Ankle arthritis

[Medial pain syndrome in patients with total ankle replacement]

Total ankle replacement is an increasingly recommended treatment for patients with end-stage ankle osteoarthritis. The increasing experience with this procedure explains its acceptance as a therapeutic option in complex cases as part of reconstruction surgery. However, the complication rate including failure of the prosthesis should not be underestimated. Previous studies have shown that most patients developed ankle osteoarthritis secondary to previous trauma. Patients with posttraumatic osteoarthritis often have varus or valgus misalignment of the hindfoot. In cases with incorrectly addressed hindfoot misalignment and/or incorrectly positioned prosthesis components, pain may remain postoperatively because of biomechanical dysbalance and asymmetrical load. The pain is mostly localized on the medial side the so-called medial pain syndrome.The following classification of the medial pain syndrome has been established in our practice: type I medial impingement/contracture of medial ligaments, type II valgus deformity, type III varus deformity, type IV combined varus-valgus deformity.

The effect of three weekly intra-articular injections of hyaluronate on pain, function, and balance in patients with unilateral ankle arthritis

BACKGROUND

Ankle arthritis can cause substantial pain and functional limitation. Previous studies have indicated that five weekly intra-articular injections of hyaluronate were safe and effective in the treatment of ankle osteoarthritis. The purpose of this study was to evaluate the effect and safety of three weekly injections of hyaluronate in patients with unilateral ankle arthritis.

METHODS

Fifty patients who had had unilateral ankle pain for at least six months and were classified radiographically as having Kellgren-Lawrence grade-2 or 3 ankle arthritis were recruited for a prospective study. Patients received three weekly intra-articular injections of hyaluronate. The primary outcome was the change in the Ankle Osteoarthritis Scale score at six months after the third injection. Secondary outcomes included the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Score, four clinical tests of balance, consumption of rescue analgesics, and global patient satisfaction.

RESULTS

Forty-six participants completed the study. A significant reduction in the mean Ankle Osteoarthritis Scale score was noted at one, three, and six months after the third injection (p < 0.05 for each follow-up visit compared with baseline). The mean AOFAS Ankle-Hindfoot Score improved from 60.5 points at baseline to 73.5, 75.5, and 76.7 points at one, three, and six months of follow-up, respectively (p < 0.05). The patients demonstrated significant improvement on all four balance tests at each follow-up visit (p < 0.05 for each test compared with baseline). Acetaminophen consumption dropped significantly following treatment (p < 0.05). The patients' satisfaction rate was high, and no serious adverse events were reported.

CONCLUSIONS

This study suggests that three weekly injections of hyaluronate are well-tolerated and can provide pain relief and improve function and balance in patients with unilateral ankle arthritis. Larger controlled trials with longer follow-up are necessary to verify the effects of hyaluronate in the treatment of ankle arthritis.

Arthroplasty versus arthrodesis for end-stage ankle arthritis: decision analysis using Markov model

BACKGROUND

Total ankle arthroplasty and arthrodesis are the two mainstreams of treatment for end-stage ankle arthritis. This study was performed to determine which is a better choice for ankle arthritis, using a decision analysis and Markov model to reflect the repetitive nature of revision arthroplasty.

METHODS

Based on current published evidence, a decision tree was constructed to compare the clinical outcomes of total ankle arthroplasty and arthrodesis, which contained the possible clinical events and the probabilities. Total ankle arthroplasty was subject to revision arthroplasty, and a Markov model was adopted for this branch to reflect this repetitive trait of the procedure. Arthrodesis could cause adjacent arthritis, and a conventional decision analysis model was adopted for this branch. Quality well-being index score was used for clinical outcome assessment, which was the utility in the decision tree. Sensitivity analysis was performed to test the stability of the decision tree and the threshold values.

RESULTS

The model favoured total ankle arthroplasty over arthrodesis in terms of quality well-being index score. Sensitivity analysis showed that the model was considerably stable, unaffected by the changes in probabilities of failure after total ankle arthroplasty and adjacent arthritis after arthrodesis.

CONCLUSIONS

Based on current evidence, total ankle arthroplasty was found to be a better treatment than arthrodesis for ankle arthritis. Future development in the implant materials, improved understanding of ankle biomechanics, and surgical techniques will further enhance the clinical outcome of total ankle arthroplasty.

Revision rates after total ankle arthroplasty in sample-based clinical studies and national registries

BACKGROUND

The aim of this study was to evaluate the outcome of specific implants in total ankle arthroplasty as reported in clinical studies and determined by national registries.

MATERIALS AND METHODS

A structured literature review was conducted regarding sample-based clinical studies and national registry data. To allow for comparative analyses, registry data had to be available for the implants included. These were STAR Ankle, Büchel-Pappas, Hintegra, Mobility, Agility, and Ramses Total Ankle Arthroplasty. The revision rate was used as the main outcome parameter.

RESULTS

On average, the revision rates published in sample-based clinical studies were about half the value found in registries. Implant developers represent a share of almost 50% of the published content and are therefore over-represented in scientific publications. The inventors of STAR Ankle and BP total ankle implants published data which was statistically significantly superior to the outcome achieved in average patients as documented in registries. Irrespective of the implant, the average revision rate to be expected according to the registry data available is 21.8% after 5 years, and 43.5% after 10 years.

CONCLUSION

The average revision rate published in peer-reviewed scientific articles was significantly lower than the outcome achieved according to national arthroplasty registry data, which reflect actual average patient care in the respective countries. Publications by some research groups, particularly by implant inventors, show a deviation from the outcome published by other users and those shown in registry data.

Numerical simulation of strain-adaptive bone remodelling in the ankle joint

BACKGROUND

The use of artificial endoprostheses has become a routine procedure for knee and hip joints while ankle arthritis has traditionally been treated by means of arthrodesis. Due to its advantages, the implantation of endoprostheses is constantly increasing. While finite element analyses (FEA) of strain-adaptive bone remodelling have been carried out for the hip joint in previous studies, to our knowledge there are no investigations that have considered remodelling processes of the ankle joint. In order to evaluate and optimise new generation implants of the ankle joint, as well as to gain additional knowledge regarding the biomechanics, strain-adaptive bone remodelling has been calculated separately for the tibia and the talus after providing them with an implant.

METHODS

FE models of the bone-implant assembly for both the tibia and the talus have been developed. Bone characteristics such as the density distribution have been applied corresponding to CT scans. A force of 5,200 N, which corresponds to the compression force during normal walking of a person with a weight of 100 kg according to Stauffer et al., has been used in the simulation. The bone adaptation law, previously developed by our research team, has been used for the calculation of the remodelling processes.

RESULTS

A total bone mass loss of 2% in the tibia and 13% in the talus was calculated. The greater decline of density in the talus is due to its smaller size compared to the relatively large implant dimensions causing remodelling processes in the whole bone tissue. In the tibia, bone remodelling processes are only calculated in areas adjacent to the implant. Thus, a smaller bone mass loss than in the talus can be expected. There is a high agreement between the simulation results in the distal tibia and the literature regarding.

CONCLUSIONS

In this study, strain-adaptive bone remodelling processes are simulated using the FE method. The results contribute to a better understanding of the biomechanical behaviour of the ankle joint and hence are useful for the optimisation of the implant geometry in the future.

Effect of supramalleolar varus and valgus deformities on the tibiotalar joint: a cadaveric study

BACKGROUND

Distal tibia coronal plane malalignment predisposes the ankle joint to asymmetric load. The purpose of this cadaveric study was to quantify changes in pressure and force transfer in an ankle with a supramalleolar deformity.

MATERIALS AND METHODS

Seventeen cadaveric lower legs were loaded with 700 N after creating supramalleolar varus and valgus deformities. The fibula was left intact in 11 specimens and osteotomized in six. Tekscan© sensors were used to measure the tibiotalar pressure characteristics.

RESULTS

In isolated supramalleolar deformity, the center of force and peak pressure moved in an anteromedial direction for valgus and posterolateral direction for varus deformities. The change was in an anteromedial direction for varus and in a posterolateral direction for valgus deformities in specimens with an osteotomized fibula.

CONCLUSION

Two essentially different groups of varus and valgus deformities of the ankle joint need to be distinguished. The first group is an isolated frontal plane deformity and the second group is a frontal plane deformity with associated incongruency of the ankle mortise.

CLINICAL RELEVANCE

Our findings underline the complexity of asymmetric osteoarthritis of the ankle joint. In addition, results from this study provide useful information for future basic research on coronal plane deformity of the hindfoot and for determining appropriate surgical approaches.

Stresses in the ankle joint and total ankle replacement design

The ankle is a highly congruent joint with a surface area of 11-13 cm(2). Total ankle replacements have been attempted since the early 1970s and design has continually evolved as the early designs were a failure. This was because the stresses involved and the mutiaxial motion of the ankle has not been understood until recently. It has been shown that the talus slides as well as rolls during the ankle arc of motion from plantarflexion to dorsiflexion. Furthermore, the articular surfaces and the calcaneofibular and tibiocalcaneal ligaments have been shown to form a four bar linkage dictating ankle motion. A new design ankle replacement has been suggested recently which allows multiaxial motion at the ankle while maintaining congruency throughout the arc of motion. The early results of this ankle replacement have been encouraging without any reported failures due to mechanical loosening.

Arthroscopic ankle arthrodesis after tibial pilon open reduction internal fixation

Ankle arthrodesis is an essential tool in the foot and ankle surgeon's armamentarium. Despite the evolving technology and ongoing research in ankle arthroplasty, arthrodesis continues to be a proven and safe option for the majority of patients with ankle arthritis refractory to conservative management. Here, the authors present their technique of an arthroscopic ankle arthrodesis specifically in the setting of a previous open-reduction internal fixation (ORIF) for a tibia plafond type fracture. They have found this to be a reliable technique to achieve a solid ankle arthrodesis while minimizing soft-tissue trauma and dissection in an already compromised soft-tissue envelope.

Comparative study of the quality of life between arthrodesis and total arthroplasty substitution of the ankle

Our goal was to compare the health status of patients with primary and secondary arthrosis of the ankle before and after arthrodesis or total substitution arthroplasty, and to determine the improvement in quality of life and whether there is any difference between these techniques. A prospective comparative study of clinical-functional evaluation was performed using the American Orthopaedic Foot & Ankle Society (AOFAS) scale and quality of life with the short form (SF)-36 questionnaire in patients who underwent arthrodesis (16 cases) or total substitution arthroplasty of the ankle (14 cases) after 2 years (mean, 25.2 months) of follow-up after surgery, in comparison with the baseline preoperative status. In this series of comparable patients, both techniques showed a statistically significant improvement with regard to the clinical evaluation and quality of life after 2 years of follow-up; the arthrodesis group increased from mean AOFAS values of 37.12 to 45.62 (P = .055) and mean SF-36 values of 32.96 to 46.25 (P = .008), whereas in the arthroplasty group the mean values of AOFAS increased from 33 to 62 (P = .024) and SF-36 from 33.62 to 59.84 (P = .001). Nevertheless, in all cases the improvement was statistically greater in patients who underwent arthroplasty than in those who underwent arthrodesis (P = .048 for AOFAS, and P = .026 for SF-36). In conclusion, arthrodesis and arthroplasty represent good options in the surgical treatment of ankle arthrosis, providing both a significant improvement in function and in the health perception and quality of life of the patient. New-generation total ankle substitution arthroplasty provides an improvement in the quality of life and perception of general health of the patient with arthrosis of this joint, when this technique is compared with surgical fusion.

Impact of complications in total ankle replacement and ankle arthrodesis analyzed with a validated outcome measurement

BACKGROUND

Major modifications in the design and techniques of total ankle replacement have challenged the perception that ankle arthrodesis is the treatment of choice for end-stage ankle arthritis. High complication and revision rates have been reported after both procedures.

METHODS

We performed radiographic evaluations at a mean of thirty-nine months following 114 total ankle replacements done with use of commonly used implants and at a mean of thirty-seven months following forty-seven ankle arthrodeses. The mean age was sixty-four years for the patients (fifty-one female and sixty-three male) who underwent total ankle replacement and fifty-nine years in the patients (fifteen female and thirty-two male) who underwent ankle arthrodesis. The impact of complications was analyzed with use of the Ankle Osteoarthritis Scale (AOS), a validated outcome instrument.

RESULTS

Both groups had significant improvement in the mean AOS score (p < 0.001). There was no significant difference in the mean improvement between the two groups (p = 0.96). The complication rate was 54% following total ankle replacement and 26% following ankle arthrodesis, which was a significant difference (p = 0.003). The impact of major complications on the AOS outcome score was significant in both the total ankle replacement group (p = 0.031) and the ankle arthrodesis group (p = 0.02).

CONCLUSIONS

At the time of follow-up, at a minimum of two years postoperatively, the outcomes of total ankle replacement and ankle arthrodesis, with regard to pain relief and function, were comparable. While the rate of complications was significantly higher following total ankle replacement, the impact of complications on outcome was clinically relevant in both groups.

Outcome evaluation of ankle osteoarthritis treatments: plantar pressure analysis during relatively long-distance walking

BACKGROUND

This study aimed to use plantar pressure analysis in relatively long-distance walking for objective outcome evaluation of ankle osteoarthritis treatments, i.e., ankle arthrodesis and total ankle replacement.

METHODS

Forty-seven subjects in four groups: three patient groups and controls, participated in the study. Each subject walked twice in 50-m trials. Plantar pressure under the pathological foot was measured using pressure insoles. Six parameters: initial contact time, terminal contact time, maximum force time, peak pressure time, maximum force and peak pressure were calculated and averaged over trials in ten regions of foot. The parameters in each region were compared between patient groups and controls and their effect size was estimated. Besides, the correlations between pressure parameters and clinical scales were calculated.

FINDINGS

We observed based on temporal parameters that patients postpone the heel-off event, when high force in forefoot and high ankle moment happens. Also based on maximum force and peak pressure, the patients apply smoothened maximum forces on the affected foot. In ten regions, some parameters showed improvements after total ankle replacement, some showed alteration of foot function after ankle arthrodesis and some others showed still abnormality after both surgical treatments. These parameters showed also significant correlation with clinical scales in at least two regions of foot.

INTERPRETATION

Plantar pressure parameters in relatively long-distance trials showed to be strong tools for outcome evaluation of ankle osteoarthritis treatments.

A systematic review of radiographic definitions of foot osteoarthritis in population-based studies

OBJECTIVE

To identify the methods used in population-based epidemiological studies to diagnose radiographic foot osteoarthritis (OA) and to estimate the population prevalence of radiographic foot OA.

METHOD

Electronic databases searched included Medline, Embase, CINAHL and Ageline (inception to May 2009). The search strategy combined search terms for radiography, OA, foot, and specific foot joints. Predetermined selection criteria were applied. Data extracted from each paper included: sample population, radiographic views taken, foot joints examined, scoring system used, definition of OA applied, reliability of radiographic scoring and prevalence of radiographic OA in the foot.

RESULTS

Titles and abstracts of 1035 papers were reviewed and full-texts of 21 papers were obtained. Fifteen papers met inclusion criteria and a further 12 papers were included after screening references. Radiographic views were frequently not specified (NS) but a combination of antero-posterior (AP) and lateral (Lat) views was most commonly reported. The first metatarsophalangeal (MTP) joint was the most commonly examined joint (n=20, 74%). Nineteen studies (70%) used the Kellgren and Lawrence (K&L) grading system, 95% of which defined OA as K&L grade> or =2. Estimates of the prevalence of radiographic first MTP joint OA (defined as K&L> or =2) in middle-aged to older adults ranged from 6.3 to 39%. Significant statistical heterogeneity prevented pooling of prevalence estimates.

CONCLUSION

There are comparatively few studies examining radiographic foot OA. Existing studies mainly focus on the first MTP joint and use the K&L grading system. Future studies are needed to quantify the prevalence of radiographic OA at the different joint complexes within the foot.

Impact of talar component rotation on contact pressure after total ankle arthroplasty: a cadaveric study

BACKGROUND

There is limited literature available to assess the impact of talar component rotation on total ankle contact biomechanics.

MATERIALS AND METHODS

Six male cadaveric below-knee specimens were implanted with Agility(R) total ankles. The sequence of talar rotation for each specimen was randomized between: Neutral, 7.5 degrees internal and 7.5 degrees external rotation. Contact pressure was measured using Tekscan ankle sensors during sequential static axial loadings and 10 simulated dynamic strides under 650 N axial load.

RESULTS

The peak pressure (PP) increased for the internally (PP(static)=7.0 +/- 0.27 MPa (mean +/- SD), p < 0.001; PP(dynamic)=7.8 +/- 0.22 MPa, p = 0.001) and externally rotated talar component positions (PP(static)=6.2 +/- 0.22 MPa, p = 0.011; PP(dynamic)=7.6 +/- 0.29 MPa, p = 0.004) as compared to neutral (PP(static) =5.5 +/- 0.13 MPa; PP(dynamic) = 6.3 +/- 0.11 MPa). The contact area under 650 approximately N load was reduced for both talar component internal (97.38 +/- 17.7 mm(2), p = 0.001) and external rotation (152.66 +/- 16.8 mm(2), p = 0.022) as compared to neutral (190.02 +/- 13.8 mm(2)). There was a significant rotational torque for the malrotated talar components as compared to neutral, that increased with axial loading (p = 0.044).

CONCLUSION

Near the extremes of talar malrotation, there was a consistent change from a continuous tibiotalar contact area to a pattern of two-point contact; the orientation of which opposed the direction of talar component malrotation. Talar component malrotation resulted in: increased peak pressure, decreased contact area and increased rotational torque that resisted the malrotation.

CLINICAL RELEVANCE

Talar component malrotation may contribute to premature polyethylene wear as well as potential talar loosening secondary to the rotational torque generated as the geometry of the prosthesis attempts to seek congruency.

Surgery on the rheumatoid ankle joint: efficacy versus effectiveness

This article examines synovectomy and ankle arthrodesis for the rheumatoid ankle joint. Reviews of osteoimmunology and gait analyses specific to rheumatoid arthritis are included. Comparison studies including ankle arthrodesis and total ankle arthroplasty are reviewed.

Tibiotalar nonunion corrected by hindfoot arthrodesis

A 65-year-old man without significant comorbidities was referred to the senior author (EG) 9 months after an ankle arthrodesis procedure with complaints of pain, swelling, and progressive hindfoot valgus. The patient had elected to have the index surgery because of severe ankle arthritis due to longstanding lateral ankle instability. Physical examination revealed a well-healed anterior, midline ankle incision with normal pulses and sensation. Painful, limited ankle and subtalar range of motion was noted along with 20 degrees of hindfoot valgus and subfibular impingement. Radiographs of the ankle revealed an attempted ankle fusion using a knee arthroplasty trabecular metal augment placed vertically at the tibiotalar joint. There were no screws or other hardware present to provide compression and stability of the fusion. A computed tomography scan showed a tibiotalar nonunion, erosion of the talar body, and severe tibiotalar and subtalar arthritis. Inflammatory markers were within normal range. Based on the findings of a failed fusion and progressive painful hindfoot deformity, it was determined that the patient would benefit from removal of the hardware and revision fusion surgery. Tibiotalocalcaneal (TTC) hindfoot fusion was planned because of the patient's talar collapse and tibiotalar/ subtalar arthritis. The TTC procedure was performed with a retrograde intramedullary nail, femoral head allograft, and morselized fibular autograft enriched with platelet-rich plasma. The femoral head was used as a structural allograft to fill the large bone defect, prevent limb shortening, and assist in correction of the hindfoot deformity. Intraoperative findings revealed severe metallic synovitis of the ankle and subtalar joints, metal debris at the site of the trabecular implant, and segmental defects of the distal tibia and talus. Weight bearing was permitted after 16 weeks when evidence of successful ankle fusion was confirmed radiographically. At 24 months, the patient was pain free and ambulating without difficulty.

Inter- and intraobserver reliability of the COFAS end-stage ankle arthritis classification system

BACKGROUND

End-stage ankle arthritis should have an appropriate classification to assist surgeons in the management of end-stage ankle arthritis. Outcomes research also requires a classification system to stratify patients appropriately.

MATERIALS AND METHODS

Six fellowship trained foot and ankle surgeons met on two occasions to derive a classification system for end-stage ankle arthritis. A four-part classification system was designed. Four surgeons reviewed blinded patient profiles and radiographs on two occasions to determine the inter- and intraobserver reliability.

RESULTS

Good interobserver reliability (kappa = 0.62) and intraobserver reproducibility (kappa = 0.72) was demonstrated for the classification system.

CONCLUSION

The COFAS classification system appears to be a valid tool for the management and research of end-stage ankle arthritis.

Bipolar fresh osteochondral allograft of the ankle

BACKGROUND

Severe post-traumatic ankle arthritis poses a reconstructive challenge in the young and active patient. Bipolar fresh osteochondral allograft (BFOA) may represent an intriguing alternative to arthrodesis and prosthetic replacement. The aim of this study was to describe a lateral trans-malleolar technique for BFOA, and to evaluate the results in a case series.

MATERIALS AND METHODS

From 2004 to 2006, 32 patients, mean age of 36.8 +/- 8.4 years, affected by ankle arthritis underwent BFOA with a mean followup of 31.2 months. The graft was prepared by specifically designed jigs, including the talus and the tibia with the medial malleolus. The host surfaces were prepared by the same jigs through a lateral approach. The graft was placed and fixed with twist-off screws. Patients were evaluated clinically and radiographically at 2, 4, and 6 month after operation, and at a minimum 24 months followup. A biopsy of the grafted areas was obtained from 7 patients at 1-year followup for histological and immunohistochemical examination.

RESULTS

Preoperative AOFAS score was 33.1 +/- 10.9 and postoperatively 69.5 +/- 19.4 (p < 0.0005). Six failures occurred. Cartilage harvests showed hyaline-like histology with a normal collagen component but low proteoglycan presence and a disorganized structure. Samples were positive for MMP-1, MMP-13 and Capsase-3.

CONCLUSION

The use of BFOA represents an intriguing alternative to arthrodesis or arthroplasty. We believe precise allograft sizing, stable fitting and fixation and delayed weightbearing were key factors for a successful outcome. Further research regarding the immunological behavior of transplanted cartilage is needed.

Achilles lengthening procedures

Contracture of the gastrocnemius-soleus complex with equinus deformity is a common hindfoot condition. In children, it is frequently associated with neuromuscular conditions such as cerebral palsy. In the adult population, it is linked to numerous pathologies such as adult-acquired flatfoot, diabetic neuropathic ulcers, and plantar fasciitis. With the medial column reduced, failure to achieve 10 degrees of passive ankle dorsiflexion with the knee flexed and extended suggests a contracture. This article reviews the anatomical and evolutionary basis for human foot structure, implications of tight gastrocnemius, and specific disease states. Operative releases for lengthening, including proximal gastrocnemius recession, tendo-Achilles lengthening, and endoscopic recession, are detailed.

SPECT-CT compared with conventional imaging modalities for the assessment of the varus and valgus malaligned hindfoot

The combined single-photon emission computed tomography and conventional computed tomography (SPECT/CT) technique has increased the sensitivity and specificity of bone scans. We examined the value of using SPECT/CT for the assessment of coronal plane hindfoot deformities. Twenty-seven patients with varus (11 patients) or valgus (16 patients) malalignment of the hindfoot were assessed using radiography, conventional CT, bone scintigraphy, and SPECT/CT. The amount of deformity, stage of osteoarthritis, and level of activation on bone scans and SPECT/CT were measured. Activation was assessed in 12 regions of interest. The stage of osteoarthritis seen on plain radiographs correlated significantly with the level of activation detected on bone scans (p < 0.05). No correlation was observed between the amount of deformation and activity, and between bone scan activation and signs of osteoarthritis on CT scans. The varus malaligned ankles showed higher radioisotope uptake in the medial areas, while the valgus malaligned ankles showed increased uptake in the lateral areas (p < 0.05). SPECT/CT may be a valuable tool for the assessment and staging of osteoarthritis. Our findings underline the adverse effects of coronal plane deformity of the hindfoot. In addition, results from this study provide useful information for future basic research on coronal plane deformity of the hindfoot and for determining appropriate surgical approaches.

Effect of post-traumatic tibiotalar osteoarthritis on kinematics of the ankle joint complex

BACKGROUND

Knowledge of joint kinematics in the healthy and diseased joint may be useful if surgical techniques and joint replacement designs are to be improved. To date, little is known about the kinematics of the arthritic tibiotalar joint and its effect on the kinematics of the subtalar joint.

MATERIALS AND METHODS

Kinematics of the ankle joint complex (AJC) were measured in six patients with unilateral post-traumatic tibiotalar osteoarthritis in simulated heel strike, midstance and toe off weight bearing positions using magnetic resonance and dual fluoroscopic imaging techniques. The kinematic data obtained was compared to a normal cohort from a previous study.

RESULTS

From heel strike to midstance, the arthritic tibiotalar joint demonstrated 2.2 +/- 5.0 degrees of dorsiflexion while in the healthy controls the tibiotalar joint plantarflexed 9.1 +/- 5.3 degrees (p < 0.01). From midstance to toe off, the subtalar joint in the arthritic group dorsiflexed 3.3 +/- 4.1 degrees whereas in the control group the subtalar joint plantarflexed 8.5 +/- 2.9 degrees (p < 0.01). The subtalar joint in the arthritic group rotated externally 1.2 +/- 1.0 degrees and everted 3.3 +/- 6.1 degrees from midstance to toe off while in the control group 12.3 +/- 8.3 degrees of internal rotation and 10.7 +/- 3.8 degrees eversion (p < 0.01 and p < 0.01, respectively) was measured.

CONCLUSION

The current study suggests that during the stance phase of gait, subtalar joint motion in the sagittal, coronal, and transverse rotational planes tends to occur in an opposite direction in subjects with tibiotalar osteoarthritis when compared to normal ankle controls. This effectively represents a breakdown in the normal motion coupling seen in healthy ankle joints.

CLINICAL RELEVANCE

Knowledge of ankle kinematics of arthritic joints may be helpful when designing prostheses or in assessing the results of treatment interventions.

Anterior double plating for rigid fixation of isolated tibiotalar arthrodesis

BACKGROUND

Arthrodesis is the most common procedure used to treat end-stage osteoarthritis of the ankle, particularly in patients with difficult conditions such as poor bone quality. While many techniques are available to fuse the ankle, current recommendations favor the use of internal fixation with screws and/or plates. Despite of progress, the complication rate remains a major concern. Non-union is one difficult problem especially with difficult bone conditions, particularly the loss of bone stock on the talar side. Therefore, fusion of the tibiotalar joint is often extended to the talocalcaneal joint to provide sufficient stability. To preserve the subtalar joint, an anterior double plate system for rigid fixation of isolated tibiotalar arthrodesis was developed. This is a preliminary report on the clinical and radiological outcome with this technique.

MATERIALS AND METHODS

Twenty-nine patients (15 men, 14 women; one ankle per patient) were treated from October 2006 to September 2007. We converted 16 ankles with osteoarthritis and difficult bone conditions, four non-united ankle arthrodeses, and nine failed total ankle replacements to an isolated tibiotalar arthrodesis using anterior double plating. If necessary, we used solid allograft to fill bony defects. Outcomes included bone union as assessed by radiographs, pain as indicated by the American Orthopaedic Foot and Ankle Society scores, and patient satisfaction.

RESULTS

Solid arthrodesis was achieved after an average of 12.3 (eight to 26) weeks in the 16 ankles without bone graft interposed between the tibia and talus, and 14.3 (range, 8 to 26) weeks in the 13 ankles with interpositional bone allograft. Radiographs showed that the position of arthrodesis obtained at the time of surgery did not change in any patient up to one year after surgery. The mean American Orthopaedic Foot and Ankle Society (AOFAS) Hindfoot Score increased from 37 (range, 20 to 63) preoperatively to 68 (range, 50 to 92) at the last followup. Twenty-seven patients (93%) were satisfied with their outcome and indicated they would have the operation again. No complications were noted.

CONCLUSION

The anterior double plating system was shown be a reliable method to achieve solid isolated tibiotalar arthrodesis, even in ankles with difficult conditions such as loss of bone stock due to failed total ankle arthroplasty.

Etiology of ankle osteoarthritis

The purpose of this study was to evaluate the distribution rate of etiologies leading to ankle arthritis and to quantify and compare the important clinical and radiologic variables among these etiologic groups. We evaluated data from 390 patients (406 ankles) who consulted our center because of painful end-stage ankle osteoarthritis (OA) by using medical history, physical examination, and radiography. Posttraumatic ankle OA was seen in 78% of the cases (n = 318), secondary arthritis in 13% (n = 52), and primary OA in 9% (n = 36). The average American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score was 38 points (range, 0-74 points), range of motion was 22 degrees (range, 0 degrees-65 degrees), and visual analog scale for pain was 6.8 (range, 2-10). Patients with posttraumatic end-stage ankle OA were younger than patients with primary OA. The average tibiotalar alignment was 88 degrees (range, 51 degrees-116 degrees) and did not differ between the etiologic groups. Our study showed trauma is the main cause of ankle OA and primary OA is rare. In the majority of patients with ankle OA the average tibiotalar alignment is varus regardless of the underlying etiology.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Management of complications of open reduction and internal fixation of ankle fractures

The management of complications resulting from the open reduction and internal fixation of ankle fractures is discussed in detail. The initial radiographic findings of the most common postsurgical complications of ankle fracture reduction are briefly discussed, namely lateral, medial, and posterior malleolar malunion or nonunion, syndesmotic widening, degenerative changes, and septic arthritis with or without concomitant osteomyelitis. Emphasis is placed on the management of these complications, with a review of the treatment options proposed in the literature, a detailed discussion of the authors' recommendations, and an inclusion of different case presentations.

History and evolution in total ankle arthroplasty

INTRODUCTION

The current study provides an overview of history and evolution in total ankle arthroplasty.

METHODS

We conducted a comprehensive literature search without limitations to language. Information from any source, providing evidence of the use ankle of prostheses (e.g. biomechanical testing, cadaveric implantations or clinical use) was evaluated. Data regarding biomechanical concepts, design considerations, published results (patient numbers, surgical method, follow-up, complications and survival rates) were collected.

RESULTS

Only level IV studies were found. Mobile-bearing prostheses are mainly used in Europe, and fixed-bearing implants are mainly used in the USA. The current designs' failure rate is 10-12% at approximately 5 years. Survival rates vary among different institutions. Increased surgeons' experience is associated with better outcomes.

DISCUSSION

Biomechanical studies and review of previous implant failures has led to the development of a new generation of implants.

CONCLUSIONS

Results show that ankle arthroplasty is a viable alternative for the management of ankle arthritis in selected patients.

Posttraumatic ankle osteoarthritis after ankle-related fractures

OBJECTIVES

The present study analyzes etiologies, pathomechanisms, and predisposing factors that lead to the development and progression of posttraumatic ankle osteoarthritis (OA) after ankle-related fractures.

DESIGN

Retrospective cohort study.

SETTING

Tertiary health care center.

PATIENTS

The underlying cohort was 257 painful end-stage ankle OA patients (270 cases) presenting to the authors' clinic. Patients from this cohort with a history of ankle-related fracture (141 patients) were evaluated.

INTERVENTION

Analysis of individual clinical and radiologic history since the time of injury; physical and radiologic examination at the time of ankle OA.

MAIN OUTCOME MEASURES

OA latency time, fracture type, treatment methods, complication of fracture healing, soft tissue situation, age, pain score, American Orthopedic Foot and Ankle Society ankle score, range of motion, radiologic tibiotalar alignment, and radiologic ankle OA grading were evaluated.

RESULTS

The latency time between injury and end-stage ankle OA was 20.9 years (1-52 years). Malleolar fracture was the most common fracture (53.2%). A negative correlation of the OA latency time with the fracture severity was observed for some fracture types (pilon fractures, r = -0.4, P < 0.01). Patients with complications during the healing process showed significantly shorter OA latency time (P < 0.01). The patients' age at time of injury correlated negatively with the OA latency time (r = -0.6, P < 0.01).

CONCLUSIONS

The present study addresses the link between ankle-related fractures and secondary posttraumatic ankle OA. The latency time between injury and OA depends on fracture type and severity, occurrence of complications in the healing process, and patient-related factors, for example, age.

High inter-specimen variability of baseline data for the tibio-talar contact area

BACKGROUND

The tibio-talar contact area has been widely investigated to monitor biomechanical changes due to articular incongruities or an altered loading. This study aims to investigate for the first time in a systematic way the extent of the inter-specimen variability of the tibio-talar contact area, and its repercussions when analyzing data concerning this parameter.

METHODS

Ten specimens were loaded to record the tibio-talar contact characteristics by use of pressure sensitive film. The size of the talar dome area, the size of the (normalized) tibio-talar contact area, the position of the tibio-talar contact area, and the shape of the latter were determined and analyzed. Inter-specimen variability was expressed as the coefficient of variation and was calculated for the datasets of previous studies as well.

FINDINGS

The size of the tibio-talar contact area showed a very high inter-specimen variability, as is the case in previous studies. This high variability persisted when a normalized tibio-talar contact area was calculated. The shape of the tibio-talar contact area showed some basic characteristics, but a high variation in details could be observed.

INTERPRETATION

Every specimen can be considered to have its own "ankle print". By this variability, articular incongruities are expected to have a different effect on local biomechanical characteristics in every single individual. Therefore, every single case has to be evaluated and reported for significant changes. In case of modeling, this also underscores the need to use subject specific models fed by sets of parameters derived from a series of single specimens.

Repeatability and contact stress gradient detection of sealed pressure-sensitive film when used in a physiological joint model

Sealed pressure-sensitive film is frequently used to record contact characteristics in physiological joints. However, the effect on the pressure-recording characteristics of sealing the film when used in these circumstances has never been studied. This study compares the coefficient of variation, the standardized coefficient of variation, the tangent and secant contact stress gradients, and the actual pressures between unsealed and sealed Fuji film, in a simplified physiological joint model with a full-thickness surface defect. Unsealed film and sealed film were loaded through a range of nominal loads and the resulting stains were analysed by use of custom-made macros for the ImageJ image-processing program. The coefficient of variation did not exceed 5.7 per cent (sealed film), and the standardized coefficient of variation did not exceed 1.8 per cent (unsealed and sealed film). Contact stress gradients did not differ significantly. The recorded pressure at the level of surface defects was always about 0.2 MPa higher in the case of sealed film, and therefore predictable. It is concluded that sealing the film will not change the pressure-recording characteristics.

Use of circular external fixation for combined subtalar joint fusion and ankle distraction

The authors discuss a novel technique not previously published that incorporates a subtalar joint arthrodesis with an ankle joint arthrodiastasis as an alternative to a tibiotalocalcaneal arthrodesis. Young and active patients who experience refractory pain and stiffness to the rearfoot and ankle secondary to combined severe subtalar and ankle arthrosis are suitable candidates for this surgical procedure. This new approach is based on sound principles in the treatment of severe arthrosis affecting the ankle and subtalar joint. The authors are currently prospectively reviewing their surgical experience with this procedure and believe that it provides an alternative option for the patient, with potentially promising long-term results.

Management of the varus arthritic ankle

Treatment of the arthritic varus ankle presents a significant surgical challenge. The recognition of the causes and associated deformities directs the treatment of the individual patient and optimizes functional outcome. Arthrodesis and total ankle replacement often will need to be augmented by corrective hind- and midfoot procedures and by careful soft tissue balancing. Often multiple procedures are required to achieve the desired result, and patients need to be advised that surgery may need to be staged.

An approach to the failed ankle arthrodesis

Ankle arthrodesis remains the gold standard of surgical treatment for advanced ankle joint arthritis. Failure can occur as a result of infection, nonunion or malunion, resulting in pain and poor function. This paper offers a systematic approach to preventing, and managing these problems should they occur. Revision arthrodesis performed with a detailed understanding of the appropriate alignment and mechanics of the ankle joint, combined with meticulous attention to understanding and reversing the cause of the failure can result in successful salvage and restoration of function.

Ankle arthrodesis: the simple and the complex

Ankle arthrodesis is by no means a simple surgery. It requires preoperative planning, meticulous preparation of bony surfaces, cognizance of ankle positioning, and rigidity of fixation. The procedure also requires enough experience on the part of the operating surgeon to recognize important patient factors and to determine which type of ankle arthrodesis is most appropriate for that specific patient.

Comparison of health-related quality of life between patients with end-stage ankle and hip arthrosis

BACKGROUND

End-stage ankle arthrosis is one of the leading causes of chronic disability in North America. Information on this condition is limited. The amount of pain and the reduction in health-related quality of life and function have not been quantified with use of universal outcome measures. The purpose of the present study was to compare the extent of pain, loss of function, and health-related quality of life in two cohorts of patients waiting for the surgical treatment of end-stage ankle or hip arthrosis.

METHODS

One hundred and thirty patients with end-stage ankle arthrosis who were awaiting total ankle arthroplasty or ankle arthrodesis were recruited through a Canadian Orthopaedic Foot and Ankle Society multicenter study. All patients prospectively completed the Short Form-36 (SF-36) generic outcome instrument. This cohort was compared with a similar cohort of 130 patients with end-stage hip arthrosis, randomly selected from an existing prospective joint replacement database, who had completed an SF-36 questionnaire prospectively from 2000 to 2005.

RESULTS

In both groups, the scores for all SF-36 subscales were approximately two standard deviations below normal population scores. Patients with ankle arthrosis had significantly worse mental component summary scores (p < 0.05), role-physical scores (p < 0.05), and general health scores (p < 0.05). Patients with hip arthrosis reported significantly lower physical function scores (p < 0.05), although the SF-36 physical component summary score was not significantly different between the two groups. The SF-36 physical component summary, bodily pain, vitality, role-emotional, social functioning, and mental health subscale scores were equally affected in both cohorts.

CONCLUSIONS

The mental and physical disability associated with end-stage ankle arthrosis is at least as severe as that associated with end-stage hip arthrosis.

Biomechanics of the ankle joint and clinical outcomes of total ankle replacement

Until the 1970s ankle arthrodesis was considered to be the "gold-standard" to treat arthritis. But the low fusion rate of ankle arthrodeses along with the inability to achieve normal range of motion led to the growing interest in the development of total ankle replacements. Though the short-term outcomes were good, their long-term outcomes were not as promising. To date, most models do not exactly mimic the anatomical functionality of a natural ankle joint. Therefore, research is being conducted worldwide to either enhance the existing models or develop new models while understanding the intricacies of the joint more precisely. This paper reviews the anatomical and biomechanical aspects of the ankle joint. Also, the evolution and comparison of clinical outcomes of various total ankle replacements are presented.

A brief history of total ankle replacement and a review of the current status

Total ankle replacement (TAR) was first attempted in the early 1970s, but poor early results lead to it being abandoned in favour of arthrodesis. Arthrodesis is not totally satisfactory, often causing further hindfoot arthritis and this has lead to a resurgence of interest in joint replacement. New designs which more closely approximated the natural anatomy of the ankle and associated biomechanics have produced more encouraging results and led to renewed interest in total ankle replacement. Three prostheses dominate the market: Agility, Buechel-Pappas and STAR, and improving clinical results with these devices have led to more designs appearing on the market. Modern designs of prosthetic ankles almost exclusively consist of three part prostheses with a mobile bearing component, similar to the Buechel-Pappas and STAR. Clinical results of these newer designs are limited and short-term and have often been carried out by the designers of the implants. This paper presents a brief history of the development of total ankle replacement and a review of the current status.

Gait analysis in ankle osteoarthritis and total ankle replacement

BACKGROUND

Little information is available about gait changes in ankle osteoarthritis and total ankle replacement, and also about total ankle replacement patients' rehabilitation in the first year after surgery.

METHODS

Thirty subjects were included in this study: 15 unilateral post-traumatic ankle osteoarthritis patients and 15 age-/gender-matched control subjects. Patients were followed prospectively: preoperatively, at 3, 6, 9, and 12 months after total ankle replacement. The clinical-functional level was assessed by the American Orthopaedic Foot and Ankle Society ankle and the Short-Form-36 health survey score. 3D ankle-hindfoot kinematic-kinetic analysis was performed using a motion analysis and a two-plate force-platform system. Statistics included repeated measures analysis of variances, independent sample and paired Student's t-tests (significance alpha=0.05).

FINDINGS

Compared to normal subjects, ankle osteoarthritis caused significant reduction of the American Orthopaedic Foot and Ankle Society and Short-Form-36 score. In gait analysis, ankle osteoarthritis showed a significant deficiency in six of seven spatiotemporal variables, a decrease of the tri-planar ankle movement, a decrease of the second active maximal vertical and the maximal medial ground reaction force, a reduction of the sagittal and transverse ankle joint moments, a reduction of the ankle joint power. Three months after total ankle replacement surgery patients experienced a worsening of gait. At 12 months follow-up, all spatiotemporal variables were not different from the normal subjects (full rehabilitation); in six of 11 kinematic and kinetic variables there was a partial rehabilitation.

INTERPRETATION

This study provides data for the clinical-biomechanical understanding of the normal, arthritic, and total ankle replacement treated ankle during walking and the first year of rehabilitation.

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.

Supramalleolar lateral closing wedge osteotomy for the treatment of varus ankle arthrosis

BACKGROUND

Medial ankle joint pain with localized cartilage degeneration due to medial joint overload in varus malalignment of the hindfoot lends itself to treatment by lateral closing wedge supramalleolar osteotomy.

METHODS

From 1998 to 2003, nine patients between the ages of 21 to 59 years were operated. The etiology of the malalignment and degeneration was posttraumatic in eight and childhood osteomyelitis in one. Preoperative and postoperative standing radiographs were analyzed to determine the correction of the deformity and the grade of degeneration. Function and pain were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. The average followup was 56 (range 15 to 88) months.

RESULTS

The average time to osseous union was 10 +/- 3.31 weeks. There were no operative or postoperative complications. The average AOFAS score improved from 48 +/- 16.0 preoperatively to 74 +/- 11.7 postoperatively (p<0.004). The average pain subscore improved from 16 +/- 8.8 to 30 +/- 7.1 (p<0.008). The average tibial-ankle surface angle improved from 6.9 +/- 3.8 degrees of varus preoperatively to 0.6 +/- 1.9 degrees of valgus postoperatively (p<0.004). In the sagittal plane, the tibial-lateral-surface angle remained unchanged. At the final followup, two patients showed progression of radiographic ankle arthrosis grades. In one patient, it rose from grade 0 to I. In the other patient it advanced from grade II to III, with subsequent ankle arthrodesis required 16 months after the index procedure. Seven patients returned to their previous work.

CONCLUSIONS

Lateral supramalleolar closing wedge osteotomy was an easy and safe procedure, effectively correcting hindfoot malalignment, relieving pain, restoring function, and halting progression of the degeneration in the short-term to mid-term in seven of nine patients.

[Ankle arthrodesis versus ankle replacement: a comparison]

Ankle arthrodesis is performed for the treatment of unstable, arthritic, painful, and deformed ankle joints. A wide variety of surgical options and approaches exist to treat the difficult problem of an ankle arthrodesis. In patients with only minor ankle deformity and minor bone loss arthroscopically assisted fusion is the treatment of choice. The risk for the development of a pseudarthrosis depends on clinical factors like corticoid medication, nicotine, incorrect alignment and improper mobilization. With adequate shoes the patients can remain asymptomatic for long time. Adjacent joints may show radiological degenerative changes in the long-term follow-up; however, they do not need to be clinically symptomatic. Nowadays total ankle replacement is a valid alternative. The surgical technique is demanding. Implants of the 1st and 2nd generation did not show satisfying results. The newer 3rd generation total ankle arthroplasties show promising medium-term and long-term results.

Lower leg muscle atrophy in ankle osteoarthritis

The aim of this study was to determine changes in the lower leg muscles associated with ankle osteoarthritis. Fifteen unilateral ankle osteoarthritis patients and fifteen age-gender-matched normal subjects were assessed with clinical [osteoarthritis latency time, pain, alignment, AOFAS ankle score, ankle range of motion (ROM), calf circumference], radiological (ankle osteoarthritis grading), and muscular-physiological parameters [isometric maximal voluntary ankle torque, surface electromyography of the anterior tibial (AT), medial gastrocnemius (MG), soleus (SO), and peroneus longus (PL) muscle]. The osteoarthritis patients had increased pain (6.8 points) and reduced AOFAS score (33.7 points) compared to the control group. Compared to the contralateral healthy leg, the arthritic leg showed reduced mean dorsi-/plantar flexion ROM (16.0 degrees), reduced mean calf circumference (2.1 cm), smaller mean dorsiflexion (16.4 Nm) and plantar flexion (15.8 Nm) torques, lower mean electromyography frequency for all muscles (AT -22.6 Hz; MG -27.3 Hz; SO -25.9 Hz; PL -28.5 Hz), and lower mean electromyography intensity in the AT [-28.0x10(3) (microv)2], MG [-13.3x10(3) (microv)2], and PL [-12.8x10(3) (microv)2]. SO mean electromyography intensity was not significantly changed [+2.0x10(3) (microv)2]. Unilateral ankle osteoarthritis is associated with atrophic changes of the lower leg muscles. This study supports previous observations on muscle dysfunction in knee osteoarthritis.

Preoperative gait characterization of patients with ankle arthrosis

The purpose of this study was to evaluate the kinematic changes that occur about the foot and ankle during gait in patients with degenerative joint disease (DJD). By comparing a normal adult population with what was found in the DJD population we determined how the motion of theses groups differed, thereby characterizing how this pathology affects foot and ankle motion. A 15-camera Vicon Motion Analysis System was used in conjunction with weight bearing radiographs to obtain three-dimensional motion of the foot and ankle during ambulation. The study was comprised of 34 patients and 35 ankles diagnosed with DJD (19 men and 15 women) of the ankle and 25 patients with normal ankles (13 men and 12 women). Dynamic foot and ankle motion was analyzed using the four-segment Milwaukee Foot Model (MFM). The data from this model resulted in three-dimensional (3D) kinematic parameters in the sagittal, coronal, and transverse planes as well as spatial-temporal parameters. Patient health status was evaluated using the SF-36 Health Survey and American Orthopaedics Foot and Ankle Society (AOFAS) hindfoot scores. The DJD group showed significant differences (p<0.001) as compared to normals with prolonged stance time, shortened stride length, reduced cadence and a walking speed which was only 66.96% of normal. Overall, kinematic data in the DJD cohort showed significant differences (p<0.001) in all planes of motion for tibial, hindfoot and forefoot motion as compared to normals. The average preoperative AOFAS hindfoot score was 26. DJD of the ankle results in decreased range of motion during gait. This decreased range of motion may be related to several factors including bony deformity, muscle weakness, and attempts to decrease the pain associated with weight bearing. To date there has not been a study which describes the effect of this disease process on motion of the foot and ankle. These findings may prove to be useful in the pre-operative assessment of these patients.

Outcomes after standardized screw fixation technique of ankle arthrodesis

Several methods of obtaining ankle fusion have been described, with numerous studies reporting on patient populations with varied diagnoses and various methods of fixation. This has led to outcome analyses that are difficult to interpret. Our hypothesis is that using a standard method of fusion, without the aid of allograft, a solid ankle fusion can be achieved in patients with end-stage ankle arthritis, and that this outcome can be reflected in standardized outcome tools. Forty-one consecutive ankle fusions in 40 patients were included in our study, with a minimum followup of 3 years. All patients had an ankle arthrodesis using two parallel retrograde 7.3-mm screws and local fibular graft. All but two patients obtained a solid talocrural union (95%), with a mean postoperative improvement in the American Orthopaedic Foot and Ankle Society score of 23 points. Results of our study showed that a simple technique based on sound mechanical and biologic principles can yield excellent outcomes for patients.

Effects of Ankle-Foot Orthoses on Ankle and Foot Kinematics in Patient With Ankle Osteoarthritis

OBJECTIVE

To determine if different foot orthoses have a similar effect on foot kinematics in subjects with ankle osteoarthritis (OA) when walking on various ground conditions.

DESIGN

Within-subject comparisons study.

SETTING

Biomechanics research laboratory.

PARTICIPANTS

Thirteen subjects with unilateral ankle OA.

INTERVENTIONS

Custom-made ankle-foot orthosis (AFO), rigid hindfoot orthosis (HFO-R), and articulated hindfoot orthosis (HFO-A) were used by subjects when walking on level, ascending and descending ramp, and side-slope conditions.

MAIN OUTCOME MEASURES

The range of motion of the hindfoot (calcaneus relative to tibia) and forefoot (metatarsal relative to calcaneus) was measured using an 8-camera motion analysis system.

RESULTS

The AFO and HFO-R provided the best sagittal plane hindfoot motion restriction over all ground conditions (P<.001). The HFO-R allowed the greatest sagittal plane forefoot motion when walking over level (P=.01) and side-slope (P<.02) conditions, the greatest frontal plane forefoot motion walking down the ramp (P=.003), and the greatest transverse plane forefoot motion when walking over level (P=.011) and ramp-ascending conditions (P=.005). The HFO-A restricted motion of the unaffected joint and did not effectively restrict hindfoot motion.

CONCLUSIONS

The HFO-R not only provides selective restriction to the ankle-hindfoot motion, but also allows sufficient forefoot motion compared with the AFO. We consider the HFO-R to be the best option of all tested orthoses for treating patients with ankle OA pain arising from ankle motion.