Background. Acetabular fractures occur as a result of high-velocity trauma and are often associated with other life threatening injuries. Approximately one-third of these fractures are associated with dislocation of the femoral head but there are only few studies documenting the long term outcomes of this group of acetabular fracture. Methods. This was undertaken at the Royal Infirmary of Edinburgh which provides the definitive orthopaedic treatment for all major trauma including all acetabular fractures for the South East of Scotland. We retrospectively reviewed patients who sustained an acetabular fracture associated with a posterior hip dislocation from a prospectively gathered trauma database between 1990 to 2010. Patient characteristics, complications and the requirement for further surgery were recorded. Patient outcomes were measured using the Oxford Hip score and Short Form SF-12 health survey. Results. A total of 99 patients were treated over a 24 year period. The mean age was 41.3 years. The majority were male (75%). Road traffic accidents were the most common mechanism of injury (47%). The most common Letournal & Judet classification was a posterior wall fracture. Complications such as Sciatic Nerve Palsy was 12.1%, DVT 3%, Infection 5%, Heterotopic ossification 6.1%, Avascular necrosis at 11.1% and 19.2% went on to have a total hip replacement. The mean Oxford Score for Native hip was 34.7 and 31.8 for those who converted to hip replacement. SF12 Physical score was was 40.3 and 39 for the native hips and converted hips respectively. And the SF12 Mental score was 45.5 and 44.9 for the native hips and converted hips respectively. Conclusions. This is the first study to present the long term outcomes following an acetabular fracture dislocation. Our study suggests there is considerable disability in this group of patients and the requirement for subsequent THR has inferior patient reported outcomes. Level of Evidence. Cohort study, Level 2B

Abstract. OBJECTIVES. Hip dislocations remain one of the most common complications of total-hip-arthroplasty (Zahar et al.,2013). There is contradicting evidence whether the surgical approach affects dislocation rates (Sheth et al., 2015; Maratt, 2018). The aim of this study was to develop instrumentation to measure hip forces during simulated range-of-motion tests where the hip was forced to dislocate in cadaveric specimen. METHODS. A total-hip-replacement was completed on both hips of a single cadaveric specimen by a trained orthopaedic surgeon during a lab initiated by DePuy. A direct-anterior surgical approach was performed on the right leg and a posterior approach was performed on the left. Before final implantation of the femoral component, a trial reduction with a femoral neck trial was performed. The neck trial was modified with strain gauges placed around the shaft which were designed to measure resultant hip forces throughout the range-of-motion assessment. A force-calibration was performed using a calibration-block to convert strain to force values. RESULTS. The developed method was able to measure joint forces. Initially the leg was flexed which led to a decrease of joint force for the load component in direction of the neck-axis which was the predominant force during hip dislocation. The leg was subsequently rotated internally which led to a sharp increase with maximum forces of 150N for the direct-anterior approach and 130N for posterior approach. The average absolute calibration error was 6.7%. CONCLUSIONS. The peak force in neck direction was slightly higher for the direct-anterior approach compared to the posterior approach which indicates that the soft tissue tension was potentially higher. Limitations of this study were potentially lower soft tissue tension of cadaveric specimens, the sample size and low calibration accuracy. Component position was not assessed, which is another significant contributor to joint stability. However, the data will be useful for enhanced understanding of dislocation mechanisms. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Abstract. OBJECTIVES. Dual mobility (DM) total hip replacements (THRs) were introduced to reduce the risk of hip dislocation in at-risk patients. DM THRs have shown good overall survivorship and low rates of dislocation, however, the mechanisms which describe how these bearings function in-vivo are not fully understood. This is partly due to a lack of suitable characterisation methodologies which are appropriate for the novel geometry and function of DM polyethylene liners, whereby both surfaces are subject to articulation. This study aimed to develop a novel semi-quantitative geometric characterisation methodology to assess the wear/deformation of DM liners. METHODS. Three-dimensional coordinate data of the internal and external surfaces of 14 in-vitro tested DM liners was collected using a Legex 322 coordinate measuring machine. Data was input into a custom Matlab script, whereby the unworn reference geometry was determined using a sphere fitting algorithm. The analysis method determined the geometric variance of each point from the reference surface and produced surface deviation heatmaps to visualise areas of wear/deformation. Repeatability of the method was also assessed. RESULTS. Semi-quantitative analysis of the surface deviation heatmaps revealed circumferential damage patterns similar to those reported in the literature. Additionally, the location of the damaged regions corresponded between the internal and external surfaces. Comparing five repeat measurements of the same liner, the maximum geometric variance of each surface varied by 1 µm (standard deviation) suggesting a high repeatability of the method. CONCLUSIONS. This study presents an effective and highly repeatable characterisation methodology to semi-quantitatively assess the wear/deformation of in-vitro tested DM liners. This method is suitable for the analysis of retrieved DM liners whereby no pre-service information is available, which may provide information about the complex in-vivo kinematics and mechanical failure mechanisms of these bearings

Abstract. Objectives. Outcomes following different types of surgical intervention for FAI are well reported individually but comparative data is deficient. The purpose of this study was to conduct a systematic review (SR) and meta-analysis to analyse the outcomes following surgical management of FAI by hip arthroscopy (HA), anterior mini open approach (AMO) and surgical hip dislocation (SHD). Methods. This SR was registered with PROSPERO. An electronic database search of Pubmed, Medline and EMBASE for English and German language articles over the last 20 years was carried out according to the PRISMA guidelines. We specifically analysed and compared changes in patient reported outcome measures PROMs, α-angle, rate of complications, rate of revision and conversion to total hip arthroplasty (THA). Results. A total of 48 articles included for final analysis with a total of 4384 hips in 4094 patients. All subgroups showed a significant correction in mean alpha angle post-operatively with a mean change of 28.8° (95% CI, 21°-36.5°; p <0.01) after AMO, 21.1° (95% CI, 15.1°-27°; p <0.01) after SHD and 20.39° (95% CI, 15.66°-25.12°; p <0.01) after HA. AMO group showed a significantly higher increase in PROMs (3.7; 95% CI, 3.2–4.2; p <0.01) versus arthroscopy (2.47; 95% CI, 2.22–2.73; p <0.01) and SHD (2.4; 95% CI, 1.5–3.3; p <0.01). However, the rate of complications following AMO was significantly higher than HA and SHD. Conclusion. All three surgical approaches offered significant improvements in outcomes and radiological correction of cam deformities. All three groups showed similar rates of revision procedures and SHD had the highest rate of conversion to a THA. Revision rates was similar for all three revision procedures

Introduction and Objective. Heterotopic ossification is the formation of extraskeletal mineralized tissue commonly associated with either trauma or surgery. While several mouse models have been developed to better characterize the pathologic progression of HO, no model currently exists to study HO of the hip, the most common location of acquired HO in patients. Owing to the unique biological mechanisms underpinning the formation of HO in different tissues, we sought to develop a model to study the post-surgical HO of the hip. Materials and Methods. Wild-type mice C57BL/6J mice were used to study the procedure outcomes, while Pdgfra-CreERT2;mT/mG and Scx-GFP reporter animals were used for the lineage tracing experiments (total n=16 animals, male, 12 weeks old). An anterolateral approach to the hip was performed. Briefly, a 2 cm incision was made centered on the great trochanter and directed proximal to the iliac crest and distally over the lateral shaft of the femur. The joint was then reached following the intermuscular plane between the rectus femoris and gluteus medius muscles. After the joint was exposed, the articular cartilage was removed using a micropower drill with a 1.2 mm reamer. The medius gluteus and superficial fascia were then re-approximated with Vicryl 5-0 suture (Ethicon Inc, Somerville, NJ) and skin was then closed with Ethilon 5-0 suture (Ethicon Inc). Live high resolution XR imaging was performed every 2 wks to assess the skeletal tissues (Faxitron Bioptics, Tucson, AZ). The images were then scored using the Brooker classification. Ex-vivo microCT was conducted using a Skyscan 1275 scanner (Bruker-MicroCT, Kontich, Belgium). 3D reconstruction and analysis was performed using Dragonfly (ORS Inc., Montreal, Canada). For the histological analysis of specimens, Hematoxylin and Eosin (H&E), modified Goldner's Trichrome (GMT) stainings were performed. Reporter activity was assessed using fluorescent imaging. Results. Substantial periarticular heterotopic bone was seen in all cases. A periosteal reaction and an initial formation of calcified tissue within the soft tissue was apparent starting from 4 wks after surgery. By XR, progressive bone formation was observed within the periosteum and intermuscular planes during the subsequent 8 weeks. Stage 1 HO was observed in 12.5% of cases, stage 2 in 62.5% of cases, and stage 3 HO in 25% of cases. 3D microCT reconstructions of the treated hip joints demonstrated significant de novo heterotopic bone in several location which phenocopy human disease. Heterotopic bone was observed in an intracapsular location, periosteal location involving the iliac bone and proximal femur, and intermuscular locations. Histological analyses further confirmed these findings. To assess the cells which gave rise to HO in this model, an inducible PDGFRα and constitutive Scx-GFP reporter mice were used. A dramatic increase in mGFP reporter activity was noted PDGFRα within the HO injury site, including in areas of new cartilage and bone formation. Scx-associated reporter activity increased in the soft tissue and periosteal periacetabular areas of injured hips. Conclusions. HO has a diverse set of pathologies, of which joint associated HO after elective surgery is the most common. Here, we present the first mouse model of hip dislocation and acetabular reaming that mimics elements of human periarticular HO. The diverse locations of HO after acetabular reaming (intracapsular, intermuscular and periosteal) suggests the activation of different and specific HO program after surgery. Such a field effect would be consistent with local trauma and inflammation, which is a well-studied contributor to HO genesis. Not surprisingly, joint-associated HO significantly derives from PDGFRα-expressing cells, which has been shown to similarly give rise to intramuscular and intratendinous HO

Reported rates of dislocation in hip hemiarthroplasty (HA) for the treatment of intra-capsular fractures of the hip, range between 1% and 10%. HA is frequently performed through a direct lateral surgical approach. The aim of this study is to determine the contribution of the anterior capsule to the stability of a cemented HA through a direct lateral approach. . A total of five whole-body cadavers were thawed at room temperature, providing ten hip joints for investigation. A Thompson HA was cemented in place via a direct lateral approach. The cadavers were then positioned supine, both knee joints were disarticulated and a digital torque wrench was attached to the femur using a circular frame with three half pins. The wrench applied an external rotation force with the hip in extension to allow the hip to dislocate anteriorly. Each hip was dislocated twice; once with a capsular repair and once without repairing the capsule. Stratified sampling ensured the order in which this was performed was alternated for the paired hips on each cadaver. . Comparing peak torque force in hips with the capsule repaired and peak torque force in hips without repair of the capsule, revealed a significant difference between the ‘capsule repaired’ (mean 22.96 Nm, standard deviation (. sd. ) 4.61) and the ‘capsule not repaired’ group (mean 5.6 Nm, . sd. 2.81) (p < 0.001). Capsular repair may help reduce the risk of hip dislocation following HA. Cite this article: Bone Joint J 2015;97-B:141–4

Posterior soft tissue repair is often performed in Total Hip Arthroplasty (THA). Many reports have shown the advantage of posterior soft tissue repair in reducing their prosthetic hip dislocation rates. We describe an easy and inexpensive way of passing sutures through small drill holes in the Greater Trocanter to re-attach muscle, tendon and capsule in a posterior soft tissue repair. By using a reversed monofilament suture on a straight needle held in artery forceps and passing this in a retrograde direction through a drill hole, a suture capturing device is produced. By capturing the long ends of sutures tied in the short external rotators and the posterior capsule of the hip through 2 drill holes in the Greater Trochanter, a posterior soft tissue repair can be performed. We have used this technique successfully in over 100 consecutive THAs. We conclude that the use of a monofilament suture used in the manner describe is an excellent and inexpensive way to aid in a posterior soft tissue repair in THAs. This is done without the cost of an additional dedicated suture passing device. The suture could also be used in the skin closure if desired

Femoral neck fractures remain the leading cause of early failure after metal-on-metal hip resurfacing. Although its' exact pathomechanism has yet to be fully elucidated, current retrieval analysis has shown that either an osteonecrotic event and/or significant surgical trauma to the femoral head neck junction are the leading causes. It is most likely that no single factor like patient selection and/or femoral component orientation can fully avoid their occurrence. As in osteonecrosis of the native hip joint, a certain cell injury threshold may have to be reached in order for femoral neck fracture to occur. These insults are not limited to the surgical approach, but also include femoral head preparation, neck notching, and cement penetration. Although some have argued that the posterior approach does not represent an increased risk fracture for ON after hip resurfacing because of the so-called intraosseous blood supply to the femoral head, to date, the current body of literature on femoral head blood flow in the presence of arthritis has confirmed the critical role of the extraosseous blood supply from the ascending branch of the medial circumflex, as well as the lack of any substantial intraosseous blood supply. Conversely, anterior hip dislocation of both the native hip joint as well as the arthritic hip preserves femoral head vascularity. The blood supply can be compromised by either sacrificing the main branch of the ascending medial femoral circumflex artery or damaging the retinacular vessels at the femoral head-neck junction. Thus an approach which preserves head vascularity, while minimizing soft tissue disruption would certainly be favorable for hip resurfacing. This presentation will review the current state of knowledge on vascularity of the femoral head as well as surgical techniques enhancing its preservation

In order to evaluate the relationship between acetabular and proximal femoral alignment in the initiation and evolution of osteoarthritis of the dysplastic hip, the acetabular and femoral angles were calculated geometrically from radiographs of 62 patients with pre-arthrosis and early osteoarthritis. The sum of the lateral opening angle of the acetabulum and the neck-shaft angle was defined as the lateral instability index (LII), and the sum of the anterior opening angle of the acetabulum and the anteversion angle of the femoral neck as the anterior instability index (AII). These two indices were compared in dysplastic and unaffected hips. A total of 22 unilateral hips with pre-arthrosis were followed for at least 15 years to determine whether the two indices were associated with the progression of osteoarthritis.

The LII of the affected hips (197.4 (sd 6.0)) was significantly greater than that of the unaffected hips (1830 (sd 6.9)). A follow-up study of 22 hips with pre-arthrosis showed that only the LII was associated with progression of the disease, and an LII of 196 was the threshold value for this progression.