Magnetic resonance imaging (MRI) versus single photon emission computed tomography (SPECT/CT) in painful total hip arthroplasty: a comparative multi-institutional analysis.

OBJECTIVE: To investigate the value of MRI in comparison to single photon emission computed tomography (SPECT)/CT in patients with painful hip arthroplasties. METHODS: A prospective, multi-institutional study was performed. Therefore, 35 consecutive patients (21 female, 14 male, mean age 61.8 ± 13.3 years) with 37-painful hip arthroplasties were included. A hip surgeon noted the most likely diagnosis based on clinical examination and hip radiographs. Then, MRI and SPECT/CT of the painful hips were acquired. MRI and SPECT/CT were assessed for loosening, infection, fracture, tendon pathology and other abnormalities. Final diagnosis and therapy was established by the hip surgeon after integration of MRI and SPECT/CT results. The value of MRI and SPECT/CT for diagnosis was assessed with a 3-point scale (1 = unimportant, 2 = helpful, 3 = essential). RESULTS: Loosening was observed in 13/37 arthroplasties (6 shaft only, 6 cup only, 1 combined). Sensitivity, specificity, positive predictive value and negative predictive value for loosening of MRI were 86%/88%/60%/100% and of SPECT/CT 93%/97%/90%/100%, respectively. MRI and SPECT/CT diagnosed infection correctly in two of three patients and fractures in two patients, which were missed by X-ray. MRI detected soft tissue abnormalities in 21 patients (6 bursitis, 14 tendon lesions, 1 pseudotumor), of which only 1 tendon abnormality was accurately detected with SPECT/CT. All 5 arthroplasties with polyethylene wear were correctly diagnosed clinically and with both imaging modalities. MRI and SPECT/CT were judged as not helpful in 0/0%, as helpful in 16%/49% and essential in 84%/51%. CONCLUSION: In patients with painful hip arthroplasty SPECT/CT is slightly superior to MR in the assessment of loosening. MRI is far superior in the detection of soft tissue, especially tendon pathologies. ADVANCES IN KNOWLEDGE: To our knowledge this is the first prospective, multiinstitutional study which compares MRI with SPECT/CT in painful hip arthroplasties. We found that MRI is far superior in the detection of soft tissue pathologies, whereas SPECT/CT remains slightly superior regarding loosening.

Maintenance of bone mineral density after implantation of a femoral neck hip prosthesis.

BACKGROUND: Stress shielding of the proximal femur has been observed in a number of conventional cementless implants used in total hip arthroplasty. Short femoral-neck implants are claiming less interference with the biomechanics of the proximal femur. The goal of this study was to investigate the changes of bone-mineral density in the proximal femur and the clinical outcome after implantation of a short femoral-neck prosthesis. METHODS: We prospectively assessed the clinical outcome and the changes of bone mineral density of the proximal femur up to one year after implantation of a short femoral neck prosthesis in 20 patients with a mean age of 47 years (range 17 to 65). Clinical outcome was assessed using the Harris Hip Score. The WOMAC was used as a patient-relevant outcome-measure. The bone mineral density was determined using dual energy x-ray absorptiometry, performed 10 days, three months and 12 months after surgery. RESULTS: The Harris Hip Score improved from an average preoperative score of 46 to a postoperative score at 12 months of 89 points, the global WOMAC index from 5,3 preoperatively to 0,8 at 12 months postoperatively. In contrast to conventional implants, the DEXA-scans overall revealed a slight increase of bone mineral density in the proximal femur in the 12 months following the implantation. CONCLUSION: The short femoral neck stem lead to a distinct bone reaction. This was significantly different when compared to the changes in bone mineral density reported after implantation of conventional implants.

Reliability of the Crowe und Hartofilakidis classifications used in the assessment of the adult dysplastic hip.

OBJECTIVE: To assess the inter-observer and intra-observer reliability of two commonly used radiographic classification systems in the evaluation of hip dysplasia in skeletally mature adults. DESIGN: Three observers with different levels of training independently classified 62 dysplastic hips on 51 standard anteriorposterior pelvis radiographs according to the criteria defined by Crowe and by Hartofilakidis. To assess intra-observer reliability, the same radiographs were reviewed 3 months later by the same observers. PATIENTS: At the time of the radiographic examination, the mean age of the 51 patients had been 54 years (range 18-82 years). RESULTS: A high correlation concerning the inter- and intra-observer reliability of both systems was demonstrated. Inter-observer reliability displayed a weighted kappa coefficient of 0.82 for the Crowe and 0.75 for the Hartofilakidis classification. Intra-observer reliability showed a kappa coefficient of 0.86 and 0.79, respectively. CONCLUSIONS: Both classification systems can be recommended to compare collectives of adult patients with congenital dysplasia of the hip. However, for future clinical practice, it would be advisable to agree on one universally accepted system as a standard in the literature.

Assessment of femoral component migration in total hip arthroplasty: digital measurements compared to RSA.

The aim of this study was to determine the accuracy of the software system "Düsseldorf Migration Analysis - Femoral Component Analysis" (DMA-FCA) in measuring stem migration in total hip arthroplasty (THA) on digitised anteroposterior radiographs of the pelvis. Bony and implant landmarks on two consecutive radiographs were used for measurements of subsidence and varus-valgus tilt. The accuracy of the method was determined by reference to radiostereometric measurements (RSA). Using specific comparability limits, comparability analysis of radiographs with respect to femoral positioning is possible with DMA. DMA-FCA and RSA measurements were performed after cementless THR in a population of 60 patients aged 38 to 69 years. With a Cronbach's alpha-index of 0.89 and 0.99 for subsidence and 0.90 and 0.98 for classic varus-valgus-tilt, the intraobserver and interobserver reliability for the DMA-FCA-method was calculated as good. Using RSA as reference method, the accuracy of DMA-FCA was calculated to be 2.51 mm for subsidence and 2.49 degrees for varus-valgus-tilt (95% confidence interval). Without comparison to RSA, DMA measured 1.94 mm for subsidence and 2.35 degrees for varus-valgus-tilt. Based on a comparison with RSA, our results show lower accuracy for DMA-FCA than for EBRA-FCA, but DMA-FCA is easier to use in everyday clinical practice. It is hoped that the use of digital measuring methods such as DMA will become standard for long-term observation and will be integrated into clinical routine in the context of quality assurance of THR.

Robotic total knee arthroplasty: the accuracy of CT-based component placement.

BACKGROUND: Accurate alignment of the components in total knee arthroplasty is important. By use of postoperative CT controls, we studied the ability of a robotic effector to accurately place and align total knee arthroplasty (TKA) components according to a purely CT-based preoperative plan. PATIENTS AND METHODS: Robotic TKA was performed in 13 patients (6 men) with primary gonarthrosis. Locator screws were placed into femur and tibia under spinal anesthesia. A CT-scan including the femoral head, knee and ankle was performed. In the preoperative planning software, virtual components were positioned into the CT volume. In a second operation, the robot milled femur and tibia with a high-speed milling tool according to the preoperative plan. On the 10th day, CT controls were performed following the same protocol as preoperatively. RESULTS: The mean deviation of the postoperative from the preoperatively planned mechanical axis was 0.2 degrees (95% CI: -0.1 degrees to 0.5 degrees ). The accuracy of angular component placement in frontal, sagittal and transverse planes was within +/-1.2 degrees , and the accuracy of linear component placement in mediolateral, dorsoventral and caudocranial directions was within +/-1.1 mm. INTERPRETATION: Robotic TKA allows placement of components with unparalleled accuracy, but further development is mandatory to integrate soft-tissue balancing into the procedure and make it faster, easier and cheaper.

Repetitive low-energy shock wave treatment for chronic lateral epicondylitis in tennis players.

BACKGROUND: There is conflicting evidence regarding extracorporeal shock wave treatment for chronic tennis elbow. HYPOTHESIS: Treatment with repetitive low-energy extracorporeal shock wave treatment is superior to repetitive placebo extra-corporeal shock wave treatment. METHODS: Seventy-eight patients enrolled in a placebo-controlled trial. All patients were tennis players with recalcitrant MRI-confirmed tennis elbow of at least 12 months' duration. Patients were randomly assigned to receive either active low-energy extracorporeal shock wave treatment given weekly for 3 weeks (treatment group 1) or an identical placebo extracorporeal shock wave treatment (sham group 2). Main outcome measure was pain during resisted wrist extension at 3 months; secondary measures were >50% reduction of pain and the Upper Extremity Function Scale. RESULTS: At 3 months, there was a significantly higher improvement in pain during resisted wrist extension in group 1 than in group 2 (mean [SD] improvement, 3.5 [2.0] and 2.0 [1.9]; P =.001 for between-group difference of improvement) and in the Upper Extremity Function Scale (mean [SD] improvement, 23.4 [14.8] and 10.9 [14.9]; P <.001 for between-group difference of improvement). In the treatment group, 65% of patients achieved at least a 50% reduction of pain, compared with 28% of patients in the sham group (P =.001 for between-group difference). CONCLUSION: Low-energy extracorporeal shock wave treatment as applied is superior to sham treatment for tennis elbow.

Complications after total knee arthroplasty: a comprehensive report.

In most reports of complications following TKA, the method of assessment and report of complications is not defined specifically. It is thus unclear whether certain complications did not occur or were simply not assessed at all. A detailed list of possible complications following TKA was developed, and the occurence of complications in 567 primary TKAs was followed up meticulously according to this list for one year postoperatively. The proportion of knees with complications was 23.6%. A revision operation was performed in 5.6%. The most frequent complication was delayed wound healing. Only a worldwide accepted standard list of well-defined complications will allow comparison of future studies on complications in TKA. For purposes of quality control, the amount of detail recorded must be weighed carefully against its practical value.

The internal calcar septum and its contact with the virtual stem in THR: a computer tomographic evaluation.

The internal calcar septum is a ridge of cortical bone protruding from the inner cortical wall of the proximal femur into the medullary canal. It extends from the lesser trochanter into the femoral neck and narrows the femoral cavity in its dorsal third. This region is essential for THR stability, but the degree of contact between the septum and standard THR implants has never been studied. We obtained CT scans of 50 arthrotic hip joints from patients requiring THR. Virtual stems (50 straight/wedge-shaped and 50 anatomic stems) were placed in CT images of the femora using a PC-based preoperative planning unit. The dimensions of the septum, degree and location of contact between the septum and implants were recorded. A septum of cortical density was seen in 49/50 CT scans. It was 11 (2.9) mm long (medial-lateral), 3.5 (0.7) mm wide and 32 (10) mm high (caudal-cranial, mean (SD)). 94/100 implanted virtual stems showed direct contact with the septum. 31 straight stems and 5 anatomical stems were supported by the septum along their dorsal side. The internal calcar septum can be consistently seen on CT scans of patients needing THR and it probably contributes to THR stability.

Cementless total hip replacement with subtrochanteric femoral shortening for severe developmental dysplasia of the hip.

INTRODUCTION: Total joint replacement in patients suffering from developmental dysplasia of the hip poses specific technical difficulties due to insufficient bone stock at the site of the original and secondary acetabulum and a narrow, cranially displaced proximal femur. MATERIALS AND METHODS: Twelve hips with severe congenital dislocation (4 Crowe type II, 5 type III, 3 type IV) were treated with cementless, porous structured total hip replacement. The cup was implanted at the anatomic height, a femoral segment was resected below the minor trochanter to reduce the femoral component in all cases. RESULTS: One femoral component was exchanged for a longer stem after 2 months due to insufficient fit and fill. After a mean follow-up of 5.1 years, there were no further revisions or radiographic signs of loosening. No cup was revised or loose radiographically. Harris hip score (mean) improved from 36 to 82 points, mean leg length discrepancy was reduced from 5.4 to 1.3 cm. CONCLUSION: The cementless technique described is useful in cases of severe congenital dislocation of the hip when the cup is implanted at the anatomic level, and implant reduction is not possible despite thorough soft-tissue release or not advisable because of excessive limb lengthening. A reconstruction of the original joint center and good mid-term results are demonstrated.

Shock wave application for chronic plantar fasciitis in running athletes. A prospective, randomized, placebo-controlled trial.

BACKGROUND: Recent articles have reported success with repeated low-energy shock wave application for treatment of chronic plantar fasciitis in runners. HYPOTHESIS: Shock wave treatment for chronic plantar fasciitis is safe and effective. STUDY DESIGN: Prospective, randomized, placebo-controlled trial. METHODS: Forty-five running athletes with intractable plantar heel pain for more than 12 months were enrolled; half were assigned to a treatment group that received three applications of 2100 impulses of low-energy shock waves, and half received sham treatment. Follow-up examinations were performed at 6 months and at 1 year by a blinded observer. RESULTS: After 6 months, self-assessment of pain on first walking in the morning was significantly reduced from an average of 6.9 to 2.1 points on a visual analog scale in the treatment group and from an average of 7.0 to 4.7 points in the sham group. The mean difference between groups was 2.6 points. After 12 months, there was a further reduction of pain in both groups, to an average 1.5 points in the treatment group, and to 4.4 points in the sham group. CONCLUSION: Three treatments with 2100 impulses of low-energy shock waves were a safe and effective method for treatment of chronic plantar fasciitis in long-distance runners.