Treatment of femoral neck fractures applying conventional osteosynthesis with three parallel screws (CFIX) is associated with high complication rates. A novel method of biplane double-supported screw fixation (BDSF) was described. We aimed to evaluate the BDSF results compared to CFIX.
Materials and methods: Applying BDSF, two out of three medially diverging cannulated screws are buttressed on the inferior neck cortex. Biomechanically, the most effective component is the inferior screw placed at an obtuse angle and supported on a large area along the inferior and posterior femoral neck cortices following its spiral anterior curve.
Clinical investigation: Different centers worldwide reported that BDSF is applied in 367 patients with displaced femoral neck fractures. Bone union rate and healing complications are evaluated.
Biomechanical and Finite element model (FEM)-analysis: Two biomechanical tests are performed in different centers, comparing BDSF to CFIX, where instrumented cadaveric femoral pairs are tested, and axial stiffness, AP-bending and failure load are evaluated.
FEM-analysis is performed in two University centers and results are evaluated.
Results: In comparison to CFIX, BDSF provides supreme stability for cannulated screw fixation, achieving up to 44% higher axial fixation strength in vitro and a bone union rate of up to 96% in the clinical practice, being much higher than the CFIX rate, with similar rates of AVN. FEM revealed 40% higher failure load and 20% less stresses on the calcar area for BDSF vs. CFIX.
Conclusion: With its innovative biomechanical concept, BDSF achieves much stronger osteosynthesis construct, allowing immediate full weight-bearing and better clinical outcomes.

Introduction: Total hip arthroplasty (THA) in developmental dysplasia of the hip (DDH) is challenging due to diminished periacetabular bone stock and the highly placed femoral head. Although the anatomical reconstruction of the hip is the main aim of the procedure, good long-term clinical outcomes of the high hip center technique have also been reported. The aim of this study was to compare the knee gait parameters of “high hip center technique” with “anatomical reconstruction of the hip” in patients with unilateral DDH. Methods: A total of 20 patients who underwent total hip arthroplasty due to Crowe type III-IV DDH and completed 2 years of follow-up were included in the study. Group 1 comprised 10 patients who underwent anatomical hip center reconstruction, while Group 2 comprised 10 patients who underwent high hip center reconstruction. The gait characteristics of patients were examined through markers placed in certain anatomical regions, the cameras placed around, and the force plates embedded in the walking platform. Results: The average maximum extension of the knee on operated side was significantly lower in Group 2 (-9.5°±4.8) than in Group 1 (-5.1°±4.4)(p=0.044). The average maximum longitudinal knee joint force on operated side was found to be significantly higher in Group 2 compared to Group 1 (p=0.041). Conclusions: The unilateral high hip center technique has been shown to restrict the dynamic knee range of motion and increase the loads on the knee. Thus, high hip reconstruction can adversely affect the gait parameters and put the knees at risk for osteoarthritis.

Acetabular fractures in the elderly population are usually the consequence of a simple low-energy fall. Due to ageing of the population, the number of elderly patients with fractures of the acetabulum is rapidly increasing. Management of these fractures remains controversial with options including conservative treatment, percutaneous fixation, open reduction and internal fixation and hip arthroplasty. A 78 year old male patient sustained a fall from his own height that resulted in a left acetabular fracture with the typical characteristics of geriatric acetabulum fracture of anterior column displacement, quadrilateral plate fragment, comminution and dome impaction. The patient was submitted to reconstruction of the acetabulum with a Burch-Shneider ring and autologous bone graft and total hip arthroplasty. The patient presents with good functional results and residual hip pain. Acetabular fractures in the elderly pose unique challenges to the orthopaedic surgeon.Not only comorbidities with its subsequent increase in perioperative complications, but also the poor bone quality tends to result in unfavorable outcomes. Conservative treatment for these patients seems to lead to unsatisfactory functional results and high mortality rates, due to long periods of bed rest or immobilization. Open reduction and internal fixation is technically difficult and prone to failure . Acute primary hip replacement has shown good functional results but its use in the elderly remains controversial. Due to the fracture pattern, poor bone quality and comminution, individualized treatment approaches are needed in order to achieve a stable implantation of an acute hip arthroplasty

Background: Usual in revision arthroplasty, acetabular reconstruction is less common in primary THR. In devolopping countries, delayed diagnosis of coxarthrosis, the sequellaes of infection and trauma are frequently indications of acetabular reconstruction. Objective: Assess the results of acetabular reconstruction using the kerboull device in these particular conditions. Material and method: we peform a 10-years retrospective study including 30 cases of acetabular reconstruction using Kerboull device in primary hip arthroplasty. Mean age was around 44ans +/- 17 with a sex-ratio of 1,3. Hip post-traumatic injuries and sequellae was most common indications (n=13- 40,6%).Type 2 of the Sofcot classification of bone loss was found in 62,5% cases. Bone grafting was done in 24 cases using cephalic bulked autograft. Size 5 of Kerboull device was most common (n=19-59,4%). The function of the hip was evaluated using the Postel Merle d’Aubigné (PMA) score. The post-operative and final follow-up radiographs were compared to assess migration of the implant by SOO( Société de l’Orthopédie de l’Ouest) zoning. Results : By 5-years mean follow-up, PMA mean score increases from 9,87 preoperatively to 16,68 postoperatively. Vertical and transversal postoperative positioning of the implant was in SOO zone IIB in 53,1%. Device orientation was 48,88° on average. The acetabular component positioning was good in 17 hips.
At final follow-up, no modification of the positioning and the orientation was noted. However, 3 dislocations and 3 PJI was managed. Conclusion: The Kerboull device is a good option in primary hip arthroplasty for developing countries with good functional and anatomical results.

Introduction: modular dual mobility cup (mod DMC) has been introduced during the last decade to overcome this limitation of monoblock MDC. Early results are encouraging, however additional bearing surfaces decrease the effectiveness of the large head and increased the potentiality of corrosion. Material and method: we conducted a qualitative systematic review on all published and available reports in worldwide databases The inclusion criteria considered primary hip arthroplasties and hip revisions studies where modular dual mobility prosthesis has been implanted.
Results: 327 papers were identified. After screening for duplicate and eligibility we identified 229 publications, 212 articles were excluded because reporting DMC without modularity.Of the 17 included articles, 7 were prospective case series, 10 were retrospective case series. Discussion: all the modular implant had a reduction of the JD compared with monoblock cup due to the presence of a modular CoCr alloy liner. Even if at least seven companies have developed this type of implants, the majority of studies reported about MDM stryker liner. Good clinical outcomes have been reported as well as low incidence of dislocations and revisions. Elevated serum cobalt ions were present in about 5 %of patients at a mean follow-up; the serum value decrease in the majority of patients between 1 and 2 years. No patient was revised for metal ion related complications. Continued serum metal ion surveillance is recommended to ensure the safety of modular DMC implants.

Introduction: Acetabular bone loss remains a challenge in revision total hip arthroplasty (THA). Trabecular titanium (TT) augments are commonly used for uncontained bone defects as they provide good initial stability and allows for bony ingrowth. The aim of the present study was to assess the short to medium term outcomes of TT augments in revision THA. Methods: Prospective data was collected of all the revision THA performed using TT augments (Limacorporate) between 2013 to 2017 in our institution. Functional outcomes were measured using Oxford Hip Score (OHS) both preoperatively and post-operatively at subsequent follow ups. Plain x rays were assessed for radiological outcomes and Kaplan Meier survival analysis was performed to analyse the survivorship of the acetabular components. Results: 23patients with TT augment had a mean follow up of 5.3 years. Majority of the defects were 3a and 3b Paprosky classification (43.4% and 39.1% respectively). Amongst them, the acetabular component of the 2 patients (8.7%) had vertically migration and were considered as failures. Mean pre-operative OHS was 16.6 and the most recent mean post-operative OHS was 35.2 (p <0.001). The survival analysis showed a cumulative survivorship of 91.1% (CI 77.1-105.1) at 5 years. Conclusion: At 5.3 years follow-up, 91.3% of augments had successfully incorporated with cumulative survivorship of 91.1%. In our experience, TT augments when used in revision THA provide good short to medium term outcomes. Our study is the first to report on 5 year clinical and radiological outcome of TT augments.

Background: In revision total hip arthroplasty (THA) cases with preserved femoral metaphyseal bone, tapered proximally porous-coated “primary” femoral stems may be an option. The objective of this study was to compare outcomes of patients with Paprosky I/II femoral bone loss undergoing revision THA with either a primary metaphyseal-engaging cementless stem or a revision diaphyseal-engaging stem.
Methods: This was a retrospective analysis of 70 patients with Paprosky I or II femoral bone loss who underwent femoral revision. 35 patients who were revised using a primary cementless femoral stem were compared to 35 patients who underwent femoral revision using a revision diaphyseal-engaging stem. The groups were similar regarding age, gender, BMI, and ASA. Clinical and radiographic outcomes and complications were compared over an average follow up of 2.9 years (SD 1.4).
Results: Revision THA was most commonly performed for periprosthetic joint infection (N=27, 38.6%). The groups were similar with regards to Paprosky femoral classification (p=0.56), length of stay (p=0.68), discharge disposition (p=0.52), operative time (p=0.20), and complications (p=0.35). There were no significant differences between primary and femoral stem subsidence (0.12 vs. 0.75mm, p=0.18), leg length discrepancy (2.3 vs. 4.05mm, p=0.37), and Hip Disability and Osteoarthritis Outcome Scores (73.1 [SD 21.1] vs 62.8 [SD 21.7], p=0.088). No patient underwent additional revision surgery involving the femoral component.
Conclusion: Use of modern primary cementless femoral stems is a viable option for revision hip arthroplasty in the setting of preserved proximal femoral metaphyseal bone. Outcomes are comparable to those of revision stems and offer potential benefits.