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Biomedical subjects

M C Harper

Publications and source records attributed to M C Harper.

At least 37 records · Page 2Linked to original sources
PubMed1991

The lateral ligamentous support of the subtalar joint.

A review of the ligamentous structures spanning the subtalar joint laterally, as well as within the sinus and canalis tarsi, is presented based on previous descriptions and a series of anatomic dissections. Defined supporting structures are categorized into superficial, intermediate, and deep layers. Of these, the inferior extensor retinaculum is seen to be a discrete, substantial structure readily accessible for ligament reconstructions involving both the ankle and subtalar joints.

Calcaneus↗
PubMed1990

Dorsal closing wedge metatarsal osteotomy: a trigonometric analysis.

Dorsal closing wedge osteotomies are commonly done in order to elevate and shorten the metatarsals in the management of severe metatarsalgia with callus formation. A trigonometric analysis reveals that a proximal closing wedge with a small (i.e., 2-mm) base will significantly elevate (approximately 1 cm), and slightly shorten a typical lesser metatarsal. Larger proximal wedge osteotomies in a lesser metatarsal would appear to have the potential for excessive elevation of the metatarsal head. Because of differences in metatarsal width and length, a proximal wedge in the first metatarsal will elevate the metatarsal head approximately twice the width of the wedge base. A distal closing wedge osteotomy will elevate a lesser metatarsal head approximately the width of the wedge base.

Humans↗
PubMed1990

Talar shift. The stabilizing role of the medial, lateral, and posterior ankle structures.

An effort was made to evaluate the importance of the supporting medial, lateral, and posterior ankle structures in preventing talar shift. A series of fresh autopsy specimen ankles were subjected to manual mediolateral and anteroposterior stressing of the talus as intact specimens and after deletion of credited stabilizing structures. The fibula and attached ligaments were major factors in preventing talar shift, both mediolaterally and anteriorly. The lateral supporting structures were also noted to securely stabilize the talus against posterior subluxation in the absence of the posterior and medial malleoli.

Fibula↗
PubMed1989

A modified pins-and-plaster technique incorporating early motion for fractures of the distal radius.

A modified pins and plaster technique allowing early wrist motion for comminuted intraarticular fractures of the distal radius was used in 14 patients. At an average of 12 days after injury, hinges were applied and the cast sectioned at the wrist. Wrist motion, controlled by the amount and site of cast removal, was allowed thereafter. This relatively simple method appeared to maintain a satisfactory fracture reduction and be advantageous in avoiding wrist stiffness. Careful attention to detail regarding pin placement is recommended.

Adult↗
PubMed1989

Metabolic bone disease presenting as multiple recurrent metatarsal fractures: a case report.

A case of adult hypophosphatasia involving a patient with recurrent bilateral metatarsal fractures is presented. This disorder, although relatively uncommon, is often associated with multiple pseudofractures and complete pathologic fractures of the lower extremity. It can be detected with routine laboratory analysis. Metabolic bone disease should be considered as a possible causative factor in patients with multiple "stress" fractures of the foot.

Adult↗
PubMed1989

Posterior instability of the talus: an anatomic evaluation.

A cadaver study was conducted to evaluate the role of the posterior tibial margin or posterior malleolus, as well as medial and lateral supporting structures, in providing posterior stability for the talus. Posterior malleolar fractures consisting of approximately 30%, 40%, and 50% of the articular margin on the lateral radiograph were created in specimens that were then subjected to posterior stressing. No posterior talar subluxation was noted in any specimen. Repeat stressing following removal of the medial malleolus again revealed no subluxation in any specimen. The lateral supporting structures, primarily the posterior fibulotalar and fibulocalcaneal ligaments, appeared to be the key structures providing posterior talar stability. If the fibula is stable in an anatomic position, feared posterior instability of the talus would not appear to be an indication for internal fixation of posterior malleolar fractures.

Ankle Joint↗
PubMed1989

A radiographic evaluation of the tibiofibular syndesmosis.

A radiographic evaluation of the normal as well as the progressively widened tibiofibular interval in the area of the syndesmosis was done using 12 fresh cadaver lower extremities. The width of the tibiofibular "clear space" and the amount of tibiofibular overlap was determined on accurately positioned anterior-posterior and mortise radiographs. Based on a 95% confidence interval, measurements obtained for the intact specimens would support the following criteria as consistent with a normal tibiofibular relationship: (1) a tibiofibular "clear space" on the anterior-posterior and mortise views of less than approximately 6 mm; (2) tibiofibular overlap on the anterior-posterior view of greater than approximately 6 mm or 42% of fibular width; (3) tibiofibular overlap on the mortise view of greater than approximately 1 mm. The width of the tibiofibular "clear space" on both anterior-posterior and mortise views appeared to be the most reliable parameter for detecting early syndesmotic widening.

Ankle Joint↗
PubMed1989

Correction of metatarsus primus varus with the Chevron metatarsal osteotomy. An analysis of corrective factors.

A trigonometric evaluation of the amount of correction of metatarsus primus varus obtainable via lateral displacement of the first metatarsal head in a Chevron osteotomy technique revealed that approximately 1 degree of correction may be obtained for each millimeter of lateral shift. This calculated correction was correlated with the actual correction obtained in ten feet. Narrowing of the metatarsal head associated with removal of the medial eminence was an additional corrective factor.

Adult↗
PubMed1988

Viscous isoamyl 2-cyanoacrylate as an osseous adhesive in the repair of osteochondral osteotomies in rabbits.

An in vivo study of viscous isoamyl 2-cyanoacrylate used in limited amounts as an osseous adhesive was performed to evaluate the ability of the monomer to maintain the reduction of an unstable intra-articular osteochondral osteotomy as well as to allow for healing around the sites of adhesive placement. A histologic evaluation of any inflammatory reaction involving adjacent bone, cartilage, or synovium was also performed. Osteochondral fragments were created in 48 rabbit knees. In 24 knees, reduction of the fragment was secured with one small drop of adhesive at either end of the osteotomy surface. In 24 control knees, no adhesive was used. Ninety-six percent of the osteotomies in the adhesive treated group healed versus 50% of the control group. This difference is statistically significant (p less than 0.05). Osseous and cartilaginous healing was noted to proceed in an apparently unimpaired fashion around the sites of adhesive placement, and no inflammatory reaction involving adjacent viable tissue was evident.

Animals↗
PubMed1988

The deltoid ligament. An evaluation of need for surgical repair.

Forty-two patients were treated surgically for ankle injuries, including complete disruption or incompetency of the deltoid ligament, without any surgical repair as part of the initial operation. In a retrospective study, 36 patients were followed for one year or longer. The functional results appeared satisfactory provided surgical reductions of the medial joint space and lateral malleolus were accurate and maintained until bone repair was complete. No evidence of ligamentous instability of the foot or ankle was noted.

Adult↗
PubMed1988

Posterior malleolar fractures of the ankle associated with external rotation-abduction injuries. Results with and without internal fixation.

Thirty-eight patients in whom a fracture of the posterior malleolus was shown to comprise 25 per cent or more of the articular surface on the lateral radiograph were followed for an average of forty-four months (range, twenty-four to ninety-nine months). All injuries were judged to be a result of external rotation or abduction of the talus. Fifteen patients had fixation of the posterior malleolus, and twenty-three did not. Open reduction and internal fixation was carried out on all associated fractures of the medial and lateral malleoli. Satisfactory reduction of the posterior malleolus was often achieved when the fibula was reduced, and frequently this was maintained despite the absence of fixation. No posterior subluxation of the talus occurred in either group. No statistically significant difference was noted between the clinical results with and without fixation.

Adult↗
PubMed1988

Stabilization of osteochondral fragments using limited placement of cyanoacrylate in rabbits.

The higher homologues of the alkyl-2-cyanoacrylates appear to possess properties useful for an osseous adhesive. Considering currently available bonding strengths, the most reasonable potential application of an osseous adhesive would appear to involve the stabilization of relatively small osteochondral fragments. If used as a means of temporary internal fixation, such an adhesive would need to be used in limited amounts in limited areas to allow for normal healing processes to occur between areas of adhesive placement. An animal study was therefore conducted utilizing the viscous isoamyl-2-cyanoacrylate monomer to evaluate its ability to maintain the reduction of an unstable osteochondral fragment while allowing for healing around the sites of adhesive placement. Used in limited quantities, this monomer appeared to allow adjacent healing to occur unimpeded and to be nontoxic to adjacent viable bone and cartilage. This adhesive also appeared to lend significant stability to the reduction of an osteochondral fragment in the knees of a series of rabbits.

Animals↗
PubMed1987

Deltoid ligament: an anatomical evaluation of function.

A cadaver study done to evaluate function of the deltoid ligament and its major subdivisions, the superficial and deep components, revealed that the deltoid ligament is the primary restraint against valgus tilting of the talus, with superficial and deep components being equally effective in this regard. The deep deltoid ligament appeared to be the secondary restraint against both lateral and anterior talar excursion, with the lateral malleolus and supporting ligaments being the primary restraint.

Ankle Joint↗
PubMed1987

Curvature of the femur and the proximal entry point for an intramedullary rod.

The degree of anterior curvature of 14 human femurs and four currently marketed intramedullary rods was analyzed with the use of an interactive graphic computer program. The radius of curvature of the femurs ranged from 188.5 to 68.9 cm (average, 114.4 cm). The radius of curvature of three of the four rods analyzed fell beyond the spectrum of radii found in the human femurs. A concomitant investigation of the most appropriate proximal entry site for an intramedullary rod was done based on the patterns of exit sites for both flexible guide wires and two intramedullary rods introduced in a retrograde fashion from the intercondylar notch in 14 matched pairs of human femora. The most appropriate area for proximal access into the medullary canal for these devices would appear to be at the junction of the femoral neck and the greater trochanter slightly anterior to or in the pyriformis recess.

Bone Nails↗