[Arthroplasty registers as post-marketing surveillance systems: the Catalan Arthroplasty Register]. / Los registros de artroplastias como sistemas de vigilancia poscomercialización: el Registro de Artroplastias de Cataluña.

OBJECTIVE: The aim is to present the functioning and results of the Catalan Arthroplasty Registry (RACat). MATERIAL AND METHOD: The RACat arose by the initiative of the Catalan Society of Orthopaedic Surgery and Traumatology, the Catalan Health Service (CHS) and the Catalan Agency for Health Information Assessment and Quality. Publicly funded hospitals sent information through the Internet (CHS Applications website) on knee and hip arthroplasties: patient identification, hospital, joint (hip/knee), type (primary/revision), side of operation, date of surgery and prosthesis (manufacturer's name and reference number). The quality of the data is analysed regularly. We estimate the risk of replacement by the Kaplan-Meier method. RESULTS: A total of 52 hospitals out of 62 send data to RACat, and information on 36,951 knee and 26,477 hip arthroplasties is available. Data quality improved between 2005 and 2010. In 2010 coverage exceeded 70%, with side of operation 97%, and prostheses identification of 80%. The risk of replacement at three years was 3.3% (95% CI:3.1-3.6) for knee, 2.9% (95% CI:2.5-3.3) for total hip, and 2.5% (95% CI:2.0-3.1) for partial hip. DISCUSSION: Risk of replacement is higher than that observed in other registers, although data quality and its improvement over time should be taken into account. CONCLUSIONS: The information available in the RACat will help to establish a standard that will enable hospitals to compare results.

[Calcific myonecrosis of the leg]. / Mionecrosis calcificante de la pierna.

Calcific myonecrosis is a rare post-traumatic sequela almost exclusively located in the lower extremity, which can be mistaken for an aggressive primary neoplasm. This lesion, initially described by Gallei and Thompson in 1960, is characterized by the formation of a calcified mass that appears decades after trauma. The pathophysiologic mechanism is not fully understood, although the lesion most likely results from post-traumatic ischemia and it may be associated with a common peroneal nerve injury. The typical radiographic image is a fusiform soft tissue mass with linear calcifications. The treatment of choice is conservative in asymptomatic patients because the surgical treatment has a high complication rate. We report four cases of calcific myonecrosis treated surgically in our hospital. Three of the cases had an infection as a complication that required subsequent debridement and special therapies to achieve the resolution of the cases.

[What do orthopedic surgeons need to know from radiologists?]. / ¿Qué necesitan saber los cirujanos ortopédicos del radiólogo?

The diagnosis of tumors and pseudotumors depends on three pillars: the clinician, the radiologist, and the pathologist. The first two can establish a presumptive diagnosis on the basis of the clinical presentation and findings on complementary tests, whereas the pathologist will have to reach the definitive diagnosis after analyzing the biopsy specimens. Obviously, the clinician and radiologist should reach a consensus regarding the diagnostic orientation; however, for this to happen there must be a relationship between the two professionals and they must work together for the benefit of the patient. Orthopedic surgeons, like any other group of specialists, would like to have radiologists working in their own center who are dedicated to the organ/system they treat, in this case the locomotor apparatus, and who can provide them with their opinion about the different images obtained. This point is very important and especially so for tumors, because this type of disease is uncommon and few specialists are dedicated to it. For this reason, when faced with a lesion that has the characteristics of a tumor, orthopedic surgeons would like radiologists to give the most accurate description of the images as possible, defining the characteristics of benignity or malignancy of the process as well as indicating the risk of fracture in a metastatic lesion. On the other hand, orthopedic surgeons would ask for a clear and comprehensible description of the images obtained in complementary tests, because orthopedic surgeons have less experience in this type of images and they are often difficult to interpret. Another aspect that is often mentioned in discussions among orthopedic surgeons is the importance of having a radiology department that performs interventional procedures. Radiologists that perform interventional procedures can facilitate our work very much, both in the diagnosis and in the treatment of certain bone tumors. Finally, we would like to stress the importance of having a radiologist who collaborates with us and is interested in our work, supporting us without being overly critical. This is also important for our relations with patients; radiologists, like all professionals, must know their responsibilities and limitations in aspects related to intervention and in elaborating the corresponding reports.

Complication of an insufficiency fracture of the acetabulum.

An 83-year-old woman presented to the emergency department with a history of pain in the left hip of gradual onset over several days. There was no history of trauma and the X rays showed degenerative changes in the hip joint but no apparent fracture. She was sent home after being given reassurance, analgesics and a cane. Three weeks later she returned unable to mobilise after falling while getting out of bed and injuring the left hip. On this occasion the X-rays showed an acetabular fracture with femoral head protrusio. A CT scan confirmed the diagnosis and also demonstrated the absence of a haematoma in the surrounding soft tissues. The latter is characteristic of insufficiency fractures. Orthopaedic surgeons require a high index of suspicion for insufficiency fractures of the pelvis, femoral head and femoral neck in elderly osteoporotic patients who complain of hip pain without any history of trauma.

Subperiosteal leiomyosarcoma of the tibia.

Primary leiomyosarcoma of bone is a rare malignant tumor of smooth muscle. We report a case of low-grade subperiosteal primary bone leiomyosarcoma in the tibial diaphysis, which radiologically appeared to be osteoid osteoma. A 35-year-old man presented with a several-year history of a palpable hard nodule in the distal left leg, which had enlarged and become painful over the previous 2 years. Radiographs showed solid periosteal reaction with a well-defined lytic lesion in the posteromedial cortical border of the left tibial diaphysis. Computed tomography demonstrated a small, well-defined lytic lesion, not calcified, in a subperiosteal location, surrounded by solid periosteal bone formation. The lesion was excised en bloc and the histological diagnosis of a low-grade leiomyosarcoma was made. To the best of our knowledge, the surface location of primary bone leiomyosarcoma has not been previously described in the literature.

MR imaging of synovial tumors and tumor-like lesions.

The clinical diagnosis of synovial tumors and tumorlike lesions is difficult, and radiographic findings may establish a confident diagnosis only in some cases. MR imaging has become the modality of choice in evaluating these lesions, because with it a presumptive diagnosis can be made in most cases. Our goal is to review the MR features of pigmented villonodular synovitis, giant-cell tumor of the tendon sheath, synovial chondromatosis, synovial hemangioma, lipoma arborescens, synovial cysts and synovial sarcoma, emphasizing those findings that suggest a specific diagnosis.

Comparative multiple-dose study of ketorolac tromethamine and diflunisal for pain following orthopaedic surgery.

A total of 100 patients were enrolled after orthopaedic surgery in a multiple-dose, randomized, double-blind, parallel-group study to compare the analgesic efficacy and safety of 10 mg ketorolac tromethamine given orally four times daily for 3 days with 500 mg diflunisal given orally twice daily plus placebo twice daily for 3 days. Ketorolac was significantly (P = 0.04) superior to diflunisal in reducing the pain severity during the first 9 h of treatment; a difference possibly related to the more flexible dosage regimen of ketorolac. Patients and the investigator, however, rated ketorolac and diflunisal as being equally effective in terms of the overall drop in severity of pain and pain relief at the end of days 1, 2 and 3. Ketorolac-treated patients reported a total of nine adverse events and diflunisal-treated patients reported 13. It is concluded that in the treatment of acute post-operative pain a drug with a more flexible dosage regimen may provide superior pain relief.