Infections of the Bone MCQs

Answer- B. Joint aspiration Quickest and best method of diagnosis of septic arthritis is aspiration of joint.

Septic arthritis is an absolute orthopedic emergency as delaying arthrotomy can cause serious joint damage. The pus in septic arthritis contains collagenases and metalloproteinases that start destroying articular cartilage within a period of 8 hours. So arthrotomy and lavage should be done as early as possible. Reference: Tachdjian's Pediatric Orthopaedics 5th edition page no. 1055

GARRE'S OSTEOMYELITIS Sclerosing non suppurative chronic osteomyelitis Fusiform osseous enlargement. Cortical thickening No discharging sinus There is tenderness on deep palpation Shafts of the femur or tibia are most common site Treatment is guarded. Acute symptoms subside with rest and broad-spectrum antibiotics. Sometimes, making a gutter or holes in the bone bring relief in pain. Reference: Maheshwari Essential Orthopedics, 7 th edition, Page no. 173.

Most common site is mandible GARRE'S OSTEOMYELITIS: Sclerosing non suppurative chronic osteomyelitis Fusiform osseous enlargement. Cortical thickening present. No discharging sinus There is tenderness on deep palpation Overall mandible is most common site. Shafts of the femur or tibia are other most common site Treatment is guarded. Acute symptoms subside with rest and broad-spectrum antibiotics. Sometimes, making a gutter or holes in the bone bring relief in pain. Reference: Maheshwari Essential Orthopedics, 7 th edition, Page no. 173.

Note that responsible pathogens may be isolated in only 35-40% of infections. Bacterial causes of acute hematogenous and direct osteomyelitis include the following: Most common organism causing acute osteomyelitis: Staph. Aureus MCC of osteomyelitis in sickle cell anemia patient: SALMONELLA MCC of osteomyelitis in IV drug abuser: PSEUDOMONAS MC organism causing osteomyelitis in open foot injury: PSEUDOMONAS MC organism causing osteomyelitis in HIV patient: Staph. Aureus MC organism causing osteomyelitis in case of animal bite: Pasteurella Multiocida MC organism causing osteomyelitis in case of human bite: Eikenella Corrodens Reference: Maheshwari Essential Orthopedics, 5th ed, Pg: 168.

Remodeling is the process by which bone gets reshaped according to external forces. This a slow, continuous and dynamic process. Here, some bone is removed form certain areas and some bone gets deposited in other areas, so both osteoblasts and osteoclasts are needed for remodeling. Reference: J. Maheshwari's 5th Edition of Essential Orthopaedics page no. 11 Reference: Campbell's Operative Orthopaedics 14th edition page no. 1186

Osteoblast is the bone building cell. It produces all the proteins needed to make up bone tissue, which includes type I collagen, osteocalcin, osteonectin etc It also produces an important enzyme, Alkaline phosphatase, which can be used as a marker for bone formation. Reference: Miler's 8th Edition of Review of Orthopaedics, page no. 18.

When a child comes with a lytic lesion in the proximal humerus there are 3 possibilities Simple bone cyst - It will appear as a cyst in the metaphysis. Chondroblastoma - It will appear as a lytic lesion in the epiphysis. Metastasis - Even though rare, mets can occur in the proximal humerus in a child e.g. neuroblastoma Plasmacytoma is a solitary myeloma and is always seen in elderly patients and never in this age group Reference: J. Maheshwari's 5th Edition of Essential Orthopaedics page no. 245