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Patellar Tendinopathy — Jumper’s Knee
Overuse injury of patellar tendon, common in jumping athletes (basketball, volleyball). Pain localized to inferior pole of patella; worse with jumping, squatting, stairs. Histology: degenerative tendinosis, not acute inflammation. Clinical: localized tenderness, decline squat test positive. Management: eccentric strengthening, activity modification, NSAIDs, PRP; surgery for refractory cases.
Open topicPatellofemoral Complications in TKA
Commonest source of dissatisfaction after TKA. Includes anterior knee pain, maltracking, subluxation/dislocation, fracture, loosening of patellar component. Risk factors: malrotation of femoral/tibial components, improper patellar preparation, soft tissue imbalance. Investigation: clinical exam, skyline view radiographs, CT for malrotation. Management: physiotherapy, lateral release, component revision, patellar resurfacing as indicated.
Open topicPatellofemoral Instability
Common in young females; often after acute lateral dislocation. Risk factors: trochlear dysplasia, patella alta, increased TT-TG distance, ligamentous laxity. Clinical: recurrent dislocation, apprehension sign, medial tenderness. Imaging: MRI shows MPFL injury, chondral damage; CT for TT–TG. Management: conservative after first dislocation; MPFL reconstruction ± tibial tubercle osteotomy for recurrent cases.
Open topicPatellofemoral Pain Syndrome (PFPS)
Common cause of anterior knee pain in young adults, esp. females (‘runner’s knee’). Etiology: maltracking due to Q-angle increase, muscle imbalance, overuse. Clinical: diffuse anterior knee pain, aggravated by stairs, squatting, prolonged sitting (‘movie sign’). Imaging: usually normal; MRI may show chondromalacia patella. Treatment: activity modification, physiotherapy, VMO strengthening, taping; surgery rarely indicated.
Open topicPathological Fractures — Workup
Stage before biopsy: define lesion (X‑ray/MRI) and search for primaries (CT CAP, bone scan/PET). Adult common cause is metastasis (BLT KP) or myeloma; in children, benign lesions (UBC/ABC, fibrous dysplasia). Biopsy tract must align with planned incision; core biopsy preferred; avoid contaminating compartments. Stabilize impending/complete fractures with nails/plates ± cement; endoprosthesis for major destruction. Adjuvant systemic therapy and radiotherapy per histology; bisphosphonates/denosuma...
Open topicPatient-Specific Instrumentation in Arthroplasty
PSI uses preop MRI/CT to fabricate custom cutting jigs. Goal: improve accuracy, reduce OR time/inventory; evidence shows marginal accuracy gains without clear functional benefit. Limitations: cost, imaging/manufacture time, error propagation if imaging off. Best reserved for complex deformity or limited instrument settings. Distinguish PSI (custom guides) from custom implants (rare).
Open topicPauwels Classification — Femoral Neck (Shear Angle)
Type I: 50° (most vertical → highest shear). Higher angle = higher shear → instability, nonunion risk; stronger fixation needed.
Open topicPCL Injuries — Diagnosis & Management
PCL resists posterior tibial translation. Mechanism: dashboard injury, fall on flexed knee with foot plantarflexed. Clinical: posterior sag sign, posterior drawer test, quadriceps active test. Isolated low-grade PCL often treated nonoperatively. High-grade or multi-ligament injuries need reconstruction.
Open topicPCL Injury
PCL prevents posterior tibial translation; stronger than ACL. Mechanism: dashboard injury (posterior force on tibia), hyperflexion. Clinical: posterior sag sign, posterior drawer test. Imaging: MRI confirms tear; X-ray for avulsion fracture. Management: Grade I–II partial tears—conservative; Grade III/chronic—surgical reconstruction.
Open topicPediatric Supracondylar Humerus Fracture
Gartland I–III (± IV for multidirectional instability). Complications to watch: **brachial artery injury**, **median/anterior interosseous nerve palsy**, **compartment syndrome**, **cubitus varus**. Radiographic checks: **Baumann angle**, **anterior humeral line** intersecting capitellum, and **medial comminution** (varus risk). Preferred fixation: **crossed pins** for maximal stability vs **lateral‑entry 2–3 pins** to avoid ulnar nerve injury—technique‑dependent choice. Urgent reduction/pinning...
Open topicPelvic Ring Injuries — ATLS & Tile
ATLS: binder early for unstable pelvis; hemorrhage control is priority. Tile A stable, B rotationally unstable, C rot + vertical unstable. Hemorrhage control: binder, ex-fix, C-clamp, packing, angio. Fixation: anterior plating/ex-fix, posterior SI screws/lumbopelvic. Complications: hemorrhage, urethral/bladder, neuro injury.
Open topicPeri-implant Fractures
Definition: fracture adjacent to fixation device or prosthesis. Differentiate peri-implant vs periprosthetic. Causes: stress risers, osteopenia, trauma. Management: depends on implant stability, bone stock, fracture pattern. Principle: retain stable implant, revise/replace if loose.
Open topicPerilunate Dislocation
Perilunate dislocations and fracture-dislocations are high-energy carpal injuries in which the lunate loses its normal articulation with the surrounding carpal bones — the capitate, scaphoid, triquetrum, and hamate are displaced dorsally while the lunate remains (at least initially) in the lunate fossa of the distal radius. They result from a fall onto an outstretched hand in hyperextension, ulnar deviation, and intercarpal supination, and are classified by the Mayfield progressive perilunar ins...
Open topicPeriosteal Reaction
Periosteal reactions are one of the most underrated signs on a plain X-ray. One look at the pattern tells you whether you're dealing with something benign and slow — or aggressive and urgent.
Open topicPeripheral Nerve Injury — Sunderland Classification
Seddon: neuropraxia, axonotmesis, neurotmesis; Sunderland expands to 5 degrees based on structural disruption. Degree I: conduction block; II: axonal disruption intact endoneurium; III: endoneurial disruption; IV: perineurial disruption intact epineurium; V: complete transection. Prognosis worsens with increasing degree; surgical exploration/grafting typically for IV–V. EMG/NCS guide prognosis and timing; Tinel’s progression marks regeneration (~1–3 mm/day).
Open topicPeriprosthetic Distal Femur Fracture
Lewis–Rorabeck and Su classifications guide treatment; stability of the femoral component is the key decision point. Stable TKA → fixation (locking plate or retrograde nail if intercondylar box permits). Loose TKA → revision arthroplasty with long stem or distal femur replacement in poor bone stock. Biologic fixation with long, locked constructs reduces nonunion/varus collapse. Early ROM; weight‑bearing tailored to construct stability.
Open topicPeriprosthetic Fractures — Classification & Management
Classification guides treatment by considering fracture location, implant stability, and bone stock. THA femur: **Vancouver** (A: trochanteric; B1: around stem-stable; B2: around stem-unstable; B3: poor bone stock; C: distal). TKA periprosthetic femur: **Lewis–Rorabeck** (I: nondisplaced, stable; II: displaced, stable; III: loose component). Principles: fix stable implants; revise loose stems; restore alignment and biology with locking plates/cables/strut grafts or long-stem revision. Risk...
Open topicPeriprosthetic Fractures after TKA — Classification & Management
Incidence rising with aging population and expanding TKA volumes. Common sites: distal femur (supracondylar), tibia (around keel/stem), patella (resurfaced patella). Classifications: Lewis–Rorabeck & Su (femur), Felix (tibia), Ortiguera–Berry (patella). Stable components → fixation; loose components/poor bone → revision with stems/augments ± megaprosthesis. Avoid iatrogenic risk factors (anterior femoral notching, malalignment, osteolysis).
Open topicPeriprosthetic Joint Infection — Principles
Diagnosis uses consensus criteria (MSIS/ICM) combining major and minor criteria. Classify by timing: early (24 mo) — guides biofilm maturity and strategy. Treatment options: DAIR (debridement, antibiotics, implant retention), one‑stage or two‑stage revision; chronic suppression in poor hosts. Principles: radical debridement, exchange modular parts, biofilm‑active antibiotics (e.g., rifampicin combinations for staph). Prevention bundle: laminar flow, antibiotic prophylaxis, skin prep, glycemic co...
Open topicPeriprosthetic Osteolysis — Imaging & Management
Periprosthetic osteolysis = bone loss from wear particle-induced inflammation. Detected on radiographs as radiolucencies, cystic defects; CT useful for mapping, MRI (MARS) for soft tissue. Must exclude infection before labeling aseptic osteolysis. Management: debridement of granuloma, bone grafting, bearing exchange, revision arthroplasty if components loose. Prevention: use of HXLPE, ceramics, optimal component position.
Open topicPerthes Disease — Management
Idiopathic avascular necrosis of femoral head in children 4–10 yrs. More common in boys; often unilateral. Clinical: limp, hip/knee pain, limited abduction/internal rotation. Imaging: X-ray shows increased density, fragmentation, collapse, reossification (Waldenström stages). Management: containment (bracing, osteotomy) to keep femoral head within acetabulum.
Open topicPes Planus - Flat foot
Pes planus (flatfoot) is a deformity characterized by loss or reduction of the medial longitudinal arch of the foot, resulting in hindfoot valgus, forefoot abduction, and altered biomechanics. It may be flexible or rigid, congenital or acquired, and can occur in both children and adults. Most pediatric flexible flatfeet are physiological and asymptomatic, whereas adult-acquired flatfoot is commonly associated with posterior tibial tendon dysfunction (PTTD). Diagnosis is based on clinical examina...
Open topicPhyseal Injuries — Salter–Harris & Ogden
Physis has zonal architecture; hypertrophic zone is weakest and fails in most injuries. Salter–Harris I–V (Slip, Above, Lower, Through, Rammed) with Ogden’s extension (VI–IX). Aim for **anatomic reduction**, especially for SH III–IV to prevent joint incongruity and growth arrest. Consider percutaneous reduction techniques to minimize physeal damage; avoid repeated forceful attempts. Long‑term surveillance for growth disturbance with Park–Harris lines and contralateral comparison.
Open topicPigmented Villonodular Synovitis (PVNS) / Tenosynovial Giant Cell Tumor (TGCT)
Benign proliferative synovial lesion; localized or diffuse type. Common in knee (80%) and hip; presents with pain, swelling, recurrent effusion. MRI: low-signal intensity on T2 due to hemosiderin deposition. Treatment: synovectomy (arthroscopic/open); recurrence common in diffuse type. Targeted therapy: CSF1R inhibitors (pexidartinib) for unresectable cases.
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