Anterior cruciate ligament injury rates are reported to be two to eight times higher in women than in men within the same sport. Because the menstrual cycle with its monthly hormonal fluctuations is one of the most basic differences between men and women, we investigated the association between the distribution of confirmed anterior cruciate ligament tears and menstrual cycle phase. Sixty-nine female athletes who sustained an acute anterior cruciate ligament injury were studied within 24 hours of injury at four centers. The mechanism of injury, menstrual cycle details, use of oral contraceptives, and history of previous injury were recorded. Urine samples were collected to validate menstrual cycle phase by measurement of estrogen, progesterone, and luteinizing hormone metabolites and creatinine levels at the time of the anterior cruciate ligament tear. Results from the hormone assays indicate that the women had a significantly greater than expected percentage of anterior cruciate ligament injuries during midcycle (ovulatory phase) and a less than expected percentage of those injuries during the luteal phase of the menstrual cycle. Oral contraceptive use diminished the significant association between anterior cruciate ligament tear distribution and the ovulatory phase.

We evaluated 38 subjects with isolated posterior cruciate ligament-deficient knees at a mean of 13.4 years (range, 5 to 38) after injury to study the occurrence of symptoms, disabilities, and articular degeneration. Each subject completed a standardized questionnaire, physical examination, and had radiographs taken of both knees. Eight (21%) patients had surgeries for meniscal injuries after their posterior cruciate ligament injuries. The mean questionnaire score for function (50-point maximum) was 34.4 +/- 6.5 (SD) for the patients who did have meniscal surgeries versus 40.0 +/- 8.7 for the 30 patients who did not (P = 0.05). Among the 30 patients with isolated posterior cruciate ligament-deficient knees with normal menisci, 24 (81%) had at least occasional pain and 17 (56%) had at least occasional swelling. As time from injury increased, increased articular degeneration on radiographs was seen (P = 0.037). Our study suggests that the prognosis for the isolated posterior cruciate ligament-deficient knee varies. Some patients experience significant symptoms and articular deterioration, while others are essentially asymptomatic and maintain their usual knee function.

Magnetic resonance (MR) and ultrasound (US) imaging are currently touted for assessment of rotator cuff disease. Optimum clinical imaging techniques include use of (a) a 1.5-T MR imaging unit with small planar coils, proton-density-weighted and T2-weighted fast spin-echo sequences, and 10-12-cm fields of view (yielding 400-470 x 500-625-microm in-plane spatial resolution) and (b) a state-of-the-art commercial US unit with insonation frequencies of 9-13 MHz (yielding 200-400-microm axial and lateral resolution). Proper diagnosis requires familiarity with normal anatomic characteristics and imaging pitfalls. Care must be taken to avoid sonographic tendon anisotropy and MR imaging magic angle effects, which can be misinterpreted as rotator cuff tear. At MR imaging, a complete cuff tear typically appears as either a hyperintense defect or a tendinous avulsion that extends from the bursal to the articular side of the cuff; a partial cuff tear typically appears as a focal hyperintense region that contacts only one surface of the cuff. Complete and partial tears manifest with a wide spectrum of findings at US. MR imaging and US are effective for evaluating rotator cuff injuries, with high reported accuracies for detection of complete tears but more disparate results for detection of partial tears.

No abstract

No abstract

No abstract

Recent epidemiological, clinical, and biomechanical studies have implicated axial impact to the plantar surface of the foot to be a cause of lower extremity trauma in vehicular crashes. The present study was conducted to evaluate the biomechanics of the human foot-ankle complex under axial impact. Nine tests were conducted on human cadaver below knee-foot-ankle complexes. All specimens were oriented in a consistent anatomical position on a mini-sled and the impact load was delivered using a pendulum. Specimens underwent radiography and gross dissection following the test. The pathology included intra-articular fractures of the calcaneus and/or the distal tibia complex with extensions into the anatomic joints. Impactor load cell forces consistently exceeded the tibial loads for all tests. The mean dynamic forces at the plantar surface of the foot were 7.7 kN (SD = 4.3) and 15.1 kN (SD = 2.7) for the nonfracture and fracture tests, respectively. In contrast, the mean dynamic forces at the proximal tibial end of the preparation were 5.2 kN (SD = 3.1) in the nonfracture group, and 10.2 kN (SD = 1.5) in the fracture group. The foot and tibial end forces were statistically significantly different between these two groups (p < 0.01). The present investigation provides fundamental data to the understanding of the biomechanics of human foot-ankle trauma. Quantifying the effects of other factors such as gender and bone quality on the injury thresholds is necessary to understand foot-ankle tolerance fully.

No abstract