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Biomedical subjects

W D Cannon

Publications and source records attributed to W D Cannon.

10 recordsLinked to original sources
PubMed1992

AIDS and arthroscopic surgery.

There are an estimated 8 to 10 million people worldwide infected with human immunodeficiency virus (HIV). The true extent of infection in the population is unknown, and many are unaware of their HIV status. Arthroscopic and arthroscopically assisted surgery is less invasive and bloody than other orthopaedic procedures, and seemingly less hazardous to surgeons. Nevertheless, the potential for exposure exists. Arthroscopic surgeons routinely experience gown, face-mask and shoe-cover saturation from the splashing of blood-tainted irrigation fluid. Glove perforations by needles, sharps, and bone fragments can occur. Bone and tissue allografts pose risks to both surgeon and patient, as HIV has been recovered from fresh, frozen and freeze-dried specimens. The process of cleaning and disinfecting arthroscopes adequately can damage these expensive devices. This article addresses the safeguards that arthroscopic surgeons should take to prevent exposure to HIV. Effective sterilizing and disinfecting techniques for arthroscopes are also discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The role of arthroscopic debridement after anterior cruciate ligament reconstruction.

This retrospective study included 55 patients who had prior anterior cruciate ligament (ACL) reconstruction; 30 made up the experimental group who had arthroscopic debridement of impinging soft tissue and 25, who did not have a second-look arthroscopy, were used as controls. Impinging tissue was not necessarily the primary reason for arthroscopy in the experimental group. Only nine patients (30%) were debrided solely because of anterior symptoms suggestive of soft tissue impingement; 16 (53%) underwent arthroscopy primarily to assess meniscal repairs; five (17%) were done in conjunction with hardware removal. Both groups were evaluated for pain, crepitation, and anterior laxity at three specific times. Debridement reduced crepitation from 35% to 8% in patients with moderate crepitus, and from 50% to 38% in patients with mild symptoms. The percentage of patients without crepitation increased from 15% to 54% by final follow-up. Predebridement, 14% of patients had moderate pain, and 53% mild pain. By final follow-up, 38% had mild pain and 62% were pain free. Patients benefitted from debridement regardless of method of ACL reconstruction. Arthroscopic debridement did not increase anterior knee translation. Both groups gained extension and had improved activity levels with the passage of time from ACL surgery.

Adult↗
PubMed1990

Peripheral meniscal tears: MR findings after conservative treatment or arthroscopic repair.

Follow-up knee magnetic resonance (MR) examinations were performed on 17 patients (18 menisci) with arthroscopically proved tears of the outer third of the meniscus who were treated either conservatively (six patients) or with surgical repair (11 patients). All patients satisfied accepted clinical orthopedic criteria for meniscal healing. MR examinations obtained 3-27 months after injury revealed persistent signal intensity (grade 3), unchanged from that seen on the preoperative study, in all 15 patients in whom both pre- and postoperative studies were obtained and in three of four menisci that were proved to be healed at second-look arthroscopy. It appears that grade 3 signal from both conservatively treated and repaired menisci may persist long after the tear has become asymptomatic and has presumably healed. The presence of such signal should not be interpreted as necessarily indicating meniscal retear in these patients. Persistent signal intensity at the site of previous injuries may account for some reported cases of disagreement between MR and arthroscopic findings.

Adolescent↗
PubMed1990

Arthroscopic debridement of the arthritic knee.

Arthroscopic debridement was carried out in 49 knees of 44 patients. These patients, who had a primary diagnosis of arthritis, were older than 50 years of age. Two-thirds had roentgenographic evidence of severe arthritis. Age, weight, compartment location of arthritis, and presurgical range of motion did not affect surgical results. Symptoms of long duration, arthritic severity as evidenced by roentgenograms, and malalignment predicted poor results. Conversely, shorter duration of symptoms, mechanical symptoms, mild to moderate roentgenographic changes, and crystal deposition correlated with improved results. Surgery offered no benefit for 39% of the patients. Another 9% had temporary improvement, averaging 15 months, but were judged failures at the final follow-up examination. Good or excellent results were achieved in 52% of the patients and maintained through the final follow-up examination in 40% of the patients. Of these, two-thirds had no visible deterioration within a 33-month average follow-up period.

Aged↗
PubMed1988

Anatomy and biomechanics of the anterior cruciate ligament.

The ACL is an important living soft-tissue component of ancient origin that acts in combination with other complex structures to provide control of femorotibial kinematics. The effect on the knee of its loss, resulting in disruptive kinematics and often subsequent degenerative changes, probably occurs not only because of its lack of structural integrity but also perhaps because of disruption of its proprioceptive function. The complexity of this ligament and associated normal kinematics of the knee challenges the ability of orthopaedists to devise effective therapeutic measures to reconstitute its function when lost. A clearer understanding of the normal role of the ACL will aid in this effort.

Biomechanical Phenomena↗
PubMedDate not supplied

Instrumented testing of functional knee braces.

The ability of seven functional knee braces to control anterior tibial displacement in three severely lax ACL deficient knees using two instrumented testing devices was studied. Some braces were statistically shown to be much better in this regard than others, but not all data obtained was statistically significant. This material should aid one in determining which braces offer the greatest degree of control of anterior tibial displacement in patients with ACL insufficiency.

Analysis of Variance↗
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↗