Agreement in component size between preoperative measurement, navigation and final implant in total knee replacement.

BACKGROUND: One of the possible causes of dissatisfaction reported by many patients after total knee replacement (TKR) is the lack of agreement between component size and bone structure. To avoid this complication and facilitate the procedure, preoperative planning with digitized templates is recommended. Surgical navigation indicates the best position and the most adequate size of arthroplasty and may therefore replace preoperative radiographic measurement. The objective of the study was to check agreement between the sizes of TKR components measured before surgery with digitized templates, the size recommended by the navigation and sizes actually implanted. METHODS: In 103 patients scheduled for TKR, preoperative full-limb radiography was performed to measure the mechanical and anatomical axes of the limb, femur and tibia. The most adequate size of the femoral and tibial components was planned by superimposing digitized templates. The size recommended in navigation and the size of the finally implanted components were also recorded. RESULTS: A high level of agreement was found between the sizes of femoral and tibial components measured by X-rays and in navigation (0.750 and 0.772, respectively) (intraclass correlation and Cronbach's alpha). Agreement between the sizes recommended by X-rays and navigation and those finally implanted was 0.886 for the femur and 0.891 for the tibia. Agreement levels were not different in cases with prior deformities of limb axis. CONCLUSIONS: The high level of agreement found in component sizes between radiographic measurement with digitized templates and navigation suggests that preoperative X-ray measurement is not needed when navigation is used for placement of implants during TKR. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: Computer-assisted surgery may avoid preoperative measurement with templates in TKR.

In-hospital care, complications, and 4-month mortality following a hip or proximal femur fracture: the Spanish registry of osteoporotic femur fractures prospective cohort study.

We have characterised 997 hip fracture patients from a representative 45 Spanish hospitals, and followed them up prospectively for up to 4 months. Despite suboptimal surgical delays (average 59.1 hours), in-hospital mortality was lower than in Northern European cohorts. The secondary fracture prevention gap is unacceptably high at 85%. PURPOSE: To characterise inpatient care, complications, and 4-month mortality following a hip or proximal femur fracture in Spain. METHODS: Design: prospective cohort study. Consecutive sample of patients ≥ 50 years old admitted in a representative 45 hospitals for a hip or proximal femur fragility fracture, from June 2014 to June 2016 and followed up for 4 months post-fracture. Patient characteristics, site of fracture, in-patient care (including secondary fracture prevention) and complications, and 4-month mortality are described. RESULTS: A total of 997 subjects (765 women) of mean (standard deviation) age 83.6 (8.4) years were included. Previous history of fracture/s (36.9%) and falls (43%) were common, and 10-year FRAX-estimated major and hip fracture risks were 15.2% (9.0%) and 8.5% (7.6%) respectively. Inter-trochanteric (44.6%) and displaced intra-capsular (28.0%) were the most common fracture sites, and fixation with short intramedullary nail (38.6%) with spinal anaesthesia (75.5%) the most common procedures. Surgery and rehabilitation were initiated within a mean 59.1 (56.7) and 61.9 (55.1) hours respectively, and average length of stay was 11.5 (9.3) days. Antithrombotic and antibiotic prophylaxis were given to 99.8% and 98.2% respectively, whilst only 12.4% received secondary fracture prevention at discharge. Common complications included delirium (36.1 %) and kidney failure (14.1%), with in-hospital and 4-month mortality of 2.1% and 11% respectively. CONCLUSIONS: Despite suboptimal surgical delay, post-hip fracture mortality is low in Spanish hospitals. The secondary fracture prevention gap is unacceptably high at > 85%, in spite of virtually universal anti-thrombotic and antibiotic prophylaxis.

Computed tomography is not necessary to assess rotation of the femoral component in navigation-assisted total knee replacement.

Objective To demonstrate that postoperative computed tomography (CT) is not needed if navigation is used to determine the rotational position of the femoral component during total knee replacement (TKR). Methods Preoperative CT, navigational, and postoperative CT data of 70 TKR procedures were analysed. The correlation between the rotational angulation of the femur measured by CT and that measured by perioperative navigation was examined. The correlation between the femoral component rotation determined by navigation and that determined by CT was also assessed. Results The mean femoral rotation determined by navigation was 2.64° ± 4.34°, while that shown by CT was 6.43° ± 1.65°. Postoperative rotation of the femoral component shown by CT was 3.09° ± 2.71°, which was closely correlated with the angle obtained through the intraoperative transepicondylar axis by navigation (Pearson's R = 0.930). Conclusions Navigation can be used to collect the preoperative, intraoperative, and postoperative data and final position of the TKR. The rotation of the femoral component can be determined using navigation without the need for CT.

Treatment of periprosthetic femoral fractures with modular stems.

PURPOSE: The purpose of this study was to analyse the efficacy of modular femoral stems for the treatment of certain post-operative periprosthetic fractures in patients with hip arthroplasty. METHODS: Of a total series of 61 modular revision stems, 17 were used to address periprosthetic femoral fractures and 12 of these are the object of this study. The average follow-up was 3.7 years (range 1-14 years). The evaluations were performed at three and six months, and then annually using the HHS score and radiographic studies for the assessment of loosening, subsidence and bone integration of the stem. RESULTS: Seven cases had type B2 fractures and five type B3 ones. All patients walked freely, eight of them using canes. HHS improved to a post-operative mean of 78 (range 72-83). Radiographically, fracture healing was observed at three months in nine cases. In six cases stem subsidence of a mean of 3.9 mm (range 2-12 mm) was observed, which stabilized a year following implantation and did not need revision surgery. In two cases a subsequent dislocation (at three and seven months after surgery) occurred, which were treated with constrained acetabular systems. In nine cases hypotrophy of the cortex in the diaphyseal area was noted, which did not alter the patients' clinical course. CONCLUSION: Modular femoral stems are an acceptable treatment in type B2 and B3 periprosthetic fractures.

Influence of clinical and radiological variables on the extent and distribution of periprosthetic osteolysis in total hip arthroplasty with a hydroxyapatite-coated multiple-hole acetabular component: a magnetic resonance imaging study.

Polyethylene wear-induced osteolysis constitutes the most severe long-term complication of total hip arthroplasties (THA). Our aim was to assess through MRI the severity and growth pattern of osteolysis, as well as the influence clinical-radiographic variables exert. We analyzed 75 THA with an average evolution time of 13.67years. The implant was a titanium alloy, non-cemented, multiple-hole model with hydroxyapatite coating. Osteolysis was found with a peripheral pattern in 48 and a central pattern in 6; in 52 cases it was continuous, and in 4, isolated. Out of 118 screws, 20 exhibited lysis. There was a proportional correlation between osteolysis severity and wear rate with age, physical activity and acetabular abduction, as well as an association between said variables and peripheral and continuous patterns.