No abstract

Careful preoperative planning was useful for accurate size choice of the Mayo prosthesis. Factors such as the height of osteotomy and the distance from the medial margin of the stem to the medial margin of the medial femoral cortex in relation to the position of the Mayo stem should be taken into account in order to restore ideal offset and leg length.

Total knee arthroplasty is successful in the treatment of degenerative, arthritic or injured joints. But the most important long term complication seems to be aseptic loosening. An inflammatory process at the bone/cement or bone/prosthesis interface leads to a severe osteolysis. Although early diagnosis is very important the standard techniques often fail. [(18)F]Fluoride ion positron emission tomography (F-PET) is an appropriate tracer paired with a modern method for the evaluation of increased bone metabolism at the bone/prosthesis interface. In this preliminary study we describe for the first time the value of F-PET in the early diagnosis of aseptic loosening. We studied 14 painful knee arthoplasties. In 6 cases the definite diagnosis was determined by surgical procedure, for 8 cases a long clinical follow-up of the least 6 months after the onset of symptoms led to the diagnosis. The F-PET scans were obtained by with an ECAT EXACT HR+ scanner with and without attenuation correction in the two-and three-dimensional mode. An intermediate or high uptake along the bone/prosthesis or bone/cement interface including either the tibial stem or the half of the femoral component was suspected to be aseptic loose. The result were compared with plain radiographs. We found a sensitivity of 100%, a specificity of 56% and an accuracy of 71%. No false negative results were detected, in 4 patients one component as false positive. The sensitivity, specificity and accuracy for the plain radiograph of the same patients were 43%, 86% and 64%, respectively. In conclusion PET seems to be a promising new method in the early diagnosis of painful TKA because of its excellent spatial solution. In combination with the bone seeking tracer [(18) F]fluoride, PET allows the detection of aseptic loosening and the differentiation to the simple synovitis. Our preliminary results suggest that F-PET could be a useful tool although we examined a small group of patients.

There is still controversy as to whether minimally invasive total hip arthroplasty enhances the postoperative outcome. The aim of this study was to compare the outcome of patients who underwent total hip replacement through an anterolateral minimally invasive (MIS) or a conventional lateral approach (CON). We performed a randomized, prospective study of 75 patients with primary hip arthritis, who underwent hip replacement through the MIS (n=36) or CON (n=39) approach. The Western Ontario and McMaster Universities Osteoarthritis Index and Harris Hip score (HHS) were evaluated at frequent intervals during the early postoperative follow-up period and then after 3.5 years. Pain sensations were recorded. Serological and radiological analyses were performed. In the MIS group the patients had smaller skin incisions and there was a significantly lower rate of patients with a positive Trendelenburg sign after six weeks postoperatively. After six weeks the HHS was 6.85 points higher in the MIS group (P=0.045). But calculating the mean difference between the baseline and the six weeks HHS we evaluated no significant differences. Blood loss was greater and the duration of surgery was longer in the MIS group. The other parameters, especially after the twelfth week, did not differ significantly. Radiographs showed the inclination of the acetabular component to be significantly higher in the MIS group, but on average it was within the same permitted tolerance range as in the CON group. Both approaches are adequate for hip replacement. Given the data, there appears to be no significant long term advantage to the MIS approach, as described in this study.

ObjectivePortal assisted minimally invasive total hip arthroplasty without dislocation of the femoral head with preservation of the hip capsule and the external rotators in the lateral decubitus position for rapid recovery with the option of expandability to a mini posterior or classic posterolateral approach at any time.IndicationsPrimary and secondary arthritis of the hip, femoral head necrosis, femoral neck fracture.ContraindicationsSevere anatomical disorders of the proximal femur, congenital high hip dysplasia, implanted hardware in the trochanteric region, local and systemic infections.Surgical techniqueLateral decubitus position, skin incision of 6–10 cm from the tip of the greater trochanter in line with the femoral axis, spread gluteus maximus, using the interval between the piriformis tendon posterior and gluteus minimus/medius muscle anterior, incision of the capsule, remove bone of the lateral neck and head, intramedullary reaming and broaching of the femur, osteotomy of the femoral neck with the femoral broach left in situ, remove the femoral head, preparation of the acetabulum using a cannula posterior of the femur, cup impaction and implantation of the inlay, trial modular neck and head, reposition, test of leg length, impingement and stability, x‑ray, implantation of the definitive components, closure of the capsule, standard wound closure.Postoperative managementFull weight bearing as possible, no restrictions of postoperative movement.ResultsThe first 150 patients were operated from January 2016 to July 2017 without leg length discrepancy more than 5 mm; one transfusion was needed. There were two subluxations, one wound dehiscence and one femoral diaphyseal fracture 4 weeks after surgery. There was no radiological loosening of the components after a mean of 16 months.