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Orthopaedic Clinic

Tit Bits
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TIT BITS: some small packets of information on topics that are commonly asked off hand during Viva exams


Types of Muscle contractions:


Isometric: Isometric refers to "equal Distance". This mans that the contraction doesn't result in the movement of the joint. Examples include: Pushing on a wall, holding a briefcase or lifting a heavy weight.


Isotonic: Refers to an equivalent force being exerted throughout an entire range of movement. Typical examples include lifting free weights. The goal of this exercise is to ensure that muscle gets worked up during the entire range of motion.


Iso kinetic: Means equal speed. No matter how hard the subject pushes against the machines, the speed of movement remains constant. This allows the person exercising to exert maximal force during all parts of the ROM.



Plyometric Exercise: A functional type of exercise which applies the principle of a brief stretch following a contraction.



Mechanism of injury that lead to fractures:


Direct Injury: Direct blow fractures the bone at site of impact.


Transverse and Oblique fractures: Bending forces.


Spiral Fractures: result of a twisting force.


Compression Fractures: Due to crushing compressive forces.



Types of weight Bearing:


None: 0% body weight.


Toe -Touch weight bearing: up to 20% body weight.


Partial weight bearing: 20 - 50 % body weight.


Weight bearing a tolerated: 50 -100% of body weight.


Full weight bearing: 100% body weight.



Cast Disease:


Muscle atrophy.






Joint stiffness.



Drugs used in osteoporosis:


 Inhibitors of Osteoclasts:


    Biphosphonates (Etidronate, Alendronate)


Stimulators of Bone formation:

    Sodium Fluoride.

    Anabolic steroids.


    Parathyroid hormone.

    Selective estrogen receptor modulators (SERM): Raloxifen, Tamoxifen.




Mechanisms of heating modality used in PT and Rehab:







Superficial heating modalities:


Hot packs.

Heat lamps.

Hot water soaks.

Whirl pools.

Paraffin baths.


Short Wave diathermy (SWD): Heats tissue by exposing it to radio waves produced by a machine that is essentially a short wave radio. Three frequencies are commonly used 40.68, 27.12 and 13.56 M Hz. Energy is delivered by either capacitive or inductive electrodes.


TENS: It is a analgesic modality that applies small electrical signals to the body with superficial skin electrodes. Electrodes may be placed over the peripheral nerves, nerve roots and acupuncture points, as well as proximal to, distal to, over and ( more controversially) contra lateral to the pain site.


Describing a fracture on x ray:


Fracture location.

Involvement Of the bone region: Diaphysis, metaphysic, epiphysis or articular surface.

Fracture line configuration: Transverse, oblique or spiral.

Deformity: Alignment, angulations, and rotation.

Number and location of boney fragments, displacement, direction and distance from normal location, distance between fragments.

Dislocation or effusion of adjacent joint.

Swelling or evidence of soft tissue disruption.





Ankylosing Spondylitis.

Reiters Syndrome.

Psoriatic arthropathy.

Enteric arthropathy.




IDET is a percutaneous procedure designed to treat symptomatic lumbar internal disc disruption, as determined by provocative discography. The procedure employs a navigable catheter inserted into the disc via a large bore needle. The distal portion of catheter incorporates an active electro thermal tip placed in the posterior annulus. The thermal resistance coil generates heat that is directly transferred to the annular tissues from the active tip to modify collagen fibers and coagulate the nociceptors.


Prolotherapy: Injection of a solution for the purpose of tightening and strengthening loose or weak tendons, ligaments or joint capsules. A proliferant (usually 15% dextrose solution) is injected and cause multiplication and activation of fibroblast, which synthesize precursors to mature collagen, resulting in thicker, stronger and tighter connective tissue.



Agents to treat spasticity:


    Phenol (Carbolic acid): 5-6% aqueous solution for adults and 3-5% for children.

    Ethyl alcohol in a concentration of 35-100%.

    Botulinum toxin: Inhibits the release of acetylcholine at the neuromuscular junction.



Orthosis: An external apparatus worn to restrict or assist movement. Three cardinal indications are SAP: support, alignment, protection.



Muscle groups around shoulder:


Prime movers: Deltoid, and clavicular head of Pectoralis Major.

Steering Group: Subscapularis, Supraspinatus, and Infraspinatus.

Depressor Group: Sternal head of P. Major, Teres Major and Minor, Latissimus Dorsi.


Portals of Knee Arthroscopy:


Anterolateral: 1 cm lateral to the lateral border of patella and 1 cm above the joint line.


Anteromedial: 1 cm medial to medial border of patella and 1 cm above the medial joint line.


Posteromedial: Junction of posteromedial edge of femur and posteromedial edge of Tibia.


Superolateral: 2.5 cm lateral to superolateral corner of the patella.



Cryotherapy: The primary rationale is the initial vasoconstriction that assists in control of swelling and edema that typifies acute injuries. Various modalities that are used are: Ice massage, cool spray, cold whirl pool.


Physiological effects of cooling:


Local increase in tissue temperature.

Decrease in the metabolism.


Decrease in the blood flow.

Decrease in the nerve conduction velocity.

Decrease in venous and lymphatic drainage.

Decrease in muscle spindle activity.

Decreased formation of and accumulation of edema.


Indications: Decrease the bleeding, Spasm, edema, fever, burns, Herpes infection.




Has a thermal and non thermal effect:


Non thermal effects:

    Chemical reaction: Stimulates the chemical activities in tissue.

    Biological reaction: Alters the permeability of cell membrane and increases 

    the  transfer of fluid and nutrient to the cell.

    Mechanical reaction: Deforms the molecular structure and if the intensity is

     great may even cause cavitations.

    Acoustic Streaming.



Uses: Decrease the pain.

          Facilitate the healing process by increasing the circulation.

          Decrease the scar tissue.


Frequency used: Depends on skin thickness, usually 0.5- 2.0 mw/cm square.



Interferential therapy: Two different frequencies are used. The medium frequency that has a value in reducing the skin resistance but doesn’t decrease the pain or stimulate the muscle is combined with an effective frequency (1- 200 MHz) so that together they can achieve a desired penetration as well as the desired effect.



Effects of chondroitin sulfate and glucosamine:


    Stimulate the metabolism of chondrocyte and synoviocytes.

    Inhibit degradative enzymes.

    Reduce fibrin thrombi in periarticular vasculature.

    Glucosamine stimulates the biosynthesis of glycososaminoglycans and

    hyaluronic  acid, the back bone needed for formation of proteoglycans  

     found in the structural matrix of the joints. This hyaluronic acid suppresses

     the anticatabolic effects of interleukin 1 in chondrocyte cell cultures.



Visco supplementation:


    Offer anti inflammatory and antinociceptive properties by stimulation of hyaluronic acid synthesis.

    Dampen the response of the pain fibers in the joint membrane by coating the pain receptor.

Provides lubricating and cushioning properties.

Decrease the cartilage elasticity and compressibility.


Triage classification:







Indications for prophylactic fixation for impending long bone fractures:


1. Cortical bone destruction of 50% or more.

2. Lesion of 2.5 cm or more of proximal femur.

3. Pathological avulsion of lesser trochanter.

4. Persisting stress pain despite irradiation.


Indications of Epiphysiodesis:

1. If there is sufficient growth left to effect a correction.

2. If the patient is growing on or above the 50 the centile and will be taller than average.

3. If discrepancy is 6 cm or less- with increasing discrepancy the potential for error is    



Interpretation of DEXA scores:


T score- The score in references to a young adult population and is a measure of the absolute risk of fracture.


Z score: Those with age matched control group, indicates relative risk.


1.0-2.5: Osteopenia.

< 2.5: Osteoporosis.

< 2.5 +: Indicates severe osteoporosis in presence of evidence of stress fractures.



Rickets: Defective mineralization of immature skelton.






   Others: Anti convulsants, NF, Wilson disease. Liver disease.


Alternative Classification for cause:



    Defective 25 alpha hydroxylation: Liver diseases, anti convulsants.

    Defective 1 alpha hydroxylation: Renal disorders, nephrectomy, 1- alpha hydroxylase    



Biochemical tests for rickets:

1. Serum calcium and phosphate concentration.

2. Serum alkaline phosphate.

3. Osteocalcin ( Gla Protein): more specific marker of bone formation.

4. Parathyroid hormone activiserum assay of COOH terminal fragment.

5. Vit D activity: measuring 25 – HCC concentration.

6. Urinary calcium and phosphate excretion.

7. Urinary hydroxyl praline excretion.

8. Excretion of pyridinium compounds and telopeptides derived from collagen cross links; it is a sensitive marker for bone resorption.


Pathology in ricket: Inability to calcify the intercellular matrix in the deeper layers of the physis. The proliferative zone is as active as ever but the cells instead of arranging themselves in an orderly column, pile up irregularly, the entire physeal plate increases in thickness, the zone of calcification is poorly mineralized and bone formation is sparse in the zone of ossification. The new trabeculae are thin and weak and with joint loading the juxta epi- meta physis becomes broad and cup shaped.


Away from the physis the changes are mostly of osteomalacia. Sparse islands of bone are lined by wide osteoid seams, producing ghost trabeculae that are not very strong. The cortices are also thinner than normal and may show new or old stress fractures.


X Rays:


Thickening and widening of the growth plate.

Cupping of metaphysic.

Bowing of diaphysis.


Osteomalacia X rays:

Loser’s zone.

Biconcave vertebrae.

Trefoil pelvis.

Spontaneous fractures.





Autosomal recessive.

Deficiency of lysosomal enzymes.

Glycosoaminoglycans: - Dermatan sulfate, Keratan sulfate, heparin sulfate and chondroitin sulfate which are normally degraded by lysosomal enzymes are accumulated in lysosomes with an impaired function of cells, tissues and organs and are found increased in urine.

Common features include: Enlargement of organs, abnormal appearance, boney abnormalities, hearing, vision, CVS function, restriction of joint mobility. Mental retardation in Hurler syndrome.


Skeletal Features:

    Skull: Macrocephaly, J shaped cella, Thick clavarium.

    Chest: wide oar shaped ribs, wide clavicle.

    Spine: Oval and hook shaped vertebrae.

    Pelvis: Over constriction of iliac bodies, wide iliac flare, dysplasia of femoral capital     

      epiphysis, Coxa valga.

    Long tubular bones: Irregular diaphyseal modeling, periosteal cloaking.

    Bone structure: Osteopenia.

    Short tubular bones: Shortening and widening.


Types of MPS:
I – Hurler Syndrome (Gargolyism)

II – Hunters (X Linked)

III – San Fillipo.

IV – Morquio.

V – Morceau.


Treatment of MPS in general:

    Prenatal diagnosis.

    Genetic counseling.

    Gene replacement.

    Deformity corrections: genu valgus/ varus etc.

    Spine stabilization.




    Development of bone that is laid down in the cartilage is at fault.

    The membranous bone is found to develop normally.

    Clinical features:

      Normal size body, small stature with proximal segment affection most.

     Trident hands.

     Head enlarged, face broad, root of nose depressed, prognathism.

     Normal intellect.

     Long regular kyphus, Spinal stenosis.


Histo pathological appearance: Absence of cartilage proliferation, loss of normal palisade. Ossification is very slow.


Diagnosis is based on: Epiphyseal line is indistinct but with normal ossification ( in contrast to Rickets)

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