authors: Dr Calvin CHIEN, MBBS, Dr Rajesh BEDI, DNB (Ortho), Dr Richard D. LAWSON, FRACS (Ortho). Case study of an adult with osteoporosis suffering a fracture.

1. Sunday, February 12, 2012
A Case Report: Treatment of a medial condylar humeral fracture in
an adult with osteopetrosis - (author: Calvin Chien)
Abstract:
Patients with osteopetrosis often present with orthopaedic
problems such as frequent fractures. Management of
fractures with open reduction and internal fixation is
difficult but possible. We report on a 22 year old patient
with a medial humeral condyle fracture treated
successfully with internal fixation using a pre-contoured
plate.
Introduction:
In 1904 Albers-Schoenberg described a condition characterised by marked radiographic density of the bones
(1). Despite the sclerotic radiographic appearance of the thickened cortices and its material hardness,
osteopetrotic bone is weak, brittle and prone to fracture after minor trauma (1). Most literature regarding
treatment of osteopetrotic patients with fractures concentrates on paediatric patients or on the difficulty of
operative intervention in adults (2). We report the case of an adult patient with osteopetrosis and a low
medial column fracture (Milch Type I (1)) of the distal humerus after minor trauma. The fracture was treated
operatively utilising internal fixation with a pre-contoured peri-articular plate.
Case:
A 22 year old female with known osteopetrosis presented
with an elbow injury after bracing herself with the right
arm after a fall. The mechanism described suggested a
valgus injury to the right elbow resulting in a Milch Type
I (3) low medial column fracture of the distal humerus
(Fig. 1). There were no neurological deficits. As an
adolescent she had previous injuries including one to the
radius of the same side limiting elbow extension by
twenty degrees. She was also partially blind and was
receiving psychiatric treatment for depression.
Two days later, open reduction of the right distal humerus was performed with internal fixation using a pre-
contoured medial condylar locking plate (Fig 2). This was done through a posterior approach after
identifying the ulnar nerve. Anterior transposition of the ulnar nerve was done before closure. The patient
was discharged two days later in a plaster-of-paris back slab with outpatient follow-up. After two weeks the
arm was placed in a range of movement elbow brace with unrestricted range of motion. Serial radiographs
were performed at four-weekly intervals and complete bony union with disappearance of the fracture line
was evident on the radiographs taken at fourteen weeks (Fig 3). Outpatient as well as a home-based
physiotherapy program was arranged and full pre-injury range of motion was achieved by ten weeks.
Discussion:
Osteopetrosis is a rare hereditary disease of the osteoclasts first described by Albers-Schönberg, a German
radiologist, in 1904. Defective osteoclastic activity or a reduced number of osteoclasts results in a failure of

2. bone remodelling (4). This is manifested on radiographs as an increase in bone mass and osteosclerotic
changes (4).
Osteopetrosis can be classified into three main forms: a malignant autosomal recessive, intermediate
autosomal recessive and benign autosomal dominant form; the vast majority of these cases are the benign
autosomal dominant form. The malignant autosomal recessive type, also known as infantile, is characterised
by growth retardation, failure to thrive and cranial nerve palsies manifesting as proptosis, deafness and
blindness. In addition, pancytopenia and thrombocytopenia may result from bone marrow failure. Many
features of the intermediate form of osteopetrosis are similar to those of the malignant form but the
intermediate form is less severe and later in onset. It is often diagnosed after a fracture, usually occurring in
the first decade. Benign osteopetrosis has been further subdivided into types I and II. However, recent genetic
studies have shown that autosomal-dominant osteopetrosis type I is caused by an increase in osteoblastic
activity rather than osteoclastic dysfunction. In this case osteoblasts deposit excessive amounts of bone
matrix (4). Type II autosomal dominant osteopetrosis is the form Albers-Schönberg first described and so is
often named after him. The onset is in later childhood and is usually diagnosed incidentally during a
radiographic examination (4). It is also associated with increased fracture frequency. Other manifestations
include coxa vara, osteoarthritis, spondylolysis, back pain, osteomyelitis and cranial nerve palsies.
Radiographic features include skull-base thickening, vertebral end-plate thickening and endobone appearance
(4).
Isolated medial condylar fractures of the humerus in adults are uncommon and we have not discovered a
report of this fracture in an osteopetrotic patient. Medial condylar fractures are intra-articular and like lateral
condylar fractures are prone to non-union (1). Usually, the mechanism for this fracture is through a valgus
force on an extended elbow where the force is transmitted via the olecranon or coronoid process into the
medial condyle (3). The fracture can also arise from an avulsion injury of the condyle through forceful
contraction of the forearm flexors. With minimally displaced fractures of the medial humeral condyle, good
fracture healing and functional outcomes can be expected with non-surgical treatment consisting of
immobilisation in a splint and a gradually increasing permissible range of motion (7). On the other hand,
studies specifically examining displaced medial humeral condylar fractures treated by open reduction internal
fixation reported good or excellent outcome in 86% of patients (2). As mentioned earlier, patients with
osteopetrosis are prone to infections and the reported incidence of post-operative infection is 12% (2).
Furthermore, some authors have reported delayed and non-union following fractures in osteopetrotic patients
(2). A study has shown fracture healing time in osteopetrotic mice to be more than twice as long (2).
Despite the difficulties of surgery, the risk of infection, and the higher incidence of delayed and non-union,
the patient achieved an excellent functional outcome with no surgical complications. Open reduction and
internal fixation to a fractured medial humeral condyle in a young osteopetrotic patient is certainly an option.
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Medical Journal.
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