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Biomedical subjects

M Purnell

Publications and source records attributed to M Purnell.

6 recordsLinked to original sources
PubMed1996

Injured stable knee with acute effusion: MRI evaluation.

This study was done to evaluate the magnetic resonance imaging (MRI) findings in acute traumatic effusions of the knee without ligament instability or radiographic abnormality other than the effusion. On reviewing the charts of 927 patients who had MRI of the knee, we found 114 patients who met the following criteria for inclusion in this study: (1) acute effusion by examination or history, (2) ligament stability on examination, and (3) normal findings on radiographs (excluding effusion). The total of 144 pathologic diagnoses made by MRI included bone injury (53%), disruption of the anterior cruciate ligament (19%), sprain of the medial collateral ligament (12%), medial meniscus tear (11%), lateral meniscus tear (5%), and rupture of the posterior cruciate ligament ( < 1%). Eight studies (7%) were read as normal. These MRI data are significantly different from data of previous studies using arthroscopy to evaluate acute knee injuries without ligament instability. The findings more accurately reflect the injury pattern seen in this setting because MRI can show both bone and soft tissue injury. From this study, we conclude that bone injury is the most common cause of acute effusion in the patient with ligament stability and normal radiographs.

Adolescent↗
PubMed1986

Hex-nut loosening following compression instrumentation of the spine.

Two cases of failure of compression instrumentation using the slotted hook and bushing (SHB) system due to back-off of the hex nut and loosening of the SHB. Laboratory tests on compression assemblies demonstrated that: hex-nut loosening can be produced in the laboratory by the cyclical loading of compression assemblies; crimping of the threads of the rod prevented hex-nut back-off and loosening of the SHB; crimping of the threads of the rod with the described rod crimper applied at a 90 degree angle did not damage the core of the rod or compromise its ability to withstand cyclical or tension loads; and crimping of the threads of the rod at angles other than 90 degrees damaged the core of the rod and significantly altered its ability to withstand cyclical loading. With subsequent clinical application of these principles, failure of compression instrumentation because of loosening of the SHB seems not to have been reported in the literature.

Adult↗
PubMedDate not supplied

Meniscal injuries associated with acute anterior cruciate ligament tears in alpine skiers.

We reviewed the records of 315 patients receiving an arthroscopically assisted stabilizing procedure for an acute anterior cruciate ligament injury incurred while alpine skiing to evaluate associated meniscal injuries. Meniscal injuries were classified by type, location, and treatment of the tear. Of the 317 knees operated on, all demonstrated an anterior cruciate ligament tear at arthroscopy. Ninety-eight percent of the injuries (310) were diagnosed within 3 days of injury, and 97% (307) were reconstructed within 28 days of injury. All tears occurred in the intrasubstance of the ligament; 32% were isolated injuries and 68% were combined with other injuries. In 159 patients with 170 meniscal tears 141 of the tears (83%) were lateral and 29 (17%) were medial. The injury triad of anterior cruciate ligament-medial collateral ligament-lateral meniscus was seen nine times as often as the anterior cruciate ligament-medial collateral ligament-medial mensicus combination.

Acute Disease↗
PubMedDate not supplied

Central quadriceps tendon for anterior cruciate ligament reconstruction. Part I: Morphometric and biomechanical evaluation.

We examined the anatomic and biomechanical adequacy of the central quadriceps tendon as an alternative graft source for anterior cruciate ligament reconstruction. Morphometry was performed on 15 preserved and 6 fresh-frozen specimens. Biomechanical testing was performed on the six fresh-frozen specimens. We initially used a triple suture through the tendon construction, and then clamping directly on the tendon. Morphometry yielded the following measurements: length, 6.1 +/- 1.0 cm; width, 2.7 cm (range, 2.1 to 3.7); and thickness, 7 mm (range, 6.4 to 7.8). The thickness was 1.8 times that of the patellar tendon. Biomechanical testing showed that suture failure occurred at 692 +/- 181 N, and tendon failure occurred at 1075 +/- 449 N. The load to tendon failure was 1.36 times that of a comparable-width patellar tendon graft, although the difference was not statistically significant. The failure mode was primarily through partial or complete tendinous avulsion, with only one specimen failing at midsubstance. These findings show the central quadriceps graft is of sufficient size and strength to be used for anterior cruciate ligament reconstruction.

Aged↗