Radiographic findings in patients suspected of subacromial impingement syndrome: prevalence and reliability

OBJECTIVE

Aims were to (i) report prevalence and (ii) evaluate reliability of the radiographic findings in examinations of patients suspected of subacromial impingement syndrome (SIS), performed before a patient's first consultation at orthopaedic department.

MATERIALS AND METHODS

This cross-sectional study examined radiographs from 850 patients, age 18 to 63 years, referred to orthopaedic clinic on suspicion of SIS. Prevalence (%) of radiographic findings were registered. Inter- and intrarater reliability was analysed using expected and observed agreement (%), kappa coefficients, Bland-Altman plots, or intraclass coefficients.

RESULTS

A total of 850 patients with a mean age of 48.2 years (SD = 8.8) were included. Prevalence of the radiographic findings was as follows: calcification 24.4%, Bigliani type III (hooked) acromion 15.8%, lateral/medial acromial spurs 11.1%/6.6%, acromioclavicular osteoarthritis 12.0%, and Bankart/Hill-Sachs lesions 7.1%. Inter- and intrarater Kappa values for most radiographic findings ranged between 0.40 and 0.89; highest values for the presence of calcification (0.85 and 0.89) and acromion type (0.63 and 0.66). The inter- and intrarater intraclass coefficients ranged between 0.41 and 0.83; highest values for acromial tilt (0.79 and 0.83) and calcification area (0.69 and 0.81).

CONCLUSION

Calcification, Bigliani type III (hooked) acromion, and acromioclavicular osteoarthritis were prevalent findings among patients seen in orthopaedic departments on suspicion of SIS. Spurs and Bankart/Hill-Sachs lesions were less common. Optimal reliabilities were found for the presence of calcification, calcification area, and acromial tilt. Calcification qualities, acromion type, lateral spur, and acromioclavicular osteoarthritis showed suboptimal reliabilities. Newer architectural measures (acromion index and lateral acromial angle) performed well with respect to reliability.

High frequency of labral pathology in symptomatic borderline dysplasia: a prospective magnetic resonance arthrography study of 99 patients

Labral pathology is seen in both dysplastic and borderline dysplastic hips. Periacetabular osteotomy (PAO) is the treatment of choice for dysplasia. However, some authors have suggested that borderline dysplastic hips with concurrent labral pathology should be treated arthroscopically. The purpose of this study was to investigate the frequency of labral pathology between dysplastic and borderline dysplastic hips, whether centre-edge (CE) angle is associated with labral pathology, and finally if pain and labral pathology are associated. Ninety-nine symptomatic patients (104 hips) scheduled for PAO were examined. Five patients were excluded due to complaints from multiple joints and four failed to show at 2-year follow-up. Five patients did not fill out questionnaires preoperatively. Hips were characterized as dysplastic (CE angle <20°) and borderline dysplastic (CE angle 20° ≤ 25°). A magnetic resonance arthrography was performed, and labral pathology was classified according to the Czerny classification. Association with the CE angle, the acetabular index (AI) and preoperative WOMAC pain score was tested by multiple linear regression. There was no significant difference in frequency of labral pathology when comparing the two groups. Across the cohort, 86 of 99 patients had labral pathology. The CE angle was associated with increasing severity of labral pathology, whereas the AI angle and preoperative pain were not associated with labral pathology. Decreased lateral coverage adversely loads the labrum, predisposing it to tears. We advocate reorienting the biomechanical forces through PAO, not arthroscopic treatment. Level of pain was not associated with labral pathology, suggesting that labral pathology may not alone explain the dysplastic pain complex.

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.

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.

Risk factors for the need of hip arthroscopy following periacetabular osteotomy

Despite the frequency of labral tears in symptomatic developmental dysplasia of the hip, no consensus exists regarding the treatment of coexisting dysplasia of the hip and tearing of the acetabular labrum. The purpose of this prospective, MR arthrography (MRA) based 2-year follow-up study was to identify risk factors predicting the need for a hip arthroscopy (HA) after periacetabular osteotomy (PAO). Ninety-nine patients (104 hips) scheduled for PAO were evaluated preoperatively and at 2-year follow-up. MRA was performed in all patients prior to PAO. At follow-up, patients were divided into a non-arthroscopy and arthroscopy group. The two groups were compared clinical and radiological, and risk factors for HA after PAO were calculated. Patient reported outcome measures (WOMAC, Oxford Hip and SF36) were filled out before PAO and at follow-up. Ninety-five hips (91.3%) were evaluated. Twenty-six hips (27%) required an arthroscopy within 2 years of the PAO. Risk factors were preoperative borderline dysplasia, acetabular retroversion and complete labral detachment. Labral tearing, degeneration or hypertrophy did not negatively affect the outcome of PAO. Patients not requiring an arthroscopy had a statistically significant better outcome measured by patients reported outcome measures. After PAO, 27% of the hips needed intra-articular assessment. Conventional radiographs and MRA analysis can be used to identify predictors for patients requiring HA after PAO. At 2-year follow-up, the clinical outcome improved in all patients. However, those patients who had no need of a HA after their PAO had superior results.

Cartilage Thickness and Cyst Volume Are Unchanged 10 Years After Periacetabular Osteotomy in Patients Without Hip Symptoms

BACKGROUND

Periacetabular osteotomy (PAO) may affect cartilage thickness and cyst volume in patients with hip dysplasia. However, as no studies randomizing patients to either PAO or conservative treatment have been performed, to our knowledge, it is unknown if PAO directly affects the development or progression of osteoarthritis in patients with hip dysplasia.

QUESTIONS/PURPOSES

We investigated (1) changes of cartilage thickness in the hip after PAO; (2) how many patients had subchondral bone cysts in the acetabulum or femoral head; (3) changes in cyst volume; and (4) patients' hip function and pain after PAO.

PATIENTS AND METHODS

In this prospective study, 26 patients (22 women and four men) with hip dysplasia were enrolled with the goal of having MRI of the hip before undergoing PAO and again at 1, 2½, and 10 years after PAO. Of the 26 patients, 17 (65%) underwent complete followup 10 years after PAO, whereas nine could not be included. Of those nine, three had undergone THA, three had substantial hip symptoms, and three were lost to followup. Thickness of acetabular and femoral cartilage and volume of subchondral bone cysts were estimated in the remaining 17 patients. Ten years postoperatively, the patients' Hip disability and Osteoarthritis Outcome Scores (HOOS) were collected.

RESULTS

Preoperatively, the mean thickness of the acetabular cartilage was 1.38±0.14 mm compared with 1.43±0.07 mm 10 years postoperatively (p=0.73). The mean thickness of the femoral cartilage preoperatively was 1.37±0.20 mm compared with 1.30±0.07 mm 10 years postoperatively (p=0.24). Seven patients had an increase in cyst volume, six had a decrease, and four had no cysts to start with and remained without cysts. Preoperatively, the median total cyst volume per patient was 6.0 cm3 (range, 1.6-188.3 cm3) compared with 2.9 cm3 (range, 0.7-8.2 cm3) (p=0.18) at 10 years followup. At 10 years, the mean subscores for the HOOS were: pain, 79±16; symptoms, 73±17; activities of daily living, 85±14; sport/recreation, 68±22; and quality of life, 61±19.

CONCLUSIONS

Ten years after PAO, approximately 25% of the patients who have the procedure will have substantial hip pain and/or undergo hip arthroplasty. Of the patients who do not have substantial hip pain or an arthroplasty, cartilage thickness appears to be preserved. Future studies are needed to help us decide which patients are most likely to succeed with PAO at long-term followup.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Computed tomography-guided radiofrequency ablation is a safe and effective treatment of osteoid osteoma located outside the spine

INTRODUCTION

The aim of this study was to evaluate the long-term clinical outcome after computed tomography (CT)-guided radiofrequency ablation (RFA) in patients diagnosed with osteoid osteoma (OO) located in the upper and lower extremities.

METHODS

The study population included 52 patients with a typical clinical history and radiologically confirmed OO who received CT-guided RFA treatment from 1998 to February 2014 at Aarhus University Hospital, Denmark. The clinical outcome was evaluated based on patient-reported outcome measures and medical record review.

RESULTS

The response rate was 52/60 (87%). Pain relief after the first RFA treatment was found in 46/52 (88%) of the patients and after re-RFA in 51/52 (98%) of the patients. One patient underwent open resection after RFA. No major complications occurred, and four patients reported minor complications in terms of small skin burn, minor skin infection and hypoaesthesia at the entry point. In all, 50 of 52 (96%) patients reported to be "very satisfied" with the RFA treatment.

CONCLUSION

CT-guided RFA is a safe and effective treatment with high patient satisfaction and it provides robust pain relief and improves the patients' quality of life. RFA should be the treatment of choice for most OO.

FUNDING

not relevant.

TRIAL REGISTRATION

The Danish Data Protection Agency approved the project with record number 2007-58-0010.

Cam deformity and hip degeneration are common after fixation of a slipped capital femoral epiphysis

BACKGROUND AND PURPOSE

Slipped capital femoral epiphysis is thought to result in cam deformity and femoroacetabular impingement. We examined: (1) cam-type deformity, (2) labral degeneration, chondrolabral damage, and osteoarthritic development, and (3) the clinical and patient-reported outcome after fixation of slipped capital femoral epiphysis (SCFE).

METHODS

We identified 28 patients who were treated with fixation of SCFE from 1991 to 1998. 17 patients with 24 affected hips were willing to participate and were evaluated 10-17 years postoperatively. Median age at surgery was 12 (10-14) years. Clinical examination, WOMAC, SF-36 measuring physical and mental function, a structured interview, radiography, and MRI examination were conducted at follow-up.

RESULTS

Median preoperative Southwick angle was 22o (IQR: 12-27). Follow-up radiographs showed cam deformity in 14 of the 24 affected hips and a Tönnis grade>1 in 1 affected hip. MRI showed pathological alpha angles in 15 affected hips, labral degeneration in 13, and chondrolabral damage in 4. Median SF-36 physical score was 54 (IQR: 49-56) and median mental score was 56 (IQR: 54-58). These scores were comparable to those of a Danish population-based cohort of similar age and sex distribution. Median WOMAC score was 100 (IQR: 84-100).

INTERPRETATION

In 17 patients (24 affected hips), we found signs of cam deformity in 18 hips and early stages of joint degeneration in 10 hips. Our observations support the emerging consensus that SCFE is a precursor of cam deformity, FAI, and joint degeneration. Neither clinical examination nor SF-36 or WOMAC scores indicated physical compromise.

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.

What is the role of clinical tests and ultrasound in acetabular labral tear diagnostics?

BACKGROUND AND PURPOSE

An acetabular labral tear is a diagnostic challenge. Various clinical tests have been described, but little is known about their diagnostic sensitivity and specificity. We investigated the diagnostic validity of clinical tests and ultrasound as compared with MR arthrography.

PATIENTS AND METHODS

We examined 18 patients (18 hips, 2 men, median age 43 (32-56) years) with impingement test, FABER test, resisted straight leg raise test, ultrasound, and MR arthrography. They had had previous periacetabular osteotomies due to symptomatic, acetabular dysplasia. All hips showed no or only slight signs of osteoarthritis (Tönnis grade 0-1).

RESULTS

MR arthrography identified labral tears in 17 of the 18 hips. Ultrasound had a sensitivity of 94%, a positive predictive value of 94%, and was false negative in only 1 case compared to MR arthrography. The impingement test had the best diagnostic ability of the clinical tests, with a sensitivity of 59% and a specificity of 100%. The positive predictive value was 100% while the negative predictive value was 13%.

INTERPRETATION

The impingement test is helpful in identifying acetabular labral tears. If this test is negative and if a labral tear is still suspected, ultrasound can reliably diagnose most tears of the acetabular labrum. MR arthrography is indicated in cases where ultrasound is negative, but the patient suffers continued, specific symptoms.

Intra-articular vs. systemic administration of etanercept in antigen-induced arthritis in the temporomandibular joint. Part II: mandibular growth

BACKGROUND

Temporomandibular joint (TMJ) arthritis in children causes alterations in the craniomandibular growth. Resultant abnormalities include; condylar erosions, a posterior mandibular rotation pattern, micrognathia, malocclusion with an anterior open bite, altered joint and muscular function occasionally associated with pain. These alterations may be prevented by early aggressive anti-inflammatory intervention. Previously, we have shown that intra-articular (IA) corticosteroid reduces TMJ inflammation but causes additional mandibular growth inhibition in young rabbits. Local blockage of TNF-alpha may be an alternative treatment approach against TMJ involvement in juvenile idiopathic arthritis (JIA). We evaluated the anti-inflammatory effect of IA etanercept compared to subcutaneous etanercept in antigen-induced TMJ-arthritis in young rabbits in terms of mandibular growth. This article (Part II) presents the data and discussion on the effects on facial growth. In Part I the anti-inflammatory effects of systemic and IA etanercept administration are discussed.

METHODS

Arthritis was induced and maintained in the TMJs of 10-week old pre-sensitized rabbits (n = 42) by four repeated IA TMJ injections with ovalbumin, over a 12-week period. One group was treated weekly with systemic etanercept (0.8 mg/kg) (n = 14), another group (n = 14) received IA etanercept (0.1 mg/kg) bilaterally one week after induction of arthritis and one group (n = 14) served as an untreated arthritis group receiving IA TMJ saline injections. Head computerized tomographic scans were done before arthritis was induced and at the end of the study. Three small tantalum implants were inserted into the mandible, serving as stable landmarks for the super-impositions. Nineteen variables were evaluated in a mandibular growth analysis for inter-group differences. All data was evaluated blindedly. ANOVA and T-tests were applied for statistical evaluation using p < 0.05 as significance level.

RESULTS

Significant larger mandibular growth disturbances were observed in the group receiving IA saline injections compared with the systemic etanercept group. The most pronounced unfavourable posterior mandibular rotation pattern was observed in the group receiving IA saline injections.

CONCLUSION

Intervention with systemic etanercept monotherapy equivalent to the recommended human dose allows a mandibular growth towards an original morphology in experimental TMJ arthritis. Systemic administrations of etanercept are superior to IA TMJ administration of etanercept in maintaining mandibular vertical growth.

A prospective study of magnetic resonance and radiographic imaging in relation to symptoms and clinical findings of the temporomandibular joint in children with juvenile idiopathic arthritis

OBJECTIVE

In patients with juvenile idiopathic arthritis (JIA) temporomandibular joint (TMJ) involvement is a common cause of severe growth disturbances. Extent of growth deviation depends on age of onset and duration of arthritis in the TMJ. TMJ arthritis is difficult to diagnose at an early stage since relatively few symptoms and clinical findings are related to this joint. The pathologic process can affect growth long before radiographic changes are seen. We investigated the relationship between TMJ arthritis and symptoms and clinical findings to suggest a clinical routine for diagnosing TMJ arthritis. We also describe the course of TMJ arthritis in relation to a commonly used radiographic method versus MRI.

METHODS

Fifteen children with JIA were examined 4 times at 6 month intervals for TMJ involvement by clinical examination, MRI-scanning, and orthopantomograms (OPG). At baseline, 10 healthy children served as a control group.

RESULTS

Patients reported more inability to chew and open their mouth than the control group. Translation of the condyle and range of mandibular movements were diminished in the arthritis group. Decreased translation was correlated to condylar changes seen on both OPG and MRI. MRI was superior to OPG in following changes of the condyle over time, and inflammation was detected in nearly all joints.

CONCLUSION

OPG cannot be recommended for diagnosis or to follow the course of changes in the TMJ. We advocate recording condylar translation and mandibular range of motion as a current clinical routine to find early TMJ arthritis in contrast to the often used OPG performed in our study, which was an uncertain method.

Reduced mandibular growth in experimental arthritis in the temporomandibular joint treated with intra-articular corticosteroid

The aim of this investigation was to study the effect of intra-articular (i.a.) corticosteroid injections (IACIs) in the temporomandibular joint (TMJ) on mandibular development in antigen-induced TMJ arthritis. Ten-week-old female New Zealand white rabbits (n = 42) were randomly divided into four groups: group A, control (no injections); group B, placebo (repeated i.a. TMJ saline injections); group C, untreated arthritis (repeated induction of TMJ arthritis); and group D, steroid (repeated induction of TMJ arthritis + IACI). All animals had two tantalum implants inserted in the right side of the mandible serving as stable landmarks for later growth analysis. One implant was inserted close to the symphysis and one in the molar region. Computerized tomographic (CT) full-head scans were carried out at 14 (T1) and 26 (T2) weeks of age. (Dropout of animals at T2; group C, n = 7, and group D, n = 3.) Absolute and relative intra- and inter-group growth variations were evaluated during the growth period by comparison of CT scans. One-way analysis of variance was used for T1 statistical analysis, and absolute intra-group and relative inter-group growth differences between T1 and T2 were evaluated by Student's t-tests. At T2, the animals in the group A had greater sagittal and vertical mandibular growth compared with the other three groups. TMJ arthritis caused diminished mandibular growth. However, relative mandibular growth was significantly less in group D. The findings of this study do not indicate a positive long-term effect in the use of IACI in the TMJ as an early treatment intervention against TMJ inflammation in growing individuals.

MRI-guided 3D optimization significantly improves DVH parameters of pulsed-dose-rate brachytherapy in locally advanced cervical cancer

PURPOSE

To compare dose-volume histogram parameters of standard Point A and magnetic resonance imaging-based three-dimensional optimized dose plans in 21 consecutive patients who underwent pulsed-dose-rate brachytherapy (PDR-BT) for locally advanced cervical cancer.

METHODS AND MATERIALS

All patients received external beam radiotherapy (elective target dose, 45 Gy in 25-30 fractions; tumor target dose, 50-60 Gy in 25-30 fractions). PDR-BT was applied with a tandem-ring applicator. Additional ring-guided titanium needles were used in 4 patients and a multichannel vaginal cylinder in 2 patients. Dose planning was done using 1.5 Tesla T(1)-weighted and T(2)-weighted paratransversal magnetic resonance imaging scans. T(1)-weighted visible oil-containing tubes were used for applicator reconstruction. The prescribed standard dose for PDR-BT was 10 Gy (1 Gy/pulse, 1 pulse/h) for two to three fractions to reach a physical dose of 80 Gy to Point A. The total dose (external beam radiotherapy plus brachytherapy) was normalized to an equivalent dose in 2-Gy fractions using alpha/beta = 10 Gy for tumor, alpha/beta = 3 Gy for normal tissue, and a repair half-time of 1.5 h. The goal of optimization was dose received by 90% of the target volume (D(90)) of > or =85 Gy(alpha/beta10) in the high-risk clinical target volume (cervix and remaining tumor at brachytherapy), but keeping the minimal dose to 2 cm(3) of the bladder and rectum/sigmoid at <90 and <75 Gy(alpha/beta3), respectively.

RESULTS

Using three-dimensional optimization, all dose-volume histogram constraints were met in 16 of 21 patients compared with 3 of 21 patients with two-dimensional library plans (p < 0.001). Optimization increased the minimal target dose (D(100)) of the high-risk clinical target volume (p < 0.007) and decreased the minimal dose to 2 cm(3) for the sigmoid significantly (p = 0.03). For the high-risk clinical target volume, D(90) was 91 +/- 8 Gy(alpha/beta10) and D(100) was 76 +/- 5 Gy(alpha/beta10). The minimal dose to 2 cm(3) for the bladder, rectum, and sigmoid was 73 +/- 6, 67 +/- 6, and 69 +/- 6 Gy(alpha/beta3), respectively.

CONCLUSION

The results of our study have shown that magnetic resonance imaging-guided optimization of PDR-BT for locally advanced cervical cancer significantly improved the dose-volume histogram parameters.

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.

Permanent disabilities in the displaced muscle from rupture of the long head tendon of the biceps

Patients with a displaced muscle belly because of rupture of the long head biceps tendon were investigated for local pain and other disabilities, together with strength and endurance loss. Eleven patients (median age 59 years, minimum follow-up 6 months) were included, and minimum follow-up was 6 months. Magnetic resonance imaging (MRI) of both upper arms allowed investigation of muscle atrophy and evaluation of any other degenerative signs in the displaced muscle. All patients reported pain or disability locally in the displaced muscle in certain situations, and strength and endurance were reduced by 25%. MRI revealed the displaced muscle to be unreduced in size and with no signs of degeneration. Generally, operative reattachment of the displaced muscle is not advocated in middle-aged or older patients. In order to elucidate this subject, we present a retrospective consecutive series of patients with considerable disabilities in the displaced muscle belly independent of shoulder disabilities.

A 2 year followup study of enhanced magnetic resonance imaging and clinical examination of the temporomandibular joint in children with juvenile idiopathic arthritis

OBJECTIVE

Involvement of the temporomandibular joint (TMJ) in patients with juvenile idiopathic arthritis (JIA) can cause severe craniofacial growth disturbances if not treated in the initial stage. Magnetic resonance imaging (MRI) is an efficient method for detecting early inflammatory changes of the TMJ. We investigated correlation between findings from the clinical examination with MRI of the TMJ, and describe development of the MR image over time.

METHODS

Fifteen children with newly diagnosed JIA (mean age 12.0 yrs) were examined clinically and with MRI enhanced with Gd-DTPA 4 times at 6-8 month intervals. Clinical and MRI findings were scored. MRI variables included T1 weighted images before and after administration of Gd-DTPA with and without fat suppression.

RESULTS

A total of 115 joints were examined during the 2 year period: 93% showed enhancement, 71% condylar erosions, 26% pannus, and 23% joint fluid accumulation of the TMJ. In all except one child, one or both TMJ showed enhancement of the synovial membrane during the examination period. Symptoms were rare. All patients showing mild to severe findings by clinical examination also had pathological signs on the enhanced MRI, but not all patients without clinical findings had a normal MRI.

CONCLUSION

TMJ involvement in patients with JIA is very common, and MRI findings such as synovial enhancement, pannus, and joint fluid fluctuate over time. The clinical examination may be used as a filter, where children showing no clinical signs could be selected for enhanced MRI.

Work above shoulder level and degenerative alterations of the rotator cuff tendons: A magnetic resonance imaging study

OBJECTIVE

To determine whether work performed with the arms in a highly elevated position is associated with alterations in the rotator cuff tendons as assessed by magnetic resonance imaging (MRI).

METHODS

A cross-sectional study was performed in a historical cohort of male machinists, car mechanics, and house painters. The participants were right-handed, ages 40-50 years, and had been employed in their trades for not less than 10 years. Seventy-one percent of invited subjects participated (136 of 192). Lifetime upper arm elevation was assessed by direct measurements combined with individual work histories obtained by questionnaire and from registry data. Supraspinatus tendinopathy was evidenced by MRI signal intensity changes and morphologic alterations. Infraspinatus and subscapularis tendinopathy were also assessed. Additional outcomes were acromioclavicular joint degeneration and humeral head cysts. The MRI findings were evaluated by radiologists who were blinded to exposure status and symptoms.

RESULTS

An exposure-response relationship was found between lifetime upper arm elevation and supraspinatus tendinopathy, with an age-adjusted odds ratio of 1.27 (95% confidence interval 1.02-1.60) for a 5-month increase in the total number of full-time working months spent with the arm elevated >90 degrees .

CONCLUSION

Work with the arms in a highly elevated position is associated with MRI-diagnosed alterations in the supraspinatus tendon. By demonstrating the first part of a possible biologic pathway, the study corroborates the work-relatedness of rotator cuff disorders.

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.

In vitro osteoblast-like cell metabolism in spondylodesis--a tool that may predict fusion capacity: a prospective study in 50 patients with a 1-year follow-up

In vitro cultures of human primary osteoblast-like cells provide a model for studying cellular mechanisms associated with human bone biology. We investigated in vitro osteoblast-like cell metabolism as a method for predicting the occurrence of spinal fusion in the individual patient. A bone biopsy was taken from the iliac crest of 50 patients, median age 49 (23-77) years, who were undergoing lumbar spine fusion. First-passage osteoblast-like cells were established by the bone-tissue-explant method. We then estimated 3H-thymidine incorporation, alkaline phosphatase activity and procollagen I production. Fusion rates were evaluated at the 1-year follow-up. Primary human osteoblast-like cell cultures showed an age-dependent decline in their capacity for cellular outgrowth and expression of alkaline phosphatase, which suggested a useful biological response pattern of the osteoblast culture. However, such cultures were unsatisfactory as an in vitro tool for predicting fusion capacity.

In vitro osteoblast proliferation as a predictor for spinal fusion mass

BACKGROUND CONTEXT

The biological factors determining a successful spinal fusion have not yet been fully determined.

PURPOSE

To determine the influence of graft cell vigor on fusion rate and fusion mass using in vitro osteoblast proliferation as a predictor.

STUDY DESIGN

Animal study randomizing to posterolateral fusion with autograft with or without pedicle-screw instrumentation.

PATIENT SAMPLE

Twenty adult Göttingen mini-pigs.

OUTCOME MEASURES

Fusion rate measured both with X-ray and computed tomography (CT) as well as amount of fusion mass determined with three-dimensional CT.

METHODS

Animals underwent posterolateral fusion with autograft either with or without pedicle-screw instrumentation. Additional graft was harvested for osteoblastlike cell culture. Cells were counted after 3 weeks, and their proliferative capacity was correlated to fusion rate and fusion amount.

RESULTS

Cell count was significantly higher in the fused animals (p<.011). Furthermore, a tendency toward a positive correlation to fusion mass amount was observed (p<.091).

CONCLUSIONS

The achievement of a solid spinal fusion using autograft is related to properties of the bone-forming cells in the graft and fusion bed. Most likely it is the number of cells and not their proliferative capacity that is the most important factor.

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.

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.

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.

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.

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.

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]

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]

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.

Fractures of the femoral neck treated with cemented bipolar hemiarthroplasty

Seven of 59 (12%) bipolar hemiarthroplasties for displaced femoral neck fracture were classified as failures at the 3-year follow-up examination. Two prostheses dislocated, 4 had loose femoral stems, and 1 was revised to a total hip arthroplasty because of pain. No patients developed acetabular erosion or deep infection. Only four of 15 patients examined by fluoroscopy shared movement between outer metal/cartilage and inner metal/polyethylene surfaces. All movement occurred at the outer metal/cartilage surface in the remaining nine patients. We conclude that the low failure rate, which compares favorably with the best results after internal fixation, is caused by the optimal selection of patients for this operation (high age, low activity level) and the use of bone cement. The bipolar design is less important, since most of these prostheses function as ordinary unipolar prostheses after some time.

Component motion in bipolar cemented hemiarthroplasty

A total of 17 patients with a cemented bipolar Hastings hemiarthroplasty were examined clinically and radiologically between 1 and 3 years after being treated for a displaced femoral neck fracture. Only a minor part of the motion in the Hastings prostheses took place between the metal femoral head and the polyethylene liner (intraprosthetic). In seven cases, no "true" intraprosthetic motion weightbearing was observed (including five cases with intraprosthetic motion caused by impingement). The relative amount of intraprosthetic motion did not decrease with weightbearing. The functional result was not correlated to the relative amount of intraprosthetic motion with weightbearing. In conclusion, the short-term success of the bipolar prostheses is probably not accomplished by a reduction in extraprosthetic motion caused by the biarticular design but by other factors, including the optimal indications for hemiarthroplasty (high age, low activity level), the consistent use of acrylic bone cement, and the shock-absorbing effect of the polyethylene liner.

Poor function after nonoperative treatment of Kienböck's disease

Twenty-five wrist joints treated with immobilization for Kienböck's disease were reexamined after 8 (1-11) years. Six patients had no pain, but 14 had daily problems with the wrist, and of these, 7 had to change their occupation. Five wrist joints were arthrodesed during the follow-up period. We conclude that nonoperative treatment of Kienböck's disease is ineffective.