Comparison of distal and proximal centralising devices in hip arthroplasty

Centralising devices were introduced to ensure that the prosthesis is implanted in a neutral position and that a cement mantle of optimal thickness is achieved proximally and distally. A distal centralising device (DCD) is compared with a proximal midshaft centralising device (PCD) to test which one provides a more neutral prosthetic alignment. Thirty consecutive patients undergoing hemiarthroplasties for femoral neck fractures were studied prospectively. Patients were blindly randomised to receive either a femoral component with proximal midshaft centraliser or distal centraliser. Both components were implanted following the manufacturer’s protocol. Postoperative true anteroposterior and lateral radiographs were made to assess the stem position. There was no statistically significant difference between the two groups in zones 1, 2, 3, 4, 5, 6 and 7 in both anteroposterior and lateral radiographic measurements. DCP and PCD both have similar centralisation and cement mantle. Future studies should be done to evaluate their long-term effect

Perception of affordances for vertical and horizontal jumping in children: gymnasts versus non-athletes

WOS:000563354000001 PubMed ID: 32853118Purpose: We investigated the perception of affordances for vertical jumping-and-reaching and horizontal jumping by children.Method: In the horizontal task, children were asked to judge their ability in the standing long jump. In the vertical task, children were asked to judge the height of a ball that they could run to, jump up, and reach with their fingertips. Following judgments, children performed both types of jumps. We compared gymnasts (children with at least 2 years of gymnastics training; 7.92 +/- 0.91 years) versus children with no competitive athletic experience (7.74 +/- 0.86 years).Results: As expected, actual ability was greater in gymnasts than in non-athletes, for both types of jump (eachp< .001). We separately analyzed Constant Error and Absolute Error of judgments (relative to actual performance). Results revealed that gymnasts tended toward underestimation, while non-athletes tended toward overestimation. Absolute error differed between tasks for the non-athletes (p< .001), but for the gymnasts the difference between conditions was not significant (p= .25). Absolute error differed between groups for vertical jump-and-reach (p< .01) but not for horizonal jump (p= .17).Conclusions: Gymnastics experience was associated with a generalized tendency for children to underestimate their jumping ability. In addition, gymnastics experience was associated with judgment accuracy that was consistent across tasks. The results reveal that gymnastics training is associated with changes in athletic ability, but also with changes in the perception of affordances

Lengthening of short bones by distraction osteogenesis—results and complications

We performed bone lengthening surgery on 12 metacarpals and 14 metatarsals of 15 patients. The mean age for metacarpal and metatarsal lengthening was 14.5 (10–21) and 17.5 (10–25) years, respectively. We used a unilateral or a circular external fixator. The mean healing index of the metacarpals and metatarsals was 1.6 (1.1–2.3) and 1.6 (1.0–2.0) months/cm, respectively. The mean increase in metacarpal and metatarsal length was 17.6 (13–26) and 24.3 (20–30) mm, respectively. The functional scores of the metatarso-phalangial (MTP) joint of lengthened metatarsals for the lesser toe were excellent in 12 and good in two cases based on the American Orthopaedic Foot and Ankle Society (AOFAS) scoring system. Complications were seen in six of the metatarsal lengthening cases including four angulations, one subluxation and one non-union. We conclude that the periosteum must be protected with percutaneous osteotomy and lengthening should be performed at a rate of 0.25 mm twice a day and should not exceed 40% of the original bone length (or >20 mm)