Search PubMed⌕ Search

Biomedical subjects

K J Koval

Publications and source records attributed to K J Koval.

At least 55 records · Page 3Linked to original sources
PubMed1997

Open reduction and internal fixation of the distal humerus: functional outcome in the elderly.

OBJECTIVE: To examine the functional outcome of a cohort of elderly patients after open reduction and internal plate and screw fixation of distal humerus fractures. DESIGN: Retrospective review of a consecutive series of patients older than 60 years of age who underwent plate and screw fixation of a distal humerus fracture. MATERIALS AND METHODS: Eighteen patients, aged 63 to 85 years (average, 71 years), underwent open reduction and internal fixation of a displaced distal humerus fracture using plates and screws. Three were Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) type A, 2 were type B, and 13 were type C fractures. The patients were reviewed at a minimum follow-up of 1 year after surgery. MEASUREMENTS AND MAIN RESULTS: All patients had a good or excellent clinical result using a standardized method of evaluation. General health status, as measured by the SF-36 Health Survey, was comparable to the published norms for U.S. male and female populations of similar age. CONCLUSION: Open reduction and internal fixation of the distal humerus in the elderly can provide good clinical results. Good clinical results, however, do not imply good general health status.

Aged↗
PubMed1997

Salter-Harris type III fracture-dislocation of the proximal humerus.

Salter-Harris type III fractures of the proximal humerus are rare injuries. We report a Salter-Harris type III anterior fracture-dislocation of the proximal humerus in a 10-year-old boy that was open reduced and internally stabilized. A bone scan performed during the initial hospitalization and at 2-year follow-up revealed devascularization and subsequent revascularization of the humeral head. At 2-year follow-up, the patient had full motion of the shoulder, no pain, and arm strength equal to that of the contralateral side. Four cases of Salter-Harris type III fractures of the proximal humerus have been previously reported; good early clinical outcomes were obtained in all. Despite devascularization of the epiphyseal fragment, excellent clinical outcomes may result.

Child↗
PubMed1997

Functional outcome after minimally displaced fractures of the proximal part of the humerus.

One hundred and four patients who had a minimally displaced fracture of the proximal part of the humerus (a so-called one-part fracture) were managed with a standardized therapy regimen and followed for more than one year. The clinical outcome was assessed on the basis of pain, function, and the range of motion of the shoulder. The duration of follow-up averaged forty-one months (range, twelve to 117 months). All fractures united without additional displacement. Eighty patients (77 per cent) had a good or excellent result, fourteen (13 per cent) had a fair result, and ten (10 per cent) had a poor result. Ninety four patients (90 per cent) had either no or mild pain in the shoulder, eight (8 per cent) had moderate pain, and two (2 per cent) had severe pain. Functional recovery averaged 94 per cent; forty-eight patients (46 per cent) had 100 per cent functional recovery. At the time of the most recent follow-up, forward elevation of the injured shoulder averaged 89 per cent; external rotation, 87 per cent; and internal rotation, 88 per cent that of the uninjured shoulder. The percentage of good and excellent results was significantly greater (p < 0.01) and external rotation was significantly better (p < 0.01) at the time of the latest follow-up for the patients who had started supervised physical therapy less than fourteen days after the injury than for the patients who had started such therapy at fourteen days or later.

Activities of Daily Living↗
PubMed1997

Improving the distal fixation of intramedullary nails in osteoporotic bone.

Twenty-four mildly osteoporotic human femurs were used to examine the fixation stability of several types of distal locking screws in osteoporotic femoral condylar segments. The fixated femurs were axially loaded to 1000 N at a rate of 100 N/sec to assess the locking screws' resistance to motion and then sinusoidally cycled to 10,000 cycles with a 500 N load to assess axial stability. Of the four screw configurations tested, the standard screws and the standard screws placed at a 30 degree crossing angle were significantly more stable (p < 0.05) than the step screw and osteoporotic bolt.

Bone Nails↗
PubMed1996

Canine bone response to tyrosine-derived polycarbonates and poly(L-lactic acid).

Tyrosine-derived polycarbonates are a new class of degradable polymers developed for orthopedic applications. In this study the long-term (48 week) in vivo degradation kinetics and host bone response to poly(DTE carbonate) and poly(DTH carbonate) were investigated using a canine bone chamber model. Poly(L-lactic acid) (PLA) served as a control material. Two chambers of each test material were retrieved at 6-, 12-, 24-, and 48-week time points. Tyrosine-derived polycarbonates were found to exhibit degradation kinetics comparable to PLA. Each test material lost approximately 50% of its initial molecular weight (Mw) over the 48-week test period. Poly(DTE carbonate) and poly(DTH carbonate) test chambers were characterized by sustained bone ingrowth throughout the 48 weeks. In contrast, bone ingrowth into the PLA chambers peaked at 24 weeks and dropped by half at the 48-week time point. A fibrous tissue layer was found surrounding the PLA implants at all time points. This fibrous tissue layer was notably absent at the interface between bone and the tyrosine-derived polycarbonates. Histologic sections revealed intimate contact between bone and tyrosine-derived polycarbonates. From a degradation-biocompatibility perspective, the tyrosine-derived polycarbonates appear to be comparable, if not superior, to PLA in this canine bone chamber model.

Animals↗
PubMed1996

Operative stabilization of fracture dislocations of the sacroiliac joint.

Posterior fracture dislocations of the sacroiliac joint (crescent fracture) represent a subset of lateral compression pelvic fractures. The crescent fracture consists of a posterior iliac wing fracture with extension into the sacroiliac joint and a dislocation of the inferior 1/2 of the sacroiliac joint. The posterior superior iliac spine remains firmly attached to the sacrum by the strong posterior ligaments. As a result of this combination of bony and soft tissue injury, the hemipelvis is rotationally unstable, but because the sacrospinous and sacrotuberous ligaments remain intact the involved hemipelvis is stable to vertically applied forces. Operative stabilization is necessary to restore articular congruity of the sacroiliac joint, pelvic stability, and to allow early mobilization of the patient. Stabilization of the pelvis may be achieved through either an anterior or a posterior approach with or without transarticular fixation. A posterolateral approach to the crescent fracture and a method of stabilization using extraarticular fixation, intertable lag screws and outer table antiglide plates are described. The results of using this technique in 22 patients are reviewed.

Fracture Fixation, Internal↗
PubMed1996

Patients with femoral neck and intertrochanteric fractures. Are they the same?

A prospective analysis was performed involving 680 geriatric patients with hip fractures to determine whether the demographic profile of patients with femoral neck fractures was similar to that of patients with intertrochanteric fractures. All patients were community dwelling, cognitively intact, previously ambulatory elderly with femoral neck or intertrochanteric fracture. Three hundred fifty-eight patients (52.6%) sustained a femoral neck fracture; 322 (47.4%), an intertrochanteric fracture. Patients with an intertrochanteric fracture were significantly older, more likely to be limited to home ambulation, and were more dependent regarding basic and instrumental activities of daily living. After stratification by gender and adjustment for age, these differences remained significant in women only. There were no differences in age, prefracture ambulatory ability, or dependence in activities of daily living in men with either type of fracture.

Activities of Daily Living↗
PubMed1996

The crescent fracture: a posterior fracture dislocation of the sacroiliac joint.

Between October 1987 and August 1992, 22 patients with crescent fractures, a posterior fracture-dislocation of the sacroiliac joint, were admitted, treated, and available for review at Tampa General Hospital and The Hospital for Special Surgery. The purpose of the study was twofold: (a) to evaluate the incidence, severity, and pattern of associated injuries, and (b) to determine the efficacy of a treatment protocol using a posterior extrapelvic approach and extraarticular internal fixation. The study population was composed of 13 females and nine males; the average age was 25 years (range 10-52). Despite the fracture pattern resulting in a rotationally unstable hemipelvis, all patients were hemodynamically stable at the time of presentation. Fourteen patients (64%) had other associated injuries, including five (23%) with closed head injury. In all cases a posterior extrapelvic approach was used with an anatomic reduction of the fractured iliac wing and the sacroiliac joint dislocation. Stable extraarticular internal fixation was obtained using intertable lag screws and outer-table neutralization plates. All the fractures were clinically and radiographically healed within 8-10 weeks postoperatively, and there were no acute wound, neurologic, or vascular complications. One patient developed osteomyelitis of the iliac crest 6 months postoperatively.

Adolescent↗
PubMed1996

Split fractures of the lateral tibial plateau: evaluation of three fixation methods.

A laboratory study was performed to compare the stability and ultimate strength of three standard fixation techniques for split-type lateral tibial plateau fractures. The three methods of fixation were (a) three 6.5-mm cancellous lag screws with washers; (b) two 6.5-mm cancellous lag screws with washers and an additional antiglide 4.5-mm cortical screw with washer; and (c) six-hole L-shaped buttress plate. Twelve pairs of embalmed mildly osteopenic lower extremities were used. Simulated split-type lateral tibial plateau fractures were created, reduced, and then instrumented in a matched pair design. The instrumented specimens were axially loaded to determine resistance to displacement, cyclically loaded to 10,000 cycles to determine dynamic stability, and then loaded to failure. There were no statistically significant differences found between resistance to displacement or failure strength as a function of either fragment size or sample bone density. On the basis of biomechanical stability, there appears to be no difference between the three fixation techniques tested. The results of this study suggest that use of an antiglide screw or buttress plate does not offer an advantage over lag screw fixation alone for the treatment of split type lateral tibial plateau fractures.

Biomechanical Phenomena↗
PubMed1996

Distal femoral fixation: a laboratory comparison of the 95 degrees plate, antegrade and retrograde inserted reamed intramedullary nails.

A biomechanical cadaver study was performed to compare the stability of three standard distal femoral fixation techniques. Eighteen mildly osteoporotic femurs were selected, based on a dual-energy x-ray absorption scanning bone density of 0.3-0.5 g/cm2 and a Singh index of III-IV. After initial mechanical characterization of these intact femurs, a distal femoral osteotomy was created, reduced, and stabilized under compression using random assignment to one of three methods of fixation: (a) six-hole 95 degrees supracondylar plate, (b) retrograde inserted statically locked supracondylar intramedullary nail, and (c) antegrade inserted statically locked Russell-Taylor nail. The instrumented femurs were mechanically tested, a 1-cm gap created, and the femurs retested. The specimens were finally loaded to failure in A-P three-point bending. The 95 degrees plate provided significantly stiffer fixation than the supracondylar intramedullary nail or Russell-Taylor nail in both a compressed transverse and gap distal femoral osteotomy model. The Russell-Taylor nail provided the least rigid fixation. The 95 degrees plate and Russell-Taylor nail had statistically significant greater loads to failure than the supracondylar intramedullary nail. These results support the use of a 95 degrees plate when maximum rigidity of fixation or maximum compression is desired.

Biomechanical Phenomena↗