Eighteen males and two females (mean age, 26.5 years) underwent biomechanical assessment and Cybex evaluation prior to ACL reconstruction. Clinically, all patients had at least a 1+ grade with the Lachman, anterior drawer, and pivot shift tests, the majority being graded as 2+. Footswitch, high speed photography, force plate, and indwelling wire electrode data were collected while each subject performed free and fast walking, running, cutting, and stair climbing activities. During walking, single limb support times did not differ between the subject's involved and uninvolved limbs. Knee joint angles were similar between limbs during walking, running, and stair climbing maneuvers. Dynamic EMG tracings during walking demonstrated similar quadriceps and calf activity between limbs, while greater variation in hamstring firing was evident among subjects. During running, the involved limb had a longer duration of medial hamstring activity compared to the lateral hamstring. No significant differences were seen in either vertical or sagittal shear forces during free walking. During fast walking, higher midstance vertical forces (F2) were present in the involved limb (P less than 0.05). During running, the involved limb experienced lower vertical forces (P less than 0.05), while both anterior and posterior sagittal shear differences were insignificant. Straight cut maneuvers demonstrated significantly lower lateral shear and vertical forces in the involved limb (P less than 0.05). Lower lateral and sagittal shear forces in the involved limb (P less than 0.01 and P less than 0.05, respectively), combined with a reduced angle of the cut during the cross-cut maneuver, may be the first means to assess the functional pivot shift phenomenon ever documented.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty patients with old ruptures of the PCL were analyzed. Ten patients were untreated, and ten patients had reconstruction of the PCL with the medial head of the gastrocnemius. The patients' gait was analyzed using high speed photography, footswitches, electromyography, and force plate. Patients were studied while walking, running, and stair-climbing. A Cybex muscle strength evaluation was also performed. Clinically, all patients had moderate to severe posterior instability. Five of the 20 patients also had posterolateral instability. Cybex testing showed quadriceps deficits in both reconstructed and untreated groups when comparing involved and uninvolved limbs. The reconstructed group also had deficits on hamstring Cybex testing. Footswitch data showed only minimal abnormalities. Gait velocity of walking was 91% of normal with a normal cadence. There was no significant difference in the single limb support times between the involved and uninvolved limbs in walking, fast walking, or running. The photometric data showed a tendency for increased knee flexion during the midstance phase of the gait cycle in comparing involved and uninvolved limbs. The knee flexion angles during midstance were similar in the patients with posterior instability when compared to the patients with the additional posterolateral instability. Force plate data showed decreased foot-floor reaction in the untreated group during terminal stance while walking. Similar findings were found in the reconstructed group during running.(ABSTRACT TRUNCATED AT 250 WORDS)
Eleven patients, 2 years after ACL reconstruction with a patellar tendon graft, returned for follow-up testing consisting of: 1) subjective assessment and functional analysis, 2) objective examination for residual ligamentous instability, 3) isokinetic quadriceps and hamstrings strength assessment, 4) radiographic assessment, 5) instrumented measurement of anterior shear displacement via a knee arthrometer, and 6) force plate and film analysis while performing cutting maneuvers in a laboratory setting. All 11 patients had been tested preoperatively through all steps except the fifth. The group subjectively rated the postoperative knee as 83% of the preinjury status, an increase from a 53% mean prior to reconstruction. Six of 11 patients were able to return to their full preinjury level of competition, with or without a brace. Four patients had positive drawer tests, five had positive Lachman examinations, and all subjects had negative pivot shifts. Significant quadriceps torque deficits remained (P less than 0.0005), with the postoperative knee extensors approximately 85% of the contralateral limb. The involved limb hamstrings were equal in strength to the nonoperated limb. Radiographic evaluation revealed four, five, and four patients with positive findings of the patellofemoral joint, medial joint space, and lateral joint space, respectively. Only one patient had normal radiographs. Instrumented knee laxity testing revealed the operated knee to be significantly looser only during maximum passive displacement (7.2 mm versus 5.3 mm, P less than 0.01) and not during the other measurements. Biomechanical analysis of the straight cut maneuver revealed no significant differences between the nonoperated and operated limbs at the 2 year postoperative mark.(ABSTRACT TRUNCATED AT 250 WORDS)
Fifty-three patients diagnosed as having one of several types of extensor mechanism disorders of the knee were randomly assigned to one of four treatment groups to assess the effects of one of four different modalities (ice, phonophoresis, iontophoresis, and ultrasound/ice contrast). Following four physical therapy treatments over a 10-day period, the group treated with the ultrasound/ice contrast demonstrated the greatest subjective improvement (47%). The pre- to post-treatment isometric strength resulted in a 28% improvement in knee extension strength and a 34% improvement in knee flexion strength. The authors emphasize that evaluation should include assessment of quadriceps tone and strength as well as careful palpation to determine the irritable structures. Ultrasound/ice is advocated as the most effective choice of the modalities tested for treatment of pain associated with extensor mechanism disorders. J Orthop Sports Phys Ther 1986;8(5):255-259.
Rehabilitation of the quadriceps femoris muscle is the cornerstone of full recovery after inactivity, immobilization, or surgery of the knee. Muscle strengthening programs often are interrupted by patients' complaints of pain experienced during exercise, which frequently prolong the patients' convalescence period. Specific modifications of standard quadriceps femoris muscle exercises often allow completely pain-free exercise, thus providing a faster progression of treatment and a subsequently shorter rehabilitation period. The purposes of this article are to review briefly patellofemoral biomechanics as it relates to quadriceps muscle rehabilitation and to summarize several modifications that in our clinical experience repeatedly have reduced pain during exercise.
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