Fibrous dysplasia arising from the calcaneus

A case of an 18-year-old woman with fibrous dysplasia arising in the calcaneus, which is extremely rare, is reported, with the emphasis placed on differential diagnosis from low-grade central osteosarcoma. She had a severe pain in her left ankle after sprain. Plain radiographs showed a radiolucent lesion measuring 6.3 x 2.5 cm with a sclerotic margin in the left calcaneus. CT scans showed a well-defined lytic lesion with disruption of the lateral cortex and an ossification or calcification in its center. On MR imaging, the lesion had isointensities and high intensities on T1 and T2 weighted images, respectively, but its central portions showed lower intensities both on T1 and T2 weighted images. The lesion was enhanced with gadolinium except for the central portions. The specimen obtained by open biopsy consisted of fibrous tissue and foci of irregular woven bone. None of the nuclear atypia, mitoses, longitudinal stream of bone or invasive nature of growth was detected. The diagnosis of fibrous dysplasia was histologically made. The lesion was curetted and packed with autogenous bone chips. No evidence of recurrence was noted postoperatively.

Hematogenous calcaneal osteomyelitis in children

This study reviewed 21 cases of hematogenous osteomyelitis of the calcaneus in skeletally immature patients. The average patient age was 2.9 years. Local tenderness, swelling, and erythema were the most common findings. The erythrocyte sedimentation rate was elevated in 20 (95%) of 21 patients, whereas the C-reactive protein was abnormal in only seven (47%) of 15 patients tested. Nine patients had positive cultures, with Staphylococcus aureus being the most common organism. Plain films showed a lytic lesion in 15 (71%) of 21 cases, whereas scintography was positive in all 16 cases scanned. Ten patients were treated with antibiotics alone, whereas 11 patients underwent surgical irrigation and debridement in association with antibiotic therapy. Seventeen patients returned for follow-up, and although only one was symptomatic, three of 10 follow-up radiographs revealed residual abnormalities of the calcaneus.

MRI-induced retrocalcaneal bursitis

This case report describes a patient with acute retrocalcaneal bursitis, which developed after MRI examination of the ankle. The sagittal T2*-weighted gradient echo sequence revealed an extensive susceptibility artifact in the area surrounding the Achilles tendon near its insertion at the os calcis. This artifact was caused by postsurgical metallic particles. We postulate that these particles were mechanically stimulated by the magnetic field and induced the inflammatory response.

Synovial osteochondromatosis of the retrocalcaneal bursa: a case study

A 42-year-old man presented with synovial osteochondromatosis (SO) of the retrocalcaneal bursa with intraosseous lesions in the calcaneum, leading to significant pain and consequent disability. Simple x-rays, computed tomography, and magnetic resonance imaging were performed preoperatively. The patient has remained asymptomatic, clinically and radiographically, without recurrent lesions for 18 months postoperatively.

Nonoperative treatment of posterior tibial tendon dysfunction

One of the most common causes of acquired flatfoot deformity in adults is dysfunction of the posterior tibial tendon. The main function of the posterior tibial tendon is to invert the midfoot and lock the transverse tarsal joints (talonavicular and calcaneocuboid joints). When the tendon fails to function properly, a progressive flatfoot deformity develops. Because the disease process is a continuum, a staging system has been devised to offer guidelines for nonoperative and operative treatment of this problem. The rationale for nonoperative treatment of this disorder is to support the longitudinal arch and to decrease the valgus angulation of the calcaneus for flexible flatfoot deformity, and to immobilize and support the hindfoot and midfoot for rigid flatfoot deformities. The success of nonoperative treatment first requires the assessment of the flexibility of the flatfoot deformity. For a flexible deformity, the custom orthosis should be fitted with the foot and ankle in a corrected position as close to the neutral position as possible. Whereas, for a rigid deformity, it is imperative for the custom orthosis to be fitted with the affected foot and ankle in an in situ position.

[Solitary juvenile cyst of the heel bone. Two case reports and review of the literature]

The calcaneus is a uncommon site for a unicameral solitary bone cyst. However, because of the concentration of forces through the heel, such solitary bone cysts are usually symptomatic, depending on the proximity to the joint and the size of the cyst and therefore require in most cases surgical treatment. This is a report about two patients with a solitary bone cyst of the os calcis in 1996 and 1997. The diagnosis was confirmed radiologically and histologically. The standard therapie in both cases was the curretage of the cyst by packing the defect with bone graft from the pelvis. The author reviewed the literature concerning ethiology, diagnosis and treatment of unicameral solitary bone cysts of the calcaneus. The diagnosis cannot be based solely on radiological findings because of the variation of solitary bone cysts and the special forms, such as calcifying solitary bone cysts. Therefore exact histological diagnosis is of particular importance.

An accessory ossification centre in the calcaneus with talonavicular and second metatarsocuneiform coalitions

We present the case of an 11-year-old girl with an accessory ossification centre of the calcaneus with talonavicular and second metatarsocuneiform coalitions, and bilateral os tibiale externum.

Magnetic resonance imaging of the normal and injured lateral collateral ligaments of the ankle

BACKGROUND AND AIMS

To study the role of MR Imaging in evaluating both normal and injured lateral collateral ligaments of the ankle.

MATERIALS AND METHODS

Twenty-four patients with clinically diagnosed inversion injury to the ankle and 20 healthy volunteers underwent Magnetic Resonance Imaging (MRI) of the ankle with special emphasis on the lateral complex ligaments.

RESULTS

The anterior talofibular (ATFL) and posterior talofibular ligaments (PTFL) were identified in 100% of the ankles of normal volunteers in the axial plane. The PTFL was identified in 100% in the coronal plane. The calcaneofibular ligament (CFL) was identified in 76% of the ankles in the axial, 84% in the coronal and 88% in the sagittal plane. Of the 24 patients with inversion injury, MRI showed ligament abnormalities in 16 patients, ten of these were isolated ATFL tears, five had combined ATFL and CFL tears and one case showed in addition abnormal signal in the PTFL. MRI revealed associated injuries to other ligaments and other soft tissue and osseous structures of the ankle in twelve patients.

CONCLUSION

MRI is a non-invasive, accurate technique for evaluation of the normal and injured lateral collateral ligaments of the ankle.

Clubfoot analysis with three-dimensional foot models

The purpose of this study was to develop a method of defining, in mathematical terms, the interpositional relationships of the bones of the hindfoot complex in the idiopathic clubfoot and the neurogenic clubfoot. The neurogenic clubfoot and contralateral normal-appearing foot of a stillborn infant with myelomeningocele, and the normal foot of a 10-year-old were sectioned with a cryomicrotome. Magnetic resonance images (MRIs) of the clubfoot and the normal foot of a 3-month-old boy were obtained. Using a computer program, three-dimensional foot models were generated from the digitized cryomicrotome sections and from the MRIs. The central principal axes were determined for the talus and calcaneus. The long central principal axes of the talus and calcaneus were neutrally rotated with reference to the bimalleolar axis in the idiopathic clubfoot while in the neurogenic clubfoot the long central principal axis of the talus was medially rotated 52 degrees and that of the calcaneus 10 degrees. The talocalcaneal angles defined by the long central principal axes in the superior and medial views were 0 degree and 10 degrees, respectively, in the idiopathic clubfoot, and 42 degrees and 56 degrees, respectively, in the neurogenic clubfoot.

Ewing's sarcoma of os calcis: case report with a review of literature

A rare case of Ewing's sarcoma of os calcis is described here. Its atypical clinical and radiological features often delay the diagnosis. These features and review of literature are discussed.

[MRI of plantar fasciitis]

PURPOSE

The purpose of this study was to determine the type and frequency of characteristic bone and soft tissue changes on MRI of patients with a clinical diagnosis of plantar fasciitis.

MATERIALS AND METHODS

28 patients with a clinical diagnosis of plantar fasciitis underwent MR imaging. Besides T1- and T2-weighted sequences, short-tau-inversion-recovery sequences were used routinely. In 27 patients T1-weighted images after intravenous contrast injection were acquired additionally. As a control group the images of 15 patients without clinical signs for plantar fasciitis were evaluated.

RESULTS

In 25 of 28 cases (89%) the clinical diagnosis of plantar fasciitis was established by MR imaging. The most common finding was a peritendinous edema at the calcaneal insertion site which was found in all 25 patients. In 19 of 25 cases (76%) a bone marrow edema of the calcaneus was present. In 14 of 25 cases (56%) an intratendinous signal intensity increase of the plantar fascia could be observed which showed contrast enhancement in 12 cases. Compared to the control group (mean thickness 3.3 mm) the plantar fascia showed significant thickening in the 25 MR positive patients (mean thickness 6.72 mm).

DISCUSSION

Besides thickening of the plantar fascia and intratendinous signal intensity increase with contrast enhancement to some extent, bone marrow edema of the calcaneus and peritendinous edema close to the plantar fascia are characteristic signs of plantar fasciitis on MRI. Both signs can reliably be seen on STIR sequences only.

Assessment of hindfoot deformity by three-dimensional MRI in infant club foot

In 12 infants aged under 16 months with unilateral club foot we used MRI in association with multiplanar reconstruction to calculate the volume and principal axes of inertia of the bone and cartilaginous structures of the hindfoot. The volume of these structures in the club foot is about 20% smaller than that in the normal foot. The reduction in volume of the ossification centre of the talus (40%) is greater than that of the calcaneus (20%). The long axes of both the ossification centre and the cartilaginous anlage of the calcaneus are identical in normal and club feet. The long axis of the osseous nucleus of the talus of normal and club feet is medially rotated relative to the cartilaginous anlage, but the angle is greater in club feet (10 degrees v 14 degrees). The cartilaginous structure of the calcaneus is significantly medially rotated in club feet (15 degrees) relative to the bimalleolar axis. The cartilaginous anlage of the talus is medially rotated in both normal and club feet, but with a smaller angle for club feet (28 degrees v 38 degrees). This objective technique of measurement of the deformity may be of value preoperatively.

Acute and subacute changes in the ultrasound measurements of the calcaneus following intense exercise

The amount of exercise necessary to cause bone structural change in humans is unknown. We examined whether a single bout of intense exercise in vivo leads to acute and subacute changes in the physical properties of bone as measured by ultrasound. It was hypothesized that structural changes such as accumulation of fatigue microdamage would result in a decrease in velocity of sound (VOS) and broadband ultrasound attenuation (BUA) across the calcaneus. We performed a prospective cohort study in 111 (97 M, 14 F) entrants of the 1996 Melbourne marathon (42.3 km) and 28 (10 M, 18 F) nonrunning controls. Runners had a mean (SD) age of 45.3 +/- 11.4 years (range 20-75), had completed 15.2 +/- 17.3 prior marathons (0-88), and had been running regularly for 14.2 +/- 9.2 years (0.25-50). An ultrasound densitometer (Cuba Clinical, McCue) was used to measure VOS and BUA across the right calcaneus. Runners were tested on three occasions: 1-3 days prior to, immediately after (<2 hours), and 5-6 days following the marathon. Seventy-three (66%) runners presented for all three measurements. Controls were tested on three occasions with the same time intervals as the runners. BUA values in the runners were significantly elevated by 5.0% immediately after the marathon but returned to baseline levels by the third test session (P = 0. 0001). Changes in BUA values in the controls were not significant and all were less than 0.7% (P = 0.88). Age was a significant independent predictor of the BUA change between test 1 and test 2 in the runners (beta = 0.2094; SE = 0.0917; P = 0.03). VOS measurements were not significantly different across the three testing sessions in both the runners (P = 0.07) and the controls (P = 0.33). Therefore, ultrasound measurements of BUA and VOS did not detect evidence of lasting structural change in the calcaneus following a marathon.

Bone mineral assessments in the calcaneus after anterior cruciate ligament injury. An investigation of 92 male patients before and two years after reconstruction or revision surgery

The aim of this study was to assess the Bone Mineral Areal mass (BMA) in the calcaneus of male patients with unilateral anterior cruciate ligament (ACL) injury before and after reconstruction and to assess whether the BMA ratio or the BMA of the injured and uninjured side correlated with the level of activity, functional performance or the time period between the injury and the reconstruction. Ninety-two male patients with unilateral ACL injury were included in the study. The BMA was analysed immediately prior to surgery: a median of 11 (2-192) months after the injury in 30 patients aged 26 (15-41) years scheduled for primary ACL reconstruction (Group A). Forty-nine patients aged 29 (18-49) years had their BMA analysed a median of 24 (23-29) months after the primary ACL reconstruction (Group B). Thirteen patients aged 27 (21-39) years had their BMA analysed a median of 24 (20-45) months after ACL revision surgery (Group C). The median BMA ratio (injured side/uninjured side) was 96 (88-105)% in Group A, 96 (86-118)% in Group B and 95 (83-111)% in Group C. In all three groups, the median BMA value in the calcaneus was significantly lower on the injured side compared with the uninjured side (P=0.001, P=0.0003, P=0.01 in Groups A, B and C, respectively). The time period between the injury and the reconstruction neither correlated with the BMA ratio nor the BMA of the injured or the uninjured side in Group A. The level of activity as measured by the Tegner activity level and the functional performance as measured by the one-leg-hop quotient did not correlate with the BMA ratio in any of the groups. In the 49 patients with a primary ACL reconstruction (Group B), the post-operative Tegner activity level correlated with the BMA, on both the injured and uninjured side (P=0.0003, P=0.0005, respectively), when the BMA was assessed two years after the index operation. Male patients with unilateral ACL injury had a significantly lower BMA in the calcaneus on the injured side compared with the uninjured side before primary reconstruction, two years after primary reconstruction and two years after revision surgery. The time period between the injury and the index operation did not correlate with the BMA. A high level of activity correlated with the BMA on both the injured and the uninjured side two years after primary reconstruction.

Intra-articular calcaneal fractures: effect of open reduction and internal fixation on the contact characteristics of the subtalar joint

Intra-articular calcaneal fractures are associated with significant long-term morbidity, and considerable controversy exists regarding the optimum method of treating them. The contact characteristics in the intact subtalar joint were determined at known loads and for different positions of the ankle and subtalar joint, using pressure-sensitive film (Super Low; Fuji, Itochu Canada Ltd, Montreal, Quebec). We measured the contact area to joint area ratio (pressure > 5 kg force/cm2 [kgf/cm2]) which normalizes for differences in joint size and the ratio of high pressure zone (>20 kgf/cm2) as a reflection of overall increase in joint pressure. Three simulated fracture patterns were then created and stabilized with either 1 or 2 mm of articular incongruity. Eight specimens were prepared with a primary fracture line through the posterior facet, eight with a joint depression-type fracture, and six with a central joint depression fracture. A measure of 1 to 2 mm of incongruity in the posterior facet for all three fracture patterns produced significant unloading of the depressed fragment, with a redistribution of the overall pattern of pressure distribution to parts of the facet that were previously unloaded.

Operative management of Haglund's deformity in the nonathlete: a retrospective study

Haglund's deformity, or "pump bump," is a common cause of posterior heel pain. Management of the condition usually consists of nonoperative therapy. This study presents a retrospective study of 65 cases (53 patients), with symptomatic Haglund's deformity in nonathletes (13 male and 40 female), who presented during a 4-year period (1989-1994). Sixty-five percent (39 heels) of these patients failed to respond to nonoperative therapy for an average of 62 weeks, (range, 4-260 weeks). This group of patients went on to operative treatment. Surgical management consisted of excision of the posterior calcaneal tuberosity through a medial longitudinal incision with debridement, reattachment of the Achilles tendon using bone anchors, and 4 weeks of postoperative immobilization. Thirty-nine patients (74%) were contacted for follow-up. The average follow-up period for these patients was 155 weeks, (range, 92-335 weeks). There were 50% excellent results, 47% good results, 3% fair results (1 patient), and no poor results. The Maryland Foot Score for operated heels was an average of 67/100 preoperative and an average of 92/100 postoperative. On unoperated heels the score was an average of 81/100 at first evaluation and an average of 86/100 at final evaluation. Complications included one recurrence of painful prominence, one wound infection, and one incisional neuroma. The outcome of these cases demonstrated that in those patients who fail nonoperative treatment, surgical treatment of Haglund's deformity produces a predictably good surgical result when performed using the technique described.

[Computer-assisted structure analysis of trabecular bone in the diagnosis of osteoporosis]

Osteoporosis is characterized by reduced bone mass and a deterioration of bone structure which results in an increased fracture risk. The purpose of this review is to evaluate structure analysis techniques in the diagnosis of osteoporosis. Several imaging techniques were applied to analyze trabecular bone, such as conventional radiography, high-resolution computed tomography (HR-CT) and high-resolution magnetic resonance imaging (HR-MRI). The best results were obtained using high-resolution tomographic techniques. The highest spatial resolutions in vivo were achieved using HR-MRI. These studies show that texture parameters and bone mineral density predict bone strength and osteoporotic fractures in a complementary fashion. Combining both techniques yields the best results in the diagnosis of osteoporosis.

[Essential bone cyst of the calcaneus in children. Report of three cases]

OBJECTIVE

The purpose of this study was to analyze the properties of essential bone cyst of the calcaneus in childhood, as well as its evolution, and differences with regard to adults.

PATIENTS AND METHODS

The cases of children with a diagnosis of essential bone cyst of calcaneus in last sixteen years in the pediatric orthopedic unit of San Carlos Clinic have been reviewed. We evaluated the information regarding the clinical history and the radiological and histological date as well as the therapy result with esteroid intracavity therapy and curettage and bone grafting. The radiologic score was done following Södergard criteria and the posttreatment follow-up with Neer's score.

RESULTS

The mean age of the patients was 10.3 years. Two of the patients had recurrent heel pain for more than six months. Treatment consisted in intracavitary esteroid in two cases and curettage and bone grafting in all three cases, in two of the cases because of failure of esteroid therapy and in the other because of an atypical X-ray image. In all cases the histological stady identified the existence of a characteristic membrane conective tissue. The postsurgery follow-up a period of half four years has been satisfactory.

CONCLUSIONS

The essential bone cyst of the calcaneous is exceptional localization in children, frequently symptomatic and resistant to the esteroid intracavitaria contrary to what happens with the essential bone cyst of other localizations and with the essential bone cyst of the calcaneus in the adults. The recurrent heel pain and atipical X-ray image are surgery indications.

[Our method of treatment of dislocated fractures of the heel bone (preliminary report)]

The authors present first experience with their method of treatment of displaced fractures of calcaneus. The method is based on the combination of direct and indirect reposition of fragments and exact fixation with K-wires. Axial and AP X-ray and 2 plane CT scan are indispensible conditions for operation planning. The procedure can be divided into 4 phases: traction, elevation, compression, transfixation. Up till now 65 patients have been treated with this method. 20 patients with 24 fractures were evaluated according to the Creighton-Nebraska Health Foundation score in the interval 24 months after the operation. The average value of the score was 96.6 points, 16 patients were evaluated as excellent, in 2 patients the result was good.

Perimortem calcaneal and talar fractures sustained in a military air crash in Vietnam

The authors report on the skeletal elements of a minimum of 37 men who died in 1965 when their C-123 cargo airplane crashed into a mountainside in South Vietnam. Natural environmental processes reduced their bodies to skeletons; these osseous remains were recovered from the crash site nearly 10 years later. Among the remains were the calcanei and tali of at least 37 people. These bones, devoid of soft tissue, provide a rare opportunity to examine and document the pattern of perimortem fractures in multiple individuals who died in the same incident. This case also provides information on a range of variability of skeletal fractures that is unavailable in comparative skeletal collections, and that might be overlooked with radiography or during physical examination.

In vivo high resolution MRI of the calcaneus: differences in trabecular structure in osteoporosis patients

The purpose of this study was to use high resolution (HR) magnetic resonance (MR) images of the calcaneus to investigate the trabecular structure of patients with and without osteoporotic hip fractures and to compare these techniques with bone mineral density (BMD) in differentiating fracture and nonfracture patients. Axial and sagittal HR MR images of the calcaneus were obtained in 50 female (23 postmenopausal patients with osteoporotic hip fractures and 27 postmenopausal controls). A three-dimensional gradient-echo sequence was used with a slice thickness of 500 micron and in plane resolution of 195 x 195 micron. Texture analysis was performed using morphological features, analogous to standard histomorphometry and fractal dimension. Additionally, BMd measurements of the hip (dual-energy X-ray absorptiometry) were obtained in all patients. Significant differences between both patient groups were obtained using morphological parameters and fractal dimension as well as hip BMD (p < 0.05). Odds ratios for the texture parameters apparent (app.) bone volume/total volume and app. trabecular separation were higher than for hip BMD. Receiver operator characteristic values of texture measures and hip BMD were comparable. In conclusion, trabecular structure measures derived from HR MR images of the calcaneus can differentiate between postmenopausal women with and without osteoporotic hip fractures.

MR imaging of the normal and abnormal retrocalcaneal bursae

OBJECTIVE

The aim of this study was to define the MR imaging criteria for normal and abnormal retrocalcaneal bursae.

SUBJECTS AND METHODS

Fifty ankles in 25 asymptomatic volunteers and 30 ankles in patients with Achilles tendon disorders underwent MR imaging. Increased signal intensity consistent with fluid or synovium outlining the retrocalcaneal bursa was measured.

RESULTS

Of 80 bursae, 77 (96%) had measurable fluid or synovial signal intensity revealed by MR imaging. Asymptomatic volunteers had average bursal dimensions of 1 mm in the anteroposterior dimension, 6 mm in the transverse dimension, and 3 mm in the craniocaudal dimension. Bursal dimensions greater than 1 mm, 11 mm, or 7 mm, respectively, were not seen in asymptomatic subjects but were seen in 16 (53%) of 30 ankles of patients with Achilles tendon disorders.

CONCLUSION

On MR imaging, the asymptomatic retrocalcaneal bursa normally contains detectable high-signal-intensity fluid or synovium or both. A bursa larger than 1 mm anteroposteriorly, 11 mm transversely, or 7 mm craniocaudally is abnormal.

Paget disease of the calcaneus: findings on MR imaging

We present a case of Paget disease of the calcaneus with an emphasis on its magnetic resonance imaging features.

Rare presentation of hereditary multiple exostoses. A case report

Hereditary multiple exostoses is a relatively uncommon disorder of endochondral bone characterized by the presence of multiple, cartilaginous-capped exostoses arising from the metaphyses. A rare presentation of hereditary multiple exostoses in the calcaneus of a 35-year-old man is reviewed and discussed. A brief review of the literature is provided, as well as a discussion of the patient's family history.

Pathoanatomy of intra-articular fractures of the calcaneus

Radiographs of 220 calcaneal fractures (205 patients) were reviewed retrospectively. One hundred and sixty-three fractures were intra-articular; thirty (18 per cent) of the 163 fractures were a tongue-type injury, and 133 (82 per cent) were a joint-depression injury. Plain radiographs and computerized tomography scans in the coronal and axial planes were available for 116 intra-articular fractures (106 patients). These studies were reviewed, and the 116 fractures were grouped according to the Sanders classification of calcaneal fractures and the anterior extension of the primary fracture line was evaluated. Sixty-two primary fracture lines (53 per cent) extended into one articular surface; twenty-three (20 per cent), into two articular surfaces; twenty-three (20 per cent), into a periarticular location; and eight (7 per cent), into a medial or lateral location. Sixty-seven (58 per cent) involved the calcaneocuboid joint, thirty-one (27 per cent) involved the anterior facet of the talocalcaneal joint, and ten (9 per cent) involved the middle facet of the talocalcaneal joint. A distinct anterolateral fragment was identified in 108 fractures (93 per cent). Plain radiographs failed to demonstrate the anterior extension of fifty-one (47 per cent) of the primary fracture lines. The prevalence of involvement of the anterior facet was significantly greater in Sanders type-III fractures (sixteen of thirty-five; 46 per cent) than in the other types (p < 0.01). The prevalence of involvement of the calcaneocuboid joint and the middle facet was evenly distributed among the fracture types. The primary fracture line typically extends anterior to the angle of Gissane, creating a relatively consistent anterolateral fracture fragment. The primary fracture line cannot be reliably seen on plain radiographs and is better visualized on computerized tomographic scans.

Resectional arthroplasty: treatment for calcaneonavicular coalition

In a 10-year retrospective review of one practitioner's experience with calcaneonavicular tarsal coalitions, a diagnostic procedure based on clinical and radiographic examination is described. What typically may present as heel pain, on thorough clinical examination, may be identified more specifically as midtarsal pain. Radiographically degenerative changes may be identified through computed tomography as well as magnetic resonance imaging, bone scan, and plain radiographs. Treatment modalities are based on the degree of symptomatic degenerative changes present. In early stages, steroid injection is used to diminish inflammation at the midtarsal joint. Typically, this is performed with orthotic therapy to limit the motion at the calcaneonavicular coalition. More advanced stages will require surgical intervention. Based on the degree of degeneration at the more proximal subtalar joint, arthroplasty of the calcaneonavicular coalition without interposition of the extensor digitorum brevis has produced acceptable long-term results. If the subtalar joint has advanced degeneration and there has been failure of more conservative treatments, rearfoot arthrodesis has been performed.

The extended lateral approach to the hindfoot. Anatomical basis and surgical implications

We have recently described an extended lateral approach to the hindfoot for the operative treatment of displaced intra-articular fractures of the calcaneum. It has the advantage of avoiding damage to the sural nerve and preserving blood supply to allow prompt healing. We dissected 15 formalin-preserved cadavers, taking photographs to show the structures of the posterolateral aspect of the hindfoot and ankle. We describe a superficial and a deep triangle: the deep triangle contains a constant posterior peroneal artery which supplies the skin of the posterolateral heel. An approach designed to expose the sural nerve will divide this important artery and cause ischaemia of the posterior skin. The extended lateral approach elevates the sural nerve in a thick flap and preserves the blood supply of the skin. We have reviewed 150 consecutive patients after the use of this approach to study the indications for operation, the quality of wound healing, any damage to the sural nerve and other complications. We recommend the careful use of this approach. Our understanding of its anatomical basis has allowed us to widen the indications for its use.

The sinus tarsi spacer in the operative treatment of flexible flat feet

The results of operative treatment of 45 flexible flat feet (29 patients) using the sinus tarsi spacer are reported. Although radiological improvement in both the talar declination and the ground-navicular distance was found, our patients suffered from pain and functional impairment for an average period of 5 months. An unacceptably high rate of spacer dislocation was noted. Furthermore, the literature indicates spontaneous improvement as the natural history of flexible flat feet. We therefore no longer advise the sinus tarsi spacer as a routine treatment for flexible flat feet.

Subtalar arthrodesis for posterior tibial tendon dysfunction and pes planus

Twenty-one patients (21 feet in 18 women and three men) who were treated with subtalar arthrodesis for posterior tibial tendon dysfunction and pes planus at an average age of 60 years (range, 44-75 years) were studied. Mean duration of symptoms was 3 years. All had realignment of the calcaneus in relation to the talus, and all had screw fixation without supplemental bone graft. Average followup was 3 years (range, 2-5 years). All patients had successful union. The tibiocalcaneal angle averaged 13 degrees +/- 3.1 degrees before operation and 6 degrees +/- 1.9 degrees after operation. The lateral talometatarsal, lateral talocalcaneal, and lateral tibiotalar angles all improved significantly. Arch height (navicular height) increase averaged 5 +/- 2.7 mm. Arch length (calcaneal-metatarsal) decrease averaged 4 +/- 3.2 mm. One complication occurred: delayed wound healing (excellent result). Clinical results were excellent in eight feet, good in eight, fair in four, and poor in one. Patients were satisfied with the operative result in 16 feet, satisfied with reservations in four, and dissatisfied with the operative results in one. Subtalar arthrodesis effectively corrects deformity, does not require bone graft, has a high union rate, and is associated with a low complication rate. However, 11 of the 21 patients continued to have some pain, and in patients with preexisting arthrosis of adjacent joints, symptoms may persist.

Microfoci of avascular necrosis in sickle cell anemia: pathophysiology of the dot dash pattern

OBJECTIVE

Definition of the nature of calcaneal "erosions" in sickle cell anemia.

METHODS

Skeletons of individuals demonstrated to have had sickle cell anemia were examined for the presence of calcaneal surface discontinuity.

RESULTS

Calcaneal and articular surface osseous microinfarction were identified macroscopically and confirmed radiologically by CT.

CONCLUSIONS

This appears to be the first macroscopic identification of calcaneal and articular surface osseous microinfarction in sickle cell anemia and explains the osseous pathology that appears so unique to sickle cell anemia.

Primary subacute haematogenous osteomyelitis of the tarsal bones in children

Primary subacute haematogenous osteomyelitis (PSHO) of the small bones of the foot is a rare and infrequently considered cause of a limp in children. We describe 11 patients with PSHO, of whom nine were under three years of age, who had a limp with few symptoms. The talus was involved in 36%. Bone scans were positive in all patients and led to localisation of the lesion in two. The radiological features included soft-tissue swelling, an osteolytic lesion in the talus and the calcaneus and a sclerotic appearance of the cuboid and the navicular bones. All patients except one were cured with antibiotics.

Ewing's sarcoma of the foot

The results of treatment were reviewed in 16 patients (10 male and six female) who had Ewing's sarcoma of the foot from 1954 through 1992. Mean age was 17 years (range, 10-42 years). The tumor involved the metatarsals (six patients), phalanges (four), calcaneus (three), navicular (one), talus (one), and calcaneus and phalanx (one). Seven patients had metastatic disease at the time of diagnosis, and only one of these patients survived. None of the patients with pulmonary metastasis at presentation survived. Nine patients had localized disease at the time of diagnosis, and eight survived. In the overall series, nine of the 16 patients were alive at followup (eight survived at least 5 years). Diagnosis was established at an average of 14 months from the onset of symptoms: 7 months in forefoot tumors and 22 months in hindfoot tumors. None of the six patients who had a resection had local failure. Seven of the 10 patients with forefoot lesions survived, and two of the six patients with hindfoot lesions survived. Treatment of Ewing's sarcoma of the foot by local control with radiation or operation and systemic control with chemotherapy is recommended. Survival appears to be better in patients who present with localized disease and forefoot lesions. Survival is worse in patients who present with metastatic disease. Surgical treatment appears to have an important role in local control and survival.

Rheumatoid nodules: MR/pathological correlation

PURPOSE

To demonstrate the signal characteristics of subcutaneous rheumatoid nodules in correlation to their histopathologic features.

METHOD

The magnetic resonance imaging (MRI) features of biopsy proven subcutaneous rheumatoid nodules are described in five patients with rheumatoid arthritis established by classic criteria.

RESULTS

Two morphologic appearances of rheumatoid nodules were observed on MRI: one predominantly cystic, with enhancing peripheral component; and a second type which is predominantly solid, with uniform enhancement following gadolinium injection.

CONCLUSION

Subcutaneous rheumatoid nodules can appear by MR as solid, cystic, or a combination of both components. This closely correlates with their histopathologic evolution.

[Ultrasonography of Achilles tendon lesions--an experimental study]

AIM

In an experimental study the accuracy of ultrasound in the detection of lesions of the achilles tendon was examined.

METHODS

60 Achilles tendons were examined post mortem macroscopically, histologically and by means of ultrascan.

RESULTS

All macroscopical changes were found in the sonograms. Especially changes of the form proved to be good diagnostic patterns for degenerative lesions of the tendon. At a distance of 2 cm proximal to the calcaneus histological changes could be detected with an accuracy of 73.3%. At 4 and 6 cm to the calcaneus we found similar results.

CONCLUSION

A differentiation of the histological diagnosis by means of the sonographic behaviour was not possible. As a reproducible, effective and inexpensive method ultrasound examination has proved very useful in the detection of degenerative lesions of the Achilles tendon.

Replacement of the lateral malleolus of the ankle joint with a reversed proximal fibular bone graft

Infrequently, prior reports have described the use of the ipsilateral proximal fibula to replace an absent distal fibula caused by either trauma, infection, or resection for tumor. This is a 27-year follow-up of a 12-year-old patient who lost the distal 7.5 cm of her fibula secondary to trauma. The soft tissue defect was replaced early by an abdominal flap and the bone defect was eventually replaced with 7.5 cm of proximal fibula. The lateral ankle ligaments were reconstructed with the peroneus brevis, and the ankle joint has remained stable. Although traumatic arthrosis has progressed slowly, the patient at age 39 has a relatively painless, mobile ankle joint.

Computed tomographic evaluation of calcaneal fractures

Computed tomography (CT) can be a useful adjunct to conventional radiographs in the evaluation and treatment planning of comminuted calcaneal fractures. Either a combination of direct coronal and axial scan planes or a single set of oblique images may be used to study the calcaneus. CT can show the fracture planes, including the amount of displacement of fracture lines entering the posterior subtalar facet and the relationship of the sustentaculum tali to the remainder of the bone. Evaluation of the calcaneocuboid joint and any widening that has occurred due to the fracture is also easily accomplished with CT. CT should be interpreted in conjunction with the conventional radiographs as rotational components and flattening of the Böhler angle may be appreciated better on them than on CT.

Achilles tendon insertion: an in vitro anatomic study

Seventeen adult fresh-frozen below-knee amputation cadaver specimens were studied. Calcific Achilles tendinitis was present in three specimens. After exposing the Achilles tendon insertion on the calcaneus, the insertion was outlined with waterproof paint. The specimens were photographed on a special plexiglass apparatus to highlight important findings. For the purpose of showing the length of insertion on lateral radiographs, lead beads were placed on the most superior and most inferior aspects of the insertion. All specimens showed that the tendon terminated at the medial and lateral bone borders of the calcaneus without significant extension around the medial or lateral wall. All specimens revealed a greater distance of insertion on the medial calcaneus than on the lateral side. In the specimens that had calcific Achilles tendinitis, the posterior bone surface of the spurs was devoid of tendinous insertion, instead, the insertion occurred between the spur and the posterior wall of the calcaneus. All spurs were located laterally at the most inferior border of the tendon insertion.

Avulsion fracture of the calcaneus: report of a case using a new tension band technique

We report a case of avulsion fracture of the calcaneus in an 83-year-old woman. Nonoperative treatment was not considered satisfactory. However, the os calcis was osteoporotic, and internal fixation therefore was performed with a transverse Kirschner pin through the os calcis, securing a figure-of-8 metal tension band wiring to the fragment. We suggest that this technique provides a strong internal fixation in selected cases.

Talocalcaneal coalition resection: a 10-year follow-up

Eight patients (nine feet) who underwent resection of persistently symptomatic talocalcaneal middle-facet coalitions were reevaluated > or = 10 years after surgery. Satisfactory results persisted in eight of nine cases with no deterioration of symptom relief. There was no loss of motion or development of degenerative joint changes. No patient required a secondary surgery. It appears that resection of symptomatic talocalcaneal coalition provides satisfactory results in the majority of patients, and its benefits are maintained 10 years after the procedure.

Intraosseous lipoma of the calcaneus

We present two patients with pathologically proven intraosseous lipoma of the os calcis. A review of the literature, the radiologic criteria, and the differential diagnosis are provided.

Chronic localized osteomyelitis caused by atypical infection with Blastomyces dermatitidis in a dog

A 4-year-old male Golden Retriever was evaluated because of chronic non-weight-bearing lameness of the right hind limb associated with penetrating tarsal wounds. Arthritis of the tarsal joint and osteomyelitis of the talus were initially evident. Tarsal arthrodesis was performed 7 months after initial injury, but the lameness persisted. Ten months later, blastomycosis was diagnosed on the basis of results of histologic examination of bone biopsy specimens and serologic tests. No other site of involvement was detected. The limb was amputated, and Blastomyces dermatitidis was isolated from the affected bone. Adjuvant antifungal treatment was not given. Ten months after amputation, the dog was in good health, and the antibody titer for B dermatitidis was low, indicating resolution of the infection. Localized bone infection with B dermatitidis is rare in dogs. In this dog, it was believed that blastomycosis was contracted through direct inoculation of the organism, because the lesion was associated with puncture wounds and other sites of involvement were not found.

The calcaneus: applications of magnetic resonance imaging

The calcaneus is the largest bone in the foot and is an important primary weightbearing structure. Pathologic processes that affect this bone may manifest in a variety of clinical presentations, including pain, abnormal motion, instability, or fracture. The purpose of this article is to present a pictorial essay of the wide spectrum of pathologic entities that may affect the calcaneus, emphasizing applications of magnetic resonance imaging and characteristic magnetic resonance features of these processes.

Sever's disease and other causes of heel pain in adolescents

Sever's disease, or apophysitis of the calcaneus, is a common but frequently undiagnosed source of heel pain in young athletes. This condition frequently occurs before or during the peak growth spurt in boys and girls, often shortly after they begin a new sport or season. Sever's disease often occurs in running and jumping sports, particularly soccer. Patients present with intermittent or continuous heel pain occurring with weight bearing. Findings include a positive squeeze test and tight heel cords. Sever's disease cannot be diagnosed radiographically. The condition usually resolves two weeks to two months after the initiation of conservative treatment, which may include rest, ice application, heel lifts, stretching and strengthening exercises, and, in more severe cases, nonsteroidal anti-inflammatory drugs.

Primary lymphoma of the calcaneus

Primary non-Hodgkin's lymphoma (NHL) of bone is a rare condition. Presented herein is a case of primary NHL of the calcaneus illustrating many of the classic features of the disease. Emphasized in this report are the nonspecific clinical and conventional radiographic features of primary NHL of bone, which may mimic inflammatory, neuropathic, infectious, or other neoplastic conditions of the extremities. The importance of early cross-sectional radiologic studies, such as magnetic resonance imaging, lies in the early characterization of the mass-like features and local extent of such lesions, helping to raise the suspicion of neoplastic disease.