Pronation on weightbearing radiographs does not correlate with pronation from weightbearing CT scans.

INTRODUCTION: In hallux valgus (HV), first metatarsal pronation is increasingly recognized as an important aspect of the deformity. The purpose of this study was to compare pronation in HV patients determined from the shape of the lateral head of the first metatarsal on AP weightbearing radiographs with pronation calculated from weightbearing CT (WBCT) scans. METHODS: Patients were included in this study if they had preoperative and 5-month postoperative WBCT scans and corresponding weightbearing AP radiographs of the affected foot. Pronation of the first metatarsal on WBCT scans was measured using a 3D CAD model and the alpha angle and categorized into four groups on radiographs. Association between pronation groups on radiographs and WBCT scans was determined using Spearman correlation coefficients (rs) and by comparing mean WBCT pronation of the first metatarsal between plain radiograph pronation groups. RESULTS: Agreement between the two observers' pronation on radiographs was good (k = 0.634) and moderate (k = 0.501), respectively. There was no correlation between radiographic pronation and the 3D CAD model (rs < 0.15). Preoperatively, there was weak correlation between the alpha angle and the radiographic pronation groups (rs = 0.371, P = 0.048) although this relationship did not hold postoperatively (rs = 0.330, P = 0.081). There was no difference in mean pronation calculated on WBCT scans between the plain radiographic groups. CONCLUSION: Pronation of the first metatarsal measured on weightbearing AP radiographs had moderate interobserver agreement and was only weakly associated with pronation measured from WBCT scans. These results suggest that first metatarsal pronation measured on weightbearing radiographs is not a substitute for pronation measured on WBCT scans. LEVEL OF EVIDENCE: III, retrospective cohort study.

A Comparison of Imaging Outcomes From 2 Weightbearing CT Modalities.

BACKGROUND: The use of weightbearing images to diagnose foot and ankle injuries continues to offer hope for improved insight into pathologies, but weightbearing CT imaging has been limited by availability. The ability to apply force to the lower limb in a horizontal bore CT system may offer an adaptation to currently available imaging systems that provides access to weightbearing images without the acquisition of additional expensive imaging space or equipment. METHODS: In order to determine whether a horizontal CT system could produce the same results as a standing CT, 3 images of one foot from 10 subjects was obtained and standard measures were calculated. Each subject underwent a standing CT scan, a scan in a horizontal bore CT machine while the subject pressed against a pedal with spring resistance and a finally a scan with the foot placed on the pedal but without any pressure. RESULTS: No statistically significant difference between the standing and pedal-based CTs resulted. Navicular height and Meary angle (axial) were statistically different from nonweightbearing for both standing and horizontal systems. The horizontal results were statistically different from nonweightbearing in IM angle, talocalcaneal angle, and talonavicular coverage. No differences from nonweightbearing were found for either system in talar tilt, talocrural angle, or the lateral Meary angle. CONCLUSION: The results in this initial study of normal control subjects suggest that a pedal-based loading mechanism may adapt a horizontal-bore CT system for the acquisition of weightbearing images. CLINICAL RELEVANCE: The ability to acquire a weightbearing CT from a horizontal bore CT machine can make these images more available.

Association of First Metatarsal Pronation Correction With Patient-Reported Outcomes and Recurrence Rates in Hallux Valgus.

BACKGROUND: The purpose of this study was to determine if a postoperative decrease in first metatarsal pronation on 3-dimensional imaging was associated with changes in patient-reported outcomes as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS) physical function, pain interference, and pain intensity domains or recurrence rates in patients with hallux valgus (HV) who undergo a first tarsometatarsal fusion (modified Lapidus procedure). METHODS: Thirty-nine consecutive HV patients who met the inclusion criteria and underwent a modified Lapidus procedure had preoperative and ≥2-year postoperative PROMIS scores and had first metatarsal pronation measured on preoperative and at least 5-month postoperative weightbearing CT scans were included. Multivariable regression analyses were used to investigate differences in the change in PROMIS domains preoperatively and 2 years postoperatively between patients with "no change/increased first metatarsal pronation" and "decreased first metatarsal pronation." A log-binomial regression analysis was performed to identify if a decrease in first metatarsal pronation was associated with recurrence of the HV deformity. RESULTS: The decreased first metatarsal pronation group had a significantly greater improvement in the PROMIS physical function scale by 7.2 points (P = .007) compared with the no change/increased first metatarsal pronation group. Recurrence rates were significantly lower in the decreased first metatarsal pronation group when compared to the no change/increased first metatarsal pronation group (risk ratio 0.25, P = .025). CONCLUSION: Detailed review of this limited cohort of patients who underwent a modified Lapidus procedure suggests that the rotational component of the HV deformity may play an important role in outcomes and recurrence rates following the modified Lapidus procedure. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

The Association of Crista Volume With Sesamoid Position as Measured From 3D Reconstructions of Weightbearing CT Scans.

BACKGROUND: Malposition of the sesamoids relative to the first metatarsal head may relate to intersesamoid crista underdevelopment or erosion. Using 3-dimensional models created from weightbearing CT (WBCT) scans, the current work examined crista volume and its relationship to first metatarsal pronation and sesamoid station. METHODS: Thirty-eight hallux valgus (HV) patients and 10 normal subjects underwent weightbearing or simulated WBCT imaging. The crista was outlined by the inferior articular surface, and a line was drawn to connect the lowest point of each sulcus on either side of the intersesamoidal crista throughout the length of the crista. The volume was calculated. Sesamoid station and first metatarsal pronation were calculated from the 3D reconstructions. The mean crista volumes between HV and normal patients were statistically compared, as were the crista volume and pronation angle between sesamoid stations. RESULTS: The mean crista volume in HV patients was 80.10 ± 35 mm3 and in normal subjects was 150.64 ± 24 mm3, which differed significantly between the 2 groups (P < .001). Mean crista volumes were found to be statistically significantly different between the sesamoid stations (P < .001) with decreasing crista volumes significantly and strongly correlated with increasing sesamoid station (r = -0.80, P < .001). There was no difference in the mean pronation angle between the 4 sesamoid stations (P = .37). The pronation angle was not associated with crista volume (P = .52). CONCLUSION: HV patients have lower mean crista volume than normal patients. Crista volume is correlated with sesamoid station. Pronation of the first metatarsal was not associated with crista volume. CLINICAL RELEVANCE: Crista volume may offer an additional determinant for the severity of hallux valgus.

Clinical and magnetic resonance imaging outcomes following platelet rich plasma injection for chronic midsubstance Achilles tendinopathy.

BACKGROUND: The successful treatment of chronic mid-substance Achilles tendinopathy remains elusive. Approximately 25% to 50% of patients fail conservative treatment modalities. Scientific evidence has supported the use of platelet rich plasma (PRP) in the tendon healing process, however despite initial promise there is a paucity of clinical data to validate a role for PRP in the treatment of tendon disorders including chronic midsubstance Achilles tendinopathy. METHODS: As an alternative to operative treatment, our practice offers patients with chronic midsubstance Achilles tendinopathy intratendinous injection of PRP. We retrospectively reviewed all patients treated for Achilles tendinopathy with PRP injection over a 2-year period. Baseline and post injection functional scores including the Foot and Ankle Ability Measure (FAAM), Foot and Ankle Ability Measure - Sports (FAAMS), and the Short Form health survey (SF-8) were examined. Patients also underwent post-injection magnetic resonance imaging (MRI), which were compared to available pre-injection MRI data. RESULTS: Ten patients were identified for this study. Pre- and postinjection functional outcome scores were available for eight of ten patients. The average SF-8 score improved from 24.9 to 30.0, the average FAAM score improved from 55.4 to 65.8, and the average FAAMS score improved from 14.8 to 17.4. Complete MRI data was available for six patients. Only one in six Achilles tendons demonstrated qualitative MRI improvement post-injection. CONCLUSION: Patients who received PRP injection demonstrated modest improvement in functional outcome measures, however MRI appearance of diseased Achilles tendons remained largely unchanged following PRP injection.

Correlation of Different Methods of Measuring Pronation of the First Metatarsal on Weightbearing CT Scans.

BACKGROUND: There is no consensus in the foot and ankle literature regarding how to measure pronation of the first metatarsal in patients with hallux valgus. The primary purpose of this study was to compare 2 previously published methods for measuring pronation of the first metatarsal and a novel 3-dimensional measurement of pronation to determine if different measurements of pronation are associated with each other. METHODS: Thirty patients who underwent a modified Lapidus procedure for their hallux valgus deformity were included in this study. Pronation of the first metatarsal was measured on weightbearing computed tomography (WBCT) scans using the α angle with reference to the floor, a 3-dimensional computer-aided design (3D CAD) calculation with reference to the second metatarsal, and a novel method, called the triplanar angle of pronation (TAP), that included references to both the floor (floor TAP) and base of the second metatarsal (second TAP). Pearson's correlation coefficients were used to determine if the 3 calculated angles of pronation correlated to each other. RESULTS: Preoperative and postoperative α angle and 3D CAD had no correlation with each other (r = 0.094, P = .626 and r = 0.076, P = .694, respectively). Preoperative and postoperative second TAP and 3D CAD also had no correlation (r = 0.095, P = .624 and r = 0.320, P = .09, respectively). However, preoperative and postoperative floor TAP and α angle were found to have moderate correlations (r = 0.595, P = .001 and r = 0.501, P = .005, respectively). CONCLUSION: The calculation of first metatarsal pronation is affected by the reference and technique used, and further work is needed to establish a consistent measurement for the foot and ankle community. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Effect of the Modified Lapidus Procedure on Pronation of the First Ray in Hallux Valgus.

BACKGROUND: Hallux valgus (HV) is a triplanar deformity of the first ray including pronation of the first metatarsal with subluxation of the sesamoids. The purpose of this study was to investigate if a first tarsometatarsal fusion (modified Lapidus technique), without preoperative knowledge of pronation measured on weightbearing computed tomographic (CT) scans, changed pronation of the first metatarsal and determine if reduction of the sesamoids was correlated with changes in first metatarsal pronation. METHODS: Thirty-one feet in 31 patients with HV who underwent a modified Lapidus procedure had preoperative and at least 5-month postoperative weightbearing CT scans and radiographs. Differences in preoperative and postoperative pronation of the first metatarsal using a 3-dimensional computer-aided design, HV angle, and intermetatarsal angle (IMA) were calculated using Wilcoxon signed-rank tests. After dividing patients into groups based on sesamoid station, Kruskal-Wallis H tests were used to compare first metatarsal pronation between the groups. RESULTS: The mean preoperative and postoperative pronation of the first metatarsal was 29.0 degrees (range 15.8-51.1, SD 8.7) and 20.2 degrees (range 10.4-32.6, SD 5.4), respectively, which was a mean change in pronation of the first ray of -8.8 degrees (P < .001). There was no difference in pronation of the first ray when stratified by postoperative sesamoid position (P > .250). The average preoperative and postoperative IMA was 16.7 degrees (SD 3.2) and 8.8 degrees (SD 2.8), which demonstrated a significant change (P < .001). CONCLUSIONS: The modified Lapidus procedure was an effective tool to change pronation of the first ray. Reduction of the sesamoids was not associated with postoperative first metatarsal pronation. LEVEL OF EVIDENCE: Level IV, case series.

Proprioception after total ankle arthroplasty.

BACKGROUND: Total ankle arthroplasty (TAA) is becoming an effective treatment for end-stage ankle arthritis. It is unknown if TAA alters the patient's ability to sense ankle joint position. MATERIALS AND METHODS: Thirteen unilateral TAA patients with a minimum of 2-years followup completed proprioceptive testing of the TAA and the contralateral side. The task was to reproduce a given ankle angle using a joystick-driven device while the lower limb was obscured from view. Nine angles were tested, including two angles in dorsiflexion, three in plantarflexion, two in inversion, and two in eversion. A repeated-measures ANOVA was used to evaluate the results. RESULTS: No statistically significant differences between the TAA ankle and the contralateral side were found. CONCLUSION: TAA does not cause a change in proprioceptive abilities in arthritis patients when compared to the contralateral, unaffected side in a small sample of unilateral patients. Surgeons and rehabilitation professionals may use this information when designing rehabilitation plans following the insertion of a TAA.

Pilot Study of a 3-Dimensional Method for Analysis of Pronation of the First Metatarsal of Hallux Valgus Patients.

BACKGROUND:: The current work sought to quantify pronation of the first metatarsal relative to the second metatarsal and of the proximal phalanx of the great toe relative to the first metatarsal. METHODS:: Three-dimensional models were reconstructed from weightbearing computed tomography (CT) images (10 hallux valgus, 10 normal). The orientations of bones related to hallux valgus (HV) (ie, the phalanx, first and second metatarsals) were determined from coordinate systems established by selecting landmarks. After determining the hallux valgus and intermetatarsal angles, additional calculations geometrically determined the 3-dimensional (3D) angles using the aeronautical system of yaw-pitch-roll. The 3D geometrically determined angles were compared to the conventional plain radiographic angles. RESULTS:: HV measurements taken with CT and 3D computer-aided design (3DCAD) geometric methods were the same as measurements taken from plain radiographs (P > .05). The average pronation of the first metatarsal relative to the second metatarsal was 8.2 degrees greater in the hallux valgus group (27.3 degrees) than in the normal group (19.1 degrees) (P = .044). A regression analysis of pronation vs intermetatarsal angle (IMA) was not found to be significant. There was also no correlation between pronation of the great toe and first metatarsal in the HV group. CONCLUSIONS:: The pronation angle of the first metatarsal relative to the second metatarsal between normal and hallux valgus patients was larger in HV patients but was not well correlated with the IMA. CLINICAL RELEVANCE:: The findings of this study indicate that pronation may need to be considered in the operative correction of hallux valgus for restoration of normal anatomy.

Posttraumatic ankle arthritis: an update on conservative and surgical management.

This manuscript offers current information regarding the examination, conservative treatment, and surgical treatment for individuals with posttraumatic arthritis. Although inflammatory and osteoarthritis can occur, posttraumatic arthritis is the most common form of arthritis to affect the ankle. Posttraumatic ankle arthritis occurs in a generally younger, active population. It is radiographically characterized by an asymmetrical degenerative process and may be associated with a history of trauma, instability, and/or lower extremity malalignment. When choosing between conservative/nonoperative versus surgical intervention, the extent of subchondral bone exposed and the time over which the arthritis has developed are factors that should be considered. The role and effectiveness for conservative treatment, such as medication, patient education, shoe modification, bracing, stretching, mobilization, strengthening, and symptom management, needs to be further determined. Surgical procedures for posttraumatic ankle arthritis can include distraction arthroplasty, arthrodesis, or total ankle arthroplasty. Unlike the relatively new procedure of distraction arthroplasty, the outcomes for arthrodesis have been well defined. Arthrodesis generally has a good outcome, but its limitations have been recognized. These limitations include the extended time required to achieve fusion, potential for nonunion, arthritis developing in adjacent joints, leg length discrepancy, malalignment, chronic edema, symptoms due to the hardware, stress fractures, and continued pain. While first generation total ankle arthroplasty led to poor results, advancements in prosthetic design and surgical technique have revived optimism regarding total ankle arthroplasty as an alternative to arthrodesis. The key for the future of total ankle arthroplasty may not be related to the development of newer ankle components but rather in refining the criteria to determine who would best benefit from joint replacement versus fusion.

Evidence of validity for the Foot and Ankle Ability Measure (FAAM).

BACKGROUND: There is no universally accepted instrument that can be used to evaluate changes in self-reported physical function for individuals with leg, ankle, and foot musculoskeletal disorders. The objective of this study was to develop an instrument to meet this need: the Foot and Ankle Ability Measure (FAAM). Additionally, this study was designed to provide validity evidence for interpretation of FAAM scores. METHODS: Final item reduction was completed using item response theory with 1027 subjects. Validity evidence was provided by 164 subjects that were expected to change and 79 subjects that were expected to remain stable. These subjects were given the FAAM and SF-36 to complete on two occasions 4 weeks apart. RESULTS: The final version of the FAAM consists of the 21-item activities of daily living (ADL) and 8-item Sports subscales, which together produced information across the spectrum ability. Validity evidence was provided for test content, internal structure, score stability, and responsiveness. Test retest reliability was 0.89 and 0.87 for the ADL and Sports subscales, respectively. The minimal detectable change based on a 95% confidence interval was +/-5.7 and +/--12.3 points for the ADL and Sports subscales, respectively. Two-way repeated measures ANOVA and ROC analysis found both the ADL and Sports subscales were responsive to changes in status (p < 0.05). The minimal clinically important differences were 8 and 9 points for the ADL and Sports subscales, respectively. Guyatt responsive index and ROC analysis found the ADL subscale was more responsive than general measures of physical function while the Sports subscale was not. The ADL and Sport subscales demonstrated strong relationships with the SF-36 physical function subscale (r = 0.84, 0.78) and physical component summary score (r = 0.78, 0.80) and weak relationships with the SF-36 mental function subscale (r = 0.18, 0.11) and mental component summary score (r = 0.05, -0.02). CONCLUSIONS: The FAAM is a reliable, responsive, and valid measure of physical function for individuals with a broad range of musculoskeletal disorders of the lower leg, foot, and ankle.

An outcome study of chronic Achilles tendinosis after excision of the Achilles tendon and flexor hallucis longus tendon transfer.

BACKGROUND: A number of operative techniques, including decompression with debridement and flexor hallucis longus (FHL) tendon augmentation, have been described for chronic degenerative Achilles tendinosis. Decompression with debridement has been shown to be effective; however, pain and functional limitation can persist in individuals with more severe tendon involvement. Augmentation with the FHL tendon can add mechanical support; however, difficulty in achieving proper tendon tensioning and the potential to leave behind painful diseased tendon are disadvantages of the technique. The purpose of this study was to present the results of a modified technique in which the Achilles tendon is completely excised and the FHL tendon is transferred. METHODS: Fifty-six surgeries using this modified technique were done between October, 1994, and March, 2002, for patients with chronic degenerative Achilles tendinosis. Forty-four patients with and average age of 58.2 (SD 10.1) years and an average time of followup of 3.4 (SD 1.9) years were available for testing. All subjects were mailed a packet of standardized questionnaire information that included the Self-Reported Health Related Quality of Life measures Short Form (SF-36) and the subjective component of the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle and Hindfoot Score. Nineteen patients returned to the clinic for objective assessment. Statistical analysis tested for a difference in the SF-36 scores between our subjects and the general United States population and for a difference in strength and range of motion between the involved and uninvolved lower extremities. RESULTS: Pain decreased in 95.5% (n = 42) patients, and 86.4% (n = 38) patients were satisfied with the result. There was no significant difference (p > .05) between the SF-36 scores obtained by our sample compared to the general United States population. The average AOFAS score for the 19 patients was 91.6 (SD 7.7). Dorsiflexion range of motion was not significantly different (p = 0.17); however, significant deficits were found in plantarflexion range of motion (p = 0.001) and plantarflexion strength (p < 0.025). Strength deficits were 30% on average; however, all but one patient could do a heel raise. CONCLUSION: Complete Achilles tendon excision reduces pain while preserving functional status. Although strength deficits persisted, these deficits did not seem to affect the functional status in this sample of patients.

Joint replacement in the hallux metatarsophalangeal joint.

Joint replacement of the hallux metatarsophalangeal joint has not enjoyed the same success as hip and knee arthroplasties. Silastic implants have achieved a high patient satisfactory rate but have caused many complications, including silicone synovitis and lymph node inflammation. Metal and polyethylene hemiarthroplasties and total toe replacements seem to be more promising although results are preliminary. Problems with these implants seem to be related to soft tissue instability of the joint; patients who have hallux rigidus have more success than patients who have hallux valgus or rheumatoid arthritis. Severe complications can be treated with removal and synovectomy or arthrodesis, depending on the length and alignment of the foot, as well as the functional demands of the patients. It would be beneficial to have more data on these implants so that improvements can be made in design and patient selection.

Subtalar coalitions in the adult.

Tarsal coalitions, while relatively uncommon, are typically identified in adult patients during an evaluation for ankle instability, sinus tarsus pain, and/or pes planovalgus. The true incidence of tarsal coalition is unknown with estimates ranging from 1% to 12% of the overall population. The most common area of involvement of the subtalar joint is the middle facet, and heightened awareness should be present in adult patients with limited motion of the subtalar joint. Standard radiographic imaging, to include a Harris heel view, is recommended initially, although computerized tomography scan and MRI are often necessary to confirm the diagnosis.

Foot and ankle fractures in elderly white women. Incidence and risk factors.

BACKGROUND: Although foot and ankle fractures are among the most common nonspinal fractures occurring in older women, little is known about their epidemiology. This study was designed to determine the incidence of and risk factors for foot and ankle fractures in a cohort of 9704 elderly, nonblack women enrolled in the multicenter Study of Osteoporotic Fractures. METHODS: At their first clinic visit, between 1986 and 1988, the women provided information regarding lifestyle, subjective health, and function. Bone mineral density was measured in the proximal and distal parts of the radius and in the calcaneus. The women were followed for a mean of 10.2 years, during which time 301 of them had a foot fracture and 291 had an ankle fracture. The fractures were classified with use of a modification of the Orthopaedic Trauma Association's guidelines. RESULTS: The incidence of foot fractures was 3.1 per 1000 woman-years, and the incidence of ankle fractures was 3.0 per 1000 woman-years. The most common ankle fracture was an isolated fibular fracture (prevalence, 57.6%), and the most common foot fracture was a fracture of the fifth metatarsal (56.9%). Women who sustained an ankle fracture had been slightly younger at the time of study enrollment than the women who did not sustain such a fracture (71.0 compared with 71.7 years), they had a higher body mass index (27.6 compared with 26.5), and they were more likely to have fallen within the twelve months prior to filling out the original questionnaire (38.1% compared with 29.7%). The appendicular bone mineral density was not significantly different between these two groups of subjects. Women who sustained a foot fracture had a lower bone mineral density in the distal part of the radius (0.345 g/cm (2) compared with 0.363 g/cm (2) ) and a lower calcaneal bone mineral density (0.394 g/cm (2) compared with 0.404 g/cm (2) ) than the women without a foot fracture, they were less likely to be physically active (62.3% compared with 67.8%), and they were more likely to have had a previous fracture after the age of fifty (45.5% compared with 36.8%) and to be using either long or short-acting benzodiazepines. CONCLUSIONS: Overall, foot fractures appeared to be typical osteoporotic fractures, whereas ankle fractures occurred in younger women with a relatively high body mass index.

Revision ankle arthrodesis.

Between 1996 and 1999, we performed successful revision ankle arthrodesis for aseptic nonunion in 10 patients using external fixation with bone graft and an implantable bone stimulator. The etiology of the ankle arthrosis in the patients was post-traumatic in eight and rheumatologic in two. The average age of the patients was 54. On average, each patient had received 2.5 previous surgeries (range, 1 to 5) prior to the original fusion attempt. Fusion occurred in all 10 of these patients at an average of 12.8 weeks following revision (range, nine to 20 weeks). Complications occurred in two patients: one had a pin tract infection which resolved with local pin care and oral antibiotics; the second patient had a varus malalignment which was accommodated with orthotics. This patient also had a deep peroneal nerve neuropraxia which resolved with observation. We evaluated all 10 patients with clinical and radiographic examination, and determined their functional results for a duration of follow-up of 15 months (range, six to 36 months). Using a modification of the AOFAS ankle/hindfoot scoring system, the results were: three excellent, four good, two fair, and one poor. All but one of these patients were satisfied with the outcome of this procedure. Radiographic analysis supported good clinical alignment and solid fusion.

Osteolysis of structural autograft after calcaneocuboid distraction arthrodesis for stage II posterior tibial tendon dysfunction.

Surgical treatment of stage II posterior tibial tendon dysfunction that fails nonoperative treatment is amenable to operative treatment. This commonly consists of a medial soft-tissue reconstruction and lateral column lengthening. We report on 32 patients undergoing distraction calcaneocuboid arthrodesis using an autogenous tricortical iliac crest graft. Almost 50% of patients did not go on to complete and uneventful incorporation of the graft at the arthrodesis site. Two different types of failure were noted. The first was classic nonunion which maintained structural integrity of the graft. The second was osteolysis and collapse of the graft accompanying the nonunion. Risk factors included smoking, K-wire fixation and possibly larger deformities requiring Achilles tendon lengthening. Complications of nonunion were salvageable with reoperation.

Epidemiology of foot and ankle injuries in the workplace.

Injuries to the ankle, foot, and toes of injured workers are common. Although the workers' compensation system attempts to collect information about these injuries and report them in a meaningful way, the process is somewhat inconsistent, inaccurate, and provides information relevant to government agencies but not to physician organizations seeking to improve the prevention and treatment of work-related injuries. Several improvements in data collection could greatly increase the system's efficiency and usefulness. The first is to establish a national system of uniform data collection from each State. The second improvement involves standardization of the forms and means that the data are collected from the worker including a system to retrieve information that has been omitted during the initial encounter. The third, and most important, refinement is to change the reporting of the illness to match currently accepted medical diagnosis codes (ICD-9). Using the current system and making these improvements, the United States would be able to collect more meaningful data on work injuries in this country. From that point forward medical interventions could then be created and their effects more meaningfully analyzed. All those involved in the care and treatment of the injured worker must recognize not only the limitations of the collected data but also how this information can be manipulated. For example, whereas the total cost of benefits paid by employers increased during one decade the average cost per covered employee decreased. Employers and insurers can argue that their total costs have consistently risen but only by knowing that the cost per covered employee had decreased during that same time period can that argument be countered. Similarly, implementation of certain safety practices during a given time period may be accompanied by a reduction in the number of injuries. Changes in the laws that altered injury reporting and reduced the coverage for certain injuries, however, may have created a situation where the reported injury rates were reduced by accounting practice, not medical practice. It is also well established that insurance company profits may be linked as much to the general economy and stock market as they are to premiums and claims. It is hoped that this article begins an understanding of the extent of the problem of foot and ankle injuries in the working population. Additional statistical information on specific topics is presented elsewhere in this issue.

Complications of total ankle replacement.

Total ankle arthroplasty with second-generation prostheses is gaining popularity. Complications do and will occur with this group of replacements, just as they do with all other arthroplasties, whether at the knee, hip, elbow, shoulder, or wrist. Even if the complications are understood and the preventative measures or solutions are well thought out, there is occasionally no clear-cut answer to the problem. Although there are many obstacles to a successful outcome, most of the complications reported here are preventable with good patient selection and technique or at least treatable once they occur.

Characterization of a mixed MRSA/MRSE biofilm in an explanted total ankle arthroplasty.

Bacterial biofilms have been observed in many prosthesis-related infections, and this mode of growth renders the infection both difficult to treat and especially difficult to detect and diagnose using standard culture methods. We (1) tested a novel coupled PCR-mass spectrometric (PCR-MS) assay (the Ibis T5000) on an ankle arthroplasty that was culture negative on preoperative aspiration and then (2) confirmed that the Ibis assay had in fact detected a viable multispecies biofilm by further micrographic and molecular examinations, including confocal microscopy using Live/Dead stain, bacterial FISH, and reverse-transcriptase-PCR (RT-PCR) assay for bacterial mRNA. The Ibis technology detected Staphylococcus aureus, Staphylococcus epidermidis, and the methicillin resistance gene mecA in soft tissues associated with the explanted hardware. Viable S. aureus were confirmed using RT-PCR, and viable cocci in the biofilm configuration were detected microscopically on both tissue and hardware. Species-specific bacterial FISH confirmed a polymicrobial biofilm containing S. aureus. A novel culture method recovered S. aureus and S. epidermidis (both methicillin resistant) from the tibial metal component. These observations suggest that molecular methods, particularly the new Ibis methodology, may be a useful adjunct to routine cultures in the detection of biofilm bacteria in prosthetic joint infection.