Prioritizing Research Informing Antibiotic Prophylaxis Guidelines for Knee Arthroplasty Patients.

INTRODUCTION: Guidelines for routine antibiotic prophylaxis (AP) before dental procedures to prevent periprosthetic joint infection (PJI) have been hampered by the lack of prospective clinical trials. OBJECTIVES: To apply value-of-information (VOI) analysis to quantify the value of conducting further clinical research to reduce decision uncertainty regarding the cost-effectiveness of AP strategies for dental patients undergoing total knee arthroplasty (TKA). METHODS: An updated decision model and probabilistic sensitivity analysis (PSA) evaluated the cost-effectiveness of AP and decision uncertainty for 3 AP strategies: no AP, 2-y AP, and lifetime AP. VOI analyses estimated the value and cost of conducting a randomized controlled trial (RCT) or observational study. We used a linear regression meta-modeling approach to calculate the population expected value of partial perfect information and a Gaussian approximation to calculate population expected value of sample information, and we subtracted the cost for research to obtain the expected net benefit of sampling (ENBS). We determined the optimal trial sample sizes that maximized ENBS. RESULTS: Using a willingness-to-pay threshold of $100,000 per quality-adjusted life-year, the PSA found that a no-AP strategy had the highest expected net benefit, with a 60% probability of being cost-effective, and 2-y AP had a 37% probability. The optimal sample size for an RCT to determine AP efficacy and dental-related PJI risk would require approximately 421 patients per arm with an estimated cost of $14.7 million. The optimal sample size for an observational study to inform quality-of-life parameters would require 2,211 patients with an estimated cost of $1.2 million. The 2 trial designs had an ENBS of approximately $25 to $26 million. CONCLUSION: Given the uncertainties associated with AP guidelines for dental patients after TKA, we conclude there is value in conducting further research to inform the risk of PJI, effectiveness of AP, and quality-of-life values. KNOWLEDGE TRANSFER STATEMENT: The results of this value-of-information analysis demonstrate that there is substantial uncertainty around clinical, health status, and economic parameters that may influence the antibiotic prophylaxis guidance for dental patients with total knee arthroplasty. The analysis supports the contention that conducting additional clinical research to reduce decision uncertainty is worth pursuing and will inform the antibiotic prophylaxis debate for clinicians and dental patients with prosthetic joints.

Is Antibiotic Prophylaxis Cost-effective for Dental Patients Following Total Knee Arthroplasty?

INTRODUCTION: Routine antibiotic prophylaxis (AP) to prevent prosthetic joint infection remains controversial. The lack of prophylaxis guideline consensus from the American Academy of Orthopaedic Surgeons (AAOS) and the American Dental Association (ADA) contributes to clinician confusion. OBJECTIVES: This cost-effectiveness decision model informs the AP debate and guideline development by comparing the benefits, harms, and costs of alternative prophylaxis strategies. METHODS: A Markov state-transition model was developed comparing lifetime health outcomes and costs of alternative AP strategies for dental patients aged 65 y with a history of total knee arthroplasty (TKA). Based on our interpretation of AP recommendations from the AAOS and ADA, incremental cost-effectiveness ratios were calculated to compare the following strategies: no AP, AP for the first 2 y after a TKA, and lifetime AP. RESULTS: The no-AP strategy had the lowest average lifetime costs ($17,119) and quality-adjusted life years (11.2151). Compared with a no-prophylaxis strategy, the 2-y AP strategy had incremental costs of $56 and 0.0006 QALYs gained and was cost-effective (incremental cost-effectiveness ratio = $95,100) when a willingness-to-pay threshold of $100,000 per quality-adjusted life year was used. Based on the results of 1-way sensitivity analysis, the no-AP strategy was cost-effective when we modestly increased base case amoxicillin adverse event estimates that were substantially lower than estimates reported in previous models. When plausible combinations of important model parameters were varied, model results suggested that there may be clinical scenarios when AP may be appropriate for some medically at-risk patient populations. CONCLUSION: The results of cost-effectiveness decision modeling generally support questioning routine AP for dental patients with TKA. Sensitivity analyses suggest that prophylaxis may be cost-effective for patient populations with a higher medical risk of infection. This finding is consistent with the recommendations of the 2015 ADA practice guideline and the appropriate use criteria jointly developed by the AAOS and the ADA. KNOWLEDGE TRANSFER STATEMENT: The results of this decision modeling research support the contention that routine AP before invasive dental procedures to prevent prosthetic joint infection may not be cost-effective for patients without medical conditions, potentially conferring a higher infection risk. Model sensitivity analyses suggest that there may be clinical situations when medically at-risk patients benefit from AP.

Surgical approaches in osteomyelitis. Use of laser Doppler flowmetry to determine nonviable bone.

The surgical management of osteomyelitis includes radical debridement on nonviable bone. Laser Doppler flowmetry is a method for directly assessing the functional microcirculation in bone. The early results of the use of this technique as a surgical adjunct in the management of osteomyelitis are promising.

Cortical bone microperfusion: response to ischemia and changes in major arterial blood flow.

In order to investigate the effects of short-term ischemia on cortical bone microperfusion, an isolated porcine tibia diaphyseal preparation based on intact nutrient vessels was developed. Laser Doppler flowmetry (LDF) was utilized to assess continuously the cortical microcirculation and the response to short-term ischemia. The femoral artery was isolated and clamped to develop the condition of bone ischemia. On release of the clamp, reactive hyperemia was documented in all animals. Using a roller pump connected to a segment of femoral artery, the same preparation was utilized to investigate the effect of a changing femoral artery flow on the cortical microcirculation. A positive correlation between LDF output and change in arterial inflow (r = 0.64) was defined. This model has the potential for studying the effect of ischemia on bone cell viability.

Musculoskeletal function assessment: reference values for patient and non-patient samples.

Although researchers and clinicians are encouraged to use health-status questionnaires to evaluate, monitor, and modify care, their use is hindered by the lack of reference values. Without reference values, it is difficult to interpret or evaluate questionnaire scores. In this paper, we present reference values for the Musculoskeletal Function Assessment, a 101-item health-status questionnaire designed and validated for patients with a broad range of musculoskeletal disorders. We describe reference values for two samples: non-patients (n = 123) and patients with isolated extremity injuries (n = 274). For the non-patient sample, descriptive statistics are presented by age and gender, measured at one point in time. For the patient sample, descriptive statistics are provided for seven Orthopaedic Trauma Association/AO diagnostic groups, measured at two points in time. Reference values for changes in the Musculoskeletal Function Assessment total score are described for patients 3 and 9 months and 6 and 12 months after injury. The total scores by post-injury interval, across the diagnostic groups, are significantly better at follow-up than at baseline (p = 0.00). Reference values for changes in total scores are also described in terms of these diagnostic groups across post-injury intervals. Musculoskeletal Function Assessment total scores for Orthopaedic Trauma Association/AO diagnostic groups are significantly better at follow-up than at baseline (p < 0.03). Changes in the total score are also tested for responsiveness with use of standardized response means. Large effects are demonstrated for patients completing the Musculoskeletal Function Assessment at 3 and 9 months (1.03), and small effects are demonstrated for those completing it at 6 and 12 months (0.49). Moderate and large effects are demonstrated for Orthopaedic Trauma Association/AO diagnostic groups across post-injury intervals.

Torsion and bending analysis of internal fixation techniques for femoral neck fractures: the role of implant design and bone density.

To evaluate pin/screw/plate fixation for management of femoral neck fractures, 39 proximal femora were tested in both torsion and flexion under physiological loading conditions. Three, four, or five implants of six commonly used multiple-fixation devices, and a sliding hip screw with and without an additional 6.5-mm cancellous screw were examined in paired femora. The intact and postfixation femora were initially subjected to a single applied moment, and the torsion and bending stiffness were determined from the load-deformation data. Postfixation femora were also subjected to cyclic loading in flexion at three load ranges, and fixation was judged successful if no failure occurred on or before 1,500 cycles of 667 to 2,000 N of a combined compressive force and moment. Anterior-posterior and lateral radiographs of each specimen were taken after fixation in order to evaluate Singh's index of bone density, fracture reduction, implant placement, and cross-sectional diameter of the femoral neck. Bone density was also evaluated by computed tomography (CT) and physical measurement of core samples obtained from the femoral head. The results indicate that there appears to be no justification for the use of more than three pin/screw implants for management of femoral neck fractures. Bone density was found to correlate with fracture stability and may be a useful predictor of fixation success.

Development of a musculoskeletal extremity health status instrument: the Musculoskeletal Function Assessment instrument.

Despite an increasing reliance on the use of health status measures to assess and evaluate medical care, no single instrument is currently available for use with the broad range of patients with musculoskeletal disorders of the extremities that is commonly seen in clinical practice. In this paper, we report on the development of the Musculoskeletal Function Assessment instrument, a 100-item self reported health status instrument that is designed to meet this need. The instrument was developed in two phases. During the first phase, items were selected on the basis of interviews with 135 patients and 12 clinicians and from reviews of existing health status instruments. The items then were grouped into categories. During the second phase, the instrument was tested for reliability and content validity using a sample of 327 patients with one of five musculoskeletal disorders of the upper and lower extremities (fractures, soft-tissue injuries, repetitive motion disorders, osteoarthritis, and rheumatoid arthritis). The patients were selected from both community and academic sites. Content validity also was demonstrated, based on a review of item selection procedures, expert opinion, and the distribution of scores on the instrument.

Musculoskeletal Function Assessment instrument: criterion and construct validity.

The Musculoskeletal Function Assessment (MFA) instrument, a health status instrument with 100 self-reported health items, was designed for use with the broad range of patients with musculoskeletal disorders of the extremities commonly seen in clinical practice. In this paper, we report on its criterion and construct validity. Criterion validity was tested against physicians' ratings of patient functioning (e.g., upper functioning, lower functioning, daily activities, recreational functioning, emotional adjustment, and overall functioning) and standard clinical measures (e.g., grip strength, walking speed, fine motor skills, knee and elbow strength, and range of motion). Significant correlations (p < or = 0.05) between its scores, physicians' ratings, and clinical measures support the MFA's criterion validity. Construct validity was demonstrated against existing measures of health status (e.g., measures of lower and upper mobility, activity level and satisfaction, health status, social support, pain, emotional status, and quality of life), in accordance with clinical hypotheses about the effect of musculoskeletal disorders on functioning (e.g., type and number of problems, severity of illness or injury, and comorbidities) and by an analysis of demographic characteristics (e.g., sex, education, income, health insurance, and employment) against the MFA scores. Discriminant construct validity was supported in an analysis of MFA scores by patient disease groups (p < or = 0.01).

The use of laser Doppler flowmetry to evaluate anterior cruciate blood flow.

The purpose of this study was to quantitate the blood flow of the anterior cruciate ligament in vivo. Functional flow was evaluated using laser Doppler flowmetry (LDF), for which the output signal, blood cell flux (BCF), is expressed in terms of volts. Ten patients undergoing routine arthroscopic surgery with clinically intact anterior cruciate ligaments were selected at random for participation in the study. Under arthroscopic visualization, a 2.2-mm probe was placed through a trocar sleeve into the anterior cruciate ligament after the arthroscopic procedure. Pulsatile flow within the ligament was observed in all patients. The mean maximum BCF value ranged from 101 to 274 mV; SD range was +/- 3-9 mV. The mean minimum BCF ranged from 75 to 197 mV; SD range was +/- 0 to 9 mV. Laser Doppler flowmetry offers significant promise as a method for measurement of in vivo anterior cruciate and cruciate substitution blood flow.

Laser Doppler flowmetry for bone blood flow measurement: correlation with microsphere estimates and evaluation of the effect of intracapsular pressure on femoral head blood flow.

Laser Doppler flowmetry (LDF) was used to measure bone blood flow in the rabbit femoral head and femoral condyles. To correlate the LDF output signal blood cell flux to in vivo blood flow, simultaneous measurements using LDF and 85Sr-labeled microspheres were made in an adult rabbit model. There was no correlation between the two methods for blood flow in the femoral condyles and the correlation between the two methods for blood flow in the femoral head does not achieve statistical significance. An LDF signal of 0.4 V was approximately equal to a microsphere measured flow rate of 0.4 ml blood/g bone/min. The strength of the correlation in the latter case may have been affected by (a) large arteriovenous shunts, (b) inadequate mixing of the microspheres with a left ventricular injection, and (c) insufficient numbers of microspheres present in the bone samples with which to satisfy the mathematical requirements of the microsphere method. When LDF was used to evaluate the effect of elevated intracapsular pressure on femoral head blood flow in skeletally mature rabbits, femoral head subchondral bone blood flow declined with increasing intracapsular pressure from a baseline value of 0.343 +/- 0.036 to a value of 0.127 +/- 0.27 at 120 cm of water pressure. The decline in femoral head blood flow was statistically significant at pressures of 40 cm of water or higher (p less than 0.001), and evaluation of sections of the proximal femora made from preterminal disulphine blue injections confirmed these findings. Intracapsular tamponade has an adverse effect on femoral head blood flow beginning well below central venous pressure and should be considered in the pathophysiology of posttraumatic and nontraumatic necrosis of the femoral head. Laser Doppler flowmetry was easy to use and appears to be a reproducible technique for evaluating femoral head blood flow, offering distinct advantages over the microsphere technique for measuring bone blood flow. Further studies of the in vivo calibration of the LDF method for bone blood flow are necessary for the method to have potential for clinical application.

Laser Doppler flowmetry for bone blood flow measurements: helium-neon laser light attenuation and depth of perfusion assessment.

Laser Doppler flowmetry (LDF) has been successfully used in clinical and experimental settings to evaluate bone perfusion but unanswered questions regarding its capabilities and limitations still remain. This study was undertaken to determine absorption of He-Ne laser light (632.8 nm) and maximum depth for flow assessment (threshold thickness) under optimal conditions in bone. Light transmittance in bovine bone samples of femora and tibia was measured after each step of grinding and depth of penetration calculated. The threshold thickness was obtained by placing the same samples in a flow chamber where a solution of 2% latex circulated beneath; flow was detected by a laser Doppler probe resting on top of the sample. The results showed a significantly higher depth of penetration for trabecular than for cortical bone. A regression analysis showed a high correlation between the inorganic fraction of the bone and the depth of penetration. The maximum depth at which the laser Doppler probe can evaluate flow in bone conditions was found to be 2.9 +/- 0.2 mm in cortical bone, 3.5 +/- 0.3 mm in bone covered by 1 mm cartilage and 3.5 +/- 0.2 mm in trabecular bone. The study showed the limitations of LDF in bone and their correlations to various bone properties.

Comparison of the effect of reamed and unreamed locked intramedullary nailing on blood flow in the callus and strength of union following fracture of the sheep tibia.

This study was performed to compare the effects of reamed and unreamed locked intramedullary nailing on blood flow in the callus and early strength of union in a fractured sheep tibia model. After the creation of a standardized short spiral fracture by three-point bending with torsion, each tibia was stabilized by the insertion of a locked intramedullary nail. Ten animals were allocated randomly into two groups: one that had reaming prior to nail insertion and one that did not. Blood flow was measured in real time with use of laser Doppler flowmetry. Endosteal perfusion was determined at the fracture site before and after nail insertion. Perfusion of the callus was measured at three locations (proximal diaphysis, fracture site, and distal diaphysis) and at three time intervals (2, 6, and 12 week follow-up). All animals were killed 12 weeks postoperatively, and the tibiae were tested to failure in four-point bending. Nailing with reaming resulted in a larger decrease in overall endosteal perfusion than nailing without reaming (p < 0.015). The presence or absence of reaming did not affect blood flow within fracture callus. Perfusion of callus was greatest at 6 weeks of follow-up. Bending strength and stiffness were the same in both groups at 12 weeks. The study demonstrated that perfusion of callus and early strength of union are similar following intramedullary nailing with or without reaming.

Augmentation of femoral neck fracture fixation with an injectable calcium-phosphate bone mineral cement.

The first goal of this study was to determine if augmentation with an injectable, in situ setting, calcium-phosphate cement that is capable of being remodeled and was designed to mimic bone mineral significantly improved the strength and stiffness of fixation in a cadaveric femoral neck fracture model. The second goal was to determine if greater increases in fixation strength were achieved as the bone density of the specimen decreased. Sixteen pairs of fresh cadaveric human femora with a mean age of 70.9 years (SD = 17.2 years) were utilized. The bone density of the femoral neck was measured with dual-energy x-ray absorptiometry. The femoral head was impacted vertically with the femoral shaft fixed in 12 degrees of adduction using a materials testing machine to create a fully displaced fracture. Following fracture, 30% inferior comminution was created in each specimen. One randomly chosen femur from each pair underwent anatomic reduction and fixation with three cannulated cancellous bone screws, 7 mm in diameter, in an inverted triangle configuration. The contralateral femur underwent the same fixation augmented with calcium-phosphate cement. Specimens were preconditioned followed by 1.000 cycles to one body weight (611.6 N) at 0.5 Hz to simulate single-limb stance loading. The stiffness in the first cycle was observed to be significantly greater in cement-augmented specimens compared with unaugmented controls (p < 0.05). After cycling, each specimen was loaded at 10 mm/min until complete displacement of the fracture surface and failure of fixation occurred. Specimens augmented with bone mineral cement failed at a mean of 4,573 N (SD = 1,243 N); this was significantly greater (p < 0.01) than the mean for controls (3,092 N, SD = 1,258 N). The relative improvement in fixation strength (augmented/control x 100%) was not inversely correlated to femoral neck bone density (p = 0.25, R2 = 0.09), was weakly correlated to the volume of cement injected (p = 0.07, R2 = 0.22), and was inversely related to the fixation failure load of the control specimen (p = 0.001, R2 = 0.54). There was a mean relative improvement in fixation strength of 169.6% (SD = 77.5). These findings suggest that calcium-phosphate cement provides initial beneficial augmentation to fixation of femoral neck fractures.

Cortical bone perfusion in plated fractured sheep tibiae.

The limited contact dynamic compression plate and partial contact plate were designed to decrease contact with cortical bone in an attempt to decrease cortical ischemia, remodeling, and eventual porosis under the plate after use of standard dynamic compression plates. This study quantified cortical bone blood flow beneath the plate with these three different designs in a sheep tibia fracture model. In 18 skeletally immature sheep, the right tibia was fractured and then was internally fixed with an interfragmentary screw and a dynamic compression plate, limited contact dynamic compression plate, or partial contact plate. At 12 weeks, cortical bone perfusion was assessed with laser Doppler flowmetry in nine areas beneath the plate. The baseline (before fracture) cortical bone cell flux averaged 100 +/- 60 mV. After fracture, this decreased to 60 +/- 48 mV (p < 0.0003); immediately after plating, the perfusion averaged 29 +/- 25 mV (p < 0.01). Cortical bone perfusion then increased to 106 +/- 52, 165 +/- 71, and 163 +/- 71 mV at 2, 6, and 12 weeks after fracture (p < 0.001 for all when compared with values after plating). No significant differences in cortical perfusion were seen between the types of plate. Cortical porosity under the plate was assessed with digital density analysis of microradiographs of this region. No significant difference was seen between the types of plate in this analysis or in biomechanical and disulphine blue perfusion analysis. Thus, no significant advantage was seen for the new plate designs used in this model. This lack of advantage may be a result of the immature animals used in the study, the protocol for blood flow measurement, the invasive periosteal stripping employed to create the fracture, or all three. However, as advantages with the new plate designs have been seen in other studies, this area warrants further investigation.

Operative treatment of complex acetabular fractures. Combined anterior and posterior exposures during the same procedure.

Over a four-year period, twenty-four patients who had a complex fracture of the acetabulum were treated by the same surgeon. The operation consisted of open reduction and internal fixation with combined anterior and posterior exposures during the same period of anesthesia. The cases of these patients were reviewed to ascertain whether access to both acetabular columns during the same procedure facilitates open reduction and internal fixation and to determine the indications for this combined procedure. As determined by intraoperative assessment and at follow-up examination four to thirty-two months postoperatively, anatomical reduction and rigid fixation were achieved in 88 per cent of the patients. No patient had an infection of the wound. All twenty-four patients had some degree of heterotopic ossification; as defined by Brooker et al., it was Class I in seven, Class II in thirteen, Class III in three, and Class IV in one. However, the heterotopic ossification limited motion of the hip enough to impair function in only two patients. We concluded that combined anterior and posterior exposures facilitate reduction and fixation and that these approaches should be used during the same period of anesthesia whenever anatomical reduction and rigid internal fixation cannot be achieved through a single exposure. Heterotopic ossification should be expected postoperatively, but it is rarely clinically important, at least in the short term.

Ipsilateral fractures of the femoral neck and shaft. A treatment protocol.

Ipsilateral fractures of the femoral neck and shaft present diagnostic difficulties and complex choices as to treatment. A review of the eighty-three cases reported in the literature revealed that one-third of the fractures of the femoral neck were missed initially. No consistent method of treatment can be recommended on the basis of this review. Our present protocol for this double fracture is treatment with immediate internal fixation: the femoral neck fracture is given first priority and is reduced and immobilized with multiple cancellous screws, and the femoral shaft fracture is then treated with retrograde closed intramedullary Küntscher nailing. Appropriate exceptions to the protocol exist. We reviewed the cases of fifteen patients who were treated at Harborview Medical Center and University Hospital from 1971 through 1981. Our experience with the first two patients led to the development of our protocol, which was applied in the thirteen subsequent double fractures. Two of the fifteen femoral-neck fractures were missed initially. All of the fractures had united four months postoperatively. Of the nine patients who were followed for three years or more, two had aseptic necrosis of the femoral head. Compared with other reports, our protocol seems to have produced somewhat better functional results.

Treatment of open fractures of the tibial shaft: Ender nailing versus external fixation. A randomized, prospective comparison.

A randomized, prospective study comparing Ender nailing with external fixation for open fractures of sixty-three tibiae (sixty patients) was undertaken. Ender nailing proved to be at least as effective as external fixation with respect to seven parameters: time to union, tibial alignment, total number of operations, ranges of motion of the knee and ankle, pain, presence of infection, and complications. Ender nailing is a safe alternative to external fixation for grade-I and grade-II open fractures. It should not be used for comminuted fractures, which might shorten about the nails.

Fractures of the femoral neck in patients between the ages of twelve and forty-nine years.

Femoral neck fractures in young adults have a poor prognosis because the incidence of non-union and aseptic necrosis is high. We reviewed the results in twenty-seven consecutive patients with a femoral neck fracture who were younger than fifty years and who were treated with a standard protocol at Harborview Medical Center from 1975 to 1981. There were twenty-two male and five female patients, and they ranged in age from twelve to forty-nine years (mean, 32.4 years). Twenty patients were involved in high-velocity trauma and twelve of them had significant injuries to other organ systems. One of the remaining seven patients had sustained the fracture while running, and in the other six the fracture was associated with a metabolic disorder. Eight patients had a Garden Stage-II fracture; twelve, Stage-III; and seven, Stage-IV. The fractures were fixed with multiple 6.5-millimeter cancellous screws after adequate closed reduction, which was usually performed within eight hours after injury. All of the fractures united and there were no wound infections. Aseptic necrosis of the femoral head developed in five patients (20 per cent), three of whom had symptoms at the time of writing and will require surgical revision of the hip.

Comparison of the Musculoskeletal Function Assessment questionnaire with the Short Form-36, the Western Ontario and McMaster Universities Osteoarthritis Index, and the Sickness Impact Profile health-status measures.

We compared the reliability, validity, and responsiveness of the Musculoskeletal Function Assessment (MFA) questionnaire with those of three commonly used health-status measures: the Short Form-36 (SF-36), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Sickness Impact Profile (SIP). The MFA, like the other health-status measures, demonstrated good reliability (intraclass correlation coefficients of more than 0.70), good sensitivity and specificity (more than 70 per cent), good criterion validity that correlated with physicians' ratings (p < 0.01), and good construct validity that correlated with the characteristics of the patients (p < 0.01). It also demonstrated better content validity than the other questionnaires, with no ceiling or floor effects for the total score. In addition, it was more responsive than the SF-36; for eight of the eleven comparisons, it was more efficient (relative efficiency of more than 2.00) in measuring changes in function between the baseline values and the values determined at the latest follow-up evaluation. These findings suggest that the MFA can be used to assess the health status of patients who have a musculoskeletal disorder.

Short musculoskeletal function assessment questionnaire: validity, reliability, and responsiveness.

BACKGROUND: A short questionnaire on functional status was designed for use in community-based outcome studies and in the management of individual patients who have musculoskeletal disease. As most musculoskeletal care is delivered in community practices, short, validated instruments are necessary to perform clinical studies on the effectiveness of treatment in this setting. METHODS: A forty-six-item questionnaire was created as an extension of the work to develop the longer, 101-item Musculoskeletal Function Assessment (MFA) questionnaire. The Short Musculoskeletal Function Assessment (SMFA) questionnaire consists of the dysfunction index, which has thirty-four items for the assessment of patient function, and the bother index, which has twelve items for the assessment of how much patients are bothered by functional problems. The SMFA questionnaire was evaluated for reliability, validity, and responsiveness in a population of 420 patients who had a musculoskeletal disease or injury. RESULTS: The SMFA questionnaire demonstrated excellent internal consistency and stability, with most values greater than 0.90. Content validity for the dysfunction and bother indexes was supported with very little skew (less than 1.00), few ceiling effects (less than 5 percent), and no floor effects. Convergent validity was supported with significant correlations between the SMFA dysfunction and bother indexes and the physicians' ratings of patient function (for example, activities of daily living, recreational and leisure activities, and emotional function [rho > or = 0.40]) and standard clinical measures (for example, grip strength and walking speed [r > or = 0.401). Convergent and discriminant construct validity of the SMFA indexes were demonstrated (p < 0.01) in comparisons with clinical, demographic, Short Form-36 (SF-36), and life-change data. The responsiveness of the SMFA questionnaire to change over time was demonstrated with standardized response means ranging from moderate (0.76) to large (-1.14) for patients who had changes in health status. CONCLUSIONS: The SMFA questionnaire may be used for clinical assessments of the impact of treatment in groups of patients who have musculoskeletal disease or injury. It also may be used in clinical settings to provide reliable and valid assessments of the health status of an individual patient.