Outline for Quiz #1Section 1: BiomechanicsBackground:- The study of structure and function of biological systems by methods of mechanics- Concerns internal and external forces acting on the bodyo And the effects of these forces- Wide-reaching fieldo Solid and fluid mechanics o Motion sports mechanicso Automobile crash testso Tissue engineering and biomaterials: artificial organs and joints- Orientation of the body:o Proximal – upward, near head Superioro Distal – downward, near feet Inferioro Medial – inward, towards bodyo Lateral – outward, away from bodyo Anterior – forward, towards noseo Posterior – backward, towards buttocksTotal Knee Replacement:- Anatomy of the kneeo Three major components Femur – superior portion Tibia – inferior portion Patella – knee cap- Your quadriceps and tibia are connected by the patella tendon o Three major joints Patello femoral joint Tibio femoral joint Tibio fibula joint – NO ARTICULATION- Other two are more importanto Meniscus tissue Deepens the socket of the tibia and cushionso Cartilage on cartilage articulation Less friction than bone on bone Lubricated with synovial fluid – very slipperyo Stabilizers Static – ligaments (muscle that connects bone to bone)- Primary restraint (medial, lateral, anterior, posterior)Key:Bold: terms to knowItalics: concepts to knowColor: will very likely be on the examo ACL – cross-shaped (X) Primary restraint to anterior subluxation  Tears when you plant your foot and turn too quickly (common in basketball and soccer)- Secondary rotary (rotation) There are 6 degrees of freedom in the knee (x,y,z)- 3 lateral- 3 rotational- Conditions that lead to total knee replacemento Osteoarthritis Types:- Primary (idiopathic)- Secondary – post-traumatic arthritis  Commonality:- More common than hip osteoarthritis - Affects 80% of people older than 75- Same risk in males and females until menopause, then more common in females  Risk factors:- Increasing age- Gender: female- Obesity- Trauma- Infection- Repetitive occupational trauma Symptoms:- Pain- Loss of function- Stiffness- Swelling- Deformity- Crepitus  Treatments:- Non-operative:o Non-pharmacological  Educational methods Weight loss Assistive devices Physical therapy Occupational therapyo Pharmacological NSAIDS Glucosamine sulphate Intra articular Corticoteroids- cortisone shots  Intra articular Hyluronic acid- Operativeo Arthroscopy (arthroscopic debridement) Shave off cartilage o Osteotomy 90 degree unrestricted knee flexiono Knee replacement surgery Partial knee replacement Total knee replacemento Rheumatoid arthritis  Genetic Autoimmune  Dissolves cartilage - Similar symptoms as above, because cartilage wear is similar to dissolving cartilage o Joint Capsule RuptureStability is lost Arthritis is developed if untreated- This is due to a change in load bearing Cartilage is wearing away- Can lead to a joint replacement Even laproscopic, minimally-invasive procedures need to go through the joint capsule- Indications for surgeryo Cartilage breaks down, bones start to rub against each other (painful)o Body spurs from around the joint and ligaments start to weaken - History of knee replacementso Partial vs. total partial: only replace one condyle – the other is still intact total: replaces both condyles. Full tibial and femoral components.o History of total Materials tried- Ivory (started the idea of biocompatibility), nylon, pig muscle, pig fat- Ivory joint hinged with metal or plaster- Metal on plastico Materials used today Stainless steel Cobalt-chromium alloys- Metallosis and failure concerns Titanium  Tantalum Titanium + Tantalum into the trabecular bone (porous, spongey bone)- bone can better integrate into the device  Zirconium UHMWPE (plastic) Ceramic- Not common. Expensive, not strong enough. Cemented- Uses bone cement- For people with low bone density- Not preferred  Cementless- No bone cement – preferred, because if replacement surgery is needed, cement removes extra bone, which is undesirable - Allows for bone-integration- Hybrid: femoral has no cement, tibial uses cementWinner of material combination: metal on plastic- The medial condyle is larger than the lateral- Classificationso Unconstrained (many types) PS – Middle stem in tibial component separating the two condyles- most popular Cruciate retaining – No middle stem- *stem is for posterior function of the ligament  Mobile bearing prosthesis – allows for motion- non-rigid- load-sharing- failure likely – motion of device allows for looseningo Constrained 1 degree of freedom – compensates for lack of dynamic restrainto Unicondylar only replaces one of the two condyles- Criteriao Biocompatibleo Structurally and functionally similar Still has a range of motion and is similarly shaped Not a lot of frictiono Long lasting Appropriate strength, maintains shapeThe less surgeries, the better- Surgicalo Goals: Restore mechanical alignment Preserve the joint line Balance ligaments – must be relaxed for surgery- varus- valgus Normal Q-angle-Quadriceps angle – should be under 20 degreeso Otherwise risk of sports injuries, specifically ACL tears- Angle between the neck of the femur (goes into hip) and other side of the femuro Surgical Procedure Requires sawing of the femur and insertion of the new condyles via drilled holes and peg inserts Tibia also requires drilling down to create scaffold for the bottom componento Robotic More precise incisions Makes for a better-positioned implant Reduce risk of future complicationsHip Arthroplasty- Hip Jointo Components Femoral head (ball)- Can be cemented or uncemented  Acetabulum (socket)-Has a deep socket so that it doesn’t dislocate- Shell and linero Shell: metal bone anchoro Liner: PE for low frictionCan have replacement surgery to only replace the liner Stem-Allows for height adjustment o Rotation – 3 degreeso Types (3): 1) Resurfacing- Just replaces the ball and socket 2) Mini-hip- Has a small stem 3) Total hip- Larger stem- Implanto Surgery – non-ligament sparing because the socket is replacedo Surgery techniques Posterior- Posterior direction of surgery- Need to go through more muscle – invasive  Lateral- Common- Could cause dislocation (abductor muscles) Antero-lateral-