Subtalar Joint Subluxation Research Articles

Ankle Radiographic Characteristics of Two Different Types of Valgus Ankle Arthritis: With or Without Progressive Collapsing Foot Deformity

Category: Ankle Arthritis; Ankle Introduction/Purpose: Establishing a surgical plan for ankle arthritis requires a thorough understanding of the deforming forces involved. While ankle morphology-based classification and application are common in the surgical treatment of varus ankle arthritis (i.e., Takakura stage), such an approach has not been described for valgus ankle arthritis. Progressive collapsing foot deformity (PCFD) has been identified as the major cause of non-traumatic valgus ankle arthritis. However, mounting evidence suggests that it can also develop without PCFD, which may mean that the etiology and possibly the outcomes of treatment are different when comparing the two groups. Therefore, this study aimed to investigate whether weightbearing ankle radiographs can be used to differentiate PCFD origin from non-PCFD origin in valgus ankle arthritis. Methods: This study retrospectively reviewed patients who were surgically treated for asymmetric valgus ankle arthritis at our institution between 2017 and 2021. Patients with valgus tibiotalar tilt (TT >4 degrees and Meary’s angle>30 degrees) were included in the PCFD group (n=24). A control group (non-PCFD group [n=24]) with valgus tibiotalar tilt>4 degrees and Meary’s angle < 4 degrees was also established. In the weightbearing ankle anteroposterior (AP) view, the TT and medial distal tibial angle (MDTA) were measured. Additionally, to assess mediolateral position of the talus, the talar center migration (TCM) and lateral talar dome-plafond distance (LTD-P) ratio was measured (Figure 1A). Other PCFD radiographic parameters were also measured. In weightbearing computed tomography (WBCT), the degree of axial plane talocalcaneal subluxation was assessed using transmalleolar axis method as previously described, and the prevalence of sinus tarsi bony impingement was assessed. All parameters were compared between groups using Student t- or chi-square tests. Results: Both groups demonstrated a similar degree of TT, with a mean and standard deviation of 11.1±7.8 degrees in the PCFD group and 12.7±5.9 degrees in the non-PCFD group (p=0.2013, Table 1). However, the PCFD group showed a significantly greater TCM and LTD-P ratio compared to those of the non-PCFD group (p < 0.0001), indicating that PCFD patients have a more medially translated talus in ankle AP radiographs (Figure 1A). WBCT showed that the PCFD group had a greater axial plane talocalcaneal subluxation (p < 0.0001) and a higher prevalence of sinus tarsi bony impingement (p=0.0077) compared to the non- PCFD group, indicating a different degree of subtalar joint subluxation between the two groups. Conclusion: This study demonstrates that weightbearing ankle radiographs reveal different morphologies based on the etiology of valgus ankle arthritis. While both groups exhibited similar degrees of valgus tibiotalar tilt, PCFD patients demonstrated medial translation of the talus compared to non-PCFD patients. We propose a morphology-based classification (Figure 1B) that may assist in differentiating between the PCFD and non-PCFD origins of valgus ankle arthritis. Also, the different morphology of the valgus tibiotalar tilt in the each group may mean that they may require different treatments, as well as potentially different outcomes of treatment for the valgus tibiotalar tilt.

Coronal Shearing Fracture of the Talar Body with Talar Head Dislocation Related to a Navicular Compression Fracture: A Rare Case Report.

A talar body fracture is typically associated with talar body dislocation, resulting in ankle and subtalar joint subluxation and/or dislocation. A talar body fracture with talar head dislocation is a very rare injury. In this report, we describe the case of a 23-year-old man who suffered a coronal shearing fracture of the talar body with talar head dislocation related to a navicular compression fracture. The patient sought orthopedic consultation 6 weeks after injury. The injury was managed with open reduction, talar head relocation, internal fixation of the talar body fracture with Kirschner wires and cancellous screws and talonavicular fusion with an iliac bone autograft. Follow-up 4 years after operative treatment showed that the patient had satisfactory treatment results, including good bone healing with minimal changes in the anterior talotibial compartment and excellent function of the hindfoot and ankle.

Combined weightbearing CT and MRI assessment of flexible progressive collapsing foot deformity

BackgroundThe objective of this study was to evaluate the correlation between Weightbearing CT (WBCT) markers of pronounced peritalar subluxation (PTS) and MRI findings of soft tissue insufficiency in patients with flexible Progressive Collapsing Foot Deformity (PCFD). We hypothesized that significant correlation would be found. MethodsRetrospective comparative study with 54 flexible PCFD patients. WBCT and MRI variables deformity severity were evaluated, including markers of pronounced PTS, as well as soft tissue degeneration. A multiple regression analysis and partition prediction models were used to evaluate the relationship between bone alignment and soft tissue injury. P-values of less than .05 were considered significant. ResultsDegeneration of the posterior tibial tendon was significantly associated with sinus tarsi impingement (p = .04). Spring ligament degeneration correlated to subtalar joint subluxation (p = .04). Talocalcaneal interosseous ligament involvement was the only one to significantly correlate to the presence of subfibular impingement (p = .02). ConclusionOur results demonstrated that WBCT markers of pronounced deformity and PTS were significantly correlated to MRI involvement of the PTT and other important restraints such as the spring and talocalcaneal interosseus ligaments.LEVEL OF EVIDENCE: Level III, Retrospective comparative study.

The Influence of Preoperative Deformity Severity in Postoperative Patient Reported Outcomes in Adult Acquired Flatfoot

Category:Ankle; Hindfoot; OtherIntroduction/Purpose:Adult acquired flatfoot deformity (AAFD) is a complex deformity. Previous work has demonstrated correlation between postoperative foot alignment and patient-reported outcomes. While this work has provided essential targets for surgeons performing flatfoot reconstruction, there is an absence of data that would enable surgeons to predict which patients are likely to have greater or less improvement after surgery based on their preoperative deformity. Conventional radiographs alone may not provide enough detail to isolate individual elements of the deformity. Weightbearing CT (WBCT) allows for far more precise analysis in this regard. We hypothesized that there would be a set of parameters defining preoperative alignment on WBCT that would predict which patients are at risk for a lower magnitude of postoperative improvement in patient-reported outcomes (PROs).Methods:In this retrospective IRB-approved study, patients that underwent surgical flatfoot reconstruction after having a preoperative standing WBCT were identified. Preoperative WBCT images were evaluated by two independent/blinded observers. Multiple parameters related to preoperative alignment and AAFD severity were measured in the sagittal, coronal and transverse planes. Parameters measured included talus-first metatarsal angle; distances between the floor and the navicular, medial cuneiform and cuboid; subtalar joint horizontal angle; superior talar - inferior talar angle; subtalar joint subluxation; talonavicular uncoverage angle; hindfoot moment arm (HMA); and foot and ankle offset (FAO). Prospectively collected data regarding preoperative and postoperative PROs was evaluated. Six PROs components were assessed: physical function; pain interference, pain intensity, global mental health, global physical health and depression. Multivariate regression analysis and a partition prediction model were used to assess the correlation between preoperative alignment and improvement in PROs. P-values of less than 0.05 were considered significant.Results:A total of 51 patients with a preoperative WBCT and postoperative PROs scores were identified and included. Demographic data is shown in Table 1. Multivariate regression analysis demonstrated that preoperative alignment significantly correlated with improvement in three out six components of PROs: pain interference, pain intensity and global mental health. The strongest predictor of improvement in PROMIS physical function t-score was medial cuneiform to floor distance, for pain interference t-score: cuboid to floor distance, for pain intensity: subtalar joint subluxation, for depression t-score: superior talar - inferior talar angle, and for global physical and mental health t-scores: sagittal talus-first metatarsal angle.Conclusion:Our analysis yielded readily identifiable cutoffs for WBCT measurements, where values above or below were correlated with significant differences in the magnitude of PRO score change. Interestingly, measures of sagittal plane collapse and hindfoot valgus were the most predictive of score changes. This data provides useful information for surgeons counseling patients prior to flatfoot reconstruction. Future work using this data to develop prediction models for postoperative outcomes would be valuable, as would studies using WBCT to evaluate the relationship between postoperative corrected alignment and PROs.Complete results are shown in the attached Table.

Left Foot Injury In A Female Gymnast

HISTORY: A 17-year-old female high level gymnast presented for evaluation of left heel pain and ecchymosis. Two days prior to her presentation, she was sprinting in preparation for a roundoff prior to vault take-off and felt her heel shift when she went to push-off. She fell and was immediately unable to bear weight secondary to heel pain. Pain was exacerbated by any weight-bearing activity and improved with rest. She had been wearing a walking boot and using crutches for ambulation. PHYSICAL EXAMINATION: Healthy-appearing female with a muscular build in no apparent distress. Antalgic gait favoring left foot, avoiding pressure on heel. Ecchymosis along both the medial and lateral aspects of the calcaneus. Tenderness to palpation and associated swelling at the plantar aspect of the calcaneus and along the subtalar joint. Ankle range of motion was full and pain-free. Pain with resisted eversion. Talar tilt and calcaneal squeeze tests were positive. No pain with plantar fascia stretching or palpation along the mid to distal plantar fascia. Achilles tendon was intact. Anterior drawer was negative. Strength was full and light touch sensation was intact. DIFFERENTIAL DIAGNOSIS: 1. Calcaneal stress fracture 2. Subtalar joint subluxation 3. Plantar fascia tear TEST AND RESULTS: Left ankle and foot radiographs were negative for acute fracture or dislocation. Left ankle MRI revealed a focal tear involving the lateral margin of the lateral cord of the plantar aponeurosis. FINAL WORKING DIAGNOSIS: Lateral cord plantar fascia rupture TREATMENT AND OUTCOMES: 1. Walking boot for 6 weeks with gradual wean out of boot during the 6th week and ankle range of motion exercises when out of the boot. 2. Once out of boot, supportive shoes with ankle brace and dorsiflexion night splint at night. 3. Physical therapy focusing on Achilles stretching, ankle range of motion and strengthening until pain and tenderness resolved. Slowly advanced to more sports-specific tasks once pain-free. 4. At 10 weeks post injury, she was pain free while performing plyometric and balance/proprioceptive exercises and had a normal exam with full pain-free range of motion. 5. Functional return to sport given her normal exam and pain-free activity with physical therapy.

Assessment of Posterior and Middle Facet Subluxation of the Subtalar Joint in Progressive Flatfoot Deformity.

Adult acquired flatfoot deformity (AAFD) is a complex 3-dimensional pathology characterized by peritalar subluxation (PTS) of the hindfoot. For many years, PTS was measured at the posterior facet of the subtalar joint. More recently, subluxation of the middle facet has been proposed as a more accurate and reliable marker of symptomatic AAFD, enabling earlier detection. The objective of this study was to compare the amount of subluxation between the medial and posterior facets in patients with AAFD. In this institutional review board-approved retrospective comparative study, a total of 76 patients with AAFD (87 feet) who underwent standing weightbearing computed tomography (WBCT) as a standard baseline assessment of their foot deformity were analyzed. Two blinded fellowship-trained orthopedic foot and ankle surgeons with >10 years of experience measured subtalar joint subluxation (as a percentage of joint uncoverage) at the both posterior and middle facets. One of the readers also measured the foot and ankle offset (FAO). PTS measurements were performed at the sagittal midpoint of the articular facets using coronal plane WBCT images. Intra- and interobserver agreement was measured for PTS measurements using the intraclass correlation coefficient (ICC). The intermethod agreement between the posterior and middle facet subluxation was assessed using Spearman's correlation and bivariate analysis. Paired comparison of the measurements was performed using the Wilcoxon test. A multivariate analysis and a partition prediction model were used to assess influence of PTS measurements on FAO values. P values of <.05 were considered significant. ICCs for intra- and interobserver reliabilities were 0.97 and 0.93, respectively, for posterior and 0.99 and 0.97, respectively, for middle facet subluxation. The intermethod Spearman's correlation between subluxation of the posterior and middle facets was measured at 0.61. In a bivariate analysis, both measurements were found to be significantly and linearly correlated (P < .0001; R2 = 0.42). Measurements of middle facet subluxation were found to be significantly higher than those for posterior facet subluxation, with a median difference (using the Hodges-Lehman factor) of 17.7% (P < .001; 95% CI, 10.9%-23.6%). We also found that for every 1% increase in posterior facet subluxation there was a corresponding 1.6-fold increase in middle facet subluxation. Only middle facet subluxation measurements were found to significantly influence FAO calculations (P = .003). The partition prediction model demonstrated that a middle facet subluxation value of 43.8% represented an important threshold for increased FAO. This study is the first to compare WBCT measurements of subtalar joint subluxation at the posterior and middle facets as markers of PTS in patients with AAFD. We found a positive linear correlation between the measurements, with subluxation of the middle facet being significantly more pronounced than that of the posterior facet by an average of almost 18%. This suggests that middle facet subluxation may provide an earlier and more pronounced marker of progressive PTS in patients with AAFD. Level III, retrospective comparative cohort study.

Weightbearing CT and MRI findings of Stage II Flatfoot Deformity: Can We Predict Patients at High- Risk for Foot Collapse?

Category:HindfootIntroduction/Purpose:Adult acquired flatfoot deformity (AAFD) is characterized by concurrent bony deformities, tendinous and ligamentous insufficiencies. Weightbearing CT (WBCT) allows excellent dynamic evaluation of the relative three-dimensional positioning of the tarsal bones. MRI provides accurate evaluation of soft tissue integrity in the unloaded foot. Study’s objective was to evaluate the correlation between bone deformity and soft tissue insufficiency in patients with stage II AAFD, using WBCT and MR images. We hypothesized that significant correlation would be found between WBCT measurements of increased longitudinal arch collapse, hindfoot valgus, peritalar subluxation and forefoot abduction, with MRI findings demonstrating degree of soft tissue involvement.Methods:This retrospective comparative study included 55 patients (56 feet) with stage II AAFD, 20 men and 35 women, mean age of 52.5 (range, 20 to 78) years. Multiple WBCT and MRI variables related to the severity of the deformity were evaluated by four blinded and independent readers (two radiologists and two foot and ankle surgeons), including: arch collapse (navicular-floor distance and forefoot arch angle), hindfoot alignment angle (HAA), forefoot abduction (talonavicular uncoverage angle), subtalar joint subluxation, sinus tarsi and subfibular impingement, and soft tissue insufficiency (posterior tibial tendon, spring and talocalcaneal ligaments). Tendinous and ligamentous involvement on MRI were graded from zero (normal) to four (complete tear). Intra- and interobserver reliabilities were assessed by Pearson/Spearman’s and intraclass correlation coefficient, respectively. A multiple regression analysis was used to evaluate the relationship between bone alignment (WBCT variables) and soft tissue injury (MRI variables). P-values of less than 0.05 were considered significant.Results:We found overall good to excellent intra (range, 0.83-0.99) and interobserver reliability (range, 0.71-0.97) for WBCT measurements and MRI readings. Spring ligament superomedial component involvement was the only finding to correlate with medial column collapse and decreased navicular-floor distance (p=0.03). Superomedial spring ligament and PTT degeneration were also significantly correlated with increased HAA (p<0.01). Involvement of the talocalcaneal interosseous ligament significantly correlated with increased forefoot abduction as measured by the talonavicular uncoverage angle. Spring ligament degeneration, of both superomedial and inferior components, and talocalcaneal interosseous ligaments significantly correlated to subtalar joint subluxation (p<0.001). Involvement of the talocalcaneal interosseous ligament was the only one to significantly correlate to the presence of subfibular impingement (p=0.02). Degeneration of the PTT was significantly associated with sinus tarsi impingement (p=0.04).Conclusion:This study is the first to evaluate correlation between bone, tendinous and ligamentous involvement in AAFD patients, using WBCT and MR images. Our results demonstrated that progressive bone deformity in WBCT is significantly correlated to MRI involvement of the PTT and other important restraints such as the spring and talocalcaneal ligaments. The implications are that WBCT can predict ligamentous injuries and that MRI can predict dynamic bone deformity in AAFD patients. Furthermore, the correlation of bone and soft tissue involvement could impact surgical planning of flatfoot patients, decreasing thresholds for additional soft tissue procedures such as a spring ligament reconstruction.

Weightbearing CT and MRI findings of Stage II Flatfoot Deformity

Category: Hindfoot Introduction/Purpose: Adult acquired flatfoot deformity (AAFD) is characterized by concurrent bony deformities, tendinous and ligamentous insufficiencies. Weightbearing CT (WBCT) is a new imaging technique that allows excellent evaluation of the relative three-dimensional positioning of the tarsal bones in dynamic deformities such as AAFD. MRI, on the other hand, provides an accurate evaluation of soft tissue integrity in the unloaded foot. The objective of this study was to evaluate the correlation between bone deformity and soft tissue insufficiency in patients with stage II AAFD, using WBCT and MR images. We hypothesized that a significant correlation would be found between WBCT measurements of increased longitudinal arch collapse, hindfoot valgus, peritalar subluxation and forefoot abduction, with MRI findings demonstrating degree of involvement of ligaments and posterior tibial tendon (PTT). Methods: This retrospective comparative study included 55 patients (56 feet) with stage II AAFD, 20 men and 35 women, mean age of 52.5 (range, 20 to 78) years. Multiple WBCT and MRI variables related to the severity of the deformity were evaluated by four blinded and independent readers (two radiologists and two foot and ankle surgeons), including: arch collapse (navicular-floor distance and forefoot arch angle), hindfoot alignment angle (HAA), forefoot abduction (talonavicular uncoverage angle), subtalar joint subluxation, sinus tarsi and subfibular impingement, and soft tissue insufficiency (posterior tibial tendon, spring and talocalcaneal ligaments). Tendinous and ligamentous involvement on MRI were graded from zero (normal) to four (complete tear). Intra- and interobserver reliabilities were assessed by Pearson/Spearman’s and intraclass correlation coefficient, respectively. A multiple regression analysis was used to evaluate the relationship between bone alignment (WBCT variables) and soft tissue injury (MRI variables). P-values of less than 0.05 were considered significant. Results: We found overall good to excellent intra (range, 0.83-0.99) and interobserver reliability (range, 0.71-0.97) for WBCT measurements and MRI readings. Spring ligament superomedial component involvement was the only finding to correlate with medial column collapse and decreased navicular-floor distance (p=0.03). Superomedial spring ligament and PTT degeneration were also significantly correlated with increased HAA (p&lt;0.01). Involvement of the talocalcaneal interosseous ligament significantly correlated with increased forefoot abduction as measured by the talonavicular uncoverage angle. Spring ligament degeneration, of both superomedial and inferior components, and talocalcaneal interosseous ligaments significantly correlated to subtalar joint subluxation (p&lt;0.001). Involvement of the talocalcaneal interosseous ligament was the only one to significantly correlate to the presence of subfibular impingement (p=0.02). Degeneration of the PTT was significantly associated with sinus tarsi impingement (p=0.04). Conclusion: This study is the first to evaluate correlation between bone, tendinous and ligamentous involvement in AAFD patients, using WBCT and MR images. Our results demonstrated that progressive bone deformity in WBCT is significantly correlated to MRI involvement of the PTT and other important restraints such as the spring and talocalcaneal ligaments. The implications are that WBCT can predict ligamentous injuries and that MRI can predict dynamic bone deformity in AAFD patients. Furthermore, the correlation of bone and soft tissue involvement could impact surgical planning of flatfoot patients, decreasing thresholds for additional soft tissue procedures such as a spring ligament reconstruction.

Influence of tibialis posterior muscle activation on foot anatomy under axial loading: A biomechanical CT human cadaveric study.

Collapse of the medial longitudinal arch and subluxation of the subtalar joint are common occurrences in adult flatfoot deformity. Controversy exists about the role of the tibialis posterior (TP) tendon as first and/or essential lesion. Subtle changes in the foot configuration can occur under weight bearing. This human cadaveric study is designed to investigate the effect that isolated actuation of the TP tendon has on the medial longitudinal arch and the hindfoot configuration under simulated weight bearing. A radiolucent frame was developed to apply axial loading on cadaveric lower legs during computer tomography (CT) examinations. Eight pairs of fresh-frozen specimens were imaged in neutral position under foot-flat loading (75N) and under single-leg stance weight bearing (700N) without and with addition of 150N pulling force on the TP tendon. Measurements of subtalar joint subluxation, forefoot arch angle and talo-first metatarsal angle were conducted on each set of CT scans. Subtalar subluxation, talo-first metatarsal angle and talo-navicular coverage angle significantly increased under single-leg stance weight bearing, whereas forefoot arch angle significantly decreased. Actuation of the TP tendon under weight bearing did not restore the forefoot arch angle or correct subtalar subluxation and talo-metatarsal angle. Significant effect that weight bearing has on the medial longitudinal arch and the subtalar joint configuration is demonstrated in an ex-vivo model. In absence of other medial column derangement, actuation of the TP tendon alone does not seem to reconstitute the integrity of the medial longitudinal arch or correct the hindfoot subluxation under weight bearing. The findings of this study together with the developed model for ex-vivo investigation provide a further insight in foot anatomy.

Isolated Fractures of the Sustentaculum Tali: Injury Characteristics and Surgical Technique for Reduction Management

ABSTRACT Isolated fractures of sustentaculum tali are rare and often missed at an initial visit. They can be difficult to manage and may have implications for future hindfoot function. This article describes sustentacular fracture patterns and characteristics, and a method of surgical treatment via a medial approach to the calcaneus. During the last 6 years, 11 recent isolated sustentacular fractures without calcaneal posterior facet involvement were surgically-treated at our hospital. Of these all underwent open reduction and internal fixation via medial approach to the calcaneus. Patient charts, X-ray radiographs and CT scans were reviewed for injury characteristics and associated musculoskeletal injures. Five patients had intra-articular middle facet involvement, and two had subtalar joint subluxation. By cannulated screws reduction was maintained through fractures rigidly fixation. Isolated fracture of the sustentaculum tali is tend to be ignored and easily misdiagnosed as acute ankle sprain. Open reduction and internal fixation of this fractures was reliable and should be procedure via medial approach. How to cite this article mu h, xiangyang x, gang b. Isolated Fractures of the Sustentaculum Tali: Injury Characteristics and Surgical Technique for Reduction Management. J Foot Ankle Surg (Asia-Pacific) 2014;1(2):48-51.

Fractures of the Sustentaculum Tali: Injury Characteristics and Surgical Technique for Reduction

The sustentaculum tali of the calcaneus is a vital load-bearing structure. Isolated sustentacular fractures are rare and may have implications for future hindfoot function. This retrospective cohort study describes sustentacular fracture patterns and characteristics, associated foot injuries, and a method of surgical treatment via a medial approach to the calcaneus. During a 7-year period, 19 surgically-treated sustentacular fractures without calcaneal posterior facet involvement were identified from a prospectively-collected database at a single Level 1 regional trauma center. Of these, 15 underwent open reduction and internal fixation utilizing a medial approach to the calcaneus. Patient charts, plain radiographs, and CT scans were reviewed for injury characteristics/morphology and associated musculoskeletal injuries. Fourteen patients had associated ipsilateral foot/ankle injuries, and nine had other musculoskeletal injuries. Seven patients had intra-articular middle facet involvement, and seven had subtalar joint subluxation or dislocation. The medial approach to the calcaneus involves distal retraction of the neurovascular bundle and toe flexors. This allowed for an accurate indirect articular reduction using the extraarticular medial calcaneal cortex, as well as reduction of any associated subluxations. No complications were related to the surgical approach. Reduction was maintained through fracture healing. Fractures of the sustentaculum tali are rare injuries associated with high energy mechanisms, and associated ipsilateral foot injuries are common. Open reduction and internal fixation of these fractures was reliable and possible through a medial approach involving distal retraction of the digital flexors and neurovascular bundle, allowing for an anatomical extraarticular cortical reduction.

Weightbearing CT Scan of Severe Flexible Pes Planus Deformities

The three-dimensional relationships of the bones in the foot in a flatfoot deformity are difficult to assess with standard radiographs. CT scans demonstrate these relationships but are typically made in a nonweightbearing mode. Our objective was to assess the use of a weightbearing CT apparatus to image the feet in patients with severe flexible pes planus deformities and to better define the anatomical changes that occur. A specialized device was designed and constructed to simulate weightbearing to the feet during CT examination. Eighteen normal feet and 30 painful severe and flexible pes planus feet were imaged in both the non weightbearing and weightbearing states, set at 50% of body weight. Several measurements of intertarsal relationships were made of the pes planus and normal feet. Navicular floor to skin distance, forefoot arch angle, and subtalar joint subluxation were measured in the coronal plane in both the weightbearing and nonweightbearing states. T-tests were used to analyze measurements of navicular floor to skin distance and forefoot arch angle. The weightbearing device had a significant effect on foot configuration for both normal and pes planus feet (p = 0.0008) and (p < 0.0001) respectively for both floor to skin distance and forefoot arch angle. There was a significant difference between normal feet and pes planus feet with regard to the forefoot arch angle in the nonweightbearing (p = 0.02) and weightbearing states (p = 0.01). Four of the pes planus patients had evidence of subtalar joint subluxation which was more pronounced in the weightbearing state. There was no significant difference between the navicular floor to skin distance in the normal versus pes planus feet in either the non weightbearing (p = 0.05) or the weightbearing states (p = 0.07). A device was designed and constructed to apply a weightbearing load equal to that of 50% body weight with minimal to no patient discomfort. The resultant effects on foot configuration were significant, and are useful for assessment of degree of flexible flat foot deformity, thus guiding clinical management. The measure which most significantly differed between pes planus patients and normal volunteers was the forefoot arch angle. Forefoot arch angle may therefore be the most useful measure for the imaging diagnosis of flexible pes planus, and the degree of planus deformity.

Pseudo os trigonum sign: missed posteromedial talar facet fracture.

Posteromedial talar facet fracture (PMTFF) is a rare injury, sparsely reported in the literature. This article proposes that PMTFF is often left undiagnosed by orthopaedic surgeons and suggests the routine application of advanced radiographic studies (i.e., CT scan) in the recognition of PMTFF. It also evaluates nonoperative management of PMTFF. After obtaining Institutional Review Board approval, the medical records over a 5-year period (1997-2001) were retrospectively reviewed from the foot and ankle service of a level 1 trauma center, identifying all cases of PMTFF. Charts were reviewed for relevant data. Results of treatment were assessed during follow-up physical examination. Six cases of PMTFF were identified over a 5-year period. All injuries were associated with medial subtalar joint dislocation. Four of six (66%) patients were not initially diagnosed with PMTFF, but instead misdiagnosed as an os trigonum. The remaining two patients had an established diagnosis of PMTFF at the time of initial treatment. All had short leg cast immobilization for medial subtalar dislocation. CT evaluation yielded additional diagnoses in all six patients. All six patients showed a PMTFF. Five patients (83%) revealed persistent subtalar joint subluxation. Five of six (83%) patients required at least one additional procedure as a result of an undiagnosed or nonoperatively treated PMTFF. Four patients underwent subtalar joint fusion, and one patient underwent tibiotalar calcaneal fusion secondary to concomitant ankle/subtalar arthritis. The patient who did not undergo recommended fusion continued to be symptomatic. Diagnosis of PMTFF necessitates a heightened clinical suspicion, especially when a medial subtalar joint dislocation is present. Proper imaging studies, such as coronal CT scan, should be performed after any subtalar dislocation. Timely treatment, in the form of open reduction and internal fixation for large fragments involving the articular surface or surgical excision for smaller fragments, is recommended in order to restore proper anatomy and function of the subtalar joint. This study verifies the significant morbidity associated with an undiagnosed or nonoperatively treated PMTFF.

Biomechanical analysis of running with 25 degrees inverted orthotic devices

The purpose of this study was to evaluate the effectiveness of two different rigid foot orthotic devices in controlling subtalar joint subluxation and pronation. A high-speed video analysis system was used to record, store, and analyze data from seven runners: 1) barefoot, 2) shoes only, 3) shoes and vertical orthoses, and 4) shoes with 25 degrees inverted orthotic devices. The results indicate the need for suitable studies, on a larger population group, to evaluate the effect of a variety of orthotic devices on running biomechanics.