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Avascular necrosis (AVN) involves destruction of the hip joint. Long-term use of steroids has been shown to cause AVN. This article presents a case of intra-articular injection of steroid causing a rapid onset of AVN in the hip joint. Bone histology at time of total hip replacement showed evidence of AVN and no evidence of infection.
Avascular necrosis (AVN) of the hip involves rapid destruction of the joint. Radiographic appearances include disappearance of the joint space and destruction of the femoral head. Many causes have been proposed, including infection, inflammatory disease, fracture and osteoarthritis. Physiology of AVN is thought to be due to loss of microvasculature to the femoral head and hip joint.1 Cases have been described of AVN occurring after long-term usage of steroids for conditions such as psoriasis, systemic lupus erythematous, nephritic syndrome and renal transplantation.2–4 No cases have yet been described of onset of AVN after a single intra-articular injection of steroid.
We describe a case of rapid-onset AVN occurring 5 weeks after single injection of corticosteroid into the hip joint.
A 79-year-old man, with no medical comorbidities, presented to an Orthopaedic clinic with ongoing left-knee pain of 9-month duration. On questioning he also described coexisting left-hip pain. He was otherwise fit and well with no other comorbidities and a minimal alcohol intake. Examination of the knee was inconclusive with no obvious abnormalities. However, examination of the hip revealed pain and reduced mobility. Radiographs obtained showed a normal knee but with the beginning of osteoarthritic changes in the left hip (figures 1 and and2).2). It was felt that his knee pain would be accounted for by these changes in his hip and the decision was made to proceed to an intra-articular injection of steroid into the hip to confirm this diagnosis. Preoperatively he was assessed showing a body mass index of 21 and normal inflammatory markers (white cell count and C-reactive protein).
Under theatre aseptic conditions an arthrogram was performed of his left hip, and an intra-articular injection of 8 ml of Chirocaine and 2 ml of Adcortyl (triamcinolone acetonide) was administered (figure 3). This gave symptomatic relief of symptoms for 2 weeks.
Five weeks postoperatively, he presented to the Accident and Emergency department with increasing pain in his left hip. Blood tests showed a normal white cell count but a slightly elevated C-reactive protein on 43 (normal range 0–10). Radiographs performed showed destruction of joint space in the left-hip joint and destruction of the left femoral head (figures 4 and and55).
No evidence was found of renal or hepatic dysfunction and there was no evidence of diabetes. The patient denied usage of illicit medications or of any trauma to his left leg.
MRI performed showed AVN of the left hip with bone oedema and no obvious infective change (figure 6). These would be consistent with a maximal Ficat score of 4 for the classification of AVN. This is determined on his x-ray and MRI findings of end-stage AVN. His pre-steroid injection score would be 0 with no signs of AVN and no obvious hip pain.5
A left-sided total hip replacement was subsequently performed. Femoral head histology showed extensive necrosis with a prominent histiocytic and fibroblastic reaction including osteoclasts. There was no evidence of infection and the features were of AVN.
The patient recovered well postoperatively, and his pain was resolved after physiotherapy. He was able to return to his preadmission level of mobility.
Long-term topical and systemic steroids have been speculated as a possible cause of AVN in joint surfaces. However, cases presented have tended to be after long-term administration. No cases appear to have been described with rapid destruction poststeroid administration. It appears very likely that, in this case, the intra-articular injection of steroids was the cause of the rapid deterioration of the femoral head and subsequent AVN.
Steroids are known to reduce the bloods flow to the femoral neck, and it can be extrapolated that this could have caused the rapid destruction in this case.
In view of this case, it would be advisable that this side-effect of steroid administration should be explained to the patient prior to obtaining any form of consent.
Competing interests None.
Patient consent Obtained.