Surgical treatment of fragility sacrum fractures with percutaneous sacroiliac (SI) screw fixation is associated with high failure rates in terms of screw loosening, cut-through and turn-out. The latter is a common cause for complications, being detected in up to 20% of the patients. The aim of this study was to develop a new screw-in-screw concept and prototype implant for fragility sacrum fracture fixation and test it biomechanically versus transsacral and SI screw fixations. Twenty-seven artificial pelves with discontinued symphysis and a vertical osteotomy in zone 1 after Denis were assigned to three groups (n = 9) for implantation of their right sites with either an SI screw, the new screw-in-screw implant, or a transsacral screw. All specimens were biomechanically tested to failure in upright position with the right ilium constrained. Validated setup and test protocol were used for complex axial and torsional loading, applied through the S1 vertebral body. Interfragmentary movements were captured via optical motion tracking. Screw motions in the bone were evaluated by means of triggered anteroposterior X-rays. Interfragmentary movements and implant motions in terms of pull-out, cut-through, tilt, and turn-out were significantly higher for SI screw fixation compared to both transsacral screw and screw-in-screw fixations. In addition, transsacral screw and screw-in-screw fixations revealed similar construct stability. Moreover, screw-in-screw fixation successfully prevented turn-out of the implant, that remained at 0° rotation around the nominal screw axis unexceptionally during testing. From biomechanical perspective, fragility sacrum fracture fixation with the new screw-in-screw implant prototype provides higher stability than with the use of one SI screw, being able to successfully prevent turn-out. Moreover, it combines the higher stability of transsacral screw fixation with the less risky operational procedure of SI screw fixation and can be considered as their alternative treatment option

Summary. Application of RSA in supine and standing positions allows pelvic fracture stability to be measured more accurately than current techniques. RSA may enable a better understanding of these injuries. Introduction. The in vivo stability of the pelvic ring after fracture stabilisation remains unknown. Plain radiographs have a low accuracy in diagnosing loss of fracture reduction over time. Radiostereometric analysis (RSA) is an accurate imaging measurement method that has previously been applied to measure the healing of other fractures. This pilot study investigated the potential application of RSA in supine and standing positions to measure pelvic fracture stability over time and under weightbearing load. Methods. Five patients with a similar type C pelvic ring disruption who were all operated on using the same surgical technique and had RSA markers inserted at the time of surgery. All five patients had a unilateral comminuted sacral fracture lateral to the sacral foramina treated with posterior plating and pubic rami fractures stabilised by external fixation for six weeks. All patients were mobilised partial weight bearing after regaining leg control. RSA examinations at 2, 4, 12, 26 and 52 weeks included three radiographic pairs taken in supine, standing and supine positions at each time point. Two additional RSA examinations were performed the day prior and post pin removal at 6 weeks. Results. All patients ambulated before the 2 week follow-up and progressed uneventfully. At latest follow-up, there were no complications. Minimal displacements (translations less than 0.3mm and rotations less than 0.5°) were recorded between the supine exams pre and post standing at 2 weeks. Hence, the supine examination was found to be a reliable position to measure the migration of the ilium over time. No loss of reduction was identifiable on plain radiographs over time. At 52 weeks, in contrast to plain radiographic results, RSA measurements revealed that one patient had a fracture migration greater than 4mm. Such large displacements could result in sacral nerve root transection, leading to devastating consequences, such as incontinence, for patients whose sacral fractures are through or medial to the sacral foramina. In one patient, the migration recorded for the apparent uninjured posterior complex side exceeded the migration of the injured side suggesting an unrecognised bilateral injury. Comparative RSA examinations pre and post external fixator removal demonstrated that in three patients the injured hemipelvis migrated greater than 2mm after the removal of the external fixator, which may be indicative that the fixator was removed prematurely. Discussion and Conclusion. The application of RSA allows accurate measurement of pelvic fracture stability which is difficult, if not impossible, to identify and quantify with any other imaging techniques. Hence, RSA has the capacity to enable a better understanding of pelvic ring injuries and optimise their treatment

Introduction. Since 2005, we have performed implantation of bone marrow-derived mononuclear cells for osteonecrosis of the femoral head in order to improve vascularization and bone repair. This study focused on early bone repair of osteonecrosis of the femoral head after transplantation of bone marrow-derived mononuclear cells (BMMNC). Patients and Methods. Twenty-two patients (30 joints) who had bilateral osteonecrosis followed for more than 2 years after BMMNC implantation were evaluated. Eight women and 14 men were included. Their mean age at surgery was 41 years (range, 18 to 64 years) and the mean follow-up period was 31 months. Pre-operative stage according to the ARCO classification was Stage 2 in 25 joints and Stage 3 in 5 joints. The mean volume ratio of osteonecrosis was 21%. For preparing BMMNC, about 700ml of bone marrow was aspirated from the ilium and centrifuged using a Spectra cell separator (Gambro). The BMMNC were seeded to interconnected porous calcium hydroxyapatite (IP-CHA) and implanted to the osteonecrotic lesion. As a control, cell-free IP-CHA was implanted for 8 patients (9 joints). A woman and 7 men were included. The mean age at surgery was 49 years (range, 28 to 73 years) and the mean follow-up period was 37 months. Preoperative stage was stage 2 in all patients. The mean volume ratio of osteonecrosis was 22%. At post-operative evaluations; progression of collapse, consolidation at reactive zone, post-operative course of volume rate of osteonecrosis, and bone absorption at osteonecrosis was assessed. Results. Shrinkage of osteonecrosis has been observed subsequent to bone consolidation at the transitional zone which progressed from 3 to 6 months post-operatively in the BMMNC-seeded group. Progression of collapse more than 2 mm was detected in 4 joints (13%), and hip arthroplasty was performed in 1 joint (3%). Consolidation at the reactive zone was detected in 28 joints (93%) and the volume rate of osteonecrosis significantly decreased by 12 months after surgery. Bone resorption at the osteonecrotic lesion was observed in 14 joints (47%). Meanwhile, subtle bone consolidation was detected after 12 months post-operatively in the control group. Progression of collapse was observed in 6 joints (67%) and further surgical treatments were needed in 3 joints (33%). Conclusion. This study found that BMMNC was beneficial to osteonecrosis of the femoral head from the viewpoint of prevention of collapse

Summary. From a large 3D Caucasian bone data base, female population had significantly larger acetabular anatomical anteversion angle and combined acetabular-femoral anteversion angle than that of male population. There was no significant difference in femoral neck anteversion angles between the groups. Introduction. Combined Anteversion (CA) angle of acetabular component and femoral neck is an important parameter for a successful Total Hip Arthroplasty (THA). The purpose of this study was to electronically measure the version angles of native acetabulum and femur in matured normal Caucasian population from large 3D CT data base. Our question was if there was any significant difference in CA between male and female population. Methods. 221 anonymous (134 males and 87 females) CT paired pelvic and femoral scans from normal Caucasian population with age range of 30–93 years old were analyzed. CT data was converted to virtual bones using custom CT analytical software. 1. (SOMA. TM. V.3.2). Acetabular Anatomical Anteversion (AA) angle as defined by Murray. 2. was selected. The acetabular rim plane was constructed by selecting 3 bony land marks from pubis, ilium and ischium. The AA was measured against pelvic frontal plane. Femoral neck Anteversion (FA) was measured between neck axis plane and the Coronal plane which was defined by posterior condyles. The neck axis plane was defined as being the plane passing through femoral neck axis and being perpendicular to the transverse plane which is defined by distal femoral condyles. The CA angle in standing position was computed as the summation of AA and FNA angles. All the measurements were performed for total, male and female populations. Student's t tests were performed to compare gender difference with an assumed 95% confidence level. The relationship between AA and FA for each gender was studied by the plot of AA and a function of FA. Results. The mean AA angle for total population was 25.8°, SD=6.52°. (male 24.8°, SD=5.91°, female was 27.3°, SD=7.12°. P=0.006). The mean FA angle for total population was 14.3°, SD=7.95°. (male 13.4°, SD=7.99°, female 15.6°, SD=7.76°. P=0.051). The mean CA angle for total population was 40.1°, SD=10.76°. (male 38.2° SD= 10.38 °, female 42.9° SD= 10.79 °. P=.0002). The plot of AA as a function FA is shown. The frequency distribution of CA angle is plotted for males and females. Discussion/Conclusion. The results showed both AA and CA angles were significantly smaller in the male than that in female. However there was no significant difference in FA between male and female. The plot of AA as a function of FA showed no correlation (R. 2. <.09) between the two angles for both male (R. 2. =.0097) and female (R. 2. =.0029). The FA angle of a femoral stem implant in THA may be smaller than that of natural femur, therefore a higher AA or higher posterior build up may be required for the acetabular component to achieve optimal function of a THA. This may be a more significant issue in female population. The limitations of this study was that this population did not have pathological conditions which could lead to THA. However, it should provide reference guidance comparing normal anatomy between male and female

Objectives

Microindentation has the potential to measure the stiffness of an individual patient’s bone. Bone stiffness plays a crucial role in the press-fit stability of orthopaedic implants. Arming surgeons with accurate bone stiffness information may reduce surgical complications including periprosthetic fractures. The question addressed with this systematic review is whether microindentation can accurately measure cortical bone stiffness.

Objectives

An experimental piglet model induces avascular necrosis (AVN) and deformation of the femoral head but its secondary effects on the developing acetabulum have not been studied. The aim of this study was to assess the development of secondary acetabular deformation following femoral head ischemia.

Objectives

The aim of this experimental study on New Zealand’s white rabbits was to investigate the transplantation of autogenous growth plate cells in order to treat the injured growth plate. They were assessed in terms of measurements of radiological tibial varus and histological characteristics.

Acetabular dysplasia was produced in 24 immature white rabbits. A rotational acetabular osteotomy was then carried out and radiological and histological studies of the articular cartilage were made.

In the hips which did not undergo osteotomy, radiographs at 26 weeks showed that residual subluxation remained and arthritic changes such as narrowing of the joint space or dislocation were still seen. However, in the operated group there was a remarkable increase in cover, but arthritic changes were not observed. After 24 weeks, the Mankin grading score in the operated group was significantly lower than that in the non-operated group. The latter hips showed an irregular surface of the cartilage, exfoliation and proliferation of synovial tissue. In those undergoing osteotomy, primary cloning of chondrocytes or hypercellularity was seen and at 24 weeks after operation and metaplasia of the cartilage in the fibrous tissue was observed in the boundary between the medial area of the acetabulum and the acetabular fossa.

We hypothesised that meniscal tears treated with mesenchymal stem cells (MSCs) together with a conventional suturing technique would show improved healing compared with those treated by a conventional suturing technique alone. In a controlled laboratory study 28 adult pigs (56 knees) underwent meniscal procedures after the creation of a radial incision to represent a tear. Group 1 (n = 9) had a radial meniscal tear which was left untreated. In group 2 (n = 19) the incision was repaired with sutures and fibrin glue and in group 3, the experimental group (n = 28), treatment was by MSCs, suturing and fibrin glue.

At eight weeks, macroscopic examination of group 1 showed no healing in any specimens. In group 2 no healing was found in 12 specimens and incomplete healing in seven. The experimental group 3 had 21 specimens with complete healing, five with incomplete healing and two with no healing. Between the experimental group and each of the control groups this difference was significant (p < 0.001).

The histological and macroscopic findings showed that the repair of meniscal tears in the avascular zone was significantly improved with MSCs, but that the mechanical properties of the healed menisci remained reduced.

Finite element analysis was used to examine the initial stability after hip resurfacing and the effect of the procedure on the contact mechanics at the articulating surfaces. Models were created with the components positioned anatomically and loaded physiologically through major muscle forces. Total micromovement of less than 10 μm was predicted for the press-fit acetabular components models, much below the 50 μm limit required to encourage osseointegration. Relatively high compressive acetabular and contact stresses were observed in these models. The press-fit procedure showed a moderate influence on the contact mechanics at the bearing surfaces, but produced marked deformation of the acetabular components. No edge contact was predicted for the acetabular components studied.

It is concluded that the frictional compressive stresses generated by the 1 mm to 2 mm interference-fit acetabular components, together with the minimal micromovement, would provide adequate stability for the implant, at least in the immediate post-operative situation.

We studied 51 patients with osteo-articular tuberculosis who were divided into two groups. Group I comprised 31 newly-diagnosed patients who were given first-line antituberculous treatment consisting of isoniazid, rifampicin, ethambutol and pyrazinamide. Group II (non-responders) consisted of 20 patients with a history of clinical non-responsiveness to supervised uninterrupted antituberculous treatment for a minimum of three months or a recurrence of a previous lesion which on clinical observation had healed. No patient in either group was HIV-positive. Group II were treated with an immunomodulation regime of intradermal BCG, oral levamisole and intramuscular diphtheria and tetanus vaccines as an adjunct for eight weeks in addition to antituberculous treatment. We gave antituberculous treatment for a total of 12 to 18 months in both groups and they were followed up for a mean of 30.2 months (24 to 49). A series of 20 healthy blood donors served as a control group.

Twenty-nine (93.6%) of the 31 patients in group I and 14 of the 20 (70%) in group II had a clinicoradiological healing response to treatment by five months.

The CD4 cell count in both groups was depressed at the time of enrolment, with a greater degree of depression in the group-II patients (686 cells/mm³ (sd 261) and 545 cells/mm³ (sd 137), respectively; p < 0.05). After treatment for three months both groups showed significant elevation of the CD4 cell count, reaching a level comparable with the control group. However, the mean CD4 cell count of group II (945 cells/mm³ (sd 343)) still remained lower than that of group I (1071 cells/mm³ (sd 290)), but the difference was not significant. Our study has shown encouraging results after immunomodulation and antituberculous treatment in non-responsive patients. The pattern of change in the CD4 cell count in response to treatment may be a reliable clinical indicator.