We report the results of 62 hips in 62 patients
(17 males, 45 females) with mean age of 62.4 years (37 to 81), who underwent
revision of the acetabular component of a total hip replacement
due to aseptic loosening between May 2003 and November 2007. All
hips had a Paprosky type IIIa acetabular defect. Acetabular revision
was undertaken using a Procotyl E cementless oblong implant with
modular side plates and a hook combined with impaction allografting. At a mean follow-up of 60.5 months (36 to 94) with no patients
lost to follow-up and one died due to unrelated illness, the complication
rate was 38.7%. Complications included aseptic loosening (19 hips),
deep infection (3 hips), broken hook and side plate (one hip) and
a femoral nerve palsy (one hip). Further revision of the acetabular component
was required in 18 hips (29.0%) and a further four hips (6.4%) are
currently loose and awaiting revision. We observed unacceptably high rates of complication and failure
in our group of patients and cannot recommend this implant or technique.
Total hip arthroplasty is nowadays a common treatment for a large number of pathological cases regarding the hip joint and is considered as the most successful orthopedic operation. With the mean age of patients constantly decreasing and the more intense way of life, the need for versatile implant designs has arisen. Currently modular hip implant systems are used extensively in order to compensate for difficult occasions, where offset and version correction are required. In addition to this femoral heads of bigger diameter have been introduced to deal with issues such as dislocation and impingement, although their influence on the mechanical behavior on the bone – implant assembly is not widely documented. Towards this direction a finite element model was generated. Computed tomographies of a cadaveric femur were used as raw data and processed, a Profemur-E system with variable heads was digitized, thus leading to a complete assembly consisting of the femur, the stem, the necks and the femoral heads in the commercial CAD software Solidworks. For typical loading scenarios – the stance phase of the gait cycle – the finite element analysis was performed in ANSYS Workbench. The results showed that the implementation of BFH and the neck version produced an increase in strains and stresses with respect to a normal head of 28mm and a straight neck in areas of clinical interest such as the calcar, the greater trochanter area and the stem tip region, considered responsible for thigh pain.
Total Hip Arthroplasty (THA) is one of the most important procedures in the fields of Reconstructive Orthopaedics. This study aims to present the preliminary results of the clinical and radiological evaluation of patients who have undergone THA with metal bearings, modular necks and big femoral heads and to correlate them with the results of the Finite Element Analysis. In the period from 1/1/2006 until today 90 patients (33 men and 57 women) with mean age 62,4 years have undergone primary THA. The patients were clinically and radiographically evaluated preoperatively, as well as postoperatively, in regular time intervals (1st, 3rd, 6th, 12th month and every year afterwards). The clinical assessment was based on two scales, Harris Hip Score (HHS) and Merle d’ Aubigne (MDA) score, whereas the radiographic on Engh criteria. The mean follow up was 16 months. The mean preoperative HHS and MDA score were 45 and 10,3 respectively, whereas 89 and 16,74 at the last evaluation. The mean Engh score was 16,12. No incidence of dislocation, infection and cup or stem adverse effect occurred. We demonstrate extensively, with respect to the used combination of neck and femoral head, the radiographic findings in the zones of Grün and Charnley, in the areas of the tip of the stem and the calcar, as well as the resulting clinical manifestations. The early clinical and radiological data are in line with the increase in the stresses and strains on the upper part of the femur, which are revealed through the Finite Element Analysis.
To investigate the potential of biological fixation of cementless total hip prosthesis in patients over 75 years old, with diagnosed osteoporosis. Between 1994–2000, 30 patients (mean age 77.3 years) underwent total hip arthroplasty (THA). Twenty-two (22) patients, 10 male and 12 female, were found at the last follow-up, which ranged from 1, 5–7 years (mean follow-up, 3 years). THA was performed due to primary osteoarthritis (n=16), subcapital fracture (n=4), or dysplastic hip (n=2). Eight (8) smooth, tapered design (CLS) and 14 proximally porous coated prostheses were implanted. Smgh index was used for the evaluation of osteoporosis and modified Harris Hip Score was used for the clinical evaluation of each patient. Modified Wixon score was used for the evaluation of stability probability of the tapered stem. Engh score was calculated for the evaluation of osseointegration of the porous coated implants. Pre and post-operative mean Singh index was grade 4. Mean modified Harris Hip Score at the last follow-up was 88.6. For the CLS-Spotomo stem a stable fixation probability was calculated at 74.8%, while possible instability was calculated at 48.17%. Porous coated stems provided +13.45 mean. Engh score, implying satisfactory fixation of the implant. Post-operative systematic complications are not reported, in contrast to 3 dislocations in the first post-operative period, which were treated by closed reduction. In patients over 75 years old, with possible cardiopulmonary disease, cementless total bip arthroplasty offers a reliable treatment, regardless the presence of osteoporosis. Satisfactory osseointegration and absence of systematic complications is compromised by the high cost of titanium implants.