Comparative review of surgical treatment of the idiopathic clubfoot by three different procedures at Columbus Children's Hospital

Ninety-nine feet in 54 children were both clinically and roentgenographically evaluated following one of three different procedures of soft tissue clubfoot release. A new rating system that weights dynamic functional results more heavily was used to compare results. Roentgenographic complications included both over- and undercorrection at the talonavicular articulation, avascular necrosis of the talus, navicular, and calcaneus, and talar dome flattening. Recommendations concerning technical aspects of operative approach to clubfeet include (a) more physiologic orientation of the bimalleolar axis, (b) anatomic alignment at the talonavicular joint, and (c) use of the hinged ankle cast brace to increase final ankle range of motion (ROM).     

Assessment of talar flattening in adult idiopathic clubfoot

BACKGROUND: The radius/length (R/L) ratio was developed to evaluate the convexity of the talar dome in idiopathic clubfoot. However, the index has not been tested for its reliability and reproducibility. METHODS: The R/L ratio was determined by three independent observers on the radiographs of 21 adult patients with idiopathic clubfoot and 30 adult subjects with normal feet. The reproducibility and the reliability of the R/L ratio were calculated. RESULTS: For the normal feet the reproducibility and the reliability of the R/L ratio was high (correlation coefficient > 0.87). For the patients with clubfoot, the reliability and reproducibility depended on the severity of talar flattening. For a radius of less than 45 mm the mean intraobserver correlation coefficient was 0.74 (range 0.54 to 0.83) and the mean interobserver correlation coefficient was 0.58 (range 0.49 to 0.75). For a radius of more than 45 mm no statistically significant intraobserver and interobserver correlations were found. CONCLUSION: The current results indicate that the R/L ratio of talar flattening is reliable and reproducible for mild talar deformity but not for severe flattening (radius of more than 45 mm).     

Clinical and radiographic features of operatively treated stiff clubfeet after skeletal maturity: etiology of the deformities and how to prevent them

BACKGROUNDS: Residual deformities of operatively treated severe clubfeet evaluated radiographically have been rarely studied in detail in adults. METHODS: Twenty-five operatively treated stiff clubfeet were analyzed at a mean age of 21 years and 6 months. The clinical evaluation used the Laaveg and Ponseti scale for clubfeet. Radiographic assessment was done with weightbearing and dynamic views. RESULTS: Clinical evaluation was globally good except for motion (poor). Radiographic assessment showed residual abnormalities in all feet. The distal tibial epiphysis showed slanting of its posterior part in seven feet (28%) and notching of its anterior lip in 13 (52%). Talar length, calcaneal length, and talar trochlear height were significantly smaller in clubfeet compared to normal feet. Undercorrection of hindfoot varus, was found in 19 feet (76%) but was well tolerated. Navicular wedging was present in seven (28%), and cavus deformity was found in seven (28%). Dorsal bunion, hallux varus, and skewfoot were found in four (16%), two (8%), and three (12%), respectively. The dynamic views demonstrated a significant decrease in the foot and ankle mobility with compensation mechanisms such as anterior talar incongruence or midfoot hypermobility. CONCLUSION: Severe clubfeet never become normal at adult age either clinically or radiographically. Multiple radiographic deformities exist. Their etiology and possible prevention are discussed. Despite the numerous abnormalities, clinical results were good at skeletal maturity.     

Correlation of foot radiographs with foot function as analyzed by plantar pressure distribution

The goal of this study was to correlate radiographic measurements to the dynamic plantar pressure of the residual clubfoot. This was done by comparing radiographs and EMED plantar pressure results in 61 idiopathic clubfeet in 39 children at an average of 8 years after complete subtalar release. Radiographic measures were obtained using the standard method outlined by Simons, and pressure data were collected for eight regions of the foot. Pearson correlation analysis was performed and the most significant correlation was found between the calcaneal/first metatarsal angle in the lateral radiographic view (r = 0.72) and the midfoot contact area. In the anteroposterior view there was mild correlation between the talus/first metatarsal angle and both the peak pressure and plantar contact area. The results of this study indicate that radiographs used in concert with dynamic plantar pressure analysis will provide a more complete assessment of the corrected clubfoot.     

Dynamic foot-pressure measurement in the assessment of operatively treated clubfeet

BACKGROUND: Decreased motion of the subtalar joint is common after operative treatment of idiopathic clubfeet. The purposes of this study were to validate parameters of dynamic foot-pressure measurement that enable detection of physiological pronation of the subtalar joint and to analyze the consequences of absent or decreased pronation following clubfoot surgery on long-term functional results. METHODS: To validate parameters of dynamic foot-pressure measurement, we initially analyzed two control groups: one of forty asymptomatic normal feet and the other of five feet with a previous subtalar joint arthrodesis. The resulting parameters were then applied to a group of nineteen patients with twenty-four idiopathic clubfeet for whom initial conservative treatment had failed and in whom a posterior surgical release (lengthening of the Achilles tendon and release of the posterior ankle capsule) had been performed at a mean age of twenty months. The mean duration of follow-up was forty-one years. All feet were evaluated radiographically, and the clinical results were assessed with the American Orthopaedic Foot and Ankle Society score. RESULTS: An interruption in the rise of the pressure-time curve and a short medial deviation of the center of pressure path immediately after heel strike are reliable and objective characteristics of pronation movement of the subtalar joint. Nineteen clubfeet had a demonstrable pronation movement, and five clubfeet did not. The nineteen feet with pronation movement were either asymptomatic (twelve feet) or mildly painful on occasion (seven feet). The mean American Orthopaedic Foot and Ankle Society score for the nineteen feet was 87 points. The five feet without pronation movement were moderately painful during strenuous activities only (four feet) or were nearly always painful (one foot). The mean score for those feet was 57 points. There was a significant difference between these two groups with regard to the pain scores and the total scores (p < 0.001), but there was no appreciable difference regarding function and hindfoot motion. It was not possible to distinguish between these two groups on the basis of the findings of the physical or radiographic examinations. CONCLUSIONS: Idiopathic clubfeet with preserved hindfoot pronation have a better long-term prognosis. Preservation of functional mobility of the subtalar joint is a key factor in the treatment of clubfoot deformity.     

Avascular necrosis of the talus after McKay clubfoot release for idiopathic congenital clubfoot

Avascular necrosis of the talus is a serious potential complication of clubfoot surgery. In the few cases described in the literature, the necrosis has involved the entire talus and resulted in progressive fragmentation and collapse. Serial postoperative radiographs of 96 idiopathic clubfeet in 70 patients are reviewed here to determine the incidence of avascular necrosis after McKay soft tissue release. Based on criteria in the literature for making the diagnosis, no cases of avascular necrosis were seen. Growth lines were observed in the cuboids and calcanei of all the feet during the follow-up period. Eight feet failed to develop growth lines in the talus during follow-up. Five of these feet showed flattening of the dome of the talus and three hypoplasia of the talar head and neck at the most recent follow-up. Absence of normal growth lines in the talus after operation seems to predict talar abnormalities.     

Ponseti method compared to previous treatment of clubfoot in Norway. A multicenter study of 205 children followed for 8–11 years

Purpose

Despite few studies comparing Ponseti treatment and traditional treatment of clubfoot (talipes equinovarus), the Ponseti method is now accepted as standard treatment for this deformity. The Ponseti method was introduced in Norway in 2003 and the purpose of this multicenter-study was to compare the results of Ponseti treatment with the results of the previous treatment for clubfoot in Norway.

Methods

90 children (134 clubfeet) treated with previous treatment (pre-Ponseti group), were compared to 115 Ponseti treated children (160 clubfeet) (Ponseti group). The previous treatment consisted of casting and surgery if needed. At 8–11 years of age, all children were examined by the same orthopaedic surgeon, the parents answered a questionnaire, all feet were X-rayed and information about surgical procedures was obtained from the patient records.

Results

The number of surgeries was higher in the pre-Ponseti group, and the number of extensive surgeries was 119 in the pre-Ponseti group compared to 19 in the Ponseti group. The range of motion in the ankle joint was better in the Ponseti group. Children in this group had better function, higher satisfaction and less pain according to patient and parent reported outcome measures. The incidence of moderate or severe talar flattening was higher in the pre-Ponseti group.

Conclusion

Ponseti treatment seems to be superior to the previous treatment in Norway, with regards to number and severity of operations, flexibility of the foot and ankle, parent/patient reported outcome and the presence of talar flattening on X-ray.

     

A new dynamic foot abduction orthosis for clubfoot treatment

Recurrent clubfoot deformity after successful initial correction with the use of the Ponseti method continues to be a common problem and is often caused by noncompliance with wear of the traditional foot abduction brace. The purpose of this study was to assess the results of a newly designed dynamic foot abduction orthosis in terms of (1) parental compliance and (2) effectiveness in preventing recurrent clubfoot deformities. Twenty-eight patients (49 clubfeet) who were treated with a dynamic foot abduction orthosis in accordance with the Ponseti method were included in this study. Of the 28 patients, 18 had idiopathic clubfeet (31 clubfeet), 2 had complex idiopathic clubfeet (4 clubfeet), 5 had myelodysplasia (8 clubfeet), and 3 were syndromic (6 clubfeet). The mean duration of follow-up was 29 months (range, 24-36 months). Noncompliance was reported in only 2 (7.1%) of the 28 patients in the new orthosis compared with the authors' previously reported 41% (21/51) noncompliance rate in patients treated with the use of the traditional foot abduction brace. The two patients in this study, in which parents were noncompliant with orthosis wear, developed recurrent deformities. There were 2 patients (7%) who experienced skin blistering in the new orthosis compared with 12 (23.5%) of 51 patients who experienced blistering with the use of traditional abduction brace in the authors' previously reported study. Logistic regression modeling compliance and recurrence revealed that noncompliance with the foot abduction orthosis was most predictive of recurrence of deformity (odds ratio, 27; 95% confidence interval, 2.2-326; P = 0.01). The articulating foot abduction orthosis is well tolerated by patients and parents and results in a higher compliance rate and a lower complication rate than what were observed with the traditional foot abduction orthosis.     

When does the flat-top talus lesion occur in idiopathic clubfoot: evaluation with magnetic resonance imaging at three months of age.

Flat-top talus has been described as a pathologic change secondary to idiopathic clubfoot condition and/or as a direct result of nonoperative manipulation involving forced dorsiflexion and molding of the cartilaginous talus. No definitive study, however, on the etiology and the timing of the flat-top talus deformity has been performed to date. The authors evaluated the magnetic resonance images of eleven patients with idiopathic clubfoot deformities treated with 2 to 3 months of casting to assess if flattening of the talar dome occurred at this age with this amount of casting. All children were 3 months of age, were casted for a maximum of 2 to 3 months, and sedated before MRI examination. The images were evaluated for maximum talar head height, maximum talar body height, and deviation of the talar body from a perfect circle. Maximum talar head height ranged from 4 to 9 mm, maximum talar body height ranged from 6 to 10 mm. Eight of the eleven had maximum talar body measurements 3 to 5mm greater than maximum talar head height. Three of the eleven patients had head and body size of equal proportion. Two of the eleven had a talar body that was within 1 mm of a perfect circle. The remaining nine patients had perfectly round talar bodies. In the senior author's (RSD) experience with treating clubfeet, a substantial increase has been seen at operation in flat-top tali among children that were casted for more than 1 year before surgical correction, compared to children casted for 3 months before surgical correction. The current investigation indicated that although tali of children with clubfeet are abnormally shaped, the talar body remains larger than the talar head and maintains its roundness after two to three months of corrective casting. Maintenance of cast treatment for more than three months may lead to the flat-top talus deformity. The authors recommend surgical intervention following three months of failed manipulation and casting to prevent this deformity.     

Radiographic evaluation of idiopathic clubfeet undergoing Ponseti treatment

BACKGROUND: The Ponseti method for treatment of idiopathic clubfeet involves the use of serial casts, percutaneous Achilles tenotomy in most cases, and bracing with an abduction orthosis to prevent relapse. Although Ponseti recommended evaluation of the infant clubfoot strictly by palpation, many orthopaedic surgeons still rely on radiographs for decision-making during treatment. The aim of this study was to document with radiographs the effect of percutaneous Achilles tenotomy as described by Ponseti. METHODS: We conducted a study of idiopathic clubfeet treated, at two centers, with the Ponseti method, including percutaneous Achilles tenotomy. Cast treatment was started within three weeks after birth, and radiographs were made before and after the tenotomy. Lateral radiographs with the foot in maximal dorsiflexion at the ankle were made for all patients, and anteroposterior radiographs of the foot were made at one center. The lateral tibiocalcaneal angle, the anteroposterior talocalcaneal angle, and the lateral talocalcaneal angle were measured on the radiographs. Foot dorsiflexion at the ankle was evaluated clinically. The results from both centers were evaluated separately and in combination. RESULTS: Lateral dorsiflexion radiographs that showed the foot and ankle were evaluated for eighty-seven clubfeet, and anteroposterior radiographs that showed the foot were evaluated for sixty-five clubfeet. The mean improvement in the lateral tibiocalcaneal angle after the tenotomy was 16.9 degrees . The mean change in the anteroposterior talocalcaneal angle was 2.1 degrees , and the mean change in the lateral talocalcaneal angle change was 1.4 degrees . The mean increase in clinically measured dorsiflexion after the tenotomy (in sixty-five feet) was 15.1 degrees . Only the lateral tibiocalcaneal angle and dorsiflexion as measured clinically changed significantly after the Achilles tenotomy (p < 0.05). When the results at each center were analyzed separately, they were found to be nearly identical. CONCLUSIONS: The increase in the lateral tibiocalcaneal angle after Achilles tenotomy is essentially the same as the increase in ankle dorsiflexion seen on clinical examination. The anteroposterior and lateral talocalcaneal angles are not influenced significantly by the tenotomy. Radiographs confirmed that the additional dorsiflexion obtained from the percutaneous Achilles tenotomy is true dorsiflexion occurring in the ankle and hindfoot and not in the midfoot. LEVEL OF EVIDENCE: Therapeutic Level IV.     

CT Study on the Effect of Different Treatment Protocols for Clubfoot Pathology

In congenital clubfoot, residual deformities are not well-documented and they may change depending on different treatments. To identify the treatment that provides better outcome at maturity, we studied the computed tomography of two cohorts of patients affected with congenital clubfoot who were treated using two distinct protocols. Forty-seven clubfeet were treated according to the traditional protocol of our hospital and 61 were treated according to the Ponseti technique. The normal feet of the unilateral deformities served as controls. All patients were followed to skeletal maturity. The ankle torsion angle and the declination angle of the neck of the talus were higher than normal but different only in patients treated with the traditional method. The calcaneocuboid angle was lower but only in patients treated with the Ponseti method. The shape of the talar joints was altered in many feet regardless of protocol. The CT images suggest the modifications of the torsion angle of the ankle, the declination angle of the neck of the talus, and the calcaneocuboid angle at maturity are related to the treatment protocol followed. The Ponseti manipulative technique provided better anatomical results in comparison to our traditional technique. Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.     

Evaluation of pathologic abnormalities of clubfoot by magnetic resonance imaging

Three-dimensional analyses of clubfoot in infants younger than 1 year of age were done using magnetic resonance imaging in an in vivo study. Twenty-one patients (31 feet) with congenital clubfoot were examined. The average age at examination was 8.6 months (range, 4-12 months). All patients originally were treated using corrective casts. Seventeen feet required complete subtalar release operations and the remaining 14 feet were treated conservatively with various orthoses. Four measurements using magnetic resonance imaging were performed in the transverse and coronal planes as follows: the calcaneus adduction angle, to define the degree of medial rotation of the calcaneus in the transverse plane; the navicular angle, to define the degree of medial displacement of the navicular; the talus neck angle, to define the degree of medial angulation of the talus; and the calcaneus shift index, to define the degree of medial shift of the calcaneus beneath the talar head in the coronal plane. In the results, all four measurements of clubfoot on magnetic resonance imaging were statistically different from those of normal feet. In the surgical group there were statistical differences in the calcaneus adduction angle, the navicular angle, and the calcaneus shift index (including two feet of patients whose parents had rejected proposed treatment), compared with the conservative group, but there was no statistical difference in the talus neck angle. Magnetic resonance imaging could delineate the three-dimensional abnormalities of the tarsal bones in clubfoot and quantitatively evaluate the severity of clubfoot.     

Magnetic resonance imaging of severe idiopathic club foot treated with one-week accelerated Ponseti (OWAP) technique

PurposeThis study aims to evaluate changes in tarsal bones relationship after the use of one week accelerated Ponseti method in the treatment of severe idiopathic clubfoot using MRI. We hypothesize that one-week accelerated Ponseti is at least as effective as standard techniques in achieving the desirable MRI parameters.MethodsThis is a prospective study of 8 children with severe idiopathic clubfeet (Pirani 6) (4 unilateral and 4 bilateral) treated before the age of three months with one-week accelerated Ponseti technique, as described in a former study with minimum 2-year follow-up. The 8 corrected feet were compared with the 4 unilateral normal feet at clinical and radiological levels using a Pirani scoring system and an MRI, respectively.ResultsClinical results showed that Pirani score was 1.1 in the last follow up in comparison to Pirani 6 pretreatment (p < 0.05). MRI results indicated that the malleocalcaneal angle, axial malleocalcaneal index, coronal tibiocalcaneal angle, sagittal talocalcaneal angle, and talar head neck calcaneal rotation showed statistical difference between the two groups (p < 0.05). Sagittal malleocalcaneal index, sagittal tibiocalcaneal angle, talar head neck rotation related to talar body, and posterior calcaneal rotation showed no statistical difference between normal feet and clubfeet after correction (p value >0.05).ConclusionOne-week accelerated Ponseti technique showed to be as effective and safe as other treatment methods through clinical and MRI follow up data. MRI role was to confirm the efficiency of this innovative accelerated technique, but not used as a routine follow up.     

Idiopathic clubfoot: ten year follow-up after a soft tissue release procedure

Purpose

Our objective is to report longitudinal outcomes of selective surgical soft tissue release for idiopathic clubfoot (ICF).

Methods

Thirty-six ICF patients who had surgery at the average age of 11 (range nine to 17) months and 12 age-matched normal feet were evaluated yearly until subjects had the average age of 11 (range seven to 19) years using eight radiographic parameters. The Ponseti and Dimeglio scores were rated. Serial ankle and subtalar motions and talocalcaneal (TC) index changes over time were analyzed using mixed effects random-intercept longitudinal models.

Results

At the last follow-up, ankle and subtalar motions were more restricted in the ICF but no significant changes in motion were observed over follow-up, except for small but significant decreases in the TC index in both ICF and control feet. The average measurement in ICF group versus control revealed significantly lower angles in the five assessed parameters. The mean Ponseti score was 88 (range 40–97) and ICF showed an improvement of the Dimeglio score. A positive correlation between the Ponseti score and the subtalar motion was noted, whereas talar flattening had a negative influence on the ankle motion.

Conclusions

Soft tissue release surgery limited to only pathologies encountered during the procedure maintains motions of ankle and subtalar joints in ICF.

     

V osteotomy and Ilizarov technique for residual idiopathic or neurogenic clubfeet

PURPOSE. To report the treatment outcomes of V osteotomy and Ilizarov technique for residual idiopathic or neurogenic clubfeet. METHODS. 13 patients (14 feet) aged 8 to 18 years underwent V osteotomy via the calcaneus and talus, followed by gradual distraction of soft tissue and bone for foot reconstruction. Eight of the clubfeet were idiopathic and had undergone previous surgeries. The remaining 6 were neurogenic and their pathologies were: Charcot-Marie-Tooth disease (n=2), myelomeningocele (n=2), neurofibromatosis (n=1), and distal arthrogryposis (n=1). Three of them had undergone previous surgeries. The Ilizarov frames were retained for 3 to 6 months and the patients were followed up for 1.8 to 8.9 years. Range of movement of the ankle and foot, appearance and position, gait, pain, function, and patient satisfaction were assessed according to the modified clubfoot grading system. The talo-1st metatarsal angle was measured on anteroposterior radiographs. RESULTS. Scores associated with the appearance and position of the foot, and thus patient satisfaction were significantly improved, but not for range of movement, pain, and function. The mean preoperative and final talo-1st metatarsal angles were 39.7 and 8.7 degrees, respectively (p<0.01). Ten feet achieved the plantigrade position, one had residual equinus, and 3 had residual adduction and supination. CONCLUSION. Patient satisfaction improved significantly despite no major improvement in pain, function, and range of movement of the ankle and foot. This reflects the importance of the appearance and position of the foot, and justifies the decision to undergo this long and demanding procedure.     

关节镜辅助下带骨膜的胫骨移植治疗距骨骨软骨损伤的手术方法及临床疗效

背景:距骨骨软骨损伤常继发于踝关节运动扭伤或踝部骨折,临床上表现为踝关节周围的深部疼痛,负重、跑、跳后疼痛加重,踝关节伸屈活动受限.由于踝关节在运动中承受着巨大的压力,且软骨损伤后的自我修复能力比较受限,距骨软骨损伤后的有效治疗一直都是足踝外科中较为棘手的难题.目的:探讨关节镜辅助下带骨膜的胫骨移植治疗距骨骨软骨损伤的...     

Assessment of the talar deformity and alignment in congenital clubfoot using three-dimensional MRI after Ponseti method

BackgroundPonseti method have been widely accepted as the initial treatment of congenital idiopathic clubfoot because its excellent primary result. On the other hand, relapses after Ponseti method are not uncommon and the cause of relapses have not been fully elucidated. We investigated detailed morphology and alignment of tarsal bones in clubfoot after Ponseti method using three-dimensional MRI analysis.MethodsWe performed MRI with 10 patients of unilateral clubfoot at three months after Achilles tenotomy. Based on the MRI volume data, we reconstructed three-dimensional bone surface model using the marching cubes method. We evaluated the volume of the talus and navicular bone, medial and planter deviation of the talar head and neck, medial deviation of the navicular bone, and internal rotation angle of the distal tibiofibular joint.ResultsIn clubfoot, the volume of talus and navicular bone were significantly smaller compared with the contralateral side. Deviation of the talar head and neck varied from medially to almost the same as that on the contralateral side. The degree of deformity of the talus and alignment of the navicular bone and distal tibiofibular joint showed correlations.ConclusionsPatients with the medial deviated talar neck might have the alignment change of navicular bone and distal tibiofibular joint. Deformity of talar neck might to be compensated by talonavicular joint and distal tibiofibular joint through the manipulation of Ponseti method.     

A novel orthosis for the treatment of clubfoot

We introduce a novel orthosis used with serial manipulations for the treatment of 14 congenital clubfeet (six boys and three girls). The average age at the time of initial treatment was 3.5 months (range, 2-6 months). The average length of treatment was 4.9 months (range, 3-7 months). All patients traveled at least 480 kilometres for their clinic visits. According to the clubfoot classification of Dimeglio et al., 12 clubfeet (85%) were severe and two clubfeet (15%) were moderate. At the end of treatment, all clubfeet were improved by at least one level of grading. Although all clubfeet went on to operative treatment, the initial non-operative treatment did improve the clubfeet. We propose the use of our technique for the non-operative treatment of patients presenting beyond the newborn period with clubfoot, who are restricted in traveling over long distances.     

Deformity and disability from treated clubfoot

To identify disability associated with treated unilateral, idiopathic clubfoot deformity, 29 patients and 23 controls were compared by morphometry, radiography, and performance testing. The average period following definitive treatment was greater than 10 years. Treatment regimens varied from prolonged casting to early posteromedial release. The most significant limitations in these treated clubfeet averaged (a) a 42% decrease in normal ankle motion, specifically lacking 65% of normal dorsiflexion, a consistent finding independent of treatment; (b) a 24% decrease in normal plantarflexor muscle strength, correlating directly to the number of heelcord lengthenings per foot; and (c) a noticeable 10% decrease in calf girth, unrelated to total time spent in cast.     

Assessment of the three-dimensional relationship of the ossific nuclei and cartilaginous anlagen in congenital clubfoot by 3-D MRI.

PURPOSE: Radiographic measurement is the usual method used to objectively determine the extent of a congenital clubfoot deformity. Although radiographs have been used clinically to estimate the size and location of tarsal bones through measurements of the ossific nuclei, it is not clear to what extent these relationships are actually reflected in these measurements. So, we used a 3-D MRI system that could more objectively estimate sizes and positional relationships. MATERIAL AND METHOD: We evaluated 5 patients with unilateral congenital clubfoot deformity. Magnetic resonance imaging was performed of both feet using 1.5-T magnet. Based on the resulting magnetic resonance imaging volume data, a three-dimensional surface bone model was reconstructed by the Marching Cubes method. We used this model to perform a comparative analysis of the volume and volume ratio of each cartilaginous anlage and ossific nucleus, the length of the talus and the calcaneus, and the position of the center of gravity of ossific nuclei within the cartilaginous anlagen. We measured the relationship between the ossific nuclei and cartilaginous anlagen in the talus and calcaneus of patients with unilateral clubfoot deformity. RESULT: In clubfeet talus volume was reduced by 20.1% and calcaneal volume was reduced by 15.7%. Furthermore, the volume of the talar ossific nucleus was reduced by 42.6% and that of the calcaneal ossific nucleus was reduced by 12.1%. The length of the clubfoot talus was 8.2% shorter than normal, and that of the calcaneus was 4.8% shorter. CONCLUSION: The assessment technique presented herein was shown to be useful in ascertaining the various pathological characteristics associated with clubfoot.