A patient presented with chronic knee pain but has no history of trauma. Identify the condition shown in the radiograph below and the appropriate management.

Correct Answer: A. Bipartite fracture patella, X-ray of other knees

Bipartite patella is a developmental anatomical variant, not a fracture, occurring in 0.2–2% of the population. It results from failure of fusion of an accessory ossification centre (usually superolateral pole) during skeletal maturation, typically becoming symptomatic in adolescents and young adults during growth spurts. The key discriminator is chronic knee pain without trauma history—this rules out acute fracture mechanisms. On radiographs, bipartite patella shows a well-defined, smooth-bordered accessory bone fragment with sclerotic margins and no acute fracture line, distinguishing it from traumatic fracture. The management is X-ray of the contralateral (other) knee to confirm the diagnosis: if both knees show identical bilateral accessory ossicles, this confirms the benign developmental variant rather than a unilateral fracture. Most bipartite patellae are asymptomatic incidental findings; symptomatic cases respond to conservative management (rest, NSAIDs, physiotherapy). Surgical excision is reserved for persistent symptoms despite 6 months of conservative therapy. The absence of trauma history and the chronic presentation pattern are pathognomonic for this developmental condition in Indian orthopaedic practice.

Why the other options are wrong

B. Fracture of the upper pole of the patella, Cylindrical cast — Upper pole patellar fractures are acute traumatic injuries requiring a clear history of direct trauma or fall. The absence of trauma history in this case rules out this diagnosis. Cylindrical cast immobilization is appropriate for acute fractures but inappropriate for bipartite patella, which is a developmental variant requiring only symptomatic management. This option confuses traumatic fracture with developmental anomaly. C. Patellar avulsion fracture, TBW — Patellar avulsion fractures occur when the quadriceps or patellar tendon avulses a fragment during forceful knee extension against resistance—always associated with acute trauma. The patient's chronic pain without trauma history excludes avulsion fracture. TBW (tension band wiring) is the gold standard for acute avulsion fractures but unnecessary for bipartite patella. This option misinterprets a developmental variant as an acute traumatic injury. D. Avulsion fracture, interfragmentary screw fixation — Avulsion fractures require acute traumatic mechanism (sudden forceful muscle contraction or direct impact), which is absent in this case. Interfragmentary screw fixation is reserved for displaced acute fracture fragments requiring anatomical reduction. Bipartite patella, being a developmental non-union, does not require operative fixation. This option inappropriately applies acute fracture management to a benign anatomical variant.

High-Yield Facts

Mnemonics

BIPARTITE vs FRACTURE Bilateral = Bipartite (developmental); Fracture = unilateral + trauma history. Check the other knee to confirm. CHRONIC pain = CONSERVATIVE Chronic presentation without trauma = developmental variant = rest, NSAIDs, physio. Acute pain + trauma = fracture = cast/surgery.

NBE Trap

NBE pairs "patellar pathology" with "cast immobilization" to trap students who reflexively apply acute fracture management to developmental variants. The absence of trauma history is the critical clue that this is NOT a fracture requiring operative fixation.

Clinical Pearl

In Indian orthopaedic outpatient practice, adolescents and young adults presenting with chronic anterior knee pain are often incidentally found to have bipartite patella on imaging done for other reasons. Confirming bilateral involvement on contralateral knee X-ray reassures both patient and clinician that this is a benign anatomical variant requiring only symptomatic management, avoiding unnecessary surgery and disability.

_Reference: Bailey & Love Ch. 37 (Knee injuries); Rockwood & Green's Fractures in Adults (Patellar injuries)_