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Case 230


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VBRS, female pacient, 52 years old, underwent a total left knee arthroplasty 3 years ago. In the early postoperative, presented dehiscence of the surgical wound dress-ings and was treated with oral antibiotics. The patient developed pain refractory to the use of oxycodone. The clinical examination identified pain through mobilization of the left knee joint, local heat and movement of 5-110 ° and limping gait aided by walker. Protein C reactive dosage equal to 20 mg / dL (VR <10mg / dL), VHS and blood test within the reference values.

Based on the clinical and imaging data, which is the most likely diagnosis?

a) Patellofemoral pain


b) Septic loosening of the knee prosthesis


c) Joint instability after arthroplasty


d) Inappropriate dimensioning of components


Image analysis

Image 5: Radiograph of the left knee in the incidences anteroposterior and profile. Osteolysis line is observed on the periphery of the femoral and tibial components ( highlighted in yellow) and proper alignment and dimensioning of the prosthesis.

Image 6: Three-phase bone scintigraphy with 99mTc -MDP showing abnormal high uptake periprosthetic of the left knee in moderate degree ( highlighted in orange).


Image 2: Three-phase bone scintigraphy with 99mTc -MDP- flow phase.


Image 3: Three-phase bone scintigraphy with 99mTc -MDP- blood pool phase showing symmetrical blood flow and increased blood pool in the projection of the left knee joint.


- Total knee arthroplasty (TKA) is the procedure of choice for treatment of pain related to refractory osteoarthritis to conservative treatment;

- TKA can not eliminate the pain in 20% of patients;

- The septic loosening (SS) of the bone prosthesis is the main cause of revision of TKA;

- The evaluation of post TKA pain includes clinical examination, laboratory investigation, imaging and microbiological studies;

- Radiography is a method of low specificity for the diagnosis of the SS of the bone prosthesis;

- The prosthetic joint loosening is radiographically translated by: continuous radiolucent line with thickness exceeding 2mm or peri-prosthetic focal osteolysis;

- The Three-phase bone scintigraphy with 99mTc-MDP is a sensitive test (75%) but  has low specificity (55%) for the diagnosis of SS knee prosthesis. Therefore it may be resorted to comparative analysis with scintigraphy 67Galium citrate;

- Diffuse uptake changes in bone scintigraphy are considered normal up to 2 years after surgery.


- The Painful Total Knee Arthroplasty. Orthop Clin North Am, v. 47, n. 2, p. 317-26. doi: 10.1016/j.ocl.2015.09.008., Apr 2016. ISSN 1558-1373 (Electronic) 0030-5898 (Linking). 

- Prosthesis infection: diagnosis after total joint arthroplasty with three-phase bone scintigraphy. Ann Nucl Med, v. 28, n. 10, p. 994-1003. doi: 10.1007/s12149-014-0899-5. Epub 2014 Aug 29., Dec 2014. ISSN 1864-6433 (Electronic) 0914-7187 (Linking). 

- Prosthetic joint infections: radionuclide state-of-the-art imaging. Eur J Nucl Med Mol Imaging, v. 39, n. 5, p. 892-909. doi: 10.1007/s00259-012-2062-7. Epub 2012 Feb 24., May 2012. ISSN 1619-7089 (Electronic) 1619-7070 (Linking).  


Talita de Araújo Pereira, 6th year medical student at UFMG

E-mail: talitaap[at]


Rafael Waldolato Silva, 6th year medical student at UFMG



Marcelo Peixoto Sena Silveira, 3rd year resident doctor in Orthopedics and Traumatology at Hospital das Clínicas - UFMG

E-mail: marcelopssbr[at]


Túlio Vinícius de Oliveira Campos, Assistant Professor of the Locomotor Department at UFMG – Master in Molecular Medicine at UFMG – Coordinator of Orthopedic and Traumatology Service at  Hospital Universitário Risoleta Tolentino Neves.

E-mail: tuliovoc[at]


André Guimarães, Fernando Bottega, Gustavo Campos, Fellype Borges, Cairo Mendes, Lucas Müller.

Translated by 

Laio Bastos de Paiva Raspante, 4th year medical student at Universidade Federal de Minas Gerais.

E-mail: laioopaiva[at]

Test question












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