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 Orthogate arrow Orthopaedic Rare Conditions Database (ORCID)
Royal Inland Hospital Poster PEOO6
AAOS 2000

ORCID
An Internet Database for the Management of Rare Conditions
A Member of the Thompson Health Region
British Columbia, Canada
Summary Purpose Rare Conditions Site Description Example
Results Discussion Take-Aways ORCID Site Orthogate

An Example

Articular Aspergilosis (Cactus Knee)

A 14 year old Canadian boy presented 24th March 1999 with inability to straighten his left knee. 3 weeks previously while on holiday in Mexico he had fallen against a cactus which had punctured his knee in three places on the superolateral aspect. He was reasonably sure that no spines had broken off. He was able to continue walking though his knee swelled and hurt. He attributed that to "poison" on the spines.

5 days before presentation his knee locked. He was able to flex quite well and could still walk but had a flexion deformity of 40 degrees. On examination he was afebrile, the puncture wounds had healed without inflammation, he had an effusion, wasting of the quadriceps and painful locking with the pain being at the medial joint line. Xrays of the left knee were normal. He was admitted on suspicion of a medial meniscus injury. Because of the possibility of infection he was operated on urgently.

cactus1.jpg (12742 bytes)  

 

At arthroscopy a cactus spine, about 2 cms long and 2mm in diameter was found.

It had broken off from the entry point in the suprapatellar region, floated round the knee then impaled itself into the medial meniscus. There was some blood-stained, slightly turbid fluid which was sent for culture. This  grew Aspergillus.
cactus2.jpg (12533 bytes)  

 

I retrieved the spine. There was none of the purulent exudate typical of an infected knee, although there was some hyperaemia of the synovium. Suction/irrigation drains were placed and 200cc saline /hour with 1 gram of Cefazolin per 3000cc was irrigated through his knee for 24 hours. He was also placed on IV Cefazolin pending cultures.

In the lateral wall of the suprapatellar pouch the entry point of the spine could be distinguished. There was a small puncture wound with fibrinous clot hanging down from it. The spine is shown just prior to removal. It had been impaled into the meniscus seen to the left and had to be withdrawn into the joint to free it up. A pituitary rongeur holding the blunt end of the spine is seen in the top of the picture.

Over the next 4 days he was afebrile and comfortable, taking no analgesics and wanting to go home. The drains were removed after 48 hours. On 29th March the infectious disease consultant told me they have cultured aspergillus from the fluid. He advised against antifungal agents (Amphotericin) as he thought the patient would clear it up himself now that the contaminating spine was removed. He was discharged with review in 2 weeks at which time repeat aspiration of the knee and fungal culture was planned if there was an effusion.

2 weeks later he was reviewed in the orthopaedic clinic. He had 1 cm wasting of the quadriceps and a very small synovial effusion. There is full range flexion and about 5 degrees quads lag. He was non-tender. Considering the length of time he was symptomatic pre-op and the period of irrigation I felt his knee showed no signs of on-going infection or chronic synovitis. The aspiration was not repeated. He undertook a physiotherapy rehabilitation programme and at 3 month follow-up he was asymptomatic and had normal examination and function.

This case is the first documented case of articular aspergillosis in a patient without immune compromise. There are cases in immune suppressed and diabetic patients. Thorn synovitis is a well known entity but has not previously been ascribed to aspergillus.

Comments attracted by this case

1. A number of the cases of thorn synovitis present as chronic synovitis. The original puncture injury may be forgotten. Bear this possibility in mind when faced with a monoarthritis.

2. Complete synovectomy may be required and simple removal of the thorn may not be enough in chronic cases.

3. The largest collection of cases published was 20 from India. However, some of the Orthopod Mailing List members suggest that thorn synovitis is quite common.

4. The bacteriology is very varied with no organism predominating. Dr Lou from Malaysia suggested that Staph aureus was common but only because most of the patients had tried to dig the thorn out themselves and got a secondary infection. I'm not sure if the consensus is that the synovitis is of microbial aetiology or is a hypersensitivity reaction to the foreign body.

5. CT scan was recommended where this diagnosis is suspected as it is much more likely to demonstrate the presence of an intra-articular thorn than plain xrays. There is one report of MR scanning showing up the object really well.

 

49 references to articular aspergillosis and thorn synovitis were found.

 
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