Hegemann Disease

Hegemann disease is osteochondrosis of the humeral trochlea, similar to Panner disease, but much less common. Patients are typically between the ages of 7–13 years, and present with swelling and restricted range of motion

Radiographs reveal rarefaction of the ossification center of the trochlea with condensation and collapse. Because the trochlea has a multicentric, irregular, and granular ossification center compared to the capitulum, comparison views and radiographic follow-up should be used to distinguish normal variants of ossification from Hegemann disease.

The main differential consideration is osteochondritis dissecans, which tends to affect older patients (12-15 years, around the time of epiphyseal plate ossification), does not affect the entire ossification center (only the subchondral bone), and is not a self-limited process. Chondroblastoma is also a consideration, as it tends to affect the epiphysis.

References

Patel N, Weiner SD. Osteochondritis dissecans involving the trochlea: report of two patients (three elbows) and review of the literature. J Pediatr Orthop. 2002 Jan-Feb;22(1):48-51.

Panner Disease

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Osteochondrosis refers to injuries to the epiphyses, physes, and apophyses of children that occur because of a disturbance of epiphyseal growth during childhood. This results in necrosis in the subchondral bone and adjacent epiphyseal cartilage. Most osteochondroses are self-limiting.

Panner disease is an osteochondrosis characterized by necrosis of the capitular ossification center and is a cause of lateral elbow pain in children. It is thought to be due to compromise of the blood supply to the capitular ossification center due to valgus stress, and is a self-limiting process, with restoration of the normal morphology of the capitulum.

It usually occurs in the dominant elbow in children, usually boys, between the ages of 7 and 12 years. Patients present with insidious-onset dull ache and swelling over the lateral elbow. The pain is typically aggravated by activity and relieved by rest. Treatment is usually conservative and includes avoidance of activities that stress the radiocapitular joint.

Radiography reveals areas of demineralization or sclerosis, usually involving the entire ossific nucleus of the capitulum. Fragmentation of the ossification center may or may not be present.

MRI is used to assess the integrity of the overlying cartilage and to look for intra-articular fragments, but is generally not needed for diagnosis. However, MRI can reveal radiographically occult abnormalities early in the course of disease. The typical appearance is signal abnormality in the capitulum with intact overlying cartilage.

The main differential consideration is osteochondritis dissecans of the elbow, which tends to affect older patients (12-15 years, around the time of epiphyseal plate ossification), does not affect the entire ossific nucleus of the capitulum, and is not a self-limited process. Chondroblastoma is also a consideration, as it tends to affect the epiphysis.

Panner disease and osteochondritis dissecans are now thought to represent a continuum of abnormal endochondral ossification, with presentation and prognosis depending on the age of onset.

References

• Doyle SM, Monahan A. Osteochondroses: a clinical review for the pediatrician. Curr Opin Pediatr. 2010 Feb;22(1):41-6.
• Kotnis NA, Chiavaras MM, Harish S. Lateral epicondylitis and beyond: imaging of lateral elbow pain with clinical-radiologic correlation. Skeletal Radiol. 2012 Apr;41(4):369-86. Epub 2011 Dec 30.

Coracoid Fractures

Fractures of the coracoid process are uncommon injuries that can be caused by direct trauma or avulsion. Avulsion fractures can be at the attachment of the coracoclavicular ligaments in the setting of acromioclavicular dislocation or at the muscular attachments in the setting of violent contraction. They can also occur in association with clavicular fractures and shoulder dislocation and can impede reduction in the latter.

Complications of coracoid fractures include hemorrhage into the muscles of the rotator cuff and damage to the suprascapular nerve.

Coracoid fractures have been classified into 5 types based on the location of the fracture plane:

• Type 1: Involve the tip (epiphyseal fracture)
• Type 2: Through the midportion.
• Type 3: Through the base (basal fracture). Most common.
• Type 4: Extend to the superior body of the scapula.
• Type 5: Extend into the glenoid fossa.

Each can be further subdivided into A and B classifications based on the absence or presence of damage to the clavicle or its ligamentous connections to the scapula.

Management is usually conservative for types 1-3. Internal fixation is often recommended for types 4 and 5.

A simpler classification divides them into two types based on the relationship of the fracture to the coracoclavicular ligaments: Type-I fractures are proximal to this attachment and can disrupt the scapuloclavicular connection. Type-II fractures are distal to the coracoclavicular ligaments. Type I fractures often require internal fixation, while type II fractures can be managed conservatively.

The image above shows a type 2 fracture. The anteroposterior view reveals a double contour of the coracoid process (pink arrow), suggestive of displacement and early callus formation. The axillary view shows the fracture plane (white arrows) through the midportion of the coracoid process.

References

• Eyres KS, Brooks A, Stanley D. Fractures of the coracoid process. J Bone Joint Surg Br. 1995 May;77(3):425-8.
• Ogawa K, Yoshida A, Takahashi M, Ui M. Fractures of the coracoid process. J Bone Joint Surg Br. 1997 Jan;79(1):17-9.

Crimp Sleeve

Crimp sleeves (white arrows) are devices for connecting wires or cables. They are used in fishing, manufacturing, and orthopedics. Surgical cable and crimp systems are used to secure bone fragments under pressure, providing better fixation than simple twisting of cerclage wires. The wire ends pass through the crimp sleeve and are deformed by a crimping device to secure the wires in place.

Patterns of Vertebral Ossification in Paralyzed Patients

Four patterns of vertebral ossification abnormalities can be seen in paraplegic and quadriplegic patients. These resemble osteophytes, syndesmophytes, irregular paraspinal ossifications, and flowing ossifications.

• Osteophytes: Originate near the superior and inferior margins of the vertebral bodies.
• Paraspinal ossifications: Irregular, asymmetric ossification affecting paravertebral soft tissues with an appearance similar to that of psoriasis.
• Syndesmophytes: Thin areas of ossification with a symmetric vertical orientation in the outer portions of the annulus fibrosus, mimicking ankylosing spondylitis.
• Flowing ossifications: Similar to those seen with diffuse idiopathic skeletal hyperostosis (DISH). Seen in 3% of quadriplegic and 1% of paraplegic patients (may not be significantly higher than that found in the general population).

The frequency of vertebral ossification seems to be depend on age and duration of paralysis in both quadriplegic and paraplegic patients. The image above is from a patient with spinal cord injury. We see paravertebral ossifications at T3-T4 and T4-T5 with preserved disc spaces. The appearance at T3-T4 is more akin to an osteophyte, while the appearance at T4-T5 is closer to a syndesmophyte.

References

• Park YH, Huang GS, Taylor JA, Marcelis S, Kramer J, Pathria MN, Clopton P, Resnick D. Patterns of vertebral ossification and pelvic abnormalities in paralysis: a study of 200 patients. Radiology. 1993 Aug;188(2):561-5.
• Killebrew K, Gold RH, Sholkoff SD. Psoriatic spondylitis. Radiology. 1973 Jul;108(1):9-16.

Agility Total Ankle Arthroplasty

Continuing an earlier discussion on the INBONE ankle arthroplasty, we'll talk briefly about the Agility total ankle arthroplasty, the oldest and most commonly used system in the United States. It has undergone several modifications since initial FDA approval in 1992, but the essential design is a semiconstrained two-component device with a polyethylene disc.

It is important to evaluate follow-up radiographs for periprosthetic lucency, lysis, and component migration or subsidence. Subsidence at the talus is especially important to detect early. The case above is from a bone survey, so we don't have a lateral view, but there is suggestion of talar subsidence on the frontal view.

Because it is the oldest system in use, long term follow-up data are available for the Agility, and the majority don't seem to be good. A recent study of 41 patients with the Agility, for example, found that almost 40% needed revision surgery at some point (follow-up period of 6 months to 11 years), with an average time to revision surgery of 4 years. In addition, the authors found that patients without revisions reported only moderate pain relief and function.

A systematic review of all ankle arthroplasties found that revision rates published in clinical studies were about half the value found in registries, possibly because of the over-representation of publications by implant developers (almost 50% of the published content), who tended to report better results.

References

• Criswell BJ, Douglas K, Naik R, Thomson AB. High Revision and Reoperation Rates Using the Agility(TM) Total Ankle System. Clin Orthop Relat Res. 2012 Jan 24.
• Kopp FJ, Patel MM, Deland JT, O'Malley MJ. Total ankle arthroplasty with the Agility prosthesis: clinical and radiographic evaluation. Foot Ankle Int. 2006 Feb;27(2):97-103.
• Labek G, Klaus H, Schlichtherle R, Williams A, Agreiter M. Revision rates after total ankle arthroplasty in sample-based clinical studies and national registries. Foot Ankle Int. 2011 Aug;32(8):740-5.

Foreign Body

Telephone handset in rectum
Cocaine bags in colon

Foreign bodies are uncommon, but they are important and interesting. Foreign bodies may be ingested, inserted into a body cavity, or deposited into the body by a traumatic or iatrogenic injury.

Foreign body ingestions or insertions are seen in four broad categories of patients:

• Children
• Mentally handicapped persons. May present multiple times for unusual injuries and foreign body insertions and ingestions.
• Adults with unusual sexual behaviors
• "Normal" adults or children with predisposing factors or injurious situational problems. This group includes individuals who may abuse drugs or alcohol, engage in criminal activities, engage in extreme sporting activities, or may be subject to child or spousal abuse.

The rectum, vagina, urethra, nose, and ear are favorite sites for insertion of foreign objects.

References

• Hunter TB, Taljanovic MS. Foreign bodies. Radiographics. 2003 May-Jun;23(3):731-57.
• Rolando Reyna, mypacs.net