Key Words

avulsion fracture, calcaneal tuberosity, treatment

Introduction

Calcaneal tuberosity Avulsion fractures are relatively uncommon extra -articular injury. This type of fracture accounts about1.3% to 2.7% of calcaneum fracture [1]; they usually caused by forced ankle dorsiflexion; other fractures are due to sudden concentric contraction of the gastrocnemius-soleus with simultaneous extension of the knee[2] ,such risk factors have been reported as Osteoporosis ,ostopenia, Neuropathic disorders Metabolic diseases [3]. The fracture must be reduced and fixed urgently to avoid skin complications and the choice of technique depends on the size of the avulsed bone fragment and the quality of bone

Presentation of Cases

Case n ° 1

A 40 year old male patient sustained a fall during a sporting exercise; the position of ankle was in forced dorsiflexion; he presented with pain and swelling of right ankle, on examination; the movement of ankle are painful and restricted; with loss of plantar flexion power. ; The imagery shows avulsion fracture of the calcaneal tuberosity Figure 1 the patient treated by open reduction of small bone fragment which is introduced and secured in a tunnel drilled through the calcanum. And fixed by screw of interference followed by a plaster immobilization for 6 weeks associated with functional rehabilitation

Case n° 2

A 50 year old male patient ; diabetic; sustained a left ankle closed injury following a fall, when climbing stairs, one week prior to presentation . The patient reported immediate pain and restricted movement of the left ankle. . On physical examination, there was mild swelling of the left ankle, with proeminence of the heel and plantar flexion deficit The radiographs revealed avulsion fracture or ‘sleeve’ type tuberosity fracture. Figure 2 The patient treated by open reduction of avulsed fragment and fixation by anchors suture. Followed by Immobilisation in short-leg equinus cast for a period of six weeks followed by functional rehabilitation.

Results

On review at 6 months post-operatively. Fracture was consolidated in both cases with absence of pain in walking; and the plantar flexion power is similar to that of the contralateral ankle; otherwise problems with redisplacement or wound-healing were not seen

Figure 1: Pre-operative and post operative radiographs of infrabursal avulsion involving superficial fibers of Achilles tendon (type3 Beavis et al)

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Figure 2: Pre-operative and post operative radiographs of a fracture of posterior calcaneal tuberosity.(type 1 Beavis et al)

Discussion

Avulsion fractures of the calcaneal tuberosity are rare occurrence injuries. The incidence reported for these particular fractures in the literature range between1.3% to 2.7% of all calcaneal fractures 1. A high rate was observed in older women because of diminished bone density 4 Most of these injuries are a result of indirect trauma produced by falls causing sudden forced dorsiflexion; with pull of Achilles tendon; the forces transmitted mainly via Achilles tendon to calcaneal tuberosity causing avulsion of a fragment of bone. Avulsion fracture of the tuberosity of the calcaneum has been previously described by malgaine in 1843 5 According to the literature 6, tuberosity avulsions were classified into two types; those that do not involve the insertion of the Achilles tendon and those that do involve the insertion of the Achilles. Beavis and al 7 modified this classification through addition of an another avulsion type 3 in which there is an infrabursal avulsion involving superficial fibers of Achilles tendon Management and treatment is often dependent on many factors as the age, type of avulsion; the size of avulsed fragment; quality of bone; and functional demands of the patient 2 Though Prothere 8stated that the operative correction is an emergency because of the risk of pressure necrosis of skin overlying displaced fragments and the Achilles tendon Non operative treatment is done by closed reduction followed by an immobilization. In a short-leg non weight bearing equinus cast for 6 to 12 weeks; the reduction is achieved by simultaneous flexion knee and the ankle, with pushing the displaced fragment. Such complications have been reported after non operative treatment as redisplacement, nonunion and loss of plantar flexion power 9. For these reasons; many authors recommend treatment with open reduction and internal fixation 10. Various Methods of fixation include suturing of the avulsed bone fragment, suture anchors, tension band wiring and screw fixation 2 In contrast to the other techniques, the use of suture anchors or interference screw was technically simple and these repair agents are elegant solution since they are thrusted into the bone; therefore they don’t cause a pressure of the thin skin at the back of the heel. And the two patients treated operatively using these techniques of fixation, had a good final outcome;.

Conclusion

These are rare and infrequent injuries. Which should be treated as an emergency to avoid complications; the outcome is dependent on the method of treatment and presence of risk factors. Two of our cases, had a successful outcome. We therefore recommend internal fixation using the suture anchors or interference screw we found this technique simple and easy to perform without the fear of damaging the skin of posterior heel.