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Biomedical subjects

Y S Hang

Publications and source records attributed to Y S Hang.

11 recordsLinked to original sources
PubMed1992

A dynamic study of the ankle-foot complex.

A kinematic study of the ankle-foot complex in 19 healthy volunteers was performed using computerized radiocinematography. We found that the instant centers of rotation of the ankle joint fell closely within the talus in the sagittal plane. When the ankle joint moved, the talus, the calcaneus and the navicular bone performed different excursions. Except for the movement in the sagittal plane, the calcaneus assumed eversion in dorsiflexion and inversion in plantar flexion when the ankle moved in an open kinematic chain (under non-weight-bearing conditions). In a closed kinetic chain movement (under weight-bearing conditions), the lower leg exhibited internal rotation, and the talus moved plantarward when the ankle was dorsiflexed. The internal rotation of the lower leg did not cause a slippery rotation of the foot on the surface, but rather it was converted into eversion of the calcaneus in the frontal plane.

Adolescent↗
PubMed1992

Effect of external load on isokinetic torque production by the knee in anterior cruciate ligament deficient patients.

The purpose of this study was to examine the effect of an external load on the isokinetic torque production of the knee directly from the anterior cruciate ligament (ACL) of deficient patients. Ten surgically proven ACL deficient patients were included in this study. Each patient was preoperatively studied using a Biodex isokinetic dynamometer. Isokinetic contraction of the quadriceps muscle and hamstring muscles were performed in five repetitions with an angular velocity of 45 degrees per second with proximal and distal pad placement, respectively. The results demonstrated that the ratio of torque production of the ACL deficient knee to the contralateral normal knee was greater in proximal pad placement than in distal placement and that the ratio of torque production of the knee in proximal pad placement to that of the knee in distal pad placement was greater in the ACL deficient knee than in the contralateral normal knee. Similar results were found for both extension and flexion of the knee. The results showed that ACL deficient patients felt more confident doing isokinetic contractions of the knee with proximal pad placement.

Adult↗
PubMed1991

Traumatic dislocation of the hip.

Of 125 patients with traumatic dislocation of the hips treated, 96 were reviewed retrospectively; 80 were males and 16 females with an age range from seven to 81 years (mean, 33.5 years). Motorcycle accidents were the leading cause of traumatic dislocation in this series (40 cases, 42%). Associated injuries were found in 68 cases (70.8%). Seventy-seven hips (80%) were reduced within 24 hours. In follow-up periods ranging from 15 months to 18 years (mean, 7.5 years), 56 patients had excellent or good results (58.3%). Statistical analysis of the clinical results showed that those patients with simple dislocations had better functional recovery. The earlier the reduction, the better the results. Associated injuries affected prognoses. Good results were obtained in patients with early, stable, and accurate reductions by either closed or open methods.

Accidents, Traffic↗
PubMed1990

Surgical treatment of tibial shaft fracture: experience of 207 cases.

From January 1984 to March 1988, 210 tibial shaft fractures in 207 patients treated by intramedullary nails, and by plate and screws and extraskeletal fixation were studied. There were 166 men and 41 women. Of the fractures, 95 (42.2%) of the 210 tibial shaft fractures were closed fractures and 115 (54.8%) were open fractures [Grade I: 44 (21.0%), Grade II: 39 (18.6%), and Grade III: 32 (15.2%)]. The incidence of associated injury was 44.3% and it was highest in the group with extraskeletal fixation (64.7%). Intramedullary nailing was performed in the majority of these fractures (127 out of 210) and yielded the best results in this series. Kuntscher's nailing resulted in nonunion in 3 cases (2.8%), superficial infections in 3 cases (2.8%) and deep infections in 4 cases (3.8%). Interlocking nailing resulted in nonunion in 1 case (4.8%), superficial infection in 1 case (4.8%) and deep infections in 3 cases (14.3%). Plate and screws fixation was performed primarily for metaphyseal fractures (71.4%) and resulted in nonunion in 4 cases (8.1%), superficial infection in 1 case (2.0%) and deep infection in 5 (10.2%). In the group treated with extraskeletal fixation, inasmuch as there were more cases of compromised soft tissue (open fracture, 97.1%), a higher incidence of associated major injuries (64.7%) and more cases of comminution of the bone (67.6%), the final results were less satisfactory. Nonunion was noted in 26.5% of the cases, superficial infection in 2.9% of the cases, and deep infection in 32.4% of the cases. From our study, we conclude that in appropriately selected patients, surgical fixation of tibial shaft fractures can produce a good functional recovery with an acceptable low rate of complications.

Adolescent↗
PubMed1988

A new jig for proximal tibial osteotomy.

The result of a proximal dome-shaped tibial osteotomy depends greatly on the accuracy of the surgical procedure. Contemporary jigs still are not sufficiently precise to provide three-dimensional guidance. A new jig was designed to place the pins correctly in both coronal and sagittal planes and to provide anterior advancement of the distal fragment of the tibia. The results obtained with this relatively simple device are predictable and reproducible.

Bone Nails↗
PubMed1979

Biomechanical study of the pitching elbow.

Medial-tension injuries of the pitching elbow are well recognized. One contributing factor is the extreme valgus which has been noted to occur during the acceleration phase of throwing. It is hypothesized that breaking pitches generate higher medial loading because of the pronation and supination required to impart spin to the ball. The pitching motion is a complex action of all body segments to produce maximum linear and angular acceleration of the ball. The purpose of this study was to correlate elbow loading with pitching style. We measured the forearm segment for axial and tangential (varus-valgus plane) acceleration using accelerometers attached to the forearm and hand. Muscle activity was measured by EMG. Forearm rotation was assessed by stroboscopic photography. Despite different delivery styles when throwing breaking pitches, each pitcher demonstrated patterns of muscle activity and acceleration which were similar. Deceleration forces were lower than acceleration forces. Pronation and supination were documented and contribute to the direction of ball spin. Accelerometers can be used to evaluate pitching mechanics. We suggest that the main factors causing an elbow injury are the amount of throwing and the force with which the ball is thrown.

Baseball↗
PubMed1979

Traumatic forequarter amputation: case report.

Traumatic forequarter amputation is rare and extremely mutilating. A 21-year-old male factory worker who sustained a traumatic shoulder girdle amputation is described. The injury mechanism was traction from the machine's force combined with the compressive force on the sternoclavicular joint. The factors leading to survival from this injury include rapid transportation, prompt and effective resuscitation, including treatment of shock, and adequate surgical management. Recognition of the complications associated with retrosternoclavicular dislocation is emphasized.

Accidents, Occupational↗
PubMed1979

Contracture of the hip secondary to fibrosis of the gluteus maximus muscle.

Twenty-eight children were treated who had limited flexion of the hips and various degrees of contracture of the abductor and external rotator muscles because of fibrosis of the gluteus maximus muscle. Although the lesions could be classified as those associated with poliomyelitis, infection of the gluteus maximus muscle, and fibrosis of unknown etiology, all forty-five hips had a typical restriction of motion such that an affected hip could not be flexed in the usual sagittal plane, but had to be flexed in abduction. Poliomyelitis may have been adjunctive to the causative factor of the lesion in some cases but the probable primary etiology was multiple intramuscular injections. Excellent correction of the hip contracture was achieved in all patients by division of the fibrotic bands.

Adolescent↗
PubMed1978

Abduction contracture of the shoulder. A report of two patients.

Two cases of winged scapulae due to fibrosis of the deltoid muscle are reported. The fact that these two patients were healthy and well prior to injections suggests that intramuscular injeciton is the causative factor. Treatment by simple division is satisfactory.

Adult↗
PubMed1977

Tibial lengthening: a preliminary report.

A preliminary review of 9 tibial lengthenings has been made to assess the value of a modification of the Anderson operation. The procedure can be carried out in one stage and is applicable to the older child and young adult. This is important as it may be used in the late or neglected case where epiphyseal arrest has failed or was never done. Five out of 9 patients in this series were skeletally mature. Leg lengthening procedures will always entail certain hazards. Complications occurred in 7 of the 9 patients, but were recognized early and expeditiously managed, and in several instances resulted in only minor deformity. The satisfactory end results in this series are attributable to the principle of limiting tibial lengthening to no more than 10 per cent of the overall bone length, i.e. 5 cm or less. No neurovascular complications occurred. Although tibial lengthening is hazardous and can cause severe disability, the results reported here suggest that in selected cases, it is a valuable procedure for correction of leg length discrepancy.

Adolescent↗