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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 98 - 98
1 May 2016
Oinuma K Tamaki T Kaneyama R Higashi H Miura Y Shiratsuchi H
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Introduction. Bulk bone grafting is commonly used in total hip arthroplasty (THA) for developmental dysplasia. However, it is a technically demanding surgery with several critical issues, including graft resorption, graft collapse, and cup loosening. The purpose of this study is to describe our new bone grafting technique and review the radiographic and clinical results. Patients and Methods. We retrospectively reviewed 105 hips in 89 patients who had undergone covered bone grafting (CBG) in total hip arthroplasty for developmental dysplasia. We excluded patients who had any previous surgeries or underwent THA with a femoral shortening osteotomy. According to the Crowe classification, 6 hips were classified as group I, 39 as group II, 40 as group III, and 20 as group IV. Follow-up was at a mean of 4.1 (1 ∼ 6.9) years. The surgery was performed using the direct anterior approach. The acetabulum was reamed as close to the original acetabulum as possible. The pressfit cementless cup was impacted into the original acetabulum. After pressfit fixation of the cup was achieved, several screws were used to reinforce the fixation. Indicating factor for using CBG was a large defect where the acetabular roof angle was more than 45 degrees and the uncovered cup was more than 2 cm (Fig.1). The superior defect of the acetabulum was packed with a sufficient amount of morselized bone using bone dust from the acetabular reamers. Then, the grafted morselized bone was covered with a bone plate from the femoral head. The bone plate was fixed with one screw to compact the morselized bone graft. The patient was allowed to walk bearing full weight immediately after surgery. We measured the height of the hip center from the teardrop line and the pelvic height on anteroposterior roentgenograms of the pelvis and calculated the ratio of the hip center to the pelvic height. We defined the anatomical hip center as the height of the center less than 15 % of the pelvic height, which was nearly equal to 30 mm, because the mean pelvic height was 210 mm. Results. The mean height of the hip center was 9.8 (4.1∼18.0) % of the pelvic height and the 101 (96.2%) cups were placed within the anatomical hip center. Radiographically, in all patients, the host-graft interface became distinct and the new cortical bone in the lateral part of the plate bone appeared within 1 year after surgery (Fig.2, 3). We observed no absorption of the plate bone graft and no migration of the cup at the last follow-up. Conclusion. CBG technique is simple, because the bone graft is always performed after the pressfit of the cup is achieved. Moreover, patients require no partial weight bearing postoperatively, because the cup is supported by the host bone with the pressfit and additional screws. The CBG technique would be an excellent option for the reconstruction of the acetabulum in patients with severe dysplasia to avoid a high hip center and bulky bone grafting


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_2 | Pages 63 - 63
1 Jan 2016
Ishii M Takagi M Kawaji H Tamaki Y Sasaki K
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Acetabular reconstruction of extensive bone defect is troublesome in revision total hip arthroplasty (rTHA). Kerboull or Kerboull type reinforcement acetabular device with allobone grafting has been applied since 1996. Clinical results of the procedure were evaluated. Patients. One hundred and ninety-two consecutive revision total hip arthroplasties were performed with allograft bone supported by the Kerboull or Kerboull type reinforcement acetabular device from 1996 to 2009. There were 23 men and 169 women. Kerboull plates were applied to 18 patients, and Kerboull type plates to 174. The mean follow up of the whole series was 8 years (4–18years). Surgical Technique. The superior bone defect was reconstructed principally by a large bulky allo block with plate system. Medial bone defect was reconstructed by adequate bone chips and/or sliced bone plates. After temporally fixation of bulky bone block with two 2.0mm K-wires, it was remodeled by reaming to fit the gap between host bone and plate, followed by fixation to the iliac bone by screws. Finally, residual space of the defect between host bone and the fixed plated was filled up with morselized cancellous bones, bone chips, and/or wedged bony fragments with impaction. This method was sufficiently applicable to AAOS Typeâ�, II, and III bone defects. In case of AAOS Typeâ�£, the procedure was also available after repairing discontinuation between distal and proximal bones by reconstrusion plate or allografting with tibial bone plates or sliced femoral head. Results. Nine patients (4.7%) required revision surgery (infection 5, breakage 3, and malalignment 1). The plate breakage was observed in 8 joints (4.2%). Three patients had no symptoms after the breakage. Three required revision, but the other cases were carefully observed without additional surgical intervention. Ten-year survival rate by Kaplan-Meier method was 96.6% when the endpoint was set revision by asceptic loosning. Conclusions. This study indicated that acetabular allograft reconstructions reinforced by Kerboull or Kerboull type acetabular device were able to recover bone stock with anatomic reconstruction of femoral head center, thus providing satisfactory clinical results in middle term period


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLIV | Pages 18 - 18
1 Oct 2012
Bou-Sleiman H Nolte L Reyes M
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Bone fixation plates are routinely used in corrective and reconstructive interventions. Design of such implants must take into consideration not only good surface fit, but also reduced intra-operative bending and twisting of the implant itself. This process increases mechanical stresses within the implant and affects its durability and the functional outcome of the surgery. Wound exposure and anaesthesia times are also reduced. Current population-based designs consider the average shape of a target bone as a template to pre-shape the implant. Other studies try to enhance the average design by optimising surface metrics in a statistical shape space. This could ensure a low mean distance between the implant and any bone in the population, but does not reduce neither the maximum possible distances nor directly the mechanical forces needed to fit the implant to the specific patient. We propose a population-based study that considers the bending and torsion forces as metrics to be minimised for the design of enhanced fixation plates. Our aim is to minimise the necessary intra-operative deformations of the plates. In our approach, we first propose to represent a fixation plate by dividing it into discrete sections lengthwise and fitting a plane to each section. The number of sections depends on the size of the implant and anatomical location. It should be small enough to capture the anatomical curvatures, but large enough not to be affected by local noise in the surface. Surface patches corresponding to common locations for plate fixations are extracted from 200 segmented computed tomography (CT) images. In this work, distal lateral femoral patches are considered. A statistical shape model of the patches is then computed and a large population of 2,197 instances is generated, evenly covering the natural statistical variation within the initial population. These instances are considered as both bone surfaces and potential new designs of the contact surface of the fixation plate. The key formulation of our solution is to examine the effect of deforming each section of the implant on the rest of the sections and compute the amount of bending and torsion needed to shape one patch to another. Each instance of the population is fitted to all others and the maximum bending and torsion angles are recorded. A similar process was applied for the mean of the population. The goal is to pick from the population the shape that simultaneously minimises the bending and torsion angles. The maximum required bending was reduced from 25.3® to 19.3® (24.72% reduction), whereas the torsion component was reduced from 12.4® to 6.2® (50% reduction). The method proposed in this abstract enhances the current state-of-the-art in orthopaedic implant design by considering the mechanical deformations applied to the implant during the surgery. The obtained results are promising and indicate a noticeable improvement over the standard pre-contouring to the population mean. We plan to further validate the method and as a future outlook, we intend to test the approach in real surgical scenarios


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLIV | Pages 65 - 65
1 Oct 2012
Haselbacher M Sekyra K Mayr E Thaler M Nogler M
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In the last years custom-fit cutting guides using magnetic resonance imaging (MRI) were introduced by orthopedic surgeons for total knee arthroplasty (TKA). One of the advantages of these shape-fitting jigs is the possibility to transfer the preoperative planning of the TKA directly to the individual patient's bone. However, one has to be aware, that the jigs are designed for single-use and have to be custom made by an external manufacturer. This increases the cost of implantation and unlinks the surgeon from this process. In addition a potentially necessary adjustment of the preoperatively planned implant size and position in a surgical situation is not possible. The purpose of our development was to combine the advantages of custom-fit cutting guides as a 3-D-computer-assisted planning tool with the option to adjust and improve the preoperative planning and the jig in the actual surgical situation. In addition no outside jig manufacturing would occur in this concept. This leaves the surgeon in control of the entire process. The purpose of this study was to examine the reliability of this screw-based shape – fitting system. In order to do this we assessed the inter- and intra-observer reliability of the recurrent placement of the plate on a set of bone samples with preset screws. We developed a plate with the dimension of 66 × 76 × 10 mm, containing 443 threaded holes. A connector for further instrumentation is mounted on the proximal part of the plate,. As the plate and the screws are made of aluminum and steel, sterilization is possible. After computer tomography (CT) scans were taken from three human femoral bones, eight to nine variably positioned screws (50.45 mm length, 2.75 mm diameter), reversibly fixed by locknuts, formed an imprint of a bone's surface. For calculating precise screw positions, a computer-based planning software was developed resulting in a three-dimensional reconstruction of the bony surfaces. The plate was integrated in the 3-D reconstruction software. With a defined distance to the distal part of the femurs, allowed the proper length and position of the screws to be calculated. These calculations were transferred to the screws on the real plate. In the next step the plate was positioned on the bony surface and after reaching the planned position the plate's connector was rigidly fixed to the bone. The plate was removed to give place to link saw jigs to the connector. Planning and setting of the plate and the screws were conducted on three femoral bones. Examinations were performed by five investigators with ten repetitions on each bone with three distinct plates. Intra- and inter-observer variability was assessed by measuring the variation in plate position between the trials. The jigs were placed in a mean frontal tilting (medial to lateral) of 0.83°. The mean axial tilting (proximal to distal) was 1.66° and the mean shift on the axis from proximal to distal 8.48 mm. The shift and the tilting were significantly bone dependent but not user dependent. Compared with previous studies the deviation from the mechanical axis were comparable with conventional TKA (2.6° and 0.4°), computer assisted TKA (1.4° and 1.9°) and Custom-fit TKA (1.2°). We developed a preoperative planning system for TKA that allows a transfer of the planning and the calculated imprint of the bones surface on a grid-plate during surgery by the surgeons themselves. Neither external manufacturers to create a fixed device nor a navigation system is necessary. Results showed the functioning of the screw – based shape fitting technique within the accuracy mentioned above. These findings are encouraging to do further research to examine the ideal number of screws to offer a perfect fitting


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 11_Supple_A | Pages 141 - 146
1 Nov 2012
Minas T

Hyaline articular cartilage has been known to be a troublesome tissue to repair once damaged. Since the introduction of autologous chondrocyte implantation (ACI) in 1994, a renewed interest in the field of cartilage repair with new repair techniques and the hope for products that are regenerative have blossomed. This article reviews the basic science structure and function of articular cartilage, and techniques that are presently available to effect repair and their expected outcomes.