[A muscular calcium pyrophosphate deposition pseudo-abscess: An atypical localization of chondrocalcinosis]. / Pseudo-abcès musculaire d'origine microcristalline : une localisation exceptionnelle de chondrocalcinose.

INTRODUCTION: Chondrocalcinosis results from calcium pyrophosphate crystals deposition in the joints. We report an exceptional case of aseptic psoas abscess with a deposition of calcium pyrophosphate crystals. CASE REPORT: A 92-year-old man presented to our department for an acute onset of inflammatory pain in the left hip. Computed tomography detected a coxofemoral arthritis and multiple intramuscular collections located in the iliopsoas muscle and the gluteus minimus. A sample of the fluid was obtained with a guided aspiration, and its analysis revealed an inflammatory liquid with no bacteria but numerous calcium pyrophosphate crystals. The final diagnosis was thus a muscular calcium pyrophosphate deposition pseudo-abscess, associated with a hip arthritis. CONCLUSION: Hip chondrocalcinosis is unusual, and the association with intramuscular deposition of calcium pyrophosphate crystals seems extremely rare as we found only four other published cases. A microcrystalline arthritis could have spread from the coxofemoral joint through the iliopsoas bursa and into the muscle. However, the imaging aspect with an abscess and a predominant muscular injury might suggest a mechanism of crystal formation originating directly within the muscle. The outcome was always favourable even if some patients required surgery.

Incidental discovery of an undisplaced ceramic liner fracture at total hip arthroplasty revision for squeaking.

Squeaking has been reported after ceramic-on-ceramic total hip arthroplasty (THA), but its pathomechanics is not fully understood. Impaired lubrication is suspected to be the main reason. The management of patients impacted by this phenomenon is not well defined and, as it is not considered to be cause for alarm, revision is not strongly recommended. Here, we describe a ceramic insert fracture discovered during revision surgery performed to correct severe squeaking. Preoperative investigation (plain X-rays, ultrasound and computed tomography) did not reveal ceramic fracture or definite component malposition. To date, there are no other published cases of incidental discovery of a bearing component fracture during revision of ceramic-on-ceramic hip replacement due to squeaking. We believe that squeaking is not a trivial phenomenon and recommend careful management of patients suffering with this symptom.

[Clostridium difficile reactive arthritis in a 7-year-old child]. / Polyarthrite réactionnelle àClostridium difficile chez un enfant de 7ans.

Clostridium difficile reactive arthritis is a rare disease; only 5 pediatric cases have been reported in the literature. Its diagnosis is challenging. It manifests as asymmetric aseptic poly- or oligoarthritis, contemporary to infectious colitis, usually after a period of antibiotic therapy. We report a new case in a 7-year-old boy who presented with unusual polyarthritis affecting 12 joints 1 month after antibiotic therapy with amoxicillin-clavulanate. Punctures of both hip joints proved sterile but significantly improved symptoms. Diarrheic stool cultures during hospitalization provided the diagnosis. Antibiotic therapy using metronidazole completely resolved pain and joint swelling within a week. After 1 year of follow-up, there has been no recurrence. We present a review of the literature on this disease and underline the advantages of joint aspiration in this condition with the dual aim of not missing septic arthritis and effectively relieving pain.