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Case 258


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Male patient, 56 years old, presented a severe acute exacerbation of chronic low back pain (present for 3 months), with irradiation to left inguinal region. He denies previous trauma, but underwent total knee arthroplasty (TKA) for treatment of osteoarthritis thirty days ago. On examination: Poor oral hygiene. Painful palpation of left paravertebral lumbar region. No neurological deficits. Right knee with moderate joint heat and effusion, with no fistula. Laboratory tests: CRP: 232 mg/L, ESR: 115 mm/h and leukocytosis with left shift. Imaging studies of lumbar spine were performed (Figures 1, 2 and 3).

Based on clinical data and imaging tests, what is the most likely sequence of events in this case?

a) Periodontal disease → Knee prosthesis infection → Spondylodiscitis


b) Periodontal disease → Spondylodiscitis →Knee prosthesis infection


c) Knee prosthesis infection → Spondylodiscitis → Greater left psoas muscle abscess


d) Knee prosthesis infection →Greater left psoas muscle abscess → Spondylodiscitis


Image Analysis


Figure 1: Lumbar spine radiograph, profile incidence. Reduction of L3-L4 disc space, small gas accumulation in L3-L4 disc space, associated with adjacent partial subchondral sclerosis.


Figure 2: Tomography of lumbar spine, without intravenous contrast. A. Axial cut, level L3-L4. Small gas accumulation in the disc space (green). Enlarged left psoas muscle, with a hypoattenuating area at its medial border, with poorly defined limits, compatible with abscess (red). B. Sagittal reconstruction. Reduction of L3-L4 intervertebral space, associated with small gas accumulation, somatomarginal osteophytes (purple), irregularities in vertebral surfaces and adjacent subchondral sclerosis (yellow). Anterolistesis of L3 on L4, grade I (blue).


Figure 3: Magnetic resonance, sagittal cut, in T2 - reduction of L3-L4 disc space, associated with posterior disc bulging, which causes compression of adjacent structures.


Infection after total knee arthroplasty is not a rare complication (see case 230). However, there are few literature reports on timing between knee prosthesis infection and spondylodiscitis. In this patient, it is more probable that the spine infection was an earlier event and, when performing the arthroplasty without diagnosis of the ongoing infection (the chronic low back pain was considered noninfectious), the hematogenous spread to the knee occurred. This suspicion is based on the advanced degree of evolution of spondylodiscitis at the time of diagnosis, since its natural history is usually insidious. Furthermore, findings in the patient's imaging studies suggest a chronic affection. The presence of destruction, fractures and collapse of vertebral bodies, with medullary compression, for example, is commonly seen only after 4 to 8 weeks of infection. In addition, the extent of infection to adjacent soft tissues, such as the left psoas muscle in this case, is usually a complication of a sustained spinal involvement. As the knee intervention was performed only 30 days ago, the knee prosthesis infection must have been the last event in the succession of events.

The association between poor oral hygiene and transient bacteremia, including staphylococcal, is described in literature. Therefore, periodontal disease is the most likely triggering event in the whole process.


- Spondylodiscitis is an inflammatory and infectious process that usually strikes contiguous vertebral bodies and adjacent intervertebral disc;

- Staphylococcus aureus is the most common etiologic agent and hematogenic route is the most frequent route of dissemination;

- Symptoms of pyogenic spondylodiscitis are nonspecific, with spinal tenderness often associated with restricted range of movement and paravertebral muscle spasm being the commonest sign detected on examination;

- The aim of treatment is to eradicate the infection, relieve pain, and restore or preserve the structure and function of the spine;

- There is an association between poor oral hygiene and transient bacteremia, including staphylococcal.

- It is recommended to refer every patient planning joint replacement surgery to the dentist.


  • - Garcia, E.C., Braga, C.A., Ferreira, C.A.L., Mendes, G.S. (2013). Espondilodiscite: um diagnóstico diferencial raro de dor abdominal. Rev Med Minas Gerais; 23.3:392-395, Jul/Set, 2013

  • - Friedlander, A. (2010). Oral Cavity Staphylococci Are a Potential Source of Prosthetic Joint Infection. Clinical Infectious Diseases, 50(12), pp.1682-1683.

  • - Smith, A., Robertson, D., Tang, M., Jackson, M., MacKenzie, D. and Bagg, J. (2003). Staphylococcus aureus in the oral cavity: a three-year retrospective analysis of clinical laboratory data. British Dental Journal, 195(12), pp.701-703.

  • - Murdoch, F., Sammons, R. and Chapple, I. (2004). Isolation and characterization of subgingival staphylococci from periodontitis patients and controls. Oral Diseases, 10(3), pp.155-162.

  • - McCormack, M., Smith, A., Akram, A., Jackson, M., Robertson, D. and Edwards, G. (2015). Staphylococcus aureus and the oral cavity: An overlooked source of carriage and infection?. American Journal of Infection Control, 43(1), pp.35-37.

  • - Sobottke, R., Seifert, H., Fätkenheuer, G., Schmidt, M., Goßmann, A., & Eysel, P. (2008). Current Diagnosis and Treatment of Spondylodiscitis. Deutsches Ärzteblatt International, 105(10), 181–187.


Lucas Augusto Carvalho Raso, academic of the 5th year of the Faculty of Medicine of UFMG.

E-mail: lucasraso[at]


Túlio Vinícius de Oliveira Campos, Assistant Professor, Department of Locomotor Apparatus, Faculty of Medicine UFMG, Master in Molecular Medicine and Coordinator of Orthopedics and Traumatology Service, University Hospital Risoleta Tolentino Neves, Belo Horizonte, MG.

E-mail: tuliovoc[at]


Rafael Fusaro, Fernando Bottega, Mateus Oliveira, Prof. Jose Nelson M. Vieira, Profa. Viviane Parisotto.

Translate by

Juliana Albano de Guimarães, academic of the 6th year of the Faculty of Medicine of UFMG.

E-mail: julianaalbanog[at]


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