T&O Flashcards
What structures are cut through during the posterior approach to the hip joint?
Skin, subcut fat, gluteal fascia, glut max, short external rotators, hip joint capsule
What nerves are at risk during a posterior approach to the hip joint?
Sciatic and superior gluteal
What is the surface marking of the lateral cutaneous nerve of the thigh as used for nerve blocks?
It passes beneath the inguinal ligament approximately 2cm inferior and medial to the ASIS
Describe some of the approaches to the hip joint.
Lateral: over the GT through the skin, adipose, fascia lata, trochanteric bursa, glut med and min and the hip capsule.
Posterior: skin adipose, fascia lata, glut max, short hip rotators, hip capsule
Anterior: incision between the sartorius and the TFL
How long should you give thromboprophylaxis after a hip replacement?
28 days
How long should you give VTE prophylaxis after a knee replacement?
14 days
Explain the garden classification of hip fracture.
- undisplaced, incomplete #
- undisplaced, complete #
- partially displaced, complete #
- completely displaced, complete #
What are the signs of a serious ligament injury?
Rapid swelling over 1-2 hours
Haemoarthrosis
Large effusions that cause limited movement
Bony avulsions
Localised tenderness
What is the typical mechanism of a meniscal injury?
Rotation of the tibia in a flexed, weight bearing knee.
Medial is 20x more common due to the laxity, typically causes a vertical tear in the anterior or posterior horn.
What are the features of a meniscal injury?
Locked knee
Haemarthrosis
Joint line tenderness
Clicking of the joint
What are the features of an extensor apparatus tear of the leg?
Unable to SLR or extend knee
Swelling or bruising
Palpable gap
What is the management of an injury to the extensor apparatus of the leg?
Muscle tear = conservative
Tendon rupture = surgical repair
Vertical patella fracture = conservative
Transverse patella fracture = ORIF with tension wiring.
What is the gustillo-anderson classification used for?
Open fractures.
Describe the levels of a gustillo-anderson score.
Type 1: wound <1cm with minimal contamination or muscle damage
Type 2: wound 1-10cm with moderate soft tissue injury
Type 3a: wound >10cm with adequate tissue for flap coverage. Contaminated/
Type 3b: required rotational/free flap coverage. May have periosteal stripping.
Type 3c: has a vascular injury
Weakness of what muscle causes claw toes?
Interosseous and lumbrical muscles (which normally extend the interphalangeal joints).
What joint deformity do you see in Hammer toes?
Hyperextension of MTP
Flexion of PIP.
What is Morton’s neuroma?
Plantar or digital neuroma affecting the plantar nerve between the 3rd and 4th metatarsal.
What are the functions of the bone?
Supports the body and facilitates locomotion.
Protects organs.
Produces blood cells and immune cells
Regulates calcium
What hormones act upon the bone?
Calcitonin: causes increase osteoblast function and increased bony uptake of calcium.
Vitamin D: causes increased osteoclast function and release of Ca
PTH: causes increased osteoclast function and release of Ca
Growth hormone: stimulates bone growth
Gluco-corticoids: reduce bony matrix
Thyroid hormone: cause increase osteoclast function
What is the main constituent of bone?
35% organic matrix
65% inorganic matrix which is mainly made up of calcium hydroxyapatite.
What are the cells of the bony matrix?
Osteoprogenitor cells: derived from mesenchymal stem cells and form osteoblasts.
Osteoblasts: build bone
Osteoclasts: derived from hemopoietic progenitor cells which then act to reabsorb bone. They have multiple nuclei.
Osteocytes: mature bone cells, derived from osteoblasts. Control fluctuations of Ca and Phosphate.
What is the periosteum?
This is a layer of fibrous tissue that is attached to the bone by Sharpey’s fibres.
It contains the blood vessels via its cambral layer and also acts as attachment for muscles and ligaments.
What are the two types of bone?
Woven (immature, irregular and disorganised bone)
Lamellar (regular, orderly arrangement of collagen fibres in weight bearing forces that gradually replace woven bone).
How do bones develop?
- Via direct ossification (such as ribs and clavicle)
- Chondrocytes produce hyaline cartilage which forms a template for endochondral ossification.
What are the zones of the physis?
- resting zone (on epiphyseal side)
- proliferative zone
- Hypertrophic zone of maturation
- Provisional calcification (on the metaphyseal side)
What are the two methods of bone healing?
Primary: healing by direct union with no callus formation. In this osteoblastic bone formation occurs directly between the fragments.
Secondary: healing via callus formation when the bone ends are not well aligned.
What are the steps of secondary bone healing?
- Haematoma formation: this seals off the fracture site.
- Inflammation: haematoma provides a framework for the influx of inflammatory cells which activate the osteoprogenitor cells. This occurs during the first 1-7 days.
- Soft callus stage: lasts 2-3 weeks. Uncalcified tissue provides anchorage of the bone ends but no structural support.
- Hard callus stage: lasts 3-4 months. The activated progenitor cells deposit subperiosteal woven bone and chondroblasts deposit cartilage which undergoes endochondral ossification.
- Remodelling: woven hone is replaced by Lamella bone.
What is Wolff’s law?
The lamellar bony canals form in the direction of mechanical stress.
What is malunion?
This is bone healing in a sub-optimal position causing a deformity.
What is non-union?
This is failure to reach bony union by 9 months or no evidence of any healing for 3 months.
What is delayed union?
This is no union by 6 months.
What factors may delay bone healing?
Patient factors:
- Smoking
- Alcohol
- Obesity
- Malnutrition
- Immunosuppression
- PVD
- Anaemia
- Diabetes
- Age
Injury Factors:
- Infected wound
- Soft tissue damage
- Local ischaemia
- Instability
- Poor technique
- Pathological #
Why should you be cautious when giving NSAIDs in a post-operative fracture fixation?
NSAIDs are COX inhibitors and therefore they may interfere with the inflammatory stages of bone healing.
What are the different types of joints?
Fibrous: no cavity. The bones are joined by fibrous tissue. (examples - cranial sutures, syndesmosis, gomphosis).
Cartilaginous:
Primary (Synchondroses): bone meets hyaline cartilage: immovable.
Secondary (symphysis): Bones have an articular surface covered with fibrocartilage (slightly movable).
Synovoal: fluid filled capsule allowing movement.
What are the differences between rheumatoid and osteoarthritis clinically?
Rheumatoid is an inflammatory arthritis, worse on waking, relieved by NSAIDs, may have systemic signs or symptoms, can have a familial element. Get soft tissue swelling. warm and red joints, with raised ESR, raised CRP, low Hb, and +ve antibodies.
Osteoarthritis is a mechanical condition, worse on exercise, and relieved by simple analgesia.
There will be no systemic symptoms. They get bony swellings with normal inflammatory markers, normal Hb, negative antibodies.
What are the differences between RA and Osteoarthritis on imaging?
Both cause joint space narrowing.
Osteoarthritis causes: osteophytes, subchondral sclerosis, subchondral cysts
Rheumatoid causes: marginal erosions, periarticular osteoporosis, soft tissue changes, normally symmetrical and may get subluxation deformity.