrous septa are bordered by macrophages, giant cells, inflammatory cells, and areas of bone production. Hemorrhagic areas can rise into fibrous dysplasia. The lesion appears as an aggressive and destructive process that is difficult to diagnose properly. A 29-year-old woman presented with a 2-year history of left inguinal and lumbar pain. She reported increased pain after physical activity. Magnetic resonance imaging of the left femur (without intravenous gadolinium) showed a mass extending 14 cm along the femoral metaphysis. This lesion involved cortical bone that was broken in the posteromedial site. Computed tomography confirmed the osteostructural lytic alteration that "blows up" the proximal femur metaphysis. A trochar biopsy allowed the diagnosis of aneurysmal bone cyst on fibrous dysplasia, excluding malignancy. The lesion was treated with curettage and local adjuvants and filled with bone grafts. Internal fixation with a sliding screw plate was also performed. Radiographs at 1 year postoperatively showed good consolidation of the grafts and absence of local recurrence. The patient achieved active and passive mobilization of the left hip with no pain.