The ability to predict load-bearing capacity during the consolidation phase in distraction osteogenesis by non-invasive means would represent a significant advance in the management of patients undergoing such treatment. Measurements of stiffness have been suggested as a promising tool for this purpose. Although the multidimensional characteristics of bone loading in compression, bending and torsion are apparent, most previous experiments have analysed only the relationship between maximum load-bearing capacity and a single type of stiffness. We have studied how compressive, bending and torsional stiffness are related to the torsional load-bearing capacity of healing callus using a common set of samples of bone regenerate from 26 sheep treated by tibial distraction osteogenesis.

Our findings showed that measurements of torsional, bending and compressive stiffness were all suitable as predictors of the load-bearing capacity of healing callus. Measurements of torsional stiffness performed slightly better than those of compressive and bending stiffness.

Limited access surgery is thought to reduce post-operative morbidity and provide faster recovery of function. The percutaneous compression plate (PCCP) is a recently introduced device for the fixation of intertrochanteric fractures with minimal exposure. It has several potential mechanical advantages over the conventional compression hip screw (CHS). Our aim in this prospective, randomised, controlled study was to compare the outcome of patients operated on using these two devices.

We randomised 104 patients with intertrochanteric fractures (AO/OTA 31.A1–A2) to surgical treatment with either the PCCP or CHS and followed them for one year postoperatively.

The mean operating blood loss was 161.0 ml (8 to 450) in the PCCP group and 374.0 ml (11 to 980) in the CHS group (Student’s t-test, p < 0.0001). The pain score and ability to bear weight were significantly better in the PCCP group at six weeks post-operatively. Analysis of the radiographs in a proportion of the patients revealed a reduced amount of medial displacement in the PCCP group (two patients, 4%) compared with the CHS group (10 patients, 18.9%); Fisher’s exact test, p < 0.02.

The PCCP device was associated with reduced intra-operative blood loss, less postoperative pain and a reduced incidence of collapse of the fracture.

Critical size defects in ovine tibiae, stabilised with intramedullary interlocking nails, were used to assess whether the addition of carboxymethylcellulose to the standard osteogenic protein-1 (OP-1/BMP-7) implant would affect the implant’s efficacy for bone regeneration. The biomaterial carriers were a ‘putty’ carrier of carboxymethylcellulose and bovine-derived type-I collagen (OPP) or the standard with collagen alone (OPC). These two treatments were also compared to “ungrafted” negative controls. Efficacy of regeneration was determined using radiological, biomechanical and histological evaluations after four months of healing. The defects, filled with OPP and OPC, demonstrated radiodense material spanning the defect after one month of healing, with radiographic evidence of recorticalisation and remodelling by two months. The OPP and OPC treatment groups had equivalent structural and material properties that were significantly greater than those in the ungrafted controls. The structural properties of the OPP- and OPC-treated limbs were equivalent to those of the contralateral untreated limb (p > 0.05), yet material properties were inferior (p < 0.05). Histopathology revealed no residual inflammatory response to the biomaterial carriers or OP-1. The OPP- and OPC-treated animals had 60% to 85% lamellar bone within the defect, and less than 25% of the regenerate was composed of fibrous tissue. The defects in the untreated control animals contained less than 40% lamellar bone and more than 60% was fibrous tissue, creating full cortical thickness defects. In our studies carboxymethylcellulose did not adversely affect the capacity of the standard OP-1 implant for regenerating bone.

The tensile strength of the medial patellofemoral ligament (MPFL), and of surgical procedures which reconstitute it, are unknown. Ten fresh cadaver knees were prepared by isolating the patella, leaving only the MPFL as its attachment to the medial femoral condyle. The MPFL was either repaired by using a Kessler suture or reconstructed using either bone anchors or one of two tendon grafting techniques. The tensile strength and the displacement to peak force of the MPFL were then measured using an Instron materials-testing machine.

The MPFL was found to have a mean tensile strength of 208 N (SD 90) at 26 mm (SD 7) of displacement. The strengths of the other techniques were: sutures alone, 37 N (SD 27); bone anchors plus sutures, 142 N (SD 39); blind-tunnel tendon graft, 126 N (SD 21); and through-tunnel tendon graft, 195 N (SD 66). The last was not significantly weaker than the MPFL itself.

We present the outcome of 47 Souter-Strathclyde replacements of the elbow with a mean follow-up of 82 months (12 to 129). The clinical results were assessed using a condition-specific outcome measure. The mean total score (maximum 100) before the operation was 47.21 and improved to 79.92 (p < 0.001). The mean pain score (maximum 50) improved from 21.41 to 46.70 (p < 0.001) and the mean functional component of the score (maximum 30) from 11.19 to 18.65 (p < 0.001). There was negligible change in the score for the range of movement although a significant improvement in mean flexion from 124° to 136° was noted (p < 0.001).

Revision surgery was required in four patients, for dislocation, wound dehiscence and early infection in one, late infection in two and aseptic loosening in one. The cumulative survival was 75% at nine years for all causes of failure and 97% at ten years for aseptic loosening alone. Our study demonstrates the value of the Souter-Strathclyde total elbow arthroplasty in providing relief from pain and functional improvement in rheumatoid patients.

We investigated the changes in surface roughness of retrieved femoral components in 18 men and four women at revision knee surgery. The mean age at revision was 68.4 years and the mean period of implantation was for 55.6 months. Eighteen implants were retrieved for aseptic loosening and four for infection. The surface changes in the articulating areas were inspected visually and the roughness (Ra) analysed with a profilometer. Parallel scratching and burnishing were the two main forms of damage. The mean Ra measurements in the articulating areas showed no statistically significant difference when compared with those in a control area on either side of the patellar groove at the apex of the femoral flange. This suggests that it is not essential to revise a well-fixed and correctly aligned femoral component where the polished surface has become burnished or bears fine parallel scratches, if the revision is conducted solely for failure of the tibial component.