Congenital absence of the patella refers to a condition where an individual is born without the patella ^[1]. It may be bilateral or unilateral ^[2,3]. It is an extremely rare condition and when present mostly occurs as part of syndromes, such as the Nail-patella syndrome ^[4,5], small patella syndrome, trisomy 8 mosaicism, and Meier–Gorlin syndrome ^[6,7]. Limited data are available on congenital absence of the patella [8-10], Individual case reports highlight the rarity of the condition [11-13]. No data on incidence and prevalence is available due to the small number of cases except where the patella was absent as part of a syndrome [14-16].

We are presenting 35-years-old free medically, active soldier referred to the orthopedic clinic from family medicine after noticing abnormal incidental findings on X-rays (Fig. 1-4).

On inquiring him, he doesn’t recall any problem during his childhood and performing his military duties. On clinical examination of the patient, he had characteristic features of patellar absence with prominent femoral condyles and hollow sulcus as per computed tomography (CT) both knees (Fig. 5,6).

He has good quadriceps and hamstring power 5/5. No other abnormalities were detected in his upper and lower limbs. Potential biomechanical adaptations that help to maintain normal gait and joint kinematics in this patient with congenital absence of the patella, specifically mechanisms that prevent knee hyperextension. This may include strengthening or altered recruitment of surrounding musculature (e.g., hamstrings, hip flexors, gastrocnemius), and modified joint alignment or ligament tensioning within normal compare to other studies. Both static postures and dynamic loading scenarios, for example, walking and stair climbing, have been stable movements, which are normally enhance quadriceps efficiency by increasing the moment arm and increased hamstring stress due to compensatory function in absence of the patella (Fig. 5). His blood parameters of liver function test, renal function test, and bone profile and labs are all normal (Table 1). Patient’s hip joints demonstrated a normal range of movement and his ankle joints were also normal. The rest of her musculoskeletal exam was also normal. His cardiovascular, neurological, and abdominal examinations were all normal (Fig. 5). CT chest, abdomen, and pelvis showed no osseous or visceral abnormal. (Fig. 7 & 8).

Congenital absence of bilateral patella occurring in isolation is rare and is usually associated with syndromes. It is even rarer to occur in an asymptomatic active soldier. The most common syndrome associated is Nail Patella syndrome. Other rare syndrome includes Meier–Gorlin syndrome, RAPADILINO syndrome, and Genitopatellar syndrome.

Isolated congenital bilateral patellar absence I asymptomatic serving military soldier has not been described in the English literature before and is exceedingly rare.

Congenital absence of bilateral patella occurring in isolation is rare and is usually associated with syndromes. It is even rarer to occur in an asymptomatic active soldier.