The resisted torsional stress test in diagnosis of femoral stem loosening in uncemented total hip arthroplasty - first description and retrospective study.

INTRODUCTION: Aseptic femoral stem loosening is among the most common causes for revision in total hip arthroplasty (THA). We describe a simple clinical test that triggers pain in the proximal femur in patients with a loose stem. A previously described passive rotation test was associated with a poor sensitivity. The resisted torsional stress test (RTST) was used for several years in our hospital, and this is the first description of its reliability. METHODS: We retrospectively reviewed our database of uncemented stem revisions. Preoperative clinical reports were searched for data on the RTST. A positive RTST was defined as sharp pain felt at the stem level with active internal rotation against a passive external rotation impulse in 90° hip flexion. The definition of stem fixation (fixed vs. loose) was made by readout of the surgery reports. RESULTS: The RTST was reported in 83 cases and was positive in 32 of the 43 stems, which were found loose intraoperatively and in 9 of the 40 stems, which were well integrated. This leads to an accuracy of classification of 79.5%. The sensitivity was 80% and the specificity was 79.1%. PPV and NPV were 78% and 81%, respectively. CONCLUSION: The RTST provides a helpful tool in the clinical assessment of femoral stem fixation in THA with good accuracy and should be included in standard follow-up examinations and in the assessment of painful THAs.

Skin crease 'bikini' incision for the direct anterior approach in total hip arthroplasty: a two- to four-year comparative study in 964 patients.

Aims: The classical longitudinal incision used for the direct anterior approach (DAA) to the hip does not follow the tension lines of the skin and can lead to impaired wound healing and poor cosmesis. The purpose of this retrospective study was to determine the satisfaction with the scar, and functional and radiographic outcomes comparing the classic longitudinal incision with a modified skin crease 'bikini' when the DAA is used for total hip arthroplasty (THA). Patients and Methods: A total of 964 patients (51% female; 59% longitudinal, 41% 'bikini') completed a follow-up questionnaire between two and four years postoperatively, including the Oxford Hip Score (OHS), the University of North Carolina '4P' scar scale (UNC4P) and two items for assessing the aesthetic appearance of the scar and symptoms of numbness. The positioning of the components, rates of heterotopic ossification (HO) and rates of revision were assessed. Results: The mean OHS was similar in both groups (p = 0.41). The mean UNC4P total score was slightly better (p = 0.01) and the proportion of patients who were very satisfied with the cosmetic aspects of the scar was higher in the 'bikini' group (p < 0.001). The proportion of patients reporting numbness in the scar was higher in the longitudinal group (14.5% vs 7.5%, respectively, p < 0.001). The abduction angle of the acetabular component, the position of the stem and rates of HO did not differ between the groups. There were no differences in the revision rates of both groups, being 2.3% in the longitudinal and 1.5% in the 'bikini' group (p = 0.911). Conclusion: We found that a short oblique 'bikini' skin crease incision is safe when used for the DAA at THA, without compromising the positioning of the components or increasing the rate of lateral femoral cutaneous nerve dysaesthesia. Although it leads to a superior scar satisfaction, as it is less extensile, it should be used after having gained experience with the classic longitudinal incision. Cite this article: Bone Joint J 2018;100-B:853-61.

Full-field measurement of micromotion around a cementless femoral stem using micro-CT imaging and radiopaque markers.

A good primary stability of cementless femoral stems is essential for the long-term success of total hip arthroplasty. Experimental measurement of implant micromotion with linear variable differential transformers is commonly used to assess implant primary stability in pre-clinical testing. But these measurements are often limited to a few distinct points at the interface. New techniques based on micro-computed tomography (micro-CT) have recently been introduced, such as Digital Volume Correlation (DVC) or markers-based approaches. DVC is however limited to measurement around non-metallic implants due to metal-induced imaging artifacts, and markers-based techniques are confined to a small portion of the implant. In this paper, we present a technique based on micro-CT imaging and radiopaque markers to provide the first full-field micromotion measurement at the entire bone-implant interface of a cementless femoral stem implanted in a cadaveric femur. Micromotion was measured during compression and torsion. Over 300 simultaneous measurement points were obtained. Micromotion amplitude ranged from 0 to 24µm in compression and from 0 to 49µm in torsion. Peak micromotion was distal in compression and proximal in torsion. The technique bias was 5.1µm and its repeatability standard deviation was 4µm. The method was thus highly reliable and compared well with results obtained with linear variable differential transformers (LVDTs) reported in the literature. These results indicate that this micro-CT based technique is perfectly relevant to observe local variations in primary stability around metallic implants. Possible applications include pre-clinical testing of implants and validation of patient-specific models for pre-operative planning.

Adverse tissue reaction to corrosion at the neck-stem junction after modular primary total hip arthroplasty.

Complications related to the neck-stem junction of modular stems used for total hip arthroplasty (THA) are generating increasing concern. A 74-year-old male had increasing pain and a cutaneous reaction around the scar 1 year after THA with a modular neck-stem. Imaging revealed osteolysis of the calcar and a pseudo-tumour adjacent to the neck-stem junction. Serum cobalt levels were elevated. Revision surgery to exchange the stem and liner and to resect the pseudo-tumour was performed. Analysis of the stem by scanning electron microscopy and by energy dispersive X-ray and white light interferometry showed fretting corrosion at the neck-stem junction contrasting with minimal changes at the head-neck junction. Thus, despite dry assembly of the neck and stem on the back table at primary THA, full neck-stem contact was not achieved, and the resulting micromotion at the interface led to fretting corrosion. This case highlights the mechanism of fretting corrosion at the neck-stem interface responsible for adverse local tissue reactions. Clinical and radiological follow-up is mandatory in patients with dual-modular stems.

Radiation therapy in the treatment of desmoid tumours reduces surgical indications.

BACKGROUND: While several modalities have been proposed for the treatment of desmoid tumour/aggressive fibromatosis, high local recurrence rates have been reported. We present a retrospective study of including patients treated with radiation therapy, some of them in combination with surgical resection. PATIENTS AND METHODS: Thirty-four consecutive patients were included (mean age 40+/-16 years, 9 male). Complete follow-up was available in 31 patients (51+/-36 months). Seventeen patients (50%) were treated with radiation therapy alone, 17 patients with radiation therapy and surgery. Radiation therapy (external beam) was applied in most cases to a total dose of 50.4 Gy in 28 fractions. The lesion was located in the upper extremity in 11 patients, in the lower extremity in 14 cases and on the trunk in 9 cases. RESULTS: Overall recurrence/progression free survival was 88.5% at 5 years and 77.5% at 10 years. Recurrence free survival of the subset of patients undergoing combined treatment with radiation therapy and surgical resection was 83.6% at 5 years and 10 years. In patients who did not receive surgery but only radiation therapy, MRI showed a complete response in 20%, a partial response in 20%, and stable disease in 53% of cases. In this subset, two-third of patient had a metabolic response to radiotherapy (i.e. decrease uptake on the thallium-210 scan after radiotherapy compared to pre-therapy levels). CONCLUSION: Low recurrence rates can be achieved with the use of radiation therapy alone in selected cases. Patients with a metabolic response (decrease) to radiotherapy may be treated with a non-surgical approach. Surgery might be considered in patients with a poor metabolic response to radiotherapy.

Limb salvage surgery in combination with brachytherapy and external beam radiation for high-grade soft tissue sarcomas.

While combined treatment of high-grade soft tissue sarcoma with resection and radiotherapy has become an accepted standard, outlines of treatment algorithms remain a matter of debate. Our institutional practice foresees wide surgical resection with adjuvant brachytherapy and external beam radiation. It was the purpose of this study to determine long-term outcome, prognostic factors for local and systemic recurrence and morbidity in patients with high-grade soft tissue sarcomas of the extremities, who were subjected to this regimen. One hundred and twelve patients met the inclusion criteria (56 male, 56 female; median age, 50 years). Median follow-up was 75 months (min. 11 months). Overall survival rate was 77.5% and 71.1% at 5 and 7 years, respectively. Disease-free survival rate was 63.3% and 58.4% at 5 and 10 years, respectively. Local control was achieved in 91.5% and 87.0% at 5 and 10 years, respectively. Wide surgical margins were associated with a significantly better local control rate compared to marginal or intralesional margins. Tumor size did correlate with systemic but not local recurrence. Tumor site and histotype did not appear to have an impact on outcome. Chemotherapy did not show to have an impact on local or systemic control. Fourteen patients (12.5%) had local complications attributed to radiotherapy. Eleven patients developed wound-healing problems, which needed further surgery. Using our treatment algorithm for high-grade soft tissue sarcoma of the extremities, good local and systemic control can be achieved with a low complication rate.

Soft tissue sarcomas of the popliteal fossa: outcome and risk factors.

BACKGROUND: Limb salvage surgery of popliteal soft tissue sarcomas may be hampered due to the incomplete anatomical containment of this region and the vicinity of neurovascular structures. The scope of this study was to determine outcome and to define risk factors. PATIENTS AND METHODS: 27 patients (53.3+/-15.8 y; 16/27 male) with popliteal soft tissue sarcomas were assessed. Mean follow-up was 40.9+/-33.8 months (48.5+/-36.7 months in surviving patients). 9/27 patients were included after prior treatment elsewhere (5 after intralesional resections and 4 local recurrences). The lesions were staged IB in 8/27 patients, IIB in 17/27 and III in 2/27. Immediate amputations were performed in 7/27 patients. 15/27 patients were subjected to radiation therapy (preoperative in 6/15 cases), 8/27 patients received chemotherapy (5/8 preoperatively). RESULTS: Overall survival and disease-free survival at 5 y was 63.0% and 59.5%. Local recurrence occurred in 2 patients. 8/27 patients developed metastatic disease after 28.9+/-9.8 months. Survival (p=0.397) and disease-free survival (p=0.113) did not differ in patients after amputations vs limb salvage. Application of radiation therapy was associated with a better survival (p=0.003). Complications related to the surgical intervention were recorded in 2/27 patients, complications related to radiation therapy occurred in 6/15 patients. DISCUSSION: Despite being extra-compartmental, popliteal sarcomas can be treated with a high rate of limb salvage while equal safety compared to amputations is maintained. Irradiation improved survival in our patient population. In cases with involvement of neurovascular structures, preoperative down-staging with radio or chemo-therapy may prevent amputation.

Induction of apoptotic cell death and prevention of tumor growth by ceramide analogues in metastatic human colon cancer.

Dysfunction in the physiological pathways of programmed cell death may promote proliferation of malignant cells, and correction of such defects may selectively induce apoptosis in cancer cells. We measured the levels of ceramide, a candidate lipid mediator of apoptosis, in human metastatic colorectal cancer and tested in vitro and in vivo effects of various ceramide analogues in inducing apoptosis in metastatic colon cancer. Human colon cancer showed a > 50% decrease in the cellular content of ceramide when compared with normal colon mucosa. Application of ceramide analogues and ceramidase inhibitors induced rapid cell death through activation of various proapoptotic molecules, such as caspases and release of cytochrome c. Ceramidase inhibition increases the ceramide content of tumor cells, resulting in maximum activation of the apoptotic cascade. Normal liver cells were completely resistant to inhibitors of ceramidases. Treatment of nude mice with B13, the most potent ceramidase inhibitor, completely prevented tumor growth using two different aggressive human colon cancer cell lines metastatic to the liver. Therefore, B13 and related analogues of ceramide and inhibitors of ceramidases offer a promising therapeutic strategy with selective toxicity toward malignant but not normal cells. These studies also suggest that the ceramide content in cancer cells might be involved in the pathogenesis of tumor growth in vitro and in vivo.

Mechanisms of ischemic injury are different in the steatotic and normal rat liver.

Hepatic steatosis is associated with significant morbidity and mortality after liver resection and transplantation. Although apoptosis is a key mechanism of reperfusion injury in the normal liver, the pathway leading to cell death in steatotic hepatocytes is unknown. A model of hepatic ischemia and reperfusion injury in fatty and lean Zucker rats was used. Fatty animals had increased aspartate aminotransferase (AST) release and decreased survival after 60 minutes of ischemia compared with lean animals. Apoptosis was the predominant form of cell death in the lean rats (82%), whereas necrosis was minimal. In contrast, fatty animals developed only moderate amounts of apoptosis but showed massive necrosis (73%) after 24 hours of reperfusion. Intracellular mediators of apoptosis, such as caspase 8, caspase 3, and cytochrome c, were significantly lower in the steatotic than in the lean liver indicating dysfunction in activation of the apoptotic pathway. The high percentage of necrosis in the steatotic rats was associated with renal acute tubular necrosis after 24 hours of reperfusion in the fatty, but not in lean rats. Caspase inhibition significantly decreased reperfusion injury in lean animals, but was ineffective in fatty animals. The results indicate that the increased susceptibility of fatty livers to reperfusion injury is associated with a change from an apoptotic form of cell death to necrosis. We conclude that new therapeutic strategies are necessary in the fatty liver.