Charcot arthropathy of the foot and ankle in patients with idiopathic neuropathy

BACKGROUND

Charcot neuroarthropathy in the developed countries is primarily associated with diabetic neuropathy. This study investigated a series of patients with Charcot arthropathy associated with idiopathic peripheral neuropathy to evaluate the natural history in these patients and to evaluate the efficacy of a treatment protocol used for diabetic Charcot joints.

METHODS

The records and radiographs of patients with Charcot arthropathy of the foot and ankle treated between 1986 and 2009 were retrospectively reviewed. Patients with known causes of or risk factors for peripheral neuropathy were excluded, identifying 82 feet in 59 patients with idiopathic neuropathy. Twenty-three (39%) were bilateral. The average age was 76 years and the average follow-up was 60 months. Data were analyzed for medical history and diagnoses, medications, anatomic classification of Charcot arthropathy, history of ulcerations, ambulatory status, shoe wear and bracing, and operative interventions. Patient care was based on previous published treatment algorithms, based on conservative management with operative intervention reserved for nonhealing ulcers, infection, and/or nonplantigrade, unbraceable feet. Therapeutic success was a plantigrade foot with healed soft tissue envelope that allowed weight-bearing.

RESULTS

In all, 55% involved the midfoot (type 1), 34% the hindfoot (type 2), and 11% the ankle, (type 3A). Seventy-one of 82 feet were successfully treated at the time of last follow-up. Thirty-six feet (43%) were treated nonoperatively with success in 33 (92%). Forty-six of 82 feet required operative intervention, with success at last follow-up in 38 (83%). There were 8 operative failures resulting in 2 transtibial amputations and 6 feet with persistent ulceration.

CONCLUSIONS

This series of patients with Charcot arthropathy associated with idiopathic neuropathy demonstrated a wider spectrum of Charcot arthropathy of the foot and ankle than has been previously recognized or documented. At the present time, heightened awareness is needed to promote accurate diagnosis and appropriate treatment in nondiabetic patients with Charcot arthropathy.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Psychometric Comparison of the PROMIS Physical Function CAT With the FAAM and FFI for Measuring Patient-Reported Outcomes

BACKGROUND

Selecting optimal patient-reported outcome (PRO) instruments is critical to improving the quality of health care. The purpose of this study was to compare the reliability, responsiveness, and efficiency of three PRO measures: the Foot and Ankle Ability Measure-Activity of Daily Living subscale (FAAM_ADL), the Foot Function Index 5-point verbal rating scale (FFI-5pt), and the PROMIS Physical Function computerized adaptive test (PF CAT).

METHODS

Data were aggregated from 10 clinical sites in the AOFAS's National Orthopaedic Foot and Ankle Research (OFAR) Network from 311 patients who underwent elective surgery for a disorder of the foot or ankle. Patients were administered the FAAM_ADL, FFI-5pt, and PF CAT at their preoperative visit and at 6 months after surgery. Reliabilities were evaluated using a Rasch model. Responsiveness was calculated using paired samples t test and efficiency was recorded as number of seconds to complete the instrument.

RESULTS

Similar reliabilities were found for the three instruments. Item reliabilities for FAAM_ADL, FFI-5pt, and PF CAT were all .99. Pearson reliabilities for FAAM_ADL, FFI-5pt, and PF CAT were .95, .93, and .96, respectively. On average, patients completed the FAAM_ADL in 179 seconds, the FFI-5pt in 194 seconds, and the PF CAT in 44 seconds, ( P < .001). The PF CAT and FAAM_ADL showed significant improvement ( P = .01 and P = .001, respectively) in patients' physical function after treatment; the FFI-5pt did not show improvement.

CONCLUSIONS

Overall, the PF CAT performed best in terms of reliability, responsiveness, and efficiency in this broad sample of foot and ankle patients. It can be a potential replacement for the conventional PRO measures, but further validation is needed in conjunction with the PROMIS Pain instruments.

LEVEL OF EVIDENCE

Level I, prospective comparative outcome study.

Peroneus longus tears associated with pathology of the os peroneum

BACKGROUND

There is a range of different types of tears and pathology of the peroneal tendons. One of the least common types is the tear of the peroneus longus associated with fracture, enlargement, or entrapment at the cuboid tunnel of the os peroneum. The purpose of this study was to evaluate the pathologic patterns of these uncommon peroneal tendon tears, to review the treatment, and to report the patient outcomes following treatment with excision of the os peroneum, debridement, and tenodesis of the peroneus longus to the peroneus brevis.

METHODS

A 5-year retrospective review of all patients with peroneal tendon tears identified 12 patients operatively treated for peroneus longus tendon tears with associated pathology of the os peroneum, and in whom there was a viable peroneus brevis. All patients were treated with an operative procedure consisting of excision of the os peroneum, debridement, and tenodesis of the peroneus longus to the peroneus brevis. Mean age was 51.5 (range, 33 to 73) years, including 7 males and 5 females. Operative and radiographic records were reviewed to characterize the nature of the peroneus longus tears and associated pathology. Preoperative and postoperative AOFAS hindfoot, SF-36 questionnaires, and Visual Analog Scale (VAS) pain scores were compiled and patient records were reviewed for complications. Mean follow-up after surgery was 63.3 (range, 12 to 114) months.

RESULTS

All of the patients had an os peroneum associated with a complex, irreparable tear of the peroneus longus tendon. The peroneus longus was typically enlarged, fibrotic, and adhered to the surrounding tissues. In 8 patients, the peroneus longus tendon tear was associated with a fracture of the os peroneum, and in 4 patients with an enlarged and entrapped os peroneum which prevented movement at the cuboid tunnel. Of the 12 patients, 9 had partial tears of the peroneus brevis, which were treated with debridement and suture repair. AOFAS hindfoot scores increased from a preoperative mean of 61 (range, 46 to 75) to a postoperative mean of 91.7 (range, 60 to 100). Mean preoperative SF-36 Physical Component Scores (PCS) increased from 36 to 52 postoperatively. Mean VAS pain scores decreased from a preoperative mean of 6.3 (range, 4 to 8) to a postoperative mean of 1.0 (range, 0 to 4). Complications included 2 patients with sural neuritis and 3 with superficial delayed wound healing successfully treated nonoperatively.

CONCLUSION

Tears of the distal peroneus longus tendon, which are much less commonly reported than tears of the peroneus brevis, can be associated with pathology of the os peroneum. Excision of the os peroneum, tendon debridement, and tenodesis of the longus to brevis was an effective surgical technique.

LEVEL OF EVIDENCE

Level IV, case series.

Surgical correction of severe deformity of the ankle and hindfoot by arthrodesis using a compressing retrograde intramedullary nail

BACKGROUND

Tibiotalocalcaneal arthrodesis with a retrograde intramedullary nail is a widely used surgical technique for the treatment of concomitant tibiotalar and subtalar arthritis and correction of accompanying deformity. This study was undertaken to evaluate the union rate, deformity correction, and clinical outcomes achieved using a compressing retrograde intramedullary nail.

METHODS

Thirty tibiotalocalcaneal arthrodeses with an osseous compressing arthrodesis nail system were studied with a mean follow-up of 26 months. Radiographic data were collected on deformity correction and union rate, and clinical outcomes were evaluated using the Visual Analogue Scale (VAS) for pain, the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle/Hindfoot Score, and the Short Form-36 (SF-36) health survey. Records were reviewed for complications and concomitant procedures.

RESULTS

Thirteen of 30 operated limbs had a preoperative coronal plane deformity exceeding 15 degrees. Mean magnitude of correction was 13.2 degrees (range, 0-32 degrees, standard deviation ±9.6). In total, 76% of limbs (23/30) had postoperative coronal deformity of less than 5 degrees. Union was achieved in 96.6% of patients. There were 3 cases of tibial stress reaction, 3 cases of transient plantar nerve irritation, and 3 cases of wound infection. Clinical outcomes demonstrated a reduction in mean VAS score from 6.5 to 1.3 (P < .01), an increase in mean AOFAS Ankle/Hindfoot Scores from 29.7 to 74.3 (P < .01), and an increase in mean total SF-36 scores from 85.6 to 98.8 (P < .01).

CONCLUSION

A compressing retrograde intramedullary nail was effective in achieving deformity correction, a high union rate, and improvement in clinical outcomes.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Gait analysis in orthopedic foot and ankle surgery--topical review, part 1: principles and uses of gait analysis

Gait analysis, the systematic study of human walking, is a field that has been studied for well over 100 years. With the technological and scientific advancements of the last several decades, there has been substantial improvement in our understanding of the mechanics of human walking. Particularly important has been the advancement in understanding of the differences between normal and pathological gait. The purpose of this paper is to review the principles of gait analysis, with a particular focus on the underlying methods and science. This will assist orthopedic foot and ankle surgeons in better understanding the methods and meaning of gait research and the publications that commonly appear in the orthopedic foot and ankle surgery literature.

LEVEL OF EVIDENCE

Level V, expert opinion.

Radiographic and clinical outcomes of joint-preserving procedures for hallux valgus in rheumatoid arthritis

BACKGROUND

The standard treatment for hallux valgus in rheumatoid arthritis has been arthrodesis of the first metatarsophalangeal (MTP) joint. There is limited literature regarding the results of hallux valgus procedures which preserve the first MTP joint in rheumatoid patients. We investigated the radiographic and clinical outcomes of joint-preserving surgery for hallux valgus in a series of rheumatoid patients to evaluate the result of nonarthrodesis reconstruction.

METHODS

Thirty-seven feet with hallux valgus in 27 patients with RA treated with a joint-preserving procedure of the first MTP joint were analyzed radiographically and clinically. Average follow-up was 42 (range, 12-111) months. Twenty feet had Ludloff osteotomies, 15 had scarf osteotomies, and 2 had chevron osteotomies. Radiographs were evaluated preoperatively and postoperatively for hallux valgus angle, 1-2 intermetatarsal angle, and degenerative narrowing of the first MTP joint based the Sharp score and the Larsen grade. Narrowing of the first interphalangeal (IP) joint was based on a modification of the classification of Hattrup and Johnson. Operative complications and required secondary surgeries were tabulated. Clinical outcomes were measured using preoperative and postoperative Short Form-36 (SF-36), AOFAS forefoot scale, and Visual Analogue Scale (VAS) pain questionnaires.

RESULTS

The average hallux valgus angle improved from 37 degrees preoperatively to 15 degrees postoperatively. The average 1-2 intermetatarsal angle improved from 14 degrees preoperatively to 5 degrees postoperatively. The average Sharp score of the first MTP joint was 0.9 preoperatively and 1.6 postoperatively. The average Larsen grade of the first MTP joint was 0.6 preoperatively and 1.4 postoperatively. Range of motion of the first MTP joint was essentially unchanged between preoperative and postoperative measurements. Seven of 37 feet had progression of first IP joint space narrowing, but none were symptomatic. The AOFAS score improved from 45.2 preoperatively to 82.6 at final follow-up (P value < .01). The VAS decreased from 4.8 preoperatively to 1.5 at final follow-up (P value < .02). The SF-36 physical component score decreased from 40.3 preoperatively to 37.4 at final follow-up, and the mental component score remained unchanged, and neither was statistically significant. There were 7 feet (19%) that required a return to surgery: 3 wound infections, 2 arthrodeses for progression of deformity, and 1 each for revision for recurrence and hardware removal.

CONCLUSION

Rheumatoid arthritis patients who undergo a bunionectomy rather than arthrodesis to preserve the first MTP joint have satisfactory clinical and radiographic outcomes. This procedure appeared to be a reasonable alternative to first MTP arthrodesis in patients with relatively preserved joints.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Prospective study of the effect on gait of a two-component total ankle replacement

BACKGROUND

The purpose of this study was to evaluate the functional outcome as measured by prospective gait analysis of patients undergoing total ankle arthroplasty using a 2-component Salto Talaris total ankle prostheses with a fixed polyethylene bearing.

METHODS

Twenty-one patients with severe ankle arthritis who underwent unilateral total ankle arthroplasty using a 2-component Salto Talaris device with a fixed polyethylene bearing were studied prospectively. Mean age was 69 years in 16 female and 5 male patients, and mean follow-up was 37.2 (range, 24-50) months. Three-dimensional gait analysis was performed using a 12-camera digital-motion capture system preoperatively and repeated at a minimum of 2 years postoperatively. Temporospatial measurements included velocity, cadence, step length, and support times. Measured kinematic parameters included sagittal plane range of motion of the ankle, knee, and hip. Kinetic parameters included sagittal plane ankle power and ankle plantarflexion moment.

RESULTS

There was significant improvement in temporospatial parameters, including step length (P = .014) and walking velocity, which increased from 0.9 to 1 m/s (P = .01). Kinematic results showed sagittal plane range of motion of the ankle increased significantly from a mean of 15.8 degrees preoperatively to 20.6 degrees (P = .00005) postoperatively with the increase occurring primarily in dorsiflexion. Kinetic results showed ankle peak power increased from a mean of 0.7 Nm/kg to 1.1 Nm/kg (P = .004).

CONCLUSIONS

A prospective study of gait in patients undergoing total ankle arthroplasty using a 2-component Salto Talaris device with a fixed polyethylene bearing showed, at midterm follow-up, significant improvements in multiple parameters of gait when compared to the patients' own preoperative function.

LEVEL OF EVIDENCE

Level IV, prospective case series.

Hindfoot motion following STAR total ankle arthroplasty: a multisegment foot model gait study

BACKGROUND

One of the rationales for total ankle arthroplasty (TAA) is that it may retard the changes of hypermobility and accelerated arthritis in the hindfoot after ankle arthrodesis. Until recently, it has not been possible to quantify or even objectively demonstrate biomechanical findings to substantiate the theory that postsurgical biomechanical changes in the ankle produce changes in the kinematics of the hindfoot. Standard gait analysis has treated the foot as a single biomechanical unit. This study was undertaken to describe the hindfoot motion following Scandinavian Total Ankle Replacement (STAR) TAA by using multisegment foot model gait analysis.

METHODS

Forty-six patients with a mean age of 66 years underwent a 3D gait analysis following TAR. Mean interval between surgery and gait analysis was 4.9 years (range 2 to 9). The contralateral limb was used as control for each patient. Temporospatial variables and kinematic parameters were studied.

RESULTS

Temporospatial results showed statistically significant differences. Stance time on the affected side was 61.1% ± 2.2% of the gait cycle compared to 63.2% ± 2.1% for the unaffected side. Step length was 55.6 cm ± 10 on the affected side compared to 53.9 cm ± 10 for the unaffected side. Kinematics results were statistically significant: Ankle range of motion (ROM) on the arthroplasty side was 16.8 ± 4.5 degrees compared to 23.6 ± 5.0 on the unaffected side. Sagittal plane ROM was 12.7 ± 4.2 degrees on the arthroplasty side and 17.3 ± 3.5 degrees on the unaffected side. Coronal plane ROM was 4.7 ± 2.4 degrees on the arthroplasty side and 7.5 ± 2.4 degrees on the unaffected side. Transverse plane ROM on the arthroplasty side was 4.1 ± 1.5 degrees and 4.9 ± 1.6 on the unaffected side.

CONCLUSION

This study showed that, in addition to previously documented diminution in sagittal plane motion and gait velocity, some of the residual abnormalities of gait following TAR were comprised of differences in hindfoot function. These results relate to the growing recognition of the importance of understanding hindfoot mechanics apart from those of the tibiotalar joint.

LEVEL OF EVIDENCE

Level III, comparative case series.

Charcot arthropathy of the foot and ankle associated with rheumatoid arthritis

BACKGROUND

Diabetic peripheral neuropathy is now well recognized as the most common cause of Charcot arthropathy of the foot and ankle, but it may be associated with other peripheral neuropathies. While not well known, it is well documented that rheumatoid arthritis is correlated with peripheral neuropathy. However, despite rheumatoid neuropathy, Charcot arthropathy has never been associated with rheumatoid arthritis. We report a series of Charcot arthropathy patients with concomitant rheumatoid arthritis.

METHODS

The medical records of patients treated between 1986 and 2009 with Charcot arthropathy and rheumatoid arthritis were reviewed. Recorded data included neuropathy risk factors, medications, history of ulcerations, ambulatory status, shoe wear, and treatment course. Radiographs of Charcot joints were categorized according to the Brodsky anatomic classification. Patient care was based on published treatment algorithms, emphasizing accommodative, nonoperative treatment with selective surgical interventions. Surgery was indicated for recalcitrant, nonhealing lesions of the soft tissue and/or unbraceable, nonplantigrade feet. A successful outcome was considered an ambulatory patient without amputation and a closed skin envelope at last follow-up.

RESULTS

Four men and 16 women met the diagnostic criteria, resulting in 33 feet in the series. Average age was 61 years, and average follow-up was 4.3 years. In addition to rheumatoid arthritis, 4 patients (7 feet) had hypothyroidism, 4 patients (6 feet) had diabetes, 1 patient (2 feet) had megaloblastic anemia and diabetes, and 1 patient (1 foot) had hypothyroidism and diabetes; however, 17 feet (52%) had no known sources for neuropathy. Charcot involvement was type 1-midfoot in 21 feet (64%), type 2-hindfoot in 7 (21%), type 3a-ankle in 4 (12%), and type 3b-calcaneus in 1 (3%). Twenty-three feet (70%) were treated with conservative modalities. Ten feet (30%) required 15 surgeries, of which an exostectomy was the most common procedure. Of the 33 feet, 3 had persistent ulcerations and 1 underwent major amputation, representing 4 failures.

CONCLUSIONS

Raising awareness within the orthopaedic community, we report a Charcot arthropathy population with a concomitant rheumatoid arthritis diagnosis, emphasizing a relationship between the 2 diseases. Through a conservative treatment regimen combined with selective surgical interventions, satisfactory outcomes were achieved in 88% of the rheumatoid Charcot feet. While several patients had additional neuropathy sources which could cause Charcot arthropathy (eg, diabetes), the majority of feet had no etiologies accounting for neuropathy or neuroarthropathy except rheumatoid arthritis. Further study is required to expand on this relationship between the 2 diseases.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Comparison of gait after total ankle arthroplasty and ankle arthrodesis

BACKGROUND

Prior studies reported improved gait after total ankle arthroplasty and better parameters of gait than those reported in earlier studies of patients after ankle arthrodesis. However, there are very limited data prospectively evaluating the effects on gait after ankle arthroplasty compared with ankle arthrodesis. Controversy remains regarding the relative advantages and disadvantages of these 2 treatments and especially the differences in function between them.

METHODS

We performed a prospective study involving 28 patients with posttraumatic and primary ankle osteoarthritis and a control group of 14 normal volunteers. We compared gait in 14 patients who had undergone ankle arthrodesis with the gait of 14 patients who had ankle arthroplasty preoperatively and at 1 year postoperatively. Three-dimensional gait analysis was performed with a 12-camera digital-motion capture system. Temporospatial measurements included stride length and cadence. The kinematic parameters that were measured included the sagittal plane range of motion of the ankle and the coronal plane range of motion of the ankle. Double force plates were used to collect kinetic parameters such as ankle coronal and plantar flexion-dorsiflexion moments and sagittal plane ankle power. Center of pressure (CoP) and its progression in gait cycle were calculated.

RESULTS

Baseline parameters showed comparability among the treatment and control groups. Temporospatial analysis, using time as the main effect, showed that compared with ankle arthrodesis, patients with total ankle arthroplasty had higher walking velocity attributable to both increases in stride length and cadence as well as more normalized first and second rockers of the gait cycle. Kinematic analysis, using time and intervention as the main effects, showed that patients who had ankle arthroplasty had better sagittal dorsiflexion (P = .001), whereas those undergoing ankle arthrodesis had better coronal plane eversion (P = .01). Neither ankle arthrodesis nor arthroplasty altered the CoP progression during stance phase. Total ankle arthroplasty produced a more symmetrical vertical ground reaction force curve, which was closer to that of the controls than was the curve of the ankle arthrodesis group.

CONCLUSIONS

Patients in both the arthrodesis and arthroplasty groups had significant improvements in various parameters of gait when compared with their own preoperative function. Neither group functioned as well as the normal control subjects. Neither group was superior in every parameter of gait at 1 year postoperatively. However, the data suggest that the major parameters of gait after ankle arthrodesis in deformed ankle arthritis are comparable to gait function after total ankle arthroplasty in nondeformed ankle arthritis.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Prospective study of the treatment of adult primary hallux valgus with scarf osteotomy and soft tissue realignment

BACKGROUND

The scarf osteotomy has been a widely practiced bunion operation, but relatively limited prospective data on its outcomes have been reported. The purpose of this investigation was to prospectively evaluate the clinical and radiographic results of treatment of adult primary hallux valgus using the scarf osteotomy of the first metatarsal with soft tissue realignment.

METHODS

Hallux valgus corrections were performed on 51 patients (53 feet), who were followed for at least 1 year with an average follow-up of 24 months. Mean age at the time of surgery was 59 years, and subjects included 3 male and 48 female patients. Prospective clinical data collected included the American Orthopaedic Foot & Ankle Society (AOFAS) hallux-interphalangeal scale score, the SF-36 scores, and the visual analogue scale (VAS) for pain. Data were collected preoperatively and postoperatively. Prospective radiologic data were also collected including hallux valgus angle (HVA), first-second intermetatarsal angle (IMA), and medial sesamoid position (MSP). Clinical data were collected on complications and reoperations.

RESULTS

Mean AOFAS hallux-interphalangeal score increased from 52 preoperatively to 88 postoperatively. Mean preoperative and last follow-up SF-36 physical component summary increased from 46 preoperatively to 52 postoperatively, whereas mean VAS pain scores decreased from 5.8 preoperatively to 1.1 postoperatively. All the changes in clinical outcomes were statistically significant, except the Mental Component Summary of the SF-36. Mean preoperative HVA decreased from 29 degrees preoperatively to 10.7 degrees in the initial postoperative period and was maintained at last follow-up at 10.6 degrees. The mean preoperative IMA decreased from 13.6 degrees preoperatively to 5.6 degrees in the initial postoperative period and regressed mildly at last follow-up to 7.8 degrees. The mean preoperative MSP grade of 2.3 decreased to 0.5 in the initial postoperative period and regressed mildly to 0.9 at last follow-up. All radiographic changes were statistically significant. The overall complication rate was 15% (8/53), attributable to 4 feet with symptomatic hardware, 2 feet with hallux varus, and 2 feet with progression of first MTP arthritis. Reoperations were performed in 4 feet (8%) for removal of symptomatic hardware.

CONCLUSION

Scarf osteotomy was a reliable technique for correction of moderate to severe hallux valgus and had low rates of complication or recurrence.

LEVEL OF EVIDENCE

Level IV, case series.

Single-stage flexor tendon transfer for the treatment of severe concomitant peroneus longus and brevis tendon tears

BACKGROUND

Although peroneal tendon injuries are a common cause of lateral ankle pain, there is a paucity of literature specifically addressing the treatment of severe concomitant peroneus longus and brevis tears. The purpose of this study was to evaluate patient outcomes following a single-stage flexor tendon transfer for the treatment of severe concomitant tears of both peroneal tendons.

METHODS

Eight patients were treated with a single-stage flexor tendon transfer for severe concomitant peroneus longus and brevis tears over a 15-year period. Mean age at the time of surgery was 54 years (range, 41-67 years), including 4 male and 4 female patients. Tendon transfer of either the flexor hallucis longus (FHL) or flexor digitorum longus (FDL) was performed when both peroneal tendons were found intraoperatively to have severe nonreconstructable tears. Mean follow-up time from surgery was 58 months (range, 12-91 months). Preoperative and postoperative AOFAS hindfoot and visual analog pain scores were prospectively collected, and patient charts were reviewed for complications. A postoperative outcome questionnaire was administered during latest follow-up to assess return to activities, satisfaction, and self-rated patient outcome.

RESULTS

Mean pre- and postoperative AOFAS hindfoot scores increased from 64 (range, 54-77) to 86 (range, 69-100), whereas mean score for pain on a visual analog scale decreased from 4.2 (range, 0.5-6) to 0.7 (range, 0-3). One surgical complication occurred following FDL transfer in a patient who developed a transient peroneal nerve palsy, and 1 patient underwent a subsequent calcaneal osteotomy. Seven of 8 patients reported a return to preoperative activity levels, and no patient required bracing for activities of daily living. All patients reported satisfaction with surgical results, and 7 rated their outcomes as good or excellent.

CONCLUSION

Single-stage flexor tendon transfer is an effective surgical option for the treatment of severe concomitant peroneus longus and brevis tendon tears.

LEVEL OF EVIDENCE

Level IV, case series.

Effect of heating on the mechanical properties of insole materials

BACKGROUND

The most common method of customizing shoe insoles to the shape and surface of the foot is to heat and then mold the materials. The effect of heating on the mechanical properties of these materials is unknown.

METHODS

The properties of individual and common combinations of insole materials were tested before and after heating. Individual materials tested were soft Plastazote (SP), medium Plastazote (MP), Puff (F), and Nickelplast (N); combinations of materials that were tested were SP + F and MP + F, each with and without Poron (P). Three samples of each were tested five times. Materials were heated and then compressed with an MTS servohydraulic device. Load transmission and percent compression at maximal load were measured on single materials and their combinations. Stress-strain curves were measured.

RESULTS

Compared to unheated material, the heated material transmitted higher forces. After heating, the combinations transmitted maximal load at a lower percentage of compression (i.e., became stiffer). Heating also changed the stress-strain curves of the three-material combinations, causing them to transmit maximal pressure at a lower strain.

CONCLUSION

Heating insole materials changed their mechanical properties. The materials became stiffer and less effective in the attenuation of applied forces.

CLINICAL RELEVANCE

The common practice of heating insole materials to improve their contact with the foot reduced the pressure-reducing properties of the materials, which may decrease their clinical effectiveness.

Improved ankle push-off power following cheilectomy for hallux rigidus: a prospective gait analysis study

BACKGROUND

There is limited objective scientific information on the functional effects of cheilectomy. The purpose of this study was to test the hypothesis that cheilectomy for hallux rigidus improves gait by increasing ankle push-off power.

METHODS

Seventeen patients with symptomatic Stage 1 or Stage 2 hallux rigidus were studied. Pre- and postoperative first metatarsophalangeal (MTP) range of motion and AOFAS hallux scores were recorded. A gait analysis was performed within 4 weeks prior to surgery and repeated at a minimum of 1 year after surgery. Gait analysis was done using a three-dimensional motion capture system and a force platform embedded in a 10-m walkway. Gait velocity sagittal plane ankle range of motion and peak sagittal plane ankle push-off power were analyzed.

RESULTS

Following cheilectomy, significant increases were noted for first MTP range of motion and AOFAS hallux score. First MTP motion improved an average of 16.7 degrees, from means of 33.9 degrees preoperatively to 50.6 degrees postoperatively (p<0.001). AOFAS hallux score increased from 62 to 81 (p<0.007). As demonstrated through gait anaylsis, a significant increase in postoperative peak sagittal plane ankle push-off power from 1.71±0.92 W/kg to 2.05±0.75 W/kg (p<0.04).

CONCLUSION

In addition to clinically increased range of motion and improved AOFAS Hallux score, first MTP joint cheilectomy produced objective improvement in gait, as measured by increased peak sagittal-plane ankle push-off power.

Changes in gait following the Scandinavian Total Ankle Replacement

BACKGROUND

There is a resurgence of popularity with regard to total ankle arthroplasty, although there are limited data documenting the effect of total ankle arthroplasty on ankle joint motion, gait, or ankle function. The purpose of this study was to perform a prospective evaluation of the effect of the Scandinavian Total Ankle Replacement on gait.

METHODS

We prospectively studied fifty consecutive patients with advanced ankle arthritis who underwent unilateral total ankle arthroplasty with the Scandinavian Total Ankle Replacement ankle prosthesis. Three-dimensional gait analysis was performed with use of a twelve-camera digital-motion capture system. Kinetic parameters were collected with use of two force plates. Temporal-spatial measurements included stride length and cadence. The kinematic parameters that were measured included the sagittal plane range of motion of the ankle, knee, and hip. The kinetic parameters that were studied included ankle plantar flexion-dorsiflexion moment and sagittal plane ankle power. The mean period of follow-up was forty-nine months (range, twenty-four to 108 months).

RESULTS

Temporal-spatial analysis showed that walking velocity increased as a function of increases in both cadence and stride length, and to significant levels for each. Kinematic analysis showed that ankle range of motion increased from a mean of 14.2° to 17.9° (p < 0.001), with the increase coming from increased plantar flexion. Increased motion was also measured at the hip and knee. Significant increases were found in ankle power (from 0.69 to 1.00 W/kg [p < 0.001]) and ankle plantar flexion moment (from 0.88 to 1.09 Nm/kg [p < 0.001]).

CONCLUSIONS

This study demonstrated that, at the time of intermediate-term follow-up and in comparison with the effects of ankle arthrodesis on gait as reported in previous studies, total ankle arthroplasty was associated with a more normal ankle function and a more normal gait, both kinetically and in terms of temporal-spatial parameters. More importantly, the study demonstrated marked improvement in multiple, objective parameters of gait following total ankle arthroplasty as compared with the patient's own preoperative function. The long-term maintenance of the gait improvements will require further study.

The adult sequelae of treated congenital clubfoot

There are limited studies about the incidence, nature, and severity of symptoms in adults with treated clubfoot; the rate at which symptoms increase and function diminishes with advancing age; and the appropriate treatments. One of the principles of treatment of these patients includes recognition that no one description of deformities applies to all cases of painful deformity in adults after childhood treatment of congenital clubfoot. There is a spectrum of the types of deformity and a range of severity among these that must be taken into account in the decision making regarding treatment. Although the level of symptoms is very variable and ankle and hindfoot arthrodeses have the disadvantage of increasing mechanical stress and subsequent arthritis in the midfoot, arthrodesis and, to a lesser degree, osteotomy remain the mainstays of surgical reconstruction in the adult with painful deformity after treatment of congenital talipes equinovarus.

Improvement in surgical consent with a preoperative multimedia patient education tool: a pilot study

BACKGROUND

Preoperative education and discussion is a crucial part of the surgeon-patient relationship. The purpose of this study was to assess the efficacy of a multimedia education tool to improve patients' understanding when used as an adjunct to the usual verbal consent process regarding first metatarsophalangeal joint (MTPJ) arthrodesis surgery.

MATERIALS AND METHODS

Thirty-one patients were prospectively recruited. There were 24 female and seven male patients with an average age of 56 years. Well-rehearsed, standardized and thorough information regarding the surgery, its risks, benefits, and usual post-operative course were supplied verbally to each patient. Patient understanding was then assessed with a condition specific questionnaire. Following this, each completed a multimedia educational program and repeated the questionnaire, including supplementary questions regarding ease of understanding and satisfaction with the two methods.

RESULTS

The patients answered 62% questions correctly before the multimedia presentation compared to 87% after it (p < 0.001). Patients rated the ease of understanding of the multimedia module as a median 9.3 cm along a 10-cm visual analogue scale and 9.1 cm when asked whether it contained the appropriate amount of information to make a decision about surgery. Ninety percent of patients considered that the multimedia tool answered their questions about surgery as well or better than the treating surgeon.

CONCLUSION

This study demonstrated that incorporation of a computer-based, multimedia education tool into to the surgical consent process improved patient understanding of the risks, benefits and usual postoperative course following first MTPJ arthrodesis surgery.

Hindfoot motion following reconstruction for posterior tibial tendon dysfunction

INTRODUCTION

Due to advances in technology, segmental gait analysis of the foot is now possible and can elucidate hindfoot deformity in persons with posterior tibial tendon dysfunction (PTTD). This study evaluated the motion of the hindfoot and ankle power following surgical reconstruction for PTTD utilizing a segmental foot model during gait.

MATERIALS AND METHODS

Twenty patients who underwent posterior tibial tendon reconstruction for Stage 2 PTTD using transfer of the flexor digitorum longus tendon to the navicular tuberosity, reconstruction of the calcaneo-navicular ligament complex, and a medial displacement calcaneal osteotomy were evaluated at a minimum followup of 1 year. Three-dimensional gait analysis was performed utilizing a 4-segment foot model. Temporal-spatial parameters included walking velocity, cadence, step length, and single support time. Sagittal, coronal, and transverse hindfoot motion with respect to the tibia/fibula and ankle power was calculated throughout the gait cycle.

RESULTS

Walking velocity, cadence, and step length were not significantly different between the study subjects and the normal control group. Study patients did show a significantly smaller single support time on both the affected and unaffected limbs compared to controls. There was no statistical difference in plantarflexion-dorsiflexion, varus-valgus, or ankle push-off power between the affected and unaffected sides of the study subjects, or between the affected side and the controls.

CONCLUSION

In this preliminary postoperative study, surgical reconstruction for PTTD effects quantifiable objective improvement in walking velocity, hindfoot motion and power.

Prospective controlled trial of STAR total ankle replacement versus ankle fusion: initial results

BACKGROUND

Mobile-bearing ankle replacements have become popular outside of the United States over the past two decades. The goal of the present study was to perform a prospective evaluation of the safety and efficacy of a mobile-bearing prosthesis to treat end stage ankle arthritis. We report the results of three separate cohorts of patients: a group of Scandanavian Total Ankle Replacement (STAR) patients and a control group of ankle fusion patients (the Pivotal Study Groups) and another group of STAR total ankle patients (Continued Access Group) whose surgery was performed following the completion of enrollment in the Pivotal Study.

MATERIALS AND METHODS

The Pivotal Study design was a non-inferiority study using ankle fusion as the control. A non-randomized multi-centered design with concurrent fusion controls was used. We report the initial perioperative findings up to 24 months following surgery. For an individual patient to be considered an overall success, all of the following criteria needed to be met: a) a 40-point improvement in total Buechel-Pappas ankle score, b) no device failures, revisions, or removals, c) radiographic success, and d) no major complications. In the Pivotal Study (9/00 to 12/01), 158 ankle replacement and 66 arthrodesis procedures were performed; in the Continued Access Study (4/02 to 10/06), 448 ankle replacements were performed, of which 416 were at minimum 24 months post-surgery at time of the database closure.

RESULTS

Major complications and need for secondary surgical intervention were more common in the Pivotal Study arthroplasty group than the Pivotal Study ankle fusion group. In the Continued Access Group, secondary procedures performed on these arthroplasty patients decreased by half when compared with the Pivotal Arthroplasty Group. When the Pivotal Groups were compared, treatment efficacy was higher for the ankle replacement group due to improvement in functional scores. Pain relief was equivalent between fusion and replacement patients. The hypothesis of non-inferiority of ankle replacement was met for overall patient success.

CONCLUSION

By 24 months, ankles treated with STAR ankle replacement (in both the Pivotal and Continued Access Groups) had better function and equivalent pain relief as ankles treated with fusion.

Surgical aspects of the diabetic foot

A comprehensive review of the literature relating to the pathology and management of the diabetic foot is presented. This should provide a guide for the treatment of ulcers, Charcot neuro-arthropathy and fractures involving the foot and ankle in diabetic patients.

Physical properties, durability, and energy-dissipation function of dual-density orthotic materials used in insoles for diabetic patients

BACKGROUND

Patients with neuropathic conditions may develop plantar bony deformities through neuropathic collapse, frequently placing the skin and soft tissues at risk. Orthoses have been used to accommodate and distribute plantar pressures over a large surface area, thereby minimizing peak loading pressures in small regions and reducing the risk of ulceration.

METHODS

A previously described bony prominence model (Brodsky et al.) was used to test the pressure-absorbing and force-transmission properties of various orthotic material combinations used in our outpatient clinic. Six materials were tested in five combinations of materials for their compressive properties: [MS]: medium plastazote (M) + soft plastazote (S); [MN]: medium plastazote (M) + nickelplast (N); [NP] nickelplast (N) + Poron (P); [MO] medium plastazote (M) + Spenco (O); and [MC] medium plastazote (M) + P-cell (C). Materials were tested for 100,000 cycles using a materials-testing system (MTS) apparatus (MTS Systems Corporation, Cary, NC) and software. Stress-strain curves comparing the measured peak pressure to the elastic deformation, or the percentage of compression a material experiences with respect to its original thickness, were plotted for each orthotic combination.

RESULTS

For MS, MN, MO, and to a lesser extent, MC, a trend was noted for decreased elastic deformation with increased testing. Additionally, the peak pressures before and after testing for each 10,000 testing cycle for each of the orthotic combinations were plotted. For both MN and NP, no demonstrable difference was noted in the peak pressures in the pretesting and post-testing for the 100,000 cycles. The MO showed a trend for increased peak pressures after each testing cycle. Both the MC and MS peak pressures markedly increased with respect to pretesting value. Also, the MN, MO, and MS all showed an overall trend for increased load cell values with increasing cycles at fast loading.

CONCLUSIONS

These data showed that some orthotic combinations are more effective than others at reducing peak pressures during compression testing using our bony prominence model. Further studies are needed to test the orthotic combinations for shear and combined shear and compression modes.