Introduction: Shortening of the affected limb has frequently been observed in children with Legg-Calvé-Perthes disease (LCPD). Many factors have been thought as the cause of this residual shortening after LCPD. There has been no clear answer regarding which is more responsible for the residual shortening between coxa plana and the disturbed physeal growth. To clarify the main cause of residual shortening, clinical and experimental studies were conducted.

Materials and Methods: For clinical study, 40 LCPD children with definite shortening were evaluated. This included 20 children with active disease and 20 children at skeletal maturity. Teleoroentgenograms were obtained for all children. For the experimental study, LCPD simulation in 30 piglets was achieved by disrupting the blood supply to the capital femoral epiphysis.

Results: In the clinical study, total shortening in the skeletal maturity group was 14.6 mm, which consisted of 3.2 mm (16%) shortening by decreased epiphyseal height and 11.5 mm (84%) shortening by physeal growth disturbance. Total shortening in the active disease group was 7.9 mm, which consisted of 6.4 mm (84%) decrease of epiphyseal height and 1.5 mm (16%) shortening by physeal growth disturbance. In the experimental study, overall shortening (13.6 mm) in the piglet model showed a predominance of disturbed physeal growth. The proportions were 3.2 mm (24%) by epiphyseal height decrease and 10.4 mm (76%) by physeal growth disturbance.

Conclusion: Physeal growth disturbance was mostly responsible for the residual shortening following LCPD. However, in the stages of active disease, the shortening of the extremity was mainly caused by a decrease of epiphyseal height.

In clinical studies of cemented total hip arthroplasty (THA), polished stems produce less slippage at the bone-cement interface than roughened stems. Our objective is to assess the effect of stem-cement debonding on the bone-cement interface shear behaviour of hip implants using simplified axisymmetric stem-cement-aluminum models.

We emulated the femoral stems using stainless steel tapered plugs with either a rough (i.e. bonded) or smooth (i.e. unbonded) surface finish. Three different taper angles (5°, 7.5°, 10°) were used for the unbonded constructs. Non-tapered and tapered (7.5°) aluminum shells were used to emulate the diaphyseal and metaphyseal segments of the femur. In all cases, the cement-aluminum interface was designed to have the same shear strength as has been reported for bone-cement interfaces (~8 MPa). The test involved applying axial compressive loading at a rate of 0.02 mm/s until failure. Six specimens were tested for each combination of the parameters.

The unbonded stems sustained about twice as much load as the bonded stem, regardless of taper angle, and the metaphyseal model carried 35-50% greater loads than the diaphyseal models before shear failure or slippage. The unbonded constructs reached peak load with excessive displacement due to creep of the cement mantle while the bonded constructs failed in shear at the cement-aluminum interface. This result supports the hypothesis that the wedging forces created in the unbonded construct increase the compression forces across the aluminum-cement interface, thereby increasing its shear resistance. A finite element analysis predicted that the cement could withstand the hoop stress under these loading circumstances and this prediction was confirmed by visual inspection of the cement after each test.

Our results suggest that smooth or unbonded stems should sustain less slippage and shear damage at the bone-cement interface than roughened or bonded stems due to the wedge-induced compressive stress; this increased load capacity will be particularly valuable when the condition of the bone-cement interface is suboptimal.

Purpose: To introduce modified tibial inlay technique for autogenous bone-patellar tendon-bone (BPTB) posterior cruciate ligament (PCL) reconstruction and evaluate the outcomes of PCL reconstruction by this method.

Methods: Fifty patients who underwent autogenous BPTB PCL reconstruction using modified tibial inlay technique were evaluated at average 30.9 months (range 12–52).

The outcomes were assessed by stress radiographs, maximal manual test with KT-2000 arthrometer, IKDC grading and OAK knee score.

Results: Average side to side difference in push view with Telos stress device decreased from 11.7mm to 3.2mm. Difference in maximal manual test with KT-2000 arthrometer also decreased from 11.5mm to 3.1mm. Final IKDC grading was A in six patients, B in thirty four, C in nine and D in one.

Average OAK score improved from 64.3 to 86.4

Conclusion: We consider that the modified tibial inlay technique is a method to reduce technical effort and contribute to satisfactory clinical results in autogenous BPTB PCL reconstruction.

We reviewed retrospectively the role of monitoring of somatosensory spinal evoked potentials (SSEP) in 99 patients with neuromuscular scoliosis who had had operative correction with Luque-Galveston rods and sublaminar wiring.

Our findings showed that SSEP monitoring was useful and that a 50% decrease in the amplitude of the trace optimised both sensitivity and specificity. The detection of true-positive results was higher than in cases of idiopathic scoliosis, but the method was less sensitive and specific and there were more false-negative results. In contrast with the findings in idiopathic scoliosis, recovery of the trace was associated with a 50% to 60% risk of neurological impairment.

Only one permanent injury occurred during the use of this technique, and any temporary impairment resolved within two months.

Reports of differing failure rates of total hip prostheses made of various metals prompted us to measure the size of metallic and polyethylene particulate debris around failed cemented arthroplasties. We used an isolation method, in which metallic debris was extracted from the tissues, and a non-isolation method of routine preparation for light and electron microscopy. Specimens were taken from 30 cases in which the femoral component was of titanium alloy (10), cobalt-chrome alloy (10), or stainless steel (10). The mean size of metallic particles with the isolation method was 0.8 to 1.0 microns by 1.5 to 1.8 microns. The non-isolation method gave a significantly smaller mean size of 0.3 to 0.4 microns by 0.6 to 0.7 microns. For each technique the particle sizes of the three metals were similar. The mean size of polyethylene particles was 2 to 4 microns by 8 to 13 microns. They were larger in tissue retrieved from failed titanium-alloy implants than from cobalt-chrome and stainless-steel implants. Our results suggest that factors other than the size of the metal particles, such as the constituents of the alloy, and the amount and speed of generation of debris, may be more important in the failure of hip replacements.

We studied the healing and torsional strength of non-vascularised (28) and vascularised (28) sections of tibial diaphyses in 56 cats. Both types of graft achieved fracture union in the same period of time, and at 12 and 16 weeks the non-vascularised grafts were as strong as the vascularised grafts.