Primary stability of total hip stems: does surgical technique matter?

BACKGROUND: With this preliminary study we hypothesized a modified implantation technique may lead to higher primary stability than the conventional one. METHODS: In the conventional technique we used a sharp spoon to open the femoral cavity. Subsequently the opening was extended by increasing sizes of a sensing device to approve the final size. Finally, a bone compactor of the corresponding size was inserted in the cavity preparing it for implantation while compressing the surrounding cancellous bone. After initial opening of the femoral canal with a sharp spoon, the modified implantation technique was characterized by direct use of increasing sizes of bone compactors. A standardized procedure was implemented for micromotion analysis using LVDT's. Each specimen was positioned in a servo-hydraulic testing machine following a standardized test regime. A total of 1500 load cycles with a maximum hip reaction force of 1000 N were applied on each sample in three series of 500 cycles. The force was applied as a cyclic sinusoidal with a frequency of 1 Hz and a load ratio of R = 0.1. RESULTS: No significant differences of micromotion between implant and surrounding bone stock could be detected regarding conventional vs. modified implantation technique. However, independent of the surgical technique used, significant differences were observed for the operated side, i.e. backhand driving of right-handed surgeon resulted in higher interfacial micromotions at the left side. CONCLUSION: The results did not support our hypothesis. However, the correlation found between operated side and surgeon's backhand driving as a potential risk for reduced primary stability should encourage further investigations.

Length of stay after introduction of a new total knee arthroplasty (TKA)-results of a German retrospective database analysis.

BACKGROUND: Although total knee arthroplasty (TKA) procedures are increasing, patient satisfaction is still inferior compared to total hip arthroplasty. The ATTUNE® Knee System was designed to reduce pain and improve function, leading to greater patient satisfaction and decreased resource utilization in TKA. The objective of this study was to compare length of stay (LOS) of TKA with ATTUNE knee versus LCS® knee implants. METHODS: A retrospective chart review analysis in a German center was conducted between 2008 and 2016. All patients without prior ipsilateral knee operation, treated with a cemented LCS or ATTUNE knee were included. Endpoints captured included gender, age, availability of home support, prior contralateral TKA, ASA grade and LOS. Statistical analyses included chi-squared test for differences in patient demographics and Welch two-sample t-test for difference in LOS. RESULTS: Mean LOS in the ATTUNE Knee group (N=85) was 8.3 days (SD: 1.79) compared to 10.4 days (SD: 1.91) in the LCS knee group (N=85). No significant differences in gender, age, availability of home support, prior contralateral TKA, or ASA grade between both cohorts were observed. The 2.1 days reduction was statistically significant (P<0.001; 95%CI: 2.7-1.6). A sensitivity analysis outlined the impact of the study duration: even when assuming that 1.3 days reduction resulted from the observed national LOS decrease, the remaining 0.8 reduction in days LOS reduction was still significant (P<0.01). CONCLUSION: When comparing two cohorts with similar sociodemographic and medical factors, LOS of ATTUNE knee patients was 2.1 days shorter than patients treated with the LCS knee.

Morselized bone grafting in revision arthroplasty of the knee: a retrospective analysis of 34 reconstructions after 2-9 years.

BACKGROUND AND PURPOSE: Loosening of a total knee replacement may lead to loss of bone, requiring biological reconstruction at revision arthroplasty. Good results have been reported from revision arthroplasty of the hip using impaction bone grafting. We report our results of revision total knee arthroplasty using the same technique. PATIENTS AND METHODS: We retrospectively analyzed 30 patients (involving 34 knees) with a mean age of 63 (34-81) years who, between 1994 and 2002, underwent revision arthroplasty of the knee using hinge or rotational knee prostheses (Link) and impaction bone grafting. The average follow-up was 4 (2-9) years and included a questionnaire, a clinical examination, and standardized radiographs. RESULTS: 25 patients were satisfied with their results. 10 patients reported no impairment in their activities of daily living attributed to their operation and did not need any walking support. In 5 patients, there were no clear radiographic signs of incorporation of the graft but that did not compromise the outcome. 5 other patients had complications due to aseptic loosening of their prostheses with radiographic failure of the graft, leading to a periprosthetic fracture in 2 cases. INTERPRETATION: Our results with impaction bone grafting in knee revision arthroplasty appear to be similar to those obtained by the same technique in revision hip surgery.

[Parsonage-Turner Syndrome - Case Report]. / Das Parsonage-Turner-Syndrom.

Neuralgic amyotrophy of the shoulder (Parsonage-Turner syndrome) is a rare condition of unknown aetiology which manifests as acute neuropathy of the brachial plexus. Diagnosis is based on typical symptoms and physical examination. In addition, magnetic resonance imaging of the affected shoulder and the cervical spine is advisable, in order to distinguish this syndrome from other conditions with similar symptoms. There is no specific treatment for neuralgic amyotrophy, but in about 50 - 67% of cases complete recovery occurs within two to three years, depending on the severity of the symptoms when they first appear. In patients whose strength and function are not fully restored, neurological deficits may remain, especially if the same shoulder is affected by recurrent attacks.

Cobalt deposition in mineralized bone tissue after metal-on-metal hip resurfacing: Quantitative µ-X-ray-fluorescence analysis of implant material incorporation in periprosthetic tissue.

Most resurfacing systems are manufactured from cobalt-chromium alloys with metal-on-metal (MoM) bearing couples. Because the quantity of particulate metal and corrosion products which can be released into the periprosthetic milieu is greater in MoM bearings than in metal-on-polyethylene (MoP) bearings, it is hypothesized that the quantity and distribution of debris released by the MoM components induce a compositional change in the periprosthetic bone. To determine the validity of this claim, nondestructive µ-X-ray fluorescence analysis was carried out on undecalcified histological samples from 13 femoral heads which had undergone surface replacement. These samples were extracted from the patients after gradient time points due to required revision surgery. Samples from nonintervened femoral heads as well as from a MoP resurfaced implant served as controls. Light microscopy and µ-X-ray fluorescence analyses revealed that cobalt debris was found not only in the soft tissue around the prosthesis and the bone marrow, but also in the mineralized bone tissue. Mineralized bone exposed to surface replacements showed significant increases in cobalt concentrations in comparison with control specimens without an implant. A maximum cobalt concentration in mineralized hard tissue of up to 380 ppm was detected as early as 2 years after implantation. Values of this magnitude are not found in implants with a MoP surface bearing until a lifetime of more than 20 years. This study demonstrates that hip resurfacing implants with MoM bearings present a potential long-term health risk due to rapid cobalt ion accumulation in periprosthetic hard tissue. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1855-1862, 2017.

Proliferation of the synovial lining cell layer in suggested metal hypersensitivity.

Synovial tissues in joints with prostheses display characteristic morphological changes in cases with aseptic failure, particularly macrophage infiltration. Since proliferation of the synovial lining cell layer represents a feature characteristic of autoimmune joint diseases, the possibility of morphological changes of the synovial lining cell layer in periprosthetic tissues was investigated. Synovial biopsies from five groups of morphologically well-defined lesions (osteoarthritis, rheumatoid arthritis, aseptic loosened metal-on-polyethylene and metal-on-metal arthroplasty and suggested metal hypersensitivity) were compared using a conventional staining method and immunohistochemistry. The synovial lining cell layer was substantially enlarged in both rheumatoid arthritis and cases suggestive of metal hypersensitivity. Macrophage infiltrates were apparent in rheumatoid arthritis and all specimens from retrieved hip arthroplasties. Although both synovial and subsynovial macrophages were positive for CD163 (indicating synovial M2 macrophages), the remaining fibroblast-like synoviocytes and scattered stromal fibroblasts showed a positive reaction with the D2-40 antibody (indicating fibroblast-like synoviocytes). Furthermore, in contrast to CD163-positive macrophages, the enlarged D2-40-positive fibroblast-like synoviocytes displayed cytoplasmatic tubular projections. Proliferation of the periprosthetic synovial lining cell layer occurred in cases with unexplained groin pain following metal-on-metal hip resurfacing arthroplasty, suggestive of hypersensitivity. Despite some important study limitations, the present observation adds to the evidence that metal hypersensitivity shares characteristic morphological features with autoimmune diseases of the joints.

Component exchange in treatment of periprosthetic femoral fractures.

A retrospective analysis of 893 consecutive periprosthetic femoral fractures treated between 1976 and 2001 shows that component exchange with reimplantation of a cemented long-stem implant can be considered a reliable method of treatment with good functional results and low rates of complications (10%) and revision (7.5%). The possibility of increasing the degree of weight bearing postoperatively at an early stage or even immediate full weight bearing (25%) greatly facilitates mobilization of the mostly elderly and fragile patients. Evaluation according to the Harris Hip Score of the operation and rehabilitation results of a representative sample of 120 patients shows an average value of 85 after a mean period of 6.4 years. The patients' own rating is correspondingly high. In the authors' view, stem exchange is currently the method of choice in the majority of cases because of the rather high rate of stem loosening (77%) at the time of operation, the age-related frequently poor quality or loss of bone substance, and the possibility that the implant material may be damaged. The fact that more than one third of the fractures occurred without significant trauma underlines the importance of this injury as a possible sign of previously unrecognized osteolysis and weakening of the bone as a result of loosening of the prosthesis stem.

Surgery of skeletal metastases.

During a period of 5 years, 74 female and 27 male patients with an average age of 63.3 years underwent a total of 117 operations for the management of impending ( n=41) or already existing ( n=76) pathologic fractures due to osseous metastases. The average stay in hospital was 17.8 days, and the average postoperative survival 15.8 months. The patients whose limbs were stabilized as a preventive measure were discharged 1.5 days earlier and survived surgery 5.9 months longer than the patients with pathologic fractures. The large percentage of female patients is due to the predominant role of mammary cancer (50%) and the comparatively long survival of patients after a primary diagnosis of this type of carcinoma. The other diagnoses involved were (in order of frequency): bronchial carcinoma (11%), hypernephroma (8%) and non-Hodgkin's lymphoma (8%). The metastases were mainly located at the proximal end or shaft of the femur (59.8%) and in the humerus (18.8%) so that in the majority of cases it was possible to implant weight-bearing prostheses or at least achieve enough stability to allow non-weight-bearing physiotherapy and thus early remobilization. The rate of systemic complications (excluding fatalities) was 14.5%. Local complications in the operated area occurred in 24.8% of cases. As a result, revision surgery was necessary in 10 cases (8.5%), and the fatality rate in hospital (6 weeks) was 7.9%. In view of the advanced stage of the disease in most of the patients, some of them with polypathia, we see these results as a basis for the generous indication for preventive stabilization of osseous metastases. Except in some cases, the primary intention of this therapy is not to cure the disease or prolong life but to improve the quality of life remaining for these patients while keeping their stay in hospital as short as possible and the rate of complications at an acceptable level.