Osteloysis following metal-on-UHMW polyethylene Total Hip Arthroplasty (THA) is well reported, as is lack of osteolysis following Ceramic-on-Ceramic (CoC)THA. Early ceramic failures did report some osteolysis, but in flawed implants. As 3rd and now 4th generation ceramic THAs come into mid- and long-term use, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. Osteolysis reported after 3rd generation CoC THA often included metallosis due to neck rim impingement. In our department we have revised only 2 hips in over 6000 CoC THAs for osteolysis. Both had evidence of metallosis as well as ceramic wear. The technique used by Radiologists for identifying the nature of lesions on CT is the Hounsfield score which will identify the density of the tissue within the lucent area. It is common for radiologist to have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA which states there is osteolysis? Revision of such implants in elderly patients has a high risk of morbidity and mortality. This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term third generation ceramic-on-ceramic uncemented hip arthroplasties in our department.Introduction
Objectives
Total Hip Arthroplasty (THA) using the Direct Anterior Approach (DAA) is a muscle sparing approach which promotes early mobilisation of patients. It is a technically challenging approach shown to have a high rate of complications, especially during the learning curve. Here we present the results of 157 cases of THA via a DAA on a standard theatre table, with a minimum of 6 months follow-up. The authors conducted a prospective study on a group of 149 consecutive patients undergoing 157 cementless primary THAs for coxarthrosis, 8 bilateral. The same surgical technique was used in all patients, performed by the senior author WLW at a single centre. The average age of the patients at time of surgery was 69 years, 78% were female and 57% were right sided. All implants were uncemented, with bearings being ceramic on ceramic or Ceramic on highly cross-linked polyethylene. Patients were assessed clinically and radiographically pre- and post-operatively at 6 weeks, 6 months, 1 and 2 years. Intra-operatively, navigation was used to guide cup position and assess offset and leg length.Background
Materials & Methods
The 21st Century has seen ceramic bearings become an increasingly popular choice in total hip arthroplasty due to their high wear resistance and inert wear debris without osteolysis promising a long term bearing solution. Early ceramic bearings were hindered by fracture but improved manufacturing processes and materials subsequently produced stronger ceramics. These third generation ceramics showed greatly reduced fracture rates but there is limited evidence in the literature reporting their long term survival and wear characteristics. The purpose of this study was to determine osteolysis and survival rates of Alumina ceramic bearings in cementless total hip arthroplasties with a minimum follow-up of 15 years. We analyzed a series of 301 third-generation alumina-on-alumina cementless primary total hip replacements in 283 patients. The average age of the patients at the time of the arthroplasty was fifty-eight years, 51% were in women and 54% were right sided. All procedures were performed using the same surgical technique and the same implant at a single centre. Patients were followed up at six weeks, one, two, five, ten and 15 years. At 15 years postoperatively 46 patients (17%) had died of unrelated causes and 31 (10.2%) were lost to follow-up. Patients were assessed clinically and radiographically. Retrieved bearings were analyzed for wear.Introduction and Aims
Methods
The aim of this study is to describe the influence of sitting and standing posture on sagittal pelvic inclination in preoperative total hip replacement patients to assist with correct acetabular component positioning. Lateral radiographs of the pelvis and lumbar spine in sitting and standing of preoperative hip arthroplasty patients with primary hip osteoarthritis were extracted. Pelvic tilt was measured using the vertical inclination of a line from the ASIS to pubic tubercle. Sacral inclination was measured as the angle between the anterior surface of the sacrum and a horizontal reference. Figure one is a representation of the pelvic tilt angle and sacrel inclination angle taken during standing. The Cobb angle of the lumbar spine was recorded represented for a sitting patient in figure 2. Hip flexion was recorded (figure 2).Purpose
Methods
Pseudo-patella baja (PPB) describes narrowing of the distance between the patella and the tibia without shortening of the PT and occurs following Total Knee Arthroplasty (TKA), where the tibial prosthesis plus insert are thicker than the resected tibia. Soft tissue balancing is an important factor in the success of TKA, but if extensive may necessitate the use of thicker tibial inserts with the risk of creating a PPB. Patients who undergo extensive soft tissue releases during TKA, with resultant use of thicker tibial inserts will develop a PPB, with increased risk of patella pathology. 506 patients aged 40-90 years underwent 526 Kinemax TKAs, performed by 7 surgeons in 5 centres between 1999 and 2002. The extent of soft tissue releases and the thickness of tibial inserts were recorded. Pre- and post-operative lateral radiographs were measured by an independent observer, using the Caton-Deshamps method to assess patella position. The patients were assessed using the Oxford Knee Score and the American Knee Society Clinical Rating System, with a minimum follow-up of 12 months. 1. TKA surgery creates a Pseudo-Patella Baja. Excluding patients with a pre-operative patella baja, PPB was introduced into 26.7% of patients. (p=0.000). 2. The incidence of pseudo-patella baja increased with the extent of soft tissue release; Minimal, Moderate or Extensive. (p=0.000). 3. The incidence of pseudo-patella-baja increased with increases in insert thickness. Three groups were identified: Inserts 8 mm, inserts 10-12mm, and inserts 15-22 mm. (p=0.035). There was no correlation between the incidence of PPB and changes in clinical or functional outcome, as measured using the OKS and AKSS. Pseudo-patella baja occurs in 26% of all patients following TKA, and in 46% of patients in whom extensive soft tissue releases have been performed and/or large tibial inserts have been used. At 12 months, no detrimental outcomes were attributable to the incidence of pseudo-patella baja.
Soft tissue balancing is an important factor in the success outcome of TKA, but if extensive can necessitate the use of thicker tibial inserts. This may alter the position of the patella in relation to the tibia and increases the risk of creating a pseudo-patella baja.
TKA surgery creates a Pseudo-Patella Baja. Excluding patients with a pre-operative patella baja, pseudo patella baja was introduced into 25.6% of patients. (p=0.00). Extensive soft tissue releases during TKA are associated with a 100% increased in the incidence of pseudo patella baja compared to more moderate soft tissue releases. (p=0.002). The use of large tibial inserts is associated with a significant increase in the incidence of pseudo-patella-baja, compared to smaller inserts. Three groups were identified: Small Inserts 8 mm, Medium inserts 10–12mm, and Large inserts 15, 18 &
22 mm. (p=0.042). There was no correlation between the incidence of a pseudo-patella baja and changes in clinical or functional outcome, including range of motion, as measured using the OKS and AKSCRS.
TKA surgery creates a Pseudo-Patella Baja. PPB was introduced into 26.7% of patients. (p=0.000). The incidence of pseudo patella baja increased with the extent of soft tissue release. (p=0.000). The incidence of pseudo-patella-baja increased with increases in insert thickness. (p=0.035). There was no correlation between the incidence of PPB and changes in outcome, as measured using the OKS and AKSS.
We assessed the reproducibility and accuracy of four ratios used to measure patellar height, namely the Blackburne-Peel, Caton-Deschamps, Insall-Salvati and modified Insall-Salvati, before and after total knee arthroplasty. The patellar height was measured, by means of the four ratios, on the pre- and post-operative lateral radiographs of 44 patients (45 knees) who had undergone total knee arthroplasty. Two independent observers measured the films sequentially, in identical conditions, totalling 720 measurements per observer. Statistical analysis, comparing both observers and ratios, was carried out using the intraclass correlation coefficient. Before operation there was greater interobserver variation using either the Insall-Salvati or modified Insall-Salvati ratios than when using the Caton-Deschamps or Blackburne-Peel methods. This was because of difficulty in identifying the insertion of the patellar tendon. Before operation, there was a minimal difference in reliability between these methods. After operation the interobserver difference was greatly reduced using both the Caton-Deschamps and Blackburne-Peel methods, which use the prosthetic joint line, compared with the Insall-Salvati and modified Insall-Salvati, which reference from the insertion of the patellar tendon. The theoretical advantage of using the Insall-Salvati and modified Insall-Salvati ratios in measuring
