1. Injuries of the knee and leg Acute knee ligament injuries - valgus stresses are resisted by the = * superficial and deep layers of MCL. *semimembranosus tendon. * POL posterior oblique ligament –poster medial part of the capsule. *cruciate lig. ( ACL, PCL ). Note= at 30 degrees of knee flexion, the MCL is the primary stabilizer.

2. 2 The varus stresses are resisted by = The iliotibial band. The LCL. The popliteus tendon, the capsule and arcuate lig. =also called the posterolateral structures. Note = the iliotibial band and LCL, are the primary stabilizers to varus stress between full extension and 30 degrees of flexion, however, as flexion increases, the LCL relaxes and the postero lateral structures come into play to provide additional stability.

3. 3 * the cruciate lig.s Provide both AP and rotary stability. they also help to resist excessive valgus and varus angulation. *both cruciate lig.s have a double bundle structure. - ACL = has anteromedial band which is tight in flexion. and posterolteral band which is tight in extension. -PCL = has anterolateral band which is tight in flexion. and posteromedial band which is tight in extension

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7. 7 Mech. Of injury = -Most lig.s injuries occur while the knee is bent, i.e when the capsule and lig.s are relaxed and the femur is allowed to rotate on the tibia. -The damaging force may be a straight thrust ( like a dashboard injury forcing the tibia backwards), or -More commonly, a combined rotation and thrust as in football injury. -The medial structures are most often affected but if the injury involves a twist in addition to valgus stress in a weight bearing knee, then ACL injury may occur. -It is important to recognize that these injuries are seldom unidirectional, they often involve more than one structure.

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11. 8 Clinical features= -the knee is painful and usually swollen, and in contrast to meniscal injury, the swelling appears almost immediately. -tenderness is most acute over the torn lig. note = the findings can be somewhat perverse, - with complete tear the patient may have little or no pain, whereas with a partial tear the knee is painful. - swelling also is worse with partial tears, because haemorrhage remains confined within the joint, with complete tear the ruptured capsule permits leakage and diffusion. - with partial tear, movement is painful, while an abnormal movement of complete tear is often painless.

12. 9 Note= MCL tear usually occurs at its femoral attachment, while LCL tear usually occurs at its fibular attachment. -knee stability is examined by different stress tests= *stressing the tibia anteriorly on femur =for ACL exam. (anterior drawer test, lachman s test ). * stressing the tibia posteriorly on femur= for PCL exam. (posterior drawer test). *valgus and varus stresses to examine lateral and medial structures respectively. * some other tests for rotary instability,e.g. pivot shift test for antero lateral rotatory instability. note = sometimes, if these stressful tests are painful,then we can do them under local or general anesthesia.

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14. 10 Imaging= - x-ray = It may show avulsed fragment of medial femoral condyle, the tibial spine or the head of fibula. -stress film, under anesthesia sometimes necessary. -MRI = to distinguish partial from complete tears. Arthroscopy = main indications are = 1-for reconstruction of cruciate lig. Tears in those individuals who would benefit. 2-to deal with other internal injuries e.g. meniscal tears. Note= arthroscopy is contraindicated in cases with severe tears of collateral lig.s as fluid extravasation will lead to compartment syndrome in the calf.

15. 11 Treatment = - sprains and partial tears = * the intact fibers splint the torn ones and spontaneous healing will occur. *active exercise is advised from the start,and it is facilitated by aspirating a tense effusion,applying ice- packs and sometimes by injecting local anesthetic drug. This is to prevent adhesions. *the patient usually return to sports training by 6-8 weeks.

16. 12 -Complete tears = *isolated MCL tears = a long cast –brace is worn for 6 weeks, and thereafter graded exercises are encouraged *isolated LCL tears = are rare, and if diagnosed then,can be treated as isolated MCL tears. *isolated ACL tears = - we do reconstruction for professionals. - if tibial spine is avulsed, then it is usually fixed by arthroscopy even in non –professionals. - physiotherapy is very important. (Before and after op.) *isolated PCL tears = in professionals need reconstruction and in others usually non –operative treatment is used. Note= if later assessment shows instability then do reconstruction in( ACL or PCL injuries). *combined injuries = here, reconstruction of ACL,or PCL alone,will obviate the need for collateral lig.s treatment. Complications = 1 – adhesions 2- ossification in the lig 3- instability.

17. 13 Dislocation of the knee = -it Occurs only by severe violence, as in RTA. -The cruciate lig.s and one or both collateral lig.s are torn. + neurovascular injury is possible. -Clinical features = -Deformity and swelling of the knee, bruising,pain,tenderness and loss of movement. -Neurovascular examination is mandatory. -X-ray =can show the dislocation and any associated injury. -Arteriogram may be useful sometimes.

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19. 14 Treatment= - reduction under anesthesia is urgent, by pulling directly in the line of the leg, but hyperextension is avoided because of danger to the popliteal vessels. -vascular injury need immediate repair, and here try to repair all the torn lig.s and capsule at the same time. Complications = Early = neurovascular injury. Late = 1- joint instability 2- stiffness.

20. 15 Fracture of the patella = -patella is a sesamoid bone in continuity with the quadriceps tendon and the patellar lig. ( patellar tendon). -there are additional insertions from the vastus medials and lateralis into the medial and lateral edges of the patella. -the mechanical function of the patella is to hold the entire extensor strap away from the centre of rotation of the knee, thereby lengthening the anterior lever arm and increasing the efficiency of the quadriceps. -the key to the management of patellar fractures is the state of the entire extensor mechanism. -if the extensor retinacula are intact, active knee extension is still possible, even if the patella itself is fractured.

21. 16 Mech. Of injury = 1- direct injury = usually a fall onto the knee causes either undisplaced crack or a comminuted (stellate) fracture. 2-indirect injury = e.g. When someone catches the foot against a solid obstacle and, to avoid falling, contracts the quadriceps muscle forcefully. this is a transverse fracture with a gap between the fragments. Clinical features = -the knee is swollen, painful and tender. -abrasion or bruising over the front of the joint. -sometimes a gap can be felt. X-ray = will show transverse, longitudinal, polar or comminuted (stellate) fracture types. -note= bipartite patella = has smooth,regular line, at supralateral corner, and is usually bilateral.(congenital).

22. 17 Treatment = 1-undisplaced or minimally displaced fractures = -aspiration of haemarthrosis. -a plaster cylinder holding the knee straight for 3-4 weeks meanwhile, quadriceps exercises are practiced every day. 2-comminuted (stellate) fracture = -if the fragments are not severely displaced, then a hinged brace is used, with exercises. - if the fragments are severely displaced, then there is serious risk of damage to the patellofemoral joint, so patellectomy may be the treatment. 3-displaced transverse fracture= operative treatment by tension band principle.

23. 18 Acute dislocation of patella=(traumatic type) -because the knee is normally angled in slight valgus, there is natural tendency for the patella to go laterally when the quadriceps muscle contracts. -lateral deviation of the patella during knee extension is prevented by a number of factors = 1- the intercondylar groove has high lateral edge. 2- the force of extensor muscle contraction pull it firmly into the groove. 3- the medial patello femoral lig. With vastus medialis. 4- medial patellomeniscal and patellotibial lig. So, usually, a considerable force is required to cause patellar dislocation. However, if there is shallow groove, high seated patella or lax lig.s, genu valgum, tibial torsion, then dislocation is not that difficult.

24. 19 Mech. Of injury= -While the knee is flexed and the quadriceps muscle is relaxed, the patella may be forced laterally by direct violence, this is rare. -More often it is due to indirect force, sudden, severe contraction of the quadriceps while the knee is stretched in valgus and external rotation, e.g. in sport. -Clinical features = -Patient collapses and unable to straighten his, her leg, stand, or walk. -Knee is swollen ( haemarthrosis). -Deformity is obvious, but sometimes misleading because the medial condyle may be prominent and mistaken for the patella. --x-ray =will show the dislocation, and the possible associated osteochondral fracture ( occurs in 5 % of cases).

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26. 20 Treatment = - urgent reduction with or without anesthesia by pushing the patella medially, while straightening the leg. -sometimes, we need to aspirate tender haemarthrosis. -if there is severe medial joint bruise, then this may reflect serious underlying soft tissue damage, which may needs surgical repair to avoid future recurrence of dislocation. -immobilization by spica cast for 2-3 weeks, then quadriceps exercises started. -operative treatment needed for associated osteo-chondral fracture, or intraarticular dislocation. complication = -patients treated non-operatively for a first time dislocation,have a 15 – 20 % chance of having further dislocations.

27. 21 Tibial plateau fractures = Mech. Of injury = 1-varus or valgus force combined with axial loading e.g fall from height. 2-the result of a car striking a pedestrian ( bumper fracture). Classification = Schatzker classification = 1-a vertical split of the lateral condyle. 2-a vertical split of the lateral condyle combined with depression of an adjacent load bearing part of the condyle. 3-depression of the articular surface with an intact condylar rim. 4-fracture of the medial tibial condyle. 5-fracture of both condyle. 6-combined condylar and subcondylar fractures.

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29. 23 Clinical features= -The knee is swollen, deformed, with bruising, it feels doughy because of haemarthrosis. -assess the distal neurovascular function. -assess knee lig.s injury. X-ray = -plain films, AP,Lat. And oblique. -stress views under anesthesia for lig. Injury may needed. -CT sometimes needed.= to show fragment extension and degree of displacement.

30. 24 Treatment = -conservative treatment can be used and gives a well- functioning knee, but residual angulation is not uncommon. -surgical treatment may produce good and rapid results. -undisplaced fractures = trearted with skeletal traction with early physiotherapy for 2-3 weeks, then cast- bracing and partial Wt. bearing for the next 4-6 weeks, until healing. -displaced fractures= treatment of choice is ORIF, followed by early mobilization and physiotherapy. If ORIF is contraindicated then treat it as above (conservatively). -complications = early =1-neurovascular inj. 2- knee lig. Inj. 3-CS. late = 1-joint stiffness 2-deformity 3-O.A.

31. 25 Fractures of tibia and fibula = -because of its subcutaneous position, the tibia is more commonly fractured, and more often sustains an open fracture, than any other long bone. Mech. Of injury= - A twisting force ( indirect injury ), causes a spiral fracture of both leg bones at different levels,( low energy injury) -An angulatory force produces transverse or short oblique fractures, usually at the same level. ( high energy injury ).

32. 26 Note = the behaviour of these injuries, and therefore the choice of treatment, depends on the following factors = 1- the state of the soft tissue. 2-the severity of the bone injury. 3-stability of the fracture. 4-degree of contamination. Clinical features = -examine for soft tissue damage, severe swelling, and tenting of the skin is very important. -neurovascular examination is mandatory. (compartment syndrome ). X- ray = will show the site, type and displacement of the fracture.

33. 27 Treatment = The main objectives are = 1-to limit soft tissue damage and preserve ( or restore in case of open fractures) skin cover. 2-to prevent or at least recognize a compartment syndrome. 3-to obtain and hold fracture alignment. 4-to start early weight bearing ( load promotes healing) 5-to start joint movements as soon as possible. - In open fractures = 1- antibiotics 2- debridement 3-stabilization 4-rapid soft tissue cover 5-rehabilitation.

34. 28 - in closed fracture= 1- if the fracture is undisplaced = a full length cast from upper thigh to metatarsal necks is applied with knee slightly flexed and the ankle at right angle. - displacement of the fibular fracture, unless it involves the ankle joint, is unimportant and can be ignored. 2- if the fracture is displaced = - It is reduced under G.A, with x-ray control, alignment Must be near perfect,( no more than 7 degrees of angulation ), and rotation absolutely perfect. - then full cast is applied, + exercises, and after 4 – 6 weeks, cast is changed to be below knee cast, or functional brace. - unstable fractures can be treated by ORIF from the start. - failure of conservative treatment needs ORIF. ( plate or nail)

35. 29 Complications = Early = 1-vascular injury = popliteal,ant. Or post. Tibial arteries. 2-compartment syndrome. 3-infection. Late = 1-malunion, 2- delayed union, 3- non union. 4-joint stiffness, 5 –osteoporosis, 6- regional complex pain syndrome.

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37. Student self assessment Write C for the correct answer(s) and W for the wrong answer(s) = 1-Varus stresses in the knee joint are resisted by iliotibial band. 2-The knee swelling is worse with complete ligamentous tears than partial tears. 3-Posterior drawer test is used to examine ACL injuries. 4-In acute knee dislocation, neurovascular examination is mandatory. 5-Minimally displaced patellar fractures are treated with plaster cylinder holding the knee straight for 3-4 months.

38. Assess your attention in the lecture Answers= 1- C 2- W 3-W 4-C 5-W

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