Week 4 Flashcards
What four bones are make up the pelvic girdle?
Ilium
Pubis
Ischium
Sacrum
What are the two main ligaments of the pelvis? What structures do they form?
Sacrotuberous and Sacrospinous ligaments
Form the greater and lesser sciatic foramina
What are the important nerves to be aware of that pass through the pelvis? What do they regulate?
Pudendal and Splanchinc nerves - important for control of bladder and bowel
Also the sciatic nerve, which splits into the tibial and common fibular nerves
Describe the blood supply to the hip. How are these affected in a hip fracture?
What condition could result if some of these smaller end arteries become blocked? Amongst others, what medication in particular could precipitate this condition?
From the deep femoral artery arise the medial and lateral circumflex arteries. These form a ring anastomosis around the head and neck of the femur.
Branching off of these circumflex arteries are the retinacular arteries, which are susceptible to damage if the hip is fractured.
The hip is also supplied by the artery of ligamentum teres (which also passes through the ligamentum teres)
Blockage of/damage to the end arteries e.g. through thrombosis, fat embolis etc. can result in avascular necrosis of the head of the femur. Long term steroid use affects fat metabolism and could result in AVN.
Of the gluteal muscles, which is the main abductor?
What test can be performed to assess abductor function?
Gluteus medius, helped by gluteus minimus
Trendelenburg’s Test can be used to detect abductor weakness - when standing on one leg, patient will lean away from leg remaining on the ground.
Which of the hip muscles is the most powerful flexor of the hip?
The iliopsoas, made up of the psoas major and the iliacus
Which nerve supplies the quadriceps (and the rest of the anterior compartment of the thigh)?
What test can be used to assess the function of this nerve?
The femoral nerve
The straigh leg raise can be used to assess this nerve’s function
Which nerve supplies the posterior compartment of the thigh? What is the one exception?
Where can tendons for ACL reconstruction be harvested from?
The tibial division of the sciatic nerve (L5, S1, S2) supplies the posterior compartment of the thigh, except the short head of biceps femoris, which is supplied by the common fibular nerve
Tendons can be harvested from semitendonosus (preferred), and also the patellar tendon (there is more morbidity associated with harvesting from here)
What nerve supplies the adductors of the hip? Pathology of this nerve can lead to referred pain, where?
What range of motion is first lost in hip pathology?
The obturator nerve (L2, L3, L4) supplies the adductors of the hip, except the hamstrings part of Adductor magnus, which is supplied by the Tibial nerve
Pain from the hip can be referred by the obturator nerve to the knee - classic case is slipped upper femoral epiphysis (SUFE), presenting as knee pain in teenagers.
First ROM to be lost in hip pathology is internal rotation
What structures pass through Hunter’s (subsartorial) Canal on their way from the adductor hiatus to the popliteal fossa?
The femoral artery and femoral vein.
Also the saphenous nerve.
What are the two types of cartilage present in the knee joint?
What is the difference between the Medial and Lateral meniscus?
Hyaline cartilage
Fibrocartilaginous menisci
The medial meniscus (MM) is fixed, while the lateral meniscus (LM) is mobile. MM is much more prone to tears (9:1)
The knee contains 4 separate ligaments - what forces do each of them resist?
Medial Collateral Ligament (MCL) resist valgus stress (knock-knees)
Lateral Collateral Ligament (LCL) resists varus stress (bow-legs) and helps to resist external rotation
Posterior Cruciate Ligament (PCL) resists anterior and posterior translation of the tibia
Anterior Cruciate Ligament (ACL) resists internal rotation and anterior translation of the tibia
Genu varum = knock-knees/bow-legs
Bow legs
Genu valgum = knock-knees/bow-legs
Knock-knees
What are the 4 bursae present on the anterior surface of the knee joint?
What condition can result in people who kneel a lot?
- Suprapatellar
- Prepatellar
- Infrapatellar
- Pes anserine
Bursitis (inflammation of the bursa) is common in people who kneel a lot e.g. Housemaid’s Knee
What nerve supplies…
The anterior compartment of the leg?
The posterior compartment of the leg?
The lateral compartment of the leg?
Anterior = deep fibular nerve
Posterior = tibial nerve
Lateral = superficial fibular nerve
What bones make up…
The hindfoot?
The midfoot?
The forefoot?
Hindfoot = calcaneus and talus
Midfoot = navicular, medial, intermediate and lateral cuniforms, and the cuboid
Forefoot = metatarsals and phalanges
What are the components of hyaline cartilage?
Water
Proteoglycans
Chondrocytes
Collagen
What do chondrocytes produce to regulate the ECM?
Collagen
Prostaglandins
Enzymes
What is the only area of hyaline cartilage that receives a blood supply?
The calcified layer, beyond the tidemark
What can lead to defects in articular cartilage?
Briefly describe the healing process of cartilage
Trauma
Atraumatic causes
- osteochondritis dessicans (temporary loss of blood supply to hyaline cartilage, leading to ischaemia and fragmentation
- osteoarthritis
- inflammatory arthritis
Only full thickness injuries heal, i.e. those that pass the tidemark. Hyaline cartilage is replaced with fibrocartilage - has less friction and more prone to wear and tear
Osteochondritis dessicans is more common in very young/adolescents/the elderly.
Adolescence
Can heal or resolve spontaneously. Pinning and reattaching fragmented pieces of cartilage only works in younger patients
What cartilage regeneration techniques are available?
When are these suitable?
- drilling/microfracture - causes bleeding, resulting in a clot and recruitment of chondrocytes
- osetochondral allograft/autograft
- mosaicplasty
- MACI - membrane-induced autologous chondrocyte implantation (very pricey!)
The above are only suitable for small defects, and don’t work in OA, inflammatory arthritis and joint instability.
Worth bearing in mind that some techniques require multiple operations, and some patients (10%) are worse off after surgery
What is the difference in effectiveness between the different articular cartilage regeneration techniques?
No difference in effectiveness! Only difference is cost.
Microfracture is the simplest and cheapest
All techniques will only improve conditions for about 5 years.
What might predispose an indiviual to OA?
Injury
- articular cartilage
- fracture
- joint instability
Malalignment
- Genu varum or valgum
- Fracture malunion
Degenerate meniscal tear
Infection
What are some of the NICE-approved non-surgical treatments for OA?
Lifestyle modifcations - weight loss, exercise, use of a stick, analgaesics etc.
Steroid injections to treat acute flare-ups, but too many can make OA worse!
What are the surgery options like for the treatment of early OA?
Not great…
Washout and debridement is ineffective and only lasts for a couple of months
Osteotomy (breaking and realigning bones) can be useful in varus knee (corrected to valgus to offload pressure), but only has a 70% satisfaction rate (less than total knee replacement) and can affect the success of later knee replacement surgery - 10-20% develop a neuropathic pain
What are the indications for knee replacement surgery?
What’s the prognosis? And how does TKR compare to partial replacement?
Only in older patients with end-stage OA
Younger patients don’t take well to TKR - poorer outcomes and higher rates of failure.
80% feel an improvement, but 1/5 will still suffer with ongoing moderate pain. Expected to last 15-20 years.
Partial replacement is less effective that TKR
Other than dissatisfaction, what other risks are involved with knee replacement?
Deep infection - occurs in 1% of patients and requires multiple operations to correct
Risks of pain, stiffness, DVT/PE and other medical complications (e.g. death during surgery)
Which is the only part of the meniscus to receive a blood supply?
The periphery
The tibia internally/externally rotates on extension and internally/externally rotates on flexion.
The medial/lateral meniscus is under a greater deal of tension
Extension - externally
Flexion - internally
Medial meniscus is under more tension - injuries much more common
(Again!) Which ligaments in the knee resist what stresses?
MCL - resists valgus stress
LCL - resists varus stress
ACL - resists anterior subluxation of the tibia and internal rotation of the tibia in extension
PCL - resists posterior subluxation of the tibia/anterior subluxation of the femur, and hyperextension of the knee
What resists external rotation of the tibia during flexion of the knee?
The postolateral corner - PCL and LCL, along with the popliteus and other small ligaments
Why does the MCL heal more rapidly than the LCL?
MCL receives a blood supply, while the LCL is more like a rope
MCL rupture may lead to…
Valgus instability
ACL rupture may lead to…
Rotatory instability
PCL rupture may lead to…
Recurrent hyperextension or instability going up stairs
Posterolateral corner rupture may lead to…
Varus and rotator instability
What can patients with a bucket handle tear of the meniscus not do?
Fully extend the knee
What is the likelihood of a meniscal tear healing?
Limited healing potential.
Only peripheral 1/3 has a blood supply and therefore can heal.
Radial tears (innermost 1/3) won’t heal
Pain from initial injury may settle and younger patients might heal.
You see a patient with an acutely locked knee, unable to fully extend (a 15 degree “springy block”) and you suspect a displaced bucket handle tear. What do you do?!
Urgent surgery is required as this could be repaired.
If knee remains locked (>6 weeks), the patient could develop FFD (flexion deformity of the knee)
How common are degenerate meniscal tears? What might they signify?
Very common - 20% of over 50s, many of whom are asymptomatic
Could be the first stage of OA development
How are injuries to the ligaments of the knee graded?
Grade 1 - sprain
Grade 2 - partial tear
Grade 3 - complete tear
ACL repair doesn’t work, and instead reconstruction must be performed. What types of graft are available?
Allograft - taken from a donor
Autograft - tendon is harvested from patient
Synthetic graft - usually has a bad track record
What is the rule of thirds when discussing ACL reconstruction?
What % of ACL ruptures result in surgery?
1/3 are able to function well and continue with their normal activities
1/3 can avoid instability, but cannot perform certain activities
1/3 do not compensate, develop instability and cannot return to their sport
40% of ruptures receive surgery
Under what circumstances might surgery be considered for ACL rupture?
What must be kept in mind when considering surgery?
When rotatory instability doesn’t respond to physiotherapy - main reason
Done to protect meniscal repair if this was also damaged
Allows for a more rapid return to sport (debatable). Younger patients seem to tolerate surgery better.
Surgery does not treat pain or prevent development of OA
What is the prognosis after ACL surgery?
Extensive rehab
Some never return to sport
20% failure rate
Graft-donor site morbidity
Stiffness (3%) and infection (1%)
Most have evidence of OA on radiograph after 10 years
What are some of the serious complications associated with knee dislocation?
Injury to the popliteal artery
Injury of the common fibular nerve
Compartment syndrome
What is Deontology?
Is the act right or wrong in itself?
Associated with Immanuel Kant. In medical practice terms, this covers for example the patient’s right to refuse any treatment
What is Consequentialism/Utilitarianism?
Consequentialism - Whether some action is right or wrong depends on the consequences
Utilitarianism - act to maximise the greatest amount of happiness for the greatest number of people
What is Communitarianism/Community Ethics?
Is the act good for everyone that will be affected by the act?
Current ethics is far too individualistic? We should not be merely considering the benefits for a single individual
Modern examples - notifiable disease and vaccination programmes
What are the Four Principles of Biomedical Ethics, as described by Beauchamp and Childress?
Respect for Autonomy
Beneficience
Non-Maleficence
Justice
