Biomedical subjects

W D Cannon

Publications and source records attributed to W D Cannon.

21 records · Page 2Linked to original sources

PubMedDate not supplied

The incidence of healing in arthroscopic meniscal repairs in anterior cruciate ligament-reconstructed knees versus stable knees.

In this study, follow-up data was obtained in 90 of 117 consecutive meniscal repairs. In Group I, there were 68 meniscal repairs in conjunction with anterior cruciate ligament reconstruction, and in Group II, 22 isolated repairs in anterior cruciate ligament stable knees. Meniscal healing was assessed using the criteria established by Henning, by either arthroscopy or arthrography, at a mean of 7 months for isolated repairs and a mean of 10 months for repairs done in conjunction with anterior cruciate ligament reconstruction. Average time from injury to surgery was 19 months in Group I patients, and 14 months in Group II patients. The overall rate of successful healing was 82%. Group I repairs were successful 93% of the time compared to a 50% success rate in Group II (P less than 0.00005). Lateral meniscal repairs fared better than medial repairs in both groups. Although a smaller rim width yielded better overall healing, there was no difference in the mean rim width of the two groups. Patients with anterior cruciate ligament reconstruction did better than those with isolated meniscal repair, regardless of tear length. Older patients had better healing than younger ones. Overall, acute repairs were more successful than repairs of chronic tears. Even so, the chronic Group I patients had a 91% successful healing rate.

Adolescent↗

PubMedDate not supplied

Elongation of arthroscopically tied knots.

It has been postulated that some arthroscopic shoulder stabilization failures may be due to knot slippage. In an effort to improve arthroscopic technique, we performed tensile testing on four arthroscopically tied knots with two commonly used suture materials. Handtied square knots served as controls. Sutures of No. 1 Maxon and No. 1 Ticron were used. Four types of sliding knot configurations were tested: the overhand loop, the Duncan loop, the Roeder knot, and the Snyder knot. Knots were tied via a knot pusher, and testing was performed in a normal saline-filled thermoplastic chamber. Knots were tied around two rings connected to a Bionix 858 materials testing apparatus. The knots were tested under conditions of cyclic loading and loading to failure. Results of the testing revealed that the most important factor in knot security was the type of suture material, although there were differences with the type of knot. With the Maxon suture, there was significantly decreased ultimate failure load of all of the arthroscopically tied knots compared with handtied square knots. Knots tied with Ticron were similar in strength for both arthroscopically and handtied groups. The surgeon who chooses a monofilament absorbable suture should be aware that a high percentage of knots fail under low load cyclic testing, and that all of these knots were inferior to handtied square knot controls in testing to failure.

Arthroscopy↗

PubMedDate not supplied

Arthrometric evaluation of posterior cruciate ligament injuries.

We reviewed the clinical examinations and knee arthrometry evaluations of 40 patients: 10 with posterior cruciate ligament injuries, 10 with combination anterior and posterior cruciate ligament injuries, 10 with anterior cruciate ligament injuries alone, and 10 with no history of knee injury. Using a 3-mm side-to-side difference as the minimal limit for detection of posterior cruciate ligament injury, the sensitivity of the arthrometer at 40 pounds of posterior force was 90%, the specificity was 100%, the predictive value of a positive test was 100%, and the predictive value of a negative test was 91%. When total anterior-posterior translation was assessed, the sensitivity was 100%, the specificity was 85%, the predictive value of a positive test was 87%, and the predictive value of a negative test was 100%. The overall accuracy of arthrometry for detection of posterior cruciate ligament injury was 96% for 40 pounds of posterior force and 94% for total anterior-posterior translation at 40 pounds. Grade 1 posterior cruciate ligament injuries had significantly greater arthrometric posterior translation compared with grade 0 (normal) knees. Regression analysis showed arthrometric laxity measurements correlated well with the clinical grade of the posterior drawer test. Finally, the accuracy of the arthrometer was not affected by concomitant anterior cruciate ligament injury.

Adolescent↗