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Biomedical subjects

K J Koval

Publications and source records attributed to K J Koval.

108 records · Page 6Linked to original sources
PubMed1992

Posttraumatic tibial osteomyelitis: a comparison of three treatment approaches.

The treatment of 25 tibias in 25 patients with posttraumatic chronic osteomyelitis was reviewed. The approaches to soft tissue management fell into three groups: 1) muscle flap coverage; 2) primary closure with suction irrigation; and 3) open cancellous bone grafting. Treatment success was judged by the presence or absence of drainage and the local signs or symptoms of infection, and by the status of the tibial nonunion. Overall, 19 of 25 tibias (76%) had successful treatment. We found flap coverage to have a higher success rate (80%) than either primary closure with suction irrigation (45.5%) or open cancellous bone grafting (40%). These results further attest to the refractory nature of chronic osteomyelitis.

Adult↗
PubMed1991

Complications of reamed intramedullary nailing of the tibia.

A retrospective review of 60 acute fractures of the tibia treated with reamed intramedullary nailing was undertaken to document the spectrum of complications associated with this procedure. Forty-five tibial fractures were followed to radiographic union; follow-up averaged 25 months (range, 10-63 months). Complications were categorized into intraoperative, early postoperative, and late postoperative groups. Intraoperative complications occurred in 6 of the 60 (10%) fractures and included propagation of the tibial fracture into the insertion site of the nail in four cases. In each of two other fractures, at least one of the proximal interlocking screws was documented to have poor bony purchase. These complications did not affect final fracture alignment or clinical result. Early complications included soft-tissue complications, complications of fixation, and neurologic complications. Four patients developed hematomas at the nail insertion site. Eight fractures were stabilized in greater than 5 degrees of varus or valgus. Neurologic deficits directly related to the procedure were documented in 18 patients (30%). The majority were minor sensory neuropraxias of the peroneal nerve. Sixteen (89%) of these nerve palsies were transient, resolving within 3-6 months. Two patients had persistent nerve deficits at 1-year follow-up. In the late complications group, 10 of the 45 (22%) tibial fractures followed to union developed patellar tendinitis. Nonunion developed in two fractures, both of which required additional surgical procedures to obtain fracture union. Two deep infections occurred, both of which resolved after local wound care, fracture union, and nail removal. Overall, 26 of the 45 tibial fractures available for follow-up (58%) developed some complication attributable to the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Treatment of slipped capital femoral epiphysis with a cannulated-screw technique.

Sixty patients (eighty hips) who had slipped capital femoral epiphysis were treated by epiphyseodesis with a cannulated-screw technique. Forty-nine patients (sixty-seven hips) were available for follow-up, forty-four (sixty hips) of whom were followed for a minimum of two years. Thirty-five patients (forty-six hips) were followed until the hardware was removed. Of seventy-two hips in which contrast medium was injected, arthrographic results were obtained in three. In these three hips, there was evidence of pre-existing narrowing of the joint space. Four patients (six hips) who did not have evidence of penetration by a screw or guide-wire had evidence of either pre-existing chondrolysis or osteoarthrosis. Chondrolysis did not develop postoperatively in any patient who had no evidence of it preoperatively.

Adolescent↗
PubMed1989

Rotational injury of the distal tibial physis.

Rotational displacement of the distal tibial physis occurred in a 12-year-old boy. A review of the literature indicates that long-term follow-up is necessary to determine whether premature physeal closure will occur.

Child↗
PubMedDate not supplied

Functional outcome after humeral head replacement for acute three- and four-part proximal humeral fractures.

Twenty-six hemiarthroplasties were performed for acute three- and four-part proximal humerus fractures between March 1986 and December 1991. Postoperative pain, active range of motion, and function were evaluated in 22 patients at a mean follow-up period of 30 months (range 12 to 66 months) with the American Shoulder and Elbow Surgeons evaluation form. Seventy-three percent of patients reported only slight or no pain. Active forward elevation averaged 107 degrees, external rotation averaged 31 degrees, and the average internal rotation was to the second lumbar vertebra. Strength and stability were rarely problematic. Seventy-three percent of patients reported difficulty with at least three of 15 functional tasks tested. Lifting, carrying a weight, and using the hand at or above shoulder level were the most common limitations. This study indicates that hemiarthroplasty for acute three- and four-part fractures generally can be expected to result in painfree shoulders. However, recovery of function and range of motion are much less predictable.

Aged↗
PubMedDate not supplied

Radial head fractures associated with elbow dislocations treated by immediate stabilization and early motion.

Twenty-one elbow dislocations with an associated radial head fracture were treated with immediate joint reduction, stabilization, and early range-of-motion exercises. In all cases initial treatment involved closed reduction of the ulnohumeral joint. For those cases involving minimally displaced and a few moderately displaced radial head fractures, treatment consisted of benign neglect (4 of 21). Of the more severely displaced fractures (17 of 21), 9 were treated with open-reduction internal fixation and 8 with immediate silicone head replacement. Despite radial head treatment, 6 of these cases remained unstable, prompting primary repair of collateral ligaments; 3 eventually required application of a hinged fixator as a salvage option. Results confirmed that initial radial head displacement predicts functional outcome. Our study demonstrates that fracture dislocations of the elbow demand a broad consideration of treatment options and that reconstruction of elbow stability requires either primary repair of collateral ligaments or the possible use of a hinged fixator device.

Adolescent↗
PubMedDate not supplied

Internal fixation of femoral neck fractures with posterior comminution: a biomechanical study.

OBJECTIVES: This study was performed to determine whether four cancellous lag screws provide significantly improved rigidity and fixation strength compared with three screws for fixation of displaced femoral neck fractures with posterior comminution. DESIGN: Biomechanical cadaver study. INTERVENTION: Eight pairs of mildly osteopenic femurs were selected, and each pair was fixed with three or four cancellous lag screws (randomly assigned) after the creation of a simulated femoral neck fracture with posterior comminution. A separate comparison with an unmatched group of six similar femurs with a simulated femoral neck fracture without posterior comminution and instrumented with three screws was performed to investigate the effect of posterior comminution. MAIN OUTCOME MEASUREMENT: The specimens were non-destructively tested to determine fixation rigidity in axial and anterior loading. Cyclic axial loading was then performed for 10,000 cycles; the femurs were retested for rigidity and finally were axially loaded until failure. RESULTS: The femurs with a posterior defect stabilized with three screws had significantly less resistance to axial and anterior displacement and sustained significantly lower axial loads to failure than those stabilized with four screws. The specimens instrumented with three screws without a posterior defect exhibited greater resistance to displacement in anterior loading and sustained greater axial loads to failure than those with a posterior defect stabilized with three screws. CONCLUSION: This study suggests that there are benefits to using four screws for fixation of femoral neck fractures with posterior comminution.

Biomechanical Phenomena↗
PubMedDate not supplied

The effects of nutritional status on outcome after hip fracture.

OBJECTIVE: To determine the effect of nutrition on patient outcome after hip fracture. STUDY DESIGN: Retrospective review of prospectively collected data. METHODS: Four hundred ninety hip fracture patients had albumin and total lymphocyte count levels determined at the time of admission and constituted the study population. These variables were examined as predictors for outcomes, including: in-hospital mortality, postoperative complications, hospital length of stay, hospital discharge status, one-year mortality rate, ambulatory ability, and independence in basic and instrumental activities of daily living twelve months after surgery. RESULTS: Eighty-seven patients (18 percent) were found to be malnourished on hospital admission based on a preoperative albumin level of < 3.5 grams/deciliter, and 280 patients (57 percent) based on a total lymphocyte count of < 1,500 cells/milliliter. An albumin level of < 3.5 grams/deciliter was predictive for increased length of stay (p = 0.03) and for in-hospital mortality (p = 0.03). A total lymphocyte count < 1,500 cells/milliliter was predictive for one-year mortality (p < 0.01). Patients with abnormal albumin and total lymphocyte count were 2.9 times more likely to have a length of stay greater than two weeks (p = 0.03), 3.9 times more likely to die within one year after surgery (p = 0.02), and 4.6 times less likely to recover their prefracture level of independence in basic activities of daily living (p < 0.01). Neither parameter was predictive for patients developing a postoperative complication, hospital discharge status (home versus nursing home), recovery of prefracture ambulatory ability, or independence in instrumental activities of daily living at twelve-month follow-up. CONCLUSION: Patients at risk for poor outcomes after hip fracture can be identified using relatively inexpensive laboratory tests such as albumin and total lymphocyte count.

Age Distribution↗
PubMedDate not supplied

Schuhli augmentation of plate and screw fixation for humeral shaft fractures: a laboratory study.

OBJECTIVES: Schuhli locking nuts provide a mechanism to lock 4.5-millimeter bone screws to a standard dynamic compression plate (DCP plate). It has been proposed that Schuhlis can provide increased fixation stability in areas of a proximal cortical defect or osteopenic bone and may keep screws from loosening and backing out from the plate. A biomechanical study was performed to investigate the effect of Schuhli augmentation of a ten-hole broad DCP plate for fixation of a simulated humeral shaft fracture versus standard DCP plate fixation. DESIGN: Biomechanical cadaver study. INTERVENTION: Six pairs of cadaveric humeri from elderly individuals were tested in offset axial loading, torsion, and four-point bending to obtain load versus deformation curves and baseline mechanical properties. Each pair of humeri was then instrumented with a ten-hole broad DCP plate on one side and a DCP plate augmented with Schuhlis at each screw hole on the contralateral side. All screws were placed in cortical bone. The constructs were retested in all three modalities. The humeri were then cycled in torsion for 1,000 cycles and retested in all three modalities. Each humerus was then loaded to failure in torsion to determine the ultimate load and rotational displacement. MAIN OUTCOME MEASUREMENTS: Resistance to displacement was determined from the load versus deformation curves in each testing modality before and after cycling; these data were normalized to the intact values determined prior to instrumentation. Paired Student's t tests were performed to determine statistically significant differences between the two modes of fixation. RESULTS: There were no significant differences in stability between the two fixation techniques in all three testing modalities both before and after cycling. However, the Schuhli augmented constructs sustained significantly greater loads and rotational deformations prior to failure. CONCLUSIONS: In this model of humeral shaft fractures in the elderly, the addition of Schuhlis did not significantly change the mechanical stability of plate and screw fixation. However, load and angular deformation at failure were significantly greater in the Schuhli augmented specimens.

Aged↗
PubMedDate not supplied

Effect of previous cerebrovascular accident on outcome after hip fracture.

OBJECTIVE: To evaluate the effect of previous cerebrovascular accident on outcome after hip fracture. STUDY DESIGN: Prospective, consecutive. PATIENTS: From July 1987 to March 1997, 862 community-dwelling patients sixty-five years of age or older who had sustained an operatively treated femoral neck or intertrochanteric fracture were prospectively followed. INTERVENTION: All patients had operative fracture treatment. MAIN OUTCOME MEASUREMENTS: Postoperative complications, in-hospital mortality, hospital length of stay, hospital discharge status, one-year mortality and place of residence, and return to preinjury ambulatory level, basic and instrumental activities of daily living status. RESULTS: Sixty-three patients (7.3 percent) had a history of cerebrovascular accident; the fracture was on the hemiplegic side in forty-six (86.8 percent) of the fifty-three patients with hemiplegia. Patients who had a history of cerebrovascular accident were more likely to be male and have an American Society of Anesthesiologists (ASA) rating of III or IV. They were also more likely to have three or more comorbidities, be a home ambulator, and be dependent on basic and instrumental activities of daily living before hip fracture. Hospital length of stay was significantly higher for patients who had a history of cerebrovascular accident. There were no differences in the incidence of hospital mortality or one-year mortality between patients who did and did not have a history of cerebrovascular accident before hip fracture. In addition, at one-year follow-up, when controlling for prefracture level of function, there were no differences in the rate of functional recovery between the two groups of patients. CONCLUSIONS: The functional recovery of elderly hip fracture patients who had a prior cerebrovascular accident was similar to that of patients who had no history of a prior cerebrovascular accident.

Activities of Daily Living↗
PubMedDate not supplied

Fixation of periprosthetic femoral shaft fractures: a biomechanical comparison of two techniques.

OBJECTIVE: To determine which of two currently used techniques for the treatment of periprosthetic femoral shaft fractures provides the greater fixation rigidity and strength. DESIGN: A laboratory study using six matched pairs of femurs. METHODS: Embalmed femur prosthesis constructs had a simulated periprosthetic fracture created and were fixed with a plate with proximal cables and distal bicortical screws (Ogden concept) or two allograft struts and cables. Fixation stability was compared in various loading modalities before and after cycling. They were then tested to failure. OUTCOME MEASUREMENTS: Fixation rigidity was defined as the ratio of applied load to the amount of displacement at the fracture. RESULTS: In all loading modalities, the Ogden construct was more rigid than the allograft strut fixation. The Ogden construct required 1,295 newtons for failure and the allograft strut fixation required 950 newtons (p < 0.05). CONCLUSION: The Ogden construct provided a more rigid and stronger initial fixation of a periprosthetic fracture than did the allograft construct.

Arthroplasty, Replacement, Hip↗
PubMedDate not supplied

Effect of piriformis versus trochanteric starting point on fixation stability of short intramedullary reconstruction nails.

Recently, a new, shorter IM nail using two 6 mm reconstruction screws for proximal fixation was introduced in two versions for femoral insertion: piriformis fossa (FAN) and greater trochanter (TAN). These nails were compared experimentally for their fixation stability, proximal load transmission, and failure strength in an unstable intertrochanteric fracture model in cadaveric femurs. Vertical and axial loads were first applied to the intact femurs. Fractures were created, subsequent fixation applied, and the femurs underwent a series of both vertical and axial loading tests. There was no significant difference in strain readings between the nails for either axial loading or cyclical loading. There was no statistically significant difference between the loads to failure for the trochanteric nails and the standard antegrade nails. The average ultimate loadfor the FAN and TAN nails were 3010 N and 2830 N respectively. These two nails performed very similarly throughout our testing.

Biomechanical Phenomena↗
PubMedDate not supplied

The effect of screw type on the fixation of depressed fragments in tibial plateau fractures.

The ability of various screw types to stabilize depressed tibial plateau fractures was determined in a biomechanical study using a Sawbones model. Two sizes of both cancellous and cortical screws were evaluated for both supportfrom below and through the depressed fragment. As a general trend, cancellous bone screws provided a greater resistance to fragment displacement than cortical bone screws, and screws with a smaller thread diameter provided greater resistance to displacement than screws of the same thread type with a larger diameter. These results agree with the accepted standard that cancellous screws provide better fixation for tibial plateau fractures, but also are counterintuitive in that smaller screws provided greater fixation than larger screws of the same type.

Analysis of Variance↗
PubMedDate not supplied

The effect of distal screw orientation on the intrinsic stability of a tibial intramedullary nail.

To compare the intrinsic stability of two distal interlocking screw orientations for tibial nailing of distal third tibial diaphyseal fractures without isthmal support, six Depuy (Warsaw, Indiana) tibial intramedullary nails were implanted in simulated distal tibiae. The constructs received both two parallel (medial to lateral) and two perpendicular (one medial to lateral, one anterior to posterior) distal interlocking screws in a random order Angular, translational, and torsional displacements of the nails were measured in response to 70 N proximal applications of anterior, posterior, medial, and lateral loads, and a 7.7 Newton-meter torsional load. There were no differences in medial or lateral angulations between the screw orientations (average: 2.5 degrees, p > 0.8). Angulation in the sagittal plane (anterior and posterior) was slightly less for parallel screw fixation (1.6 degrees versus 2.4 degrees), but this was not statistically significant (p > 0.1). Rotational angulation was higher in the parallel (average: 9.9 degrees) versus the perpendicular (average: 8.1 degrees) screw orientation, but these results were not statistically significant (p > 0.1). Pure translation did not occur in either the parallel or perpendicular screw orientations. These results indicate that fixation stability of these tibial intramedullary nails is not significantly influenced by distal interlocking screw orientation in response to sagittal, coronal, or rotational forces.

Bone Nails↗
PubMedDate not supplied

Soft-tissue principles for orthopaedic surgeons.

Meticulous handling of the tissues, reversal of known patient risk factors, and attention to detail can avoid many soft-tissue complications. Prompt management or consultation of a soft-tissue expert may reduce the morbidity and need for extensive reconstructive procedures.

Humans↗
PubMedDate not supplied

Robotics and computer-assisted orthopaedic surgery.

These are just a few representative applications of the synergistic use of computer and robotic technology assisting the orthopaedic surgeon. While the individual systems are certain to change over time, the basic principles of correlating radiographic and anatomic data through a registration process, and displaying additional instrument or implant information through smart tools and surgical navigation are certain to become an increasingly important aspect of joint arthroplasty, deformity correction, and spinal and trauma surgery. Only the orthopaedic surgeon who clearly understands the goals, applications, and limitations of these systems can decide which are appropriate for his patients, his hospital, and his practice. Determining the cost and time benefits, both before and after an obligatory "learning curve" requires a complex interaction of capital investments, time savings, and outcome research on both safety and efficacy issues. The orthopaedist who understands and applies these technologies will help his patients to achieve the best possible care. Excellent resources in the literature on this topic include the September, 1998, issue of Clinical Orthopaedics and Related Research, a symposium on "Computer-Assisted Orthopaedic Surgery: Medical Robots and Image Guided Surgery"; Guest editor, Anthony M. DiGioia, III, MD. Also, the January, 2000, issue of Operative Techniques in Orthopaedics, "Medical Robotics and Computer-Assisted Orthopaedic Surgery. Guest editors: Anthony M. DiGioia, III, M.D. and Branislav Jaramaz, Ph.D. Additional Internet based information is available from the Journal of Computer Aided Surgery (formerly: Journal of Image Guided Surgery), at http://journals.wiley.com/.

Arthroplasty, Replacement, Hip↗