4
Received: 12 August 1999 Revision requested: 31 October 1999 Revision received: 1 May 2000 Accepted: 11 May 2000 Abstract We describe a case of plant-thorn synovitis of the elbow resulting from a thorn injury. This caused recurrent pain and swelling of the elbow over a 3-month period. A magnetic resonance imaging ex- amination was initially requested to exclude septic arthritis, and demon- strated a joint effusion, synovitis, and a 2-cm linear opacity embedded in the synovium. Ultrasound was performed prior to surgery to con- firm these findings and provide ac- curate localization of the thorn frag- ment, later removed at surgery. To our knowledge this is the first exam- ple of this condition that has been confirmed by radiological imaging prior to surgery. Keywords Plant-thorn synovitis · Monoarticular arthritis · Elbow · Magnetic resonance imaging · Ultrasound · Power Doppler Skeletal Radiol (2000) 29:605–608 © International Skeletal Society 2000 CASE REPORT K.J. Stevens T. Theologis E.G. McNally Imaging of plant-thorn synovitis Introduction Plant-thorn synovitis is one of the causes of a monoarticular arthropa- thy [1, 2, 3, 4, 5]. This occurs when a thorn punctures a joint and sets off a foreign body reaction, resulting in a chronic relapsing arthritis. Symp- toms may occur long after the thorn injury has been forgotten, and in the absence of a comprehensive history, the aetiology may remain unknown until the thorn is found during syno- vectomy. We present a case of plant- thorn synovitis where the thorn frag- ment was demonstrated on magnetic resonance imaging (MRI) examina- tion and ultrasound, both confirming the diagnosis and providing accurate localization of the thorn fragment prior to surgery. Case report An 11-year-old boy presented with recurrent pain and swelling of his left elbow. Three months prior to this he had fallen, sustaining a penetrat- ing wound to the lateral aspect of his elbow. His mother removed the of- fending thorn, but the elbow soon became swollen and painful. He was treated with antibiotics for a pre- sumed infection, but did not have a serological diagnosis at the time. Al- though the joint initially settled, the elbow continued swelling inter- mittently, associated with pain and malaise. Examination demonstrated a swol- len and tender joint, with reduced range of flexion and extension. Pro- nation and supination were unaffect- ed. Antero-posterior and lateral radiographs showed the presence of a large elbow joint effusion, but did not demonstrate any radio-opaque foreign body. Blood tests revealed a normal white cell count, but a raised C-reactive protein level of 33 mg/l. A diagnosis of chronic septic ar- thritis was postulated, and an urgent MRI scan was requested to exclude K.J. Stevens, FRCR · E.G. McNally, FRCR Department of Radiology, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford, OX3 7LD, UK T. Theologis, MD Department of Orthopaedic Surgery, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford, OX3 7LD, UK K. Stevens ( ) Department of Radiology, Stanford University Medical Centre, Grant Building, Room S-062, 300 Pasteur Drive, Stanford, CA 94305-5105, USA

Imaging of plant-thorn synovitis

Embed Size (px)

Citation preview

Page 1: Imaging of plant-thorn synovitis

Received: 12 August 1999Revision requested: 31 October 1999Revision received: 1 May 2000Accepted: 11 May 2000

Abstract We describe a case ofplant-thorn synovitis of the elbow resulting from a thorn injury. Thiscaused recurrent pain and swellingof the elbow over a 3-month period.A magnetic resonance imaging ex-amination was initially requested toexclude septic arthritis, and demon-strated a joint effusion, synovitis,and a 2-cm linear opacity embeddedin the synovium. Ultrasound wasperformed prior to surgery to con-firm these findings and provide ac-curate localization of the thorn frag-ment, later removed at surgery. Toour knowledge this is the first exam-ple of this condition that has beenconfirmed by radiological imagingprior to surgery.

Keywords Plant-thorn synovitis · Monoarticular arthritis · Elbow ·Magnetic resonance imaging · Ultrasound · Power Doppler

Skeletal Radiol (2000) 29:605–608© International Skeletal Society 2000 C A S E R E P O RT

K.J. StevensT. TheologisE.G. McNally

Imaging of plant-thorn synovitis

Introduction

Plant-thorn synovitis is one of thecauses of a monoarticular arthropa-thy [1, 2, 3, 4, 5]. This occurs whena thorn punctures a joint and sets offa foreign body reaction, resulting ina chronic relapsing arthritis. Symp-toms may occur long after the thorninjury has been forgotten, and in theabsence of a comprehensive history,the aetiology may remain unknownuntil the thorn is found during syno-vectomy. We present a case of plant-thorn synovitis where the thorn frag-ment was demonstrated on magneticresonance imaging (MRI) examina-tion and ultrasound, both confirming

the diagnosis and providing accuratelocalization of the thorn fragmentprior to surgery.

Case report

An 11-year-old boy presented withrecurrent pain and swelling of hisleft elbow. Three months prior to thishe had fallen, sustaining a penetrat-ing wound to the lateral aspect of hiselbow. His mother removed the of-fending thorn, but the elbow soonbecame swollen and painful. He wastreated with antibiotics for a pre-sumed infection, but did not have aserological diagnosis at the time. Al-

though the joint initially settled, the elbow continued swelling inter-mittently, associated with pain andmalaise.

Examination demonstrated a swol-len and tender joint, with reducedrange of flexion and extension. Pro-nation and supination were unaffect-ed. Antero-posterior and lateral radiographs showed the presence of a large elbow joint effusion, but did notdemonstrate any radio-opaque foreignbody. Blood tests revealed a normalwhite cell count, but a raised C-reactive protein level of 33 mg/l.

A diagnosis of chronic septic ar-thritis was postulated, and an urgentMRI scan was requested to exclude

K.J. Stevens, FRCR · E.G. McNally, FRCRDepartment of Radiology, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford, OX3 7LD, UK

T. Theologis, MDDepartment of Orthopaedic Surgery, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford, OX3 7LD, UK

K. Stevens (✉ )Department of Radiology, Stanford University Medical Centre, Grant Building, Room S-062, 300 Pasteur Drive, Stanford, CA 94305-5105, USA

Page 2: Imaging of plant-thorn synovitis

performed using an ATL 5000 machine (HDI 5000, AdvancedTechnology Laboratories, Seattle,WA) with a 5–12 MHz variable-frequency linear-array probe, withscanning in multiple planes, con-firming the presence of synovitis and

606

a joint effusion. Ultrasound alsoshowed a 2-cm linear hyperechoicstructure, lying anterolateral to thecoronoid fossa (Fig. 2). PowerDoppler showed increased synovialperfusion around the thorn consistentwith an inflammatory response.

Fig. 1 Axial TSE T2-weighted (A)and coronal STIR (B) images showing a 2-cmlinear thorn fragment within the anteriorjoint (filled arrow), with associated syno-vial hypertrophy (curved arrow) and jointeffusion (open arrow)

Fig. 2 Axial ultrasound image (A) demon-strating a 2-cm linear foreign body (mark-ers) within the anterior aspect of the joint,with surrounding inflammatory changewithin the synovium (open arrow) on pow-er Doppler (B)

Fig. 3 Photograph of the thorn fragmentremoved at surgery. The scale marker rep-resents 1 cm

associated osteomyelitis or subperiosteal collections, whichwould alter surgical management.Coronal STIR and T1-weighted im-ages, and axial T2-weighted images,were obtained in a 1-T Siemens Expert scanner (Siemens, Erlangen,Germany). This demonstrated floridsynovitis and a large joint effusion.A linear structure measuring approximately 2 cm was seen in theanterior aspect of the joint on coro-nal and axial T2-weighted images,felt to represent a large fragment ofthorn (Fig. 1). Prior to surgery, an ultrasound examination was re-quested to ascertain the anatomicalposition of the thorn and place a skinmarker over this. Ultrasound was

Page 3: Imaging of plant-thorn synovitis

Immediately after this the childwas taken to the operating room foran exploration and washout of thejoint. The joint was exposed using alateral approach centred over theskin marker. Gross inflammatorychange was found around the elbowjoint, and the capsule was incised re-leasing a large amount of frank pus.The large thorn fragment was locat-ed, found to be encapsulated in a hy-pertrophic mass of synovium, and re-moved (Fig. 3). A partial synovecto-my was performed, with excision of the chronic inflammatory tissue.Microbiological culture of the pusshowed inflammatory pus cells butdid not grow any organisms. Histo-logical examination of the excisedtissue showed that the synovium wascovered by an abundant inflammato-ry exudate. The child has remainedasymptomatic and well since the sur-gery, and at 4-monthly review hadregained a full range of movement inhis elbow.

Discussion

Plant-thorn synovitis occurs when athorn punctures a joint and sets off aforeign body reaction. Symptoms areoften biphasic, initially producing atransient synovitis. Treatment withnon-steroidal anti-inflammatorydrugs, intra-articular steroids and/orantibiotics may settle symptoms tem-porarily, but relapse is common oncetreatment is discontinued. A chronicarthritis may ensue after a relativelyquiescent period, often long after thethorn injury has been forgotten. Inmany cases the patient presumesthey have removed the thorn in itsentirety. However, small or micro-scopic fragments may remain withinthe synovia, triggering a chronic in-flammatory response which will onlysubside when the thorn is completelyremoved at surgery. Unfortunatelyplant thorns are not radio-opaqueand are therefore not detected radio-graphically. The aetiology may re-main undetermined until the offend-ing thorn is found during synovecto-

my, or histological examinationdemonstrates the characteristic gran-ulomatous inflammation with for-eign body giant cells [1, 2, 5, 6, 7].Microscopic examination of the sy-novial fluid may aid the diagnosis,with birefringent vegetable matterseen within the centrifuged sample[1].

In the United Kingdom plant-thorn injuries usually result fromrose thorns (Rosa spp.), and black-thorn (Prunus spinosa), a perennialshrub prevalent in England [1, 3, 4,8, 9, 10, 11]. However a wide spec-trum of vegetation has also been im-plicated in plant-thorn synovitis in-cluding cacti, palms, mesquite,bougainvillea, hawthorns, yucca,black locust plant, box and plum [2, 5, 6, 7]. In our patient, injury wasthought by the mother to have result-ed from a cactus spine, although thiscannot be substantiated.

Thorn injuries can lead to chronicsynovitis, chronic bursitis or chronictenosynovitis, depending on the siteof thorn puncture. Secondary infec-tion may ensue with unusual organ-isms, such as Enterobacter agglom-erans, a Gram-negative bacillus and saprophyte found in soil, water,plants and fruit [8]. Occasionallybony changes can lead to para-articular erosions, or a “pseudo-tumour appearance”, with lytic bonechanges and periosteal reaction mim-icking a sarcoma [6, 7, 10]. Therehas also been one case report wherehypersensitivity to a rose thorn inju-ry is thought to have led to rheuma-toid arthritis [11].

In our institution MRI is com-monly requested to exclude septicarthritis with secondary osteomyeli-tis. This imaging modality does notinvolve radiation, and has the advan-tages of multiplanar imaging and excellent delineation of soft tissues.In the paediatric population, imagesmay be prone to movement artefact,which can be limited by padding the limb within an extremity coil,and the reassuring presence of a parent. MRI has been used previ-ously to demonstrate the presence of

607

non-radio-opaque thorns within softtissues [12, 13], although to ourknowledge there have been no casesof surgically-proven plant-thorn sy-novitis where the thorn fragment hasbeen clearly seen on MRI.

Ultrasound is less expensive andmore widely available than MRI.This technique has been used exten-sively for the detection of foreignbodies both within synovial jointsand in overlying subcutaneous tis-sues [14, 15, 16, 17]. However, ultra-sound is operator-dependent, and itcan sometimes be difficult to differ-entiate small foreign bodies fromnormal anatomical structures. Ultra-sound can be used to both confirmthe presence of a foreign body andplace an overlying skin marker priorto surgical removal. Ultrasound hasalso been used intra-operatively tofacilitate the removal of foreign bod-ies [17].

There has been one case reporton plant-thorn synovitis where athorn has been demonstrated withinthe knee joint on computed tomog-raphy [18]. However, this techniqueis not as sensitive as MRI and ultra-sound, and exposes the patient toradiation.

References

1. Blake DR, et al. Monoarthritis fromblackthorn injury: a novel means of diagnosis. BMJ 1981; 282:361.

2. Carandell M, Roig D, Benasco C. Plantthorn synovitis. J Rheumatol 1980;7:567–579.

3. Kelly JJ. Blackthorn inflammation. J Bone Joint Surg Br 1966;48:474–477.

4. Ormerod AD, White MI, Eastmond CJ,Chesney RB. Plant-thorn synovitis oc-curring in a child with psoriatic arthri-tis. Br J Rheumatol 1984; 23:296–297.

5. Sugarman M, Stobie DG, QuismorioFP, Terry R, Hanson V. Plant thorn sy-novitis. Arthritis Rheum 1977;20:1125–1128.

6. Gerle RD. Thorn-induced pseudo-tumours of bone. Br J Radiol 1971;44:642–645.

7. Yousefzadeh DK, Jackson JH. Organicforeign body reaction. Skeletal Radiol1978; 3:167.

8. Barton LL, Saied KR. Thorn-inducedarthritis. J Paediatr 1978; 93:322–323.

Page 4: Imaging of plant-thorn synovitis

9. Maylahn DJ. Thorn-induced “tumors”of bone. J Bone Joint Surg Am 1951;34:386–388.

10. Southgate GW, Murray RO. Case report 190. Thorn-induced synovitis.Skeletal Radiol 1982; 8: 79–80.

11. Hawkins SJ, Blake DR, Doherty M,Hall ND. Rheumatoid arthritis devel-oping after plant thorn synovitis. BMJ 1982; 285:1620.

12. Maillot F, Goupille P, Valat JP. Plantthorn synovitis diagnosed by magneticresonance imaging. Scand J Rheumatol1994; 23:154–155.

13. Kornreich L, Katz K, Horev G, Keharia A, Mukamel M. Preoperativelocalization of a foreign body by mag-netic resonance imaging. Eur J Radiol1998; 26:309–311.

14. Bianchi S, Martinoli C. Detection ofloose bodies in joints. Radiol ClinNorth Am 1999; 37:679–690.

15. Gooding GAW, Hardiman T, SumersM, Stess R, Graf P, Grunfeld C. Sonog-raphy of the hand and foot in foreignbody detection. J Ultrasound Med1987; 6:441–447.

608

16. Jacobson JA, Powell A, Craig JG,Bouffard JA, van Holsbeeck MT.Wooden foreign bodies in soft tissue:detection at US. Radiology 1998;206:45–48.

17. Sheils WE, Babcock DS, Wilson JL,Burch RA. Localization and guided re-moval of soft-tissue foreign bodieswith sonography. AJR 1990;155:1277–1281.

18. Klein B, McGahan P. Thorn synovitis:CT diagnosis. J Comput Assist Tomogr1985; 9:1135–1136.