Imaging of symptomatic total knee arthroplasty with cone beam computed tomography.

BACKGROUND: Computed tomography (CT) can be used to assess the rotational alignment of prosthesis components to identify possible underlying causes of symptomatic total knee arthroplasty (TKA). The use of cone beam computed tomography (CBCT) for the imaging of extremities is relatively new, although it has been widely used in dental imaging. PURPOSE: To assess the intra- and inter-observer reproducibility of CBCT, as well as to validate CBCT for TKA component and periprosthetic bone diagnostics. MATERIAL AND METHODS: CBCT scans were performed on 18 patients the day before a scheduled revision TKA, from which the intra- and inter-observer reproducibility were assessed. Component rotation and loosening were evaluated. Perioperative bone defects were classified. RESULTS: The inter-observer intraclass coefficient correlation (ICC) for femoral component rotation was 0.41 (95% confidence interval [CI] = 0.12-0.69). For the tibial component, the ICC was 0.87 (95% CI = 0.74-0.94). Intra-observer reproducibilities were 0.70 (95% CI = 0.35-0.87) and 0.92 (95% CI = 0.80-0.97), respectively. The sensitivity for tibial component loosening was 97% and the specificity was 85%. The reliability of bone defect classification was only weak to moderate. CONCLUSION: Two-dimensional (2D) CBCT scanning provides reliable and reproducible data for determining the rotation of femoral and tibial components, while showing minor overestimation of tibial component loosening. CBCT is a promising new tool for the evaluation of symptomatic knee arthroplasty patients, with a substantially lower radiation dose compared to conventional 2D multi-slice CT.

Results of Operative and Nonoperative Treatment of Rockwood Types III and V Acromioclavicular Joint Dislocation: A Prospective, Randomized Trial With an 18- to 20-Year Follow-up.

BACKGROUND: The optimal treatment of acute, complete dislocation of the acromioclavicular joint (ACJ) is still unresolved. PURPOSE: To determine the difference between operative and nonoperative treatment in acute Rockwood types III and V ACJ dislocation. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: In the operative treatment group, the ACJ was reduced and fixed with 2 transarticular Kirschner wires and ACJ ligament suturing. The Kirschner wires were extracted after 6 weeks. Nonoperatively treated patients received a reduction splint for 4 weeks. At the 18- to 20-year follow-up, the Constant, University of California at Los Angeles Shoulder Rating Scale (UCLA), Larsen, and Simple Shoulder Test (SST) scores were obtained, and clinical and radiographic examinations of both shoulders were performed. RESULTS: Twenty-five of 35 potential patients were examined at the 18- to 20-year follow-up. There were 11 patients with Rockwood type III and 14 with type V dislocations. Delayed surgical treatment for ACJ was used in 2 patients during follow-up: 1 in the operatively treated group and 1 in the nonoperatively treated group. Clinically, ACJs were statistically significantly less prominent or unstable in the operative group than in the nonoperative group (normal/prominent/unstable: 9/4/3 and 0/6/3, respectively; P = .02) and in the operative type III (P = .03) but not type V dislocation groups. In operatively and nonoperatively treated patients, the mean Constant scores were 83 and 85, UCLA scores 25 and 27, Larsen scores 11 and 11, and SST scores 11 and 12 at follow-up, respectively. There were no statistically significant differences in type III and type V dislocations. In the radiographic analysis, the ACJ was wider in the nonoperative than the operative group (8.3 vs 3.4 mm; P = .004), and in the type V dislocations (nonoperative vs operative: 8.5 vs 2.4 mm; P = .007). There was no statistically significant difference between study groups in the elevation of the lateral end of the clavicle. Both groups showed equal levels of radiologic signs of ACJ osteoarthritis and calcification of the coracoclavicular ligaments. CONCLUSION: Nonoperative treatment was shown to produce more prominent or unstable and radiographically wider ACJs than was operative treatment, but clinical results were equally good in the study groups at 18- to 20-year follow-up. Both treatment methods showed statistically significant radiographic elevations of the lateral clavicle when compared with a noninjured ACJ.

Sample size for prospective studies of hip joint space width narrowing in osteoarthritis by the use of radiographs.

OBJECTIVE: To determine the number of participants required in controlled clinical trials investigating the progression of osteoarthritis (OA) of the hip as evaluated by the joint space width (JSW) on radiographs and to evaluate the reproducibility of the JSW measurement methods. MATERIALS AND METHODS: Anteroposterior radiographs of hip were taken from 13 healthy volunteers and from 18 subjects with radiographic hip OA. The reproducibility of the JSW was determined from four segments using digital caliper measurements performed on film radiographs and using semiautomatic computerized image analysis of digitized images. Pearson correlation coefficient, coefficient of variability [CV (%)], and sample size values were calculated. RESULTS: It was found that 20 was a typical number of patients for a sufficiently powered study. The highest sample size was found in subjects with OA in the lateral segment. The reproducibility of the semiautomatic computerized method was not significantly better than the digital caliper method. CONCLUSION: The number of study subjects required to detect a significant joint space narrowing in follow-up studies is influenced by the baseline hip joint OA severity. The JSW measurements with computerized image analysis did not improve the reproducibility and thus performing JSW measurements with a digital caliper is acceptable.

Detection and quantification of rotator cuff tears with ultrasonography and magnetic resonance imaging - a prospective study in 77 consecutive patients with a surgical reference.

The aim of this study was to compare the accuracy of ultrasonography (US) and magnetic resonance artrography (MRA) for the detection and measurement of rotator cuff tears, using surgical findings as a standard. A total of 77 consecutive patients with suspected rotator cuff tears were prospectively studied with US and MRA. Rotator cuff tears were identified by US with sensitivity, specificity, positive predictive and negative predictive values of 92%, 45%, 91% and 50%, respectively, and by MRA with values of 97%, 82%, 97% and 82%, respectively. US was not reliable for differentiating between partial and full thickness tears. US and MRA underestimated the tear sizes by an average of 15 mm and 4 mm, respectively. Our results suggest that US could be used as a screening test to confirm a suspected rotator cuff tear. In patients with negative findings, an MRA should be considered for substantiation.

Progression of kidney disease varies between families with defects in the polycystic kidney disease type 1 gene in eastern Finland.

OBJECTIVE: To characterize, for the first time, the phenotype and clinical course of autosomal dominant polycystic kidney disease (ADPKD) in Finnish patients. MATERIAL AND METHODS: All patients underwent an abdominal sonographic examination and most of those with ADPKD underwent magnetic resonance angiography of the head. Haplotype analysis was used to classify 20 ADPKD families into those with defects in either the polycystic kidney disease type 1 (PKD1) or polycystic kidney disease type 2 (PKD2) genes. Evaluation of the rate of progression of kidney disease in patients with ADPKD was based on creatinine values. RESULTS: Haplotype analysis showed that 16 families had defects in the PKD1 gene and one had defects in the PKD2 gene. Three families were excluded because of uninformative haplotypes. The final study population consisted of 79 unaffected family members, 109 patients with defects in the PKD1 gene and 10 with defects in the PKD2 gene. Higher prevalences of hepatic cysts (3% in healthy relatives, 60% in PKD1 patients and 90% in PKD2 patients; p < 0.001), subarachnoid hemorrhage or cerebral aneurysms (1%, 12% and 0%, respectively; p < 0.001), proteinuria (1%, 23% and 0%, respectively; p < 0.001) and hematuria (5%, 30% and 0%, respectively; p < 0.001) were found in PKD1 patients compared to the healthy relatives. PKD1 patients had a faster progression of kidney disease than PKD2 patients (p < 0.001). The progression of kidney disease varied substantially among the PKD1 families. CONCLUSION: The relative proportions of PKD1 and PKD2 patients and the phenotype of ADPKD were similar in our Finnish patients compared to previous studies in other populations. However, the progression of kidney disease differed substantially among PKD1 families, indicating a heterogeneic genetic background of PKD1 in Finnish patients.

Insulin resistance is related to left ventricular hypertrophy in patients with polycystic kidney disease type 1.

BACKGROUND: Left ventricular hypertrophy (LVH) is common in patients with autosomal dominant polycystic kidney disease (ADPKD). Although insulin resistance contributes to cardiac hypertrophy, the relationship between insulin resistance and LVH in patients with ADPKD has not been previously studied. METHODS: We performed M-mode and color Doppler echocardiography on 176 family members (106 patients and 70 healthy relatives) from 16 families with polycystic kidney disease type 1 (PKD1). Left ventricular mass index (LVMI) was calculated using the Penn equation and corrected for body surface area. Fasting insulin and glucose concentrations were measured and insulin resistance was evaluated by means of the homeostasis model assessment. RESULTS: In multivariate regression analysis, insulin resistance was significantly associated with LVMI in healthy relatives (P < 0.01) and patients with PKD1 (P < 0.05) independent of age, weight, systolic blood pressure, and albuminuria. CONCLUSION: Insulin resistance is associated with LVMI in patients with PKD1 independently of other factors known to increase LVMI.

Comparison of DXA and MRI methods for interpreting femoral neck bone mineral density.

The aim of the study was to improve the practical implementation of the dual X-ray absorptiometry (DXA) by converting the areal bone mineral density BMD (BMD(areal)) to volumetric BMD using magnetic resonance (MR) imaging (MRI) because a failure to control for the femoral neck size can lead to erroneous interpretation of BMD values. We also evaluated the feasibility of MR T2* relaxation time in assessing bone mineral status of the femoral neck. Twenty-eight randomly selected 47- to 64-yr-old healthy men were studied. The men had neither unilateral nor bilateral hip osteoarthritis according to radiographs. Bone width, mineral content (BMC), BMD(areal), and apparent volumetric BMD (BMD(vol)) of the right femoral neck were measured with DXA. The BMD(vol) was calculated by approximating the femoral neck to be cylindrical with a circular cross-section (Vol(dxa)). Volumetric measurements from MR (Vol(mri)) images of the femoral neck were also used to create a BMD measure that was corrected for the femoral neck volume (BMD(mri)). T2* measurements were performed with a 1.5-T scanner (Siemens Magnetom 63SP, Erlangen, Germany). A single 10-mm-thick coronal slice was generated on the femur with a repetition time of 60 ms, and nine echo times (4-20 ms) were used to derive T2* values. Vol(mri) correlated positively (r = 0.828, p < 0.001) with Vol(dxa). However, the Vol(mri) of the femoral neck was 18% lower than the Vol(dxa). Similarly, the BMD(mri) was related to the BMD(vol) (r = 0.737, p < 0.001). Because of the difference in the volumetric measures, the BMD(mri) of the femoral neck was 21% higher than the BMD(vol) (p < 0.001). T2* relaxation time showed a significant negative correlation with BMC, BMD(areal), BMD(vol), and BMD(mri) (r = -0.423 to -0.757, p < 0.05-0.001). In conclusion, these results are evidence that DXA-derived volume approximations by the cylinder with circular cross-section geometry may lead to lower DXA-derived BMD(vol) values, as compared to true MRI-derived volumetric bone mineral density. Thus, the BMD(vol) may not be an accurate method to calculate the true volumetric BMD in the femoral neck. Our results also suggest that the MRI-derived T2* method may be used to approximate the BMD in the proximal femur.

Hip muscle strength and muscle cross sectional area in men with and without hip osteoarthritis.

OBJECTIVE: To study the hip muscle strength and cross sectional area (CSA) in men with hip osteoarthritis (OA) compared to age and sex matched healthy controls. METHODS: Based on the American College of Rheumatology criteria regarding classification of hip OA, 27 men (aged 47-64 yrs) with unilateral or bilateral hip OA and 30 age matched randomly selected healthy male controls were studied. The maximal isometric hip abductor, adductor, flexor, and extensor strength (Nm) at 0 degree of hip flexion in the supine position was determined with a dynamometer. The isokinetic hip flexion and extension strength (peak torque, Nm) was determined using angular velocities of 60 degrees /s and 120 degrees /s. The subjective severity of hip pain was rated by visual analog scale prior to the muscle strength test. CSA of the pelvic and thigh muscles was measured from magnetic resonance images. RESULTS: The reliability of intraclass correlation coefficients for repeated measures of muscle strength varied from 0.70 to 0.94 in controls and from 0.84 to 0.98 in subjects with OA. Hip isometric adductor and abductor strength was 25% and 31% lower (p < 0.001) in OA subjects than in controls, respectively. The hip isometric and isokinetic flexion strength was 18-22% lower (p < 0.01) in OA subjects than in controls, but extension strength did not differ between groups. In OA subjects, the hip flexion and extension isometric and isokinetic strength values were 13-22% lower (p < 0.05) on the more deteriorated side compared to the better side. CSA of the pelvic and thigh muscles did not differ between the groups. However, in OA subjects, the CSA of the pelvic and thigh muscles was 6-13% less (p < 0.05 to < 0.001) on the more severely affected hip compared to the better hip. CONCLUSION: Men with hip OA have significantly lower abduction, adduction, and flexion muscle strength than controls. The decrease of muscle size and hip pain may contribute to the decrease of muscle strength in hip OA. Other possible underlying causes of the muscle weakness need to be studied.