Limb alignment changes with knee flexion: A study based on CAS data.

BACKGROUND: Recent evidence has questioned the value of standing limb alignment for predicting the adduction moment and forces exerted on healthy and prosthetic knees. The purpose of this study was to assess the lower limb alignment of OA knee patients at various knee flexion angles. The main hypothesis was that lower limb alignment measured throughout knee flexion does not significantly differ between patients displaying different extension alignment (neutral, varus or valgus). METHODS: 206 arthritic knee patients undergoing computer-assisted total (CAS) knee prosthesis were included. Frontal limb alignment was assessed in a systematic manner by CAS at three knee positions: extension, 90 degrees of flexion and maximal flexion. The HKA angle at each knee position and the change in HKA angle between two knee positions (delta value) were reported and compared. RESULTS: A large proportion of OA patients had significant variation in their lower limb alignment (32% with Δ HKA > 5°). The extended limb deformity tended to reduce with knee flexion: mean of 5° and 6° deformity reduction for varus and valgus patients, 40% and 66% of varus and valgus patients progressed to neutral alignment with 90° knee flexion. Forty percent of neutral extended lower limb did not maintain their neutral alignment but rather progressed to either varus or valgus at 90° knee flexion. CONCLUSIONS: Limb alignment in extension is a poor predictor of limb alignment in flexion in OA patients. Only considering the traditional frontal alignment of an extended lower limb for planning knee arthroplasty or osteotomy is likely insufficient.

Comparison of a Minimally Invasive Tissue-Sparing Posterior Superior (TSPS) Approach and the Standard Posterior Approach for Hip Replacement.

Purpose: The purpose of this study is to compare the functional and clinical outcomes, blood loss, complication rate, and hospital length of stay (LOS) of total hip replacement (THR) using a minimally invasive tissue-sparing posterior superior (TSPS) approach and the standard posterior approach. Materials and Methods: This retrospective, observational, double-centered study included 38 patients undergoing hip replacement. The patents were divided into two groups: control group (19 patients), who underwent surgery with the standard posterior approach, and treatment group (19 patients), who received the same type of implant with ceramic-on-ceramic bearing via the TSPS approach. Hemoglobin level was assessed preoperatively, on first and second postoperative days, and on discharge day. Harris hip score and Western Ontario and McMaster Universities Arthritis Index were used to measure the clinical and functional outcomes. Hospital LOS and incidence of early and late complications were assessed in both groups. Postoperative anteroposterior pelvis X-ray was performed to assess the correct positioning of implants. Results: Better early clinical outcomes (p = 0.0155), lesser blood loss (p < 0.0001), and reduced hospital LOS (p < 0.0001) were observed in the TSPS group than in the control group. No major adverse effects occurred in both groups, and a satisfactory implant orientation was achieved in all patients. Conclusions: The TSPS approach is a reliable minimally invasive procedure for THR as it allows an accurate orientation of the components and provides better early postoperative functional outcomes, faster recovery, significantly lower blood loss, and shorter hospital LOS than the standard posterior approach. However, further research is needed to confirm the promising results and cost-effectiveness of the TSPS approach in larger cohorts with a longer follow-up period.

Giant hemorrhagic trochanteric bursitis mimicking a high-grade soft tissue sarcoma: report of two cases.

BACKGROUND: The giant haemorrhagic bursitis of the hip joint is a rare clinical condition that requires evidence-based guidelines for adequate diagnosis and management. Usually, this pathology requires conservative treatment; however, when abnormal size or clinical symptoms of compression of the surrounding noble structures are reported, an accurate differential diagnosis is required, in order to exclude other malignant conditions that can be included into differential diagnosis, and a surgical approach should be considered. The purpose of this work is to provide an appropriate description of the diagnostic and therapeutic path, providing an accurate analysis of the possible differential diagnoses. METHODS: We report 2 cases of symptomatic haemorrhagic bursitis of the hip joint, confirmed by histological investigation. In both cases, the patients complained a peripheral nerve deficit of a single limb: one patient presented paresthesia of lateral femoral cutaneous nerve while the second peripheral edema due to compression of the proximal venous and lymphatic circulation. RESULTS: Both cases were successfully managed by complete surgical excision of the mass, with no  recurrence. There were no major complications, but in first case the nerve deficit was permanent. CONCLUSIONS: Giant hemorrhagic trochanteric bursitis is a rare condition, but it should be included in the differential diagnosis of soft tissue masses arising from the hip joint. Due to the rarity of this entity, a cautious exclusion process of all plausible differential diagnosis must be undertaken, in order to not miss the possibility of soft-tissue tumors, primarily malignant high-grade sarcomas.

Reduced-dose computed tomography is the most accurate method to measure ceramic hip resurfacing cup version.

BACKGROUND: A precise assessment of cup version after hip resurfacing is generally requested, especially in clinical trials or in case of complications. AIMS: To identify which diagnostic imaging modality, between AP pelvis X-rays, the AP Pelvis CT Scout image and reduced-dose axial CT scan, is the most precise to assess cup version of an all-ceramic hip resurfacing implant in a first-in-human clinical trial. METHODS: We retrospectively assessed the cup version of the first 20 patients who underwent an experimental all-ceramic hip resurfacing on AP pelvis X-rays (0.8 mSv of radiation), AP pelvis CT scout images (0.016 mSv) and axial CT slices performed using a reduced dose protocol (0.3 mSv). The intra-observer and inter-observer reliabilities were calculated. RESULTS: Reduced dose Pelvis CT scan was the most precise imaging modality to detect cup version (Pearson Correlation Coefficient, PCC = 0.98, p < 0.001). The AP Pelvis CT Scout image was found to be sufficient to measure cup version within an acceptable margin of tolerance (mean difference ±â€¯4.7° from pelvis CT scan) and highly correlated to axial pelvis CT scan measurements (PCC 0.97, p < 0.001). Analysis of cup version from AP X-rays poorly correlated with measurements from Pelvis CT (PCC 0.59, p = 0.006). CONCLUSIONS: Due to lower radiation exposure and highest accuracy, reduced dose CT is a valid modality to measure acetabular cup version after ceramic hip resurfacing. Plain X-rays are not accurate nor precise to measure version, whereas high agreement of measurements between AP Pelvis CT Scout and axial pelvis CT scan was found.