Orthapaedics Flashcards
Indications for joint replacement
Degenerative disease
Inflammatory disease
Trauma
Tumour
Vascular disease
Revision of previous replacement
3 types of hip replacement
Cemented
Hybrid
Uncemented
Difference between cemented and uncemented hip replacement
Cemented uses bone cement to fix implant to bone
Uncemented relies on bone in growth onto implant
What substance is used as cement in cemented joint replacements
Poly(methyl methacrylate) - acrylic polymer
How are Uncemented joint implants designed to increase bone ingrowth
Porous or hydroxyapetite covering
How can cement cause damage to tissue
Cause burns as it sets
Which materials for joint replacements have the lowest wear rate
Ceramic on ceramic
Are intra operational fractures more common in cemented or Uncemented joint replacements and why
Uncemented
Forcing prosthesis into too small hole
How long before a pt can bear weight on a cemented or Uncemented hip replacement
Cemented - immediately
Uncemented - 4-6wks
Spinal fusion
2+ vertebrae joined together with screws and bone graft to stabilise vertebral column
Indications for spinal decompression surgery
Spinal stenosis
Damaged IVD
fractured vertebrae
Tumours
3 types of spinal decompression surgery
Spinal fusion - vertebrae are joined together to stabilise and strengthen the spine
Laminectomy - area of bone from vertebrae is removed to relieve nerve pressure
Discectomy - section of damaged disc is removed to relieve nerve pressure
Vertebroplasty
injection of bone cement into the vertebral body in order to relieve pain and / or stabilise the fractured vertebra
Soft tissue orthopaedic procedures
Tendon repair
Tendon transfer
Tendon lengthening
Ligament repair
Ligament replacement
Free muscle transfer
Free muscle transfer
Replacing damaged or destroyed muscle with other skeletal muscle (+ often overlying skin) from elsewhere in body
Which muscles are most commonly used for free muscle transfer
Gracilis
Rectus femoris
Which tendons are most commonly used for ACK reconstruction
Semitendinous tendon
Gracilis tendon
What procedure can improve toe walking
Achilles tendon lengthening
Tendon lengthening
surgically cutting part, or all, of a tendon to create a longer, more functional tendon
Types of poor fracture healing
Delayed
Mal union
Non union
Delayed fracture healing
Failure to consolidate within 1.5x expected time
Fracture Non union
Failure to consolidate within 2x expected time
Fracture Mal union
Misalignment of proximal and distal fragments
Types of fracture Mal union
Rotation
Angulation
Shortening
Translation
2 types of fracture non union
Atrophic
Hypertrophic
Difference between Atrophic and hypertrophic non union
Atrophic - no Blood supply
Hypertrophic - has blood supply
What causes Atrophic non union
Lack of blood supply to bone ends or metabolic conditions
What causes hypertrophic non union
Inadequate fracture stability - bone ends move too much
What type of poor fracture healing leads to ‘elephant foot’ or ‘horse hoof’ appearance
Hypertrophic non union
Osteotomy
Surgical cutting of a bone usually for realignment
Distraction osteogenesis
Bone lengthening
cutting and slowly separating bone using a distractor and allowing the bone healing process to fill in the gap
Reconstructive orthopaedic procedures
Osteotomy
Distraction osteogenesis
4 sources/types of bone graft
Autograft
Allograft
Xenograft
Alloplast
Autograft, allograft, xenograft, and alloplast sources
Auto - pts own tissue
Allo - tissue from another person
Zeno - tissue from an animal
Allo - synthetic material, eg hydroxyapetite
4 processes involved in bone grafting
Osteogenesis
Osteoconduction
Osteoinduction
Osteopromotion
Osteogenesis
Formation/development of new bone cells from graft
Osteoconduction
Physical effect where matrix of graft forms a scaffold which favours outside cells to penetrate the graft and form new bone
(Bone growing on a surface)
Osteoinduction
Chemical process where molecules in graft converts neighbouring cells into osteoblasts
Osteopromotion
Grafted material enhances Osteoinduction
Aseptic loosening
failure of the fixation of a prosthetic component in the absence of infection
Difference between wear and corrosion of a prosthetic
Wear - mechanical process from changes in load distribution and micro motion
Corrosion - electrochemical process of metal degradation
Which areas of bone are most commonly affected by cancer metastases
Spine
Pelvis
Proximal femur
Proximal humerus
Effects of cancer metastasising into bone
Severe pain
Decr mobility
Pathological fractures
Treatment of cancer metastases lesions in bones
Surgical resection
Joint reconstruction w bone graft
Lytic bone metastases
distant tumour deposits of a primary tumour within bone characterised by a loss of bone with the destruction of the bone matrix
