High prevalence of tarsal coalitions and tarsal joint variants in a recent cadaver sample and its possible significance

Take a load off: skeletal implications of sedentism in the feet of modern body donors

Background and Objectives

Modern biocultural environments continue to place selective pressures on our skeletons. In the past century, a major cultural pressure has been the rise in sedentism. However, studies considering the effects of sedentism on the foot have largely considered pathological changes to the gross foot without particular regard for the pedal skeleton. To address this gap in the literature, temporal trends in the development of osteoarthritis and entheseal changes on the tarsals and metatarsals were analyzed in the context of biodemographic data for recent modern humans.

Methodology

The sample utilized for this project is comprised of 71 individuals from the William M. Bass Donated Skeletal Collection, with birth years ranging from 1909 to 1993. Temporal trends in osteoarthritis and entheseal changes were determined via ANCOVA, using year of birth as the explanatory variable and biodemographic variables (age, sex, stature, body mass index and tibial robusticity) as covariates.

Results

Results indicate that entheseal changes and osteoarthritis have decreased over time, and these trends are statistically significant. Temporal trends in pedal entheseal changes and osteoarthritis vary by sex.

Conclusions and Implications

The increase in sedentary behavior over time has usually been framed as a net negative for human health and well-being. However, considered in isolation, the decrease in entheseal changes and osteoarthritis presented here might be considered a positive development as they suggest overall less stress on the modern human foot. This study also has the potential to inform the health sciences and general public about biocultural contributors to modern foot health.

A retrospective magnetic resonance imaging analysis of bone and soft tissue changes associated with the spectrum of tarsal coalitions

We aimed to investigate the bone and soft tissue changes accompanying tarsal coalition (TC) and aimed to evaluate their association with the location and type of coalition. Ankle magnetic resonance imagings of 65 patients with TC were included. The relationship between the location and type of coalition and bone marrow edema, subchondral cysts, sinus tarsi syndrome, tarsal tunnel syndrome, posterior impingement syndrome, accessory bone, tibiotalar effusion, talar osteochondritis dissecans, ganglion cysts, and calcaneal spur were evaluated. Twenty-nine patients without coalition were selected as the control group, and the distribution of these variables between the two groups was analyzed. There were 33 females and 32 males in the coalition group (mean age: 42.0 ± 15.63 years), and 22 females and seven males in the control group (mean age: 44.79 ± 12.33 years). Coalition was most common in the talocalcaneal joint (n = 33, 50.8%), and the most common coalition type was non-osseous (n = 57, 87.6%). We find no significant difference between the pathologies defined in terms of coalition location and type. Sinus tarsi syndrome, tarsal tunnel syndrome, subchondral cysts, and tibiotalar effusion were found to be more common in the coalition group (p = 0.028, p = 0.010, p = 0.023, and p = 0.006, respectively). The presence of coalition increased the probability of developing tarsal tunnel syndrome 9.91 times (95% CI: [1.25-78.59]; p = 0.029), and sinus tarsi syndrome 3.66 times (95% CI: [1.14-11.78]; p = 0.029). Tarsal coalition may predispose bone and soft tissue changes. In this study, sinus tarsi syndrome, tarsal tunnel syndrome, subchondral cysts and tibiotalar effusion were found to be more common in the coalition group.

Racial differences in prevalence and anatomical distribution of tarsal coalition

Previous studies have reported a prevalence of tarsal coalition of 0.03-13%. Calcaneonavicular coalition is known as main anatomical type, and the bilateral occurrence of tarsal coalition is known to be 50% or more. These are the results of studies on Caucasians, there have been few studies targeting large number of East Asians so far. We hypothesized that the prevalence and characteristics of tarsal coalition in East Asians might differ from those in Caucasians. The medical records of 839 patients who underwent bilateral computed tomography on foot and ankle in our hospital from January 2012 to April 2021 were retrospectively reviewed. The overall prevalence was 6.0%, talocalcaneal coalition was the most common anatomical type. The overall bilateral occurrence was 56.5%, talocalcaneal coalition had the highest bilateral occurrence (76.0%) among anatomical types. Isolated union of the posterior facet was the most common subtype of talocalcaneal coalition (43.2%). Talocalcaneal coalition had a significantly higher proportion of coalition-related symptomatic patients than calcaneonavicular coalition (p = 0.019). Our study showed a similar trend to other East Asian studies, confirming the existence of racial differences. The possibility of tarsal coalition in foot and ankle patients in East Asians should always be considered, and bilateral examination is essential for diagnosis.

Lateral endoscopy of the sinus tarsi: Anatomy, technique and current indications

Numerous pathologies are reported in the lateral mid- and hind-foot. Access to the sinus tarsi is difficult, making lateral endoscopy the preferred approach. The present technical note describes the anatomy, technique and current indications for lateral endoscopy of the sinus tarsi.

Tarsal coalition resections: a long-term retrospective analysis of 97 resections in 78 patients

Background

Resection of tarsal coalitions provides good patient satisfaction scores, reduced pain, and improved long-term function in both athletic and non-athletic populations. This study aimed to determine when athletic patients undergoing resection of a tarsal coalition were able to return to their desired activity, and whether they experienced a decreased desired activity level (DDA).

Methods

Data on a total of 78 patients who underwent 97 tarsal coalition resections (49 talocalcaneal coalitions, 47 calcaneo-navicular, 14 cuboid-navicular, and three cuneo-navicular; some patients had more than one coalition) operated between January 2001 and June 2020 were prospectively collected. To subjectively assess outcomes, the Roles and Maudsley score (RM) was utilized.

Results

At an average follow-up from the index procedure of 33.6 ± 41.5 months, return to activity for the entire cohort was 18.3 ± 9.6 weeks. Post-RM was 1.3 ± 0.6.

Conclusion

Surgical excision of tarsal coalitions produced favorable results, with most patients able to return to their desired activity level.

Level of evidence

IV.

Sacral Spina Bifida Occulta: A Frequency Analysis of Secular Change

Substantial relaxation of natural selection beginning around 1900 changed the mutation/selec­tion balance of modern genetic material, producing an increase in variable anatomical structures. While multiple structures have been affected, the temporal increase in variations of the sacrum, specifically, ‘Sa­cral Spina Bifida Occulta,’ have been reliably demonstrated on a localised scale. Calculation of largescale frequency has been hindered by the localised nature of these publications, the morphological variability of this variation, and potential pathological associations, which have produced divergent classifications, and conflicting reported rates of occurrence. A systematic review of the reported literature was conducted to provide an objective analysis of Sacral Spina Bifida Occulta frequency from 2500 BCE to the present. This review was designed to compensate for observed inconsistencies in reporting and to ascertain, for the first time, the temporal trajectory of this secular trend. A systematic review of Sacral Spina Bifida Occulta lit­erature was conducted through the strict use of clinical meta-analysis criteria. Publications were retrieved from four databases: PubMed, Embase, the Adelaide University Library database, and Google Scholar. Data were separated into three historical groups, (1 = <1900, 2 = 1900 to 1980 and 3 = >1980), and frequency outcomes compared, to determine temporal rates of occurrence. A total of 39/409 publications were included in the final analysis, representing data for 16,167 sacra, spanning a period of 4,500 years. Statistically significant results were obtained, with total open S1 frequen­cy increasing from 2.34%, (79 to 1900CE), to 4.80%, (1900 to 1980CE) and to 5.43% (>1980CE). These increases were significant at p<0.0001, with Chi-squared analysis. A clear secular increase in the global frequency of Sacral Spina Bifida Occulta has been demonstrated from 1900 to the present. This research provides a novel and adaptable framework for the future assessment of variation distribution, with impor­tant implications for the fields of biological anthropology and bioarchaeology.

Tarsal coalition: Systematic review of arthroscopic management

INTRODUCTION

The standard of care in the treatment of symptomatic tarsal coalitions is open surgery. However, certain limitations exist with open surgery, which include limited visualization leading to an incomplete resection and possible recurrence of the tarsal coalition. Arthroscopic tarsal coalition resection (TCR) is an alternative that is gaining traction, primarily as the safety profile of posterior ankle and subtalar arthroscopy is more well understood. This study provides a systematic review of the outcomes of arthroscopic TCR.

METHODS

PubMed and Embase were searched independently by 2 reviewers for relevant articles based on predetermined criteria. The subject heading "tarsal coalition" and its related key terms were used.

RESULTS

A total of 416 studies were revealed by the initial search, out of which only 6 met our predetermined inclusion criteria. A total of 42 patients (average age: 17.6 years) were treated with arthroscopic TCR. Thirty-three (78.6%) and 9 (21.4%) patients had talocalcaneal and calcaneonavicular coalitions, respectively. The follow-up period ranged from 6 to 60 months (mean: 26 months), and no recurrence of the tarsal coalition was detected (0.0%). Complications occurred in two (4.8%) patients only, with one developing complex regional pain syndrome (CRPS), and another patient developing hyperesthesia on the medial aspect of the calcaneus.

CONCLUSION

Arthroscopic TCR is a feasible and effective surgery for both CNC and TCC with minimal complications and no disease recurrence at an average of 26 months follow-up. Future high-level of evidence studies are needed to compare the outcomes of open versus arthroscopic TCR.

Surgical Treatment of Calcaneonavicular and Talocalcaneal Coalitions

Tarsal coalition is determined by an absence of segmentation between one or more foot bones. The main symptom is activity-related foot pain, usually dorsolateral for calcaneonavicular coalitions and medial for talocalcaneal ones. At presentation, a symptomatic tarsal coalition must be treated conservatively for at least 6 months. If the conservative treatment fails and the foot is still painful, resection is the treatment of choice. Advantage of surgery is to restore mobility and reduce the risk of subsequent degenerative arthritis. Common pitfalls of surgery include failure to recognize associated coalitions, inadequate or extensive resection, and injury of adjoining bones.

The C-sign in normal feet: a prospective study and novel imaging algorithm for subtalar joint tarsal coalition

OBJECTIVE

The C-sign on lateral radiographs has been subject to considerable debate with respect to its reliable association to subtalar joint tarsal coalition. The purpose of this study was to determine to what degree subtalar joint pronation factors into (a) the appearance of both complete and incomplete type A C-signs and (b) the conspicuity of the middle facet in both flatfeet and rectus feet.

STUDY DESIGN

Forty-seven normal adult volunteers were enrolled into the study with a total of 92 feet, of which 42 were flexible flatfeet and 50 were rectus feet with normal subtalar joint range of motion. Lateral weight-bearing radiographs were taken of each foot in a position of (a) standing and (b) maximum subtalar joint pronation. Investigators evaluated images for the visibility of the middle facet, and the presence or absence of a continuous or interrupted type A C-sign.

PRINCIPAL RESULTS

No continuous C-signs were produced with extreme pronation in either the rectus/normal or flatfoot populations. Three incomplete type A C-signs were produced with pronation, two of which were in rectus feet. Two absent middle facet signs were also produced with pronation. Absent visualization of the facet had high positive and negative predictive values (1.00 and 0.99 respectively) for the presence of an incomplete C-Sign.

MAJOR CONCLUSIONS

The standard, routine lateral foot/ankle radiographic image protocol for suspected talocalcaneal coalition should be modified routinely positioning the foot maximally supinated, thereby minimizing the possibility of producing C-signs (complete or type A incomplete) and/or absent middle facet signs with pronation in either normal or flatfeet. A novel algorithmic approach can then be simply applied to determine when ancillary CT scanning is warranted for suspected posterior facet coalition.

Incidence of Symptomatic Pediatric Tarsal Coalition in Olmsted County: A Population-Based Study

BACKGROUND

Tarsal coalitions are an important reason for foot pain in children. Early estimates placed the prevalence at up to 2%, while more recent data suggest that it is as high as 11% to 13%. To our knowledge, there have been no population-based studies to determine the true incidence of symptomatic tarsal coalitions in a pediatric population.

METHODS

A population-based database was used to identify all new diagnoses of symptomatic tarsal coalitions in children 18 years old or younger between 1966 and 2018. Patient records were reviewed for clinical data, and comparisons were made between the types and characteristics of the coalitions identified to determine differences in the affected populations. The annual age-specific, sex-specific, and type-specific incidence rates were estimated.

RESULTS

During the study period, 58 patients with a total of 79 symptomatic tarsal coalitions were identified (annual incidence = 3.5 per 100,000 children). There were 43 calcaneonavicular (CN) coalitions (annual incidence = 1.9 per 100,000 children), 27 talocalcaneal (TC) coalitions (annual incidence = 1.2 per 100,000 children), as well as 9 other coalitions (7 talonavicular, 1 naviculocuboid, and 1 naviculocuneiform) (annual incidence = 0.4 per 100,000 children). The overall incidence peaked between the ages of 10 and 14 years for both boys and girls (8.1 per 100,000 and 7.4 per 100,000 children, respectively). Statistical differences were identified between the types of tarsal coalitions. TC coalitions present at an older age relative to CN and other coalitions (mean,13.9, 12.7, and 11.4 years, respectively; p = 0.02). While CN and TC coalitions were similar in composition (23% and 30%, respectively, were osseous as opposed to fibrocartilaginous), other coalitions were more likely to be osseous (78%) (p = 0.0035). Other coalitions were also less likely to require surgery than CN and TC coalitions (11%, 74%, and 56%, respectively; p = 0.0015).

CONCLUSIONS

This population-based study demonstrates differences in the clinical presentation of tarsal coalitions and provides an estimate of the true incidence of symptomatic tarsal coalitions in a pediatric population.

Post-operative outcomes of arthroscopic tarsal coalition resection: A systematic review

BACKGROUND

Arthroscopic resection of tarsal coalitions is a relatively new technique. This systematic review aimed to investigate the post-operative complications and functional outcomes in arthroscopic resection of tarsal coalitions.

METHODS

PubMed, Medline, Embase and Cochrane library were searched for studies that reported outcomes in arthroscopic resection of tarsal coalitions.

RESULTS

8 studies met the inclusion criteria. Post-operative outcomes were reported in 103 cases. The overall complication rate was 13.6%. Tibial nerve injury was reported in 1 patient. All included studies demonstrated post-operative improvement in functional outcomes.

CONCLUSION

Arthroscopic resection is a feasible and effective treatment method for symptomatic tarsal coalitions.

Endoscopic Resection of Tarsal Coalitions

Endoscopic resection of tarsal coalitions is technically feasible for both talocalcaneal and calcaneonavicular coalitions. Careful consideration of each individual patient is necessary before proceeding with endoscopic resection. Endoscopic resection of these coalitions may offer benefits in terms of faster recovery and less wound problems, but this has not been proven. Several case reports and case series appear in the literature and are reviewed here along with the different techniques reported. Better-quality evidence is required to assess the clinically relevant benefits and the recurrence rate for endoscopic resection in comparison with open resection.

Correlation between the accessory anterolateral talar facet, bone marrow edema, and tarsal coalitions

OBJECTIVE

The purposes of this study was to determine the prevalence of the accessory anterolateral talar facet (AALTF); to evaluate the relationship between AALTF, focal abutting bone marrow edema (FABME), and sinus tarsi edema; and to study the prevalence of tarsal coalitions in patients with the AALTF utilizing ankle MR images.

MATERIALS AND METHODS

5-T ankle MR images were reviewed for the presence of AALTF, FABME, sinus tarsi edema, tarsal coalition, and location and type of coalition (cartilaginous, fibrous, and osseous). Multivariate analysis was performed to examine the correlation between AALTF and the other variables.

RESULTS

Three hundred ninety-one consecutive patients were included (age range 5-86 years; mean age 45 years). An AALTF was present in 3.6% (14/391) of patients. The AALTF prevalence was 2% in women and 6.6% in men. There was a significantly association between AALTF and FABME (9/14, p < 0.05), sinus tarsi edema (13/14, p < 0.05), and tarsal coalition (4/14, p < 0.05).

CONCLUSION

AALTF is relatively often detected on MRI of the ankle and significantly associated with BME, sinus tarsi edema, and subtalar coalition. Patients with a tarsal coalition should be evaluated for the concurrent presence of an AALTF.

Surgical treatment of tarsal coalitions in children and adolescents

A tarsal coalition is an abnormal connection between two or more tarsal bones caused by failure of mesenchymal segmentation.

The two most common tarsal coalitions are calcaneonavicular coalition (CNC) and talocalcaneal coalition (TCC). Both CNC and TCC can be associated with significant foot and ankle pain and impaired quality of life; there may also be concomitant foot and ankle deformity.

Initial, non-operative management for symptomatic tarsal coalition commonly fails, leaving surgical intervention as the only recourse.

The focus of this article is to critically describe the variety of methods used to surgically manage CNC and TCC. In review of the pertinent literature we highlight the ongoing treatment controversies in this field and discuss new innovations.

The evidence-based algorithmic approach used by the authors in the management of tarsal coalitions is illustrated alongside some clinical pearls that should help surgeons treating this common, and at times complex, condition.

Cite this article: EFORT Open Rev 2020;5:80-89. DOI: 10.1302/2058-5241.5.180106

Diagnosing tarsal coalition in medieval Exeter

OBJECTIVE

The objective of this study is to estimate the frequency and types of tarsal coalition represented in medieval remains from Exeter, England.

MATERIALS

183 individuals from the Cathedral Green site in Exeter, England.

METHODS

Gross macroscopic analysis combined with radiographic examination and comparison with clinical and archaeological literature.

RESULTS

Eight coalitions of various forms were ultimately identified; these include five calcaneonavicular, one talocalcaneal, one calcaneocuboid, and one lateral cuneiform-third metatarsal coalition.

CONCLUSIONS

These frequencies are quite high for clinical imaging estimations, but consistent with other reported archaeological frequencies.

SIGNIFICANCE

This study contributes to known frequencies of tarsal coalition in the past. It also provides descriptive diagnostic criteria for identifying tarsal coalition in archaeological populations.

LIMITATIONS

Poor preservation of some of the individuals in this sample means that the true frequencies of tarsal coalition may be underrepresented.

SUGGESTIONS FOR FURTHER RESEARCH

This study should be expanded to include more archaeological sites, especially medieval British sites, to determine overall prevalence rates. Additionally, the diagnostic criteria should be compared with other examples of known tarsal coalition to further our understanding of this rare pathology.

Tarsal coalition in paediatric patients

Tarsal coalition is due to failure of segmentation between two or more foot bones during embryological development at a site where the joint cleft fails to develop. Depending on the nature of the tissue connecting the bones, the abnormality is a syndesmosis, synchondrosis, or synostosis. Although the coalition exists at birth, synostosis usually develops only late during growth. Talo-calcaneal and calcaneo-navicular coalitions account for over 90% of all cases of tarsal coalition. The joint at the site of the coalition is stiff. Pain during physical activity is the main symptom, although recurrent ankle sprain is another possible presenting manifestation. During the physical examination, range-of-motion limitation at the hindfoot or midfoot should be sought, as well as varus or valgus malalignment of the hindfoot. Either pes planus or pes cavus may be seen. Calcaneo-navicular coalition may be visible on the standard radiograph, whereas talo-calcaneal coalition is best visualised by computed tomography or magnetic resonance imaging. As growth proceeds, the coalition becomes ossified and range-of-motion diminishes. Onset of the pain is often in the second decade of life or later. In patients with symptomatic tarsal coalition, the initial management should always consist in non-operative treatment for at least 6 months. A consensus exists that surgery should be offered when non-operative treatment fails. Open resection of the coalition is the treatment of choice, although endoscopic resection is also an option. Sound evidence exists that resection of the coalition can produce favourable outcomes even in the long-term. Fusion should be reserved for failure of resection, extensive coalitions, multiple coalitions, and patients with advanced osteoarthritis.

Treatment of isolated talonavicular coalition: Case report and literature review

Tarsal coalition refers to an abnormal fibrous, cartilaginous, or bony connection that develops between two or more tarsal bones. Talocalcaneal coalition and calcaneonavicular coalition account for more than 90% of all cases of tarsal coalition. Coalition exists early at birth, but bony connection usually develops during the patient's late growth period. Isolated cases of talonavicular coalition have rarely been reported. We herein report a case involving an 11-year-old patient with an isolated talonavicular coalition from a soft tissue to bony connection who was treated with arthroscopy for ankle arthritis. To our knowledge, this is the first case in which the whole formation of the talonavicular coalition was observed with a series of radiographic and magnetic resonance imaging examinations. The pain caused by the talonavicular coalition was managed by nonoperative treatment, while the ankle pain caused by the arthritis was relieved after ankle arthroscopy. At 6 years postoperatively, the patient remained pain-free while walking for 30 minutes and was satisfied with the operative outcome. Continuous follow-up confirmed that after the formation of talonavicular coalition, the coalition can continue to progress, forming bony talocalcaneal coalition and calcaneocuboid coalition.

Coalitions of the Tarsal Bones

Tarsal coalitions are the result of impaired mesenchymal separation of the tarsal bones. The most common types include calcaneonavicular or talocalcaneal coalitions. Subtalar stiffness results in pathologic kinematics with increased risk of ankle sprains, planovalgus foot deformity, and progressive joint degeneration. Resection of the coalition yields good results. Tissue interposition may reduce the risk of reossification, and concomitant deformity should be addressed in the same surgical setting.

Subtalar coalition in pediatrics

Subtalar tarsal coalition is an autosomal dominant developmental maldeformation that affects between 2% and 13% of the population. The most common locations are between the calcaneus and navicular and between the talus and calcaneus. If prolonged attempts at nonoperative management do not relieve the pain, surgery is indicated. The exact surgical technique(s) should be based on the location of the pain, the size and histology of the coalition, the health of the other joints and facets, the degree of foot deformity, and the excursion of the heel cord.

Talocalcaneal tarsal coalitions and the calcaneal lengthening osteotomy: the role of deformity correction

BACKGROUND

Surgical resection of persistently painful talocalcaneal tarsal coalitions may not reliably relieve symptoms in patients with large coalitions associated with excessive hindfoot valgus deformity and subtalar posterior facet narrowing. Since 1991, calcaneal lengthening osteotomy, with or without coalition resection, has been used at our institution to relieve symptoms and to preserve motion at the talonavicular and calcaneocuboid joints.

METHODS

We retrospectively reviewed the records for eight patients with thirteen painful talocalcaneal tarsal coalitions who had undergone a calcaneal lengthening osteotomy for deformity correction with or without coalition resection between 1991 and 2005. Preoperative and postoperative clinical, radiographic, and computed tomographic records were reviewed. The duration of clinical follow-up ranged from two to fifteen years.

RESULTS

Calcaneal lengthening osteotomy fully corrected the valgus deformity and provided short-to-intermediate term pain relief for the five patients (nine feet) in whom the talocalcaneal tarsal coalition was unresectable. The patient with resectable coalitions but excessive valgus deformities underwent calcaneal lengthening osteotomies along with coalition resections and had excellent deformity correction and pain relief in both feet. One of the two patients who underwent calcaneal lengthening osteotomy years after coalition resection had excellent correction and pain relief. The other patient had a coincident calcaneonavicular coalition and severe degenerative arthritis in the talonavicular joint. He underwent concurrent arthrodesis of the talonavicular joint and, although he had excellent deformity correction, had persistent pain. All feet underwent concurrent gastrocnemius or Achilles tendon lengthening.

CONCLUSIONS

It is generally accepted that resection is the treatment of choice for an intractably painful small talocalcaneal tarsal coalition that is associated with a wide, healthy posterior facet and minimal valgus deformity of the hindfoot. Although triple arthrodesis has been recommended for those who do not meet all three criteria, the present study suggests that an algorithmic treatment approach is justified. Treatment of the valgus deformity appears to be as important as that of the coalition. Calcaneal lengthening osteotomy with gastrocnemius or Achilles tendon lengthening is effective for correcting deformity and relieving pain in rigid flatfeet, just as it is in flexible flatfeet.

Normal genetic variation of the human foot: Part 2: Population variance, epigenetic mechanisms, and developmental constraint in function

Congenital deformities of the foot have been reported to correlate with regulatory epigenetic mechanisms that are also responsible for the timing and sequencing of developmental growth of the lower limb. Developmental variance of normal morphologic features has also been shown to vary between populations despite the retention of human foot characteristics. The molecular evidence for genetically controlled expressions of common evolved physical features is highly suggestive of regulatory control mechanisms that act together with developmental constraints to homogenize the retained functional characteristics of the foot. Genetic variance in morphologic features and functional plasticity when linked to morphometric change during gait may prove influential in clarifying kinematic and kinetic relationships.

Significance of sesamoid ossification in peroneus longus tendon ruptures

Ruptures of the peroneus longus tendon are uncommon, with a small number of case reports found in published studies. The presence of an os peroneum can predispose the peroneus longus tendon to rupture at the cuboid level with or without concomitant fracture, or fracture through a partite os peroneum. Whether the os peroneum can be represented by various stages of ossification is still a matter of debate. We present 2 cases of acute peroneus longus tendon rupture at the cuboid notch in the presence of an intact os peroneum in the ossified and nonossified form. We treated patients with excision of the os peroneum and tenodesis of the peroneus longus to the peroneus brevis tendon.

Unilateral subtalar coalition: contralateral sustentaculum tali morphology

PURPOSE

To measure and compare the dimensions of the sustentaculum tali (ST) in pediatric patients with unilateral subtalar coalition to determine if the contralateral side has altered morphology.

MATERIALS AND METHODS

The institutional review board approved this study, which was HIPAA compliant. Informed consent was waived. Radiology records were reviewed to identify 35 patients with unilateral subtalar coalition undergoing computed tomography (CT) (21 male, 14 female; mean age, 14.54 years) and 33 control patients with triplane fracture (21 male, 12 female; mean age, 13.48 years). CT images were reviewed, and reformatted images through the subtalar joint (on the side opposite the coalition) were created. Anteroposterior measurements of the middle facet (MF) and the ST were recorded by two observers with electronic calipers. The MF/ST ratio and the ST length extending posterior to the MF were calculated. Measurements between groups were compared by using Wald tests based on linear regressions. Inter- and intraobserver variabilities were determined by means of a component of variance model.

RESULTS

The lengths of the MF and ST for the study and control groups were 12.86 and 16.82 mm (P < .001) and 23.83 and 22.06 mm (P = .053), respectively. Intra- and interobserver correlations for both measurements were 0.94 and 0.92 and 0.86 and 0.77, respectively. MF/ST ratio was 0.54 versus 0.76 (P < .001), and ST length extending posterior to the MF was 10.97 versus 5.24 mm (P < .001).

CONCLUSION

The MF is smaller and the ST extends further beyond the MF in patients with a contralateral subtalar coalition than in control patients. The morphology of the ST may provide insight into the origins and development of coalitions.

Tarsal coalitions

A tarsal coalition is an aberrant union between 2 or more tarsal bones and can be classified as osseous (synostosis) or nonosseous (cartilaginous [synchondrosis] or fibrous [syndesmosis]). This union may be complete or partial and the joints in the hindfoot and midfoot are most commonly affected. The resulting abnormal articulation presents as a noncorrectable flat foot, usually during adolescence, leading to accelerated degeneration within adjacent joints. An understanding of the condition and presenting symptoms enable the clinician to correctly diagnose and initiate appropriate treatment. This review discusses the evidence-based literature on the cause, diagnosis, and current management of tarsal coalition.

High incidence of the os peroneum in a cadaver sample in Johannesburg, South Africa: possible clinical implications?

This study set out to investigate the incidence of the os peroneum in a cadaver sample from Johannesburg, South Africa and to note how bio-demographic parameters affect such incidence. The os peroneum (OP) is a sesamoid bone frequently found in the tendon of the fibularis longus muscle (FLM), as it passes on the plantar aspect of the cuboid bone. While this bone is often an incidental dissection room or radiological finding, OP fractures, with or without associated rupture of the fibularis (peroneus) longus tendons have been reported. Some investigators have also suggested that the presence of the OP may render the tendon of the FLM susceptible to avulsion injuries. The reported incidences of the OP range between 8 and 26%. These data have emanated by and large from radiographic rather than dissection studies, and the influences of biological indices such as age, sex, population group of origin, and side of the body on these incidences remain largely unknown. Forty cadavers (average age = 75 years) were dissected. Os peronei were present in 36 of these cadavers (90.0%), with 96% of them occurring bilaterally. This bilateral incidence was statistically significant (P = 0.007), but there was no significant difference in age (P = 0.38), sex (P = 0.97), or population group (P = 0.17). We hope that the unusually high incidence of the OP reported here will stimulate further research into possible predisposing factors as well as into the speculated associations between sesamoid occurrence, osteoarthritis, and tendon injuries.

Hyperostosis frontalis interna: archaeological evidence of possible microevolution of human sex steroids?

Hyperostosis frontalis interna is a restricted bilateral thickening of the frontal endocranial surface, which is frequently found in postmenopausal females today. Surprisingly, this condition had a higher male prevalence in its rare archaeological records. This is again highlighted by the oldest known male European hyperostosis frontalis interna case in an adult Celtic from 100 BC presented here. This unique specimen supports earlier suggestions of the possible microevolution of human endocrine regulation, e.g. by sex steroids, and its pathoanatomical impact.