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Biomedical subjects

K J Koval

Publications and source records attributed to K J Koval.

At least 19 recordsLinked to original sources
PubMed1998

Postoperative weight-bearing after a fracture of the femoral neck or an intertrochanteric fracture.

Sixty patients who had had operative treatment of a fracture of the femoral neck or an intertrochanteric fracture were allowed to bear weight as tolerated on the injured limb. The average age was seventy-seven years. Computerized gait-testing was performed at one, two, three, six, and twelve weeks postoperatively to quantify weight-bearing. For the purpose of analysis, the patients were divided into three groups according to whether they had internal fixation of a stable fracture, internal fixation of an unstable fracture, or a primary hemiarthroplasty. Thirty-two patients completed the entire twelve-week study. The average amount of weight that these patients placed on the injured limb increased progressively with time. The average load supported by the injured limb was 51 per cent that of the uninjured limb at one week, and it gradually increased to 87 per cent at twelve weeks. During the first three weeks, the patients who had had internal fixation bore substantially less weight than those who had had a hemiarthroplasty. By six weeks, we could detect no significant differences, with the numbers available, among the groups with regard to weight-bearing or other measured gait parameters. We concluded that elderly patients who are allowed to bear weight as tolerated after operative treatment of a fracture of the femoral neck or an intertrochanteric fracture appear to voluntarily limit loading of the injured limb.

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PubMed1998

Effect of acute inpatient rehabilitation on outcome after fracture of the femoral neck or intertrochanteric fracture.

A study was performed to assess the impact of intensive inpatient rehabilitation on the outcome after a fracture of the femoral neck or an intertrochanteric fracture. Before 1990, our hospital did not have an inpatient rehabilitation program. On January 1, 1990, a diagnosis-related-group-exempt (DRG-exempt) acute rehabilitation program was initiated. Patients were discharged to this program after evaluation by a staff physiatrist. Before 1990, twenty-seven (9.0 per cent) of 301 patients were discharged to an outside rehabilitation facility. After January 1990, the percentage of patients who were discharged to the DRG-exempt program increased yearly, from nineteen (17 per cent) of 113 patients in 1990 to forty-one (64 per cent) of sixty-four patients in 1993; this difference was significant (p < 0.01). Before 1990, the average duration of the stay in the hospital was 21.9 days. After January 1990, the average duration for the patients who did not enter the rehabilitation program was 20.0 days whereas the average duration for those who did was 31.4 days (16.1 days for acute care and 15.6 days for the rehabilitation program). There were no differences in the hospital discharge status or in the walking ability, place of residence, need for home assistance, or independence in basic and instrumental activities of daily living at the six and twelve-month follow-up examinations between patients who had been managed before initiation of the rehabilitation program and those managed after it or between patients who had been discharged to this program after its initiation and those who had not. These results raise serious questions regarding the global cost-effectiveness of these programs for patients who have had a fracture of the femoral neck or an intertrochanteric fracture.

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PubMed1998

The Medoff sliding plate and a standard sliding hip screw for unstable intertrochanteric fractures: a mechanical comparison in cadaver femurs.

The Medoff sliding plate has a dual side capability along both the femoral shaft and neck to increase theoretically interfragmentary compression and load-sharing in hip fractures. We studied intertrochanteric fracture fixation in cadaveric bone to determine whether this device has a mechanical advantage over a standard sliding hip screw. 2-part and 4-part fractures were created in 12 cadaver femurs. The fractures were fixated and sequentially destabilized; bone and plate strains and fragment displacements were determined during testing, as a function of applied physiological loads before and after short-term cycling. The Medoff sliding plate imposed a higher mean medial cortex strain than the sliding hip screw in all fracture models and at all loading levels, and the difference was statistically significant in the 2-part and in the unstable 4-part fracture models. The loading of the medial cortex region after cycling was approximately 50% higher in the Medoff samples than in the sliding hip screw samples. There were no significant differences in plate strains, fracture displacements or load to failure between the 2 devices. These observations favor the dual sliding principle as regards providing fracture compression and load-sharing, which may explain low failure rates in clinical series of unstable intertrochanteric fractures, treated with the Medoff sliding plate.

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PubMed1998

Circumstances of falls causing hip fractures in the elderly.

A prospective analysis was performed on 832 patients to determine the circumstances surrounding falls leading to hip fracture within a homogeneous, elderly urban population. Special emphasis was placed on the season of year, time of day, location of fall, and other circumstances in which the fracture occurred. All patients were community dwelling, cognitively intact, previously ambulatory elderly who sustained a femoral neck or intertrochanteric fracture. Most fractures occurred at home, particularly in patients who were older, less healthy, and poorer ambulators. More than 75% of fractures resulted from a fall while the patient was standing or walking. Most falls occurred during daylight hours with a peak seen in the afternoon. No seasonal variation in the incidence of hip fractures was observed.

Accidental Falls↗
PubMed1998

Predictors of functional recovery after hip fracture in the elderly.

Three hundred thirty-eight community dwelling, ambulatory, elderly patients who sustained a hip fracture were observed prospectively to determine which patient and fracture characteristics at hospital admission predicted functional recovery at 3, 6, and 12 months. Multiple logistic regression was performed to estimate the simultaneous contributions of the predictor variables to failure of functional recovery. Before sustaining a fracture, 16% of patients were dependent on basic activities of daily living and 46% were dependent on instrumental activities of daily living. By 1 year after fracture, 73% of the patients had recovered to their basic activities of daily living status before fracture whereas only 48% had recovered to their instrumental activities of daily living status before fracture. Patients who were age 85 years or older, who lived alone before sustaining a fracture, and who had one or more comorbidities were at increased risk of delay or failure in recovering basic activities of daily living. Only instrumental activities of daily living independence before fracture predicted failure to recover instrumental activities of daily living function by 3 and 6 months after fracture. At 1 year, patient age 85 years or older was the only predictor of failure to recover instrumental activities of daily living function that existed before fracture. Based on characteristics at admission, a group of patients at high risk for failure to recover basic activities of daily living function within 1 year of sustaining a hip fracture can be identified.

Activities of Daily Living↗
PubMed1998

Functional outcome after hip fracture. Effect of general versus regional anesthesia.

The effect of anesthetic technique on ambulation and functional recovery after hip fracture was studied in a series of 631 community dwelling, elderly patients. Functional recovery at followup was determined by an 11-item functional rating scale. In univariate analysis, recovery of ambulatory ability and percent functional recovery were significantly higher at 6 months for patients who had general anesthesia. When controlling for potential confounding variables, however, no differences were observed in recovery of ambulatory ability or percent functional recovery between the two groups at 3, 6, or 12 months after hip fracture.

Activities of Daily Living↗
PubMed1998

Stress fractures of the femoral neck.

Stress fractures of the femoral neck are uncommon injuries. In general these injuries are seen in two distinct populations: (1) young, healthy, active individuals such as recreational runners, endurance athletes, or military recruits; and (2) the elderly who have osteoporosis. Stress fractures can be classified as either fatigue or insufficiency fractures and result from untoward cyclic loading or impaired bone quality. The key to treatment is early diagnosis, which may require scintigraphy or magnetic resonance imaging. Nondisplaced compression type stress fractures can be treated nonoperatively with protected weight-bearing and frequent radiographic followup. Tension type stress fractures should be stabilized internally to prevent the adverse consequences of fracture displacement.

Age Factors↗
PubMed1998

Hip fracture prevention: a review.

The incidence of hip fractures worldwide is expected to almost quadruple in the next 60 years. Increased cost-containment pressures will focus attention not only on improvements in hip fracture treatment but also on prevention. Three approaches that can prevent hip fractures--preventing falls, preventing and treating bone fragility, and using external hip protectors--are reviewed. Although it is impossible to prevent all hip fractures, these methods may significantly reduce the annual incidence of these fractures.

Accidental Falls↗
PubMed1997

Pubic rami fracture: a benign pelvic injury?

OBJECTIVE: To present a consecutive series of older patients with pubic rami fractures and evaluate their long term functional outcome. STUDY DESIGN: Retrospective. METHODS: Sixty-three consecutive community-dwelling, ambulatory patients who sustained a public rami fracture and were treated at one hospital were reviewed. Fifty-two of sixty-three patients (83%) had radiographic evidence of pubic rami fracture at initial presentation; in the remaining eleven patients, the diagnosis of pubic rami fracture was made after additional imaging studies. Sixty patients (95%) required hospitalization for pain control and progressive mobilization. RESULTS: The hospital length of stay for the sixty admitted patients averaged fourteen days; patients who had three or more associated medical comorbidities or required use of a cane or walker for ambulation prior to fracture were more likely to have been hospitalized greater than two weeks. Thirty-eight patients were available for one year minimum follow-up; thirty-five of thirty-eight patients (92%) were living at home, 84% had no or mild complaints of hip/groin pain, 92% had returned to their prefracture ambulatory status, and 95% had returned to their performance function in activities of daily living. CONCLUSIONS: 1) Elderly patients with pubic rami fractures utilize substantial healthcare resources based upon length of stay and need for home care services; and 2) those patients who survive have a good prognosis with regard to long term pain relief and functional outcome.

Activities of Daily Living↗
PubMed1997

A new technique for complex fibula fracture fixation in the elderly: a clinical and biomechanical evaluation.

OBJECTIVE: To determine whether intramedullary fixation could augment plate fixation strength in comminuted and osteopenic fibula fractures. STUDY DESIGN: Retrospective clinical study and biomechanical laboratory study. METHODS: Twenty comminuted or osteopenic fibula fractures in twenty patients age fifty years or older were stabilized using plate fixation augmented with intramedullary Kirschner wires. Nineteen patients were available for follow-up which averaged 15.4 months (range, 6-43 months). In conjunction with this clinical series, a biomechanical evaluation was performed comparing fixation of mildly osteopenic fibulas using this technique to plate and screws alone. The fibulas were first tested non destructively in bending, and then destructively in torsion to determine stability and ultimate strength of the fixation. RESULTS: All nineteen fractures united without loss of reduction: seventeen of nineteen patients (89%) had either no pain, slight or mild pain. Biomechanical testing demonstrated that the resistance to bending of the plated fibulas augmented with Kirschner wires was 81% greater than the fibulas stabilized with a plate alone (p < .05). In torsional testing, the augmented group had twice the resistance to motion than the plate group (p < .002). CONCLUSION: This clinical series and biomechanical study support the use of plate fixation augmented with intramedullary Kirschner wires for the treatment of comminuted and osteopenic fibula fractures in the elderly.

Aged↗
PubMed1997

Hip fractures in the elderly: predictors of one year mortality.

OBJECTIVE: To determine the one year mortality following hip fracture in an ambulatory, community dwelling, cognitively intact elderly population and to examine the role of specific type, number, and severity of associated medical comorbidities. DESIGN: Prospective, consecutive. METHODS: Six hundred twelve elderly who sustained a non-pathologic hip fracture were followed. RESULTS: Twenty-four patients (4%) died during hospitalization; seventy-eight (12.7%) died within one year of fracture. The factors that were predictive of mortality, based on multivariate analysis, were patient age > 85 years, preinjury dependency in basic activities of daily living, a history of malignancy other than skin cancer, American Society of Anesthesiologists rating of operative risk 3 or 4, and the development of one or more in-hospital postoperative complications; all factors other than the development of an in-hospital complication were independent of treatment. CONCLUSION: These results indicate that efforts at reducing one year mortality after hip fracture should be directed at the prevention of postoperative complications.

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PubMed1997

Use of the Medoff sliding plate for subtrochanteric hip fractures.

OBJECTIVE: To evaluate the effects of dynamization of a sliding hip screw plate on the fixation stability for several types of subtrochanteric fractures. Clinical results of treating reverse oblique fractures occasionally show medialization of the femoral shaft. DESIGN: Two types of plate dynamization were compared using the same test protocol in identically prepared groups of uniform, artificial femurs. METHODS: Sawbones composite femurs (Pacific Research Labs, Vashon, WA) having five orientations of simulated subtrochanteric fractures were used with the Medoff plate (Medpac, Inc., Valencia, CA) either fully dynamized or with the sliding lag screw locked. These specimens were physiologically loaded and cycled and displacements of the proximal femur determined. RESULTS: Significantly more shaft medialization occurred with reverse oblique fracture patterns when the Medoff plate was fully dynamized. CONCLUSION: Clinical treatment of reverse oblique fractures with the Medoff plate should be performed using the lag screw locked and only the plate dynamized.

Bone Plates↗
PubMed1997

Does blood transfusion increase the risk of infection after hip fracture?

OBJECTIVE: To determine whether allogeneic red blood cell transfusion is a predictor for developing an in-hospital postoperative urinary tract, respiratory, or wound infection. STUDY DESIGN: Prospective, consecutive. METHODS: Six hundred eighty-seven community-dwelling, ambulatory, geriatric hip fracture patients were prospectively followed; all patients had operative fracture treatment and received perioperative antibiotics. RESULTS: Sixty-eight patients had a culture-positive infection before operative treatment. One hundred thirty-four of the remaining 619 patients (21.6%) developed a postoperative infection, primarily a urinary tract infection. The infection rate was 26.8% in transfused patients compared with 14.9% in nontransfused patients (p = 0.001). When stratifying by the type of infection, only the risk of urinary tract infection was statistically significant (p = 0.001). After controlling for the effect of patient age, sex, number of preinjury medical comorbidities, American Society of Anesthesiologists (ASA) rating of operative risk, fracture type, surgical delay, type of surgery, type of anesthesia, operative time, and blood loss, the relationship between allogeneic red blood cell transfusion and postoperative urinal tract infection remained statistically significant. CONCLUSIONS: Geriatric hip fracture patients who receive allogeneic red blood cell transfusions are at higher risk for developing a postoperative urinary tract infection than are those patients who are not transfused.

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PubMed1997

Distal femoral fixation: a biomechanical comparison of the standard condylar buttress plate, a locked buttress plate, and the 95-degree blade plate.

OBJECTIVES: This biomechanical cadaver study was performed to compare the fixation stability of a standard lateral condylar buttress plate with a similar condylar buttress plate with the distal screws locked to the plate. Then the study was repeated with six additional matched femoral pairs to compare the locked plate with a standard 95-degree blade plate. DESIGN: Six matched pairs of mildly osteopenic femurs were selected, and each side was assigned randomly to fixation with either a standard lateral condylar buttress plate or a modified lateral condylar buttress plate with locked distal screws. The experiment was repeated with six additional matched pairs of femurs instrumented with either a modified lateral condylar buttress plate with locked distal screws or a standard 95-degree blade plate. INTERVENTION: The femurs were instrumented, and a gap osteotomy was created at the distal femoral metaphysis. The instrumented femurs were then mechanically tested in axial compression and bending/torsional loading to determine fixation stability; then they were loaded at 1,000 newtons for 10(5) cycles and retested for stability. MAIN OUTCOME MEASUREMENT: The displacement across the osteotomy gap at 100-newton and 1,000-newton axial loads was measured directly for each specimen before and after cycling. In addition, resistance to displacement in bending/torsional loading (newtons/centimeter) was determined from load/displacement curves, before and after cycling. RESULTS: The locked buttress plate provided significantly greater fixation stability than the standard plate both before and after cycling in axial loading. The locked buttress plate also proved significantly more stable in axial loading than the blade plate both before and after cycling. CONCLUSION: A condylar buttress plate with locked screws is a valid concept for improving fixation stability.

Biomechanical Phenomena↗
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.

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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↗