22.Mechanism of action of Methylprednisolone in spine trauma?

Stabilises cell membrane

Neutralises superoxide radicals

limits lipid peroxidation

decreases accumulation of intra-cellular calcium

decreases tissue edema

decreases release of exitatory amines

may increase spinal cord blood flow

[although current literature provides very little evidence for use of MP in spinal trauma, neverthless this was a question asked in practical exam so included here]


23. In tibia shaft fractures what is the acceptable alignment criteria?

these are called traftons's criteria and include

varus- valgus not more than 5 degrees

antero-posterior angulation not more than 10 degrees

rotation not more than 10 degrees

shortening not more than 15 mm

24. Define Non union of bones?

Complete cessation of healing of a fracture, both clinically and radiologically, for a particular location and type of fracture within stipulated time period for given bone and soft tissue injury and would not progress to union unless active intervention is undertaken.

FDA has given a working defination - Non union is established when minimum 9 months have elapsed since injury and fracture shows no visible progressive signs of union for 3 months

AO has given its own defination which is same as FDA with the time period being 6 months.


25. In orthopaedic practice how will you diagnose non union? or on what factors will you base your diagnosis of non union?

Diagnosis of non union is based on following factors - Subjective criteria (Patients assessment of pain at fracture site, Difficulty in weight bearing); Objective criteria (Clinicians assessment of fracture mobility, the amount and extent of it and planes of mobility); Temporal criteria (Passage of time as per the above FDA, AO criteria) and Radiographic Criteria (assessment of union on the radiographs).


26. What are radiographic features of Non union?

Persistent fracture line, sclerosis of the fracture ends, callus may be hypertrophic or atrophic,  radioluecency around the implant.

27. What is Insall Salvati ratio?

Ratio of patellar articular surface to length of ligamentum patellae. Normally, one,if it is more it is patella baja if less it is alta.


28. What is the limitation of Insall – Salvati Ratio?

The measurement of the ligamentum patellae takes tibia tubercle as a reference point. The position of tibia tubercle in not constant and thus the ratio can be more or less not only depending on length of ligamentum but also on position of tibial tubercle.

29. What is Q angle?

The Q angle or quadriceps angle is formed by the quadriceps pull on the tibial tuberosity or centre of patella. It is measured by a line drawn from ASIS to mid point of patella & another line from mid-point of patella to tibial tuberosity. The angle so formed is Q angle.

Normally 9-15°.More in females.


30. What are causes of unilateral genu valgus?

- Rickets

- fracture lateral condyle

- Infection

-IT band contracture

- Hypoplastic lateral condyle


- TUMORS – Osteochondroma, fibrous dysplasia


31. What are the causes of bilateral genu valgum?


-Ehlar danlos syndrome

- mucopolysacchroidosis



- idiopathic


32. Why in renal rickets genu varum deformity is seen?

When renal rickets sets in the child is less than 2 years and has physiological genu varum, thus with progressive weakeing of physis, genu varum is aggravated

In cases with acquired renal rickets, the disease presents late at around 6 – 8 years of age when the limb is in physiological valgus which is then aggravated.


33. Define Mechanical Axis of Lower Limbs?

The mechanical axis of the limb has been defined as the angle between one line drawn from the centre of the femoral head to the deepest part of the femoral notch at the knee, with a second line drawn from the midpoint of the tibial plateau to the midpoint of the inner extension of the tibio-talar joint.


34. Define Legg Calve Perthes disease?

LCPD is a type of osteochondrosis characterised by avascular necrosis and disordered enchondral ossification of primary and secondary ossification centre of femoral head. It is also known as the ‘coronary disease of the hip’


35. Who described LCPD?

It was first described by Weldenstrom [1909], however he suggested it to be a variant of tuberculosis. Legg (boston), Calve (France) and Perthes (Germany) simultaneously described it in 1910 and underlined it as non infectious and an independent entity in itself.

36. what is the mean age of onset of LCPD?

In western countries the age of onset is 6 years, whike in India the mean age of onset is 9 years.


36. What is the blood supply of femoral epiphysis?

Three main sources of blood supply

-          Extracapsular arterial ring

-          Ascending retinacular vessels

-          Ligamentum teres

The first two are branches of the medial and lateral circumflex femoral arteries. The branches of ascending retinacular vessels form a subsynovial anastomotic intra-articular arterial ring at the margin of articular cartilage of the femoral head.

Study of Chung et al in post mortem specimens showed that anterior part of this ring was deficient in males – this may explain higher prevalence in boys.


37. What are types of clinical presentation of LCPD?

LCPD may present in three forms

-Synovitis type – with restriction in range of motion, pain which responds to rest and traction. Restriction of abduction and internal rotation

- Tuberculous type – clinically an radiological appearance of tuberculosis, regains good function of hip with rest and nil weight bearing mobilisation

- Ankylosing type – 10% cases, no clinical symptoms but just a stiff hip with restriction of all movements.


38. What are radiological head at risk sign in LCPD?

These signs correlate with poor prognosis and if 2 or more are seen it is an indication for aggressive treatment.

Easy pneumonic to remember them is ‘GEMS’

G- Gage’s sign

G – Growth plate horizontal

E – Extrusion of the femoral head [lateral extrusion is the most important risk sign]

M- Metaphyseal Cyst/ metaphyseal reaction

S – Speckled calcification lateral to capital epiphysis.


39. What are clinical risk signs in LCPD?

There are four clinical risk signs in LCPD that indicate poor prognosis in LCPD

-Persistent progressive loss of hip range

- increased adduction contracture

- Female gender

- Obesity


40. What is the first radiological sign of LCPD?

Small ossific nucleus with increased medial joint space [compared to opposite side] is the first radiological sign of LCPD.

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