The success of cementless total hip arthroplasty (THA) depends on the primary stability of the components. One of the biomechanical factors that comes into play is the mechanical quality of the bone. To our knowledge, there are no reported studies in the literature analyzing the impact of the preoperative bone mineral density on the outcomes of cementless THA. The goal of the study was to analyze the clinical results at 2 year follow-up according to the preoperative cancellous bone mineral density (BD). Our hypothesis was that the clinical outcomes were correlated to the BD. From January to June 2013, a prospective study included patients who underwent a cementless THA using a proximally shortly fixed anatomic stem. A 3D preoperative CTscan-based planning was performed according to the routine protocol using the Hip-Plan software in order to determine the hip reconstruction goals as well as the implants size and position. The Hounsfield bone density (BD) of the metaphyseal cancellous bone was computed in a volume (of 1 mm thick and of 1cm² surface) at the level of the calcar 10 mm above the top of the lesser trochanter and laterally to the medial cortical (Figure 1). Intra-and inter-observer repeatability measurements were performed. Patients were clinically assessed at 2 years follow-up using self-administered auto-questionnaires corresponding to the Harris and the Oxford scores. A Multivariate statistical analysis assessed correlations between clinical scores, age, gender, body mass index, and BD.Introduction
Material and methods
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.
Total hip arthroplaty (THA) using direct anterior minimal invasive (AMI) surgery is an attractive option to achieve a quicker habilitation. However, high complication rates were reported and very often related to technical difficulties at the time of surgery. We hypothesized that 3D preoperative planning may allow to anticipate these difficulties and to decrease the complications rates when using an AMI approach. A prospective observational study included 191 consecutive patients who underwent a primary cementless THA using an AMI. A 3D CT-scan based pre-operative planning was performed in order to anticipate the potential difficulties that may be encountered especially regarding the hip anatomy reconstruction and the implants stability. The components size and position were planned in order to restore the leg length, the offsets, and the anteversions. Postoperatively, a CT scan was performed in order to compare the final anatomy to the planning.Introduction
Material and methods
According to the literature, the gait does not return to normal after THA. However, the three-dimensional hip anatomy is usually not assessed before and after surgery. Our hypothesis was that an accurate reconstruction of the hip anatomy, based on a three-dimensional preoperative planning, may normalize the gait after THA. 18 consecutive patients, graded Charnley A, aged of 59.3 ±13 years, underwent THA for unilateral primary osteoarthritis using a direct anterior minimal invasive approach. A 3D computerised planning was performed, the implants size and position were chosen in order to restore, the leg length, the off-set, the centre of rotation and the anteversion angles (Figure 1). At 1 year follow up, a 3D gait analysis was performed and included 29 parameters describing the kinetics and the kinematics. Each patient was compared to himself using the contra-lateral healthy hip, as well as to a group of 13 healthy volunteers.Introduction
Material and method
