Deformity Correction and Limb Reconstruction (Ilizarov, Osteotomies) MCQs

Orthopedics · 35 free questions with answers & explanations.

1. The Ilizarov principle of 'tension stress' states that controlled, gradual distraction at the rate of 1 mm/day in 4 increments (0.25 mm × 4/day) stimulates:
2. A child has a tibial non-union with a 5 cm bone gap, an infected medullary cavity (history of osteomyelitis), and 3 cm of limb length discrepancy. The most appropriate Ilizarov technique in this complex scenario is:
3. The centre of rotation of angulation (CORA) concept in deformity analysis is used to determine the apex of a bone deformity. When a closing-wedge osteotomy is performed exactly at the CORA, which residual deformity is expected?
4. The principle of distraction osteogenesis (Ilizarov method) is based on the law of tension stress, which states that slow controlled traction on living tissues creates a state of sustained tension that stimulates bone generation. The recommended rate and rhythm of distraction for optimal bone regeneration is:
5. In a patient with a varus deformity of the knee due to medial compartment osteoarthritis, a high tibial osteotomy (HTO) aims to transfer load to the lateral compartment. The ideal target of mechanical axis correction after HTO is:
6. A patient with post-traumatic malunion of the tibia with a combined angulatory and translational deformity requires correction. The center of rotation and angulation (CORA) method is used to plan osteotomy. If the osteotomy is performed at a site away from the CORA, which secondary deformity results?
7. The Ilizarov method of distraction osteogenesis for limb lengthening is based on which biological principle?
8. A 14-year-old boy has a femoral shaft deformity with 22° anterior bow and valgus alignment following malunited fracture. The CORA (centre of rotation of angulation) technique is used to plan the corrective osteotomy. What does CORA represent?
9. In the Ilizarov distraction osteogenesis technique, the optimal rate and rhythm of distraction is:
10. A high tibial osteotomy (HTO) performed for medial compartment osteoarthritis of the knee aims to achieve a post-operative mechanical axis passing through what percentage of the tibial plateau width (from medial to lateral)?
11. The Centre of Rotation of Angulation (CORA) in deformity analysis is important because osteotomy performed at the CORA level:
12. In Ilizarov distraction osteogenesis, the surgical technique of choice for the corticotomy (bone division) to maximise periosteal and endosteal blood supply preservation is:
13. The Ilizarov principle of distraction osteogenesis relies on which biological mechanism?
14. A 10-year-old boy has a post-traumatic leg length discrepancy of 5 cm with angular deformity of the tibia (valgus 15°). The preferred method for simultaneous LLD correction and angular correction is:
15. In a proximal tibial valgus-producing osteotomy (high tibial osteotomy) for medial compartment knee osteoarthritis, the surgical goal is to shift the mechanical axis of the lower limb to what percentage across the tibial plateau?
16. A corticotomy (as opposed to an osteotomy) for distraction osteogenesis with the Ilizarov technique is preferred because:
17. The principle underlying Ilizarov's method of limb lengthening — distraction osteogenesis — is based on which biological concept?
18. In a patient with post-traumatic medial compartment knee osteoarthritis and a varus deformity of 12°, high tibial osteotomy (HTO) is planned. The goal of HTO is to shift the load-bearing axis to the lateral compartment by correcting the mechanical axis. The recommended overcorrection target is to achieve a mechanical axis passing through:
19. Regenerate bone quality during Ilizarov distraction osteogenesis is best assessed by which radiographic criterion during the consolidation phase?
20. The biological principle underlying Ilizarov's technique of distraction osteogenesis is that gradual tensile stress applied across a corticotomy stimulates new bone formation. This process is best described as:
21. A 35-year-old man with medial compartment knee osteoarthritis and 12° varus deformity (mechanical axis deviation to medial compartment) is a candidate for high tibial osteotomy (HTO). The target correction for the mechanical axis post-HTO is:
22. A 14-year-old girl with post-traumatic tibial growth arrest develops a progressive tibial length discrepancy of 6 cm with a 15° angular deformity at the site of physeal damage. The Ilizarov technique applied to correct BOTH the angular deformity and the length discrepancy in a single stage using a circular fixator is best described as:
23. The 'center of rotation of angulation' (CORA) method is used for planning corrective osteotomy. If a corticotomy is performed AT the CORA level for a pure angular deformity, which of the following will result?
24. The Ilizarov principle of distraction osteogenesis relies on which biological phenomenon as its foundation?
25. In Ilizarov distraction osteogenesis for tibial lengthening, the standard distraction rate and rhythm are:
26. A 35-year-old presents with a 12-degree varus deformity of the knee, medial compartment osteoarthritis, and preserved articular cartilage in the lateral compartment. The deformity apex is at the medial tibial plateau. The most appropriate surgical procedure is:
27. Ilizarov's law of tension-stress states that gradual distraction osteogenesis generates new bone formation. The standard distraction rate and rhythm used in clinical practice is:
28. A 14-year-old boy has a 5 cm leg-length discrepancy due to physeal arrest after a childhood tibial fracture. The contralateral limb is normal. The MOST appropriate strategy when predicted adult LLD is confirmed to be 5 cm is:
29. A patient undergoes a high tibial osteotomy (HTO) for medial compartment knee osteoarthritis with varus deformity. The principle underlying HTO is to shift the mechanical axis to unload the diseased compartment. The goal is to correct the limb mechanical axis to pass through approximately:
30. Ilizarov's tension-stress effect states that gradual distraction of living tissue produces metabolic activation and regenerative growth. In distraction osteogenesis, the optimal rate and rhythm of distraction is:
31. A 45-year-old male has medial compartment osteoarthritis of the knee with 8° of varus alignment and a lateral compartment that is preserved. He wishes to delay arthroplasty. The osteotomy designed to unload the medial compartment by correcting the deformity at the level of the tibial mechanical axis is:
32. A patient with a malunited tibial fracture has a 20° anterior angulation deformity at the mid-shaft. Correction osteotomy should be performed at the apex of the deformity. The principle that correction at any level other than the apex creates a secondary translational deformity is described as:
33. A 10-year-old girl has post-traumatic growth arrest of the distal tibia resulting in a 4 cm tibial shortening with 12° varus deformity. The Ilizarov method is planned for simultaneous lengthening and deformity correction. The rate of distraction used in Ilizarov bone transport/lengthening is:
34. The CORA (Center of Rotation of Angulation) concept is fundamental to deformity correction osteotomies. If an osteotomy is performed at a level other than the CORA, which deformity will result after correction?
35. In tibial lengthening using the Ilizarov frame after corticotomy, the 'latency period' before distraction begins is: