Injury (1990) 21, 97-400 printed in Great Britain 97

A thorny problem: the diagnosis and treatment of acacia thorn injuries

Raju Vaishya G.R. Medical College Hospital, Gwalior, India

Immediate diagnosis and surgical tr&ment of acacia thorn inju y results in complete cure. Delay or late presentation results in morbidity. The features of this disorder are presented in a series of 22 patients. The principles of treatment can be applied to all other types of thorn injury.

Introduction

Penetrating injuries to the hand and foot by foreign bodies such as needles are common. Usually they are removed immediately and there is little morbidity. Indeed, attempts to remove them surgically can be very difficult and do more damage than if they had been left alone. This is not true of plant thorn injuries such as blackthorn or acacia thorn. Embedded thorns have been reported to cause bone lesions resembling those of osteomyelitis (Rosenfield et al., 1978). Maylahn (1952) observed that the organic material when present in or near a bone can produce a pathological reaction, either osteolytic (Figtlre I), osteoblastic (Figure2) or a combination of both (Figtrre3), the radiographic appear- ance of which may resemble a bone tumour. The diagnosis, given the history, is easy. In late cases the diagnosis can be difficult. If treated early and by surgery, acacia thorn injuries will cause no serious sequel.

Material

A series of 22 consecutive patients with Acacia arabica thorn injuries were treated (Table I). Sixteen attended for follow- up. There were 18 male patients, aged between 2 and 60 years; nine were schoolchildren. All the patients gave a history of a penetrating injury by an acacia thorn. Half the patients removed the thorn immediately (Figrrre4). Five patients removed the thorn within I week. Six patients were unable to remove the thorn and all of these developed osteomyelitis. The sites of injury were the foot (14), hand (5) and knee (3). Only half (II) presented within I week of injury. The others presented within 4 months (8), 4-12 months (2) and after 2 years (1); all had pain and swelling. Twelve had a visible puncture site. Four patients had obvious sinuses. The three patients who had thorns in their knees had a fixed flexion deformity, an effusion and synovial hypertrophy. Only one patient had a fever. The white cell count and erythrocyte sedimentation rate were unhelpful. Synovial fluid culture was sterile in all the knee cases. The

0 1990 Butterworth & Co (Publishers) Ltd 002O-1383/90/020097+4

plain radiographs did not show any foreign bodies but showed features consistent with a chronic osteomyelitis in six cases (Table II).

Figure 1. An osteolytic lesion in the base of the 2nd metatarsal.

98 Injury: the British Journal of Accident Surgery (1990) Vol. 2l/No. 2

Figure 2. A predominantly osteoblastic reaction in the shaft of the 2nd metatarsal.

Figure 3. A mixed osteoblastic and osteolytic reaction in the 4th metatarasal with a surrounding soft tissue swelling.

Total patients (22)

\

Immediately T,h;)m removed L ;;ylved)

L Afteran -

Not removed (Osteomyelitis) -surgery (6)

\ (Synovitis) After 24 hours

- surgery (4)

Within 24 hours (Resolved) (1)

Figure 4. Details of thorn prick and removal.

Vaishya: Diagnosis and treatment of Acacia thorn injuries 99

Table I. Clinical presentation of the patients

Clinical presentation Number of cases

Osteomyelitis (a) without adjacent joint involvement (b) with adjacent joint involvement

Soft tissue reaction Chronic mono-articular synovitis

(a) without articular surface involvement (b) with articular surface involvement

r i; 11

(53) (2)

Table II. Radiographic findings

Radiographic findings

Soft tissue swelling Rarefaction Osteolytic lesion Osteoblastic reaction Foreign body

Number of cases

18 10

7 4 0

Treatment

Ten patients consented to surgery. Embedded thorns were found in six patients. In all the cases a gross fibrosis was found at the site of injury. The affected site was explored and all the abnormal tissue was excised. In all the cases histopathological diagnosis was of a chronic non-specific inflammation (Fi&ure 5). In infected cases the wounds were explored and left open to heal by granulation. The 12 patients who refused operation were treated by antibiotics and splintage.

Results

Eight patients who had been treated surgically and eight patients who had been treated conservatively attended for review. The surgically treated patients had no further inflammation; the sinuses had healed and the disease had been cured. The conservatively treated group still had intermittent pain and swelling.

Discussion

The acacia plant (Acacia arabica) (Figure 6) grows in tropical climates. The tree is formidably armed with thorns 50-75 mm long which are hard and pungent (Chittenden, 1951). The false acacia plant (Robinia psardoauzcia) grows in more temperate countries such as England. Acacia thorn injury is common in India where children do not always wear shoes and it is unusual to wear strong shoes that would give the necessary protection in such heat. There is a trend for these injuries to affect children (Gerle, 1971; Dickson and Kemp, 1976) and perhaps because the connective tissues in children are supple the thorns are more likely to come to rest against the bones (Yousefzadeh and Jackson, 1978).

Late presentation after injury was the norm in this series. There is a period after injury when there are few symptoms. Patients apply simple remedies for what would appear to be a simple problem. Most acacia thorn injuries resolve spontaneously after the thorn is removed. It is not surprising that many patients are unaware of the potential dangers of acacia thorn injuries. The persistence of signs and symptoms is attributed to the fact that it is extremely difficult to extract

Figure 5. A chronic non-specific inflammatory reaction.

Figure 6. The acacia plant with 3 cm long thorns.

100 Injury: the British Journal of Accident Surgery (1990) Vol. 21/No. 2

the complete thorn; the tip or fragments of the tip remain in sifu (Kelly, 1966).

I am also grateful to Mr D. C. Jaffray for his help in preparing the manuscript.

Nearly all the patients will give the diagnosis if a history is taken. This is all that the clinician needs (Surgam et al., 1977). Examination does not add to but merely confirms the diagnosis. Blood tests are superfluous. The diagnosis should be made before radiographs are taken because the appear- ances of the radiographs can alarm the unwary clinician. The radiographs can reveal a picture that can be confused with other infections such as tuberculosis. There may be a real difficulty in excluding a neoplasm (Gerle, 1971).

Treatment must always be surgical if an early resolution is to be achieved. A wide exposure may be required because limb movement may have caused migration of the thorn (Maylahn, 1952). The thorn, together with surrounding inflamed tissue should be excised. Sometimes a small piece cannot easily be found at operation. No attempt should be made to find a needle in a haystack. The wound is left open to granulate and the limb is splinted. Adjuvant antibiotics may be given but they must not substitute a proper wound excision. With established osteomyelitis, however, it may be necessary to continue with antibiotics for a longer period. With this programme of treatment the disease process is halted. We rely on the support of the physiotherapists to restore as much function as possible. Those cases treated non-operatively perhaps resolve with time. They face a prolonged period of disability and more morbidity.

References

Chittenden F. J. (ed.) (1951) Acacia arabica. RoyaZ Horfimlfa4ral Sociefy: Dicfionay of Gardening. Vol. I. Oxford: Clarendon Press, 10.

Dickson R. D. and Kemp F. H. (1976) Thorn induced granuloma of bone. Hand. 8,69.

Gerle R. D. (1971) Thorn induced pseudoturnours of bone. Br. J. RadioI. 44, 642.

Kelly J. J. (1966) Black thorn infJammation. 1. Bone Joint Surg. 43B, 474.

Maylahn D. H. (1952) Thorn induced ‘tumours’ of bone. 1. BOW Joint Surg. 34A, 486.

Rosenfield R. et al. (1978) Thorn induced periosteitis associated with Enferobacfer agglomeram infection. Can. Med. Assoc. 1. 119, 925.

Surgam M. et al. (1977) Plant thorn synovitis. Arfhrifis Rkeum. 20, 1125.

Yousefzadeh D. K. and Jackson J. H. (1978) Organic foreign body reaction. Skeletal Radial. 3, 167.

Acacia thorn injuries provide a useful model for the clinician dealing with any thorn injury. Diagnosis is easy if a history is taken but is difficult otherwise. What may appear to be a minor injury can produce distressing morbidity. Resolution can be achieved early if adequate early surgery is performed.

Paper accepted 17 July 1989.

Acknowledgements

My sincere thanks to Professor B. Das and Doctor V. P. Middha for helping me to conduct this study.

Requests for reprhfs shouti be addressed to: R. Vaishya, c/o Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, UK.