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Biomedical subjects

Mark R Brinker

Publications and source records attributed to Mark R Brinker.

16 recordsLinked to original sources
PubMed2007

Exchange nailing of ununited fractures.

Exchange nailing is most appropriate for a nonunion without substantial bone loss. There is no clear consensus regarding the use of exchange nailing in the presence of active, purulent infection. The exchange nail should be at least 1 mm larger in diameter than the nail being removed, and it has been recommended that it be up to 4 mm larger when the nail being removed was greatly undersized. Canal reaming should progress until osseous tissue is observed in the reaming flutes. Exchange nailing is an excellent choice for aseptic nonunions of noncomminuted diaphyseal femoral fractures, with union rates reported to range from 72% to 100%. On the basis of the available literature, exchange nailing cannot be recommended for distal femoral nonunions at this time. Exchange nailing is an excellent choice for aseptic nonunions of noncomminuted diaphyseal tibial fractures, with union rates reported to range from 76% to 96%. On the basis of the available literature, exchange nailing is generally not indicated for humeral nonunions.

Ankle Injuries↗
PubMed2006

Payer type has little effect on operative rate and surgeons' work intensity.

Does health-care payer type affect the rate of operative treatment and surgeons' work intensity for patients with orthopaedic conditions? We analyzed the clinical and financial data collected during 6 consecutive years (1999-2004) for a group practice of 40 orthopaedic surgeons. We examined the rate of operative treatment and surgeons' work intensity (total physician's work Resource-based Relative Value System units) by diagnosis, patient age, and payer type. The eight payer types were: capitation health maintenance organization, health maintenance organization, preferred provider organization, indemnity, self-pay, Workers' Compensation, Medicaid, and Medicare. There were 230,306 patients with 526 unique primary diagnoses. Diagnosis accounted for most of the variability in operative rates and surgeons' work intensity. After adjusting for differences attributable to diagnosis, payer type had little effect on the rate of operative treatment and surgeons' work intensity.

Adult↗
PubMed2004

Utilization of orthopaedic services for hand and wrist conditions in a capitated population.

BACKGROUND: The utilization of orthopaedic services (office visits and surgery) to treat hand and wrist conditions is not well known. In this study, we report the utilization rates for patients referred for orthopaedic treatment of hand and wrist conditions in a large population of individuals enrolled in a capitated insurance plan. METHODS: The study population consisted of individuals enrolled, between January 1998 and December 2001, in a capitated insurance plan that had an annual average membership of 135,188 during that period. This plan was serviced by an independent physician association of sixty-two orthopaedic surgeons who were responsible for all orthopaedic care. Data were collected prospectively in a centralized database as patients with various hand or wrist conditions were referred for orthopaedic services. Odds ratios were used to compare gender-specific and age-specific utilization rates. RESULTS: Overall utilization rates were 18.06 office visits and 6.47 surgical procedures per 1000 members per year. The most frequent hand or wrist conditions were fractures, carpal tunnel syndrome, tendinitis or tenosynovitis, and ganglion or synovial cysts. These four diagnoses accounted for 70% of all office visits and 71% of all surgical cases. Across all age groups, males had a significantly higher rate of utilization of office visits (p < 0.001). Between the ages of thirty-five and fifty-five years, utilization of office visits and surgery increased approximately linearly with age. CONCLUSIONS: A comparison of these data with those of previous reports indicates that approximately one of every ten patients who are referred for orthopaedic services has a hand or wrist condition, and nearly half will require surgery.

Adolescent↗
PubMed2004

The incidence of fractures and dislocations referred for orthopaedic services in a capitated population.

BACKGROUND: The purpose of this study was to determine the annual incidence rates of non-work-related traumatic fractures and dislocations (excluding head and facial injuries) referred for orthopaedic services in a large population enrolled under a capitated insurance contract. METHODS: The number of fractures and dislocations that were referred for orthopaedic services were recorded prospectively from among an average of 135,333 persons per year who were enrolled under a capitated insurance contract during the three-year study period. These data were used to determine the gender-specific and age-specific incidence rates of fractures and dislocations referred for orthopaedic services. RESULTS: A total of 3440 fractures and 422 dislocations were referred for orthopaedic services during the three-year study period. The incidence rate of fractures referred for orthopaedic services was 8.47 per 1000 member-years, with a significantly (p < 0.0001) higher rate among males. Members between the ages of ten and fourteen years had the highest rate of fractures referred for orthopaedic services (21.52 per 1000 member-years). The lifetime risk of a traumatic fracture referred for orthopaedic services to the age of sixty-five years was one in two for both males and females. The incidence rate of dislocations referred for orthopaedic services was 1.04 per 1000 member-years, which did not differ significantly (p = 0.75) between genders. Members between the ages of fifteen and nineteen years had the highest rate of dislocations referred for orthopaedic services (2.75 per 1000 member-years). The lifetime risk of a traumatic dislocation referred for orthopaedic services to the age of sixty-five years was one in sixteen for both male and female members. CONCLUSIONS: Young males had the highest rate of traumatic fractures referred for orthopaedic services. Adolescents of both genders had high rates of traumatic dislocations referred for orthopaedic services. The lifetime risk of a non-work-related fracture referred for orthopaedic services to the age of sixty-five years is approximately equal to that of coronary artery disease.

Adolescent↗
PubMed2004

Bilateral femoral neck fractures after pelvic irradiation.

Our patient, who had no history of trauma, developed bilateral femoral neck fractures several years after pelvic irradiation. The well-documented sequelae of femoral neck fractures include avascular necrosis, nonunion, and malunion. Postirradiation pelvic pain, particularly in the absence of trauma, should be aggressively evaluated. With high clinical suspicion and normal plain radiographs, MRI can be used to exclude potentially serious fractures.

Aged↗
PubMed2004

Ilizarov correction of malrotated femoral shaft fracture initially treated with an intramedullary nail: a case report.

Ideally, acquired femoral malrotation as a complication of intramedullary nailing of a femoral shaft fracture should be identified and corrected early in the course of treatment. In this report, we present a previously undescribed precise surgical technique for acutely correcting an acquired femoral malrotation deformity 20 days after fixation of a femoral shaft fracture with a statically locked intramedullary nail. An llizarov external fixator was used intraoperatively to correct a 27 degree femoral malrotation deformity in a 19-year-old man.

Adult↗
PubMed2003

Patellar tracking during simulated quadriceps contraction.

The current study compared patella tracking during simulated concentric and eccentric quadriceps contractions in 12 knees from cadavers using a three-dimensional electromagnetic tracking system. The patella shifted (translated) and tilted medially during approximately the initial 22 degrees tibiofemoral flexion. The patella then shifted and tilted laterally for the remaining arc of tibiofemoral flexion (90 degrees). At 90 degrees tibiofemoral flexion, the patella had an orientation of lateral patella shift and lateral patella tilt. Patella shift was significantly more lateral between 40 degrees and 70 degrees tibiofemoral flexion during concentric quadriceps action than during eccentric contraction. Patella tilt was significantly more lateral between 45 degrees and 55 degrees tibiofemoral flexion during concentric quadriceps contraction than during eccentric action. No other significant differences were seen between the quadriceps contraction conditions. The current study supports the hypothesis that patellar instability is most likely a result of various anatomic and physiologic factors causing a failure of the extensor mechanism to deliver the patella into the femoral sulcus and that a patellar dislocation rarely would occur in a normal knee.

Biomechanical Phenomena↗
PubMed2003

Bone realignment with use of temporary external fixation for distal femoral valgus and varus deformities.

BACKGROUND: Correction of a distal femoral deformity may prevent or delay the onset of osteoarthritis or mitigate its effects. Accurate correction of deformity without production of a secondary deformity depends on precise localization and quantification of the deformity. We report a technique to correct distal femoral deformities in the coronal plane. METHODS: Fourteen femora in thirteen skeletally mature patients with a distal femoral deformity underwent operative reconstruction. The preoperative deviation of the mechanical axis ranged from 90 mm laterally (genu valgus) to 120 mm medially (genu varus). The mechanical lateral distal femoral angle was abnormal in all fourteen knees. The technique consisted of application of an external fixator, performance of a percutaneous distal femoral dome osteotomy, correction of the deformity, and locking of the external fixator. A statically locked retrograde intramedullary nail was inserted following reaming, and the external fixator was removed. The mean duration of follow-up was thirty-three months (range, six to forty-seven months). RESULTS: The mean time until healing was thirteen weeks (range, six to thirty-nine weeks). Nine of the thirteen patients reported an improvement in walking, and none needed an assistive device. All nine patients with preoperative knee pain were free of tibiofemoral pain at the most recent follow-up evaluation. The mechanical lateral distal femoral angle was within the normal range in twelve of the fourteen knees. The mechanical axis was within the normal range in ten lower extremities. In three of the four remaining limbs, the residual abnormal deviation of the mechanical axis was due to a residual tibial deformity. CONCLUSIONS: Percutaneous dome osteotomy combined with temporary external fixation and insertion of an intramedullary nail can correct distal valgus and varus femoral deformities. We attributed the early mobilization of patients and the rapid bone-healing to the limited soft-tissue dissection, the low-energy corticotomy, and the use of intramedullary fixation in our surgical technique.

Activities of Daily Living↗
PubMed2002

Preoperative health status of patients with four knee conditions treated with arthroscopy.

Normative preoperative Short Form-12 Health Survey components summary scores have not been reported for patients who have knee conditions treated with arthroscopy. During one calendar year, 269 consecutive patients with a knee injury (119 meniscus lesions, 73 anterior cruciate ligament ruptures, 54 articular cartilage lesions, and 23 with patellar instability) completed the Short Form-12 Health Survey before medical evaluation. Mental Component Scale and Physical Component Scale scores were computed. Scores were compared with previously published normative and age-specific data for several medical conditions and the United States general population. With the number of patients available, no significant differences were detected between knee conditions for the Mental Component Scale and Physical Component Scale scores. In general, Physical Component Scale scores among patients with knee conditions were similar to previously reported Physical Component Scale scores for patients with orthopaedic shoulder conditions and significantly lower than the United States population norms. These data can be used as historic control groups to represent patients with knee conditions requiring arthroscopy. Age-specific Mental Component Scale and Physical Component Scale scores are indicated when comparing groups with a limited age range.

Adult↗
PubMed2002

The effect of payer type on orthopaedic practice expenses.

BACKGROUND: Orthopaedic practice expenses are the costs associated with providing treatment that are incurred by a physician's practice. Certain payer types are thought to increase orthopaedic practice expenses by increasing paperwork and other administrative activities. Our study investigated the hypothesis that orthopaedic practice expenses would vary significantly by payer type. METHODS: With use of the method of activity-based costing, data on the orthopaedic practice expenses for 518 consecutive patients (286 men and 232 women) who had a sports-related knee condition were collected. For each patient enrolled in the study, all employees recorded the actual amount of time that they spent on each of seventeen specific activities previously shown to be associated with orthopaedic practice. The seventeen activities were categorized as either a value-added activity, which adds value to the services provided to the patient, or a nonvalue-added activity, which does not add value. The total orthopaedic practice expense was the sum of the value-added and nonvalue-added activity expenses. To capture all practice expenses associated with a particular episode of care, data collection continued until the patient was discharged and the financial account had been settled. We evaluated the differences in orthopaedic practice expenses among six payer types: self-pay, indemnity plan, Medicare, health maintenance organization/point-of-service plan (HMO/POS), preferred provider organization (PPO), and Workers' Compensation. RESULTS: The differences among payer types with respect to orthopaedic practice expenses were significant (p = 0.0000000004). The total orthopaedic practice expense per episode of care was $123 for self-pay, $195 for an indemnity plan, $148 for Medicare, $178 for PPO, $208 for HMO/POS, and $299 for Workers' Compensation. These differences among payer types persisted even after accounting for patient age, gender, treatment type (nonoperative versus operative), and number of office visits. Nonvalue-added activity expenses differed to a greater degree among the payer types than did value-added activity expenses. CONCLUSIONS: The payer type was found to be an important factor affecting orthopaedic practice expenses, particularly with respect to nonvalue-added activity expenses.

Adult↗
PubMed2002

Utilization of orthopaedic services in a capitated population.

BACKGROUND: The utilization rate for orthopaedic services (office visits and surgery) is not well known. The purpose of this study was to determine the utilization rates for orthopaedic office visits and surgical procedures in a large population of captured lives. METHODS: The study population comprised an average of 134,902 persons per month who were enrolled under a capitated insurance plan between January 1999 and December 1999. This plan was serviced by an independent physician association of sixty-two orthopaedic surgeons who were responsible for all orthopaedic care. Data were collected prospectively and stored in a centralized database. All analyses were conducted with use of monthly averages. Poisson regression was used to compare utilization rates and to calculate odds ratios in order to determine whether the utilization rates varied by age and gender. RESULTS: The highest proportions of office visits were due to fractures (21%), osteoarthritis (4%), meniscal tears (4%), and low-back pain or sciatica (4%). Knee arthroscopy (30%), foot and ankle procedures (10%), and spine procedures (9%) accounted for the highest proportions of surgical procedures. The overall utilization rates were 6.96 office visits and 1.99 surgical procedures per 1000 covered lives per month. Across all age groups, males and females did not differ with respect to the utilization rate for office visits (p = 0.42) or surgery (p = 0.09). Increased age was significantly related to increased utilization rates for office visits (p < or =0.0002) and surgery (p < or = 0.002). CONCLUSIONS: These data may be used to determine the size of a capitated population that an orthopaedic practice can accommodate, to determine the number of orthopaedic providers that is needed to provide services for a capitated population, and to estimate the expenses associated with providing orthopaedic services for a capitated population in an orthopaedic practice.

Adolescent↗
PubMedDate not supplied

An examination of bias in shoulder scoring instruments among healthy collegiate and recreational athletes.

This investigation examined whether gender, activity level, hand dominance, or age displayed bias for 5 common shoulder scores among 120 healthy collegiate or recreational athletes. Data were collected for 5 instruments: Constant-Murley, UCLA rating, pre-1994 American Shoulder and Elbow Surgeons, Shoulder Pain and Disability Index, and Oxford. Normalized total and subscale scores and effect sizes were analyzed to determine how each demographic variable affected the scores. The normalized scores for the 5 instruments were not equivalent. The normalized total scores were significantly lower for the Constant-Murley score (P <.0001) compared with those for the other instruments. Men had significantly higher Constant-Murley scores, primarily because of the strength subscale. The Constant-Murley score also displayed gender and age biases. The other instruments had mostly negligible variance attributable to gender, activity level, hand dominance, or age. In the absence of a universal validated method, shoulder scoring instruments should be carefully chosen to match the population and the purpose of the study.

Adolescent↗
PubMedDate not supplied

Ilizarov compression over a nail for aseptic femoral nonunions that have failed exchange nailing: a report of five cases.

OBJECTIVE: To evaluate a new operative treatment of femoral nonunion following failed exchange nailing. DESIGN: Retrospective review, consecutive series. SETTING Office-based orthopaedic practice. PATIENTS: Five consecutive patients (ages 31-67 years) were referred in with a femoral nonunion following exchange nailing an average of 28 months (range 11-55) after the initial traumatic injury. The patients had undergone an average of 5 (range 2-8) previous surgeries on the femur. No patient had signs or history of bone infection or segmental bone loss at presentation. All patients had diaphyseal or diaphyseal-metaphyseal oligotrophic nonunions and had failed an average of 2 (range 1-3) previous exchange nailings. INTERVENTION: Slow compression (0.25 to 0.50 mm per day) of the nonunion site over a new, smaller diameter nail using an Ilizarov external fixator. MAIN OUTCOMES MEASUREMENTS: Clinical and radiographic evidence of bone union, ambulation, pain, residual deformity, or shortening. RESULTS: All nonunions healed without the need for further nonunion surgery. The external fixator was removed at an average of 133 days (range 86-238 days). No deep infections occurred in any patient. All patients experienced some degree of pin site irritation. At the most recent follow-up (average 45 months; range 12-75 months), all patients had improved their functional ambulatory status and had discontinued or decreased the use of assistive devices to walk. All patients were full weight bearing. Average pain, as rated on a 0 to 10 Visual Analogue Scale, decreased from 8 of 10 before treatment to 1 of 10 after treatment. No patient experienced a clinically significant worsening of leg length discrepancy. CONCLUSIONS: Slow compression over an intramedullary nail using external fixation successfully promotes the healing of problematic femoral nonunions that have failed one or more prior exchange nailings.

Adult↗
PubMedDate not supplied

The effects of femoral shaft malrotation on lower extremity anatomy.

OBJECTIVE: To determine how axial rotation around the anatomic axis of the femur, as would occur with malrotation of a femoral fracture, affects frontal and sagittal plane alignment and knee joint orientation. DESIGN: Computer-generated models of the lower extremity were constructed using standardized dimensions. To simulate a malrotated fracture, these models were rotated in the shaft around the anatomic axis in 15 degrees increments from 60 degrees internal to 60 degrees external rotation. Rotation was performed at the proximal fourth, mid-shaft, and distal fourth. MAIN OUTCOME MEASUREMENTS: At each rotational position, the mechanical axis deviation in millimeters and the changes in mechanical lateral distal femoral angle in degrees were measured to quantify frontal plane malalignment and malorientation, respectively. The mechanical axis deviation in millimeters in the sagittal plane was also measured at each rotatory position. RESULTS: Femoral shaft malrotation greater than 30 degrees internal rotation of a subtrochanteric fracture or more than 45 degrees of a midshaft fracture or external rotation of 30 degrees or greater of a supracondylar fracture resulted in frontal plane malalignment. External rotation of a supracondylar fracture of 45 degrees or more results in knee joint malorientation. Any external rotation at all 3 fracture levels caused posterior displacement of the weight-bearing axis in the sagittal plane. CONCLUSIONS: Malrotation of a femoral shaft fracture is not just a cosmetic problem. Internal and external rotation causes malalignment and malorientation in the frontal plane, depending on the level of the fracture and the magnitude of malrotation. External rotation of any degree at the proximal fourth, mid-shaft, and distal fourth causes a posterior shift of the weight-bearing axis in the sagittal plane.

Biomechanical Phenomena↗