Biomechanical analysis of stresses to the fifth metatarsal bone during sports maneuvers: implications for fifth metatarsal fractures.

Fifth metatarsal stress fractures are an increasing problem in elite and recreational athletic populations. One possible mechanism of injury is the many bending moments applied to the fifth metatarsal during dynamic sports maneuvers involving rapid changes in direction and speed. A potentially important bending moment is loading of the base versus the head of the fifth metatarsal, which tends to cause a bending moment along the bone. To determine which maneuver applies the greatest pressure differential between the base and head of the fifth metatarsal, 10 college-aged male athletes performed running straight, jump take-off, jump landing, cutting right, cutting left, and accelerating while plantar pressures were recorded using a Pedar insole system (Novel Electronics, Inc., St. Paul, MN). Peak pressure at the fifth metatarsal base was subtracted from the peak pressure at the fifth metatarsal head to obtain the fifth metatarsal pressure differential-a corollary to the bending moment. The greatest fifth metatarsal pressure differential was observed during acceleration maneuvers (20 + or - 13.1 N/cm(2); P < 0.0001) followed by running straight (11.6 + or - 8 N/cm(2); P < 0.0008). The other maneuvers had low pressure differentials: jump take-off (4.2 + or - 10.6 N/cm(2)), jump landing (3.7 + or - 9.2 N/cm(2)), cutting left (2.3 + or - 4.2 N/cm(2)), and cutting right (-2.1 + or - 10 N/cm(2)). It appears that acceleration maneuvers may apply the largest bending moments to the fifth metatarsal and could lead to stress fractures. Because fifth metatarsal stress fractures are associated with rapid increases in training volume, reducing the number of acceleration events may be effective in altering the balance between bone resorption and bone formation and reducing stress fracture risk. Careful planning of training programs allowing for adequate rest between intense bouts of exercise involving many acceleration maneuvers may be the best preventative measure.

Prosthesis use in persons with lower- and upper-limb amputation.

This study identified clinical (e.g., etiology) and demographic factors related to prosthesis use in persons with upper- and lower-limb amputation (ULA and LLA, respectively) and the effect of phantom limb pain (PLP) and residual limb pain (RLP) on prosthesis use. A total of 752 respondents with LLA and 107 respondents with ULA completed surveys. Factors related to greater use (hours per day) for persons with LLA included younger age, full- or part-time employment, marriage, a distal amputation, an amputation of traumatic etiology, and an absence of PLP. Less use was associated with reports that prosthesis use worsened RLP, and greater prosthesis use was associated with reports that prosthesis use did not affect PLP. Having a proximal amputation and reporting lower average PLP were related to greater use in hours per day for persons with an ULA, while having a distal amputation and being married were associated with greater use in days per month. Finally, participants with LLA were significantly more likely to wear a prosthesis than those with ULA. These results underscore the importance of examining factors related to prosthesis use and the differential effect that these variables may have when the etiology and location of amputation are considered.

Regional foot pressure during running, cutting, jumping, and landing.

BACKGROUND: Evaluating shoes during sport-related movements may provide a better assessment of plantar loads associated with repetitive injury and provide more specific data for comparing shoe cushioning characteristics. HYPOTHESIS: Accelerating, cutting, and jumping pressures will be higher than in straight running, differentiating regional shoe cushioning performance in sport-specific movements. STUDY DESIGN: Controlled laboratory study. MATERIALS AND METHODS: Peak pressures on seven anatomic regions of the foot were assessed in 10 male college athletes during running straight ahead, accelerating, cutting left, cutting right, jump take-off, and jump landing wearing Speed TD and Air Pro Turf Low shoes (Nike, Beaverton, Ore). Pedar insoles (Novel, Munich, Germany) were sampled at 99 Hz during the 6 movements. RESULTS: Cutting and jumping movements demonstrated more than double the pressure at the heel compared with running straight, regardless of shoe type. The Air Pro Turf showed overall lower pressure for all movement types (P<.0377). Cutting to the left, the Air Pro Turf shoe had lower heel pressures (36.6 +/- 12.5 N/cm(2)) than the Speed TD (50.3 +/- 11.2 N/cm(2)) (P<.0001), and the Air Pro Turf had lower great toe pressures than the Speed TD (44.8 +/- 8.1 N/cm(2) vs 54.4 +/- 8.4 N/cm(2); P= .0002). The Air Pro Turf also had significantly lower pressures than the Speed TD at the central forefoot during acceleration (38.2 +/- 8.3 N/cm(2) vs 50.8 +/- 7.4 N/cm(2); P<.0001). CONCLUSION: Sport-related movements load the plantar surface of the foot more than running straight. Shoe cushioning characteristics were more robustly assessed during sport-related movements (4 significant results detected) compared with running straight (1 significant result detected). CLINICAL RELEVANCE: There is an interaction between shoe cushioning characteristics and sport-related movements that may influence plantar pressure and repetitive stress injuries.

Foot and ankle injuries in dance.

Although dancers develop overuse injuries common in other athletes, they are also susceptible to unique injuries. This article reviews common foot and ankle problems seen in dancers and provides some basic diagnosis and treatment strategies.

Perioperative medication management for the patient with rheumatoid arthritis.

The treatment of rheumatoid arthritis has improved dramatically in recent years with the advent of the latest generation of disease-modifying antirheumatic drugs. Despite these advances, in some patients inflammation is not diminished sufficiently to prevent irreversible musculoskeletal damage, thus requiring surgical intervention to reduce pain and improve function. In these cases, the orthopaedic surgeon frequently encounters patients on a drug regimen consisting of nonsteroidal anti-inflammatory drugs, glucocorticoids, methotrexate, and biologic agents (disease-modifying antirheumatic drugs). Consultation with a rheumatologist is recommended, but the surgeon also should be aware of these medications that could potentially affect surgical outcome. Prudent perioperative management of these drugs is required to optimize surgical outcome. A balance must be struck between minimizing potential surgical complications and maintaining disease control to facilitate postoperative rehabilitation of patients with rheumatoid arthritis.

Reliability of the Foot Function Index:: A report of the AOFAS Outcomes Committee..

BACKGROUND: There currently is no widely used, validated, self-administered instrument for measuring musculoskeletal functional status in individuals with nonsystemic foot disorders. The purpose of this paper was to report on the assessment of reliability of one of these instruments. We wanted to determine if the Foot Function Index (FFI), which has been validated in rheumatoid patients without fixed foot deformity or prior foot surgery, would be reliable for a population of patients with foot complaints without systemic disease. METHODS: Patients were recruited from five orthopaedic offices where the physicians were members of the American Orthopaedic Foot and Ankle Society. Patients were asked to complete the FFI at the time of their initial office visit and then were given a second copy to complete and return by mail 1 week after their visit. RESULTS: Ninety-six patients completed the first questionnaire, and 54 patients completed the second. Reliability in this population was acceptable with an average of 23.5% of the patients providing retest values within one point of the initial response and an average of 45.3% of the patients providing the same response, for a total of 68.8% of all respondents answering within one point between their initial and second questionnaire. In two of the three categories, there were frequent nonresponses or no applicable responses. Four questions, two in the pain section and two in the activity limitation section, generated 20% or more of the nonapplicable answers. CONCLUSIONS: The FFI appears to be a reasonable tool for low functioning individuals with foot disorders. It may not be appropriate for individuals who function at or above the level of independent activities of daily living.

Issues of importance to patients seeking care from members of the AOFAS: a preliminary report of the outcomes committee of the AOFAS.

BACKGROUND: The purpose of this multi-center study was to examine the outcomes of importance for patients seeking treatment for foot and ankle disorders. An improved understanding of patient outcome preferences will assist surgeons in improving patient satisfaction. METHODS: An open-ended priority function questionnaire was administered to 235 patients presenting as new patients to five different outpatient locations. The questionnaire was designed to identify activities of importance to patients and was based on the McMaster Toronto Arthritis (MACTAR) patient preference disability questionnaire. Subjects were asked to list the specific activities that were limited by their condition. Open-ended answers were written on five blank spaces and then ranked as to their importance. The visual analog pain scale was recorded as a measure of the severity of the patient's symptoms at the time the response was made. The outpatient settings were two university hospitals, two private offices with academic affiliation, and one private office. Two hundred thirty-five surveys were collected between September and November of 2000; 227 surveys were acceptable for analysis. The respondents included 132 females (58.1%), 94 males (41.4%) and one patient who did not specify his gender (0.4%). The mean age was 45.8 (range 18 to 83) years. RESULTS: Average pain at the time of assessment was 2.7 on a scale of 0 to 9 and was reported to increase to 4.8 in a typical day. The most frequently ranked limitations were difficulty with walking (159), running (73), standing (55), and exercise (54). Walking also was the issue ranked as the highest priority (77 of 159), while running (11 of 73), standing (10 of 55) and exercise (3 of 54) were assigned lesser priority values. Only 68 of 227 respondents failed to list walking as an issue. Work, sleep, and social activities were not commonly cited as issues of importance. CONCLUSION: Patients presenting to office practices identified as specializing in foot and ankle disorders are predominantly middle-aged women in mild to moderate pain. Walking is the function most frequently identified as a problem and ranked as the highest priority for improvement. Social limitations were unlikely to be named as a limitation in this population.

Impact of educational intervention on confidence and competence in the performance of a simple surgical task.

BACKGROUND: Many complex new procedures involve a learning curve, and patients treated by individuals who are new to a procedure may have more complications than those treated by a practitioner who has performed the intervention more frequently. Still, at some point on the learning curve, each individual must decide that he or she is qualified to perform a procedure, presumably on the basis of his or her level of confidence, background, education, and skill. To evaluate the interrelationship of these factors, we designed a study in which we assessed the performance of a simulated knee joint injection. METHODS: Ninety-three practitioners attending a continuing medical education session on knee injection were randomized to receive skills instruction through the use of a printed manual, a video, or hands-on instruction; each performed one injection before and after instruction. The participants completed pre-instruction and post-instruction questionnaires gauging confidence and also provided self-assessments of their performances of injections before and after instruction. Self-assessments were compared with objective performance standards measured by custom-designed knee models with electronic sensors that detected correct needle placement. RESULTS: Before instruction, the participants' confidence was significantly but inversely related to competent performance (r = -0.253, p = 0.02); that is, greater confidence correlated with poorer performance. Both men and physician-practitioners displayed higher pre-instruction confidence (p < 0.01), which was not correlated with better performance. After instruction, performance improved significantly in all three training groups (p < 0.001), with no significant differences in efficacy detected among the three groups (p = 0.99). After instruction, confidence correlated with objective competence in all groups (r = 0.24, p = 0.04); however, this correlation was weaker than the correlation between the participants' confidence and their self-assessment of performance (r = 0.72, p = 0.001). CONCLUSIONS: Even low-intensity forms of instruction improve individuals' confidence, competence, and self-assessment of their skill in performing the fairly straightforward psychomotor task of simulated knee injection. However, men and physicians disproportionately overestimated their skills both before and after training, a finding that worsened as confidence increased. The inverse relationship between confidence and competence that we observed before the educational intervention as well as the demographic differences that we noted should raise questions about how complex new procedures should be introduced and when self-trained practitioners should begin to perform them.

Alternative to the modified jones procedure: outcomes of the flexor hallucis longus (FHL) tendon transfer procedure for correction of clawed hallux.

BACKGROUND: The modified Jones procedure is the traditional operative procedure for correction of a clawed hallux, although the deformity may be caused by overpull of one of three different muscles. In this study we present the radiographic and functional outcomes of flexor hallucis longus (FHL) tendon transfer as treatment for clawed hallux. The transfer is performed by drawing two thirds of the FHL tendon up through a drill hole in the proximal phalanx and then suturing it medially back to the remaining third. METHODS: We retrospectively identified 19 patients (22 feet) who had FHL tendon transfer for correction of clawed hallux over a period of 5 years. Followup was an average of 51.0 (range 6 to 74; +/- 3.8) months after the procedure. Outcome and patient satisfaction were determined using the Long-Form Musculoskeletal Function Assessment (MFA) score. Patients were asked whether they were satisfied, somewhat satisfied, or dissatisfied with the overall outcome and were asked about shoewear limitations. Preoperative and postoperative radiographs were evaluated in 15 patients (17 feet). We measured the hallux valgus and interphalangeal (IP) angles on the anteroposterior (AP) radiographs. On the lateral view we measured the angle of the IP joint, the metatarsophalangeal (MTP) joint, and the talometatarsal angle. Statistical analysis was done using a repeated measures ANOVA (p < 0.05). RESULTS: On the lateral radiographs, the hallux IP joint angle (p < 0.0012; n = 15) and hallux MTP joint angle (p < 0.0265; n = 15) were significantly reduced postoperatively. On AP radiographs, the hallux valgus angle (p < 0.0334) was significantly reduced; however, the IP angle and the talometatarsal angle were not significantly different after surgery. Patients had an average MFA score of 14.6 (+/-3.8 standard error, range 1 to 35; n = 19). Thirteen patients were fully satisfied and six were somewhat satisfied with the overall result of the surgery. Four patients thought that their hallux limited the types of shoes they could wear, while 15 did not. CONCLUSION: It has been shown that clawed hallux can result from excessive motor function in one of three muscles: FHL tendon, peroneus longus (PL), and extensor hallucis longus (EHL). This study suggests that transfer of part of the tendon of the FHL is an effective alternative operative procedure for correction of clawed hallux.

The efficacy of two methods of ankle immobilization in reducing gastrocnemius, soleus, and peroneal muscle activity during stance phase of gait.

BACKGROUND: Immobilization to limit muscle activity is a common therapeutic and posttreatment event. There are potential time and resource savings if a prefabricated boot can replace a custom applied cast. The purpose of this study was to determine if muscle activity reduction is similar using a fiberglass cast versus a prefabricated (Aircast FoamWalker) boot. METHODS: Surface EMG data were recorded from the gastrocnemius, soleus, and peroneals of 12 normal adults while walking barefoot, in a fiberglass cast with a cast shoe (cast), and while wearing an Aircast FoamWalker (boot). Subjects walked at their self-selected speed for 10 trials in each condition, and the order of barefoot, cast, and boot was randomly assigned. The data were rectified, integrated across stance phase and normalized to a percent of each subject's barefoot mean integrated EMG (iEMG) value. For each muscle, a linear mixed-effects statistical model (subject by trial by condition) was utilized to determine if iEMG activity levels were reduced by immobilization compared to barefoot walking. RESULTS: Activity for all muscles was significantly lower in the boot compared with barefoot (p <.05). The cast iEMG levels were significantly different from barefoot for the soleus and peroneals (p <.05). Gastrocnemius activity was significantly decreased in the boot when compared with the cast (p <.0001). The greater reduction in iEMG levels for the boot indicates that it is superior to a fiberglass cast in reducing gastrocnemius muscle activity during the stance phase of gait. CONCLUSIONS: The data show that a prefabricated boot is as effective as a custom applied cast in reducing soleus and peroneal muscle iEMG during stance phase. The boot was more effective in reducing gastrocnemius activity when compared to the cast. CLINICAL RELEVANCE: This study suggests that a prefabricated boot may be used in place of a custom cast when the goal of treatment is to limit muscle activity of the leg.

The effect of walking speed on center of mass displacement.

The movement of the center of mass (COM) during human walking has been hypothesized to follow a sinusoidal pattern in the vertical and mediolateral directions. The vertical COM displacement has been shown to increase with velocity, but little is known about the mediolateral movement of the COM. In our evaluation of the mediolateral COM displacement at several walking speeds, 10 normal subjects walked at their self-selected speed and then at 0.7, 1.0, 1.2, and 1.6 m/s in random order. We calculated COM location from a 15-segment, full-body kinematic model using segmental analysis. Mediolateral COM displacement was 6.99 +/- 1.34 cm at the slowest walking speed and decreased to 3.85 +/- 1.41 cm at the fastest speed (p < 0.05). Vertical COM excursion increased from 2.74 +/- 0.52 at the slowest speed to 4.83 +/- 0.92 at the fastest speed (p < 0.05). The data suggest that the relationship between the vertical and mediolateral COM excursions changes substantially with walking speed. Clinicians who use observational gait analysis to assess walking problems should be aware that even normal individuals show significant mediolateral COM displacement at slow speeds. Excessive vertical COM displacement that is obvious at moderate walking speeds may be masked at slow walking speeds.

Ordering and interpreting rheumatologic laboratory tests.

Many mechanical and systemic conditions can cause joint pain and synovitis. When rheumatologic illness is suspected, the initial evaluation begins with an accurate history, physical examination, and selective use of confirmatory testing, which can help avoid common pitfalls inherent in serologic evaluation. Tests for erythrocyte sedimentation rate, C-reactive protein level, rheumatoid factor, antinuclear antibodies, anticardiolipin antibodies and lupus anticoagulant, HLA-B27, uric acid level, and Lyme disease, either alone or in combination, may support certain diagnoses. Using these tests nonselectively may yield false-positive results, causing unnecessary concern and expense. However, using these tests effectively may reduce the number of unneeded invasive procedures.