Aims

The pelvis rotates in the sagittal plane during daily activities. These rotations have a direct effect on the functional orientation of the acetabulum. The aim of this study was to quantify changes in pelvic tilt between different functional positions.

The aim of this study was to assess the effect of frictional torque and bending moment on fretting corrosion at the taper interface of a modular femoral component and to investigate whether different combinations of material also had an effect. The combinations we examined were 1) cobalt–chromium (CoCr) heads on CoCr stems 2) CoCr heads on titanium alloy (Ti) stems and 3) ceramic heads on CoCr stems.

In test 1 increasing torque was imposed by offsetting the stem in the anteroposterior plane in increments of 0 mm, 4 mm, 6 mm and 8 mm when the torque generated was equivalent to 0 Nm, 9 Nm, 14 Nm and 18 Nm.

In test 2 we investigated the effect of increasing the bending moment by offsetting the application of axial load from the midline in the mediolateral plane. Increments of offset equivalent to head + 0 mm, head + 7 mm and head + 14 mm were used.

Significantly higher currents and amplitudes were seen with increasing torque for all combinations of material. However, Ti stems showed the highest corrosion currents. Increased bending moments associated with using larger offset heads produced more corrosion: Ti stems generally performed worse than CoCr stems. Using ceramic heads did not prevent corrosion, but reduced it significantly in all loading configurations.

Cite this article: Bone Joint J 2015;97-B:463–72.

The use of large-diameter metal-on-metal (MoM) components in total hip arthroplasty (THA) is associated with an increased risk of early failure due to adverse local tissue reaction to metal debris (ARMD) in response to the release of metal ions from the bearing couple and/or head-neck taper corrosion. The aim of this paper was to present a review of the incidence and natural history of ARMD and the forms of treatment, with a focus on the need for and extent of resection or debulking of the pseudotumour. An illustrative case report is presented of a patient with an intra-pelvic pseudotumour associated with a large diameter MoM THA, which was treated successfully with revision of the bearing surface to a dual mobility couple and retention of the well-fixed acetabular and femoral components. The pseudotumour was left in situ. Resolution of the intra-pelvic mass and normalisation of metal ion levels was observed seven months post-operatively.

Cite this article: Bone Joint J 2016;98-B:736–40.

Aims

We carried out a further study of the long-term results of the cemented Exeter femoral component in patients under the age of 40 with a mean follow-up of 13.6 years (10 to 20).

We describe our experience in the reduction of dislocation of the hip secondary to developmental dysplasia using ultrasound-guided gradual reduction using flexion and abduction continuous traction (FACT-R). During a period of 13 years we treated 208 Suzuki type B or C complete dislocations of the hip in 202 children with a mean age of four months (0 to 11). The mean follow-up was 9.1 years (five to 16). The rate of reduction was 99.0%. There were no recurrent dislocations, and the rate of avascular necrosis of the femoral head was 1.0%. The rate of secondary surgery for residual acetabular dysplasia was 19.2%, and this was significantly higher in those children in whom the initial treatment was delayed or if other previous treatments had failed (p = 0.00045). The duration of FACT-R was significantly longer in severe dislocations (p = 0.001) or if previous treatments had failed (p = 0.018).

This new method of treatment is effective and safe in these difficult cases and offers outcomes comparable to or better than those of standard methods.

Cite this article: Bone Joint J 2015;97-B:405–11.

Objectives

Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA.

Successful management of late presenting hip dislocation in childhood is judged by the outcome not just at skeletal maturity but well beyond into adulthood and late middle age. This review considers different methods of treatment and looks critically at the handful of studies reporting long-term follow-up after successful reduction.

Cite this article: Bone Joint J 2015;97-B:729–33.

Aims

The aim of this study was to inform a definitive trial which could determine the clinical effectiveness of the X-Bolt Dynamic Hip Plating System compared with the sliding hip screw for patients with complex pertrochanteric fragility fractures of the femur.

When fracture of an extensively porous-coated femoral component occurs, its removal at revision total hip arthroplasty (THA) may require a femoral osteotomy and the use of a trephine. The remaining cortical bone after using the trephine may develop thermally induced necrosis. A retrospective review identified 11 fractured, well-fixed, uncemented, extensively porous-coated femoral components requiring removal using a trephine with a minimum of two years of follow-up.

The mean time to failure was 4.6 years (1.7 to 9.1, standard deviation (sd) 2.3). These were revised using a larger extensively porous coated component, fluted tapered modular component, a proximally coated modular component, or a proximal femoral replacement. The mean clinical follow-up after revision THA was 4.9 years (2 to 22, sd 3.1). The mean diameter of the femoral component increased from 12.7 mm (sd 1.9) to 16.2 mm (sd 3.4; p >  0.001). Two revision components had radiographic evidence of subsidence that remained radiographically stable at final follow-up. The most common post-operative complication was instability affecting six patients (54.5%) on at least one occasion.

A total of four patients (36.4%) required further revision: three for instability and one for fracture of the revision component. There was no statistically significant difference in the mean Harris hip score before implant fracture (82.4; sd 18.3) and after trephine removal and revision THA (81.2; sd 14.8, p = 0.918).

These findings suggest that removal of a fractured, well-fixed, uncemented, extensively porous-coated femoral component using a trephine does not compromise subsequent fixation at revision THA and the patient’s pre-operative level of function can be restored. However, the loss of proximal bone stock before revision may be associated with a high rate of dislocation post-operatively.

Cite this article: Bone Joint J 2015;97-B:1192–6.

Fresh-frozen allograft bone is frequently used in orthopaedic surgery. We investigated the incidence of allograft-related infection and analysed the outcomes of recipients of bacterial culture-positive allografts from our single-institute bone bank during bone transplantation. The fresh-frozen allografts were harvested in a strict sterile environment during total joint arthroplasty surgery and immediately stored in a freezer at -78º to -68º C after packing. Between January 2007 and December 2012, 2024 patients received 2083 allografts with a minimum of 12 months of follow-up. The overall allograft-associated infection rate was 1.2% (24/2024). Swab cultures of 2083 allografts taken before implantation revealed 21 (1.0%) positive findings. The 21 recipients were given various antibiotics at the individual orthopaedic surgeon’s discretion. At the latest follow-up, none of these 21 recipients displayed clinical signs of infection following treatment. Based on these findings, we conclude that an incidental positive culture finding for allografts does not correlate with subsequent surgical site infection. Additional prolonged post-operative antibiotic therapy may not be necessary for recipients of fresh-frozen bone allograft with positive culture findings.

Cite this article: Bone Joint J 2015;97-B:427–31.

Objective

Hip arthroscopy in the setting of hip dysplasia is controversial in the orthopaedic community, as the outcome literature has been variable and inconclusive. We hypothesise that outcomes of hip arthroscopy may be diminished in the setting of hip dysplasia, but outcomes may be acceptable in milder or borderline cases of hip dysplasia.

Aims

It has been suggested that cemented fixation of total hip arthroplasty (THA) is associated with an increased peri-operative mortality compared with cementless THA. Our aim was to investigate this through a nationwide matched cohort study adjusting for age, comorbidity, and socioeconomic background.

Aim

Until now, there has been no consensus as to whether stemmed acetabular components are appropriate for use in patients undergoing revision total hip arthroplasty (THA) who have major acetabular defects or pelvic discontinuity. We wished to address this deficiency in the literature.

Aims

The optimal treatment for independent patients with a displaced intracapsular fracture of the hip remains controversial. The recognised alternatives are hemiarthroplasty and total hip arthroplasty. At present there is no established standard of care, with both types of arthroplasty being used in many centres.

The purpose of this study was to determine patient-reported outcomes of patients with mild to moderate developmental dysplasia of the hip (DDH) and femoroacetabular impingement (FAI) undergoing arthroscopy of the hip in the treatment of chondrolabral pathology. A total of 28 patients with a centre-edge angle between 15° and 19° were identified from an institutional database. Their mean age was 34 years (18 to 53), with 12 female and 16 male patients. All underwent labral treatment and concomitant correction of FAI. There were nine reoperations, with two patients requiring revision arthroscopy, two requiring periacetabular osteotomy and five needing total hip arthroplasty.

Patients who required further major surgery were more likely to be older, male, and to have more severe DDH with a larger alpha angle and decreased joint space.

At a mean follow-up of 42 months (24 to 89), the mean modified Harris hip score improved from 59 (20 to 98) to 82 (45 to 100; p < 0.001). The mean Western Ontario and McMaster Universities Osteoarthritis Index score improved from 30 (1 to 61) to 16 (0 to 43; p < 0.001). Median patient satisfaction was 9.0/10 (1 to 10). Patients reported excellent improvement in function following arthroscopy of the hip.

This study shows that with proper patient selection, arthroscopy of the hip can be successful in the young patient with mild to moderate DDH and FAI.

Cite this article: Bone Joint J 2015;97-B:1316–21.

Aims

The purpose of this retrospective study was to differentiate between the MRI features of normal post-operative change and those of residual or recurrent disease after intralesional treatment of an atypical cartilage tumour (ACT)/grade I chondrosarcoma.

Aims

The aim of the study was to develop a quantitative scoring system to predict whether a large-to-massive rotator cuff tear was arthroscopically reparable prior to surgery.

In this study we used subject-specific finite element analysis to investigate the mechanical effects of rotational acetabular osteotomy (RAO) on the hip joint and analysed the correlation between various radiological measurements and mechanical stress in the hip joint.

We evaluated 13 hips in 12 patients (two men and ten women, mean age at surgery 32.0 years; 19 to 46) with developmental dysplasia of the hip (DDH) who were treated by RAO.

Subject-specific finite element models were constructed from CT data. The centre–edge (CE) angle, acetabular head index (AHI), acetabular angle and acetabular roof angle (ARA) were measured on anteroposterior pelvic radiographs taken before and after RAO. The relationship between equivalent stress in the hip joint and radiological measurements was analysed.

The equivalent stress in the acetabulum decreased from 4.1 MPa (2.7 to 6.5) pre-operatively to 2.8 MPa (1.8 to 3.6) post-operatively (p < 0.01). There was a moderate correlation between equivalent stress in the acetabulum and the radiological measurements: CE angle (R = –0.645, p < 0.01); AHI (R = –0.603, p < 0.01); acetabular angle (R = 0.484, p = 0.02); and ARA (R = 0.572, p < 0.01).

The equivalent stress in the acetabulum of patients with DDH decreased after RAO. Correction of the CE angle, AHI and ARA was considered to be important in reducing the mechanical stress in the hip joint.

Cite this article: Bone Joint J 2015;97-B:492–7.

In this in vitro study of the hip joint we examined which soft tissues act as primary and secondary passive rotational restraints when the hip joint is functionally loaded. A total of nine cadaveric left hips were mounted in a testing rig that allowed the application of forces, torques and rotations in all six degrees of freedom. The hip was rotated throughout a complete range of movement (ROM) and the contributions of the iliofemoral (medial and lateral arms), pubofemoral and ischiofemoral ligaments and the ligamentum teres to rotational restraint was determined by resecting a ligament and measuring the reduced torque required to achieve the same angular position as before resection. The contribution from the acetabular labrum was also measured. Each of the capsular ligaments acted as the primary hip rotation restraint somewhere within the complete ROM, and the ligamentum teres acted as a secondary restraint in high flexion, adduction and external rotation. The iliofemoral lateral arm and the ischiofemoral ligaments were primary restraints in two-thirds of the positions tested. Appreciation of the importance of these structures in preventing excessive hip rotation and subsequent impingement/instability may be relevant for surgeons undertaking both hip joint preserving surgery and hip arthroplasty.

Cite this article: Bone Joint J 2015; 97-B:484–91.