Overview Flashcards
What is orthopedics
is the medical discipline devoted to the musculoskeletal (MSK) system.
Orthopedic surgery is the medical science concerned with restoring and preserving the normal function of the MSK system.
What are 3 functions of the MSK system
Support
Protection
Movement
What are the 6 elements of the MSK system
Bone – provides support
Cartilage – provides smooth surface for articulating bones
Intervertebral Disks – sustains and distributes loads
Muscle – contract to create movement
Tendons – connect muscle to bone
Ligaments – connects two bones
Cells of the bone
Osteoblasts make new bone
Osteoclasts remove necrotic bone
What are the 2 types of bone
Cortical bone – less porous, denser outer portion of bone.
Cancellous bone – more porous, trabecular bone – surrounded by cortical bone
What are 2 reasons there might be a fracture?
Fx’s occur when a single momentary load on a particular bone exceeds the tolerance of that bone – usually the result of trauma
Fx’s may also occur from repeated loading that leads to bone fatigue and failure – which is a stress fx.
What are the 5 steps of fracture healing
Impact Inflammation Soft callus formation Hard callus formation Remodeling
Impact- Fracture Healing
application of force/energy resulting in fracture.
Inflammation- Fracture Healing
Hematoma formation at fx site.
Granulation tissue replaces hematoma
Fibroblasts make collagen
Osteoclasts remove necrotic bone
Soft callus formation- Fracture Healing
After inflammation soft callus forms uniting the fracture fragments.
Hard callus formation- Fracture Healing
Soft callus becomes hard callus and the bone appears clinically healed.
Remodeling- Fracture formation
Final stage of fx healing – bone is already healed and now is reshaped back to normal shape.
What is ORIF
open reduction and internal fixation
What happens during surgery for Fx?
First the surgeon exposes the fx, cleans things up, reduces the fx and temporarily maintains reduction while applying the appropriate fixation device. At the conclusion of surgery immobilization is required so the bone heals in the right position.
What happens after surgery?
This usually means a cast application – often uni or bi-valved (split) to allow for post-operative swelling.
Once swelling reduced a more appropriate cast for weight bearing activities may be applied.
Fx’s having undergone ORIF heal more quickly than conservatively Rxed fxs – but are more at risk for infection, complications of anesthesia or surgery.
Factors that influence Fx Healing
Site of the fx Blood supply Age & nutritional status Apposition of fx fragments Adequate immobilization of fx site Presence of soft tissue interposed at fx site Infection
What 2 things can happen when a Fx fails to heal properly
Non-union
Malunion
Non Union Occurs during?
There is a poor blood supply (elderly are more at risk).
Poor nutritional status
Inadequate immobilization
Soft tissue interposed between fx fragments.
Presence of infection or dead bone (sequestrum)
Treatment for Non Union
Most technologically advanced means of dealing with a non union is using the Ilizarov method.
This involves the application of an external fixator.
External fixator can then be adjusted and bones distracted or compressed.
Bony regeneration occurs at the rate of 1mm per day.
what is malunion of a Fx
Bone healing has occurred but with an unacceptable degree of angulation, rotation or shortening.
In the L.E. leg length discrepancies of
> 1” are not tolerated well.
Ilizarov method can be used here as well.
Complications of Fx
Nerve Damage
Closed fx’s are less likely to have complete transections of nerves and so more likely to recover function.
Open fx’s are more likely to be associated with nerve transections.
Infections
Signs and Symptoms of Fx complications
Fever/increased pain/redness
Purulent drainage
Culture of pus yields organism – usually staph
Stress Fractures
Repeated load stresses to a weight bearing bone (often the tibia) results in micro injuries that cause resorption.
This causes intrinsic weakening of the bone stress fx.
Often occurs in athletes who increase their activity too abruptly.
Also occurs in individuals who go from sedentary to highly active lifestyles
Clinical Presentation of Stress Fractures
Long hx of achey pain in affected areas (tibia, distal fibula, metatarsal).
There may be a precipitating event.
Pain is further aggravated by activity.
Pain occurs with both loading and unloading of bone.
Pts may have deformity or swelling.
Radiographic findings for stress fractures
Plain x-rays may be normal.
X-rays may show some subtle cortical disruption or evidence of prior bone healing.
Bone scan is usually more helpful.
CT and MRI are expensive and may be of limited value.
Treatment for Stress Fractures
Relative rest to affected part.
Use of splints if needed.
In some cases casting is required.
Amenorrheic women may benefit from BCP’s to reduce risk of osteopenia.
Best thing is prevention – this can be accomplished by counseling athletes, coaches, trainers, parents etc on avoiding improper training techniques.
What is a joint
The articulation where two bones meet.
Joints allow movement of one bone on another.
What is cartilaginous joint?
minimal movement – cartilage between bony surfaces; i.e., symphysis pubis, vertebral bodies (intervertebral disk), AC joint, sternoclavicular joint.
Fibrous Joint
immovable, i.e., skull sutures
Synovial Joint
Synovial joint – freely moveable, articular cartilage, synovial fluid/joint capsule, ligament
Ball and Socket: hip and shoulder
Hinge joint: fingers, elbow
Condylar: knee, TMJ
What is articular cartilage
Avascular tissue composed of chondrocytes and an organic matrix.
Articular cartilage is found at the end of bones where two bones come together to form a joint.
Cartilage is a “one-dimensional” substance.
It only does one thing but does it very well.
It distributes joint loads and allows movement of joint surfaces with minimal friction and wear
Repairing Articular Cartilage
The body does attempt to repair articular cartilage with new hyaline cartilage.
The result of that repair is fibrocartilage – which is less than ideal for joint surfaces.
If cartilage defects extend through the entire thickness to the calcified plate at the bony junction then there is no capacity for repair.
Tendons
attach muscles to bone transmitting load from muscle to bone and creating movement.
Ligaments
attach bone to bone – contribute to the stability of joints and define the motion of one bone against another.
First Degree Sprain
Minimal fiber failure
Minimal pain
No detectable joint instability
Usually heals in a few days without sequelae.
Second Degree Sprain
Partial tear or stretching of ligament.
Causes severe pain w/swelling.
Results in some (minimal) joint instability.
Pain persists for weeks after injury and through much of the healing process.
Can take 6 to 12 weeks for complete recovery
Instability may be difficult to assess initially in the awake pt due to pain and guarding.
3rd Degree Sprain
Ligament completely or nearly completely ruptured.
Severe pain at the time of injury but little or no pain afterwards.
The joint is unstable.
Will take 3, 4 or even 6 months to recover.
Does the ACL heal itself
does not self repair. The presence of synovial fluid in the knee disrupts healing.
The knee does not do well with extensive immobilization so reconstruction is recommended
Healing of Ligaments/ Tendons
Healing events initiated by inflammatory response w/PMN infiltrate, fluid exudation, capillary budding – lasts ~ 3 days.
By 4th day fibroplasia occurs w/accumulation of fibroblasts from surrounding tissues.
Within 3 weeks a mass of granulation tissue forms surrounding the injured tissue
Intervertebral Disks made of 2 components
Sustain and distribute loads and prevents excess motion in the spine.
- An inner soft nucleus pulpous
- An outer thick fibrous tissue called the annulus
It is the interaction of these two components that allows the spine to handle compressive, shear and rotational forces.
Older individuals are more susceptible to disk herniation due to 2 factors.
Nucleus pulposus dries out reducing it’s ability to handle stress.
The annular bands weaken and the nucleus pulposus can rupture out.
The disks are also subject to collapse increasing the risk of compression fx’s
All multi trauma pts need to be assessed by the ABC principle. A=
airway control – do not hyperextend, hyperflex or rotate the neck when there is any question of a C-spine injury. Use jaw thrust or chin lift to maintain airway control. C-spine films will be needed to r/o fx.
All multi trauma pts need to be assessed by the ABC principle B=
Breathing – is pt breathing – are there chest injuries – PTX, tension PTX, HTX, pulmonary contusion.
All multi trauma pts need to be assessed by the ABC principle C=
Circulation – control hemorrhage, check hemodynamic status, address and Rx shock. Remember pts can lose 1 – 2 units of blood into a thigh with a closed femur fx.
multi trauma D=
Disability – what is pts neurological status, level of consciousness (use Glasgow coma scale). Record all baseline findings and do serial exams. Assess motor and sensory function.
multi trauma E=
Expose patient – do not miss occult injuries because you did not disrobe pt. Cut pts clothes off to minimize moving pt till complete assessment is done. Log roll pt to check posteriorly. Look for lacerations, contusions, swelling, bony or soft tissue deformity.
Pts w/long bone fx’s (esp mult fx’s) watch for fat embolism.
Fat globules released into bloodstream
Occurs 12 to 48 hrs after injury
Often pt is a young adult
Clinical presentation for fat embolism
SOB Restlessness or agitation Confusion (may only be mild) Fever/tachycardia Hypoxemia on ABG’s w > pCO2 Sometimes CXR can be helpful showing infiltrates
Treatment for fat embolism
Respiratory support to correct hypoxemia.
Some will use IV steroids
Use of anti-coagulants which may reduce risk of pulmonary edema and intravascular clotting.
What is compartment syndrome
Compartment syndrome results from increased pressure in a closed space leading to neurological or vascular compromise.
The compartment involves bone and fascia.
Often in the anterior tibial region or the forearm.
What can happen if compartment syndrome goes untreated?
Unrecognized compartment syndrome can lead to significant and irreversible nerve damage.
Untreated it can lead to muscle damage, necrosis, infection and even amputation.
Pts can get C.S. from poorly fitting (too tight) casts.
Some factors that contribute to compartment syndrome
Increased transmural pressure across arterial wall exceed intra arterial pressure thereby compromising circulation.
The ischemic process promotes increased capillary permeability which results in intracompartmental edema and further increased pressure, which accelerates the cycle of pressure and edema.
Epidemiology of Compartment syndrome
The majority of compartment syndromes occur from trauma.
Nearly 50% of all cases of C.S. arise from fx’s of the tibia (closed>open).
C.S. can also arise from ortho surgery, vein harvesting for CABG, improper OR positioning, or improper cast/splint application.
Reperfusion of an ischemic extremity can C.S.
Average age of individuals who get C.S is 30
More common in males.
Older persons may be protected by having smaller “hypotrophic” muscles.
Women somewhat protected for same reason.
Older people may also be protected due to relatively higher BP’s.
Should obtain hx of anti-coagulant use or clotting problems as these can predispose to CS.
Exertional Compartment Syndrome
Results from the combination of muscle hypertrophy and the associated edema/swelling that occurs with exercise within a small compartment.
This places undue pressure on sensitive soft tissue structures like arteries and nerves.
The result is exertional pain or claudication.
With cessation of activity the pain resolves
How is diagnosis made for compartment syndrome
Diagnosis is made by primarily by hx
Have pt exercise to reproduce pain, if pain goes away w/rest and then recurs when you ask them to resume exercise it is most likely exertional compartment syndrome.
After exercise see if pt has pain w/passive motion (toes and dorsiflexion of foot); may also have some mild weakness and slight paresthesia
Tx of exertional compartment syndrome
Rest and more gradual onset of training.
If there is difficulty making a definitive dx the pressure in the affected compartment can be measured at rest and with activity.
Intractable pts can be Rxed w/surgery (fasciotomy).
6 P’s for clinical presentation of compartment syndrome
Pain Pressure Pallor Paresthesia Paralysis (late sign) Pulselessness (late sign)
Hallmark of C.S
C.S. is a crescendo of pain that is out of proportion to the level of injury AND unrelieved by narcotic analgesics.
Clinical Signs that are often less dramatic
Severe and relentless generalized burning pain.
Decreased light touch
Decreased pin sensation
Loss of 2 point discrimination
Diagnosis of Compartment Syndrome
Cornerstone of diagnosis is a high index of suspicion for the problem so you must be thinking of CS.
Intracompartment pressure can be measured in different ways (needles, catheters).
Lab tests can be used but many of the markers like CPK do not help w/early detection.
Tx of Compartment Syndrome
Goal of Rx is to reduce pressure, restore blood flow, thereby minimizing tissue damage or loss of function.
Any external devices should be removed; ie casts (bivalve or remove), occlusive dressings removed.
Elevate limb to the level of the heart – this maintains good venous return without compromising arterial flow.
Use of ice is contraindicated due to it’s vasoconstrictive affect.
Complications of fasciotomy
Pts will need a second procedure to close the fasciotomy, and none of these pts get good cosmetic results.
Infection can occur post op.
Pts can develop problems w/calf function.
Foot drop, decreased sensation can occur
Outcomes of Compartment Syndrome
Delays of more than 12 hours in Rx often result in permanent damage and even amputation.
Timely intervention provides immediate relief and prevents further tissue damage.
