2. Chapter 6 -Injuries to the Lower Extremity Most common due to application of large loads. Important because of the role on the lower extremity in locomotion

3. Hip Anatomy n Ball & Socket (3D) n Ligament support n Iliofemoral n pubofemoral n ischiofemoral n ligamentum teres n Joint capsule: labrum

4. Hip Muscles

5. Hip fractures n High energy forces n falls n car accidents n pelvic (side impacts) n high mortality rates n Femoral neck fractures n > 250,000 n women 3 times likely to get fracture

6. Hip fractures n Young people: high energy impacts n Mechanism n direct impact n lateral rotation of leg n Stress fractures femur n Dynamic models of falls n impact forces 3-10 kN

7. Hip Luxation (dislocation) n Not common: hip stability n High forces n Most cases posterior dislocation n Car accidents: dashboard n Anterior inferior dislocation n 10-20% of hip dislocation n Force abduction n Abduction, flexion and ext. rotation (obturator) n Hip retroversion (toe-in) n Congenital dislocation (infants)

8. Thigh injuries n Three muscular compartments n anterior n medial n posterior n Quadriceps contusion n blunt trauma n extensive hematoma n swelling n increase muscle weight n loss of strength n Myositis Ossificans Ant. Post. Medial

9. Femoral fractures n High energy trauma n car & motorcycle and or pedestrian accidents (78%) n Classified by location, configuration and level of comminution n Dangerous near epiphyseal plates

10. Femoral fractures n Gunshot fractures affected by bullet diameter, velocity, weight, shape, and tumbling n Low-velocity n splintering n High velocity or close range shotgun blasts n More soft tissue damage n Torsional loading n young skiers n high skill level (risk)

11. Hamstring n Excessive tension applied to the muscle n eccentric action n Predisposing factors: n fatigue n muscle imbalance n lack of flexibility n lack of warm up n Biarticular muscles n bicep femoris n MTJ

12. Knee anatomy n Three joints n Tibiofemoral joints n Patellofemoral joints n Double condyloid n flexion/extension n rotation n Poor joint cavity n Meniscus n connect to joint capsule and MCL and sometimes with ACL n Lateral: loose attachment

13. Knee Anatomy n Strong ligament support n collateral lig: resist valgus and varus loading n ACL: two bundles, restrict anteriot motion of tibia, valgus, varus, rotation n PCL: two bundles, restrict posterior motion of the tibia, limits hyper flexion n Patella: mechanical advantage n PFJ huge loads when knee is flexed

14. Knee Anatomy

15. Knee Injuries n ACL sprain: more common than PCL n Mechanism: n valgus loading and ext tibial rotation (cutting movements) n hyperextension and internal tibial rotation (landing from jumps/rotate) n MRI triad: ACL rupture, osseos lession of terminal sulcus, and bone or soft tissue.

16. Knee Injuries n ACL & Skiers n backward fall n Anterior drawer mechanism n Phantom boot n back of skis levers flexed knee into internal rotation n ACL and females ?

17. Knee Injuries n PCL lower incidence of injuries n half of cause due to direct trauma car accidents n Sports n Mechanism n unrestrained occupant thrown against dashboard n fall on flexed knee with plantar flexed knee n force knee flexion n force knee hyperextension n quick rotation

18. Knee injuries n Unhappy triad: valgus- external rotation n ACL n MCL n Medial meniscus damage ?

19. Knee Injuries n Meniscus: n weight bearing n shock absorption n stabilization n rotational facilitation n Full extension n 45-50% of the load n 90 o flexion n 85% load n Laterally: 70% of the load 30% AC

20. Knee Injuries n Screw home mechanism: medial rotation at full extension n Mechanisn n flexion or extension and rotation n tensile loading of medial meniscus n bucket-handle tear n High incidence sports n soccer, shot put discuss, skiing

21. Knee injuries n MCL and LCL sprains n Forced varus or valgus loading n Overuse n breaststroke kick

22. Knee injuries n KEM: knee extensor mechanism n quads n PFJ and tendon n Difference forces in the quad tendon and patellar ligament n Depend on Knee angle n Contact force n Patellar tracking n Q angle n Congruence

23. Knee Injuries n Jumper’s Knee n Patellar tendon pain n Chondromalacia n degeneration of the retropatellar AC n Tendon Rupture n >40 years n previous microtrauma

24. Lower Leg Injuries n Four muscle compartments n Anterior n lateral n sup and deep posterior n Compartment Syndrome n fluid accumulation as a result of acute or chronic exertion n can affect vascular and neural function n Ischemia n Fascia adaptations n Fasciotomy

25. Lower Leg Injuries n Tibial stress syndrome: Inflammatory reaction of the deep fascia n Mechanism n chronic overload n can lead to periostitis n common in runners n multifactor

26. Lower leg injuries n Stress reaction: bone with evidence of remodeling but without actual fracture n Stress fracture n 50% occur on the tibia n runners: middle and distal third n jumpers: proximal fractures n dancers midshaft

27. Lower leg injuries n High energy fractures n car accidents: direct impact n skiing: torsional and boot fractures n Baseball bats

28. Foot & Ankle injuries n Most complex areas in the human body due to large number of muscle, ligaments and bones n Ligaments n deltoid: eversion n ATFL: restrict inversion n CFL n PTFL n 26 bones n Achilles tendon

29. Foot & Ankle injuries n Arches n Longitudinal n medial n lateral n Transverse n Absorb and distribute loads during weight bearing n Supported by bones, muscles, plantar ligaments and plantar fascia

30. Foot & Ankle injuries n Achilles tendon: largest and stronger n forces = 10 times BW n Injuries n peritenitis n bursitis n multifactorial etiology n training n malaligments n trauma n footwear

31. Foot & Ankle injuries n Tendon rupture n degeneration n Men 30-40 years n Blood type (O) n Mechanism n sudden dorsiflexion n rapid change in direction n excess tension on taut tendon n taut tendon struck by object

32. Foot & Ankle injuries n Plantar Fasciitis: inflammation of the plantar fascia involving microtears of partial rupture of the fascia n Repetitive loading compressing the plantar fascia (1.3- 2.9 BW) n Factors n lack of flexibility n lack of ankle strength n overtraining n poor mechanics n leg length discrepancies n over pronation

33. Foot & Ankle injuries n Ankle sprains: most common injuries n Irregular talus & stability n plantar flexion: unstable n Involve ankle and subtalar joint n 85% inversion sprain (supination sprains) n ATFL-CFL-PTFL n Sometime deltoid (taut in plantar flexion)

34. Foot & Ankle injuries n Eversion sprains (pronation) less common n Fractures malleolus n Deltoid ligament n Tibia and fibula separation (high forces)

35. Foot & Ankle injuries n Lisfranc n Low energy: tripping or bumping n High: falls, crashes, object drop n Axial loading foot in extreme plantar flexion or dorsiflexion n Violent twisting n Turf toe n damage to capsule and ligaments of 1st MP joint