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Biomedical subjects

J H Calhoun

Publications and source records attributed to J H Calhoun.

At least 37 records · Page 2Linked to original sources
PubMed1995

Osteomyelitis.

The complexities of osteomyelitis make its diagnosis and treatment challenging. Current trends emphasize early diagnosis and aggressive treatment. Imaging has improved, with nuclear scans and magnetic resonance imaging, and technique modifications have enhanced the specificity of these tests. Treatment depends on thorough debridement of necrotic bone and tissue, accurate cultures and administration of culture, and sensitivity-specific antibiotics. Antibiotic delivery has expanded to include effective oral agents and local agents mixed with polymethylmethacrylate or a biodegradable substance. Success rates in treating this disease have improved with the use of a systematic approach, making outcome more predictable.

Adult↗
PubMed1995

An anatomic analysis of endoscopic plantar fascia release.

Eighteen fresh-frozen cadaver foot specimens underwent release of the plantar fascia via a newly described endoscopic technique. A 75% release was attempted on each specimen in order to represent a partial fascial release. Each specimen was then dissected to assess the success of the procedure. Five separate measurements were recorded evaluating the reproducibility of the procedure, adequacy of the release considering accepted etiologies for chronic heel pain, and the possibility of damage to local structures. Partial release was noted to be possible, but controlling the exact percentage of the incision was difficult. The release averaged 82% of the width of the fascia, with a range of 53% to 100%. There was no damage in any specimen to the first branch of the lateral plantar nerve, the structure considered most at risk during the procedure. Release of the deep fascia of the abductor hallucis muscle was not possible with this approach.

Cadaver↗
PubMed1995

Injuries of the foot related to the use of lawn mowers.

We managed thirty-three patients who had open injuries of the foot related to the use of a lawn mower from 1985 through 1992. Twenty-eight of the patients were male and five were female. They ranged in age from four to seventy-three years old. The injuries were associated with the use of push lawn mowers (twenty-two patients), riding lawn mowers (nine patients), and self-propelled lawn mowers (two patients). The injuries included forty open fractures, twenty amputations, eighteen lacerations of the skin and nail beds, nine lacerations of tendons, two closed fractures, segmental loss of bone in two patients, and segmental loss of the Achilles tendon in one patient. The findings on culture of intraoperative specimens revealed a mean of 3.1 organisms (range, one to nine organisms) per patient. All of the patients were managed with at least one operative procedure (mean, 2.4 operations; range, one to five operations), and all were treated with parenteral antibiotic therapy (mean, 2.3 antibiotics; range, one to six antibiotics) except for one patient who had oral antibiotic therapy. The mechanism of injury was documented for twenty of the twenty-two patients who had been injured by a push lawn mower. Seventeen patients were injured while pulling the push lawn mower backward, and eight of those patients had been pulling the lawn mower up a slope.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Home↗
PubMed1995

Ring fixators for reconstruction of traumatic disorders of the foot and ankle.

External fixation methods have an accepted place in orthopedic management of problems involving the foot and ankle. Traditionally, reconstruction and correction of deformity have been managed with extensive soft-tissue release, osteotomies, and arthrodeses. Methods of external fixation have evolved dramatically over the past decade with the introduction of the techniques of Ilizarov to the Western World. This article covers ankle arthrodesis, burn scar contracture, distal tibial deformity, and fractures.

Adult↗
PubMed1994

Osteomyelitis.

Osteomyelitis can be difficult to treat. Current trends emphasize early diagnosis and aggressive treatment. Imaging has improved with nuclear scans and magnetic resonance imaging, and recent modifications in technique have enhanced the specificity. Treatment depends on debridement of necrotic bone and tissue, obtaining accurate cultures, and administration of culture- and sensitivity-directed antibiotics. Antibiotic delivery has expanded to include effective oral agents and local agents mixed with polymethylmethacrylate or a biodegradable substance. Success rates in treating this disease have improved with a systematic approach, making outcome more predictable.

Chronic Disease↗
PubMed1994

A comprehensive study of pressure distribution in the ankle joint with inversion and eversion.

The understanding of load transfer characteristics is the baseline for biomechanics of the ankle joint. Changes in contact patterns of the articular cartilage from the norm may indicate pathologic conditions. Measurement of the contact in human cadaver ankles provides a direct measurement for this understanding. The force transfer characteristics of the three facets of the ankle joint were investigated. Five fresh-frozen cadaver lower extremities were tested in 12 positions under three axial loads of 490, 686, and 980 N. Fuji film served as the pressure transducer and the prints were analyzed by a computerized video digitizer. The results demonstrated that as the foot was moved into inversion or eversion with the ankle in neutral flexion or dorsiflexion, there was a decrease in total contact area and an increase in the average high pressure. In plantarflexion, the contact area was lower and the average high pressure was higher, indicating a greater force per unit area as compared with dorsiflexion and neutral flexion. In plantarflexion, however, little change was noted with inversion or eversion. In dorsiflexion, the total contact area was higher and the average high pressure slightly lower as compared with neutral flexion. With inversion, the contact area of the medial facet of the ankle increased and with eversion it increased on the lateral facet, especially in dorsiflexion. With an increase in loading, the pressure did not significantly increase but the contact area did increase. The centroid of the contact moved anteriorly to posteriorly on the talus as the joint moved from dorsiflexion to plantar-flexion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Use of antibiotic-PMMA beads in the ischemic foot.

Thirty-six patients with 44 ischemic foot infections were managed with antibiotic-polymethylmethacrylate (PMMA) beads. Most of these patients received gentamicin-impregnated PMMA beads but tobramycin and vancomycin-impregnated PMMA beads were used on three patients. Angiopathy occurred in 35 patients secondary to diabetes and secondary to renal disease in 2; 1 patient had both diabetes and renal disease. The most common bacteria was Staphylococcus aureus (82%), although other organisms and multiple bacteria were present. In spite of the variability of the bacteria, PMMA beads were helpful in managing foot infections in this difficult patient population.

Anti-Bacterial Agents↗
PubMed1994

Osteomyelitis.

Explore the source record for details and available documents.

Humans↗
PubMed1994

The Ilizarov technique in ankle fusion.

Failed ankle arthrodesis represents a significant challenge to the orthopaedist today. The complexity of this problem is further increased when associated with additional complications, such as osteomyelitis, leg length discrepancy, or concomitant foot deformity. In many instances, the only viable salvage alternative is amputation. The authors report 21 cases of complex distal tibial pathology or failed ankle arthrodesis treated with the Ilizarov external fixator. Of the 20 cases available for follow-up evaluation, 16 (80%) achieved good results with solid ankle arthrodesis and resolution of associated pathology. The Ilizarov fixator may be a viable clinical tool in these difficult cases in which amputation is the alternative.

Adolescent↗
PubMed1993

Sporotrichosis presenting as arthritis and subcutaneous nodules.

Arthritis is a rare manifestation of systemic sporotrichosis. A patient who had sporotrichal arthritis of both wrists and elbows is described. Predisposing factors included alcoholism, rose gardening, and antecedent trauma. The onset of the arthritis was insidious, and the diagnosis was made 2 1/2 years after his first symptoms were noted. Treatment with surgical debridement and a 23-week course of ketoconazole was unsuccessful. A review of the literature suggests that some combination of intravenous or intraarticular amphotericin B and potassium iodide, ketoconazole, or surgery is necessary for effective treatment.

Arthritis, Infectious↗
PubMed1993

Treatment of infected pilon nonunions with small pin fixators.

Six consecutive patients with infected intra-articular fractures of the distal tibia were studied. They were treated with resection of all infected or necrotic bone, systemic antibiotics, and instrumentation with a small pin fixator (Ilizarov external fixator). The fixator was used to perform an ankle arthrodesis and to fill the defect created by bone resection with distraction osteogenesis. In all cases, the infections were eradicated, and a solid arthrodesis was attained. The patients required from zero to two revision procedures (average 1.3), and their time in the fixator varied from 3 to 13 months (average 8 months). All of the patients experienced at least minor complications during treatment (superficial pin tract infections). At final follow-up, no patient demonstrated shortening of more than 1.5 cm. One patient has an internal rotation deformity of 15 degrees; a second has a varus deformity of 10 degrees and occasionally uses lateral support (a cane) secondary to unsteadiness on uneven ground; and one patient uses aspirin occasionally for subtalar pain. All are pleased with their results and would undergo the same procedure again without reservation.

Adult↗
PubMed1993

The Ilizarov fixator and polymethylmethacrylate-antibiotic beads for the treatment of infected deformities.

Eighteen of the 124 patients enrolled in the gentamicin methylmethacrylate bead (GMB; Septopal) study had infected deformities that were treated with the Ilizarov external fixator. Nine of these patients (Group 1) were treated with an initial debridement and intravenous antibiotics for four weeks. Nine patients (Group 2) were treated with GMB and, five days after operation, intravenous antibiotics. The two groups were similar. Group 1 included eight men and one woman (average age, 31.8 years) and Group 2, seven men and two woman (average age, 37.4 years). Both groups had multiple deformities, including nonunions, segmental defects, angulation, and shortness. The end results were identical. Eight patients in each group had their infection successfully arrested (88.9%), and eight patients in each group had their deformity successfully treated. The use of GMB with the Ilizarov fixator was as effective as long-term parenteral antibiotics with the Ilizarov fixator for the treatment of infected deformities.

Adult↗
PubMed1993

The treatment of infected nonunions with gentamicin-polymethylmethacrylate antibiotic beads.

Fifty-two patients enrolled in the Septopal study of infected nonunions were prospectively examined in a randomized, controlled, closed study. Patients were divided into two groups. Group 1 consisted of 24 patients treated with debridement and intravenous antibiotics for four weeks. Group 2 consisted of 28 patients treated with debridement, gentamicin-polymethylmethacrylate (Septopal) beads, and perioperative broad-spectrum parenteral antibiotics. Both groups were treated with similar methods for reconstruction of the nonunions. The demographics of the two groups were similar. The average patient age in Group 1 was 38.4 years, and in Group 2, 37.1 years. Group 1 included 21 men and three women and Group 2, 23 men and five women. The nonunions in both groups ranged from simple hypertrophic nonunions to atrophic unions to segmental defects. The end results were good in both groups. Twenty patients in Group 1 and 25 patients in Group 2 had their infections successfully arrested (83.3% and 89.3%, respectively). Nonunions were successfully healed in the two groups, with similar results (Group 1, 83.3%; Group 2, 85.7%). Infected nonunions responded equally well to either systemic treatment with long-term intravenous antibiotics or local treatment with gentamicin-polymethylmethacrylate beads.

Adult↗
PubMed1993

Comparison of the clinical efficacy and tolerance of gentamicin PMMA beads on surgical wire versus combined and systemic therapy for osteomyelitis.

These data do not prove a statistical superiority of conventional antibiotics or Septopal in the treatment of chronic osteomyelitis. This result, however, is complicated by the biased data set represented by the combined treatment. The data do suggest that cost of treatment is considerably less in patients who are treated with local antibiotics (i.e., Septopal) alone. The rate of adverse experiences was directly related to the use of parenteral antibiotics, with higher rates of adverse experiences in the conventional and combined treatment groups. Furthermore, the Cierny-Mader Physiologic Class had the best correlation with outcome, suggesting that host factors are probably of critical importance in inducing remission of chronic osteomyelitis. This protocol was not designed to test the role of debridement in the treatment of osteomyelitis: it was assumed that debridement would be the same in both groups. It is the investigators' strong opinion, however, that adequacy of debridement was an important determinant in quiescence or recurrence in the study patients. Similarly, there was no strict control for adequacy of soft-tissue coverage provided by local or distant tissue transfer. Again, the investigators believe that adequacy, including viability and durability, of soft-tissue covering was an important determinant for the end result in these patients. Other covariants such as smoking, history, nutritional status, and other measures of general health will be added to this model when data are available. This analysis will allow definition of the appropriate clinical situations in which use of Septopal alone or combined with parenteral antibiotic is indicated.

Anti-Bacterial Agents↗
PubMed1993

Salmonella typhi osteomyelitis in a nonsickle cell patient. A case report.

Few cases of osteomyelitis caused by Salmonella typhi in nonsickle cell patients have been reported. In a 33-year-old woman with a history of chronic, intermittent drainage of the right lower leg, roentgenographs indicated middiaphyseal osteomyelitis of the fibula. Bone cultures obtained at surgical debridement grew S. typhi. The patient responded adequately to four weeks of intravenous antibiotic therapy, and the infection has remained arrested after 18 months. The characteristics of S. typhi osteomyelitis are as follows: All reported cases have affected female patients with no apparent immunocompromise; all had a history of S. typhi infection with long bone involvement; and all had a tendency to recurrence.

Adult↗
PubMed1992

Infection in the diabetic foot.

A 56-year-old woman presented with a chronic infection of her right first toe. The woman had a 15-year history of diabetes mellitus and had been insulin dependent for the past five years. Her toe had been injured one month earlier when hit by a frozen chicken that fell out of the freezer. The accident caused a bruise and a small cut. Serous to purulent drainage then developed. When she presented, the toe was reddened and draining. Physical examination showed a nonobese woman with no fever or other evidence of systemic infection. The wound showed no evidence of necrotizing fasciitis. Peripheral pulses were 2+ and capillary refill was slow. Sensation in both feet was decreased. The transcutaneous oxygen tension in the feet was reduced at 20 mm Hg. Relevant laboratory findings included a serum glucose of 250 and creatinine of 1.5. X-rays of the foot were compatible with diffuse osteomyelitis of the distal phalanx of the great toe. Technetium and indium scans were positive, with increased uptake localized to the area of x-ray changes (Figure 1). The patient was admitted to the hospital.

Adult↗
PubMed1992

Rigidity of half-pins for the Ilizarov external fixator.

The success of the Ilizarov technique is due to the combination of the biomechanics of its external fixator and the biology of distraction osteogenesis. The stability and stiffness of the conventional Ilizarov fixator is attributed to its use of a K-wire cross structure. The disadvantages of this structure include pain, and possible neurologic and vascular injuries when the wires are introduced into crucial neurovascular areas, as well as increased frame complexity and construction. Reducing the number of wires decreases these problems, but also decreases the stiffness of the system. Hybrid (wire and half-pins) Ilizarov fixators and half-pin fixators are also being used in an attempt to alleviate these problems. Half-pins have been described by Fleming et al. and Green as causing minimal transfixation of the surrounding soft tissues and capable of and being inserted into anatomically safe areas. The stiffnesses of the hybrid systems have not been measured. This study reports on the stiffness of different wire and half-pin systems that were biomechanically tested in axial loading, anterior-posterior bending, medial-lateral bending, and torsional loading. The results demonstrated that the conventional Ilizarov fixator with wires possesses a high axial stiffness, whereas the fixator with half-pins possesses higher stiffness under bending and torsional loads. To obtain adequate stability, the use of hybrid Ilizarov frames with one wire and two or more half-pins (5 or 6 mm in diameter), or larger half-pin frames (5 or 6 mm) with three pins is recommended.

Biomechanical Phenomena↗