At six weeks and three months, KT-1000 side-to-side differences between the groups are not statistically significant (student-t test, p=0.87 and p=0.34, respectively). In clinical results at six months, tibial fixation with Bioscrew XtraLok has significantly decreased laxity compared to the Intrafix device (p=0.017). This prospective, randomized clinical comparison of tibial fixation in hamstring ACL reconstruction evaluated mechanical results (laxity) between BioScrew XtraLok® (Linvatec, Largo, FL) and Intrafix® (Mitek Products, Norwood, MA) at six months. After Ethics Review Board approval and sample-size calculation, one hundred and three sequential patients undergoing ACL reconstruction were recruited. Inclusion criteria were: absence of other ligamentous injury or previous knee surgery, and a normal contralateral knee. After drilling tunnels, patients were allocated to a study arm (XtraLok® or Intrafix®) by a computer-generated randomization table. In all patients, EndoButton® (Smith &
Nephew, Andover, MA) was used for femoral fixation and the Mitek tensioner was employed. The patients were assessed with KT-1000 arthrometer manual maximum measurements taken at six weeks, three and six months post-operatively by independent clinicians. Mean measurements between the two groups were compared using the student-t test at the above intervals. At six months, eighty-seven of one hundred and three (84%) patients were available for follow-up; 43 XtraLok (XL), and forty-four Intrafix (IF). There was no significant difference between groups in mean age and gender. KT-1000 arthrometer side-to-side differences at six weeks were 1.04mm (XL) versus 1.14mm (IF), and 0.96mm (XL) versus 1.38mm (IF) at three months. At these intervals, differences between the groups are not statistically significant (p=0.87 and p=0.34, respectively). At six months, KT-1000 side-to-side difference was 1.26mm (XL) versus 2.41mm (IF), which is statistically significant (p=0.017). In clinical results at six months, ACL fixation with Bioscrew XtraLok shows decreased laxity compared to the Intrafix device.
We used a high frequency response, ultra-thin transducer to measure forefoot pressures at predetermined sites on the sole of the foot in 10 normal subjects. We demonstrated impact pressure peaks, which have not previously been identified, and which were separate from the roll-off peak. We report preliminary results on the effect of various forms of footwear and insoles on sub-pedal pressure during walking.
A manufacturing technique to increase the bonding between bone cement and metal prostheses has been assessed in the laboratory by "push-out" tests, and the effects of contamination of the cement and of the prosthesis with blood and intramedullary contents have been studied. The technique, known as pre-coating, increases bond strength; this increase is preserved after contamination of the cement which does, however, cause some lowering of interface shear strength. The implications for clinical practice are discussed.
