Malpositioning of the acetabular cup during total hip arthroplasty increases the risk of dislocation, edge loading, squeaking and can be responsible for early wear and loosening. We hypothesized that the use of three-dimensional visualization tools showing during surgery the planned cup position relatively to the acetabular edge would increase the accuracy of cup orientation. The purpose of this study was to compare 3D planning-assisted with freehand insertion of the acetabular cup. A randomized, controlled, prospective study of two groups of twenty eight patients each was performed. In the first group, cup positioning was guided by 3D views of the cup within the acetabulum based on a three-dimensional preoperative planning (Figure 1). In the control group, the cup was placed freehand. All of the patients were operated on by the same surgeon through a direct anterior approach in supine position. Cup anteversion and abduction angles were measured on three-dimensional computed tomography reconstructions for each patient by an independent observer. We analyzed the accuracy of both methods. The main evaluation criterion was the percentage of outliers according to the Lewinneck safe zone.Introduction
Methods
Because of post traumatic mal union or constitutionnal intraosseous femoral or tibial deviation, an extra articular deformity may be present in patients requiring TKR. In those cases, recreation of the mechanical axis will affect the orientation of femoral or tibial bone cuts and soft tissue balance. In those important deformities, an extra articular correction may be necessary. Between 1998 and 2013 we performed 31 TKR associated with femoral (6 cases) or tibial (25 cases) osteotomy in one time surgery. This study was prospective and the patients were examinated at 1, 2, 5, 10 and 15 years for the first patients. There were 17 males (one bilateral case) and 13 females with a 63 years average age (from 29 to 79). The deformity was constitutionnal in 14 cases, post trauma in 9 cases, post osteotomy in 8 cases. The extra articular deformity was between 10° and 35°: 15 in varus, 11 in valgus, 2 multidirectionnal, 1 intraosseous flessum, 1 important translation and 1 rotational deformity. In all the cases we used a long stem implant in the osteotomized bone: an osteosynthesis was performed in 26 cases (7 plates, 19 stapples). A posterostabilised prosthesis was used in 28 patients, a CCK implant in 3. We studied pre and post operatively with a 3 to 17 years follow up, IKS scoring, knee motion, knee stability and radiologicaly, HKA, tibial and femoral mechanical angle. In the knees with a varus deformity the average HKA was 158° before surgery and 181 after osteotomy combinated with TKR. In the valgus cases, the average HKA was 198° pre and 179° post operatively. Complications consisted in 1 peroperative fracture, 1 extension lag of 15° and 1 hematoma. TKR associated with osteotomy seems to be a possible alternative in patients with severe constitutional or post traumatic extra articular deformities after discussion of the other solutions: osteotomy and TKR in two times surgery (particulaly in young patients) or constraint TKR (rotating hinged implants) in patients over 80 years of age.
Recent literature points out the potential interest of standing and sitting X-rays for the evaluation of THA patients. The accuracy of the anterior pelvic plane measures is questionable due to the variations in the quality of lateral standing and sitting X-rays. The EOS® (EOS imaging, Paris, France) is an innovative slot-scanning radiograph system allowing the acquisition of radiograph images while the patient is in weightbearing position with less irradiation than standard imagers. This study reports the “functionnal” positions of a 150 THA cohort, including the lateral orientation of the cups. The following parameters were measured: sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI) and anterior pelvic plane (APP) sagittal inclination (ASI), frontal inclination (AFI) and planar anteversion (ANT). Irradiation doses were calculated in standing and sitting acquisitions. Variations of sagittal orientation of the cup were measured on lateral standing and sitting images. Descriptive and multivariate analysis were performed for the different parameters studied.Background
Methods
A decrease of 15% in femoral off-set (FO) was reported to generate a weakness of the abductor muscle after THA, which may increase the risk of limping and dislocation. However, this value was defined under experimental conditions using a CYBEX machine, which does not correspond to daily life activities. To our best knowledge, there is no reported study about the effect of the FO alteration on the gait, following THA. To assess the functional consequences of an alteration in the FO, a prospective comparative study was carried out and it included patients who underwent THA for primary osteoarthritis. In order to select only patients with an isolated FO alteration, the three-dimensional hip anatomy was analysed preoperatively and post-operatively with CT-scans using HipPlan Software. Three groups were defined according to the FO alteration: 15% decrease, restored and 15% increase. The exclusion criteria were: the presence of an arthroplasty or of an associated pathology on the contra-lateral or the same limb, a spine disease and a non-restoration of the other hip parameters (center of rotation, limb length). 26 patients were included: 12 restored, 9 decreased FO and 5 increased FO. The patients were composed of 20 women and 6 men with an average age of 67.7 ± 9 years. All the patients were assessed clinically, pre-operatively and 1 year after surgery with 4 scores: the Poste Merle d'Aubigné score, the Harris score, the womac score and the quality of life score SF12. A gait analysis was performed at 1 year follow-up using an ambulatory device (Physilog (3)) under normal walking conditions. The patients were asked to walk at their usual normal speed for 30 metres in a standardized corridor: Each limb was compared to the contra-lateral healthy limb.Introduction
Materials and Methods
The ceramic-on-ceramic strategy in acetabular revision faces potential limitations due to the femoral stem, as the implantation of ceramic ball head on a previously used taper is not recommended. Delta (r) ball heads with titanium sleeves have been proposed to avoid femoral revision. The study reports a minimum 3 years follow-up experience using this strategy. This series report 42 revisions (16 metal-on-metal and 26 PE THA) in 39 patients (mean age 59.2 years, mean BMI 25). The 12-14, 5°46 sleeves were used in 24 cases and 10-12, 6° in 18 cases. (32mm ball head in 26 cases and 36 mm in 16 cases). Titanium serum level has been studied to detect the potential release from the sleeve-taper interface.Introduction
Materials and Methods
Wear performances and fracture toughness of the alumina-matrix composite (AMC) Biolox-delta(r) are pointed out in the literature. This study is a prospective monocentric evaluation of 32 and 36 mm AMC/AMC bearing surfaces. 141 THA were included prospectively since 2006 in 127 patients. (62 females, 65 males, mean age 62, 2 years, mean BMI 25, 5). 134 cases were primary implantations. Mean follow-up is 40.9 months (29.8-53.4). In all patients we used the same cementless stem and cup. Clinical and radiological data were evaluated with a special attention for ceramic fracture and squeaking.Introduction
Material and methods
A high precision of three-dimensional (3D) computerised planning of THA was recently reported. However, there is no comparative study analysing the value of 3D planning comparatively to the planning made on X-rays using 2D templates A prospective comparative randomised study was carried out from 2008 to 2009, and included 2 groups of 32 patients who underwent THA for primary osteoarthritis. One surgeon performed all the procedures using a direct anterior approach. In one group, the planning was made on calibrated X-Rays using 2D templates. In the other group, a 3D planning was performed based on CT-scan using the Hip-Plan software. Post operatively, the final hip anatomy was analysed on X-Rays for the 2D group and on CT-scan for the 3D group.Background
Material and method
