22. Bone, joint and Tendon Reconstruction Flashcards
What is osteoarthritis caused by?
Degeneration of articular cartilage and underlying subchondral bone
What impacts does OA have?
Huge financial burden on society - bloody old people
- 95% surgical volume
- 1-2% GDP
OA is greatest mobility disability of all medical conditions
What is the main treatment for OA?
Joint reconstruction / replacement, (Athroplasty)
How long does it take an Athroplasty to restore a joint back to full strength?
Months or years!
What are some side effects of Knee Arthroplasty?
Blood clots (15%) Blood clots in lung Urinary infections Leg length difference Pain + stiffness Loosening of prosthesis Knee infection Nerve injuries
What are some side effects of hip Arthroplasty?
DVT + pulmonary embolism Dislocation Leg length inequality Persistent chronic pain Loosening of prosthesis Fracture Metal sensitivity Nerve injuries
What are the post operative effects of Knee athroplasty?
90% = increased ROM 0-110 degrees
25% loosening of prosthesis @ 10 yrs
How can dislocation be prevented after hip replacement?
Dont cross legs
Sleep with pillows between legs
Do not bend over 90 degrees
What is the average lifespan of a prosthesis?
12-15 yrs
What is a bone or bone substitue Graft/Implant?
Surgical procedure replacing missing bone with material from patients own body or an artificial substitute
What is a bone graft/implant used to treat?
Complex fractures
Large defects
What are the 4 types of bone substitutes?
1) Autologous + allogenic bone grafting
2) Calcium based chemical bone
3) Ceramic and polymer based
4) Steel based
What requirements should a bone graft satisfy in order to promote osteoregeneration?
1) Osteogenecity - MSCs, osteoprogenitors etc
2) Osteoinductivity - growth factors (BMP)
3) Osteoconductivity - Carrier scaffold for new bone
What is the current gold standard bone grafting treatment?
Autologous bone grafts
Stimulates regeneration at non-union site
What are some limitations associated with autologous bone grafts?
Availability Donor site morbidity Donor site pain Risk of infection Variable fusion success rates
What is surgical fusion?
Surgical technique used to join two or more vertebrae
- Reduce pain due to movement of vertebrae
Uses bone graft to augment surgery
How long does it take surgical fusion to heal?
3 months
What bone is commonly used in autologous graft of bone?
Iliac crest
Provides stem cells
What two types of bone can be used in autologous bone Grafts?
Cortical
Cancellous
What are the characteristics of cortical bone in relation to autologous bone grafts?
Low osteogenic potential
Barrier to vascular ingrowth and remodeling
Cortical bone loses strength during incorporation
Super strong
What are the characteristics of cancellous bone in relation to autologous bone grafts?
Lacks compresive strength
Has greater conductivity, accelerates fusion mass
What is the most common type of autologous bone graft used?
Cancellous bone
Where is bone sourced in allograft bone grafts?
Cadaveric bone
Available in desired configuration
Avoids morbidity of donor site complications
What are the disadvantages of allograft bone grafts?
Delayed vascular penetration Slow bone formation + fusion Accelerated bone resorption Delayed graft incorporation Increased infection rate Lack of histocompatibility
What is distraction osteogenesis?
Surgery using healing property of bone for reconstruction of skeletal deformities and lengthening of long bones
What is the process of distraction osteogenesis?
Fracture created
Ends of bone moved apart (distraction phase)
New bone forms in gap
Expands volume of surrounding tissues
What are the applications of distraction osteogenesis?
Congenital and developmental deformities Post traumatic injuries - growth plate fractures - Bone defects Infections + diseases After tumours Short stature and cosmetic lengthening
What are two types of bone lengthening surgeries?
Ilzarov Surgery = brutal
Fitbone surgery = involves nail which extends
What does the Anterior Crucial Ligament (ACL) do?
Prevents anterior translation and medial rotation of tibia in relation to femur
What does ACL rupture result in?
Impaired stability of knee
Risk meniscal injury
Increased risk of early regenerative disorders
Increased risk of cartilage damage
Can torn ACLs heal?
Not with conservative management
What is the primary treatment for ACL rupture?
Autologous tendonous tissue is most popular method for reconstruction
What are some common sources for ACL autograft?
Patellar tendon = za best
Hamstring tendons
Iliotibal band
Quadriceps tendon
What is the current gold standard for ACL reconstruction autografts?
Patellar tendon
168% greater strength than native ACL
What are the advantages of patellar tendon bone autograft?
High tensile strength
Permits bone-to-bone union at insertion sites
Does not sacrifice another significant stabilizer tendon of the knee
What are some disadvantages of patellar - ACL reconstruction?
Donor-site morbidity Increased scar formation Increased risk of patellar tendonitis/rupture Risk of patellar fracture during harvest Post-op patellar tendon shortening
What are the two types of tendon in the hamistring tendon, and what is the strength of them in ACL reconstruction?
Gracilis tendon alone = 49% of native ACL
Semitendinous = 70% of native ACL
What are the advantages of hamistring tendon ACL replacement?
Low incidence of donor-site complications such as pain
Faster, easier and significantly smaller wound
What are the disadvantages associated with ACL reconstruction?
Longer period required for tendon-to-bone fixation
Initial tensile strength of graft may not be sufficient to achieve post-op stability
Inferior strength to original tendon
Weakening of quads
What are some cadaveric sources of allograft ACL reconstruction?
Patellar tendon
Anterior tibialis tendon
Achilles tendon
Fascia lata
What are the advantages of allograft tendon reconstruction?
No-donor site morbidity Cosmetically better outcome No size limitation Shorter operation time Decreased incidence of post op morbidity e.g. stiffness due to scar formation
What are the disadvantages of allograft tendon reconstruction?
Disease transmission Host immune rejection Delayed incorporation Alteration of mechanical properties secondary to sterilization Cost
