Orthopedics: DDH, Gout, Osteomyelitis, Septic Arthritis

General Orthopedics

• Developmental dysplasia of the hip (DDH) includes dysplasia, subluxation and possible dislocation, occurring in 1 in 1000 births, bilaterally in 20% of cases.
• Risk factors for DDH include being firstborn, female (6:1 ratio), breech presentation, oligohydramnios, footling breech position, family history, and macrosomia.
• In DDH, a pseudoacetabulum may form as a teratological change, in addition to anterior or anterolateral acetabulum deficiency.
• "Packaging" deformities associated with DDH include congenital muscular torticollis, metatarsus adductus, congenital knee dislocation, and clubfoot.
• Swaddling poses a risk, while spread squat baby wearing is beneficial for babies.
• Anatomical changes in DDH involve thickening of the pulvinar, an inverted capsule and limbus, thickening and elongation of the ligamentum teres, hypertrophy of the transverse acetabular ligament, and an hourglass configuration of the hip capsule and iliopsoas.
• Diagnostic tests for DDH include Barlows, Ortolani, Galeazzi tests (at 3 months), assessment of skin fold asymmetry, Trendelenburg sign, limited abduction, LLD, and Klisic test.
• Ultrasound is the preferred imaging method in the first 4 months, and AP pelvis radiographs performed later.
• Universal screening for DDH focuses on risk factors.
• On X-ray, an acetabular roof angle <30° is considered normal.
• Hilgenreiner's line is observed, and the normal femoral head is medial to Perkin's line and inferior to Hilgenreiner's line.
• An arthrogram showing a dye pool >7mm necessitates a CT scan to confirm reduction.
• Treatment options include the Pavlik harness (dynamic abduction brace) for infants <6 months, CR + hip spica for 6-18 months, and OR + FO >2 years.
• Pelvic osteotomy (Salter, Pemberton, Dega) is considered for children >4 years.

Perthes Disease

• Perthes is characterized by idiopathic avascular necrosis of the proximal femoral epiphysis in children.
• It is more common in males aged 4 to 8 years, with a positive family history, ADHD association, and bilateral involvement in 12% of cases.
• Diagnosis involves Waldenstrom classification, lateral pillar classification, and assessment of the Stulberg prognosis.
• Features include the Gage sign (v-shaped radiolucency), calcification, subluxation, a metaphyseal cyst, and horizontal physis.
• Patients present with a painless limp, more pronounced in the evening, accompanied by hip/knee pain radiating along the leg.
• MRI is more effective than X-rays in detecting Perthes, and arthrograms may also used.
• Containment strategies involve femoral and pelvic osteotomy.

Slipped Capital Femoral Epiphysis (SCFE)

• SCFE involves slippage of the metaphysis relative to the epiphysis at the hypertrophic zone, most commonly seen in adolescent obese males, with bilateral involvement in 50% of cases.
• Associated conditions include endocrinopathies (hypothyroidism, renal osteodystrophy, growth hormone deficiency) and Down syndrome.
• Loder classification is based on pain.
• Diagnosis includes X-ray assessment of the Southwick slip angle and Klein's line.
• An MRI is used in cases of preslip.
• Patients complain of hip/knee pain with obligatory external rotation.
• Treatment involves in situ fixation with screws.

Tibial Bowing

• Tibial bowing can be anterolateral (associated with congenital pseudarthrosis), anteromedial (consider fibular hemimelia), or posteromedial (benign with spontaneous improvement).

Clubfoot (Congenital Talpies Equinovarus)

• Clubfoot is a common congenital deformity (1:1000), typically idiopathic.
• Associated conditions include arthrogryposis and Larsen syndrome.
• Diagnosis typically requires X-rays (Turco view, kite angle) and Pirani/Dimeglio scoring.
• Ponseti casting or French methods are common treatments.
• Complications include relapse or dynamic supination.
• Percutaneous TA tenotomy may also be performed (85%)
• Correction is maintained with a DB splint (foot abduction orthosis) / CTEV shoe.
• Talectomy / Triple arthrodesis (TN, CC, TC) or Ilizarov methods can be used in older patients.

Congenital Vertical Talus

• Congenital vertical talus is associated with neuromuscular or chromosomal abnormalities.
• The navicular bone is dorsally dislocated related to the vertical talus.
• Diagnostic findings include Meary angle >20, rigid flatfoot, and rocker bottom foot.
• Treatment involves reverse Ponseti.
• Planus foot, tarsal coalition, CVT, flexible flatfoot, and accessory navicular should be differentiated.

Osteogenesis Imperfecta

• Osteogenesis imperfecta involves type 1 collagen.
• Patients experience brittle bones with fragility fractures, scoliosis, hearing loss, and cardiovascular abnormalities.
• Inheritance is autosomal dominant and autosomal recessive.
• Fractures initially heal normally, but the bone does not remodel well.
• Clinical signs include blue sclera, dentinogenesis imperfecta.
• The Sillence classification is used.
• Bisphosphonates are used for treatment.

Osteopetrosis

• Osteopetrosis, or marble bone disease, is due to osteoclast dysfunction, leading to increased predisposition to fracture.
• Radiographic signs include a bone-in-bone appearance and "rugger jersey spine.
• Lab findings show increased acid phosphatase.
• Results in delayed union and weaker bones.
• Treatment includes bone marrow transplant and calcitriol.

Achondroplasia

• Achondroplasia, is a skeletal dysplasia caused by the FGFR3 gene.
• Patients exhibit disproportionate dwarfism, rhizomelic dwarfism, and a large head.
• Intelligence is normal.
• Physical characteristics include trident hands, spinal stenosis, decreased interpedicular distance and short pedicles
• Radiological presentation showcases a champagne glass pelvis with squared iliac wings.

Bone Disorders: Lab Values

• In osteoporosis, calcium, phosphate, ALP, and PTH levels are normal.
• Osteomalacia shows decreased calcium and phosphate, with increased ALP and PTH.
• Primary hyperparathyroidism elevates calcium, ALP & PTH.
• Chronis Kidney Disease decreases calcium, while increasing phosphate, ALP & PTH.
• Paget's disease elevates the ALP level
• Osteopetrosis show normal calcium, phosphate, ALP and PTH.

Osteoporosis

• Osteoporosis involves a decrease in bone mass and disruption of bone microarchitecture, quantitative disorder of bone mineralization.
• Diagnosis via lumbar-based DEXA scan.
• Risk Factors include hypogonadism, glucocorticoid excess and alcoholism.
• Increases Risk of fragility fracture in vertebral bodies, peritrochanter femur and distal radius.
• Two main types: Type I (postmenopausal) and Type II (senile).
• Management: calcium, vitamin D, bisphosphonates, conjugated estrogen-progestin hormone replacement (HRT), salmon calcitonin, SERM raloxifene, teriparatide, denosumab, and romosozumab.

Osteomalacia vs Osteoporosis

Rickets

• Rickets is the matrix's (osteoid) failure to mineralize.
• Caused by inadequate calcium and phosphate intake.
• Occurs at the provisional zone of calcification.
• Increased physeal width and bow-leggedness (cortical thinning).
• Bone is brittle with deformity + ligamentous laxity.
• Widening of osteoid seams, "swiss cheese" trabeculae.

Gout vs Pseudogout

• Gout can cause podagra, due to monosodium crystals in the joints which causes a breakdown of purines.
• Treatment for gouty arthritis is indomethacin vs. colchicine vs glucocorticoid, or Febuxostat/Allopurinol (oxide inhibitor).

Osteomyelitis

• Osteomyelitis is hematogenous seeding of bacteria in the metaphyseal region of bone.
• Staph Aureus is MC, pseudomonas in the foot via puncture wound. While, Salmonella, is seen in patients with sickle-cell.
• Vessels arrange in "hairpin" loops at metaphysis.

Chronic Osteomyelitis

• Characterized by:
  • Sequestrum (necrotic bone)
  • Involucrum(new bone growth + sclerosis).
  • Cloacae(multiple openings).
• Diagnosis will always require tissue.
• Brodie's abscess occurs if surrounded by fibrous tissue, or sclerotic bone.
• Often seen in immunocompetent hosts that are less virile.
• Can be acute or subacute OM.
• High-grade fever, swelling, bony tenderness and restricted ROM.
• X-ray findings:
  • Soft Tissue changes that are soft: 2-weeks after, metphyseal rarefaction, and periosteal reactions.
  • BONE.
  • Best detection is via MRI. Bone scan(Tc99) can detect/localize early infection.
• CRP, ESR rises
• Pathological fracture
• Tx includes drainage/decompression

Septic Arthritis

• Staph Aureus is MC in Intra-articular metaphysis.
• Look in joints like: hip, shoulder, elbow, ankle (NOT the knee).
• Pseudoparalysis.
• Flexion, abduction, and external rotation posture.
• Tom Smith arthritis: infancy in hip, head destruction.
• Treated with antibiotics.

Kocher's Criteria to Differentiate Septic Hip Arthritis vs Transient Synovitis

• Probabilities of septic arthritis increase with each criterion met:
  • 0 criteria: 2%
  • 1 criteria: 9.5%
  • 2 criteria: 35%
  • 3 criteria: 73%
  • 4 criteria: 93%

Spinal Tuberculosis

• Aka Pott's disease, MC in thoracic spine.
• IVD damaged, decreased disc pressure/height
• Look for edema/myelomalacia and syringomyelia
• Pseudoflexion of hip secondary to psoas abscess.
• Decompression.
• Middle path treatment.

Osteoarthritis

• Presents joints space narrowing, subchondral sclerosis and subchondral cysts.

Rheumatoid Arthritis

• RA is a systemic autoimmune disease.
• Cell-mediated IgM attack.
• Joint destruction from Synovial pannus, joint subluxation and deformity, and tendon instability.
• Look for Felty's (splenomegaly + leukopenia), Stills(RA + fever + rash + splenomegaly), and Sjogren's (attacks exocrine glands).
• Ulnar drift, and MCP commonly involved.

- Ankylosing Spondylitis

• Typically involves sacroiliac joints, causing pain and stiffness.
• Can lead to fusion of the spine.
• Symptoms often improve with exercise and worsen with rest.

- Reactive Arthritis

• Commonly follows a bacterial infection, such as Chlamydia or Salmonella.
• Primarily affects lower extremities.
• May cause skin and eye inflammation.

Juvenile Idiopathic Arthritis

• Juvenile Idiopathic Arthrits is chronic auto-inflammation.
• Must be 6 weeks in <16 years of patients.
• RF - seropositive <15%, knee usually targeted.
• Still's disease, acute fever and splenomegaly+rash.
• Pauciarticular w/ best prognosis.

Ankylosing Spondylitis

• HLA-B27 test is positive for spondylitis. In addition, Romanus lesions, Andersson lesions and syndesmophytic ankylosis "bamboo spine"
• Ankylosing Spondylitis is categorized under Spondyloarthropathies,.
• anterior uveitis can be seen alongside.

Reactive Arthritis

• Reactive Arthritis involves urethritis, arthritis and conjunctivitis.
• Can't see, can't climb, can't pee.
• Immune response with enteric bacterias: Salmonella, Shigella, Yersinia, Chlamydia.

Osteochondritis Dissecans

• MC OCDs occurs in the medial femoral condyle.

Enneking Staging System

• Categorized for benign Tumors/Cysts staging: Active, Latent, and Aggressive.
• Staged based on metastasis, grade and site.

Tumors

- Diaphysis

• Fibrous Dysplasia
  • Epiphysis
• GCT
  • Metaphysis
• Osteochondroma
• Round cell tumors, Langerhans cell
• Adamantinoma/osteomyelitis is found in diaphysis
• Giant Cell Tumor GCT is found in epiphysis

Osteoid Osteoma

• Ages 5 and 25. Pain that is worse at night. Relief with NSAIDS
• Can progress to osteoblastoma. Osteoid Osteoma = <1.5cm nidus
• "double-density sign"

Osteosarcoma

• Lung, femur, or tibia are common locations in young patients
• Commonly due to Li-Fraumeni Syndrome, Rb
• Commonly metastatic, treat with resect of osteoid.
• Sun-burst or hair on end pattern matrix.

Enchordoma

• Ages 20 TO 50
• Typically in the HANDS

Osteochondroma

• Common in <30year old
• Benign, cartilage cap, must be resected if symptomatic

Chondroblastoma

• A "chickenwire" pattern.
• Ages 10-20.

Chondrosarcoma

• Age 40.
• "Blue balls", wide surgical decision

Osteomyelitis

• Multipel myeloma results in "punched out" lytic lesions. It's characterized with the bence jones/proteins.

Chordomas

• A malignant tumour in patients above 50 years of age which results in bowel or balder dysfunction
• The tumor contains foamy vacoulated physalifirous.

Bone Cysts

• Unicameral tumors result in "fallen leaf". Can be treated with bone graft and curettage.

Aneurysmal Bone Cysts

• Femur and tibia are common locations in patients <20yrs
• Consist of "bubbly" appearances and curettage

Paget's Disease

• Paget's diasease happens idiopathicly that can cause pelvic or skull deformation (cotton wool) >40 year olds, treat with bisphosponates as the serum ALP is elevated

Gigant Cell Tumor

• Benign tummor that happens at 30 -50 that happens in epiphysis and boarders the subchondral bone

Ewing Sarcoma

• Ewings sarcoma is composed of sheets small blue cells

Metastasis

• MC involves the breast, lung, thryroid, kidney and prostate

Spincal Cord Injuries

Spine

• Disc herniation MC: L4/L5
• Most common is posteriolateral disch

Cauda Equina

• Saddle anesthesia + bowel dysfunction

Aidoslecent Scoliosis

• MC Females and Right Thoratic Curbe are more prominant

Radial Nerve PalsyTest

• is done by hitchicker sing

Medial Nerve PalsySign

• Is done by app hand and Ocnser test

Questions cover developmental dysplasia of the hip (DDH), gout, osteomyelitis, and septic arthritis. Topics include risk factors, diagnosis, and common organisms related to these conditions. Also includes rheumatoid factor.