Does a titanium sleeve reduce the frequency of pseudotumors in metal-on-metal total hip arthroplasty at 5-7years follow-up?

INTRODUCTION: Little is known about pseudotumor frequency and risk factors for pseudotumor formation among different types of metal-on-metal (MoM) hip arthroplasties. A lower release of chromium and cobalt have been reported in MoM hip arthroplasties with a titanium sleeve compared to MoM designs without a titanium sleeve, but yet it is unknown whether a titanium sleeve reduces the pseudotumor frequency. We conducted a cross-sectional study to investigate: 1) pseudotumor frequency, 2) risk factors of pseudotumor formation 3) and correlations between pseudotumors, serum metal-ions, implant position, and clinical symptoms. HYPOTHESIS: We expected a lower pseudotumor frequency in MoM hip articulation with a titanium sleeve than reported in MoM hip articulation designs using chromium-cobalt sleeve. MATERIALS AND METHOD: A consecutive series of 41 patients/49 hips (31 males), mean age 52 (28-68) years, participated in a 5.5±0.5 (4-6.5) year follow-up study of their M2a_Magnum hip articulation (Biomet Inc., Warsaw, Indiana, USA). Patients were evaluated with magnetic resonance imaging (MRI), measurements of serum metal-ions, plain radiographs, and clinical outcome measures of Harris Hip Score (HHS) and Oxford Hip Score (OHS). RESULTS: Eighteen of 47 hips (38%) had MRI-verified pseudotumors, all cystic, with a mean dimension of 10.6×25.6×41mm. Digital measurements on plain radiographs revealed a higher cup anteversion in patients with a pseudotumor of mean 28.4°±5.05° compared to mean 23.5°±6.5° in patients without a pseudotumor (P=0.009). Serum metal-ion concentrations, acetabular cup inclination and measures of HHS and OHS were similar between patients with and without a pseudotumor (P>0.46). CONCLUSION: At 5.5±0.5years after surgery, MRI-verified cystic pseudotumors were frequently observed in M2a_Magnum hip articulations despite the use of titanium sleeves. The pseudotumors were related to high cup anteversion angles but not related to high serum metal-ions or clinical symptoms. LEVEL OF EVIDENCE: IV: cross-sectional study.

Condylar lesions in relation to mandibular growth in untreated and intra-articular corticosteroid-treated experimental temporomandibular joint arthritis.

OBJECTIVES: To evaluate condylar lesions in relation to mandibular growth in experimental temporomandibular joint (TMJ) arthritis and to assess the outcome of treating this condition with repeated intra-articular corticosteroid injections (IACIs). METHODS: Forty-two 10-week-old rabbits were randomly divided into four groups. Seven animals served as controls. Experimental TMJ arthritis was induced in five animals which received intra-articular TMJ saline injections. Fifteen animals had TMJ arthritis induced and were left untreated and 15 animals had TMJ arthritis induced and were treated with IACIs one week after each TMJ antigen-challenge procedure. Inter-group growth differences were evaluated from head computerised tomography scans taken at the time of arthritis induction and 12 weeks later. The variables assessed were: progression of condylar lesions (erosions/flattening/osteophytes), mandibular bone volume changes, condylar and sagittal ramus growth. RESULTS: No inter-group differences in the progression of condylar lesions were observed despite reduced mandibular growth in all three experimental groups. The most pronounced unfavourable mandibular growth alterations were observed in the corticosteroid-treated arthritis animals. CONCLUSIONS: No evidence was found in support of a relation between reduced mandibular growth and condylar lesions. We propose that: 1) condylar lesions are not the only causative factor of reduced mandibular growth in experimental TMJ arthritis, and 2) repeated IACIs have a very unfavourable impact on mandibular growth in experimental TMJ arthritis - treatment is more detrimental to mandibular growth than the TMJ arthritis itself.

Ultrasound versus magnetic resonance arthrography in acetabular labral tear diagnostics: a prospective comparison in 20 dysplastic hips.

BACKGROUND: Acetabular labral tears are highly associated with hip dysplasia. Magnetic resonance arthrography (MR arthrography) is the expensive and time-consuming contemporary gold-standard method in the radiological assessment of acetabular labral tears. PURPOSE: To assess the diagnostic ability of noninvasive ultrasound (US) examination compared to MR arthrography in diagnosing acetabular labral tears in dysplastic hip joints. MATERIAL AND METHODS: The study compared US examination and MR arthrography diagnosis of labral tears in 20 consecutively referred dysplastic hip joints. RESULTS: The ability to diagnose acetabular labral tears upon US examination was calculated: sensitivity 44%, specificity 75%, positive predictive value 88%, and negative predictive value 25%. CONCLUSION: The ability of US examination in diagnosing acetabular labral tears is not yet good enough. The technique is still to be developed, and more experience, especially with the interpretation of US examinations, is needed.

Cartilage thickness in the hip joint measured by MRI and stereology--a methodological study.

OBJECTIVE: The purpose of this study was to develop a precise and efficient method for estimating the thickness of the articular cartilage in the hip joint and hence three different stereologic methods were tested based on Magnetic Resonance Imaging. DESIGN: Twenty two females and four males with hip dysplasia underwent MRI. The thickness of the femoral and acetabular cartilage was estimated. RESULTS: The results for all three methods showed that the observed total variance on cartilage thickness is small. The mean thickness of the acetabular cartilage measured by the three different methods ranged between 1.15 mm and 1.46 mm. The mean thickness for the femoral cartilage measured by the three different methods ranged between 1.18 mm and 1.78 mm. The measurements took 15-20 min per hip to carry out. CONCLUSION: Methods 1 and 3 are as precise but we favour method 3 because the measurements are done on images obtained through the center of the femoral head which means that the cartilage surface is intersected perpendicular and partial volume effect avoided. We suggest that this method can be advantageous for assessing the progression of osteoarthritis in dysplastic hips after periacetabular osteotomy.

Retropharyngeal tendinitis: radiographic and magnetic resonance imaging findings.

PURPOSE: To describe the magnetic resonance imaging (MRI) findings in retropharyngeal tendinitis. MATERIAL AND METHODS: Within 1 year, four patients presenting with symptoms of retropharyngeal tendinitis were examined by radiography and MRI. RESULTS: On MRI and radiographs, all patients had characteristic soft-tissue swellings and calcifications related to the tendon of the longus colli muscle situated inferior to the anterior arc of C1. MRI showed well-defined edema, with high signal in the retropharyngeal tissue anterior to C1-C5 on short T1 inversion recovery (STIR) sequences, low signal on T1-weighted sequences, and low signal in the calcification on both sequences. In addition, three patients had high signal intensity changes on STIR sequences in the atlantoaxial joint situated posterior to the anterior arc of C1. CONCLUSION: MRI is a sensitive and accurate method in the diagnosis of retropharyngeal tendinitis. A new finding in this condition is an effusion or synovitis in the anterior atlantoaxial joint. MRI is a valuable tool in differentiating retropharyngeal tendinitis from other diagnoses such as retropharyngeal abscess, pyogenic spondylitis, and spondyloarthropathy.

Contrast-enhanced MRI compared to histological findings in the temporomandibular joint of antigen-induced arthritis in young rabbits.

OBJECTIVE: To study the correlation between histological findings and Magnetic Resonance Imaging (MRI) findings in experimentally induced arthritis in the temporomandibular joint (TMJ) of growing rabbits and to study the effect of intraarticular corticosteroid injections. METHODS: Arthritis was induced by ovalbumin in the left TMJ of 44 pre-sensibilized rabbits. Nine animals died during this procedure. Eight of the remaining animals with induced arthritis were treated with intraarticular corticosteroid injections one week after induction of arthritis. Twelve rabbits served as controls. MRI enhanced with Gadolinium-DTPA was performed on all animals 1 to 2 weeks after induction of arthritis and again before sacrifice and the degree of enhancement was calculated. Histology of the condyle was performed and degree of villous hyperplasia, synovial thickness, infiltration of inflammatory cells and pannus was graded. RESULTS: TMJ arthritis was successfully induced in the rabbits and was verified by enhancement of the MRI and by histological changes one week after the induction. Joints treated with intraarticular corticosteroid injections revealed complete inhibition of the inflammation. CONCLUSION: Enhancement of MRI in antigen-induced arthritis in the TMJ associated well with inflammatory changes shown histologically. An intraarticular corticosteroid injection prevents the initial inflammatory response in experimentally induced TMJ arthritis.

Posterolateral spinal fusion at unintended levels due to bone-graft migration: no effect on clinical outcome in 19/130 patients.

In a prospective randomized study, we evaluated the risk of lumbar posterolateral spinal fusion at an unintended level due to bone graft migration. 130 patients underwent fusion supplemented by pedicle screw fixation (Cotrell-Dubousset, 64 patients) or uninstrumented fusion (66 patients). This was assessed by two independent observers on antero-posterior, and lateral radiographs taken 1 year after surgery. All patients had ben operated on at the preoperatively planned levels. Both observers agreed that fusion had taken place at an unintended level in 19 cases (14%). We found a tendency towards a higher risk of this "complication" when using supplementary pedicle screw fixation. The functional outcome, assessed by the Dallas Pain Questionnaire and the Low Back Pain Rating scale, was similar in patients having fusion at an unintended level and in patients fused only at the intended levels. There was no difference between the two groups concerning reoperation rates, postoperative smoking or social status. We conclude that unintended fusion occurs and tends to be commoner with the use of pedicle screw instrumentation. However, this complication seems not to affect the functional outcome if fusion has taken place at the intended level.

Interobserver and intraobserver agreement of radiograph interpretation with and without pedicle screw implants: the need for a detailed classification system in posterolateral spinal fusion.

STUDY DESIGN: A prospective randomized clinical study in which four observers evaluated radiographs of posterolateral fusion masses. OBJECTIVES: To evaluate the accuracy of radiograph interpretation of the posterolateral spinal fusion mass when using a detailed classification system and to analyze the influence of metallic internal fixation devices on radiologic inaccuracy. SUMMARY OF BACKGROUND DATA: In general, the literature describing the classification criteria used for radiograph interpretation of spinal posterolateral fusion has serious deficiencies. There is a need for a detailed classification system. METHODS: Seventy patients were randomly allocated to receive no instrumentation (n = 36) or Cotrel-Dubousset instrumentation (n = 34) in posterolateral lumbar fusion. All four observers participated in a prestudy discussion and evaluated the radiographs (anteroposterior, lateral) taken at the 1-year follow-up evaluation. The observers scored the radiographs twice (30 days apart). Each level on each side was judged separately. A continuous intertransverse bony bridge involving at minimum one of the two sides indicated a fusion at that level. "Fusion" indicated this quality of fusion at all intended levels. If the fusion was doubtful on both sides of the interspace, the individual case could not be classified as "fused." RESULTS: The mean interobserver agreement was 86% (Kappa 0.53), and the mean intraobserver agreement was 93% (Kappa 0.78). No difference in interobserver and intraobserver agreement was found between patients with and without supplementary pedicle screw fixation. All mean Kappa values were classified as fair or good. The four observers identified a mean fusion rate of 81%. CONCLUSION: It is extremely difficult to interpret radiographic lumbar posterolateral fusion success. Such an assessment needs to be performed by use of a detailed radiographic classification system. The classification system presented here revealed good interobserver and intraobserver agreement, both with and without instrumentation. The classification showed acceptable reliability and may be one way to improve interstudy and intrastudy correlation of radiologic outcomes after posterolateral spinal fusion. Instrumentation did not influence reproducibility but may result in slightly underestimated fusion rates.

Articular cartilage lesions and anterior knee pain.

The present case-control study included as cases 24 athletes with anterior knee pain, and 17 controls, matching the cases according to gender and age. All cases had their most symptomatic knee examined by magnetic resonance imaging (MRI). Among controls one knee was chosen for examination at random. The MRI of the patella showed articular cartilage lesions in 17 out of 24 cases, whereas among the controls 4 out of 17 had articular cartilage lesions. (Odds Ratio 7.9 (95% confidence interval 1.9-33)). However, presence of articular cartilage lesions was not associated with duration of symptoms or intensity of the anterior knee pain. The present study showed a significant positive association between presence of articular cartilage lesions in the patella and presence of anterior knee pain, but further studies are needed to examine the relationship in detail.

Functional and magnetic resonance imaging evaluation after single-tendon rotator cuff reconstruction.

The aim of this study was to investigate tendon integrity after surgical repair of single-tendon rotator cuff lesions. In 31 patients, 31 single-tendon repairs were evaluated. Thirty-one patients were available for clinical assessment and magnetic resonance imaging (MRI) at follow-up. A standard series of MR images was obtained for each. The results of functional assessment were scored according to the system of Constant. According to MRI evaluation, 21 (68%) patients had an intact or thinned rotator cuff and 10 (32%) had recurrence of a full-thickness cuff defect at follow-up. Patients with an intact or thinned rotator cuff had a median Constant score of 75.5 points; patients with a full-thickness cuff defect had a median score of 62 points. There was no correlation between tendon integrity on postoperative MR images and functional outcome. Patients with intact or thinned cuffs did not have significantly better functional results than patients with retorn cuffs. Because of the presence of metal artifacts and the difficulty in distinguishing postoperative scar tissue from partial tears or thinning, MRI is of minor diagnostic value in assessing the shoulder after cuff repair. However, full-thickness tears are readily diagnosed after operation with MRI.

Recombinant bone morphogenetic protein-7 as an intracorporal bone growth stimulator in unstable thoracolumbar burst fractures in humans: preliminary results.

The study presented here is a pilot study in five patients with unstable thoracolumbar spine fractures treated with transpedicular OP-1 transplantation, short segment instrumentation and posterolateral fusion. Recombinant bone morphogenetic protein-7 in combination with a collagen carrier, also referred to as OP-1, has demonstrated ability to induce healing in long-bone segmental defects in dogs, rabbits and monkeys and to induce successful posterolateral spinal fusion in dogs without need for autogenous bone graft. Furthermore OP-1 has been demonstrated to be effective as a bone graft substitute when performing the PLIF maneuver in a sheep model. Five patients with single-level unstable burst fracture and no neurological impairment were treated with intracorporal OP-1 transplantation, posterior fixation (USS) and posterolateral fusion. One patient with osteomalacia and an L2 burst fracture had an additional intracorporal transplantation performed proximal to the instrumented segment, i.e. OP-1 into T 12 and autogenous bone into T 11. Follow-up time was 12-18 months. On serial radiographs, Cobb and kyphotic angles, as well as anterior, middle and posterior column heights, were measured. Serial CT scans were performed to determine the bone mineral density at fracture level. In one case, radiographic and CT evaluation after 3 and 6 months showed severe resorption at the site of transplantation, but after 12 months, new bone had started to fill in at the area of resorption. In all cases there was loss of correction with regard to anterior and middle column height and sagittal balance at the latest follow-up. These preliminary results regarding OP-1 as a bone graft substitute and stimulator of new bone formation have been disappointing, as the OP-1 device in this study was not capable of inducing an early sufficient structural bone support. There are indications to suggest that OP-1 application to a fracture site in humans might result in detrimental enhanced bone resorption as a primary event.

Contrast enhanced magnetic resonance imaging as a method to diagnose early inflammatory changes in the temporomandibular joint in children with juvenile chronic arthritis.

OBJECTIVE: Recent studies have stressed early diagnosis of temporomandibular joint (TMJ) involvement in children with juvenile chronic arthritis (JCA) to initiate treatment before destruction of the condylar head and growth alterations take place. TMJ involvement is often asymptomatic, but studies with contrast enhanced magnetic resonance imaging (MRI) in other joints have shown that it is possible to detect the early inflammatory changes. METHODS: Thirty TMJ in 15 children with newly diagnosed JCA (mean age 12.0 years) were examined clinically, with radiographs and with MRI enhanced with gadolinium diethylene thiamine pentaacetic acid (Gd-DTPA). A control group of 10 healthy children (mean age 11.5 yrs) were examined clinically and with MRI. The MRI variables included T1 weighted images before and after administration of Gd-DTPA with and without fat suppression. RESULTS: MRI enhanced with Gd-DTPA indicated inflammatory activity in 87% of the patients. Conventional MRI without contrast medium proved to be insignificant in diagnosing early inflammatory changes. CONCLUSION: Enhanced MRI is very efficient in diagnosing early inflammatory changes of the TMJ and is a more sensitive method than the clinical examination and radiographs.

Hemifacial spasm: magnetic resonance angiography.

Twenty-three consecutive patients with hemifacial spasm were studied. Magnetic resonance imaging angiography of the brain was performed in 20 patients and 15 controls. The angiograms were evaluated by two independent observers and blinded for side-location of the spasm. Contact between an artery from the vertebrobasilar circulation and the intracranial part of the facial nerve was observed ipsilaterally to the spasm in 17 patients (85%) and in two of 30 control half-brains (7%), respectively. Treatment is discussed. The study confirms that arterial relation to the facial nerve root is the most frequent cause of hemifacial spasm. Magnetic resonance imaging is recommended to exclude mass lesions in the posterior cranial fossa, and magnetic resonance angiography is recommended in preoperative evaluation and in research.

[Hemifacial spasms--clinical picture, diagnosis and treatment]. / Hemifaciale spasmer--klinisk billede, undersøgelse og behandling.

A rectrospective study of 23 consecutive patients with hemifacial spasm is presented. Based on this experience, a practical approach to the diagnosis, investigation and treatment with injections of botulinum toxin is described. Magnetic resonance imaging angiography of the brain was performed in 20 patients an 15 controls. Contact between an artery from the vertebrobasilar circulation and the intracranial part of the facial nerve was observed ipsilaterally to the spasm in 17 patients (85%) and in two controls (7%). Treatment with botulinum toxin was performed in 16 patients with moderate to good improvement in the majority of the patients. MR-angiography is recommended in order to exclude infrequent etiologies and as preoperative evaluation. Botulinum toxin injection is recommended as the symptomatic treatment of choice. The possibility of curative surgical intervention by microvascular decompression of the facial nerve is discussed.

Evaluation of lipomatous soft tissue tumors by MR imaging.

Large soft tissue tumors--5 cm or greater--or deep-seated tumors have a greater risk of being malignant than smaller and superficially located tumors (9). In a period of 2 years 43 consecutive patients with lipomatous tumors 5 cm in diameter or greater were examined with MR imaging. The MR findings were correlated to histologic features and diagnosis. Twenty-six tumors were classic lipomas both on MR and at microscopy; 8 lipomas showed other features--some of them raising suspicion of malignancy at MR; all, however, were histologically benign. Nine tumors were considered malignant at MR imaging; all 9 proved to be malignant by microscopy.

Migration of hydroxyapatite coated femoral prostheses. A Roentgen Stereophotogrammetric study.

We allocated randomly 27 patients undergoing 28 primary uncemented total hip replacements (THR) to receive prosthetic components of similar design with either plasma-sprayed titanium alloy (Ti) coating (n = 13) or hydroxyapatite (HA) coating (n = 15). After some exclusions, 15 of the patients (15 THR; 7 with HA- and 8 with Ti-coating) were followed by roentgen stereophotogrammetric analysis at 3, 6 and 12 months to measure migration of the femoral component. Twenty-six of the patients (26 THR) were followed clinically and by conventional radiography. All the femoral components had migrated at 3 months. From 3 to 12 months, the migration of Ti-coated components continued whereas the HA-coated components had stabilised. At 12 months there was significantly less migration of the HA-coated components (p < 0.05). The maximum subsidence was 0.2 mm in both groups. The Harris hip score was equal in the two groups preoperatively but at follow-up it was better in the HA-coated group (p < 0.05) and visual analogue scale scores showed that they had less pain (p < 0.05).

Influence of cisapride on food-stimulated gastro-oesophageal reflux: a radiological study.

The influence of Cisapride on food-stimulated gastro-oesophageal reflux mechanisms was studied in a double-blind cross-over investigation in 24 consecutive patients selected by endoscopy, 12 with microscopical evidence of gastro-oesophageal reflux and 12 with additional macroscopic oesophagitis. 63% had food-stimulated gastro-oesophageal reflux, and Cisapride significantly reduced the tendency to gastro-oesophageal reflux and mucosal contact time between gastric content and the oesophageal mucosa in 73% of these patients. It is concluded that Cisapride could be valuable in the treatment of gastro-oesophageal reflux.

[Osteochondritis dissecans of the calcaneus]. / Osteochondritis dissecans af calcaneus.

We report a case of osteochondritis dissecans located to the posterior calcanear articular surface of the talocalcaneal joint. The lesion was diagnosed by radiological tomography of the joint. The treatment was surgical excision of the affected segment. The patient was still symptomfree three years later.

Fractures of the spine in ankylosing spondylitis.

Fractures through the disc or the vertebral body as well as the posterior elements are typically seen in ankylosing spondylitis. The fractures can be compared to the fractures of long bones and are often unstable. These fractures are usually associated with increasing pain and may be the result of minor traumas. The radiographic appearance may be discrete, but overlooking the fracture may have disastrous consequences. The characteristic features and the biomechanical pathogenesis of these fractures are reviewed.

The incidence of gastro-oesophageal reflux after solid and semi-solid meal.

The influence of different foodstuffs, solid meal, semi-solid meal and solid bolus, was investigated in 21 patients with food-stimulated gastro-oesophageal reflux. All 21 had GE reflux following solid meal, 9 after semi-solid and 11 after solid bolus. The result could not be explained by difference in fat content or reproducibility. It is concluded that information concerning test meals could be of importance when comparing different GE reflux populations.