Abstract

1.1.Introduction:Psoas abscess is a collection of pus within the psoas muscle compartment that can access the hip joint in rare opportunities through the psoas bursa. Usual treatment involves articular toillet at early diagnosis, but when not suspected, secondary arthritis or septic arthroplasty loosening may occur. To our knowledge there are no reports of 2 stages radical treatment for this case.

1.2.Material and methods:We describe two cases of primary psoas abscess with partial response to oral antibiotic treatment in whom the infection spread to the hip joint, leading to a septic arthritis. The first case was a 60 year old diabetic male patient with 2 months thigh pain and fever treated with oral antibiotics and torpid evolution. CT scan and MRI showed a left psoas abscess in contact with the hip joint interpreted as an advanced hip arthritis with severe cartilage damage. The second case is a 42 year old male patient who had a psoas muscle tear while playing football 3 weeks before consultation that complicated with psoas infection and bad response to antibiotics. MRI showed a clear collection in iliac fossa and advanced articular damage associated to synovitis. 2 stage treatments consisted in an initial surgery through a posterior approach, debridement of inflammatory tissues, neck osteotomy and acetabular reaming adding a temporary antibiotic impregnated cement spacer for the resected femoral head. 6 weeks after when intravenous antibiotic treatment was completed and laboratory inflammatory parameters were controlled; a second stage surgery was planified: Conversion to an hybrid arthroplasty for the first case and a non cemented total hip arthroplasty for the second case.

1.3.Results:Differed anatomy showed chronic inflammation compatible with osteomielitis for both cases, no germs were isolated in the cultures for the case 1 and a staphylococcus aureus meticilin resistant organism for the second case. At conversion stage cement spacer loaded with antibiotics did not mantain articular length witch made conversion more demanding, suggesting that a preformed spacer can cope with both objectives, controlling infection and maintaining articular length. 2 year follow up with excellent clinical results, infection markers controlled, no complications reported. Harris Hip Score were over 90 in both cases.

1.4.Conclusion:Though it is a rare complication of psoas abscess, septic hip arthritis is an invalidating disease. Radical treatment with 2 stages surgery, accomplished good results for this devastating arthropathy. An Articulated spacer is suggested. 

Keywords

Psoas abscess, Muscle compartment, Hip joint, Usual treatment, Articular toilet, Early diagnosis, Secondary arthritis, Radical treatment, Antibiotic treatment, Chronic inflammation, Hip arthritis, Primary psoas abscess, Torpid evolution, Locomotor examination, Inflammatory parameters.