Rehabilitation of Ligamentous Knee Injuries (ACL)

Prof. Dr. Nasr Awad’s lecture (PTPTPhysical therapy, or physical therapist.General meaning, not from the slides 406, Physical Therapy for Sport Injuries) covers the anterior cruciate ligamentACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides (ACL): its anatomy and biomechanics, the mechanism of injury and risk factors (especially in females), diagnosis (mainly MRIMRIMagnetic resonance imaging: a scan that uses magnets and radio waves to show soft tissues such as ligaments.General meaning, not from the slides signs), non-operative vs operative treatment and graftGraftTissue used to replace the torn ligament.General meaning, not from the slides choices, and a phase-by-phase rehabilitation protocol from prePREProgressive resistive exercise: strengthening with gradually increasing resistance.General meaning, not from the slides-operative care to return to sportRTSReturn to sport.General meaning, not from the slides, with modifications for concomitantConcomitantHappening or done at the same time as something else.General meaning, not from the slides procedures. The last section is the course’s ACL 1 high-yield exam-question sheet (41 questions). Facts that come only from that sheet are marked (exam sheet).

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Learning objectives

By the end of the lecture the student should be able to:

1. Understand the basic anatomy, function and biomechanics of the ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides.
2. Explain the mechanism of ACL injury.
3. Discuss ACL injury risk and how to prevent it.
4. Discuss the findings of stress testsStress testA test that applies a controlled force to a joint to see how much the ligaments let it move.General meaning, not from the slides for the cruciate injuries.
5. Differentiate between operative and non-operative treatment of ACL injuries.
6. Formulate a proper plan of treatment based on patient presentation and stage of operation.

Each objective on the slide carries a programme-outcome code (for example “a1-Prog.A9”). These codes are left out here.

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ACL anatomy

Role and bundles

• The ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides is the main stabilizer of the knee for athletic pivotal activities.
• It has two bundles: the anteromedial bundleAnteromedial bundleOne of the two bundles of the ACL (AMB). It is slack in knee extension and taut in flexion. (AMB) and the posterolateral bundlePosterolateral bundleOne of the two bundles of the ACL (PLB). It is slack in knee flexion and taut in extension, and gives more rotational stability. (PLB).
• It is enveloped into the synovial membraneSynovial membraneThe thin lining of a joint that produces the lubricating joint fluid.General meaning, not from the slides of the knee joint, which by definition places the ligament intra-articularIntra-articularInside the joint.General meaning, not from the slides but extra-synovialExtra-synovialOutside the synovial cavity: inside the joint but not bathed in the joint fluid.General meaning, not from the slides. The ACL is intra-articular and extra-synovial (exam sheet: same fact).

Origin and insertion

• Origin (femur): the medial side of the lateral femoral condyleFemoral condyleOne of the two rounded bumps at the lower end of the thigh bone (femur) that sit on top of the shin bone.General meaning, not from the slides, at the posterior part of its medial surface.
• Course: an oblique course through the intercondylar fossaIntercondylar fossaThe notch between the two femoral condyles at the lower end of the thigh bone, through which the ACL runs.General meaning, not from the slides, distal–anterior–medial, to the insertion at the tibial eminenceTibial eminenceThe raised ridge in the middle of the top of the shin bone, between the tibial spines.General meaning, not from the slides.
• Insertion (tibia): the area between the medial and lateral tibial spinesTibial spinesThe two small bony points (medial and lateral) on the top of the shin bone.General meaning, not from the slides.

Size

• Width: 7 mm to 12 mm.
• The ligament fans out toward its insertion on the tibia; the narrowest diameter is in the midsubstanceMidsubstanceThe middle part of a ligament, between its two attachment ends.General meaning, not from the slides area.
• Intra-articular length: between 28 and 31 mm.
• The attachment sites on the tibia and femur have a fairly small isometric centerIsometric centerThe attachment point where the ligament length stays nearly constant as the knee moves.General meaning, not from the slides.
• Articular length 25–35 mm, approximately 3 cm (exam sheet).

The slide (13) gives 28–31 mm and the exam sheet gives 25–35 mm (about 3 cm). Both are kept. In the question bank the sheet’s value is the keyed answer, with the slide’s value in the explanation.

The “central pivot”

• The ACL and PCLPCLPosterior cruciate ligament: the knee ligament that crosses the ACL inside the joint and stops the shin bone sliding backward.General meaning, not from the slides are closely intertwined and are called the “central pivotCentral pivotThe name the lecture gives to the ACL and PCL together, because they are closely intertwined..”
• An injury to either ligament disrupts the function of the joint and may lead to late degenerative arthritisDegenerative arthritisWear-and-tear arthritis, where joint cartilage gradually breaks down.General meaning, not from the slides.

Tensile strength

• Reported ultimate failure loadUltimate failure loadThe greatest pulling force a ligament can take before it breaks, measured in newtons (N).General meaning, not from the slides: 1750 N. Some reviews report 2200 N, and both are accepted (exam sheet).
• Young cadaver specimens were stronger than the older ones.
• The speed of the force applied to the ligament affects the type of tear.
• Slow, twisting, low-velocity injury (as in skiers) may elongate the ligament, then “it ruptures up to 30%”. There may be a partial rupture of the anteromedial bundle, leaving the posterolateral bundle intact, or vice versa. A slow-velocity injury may elongate the ligament and progress to partial rupture (exam sheet).

Slide 17 is written as a chain of arrows (skiers → may elongate the ligament → it ruptures up to 30% → partial rupture of one bundle). The “up to 30%” is kept exactly as written.

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Function and biomechanics

Both bundles resist anterior tibial displacement

• Both bundles resist anterior displacement of the tibia relative to the femoral condylesFemoral condyleOne of the two rounded bumps at the lower end of the thigh bone (femur) that sit on top of the shin bone.General meaning, not from the slides.
• The anterior bundle gives more resistance when the knee is flexedFlexionBending a joint.General meaning, not from the slides; the posterior bundle gives more resistance when the knee is extendedExtensionStraightening a joint.General meaning, not from the slides.
• The AMBAnteromedial bundleOne of the two bundles of the ACL (AMB). It is slack in knee extension and taut in flexion. is slack in extension and the PLBPosterolateral bundleOne of the two bundles of the ACL (PLB). It is slack in knee flexion and taut in extension, and gives more rotational stability. is slack in flexion, but there is a continuum between the two, so some portion of the ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides remains fairly taut throughout the range of motionROMRange of motion: how far a joint can move.General meaning, not from the slides.
• Rotational stabilityRotational stabilityHow well the knee resists twisting (rotation) of the shin bone on the thigh bone.General meaning, not from the slides is thought to be provided to a greater extent by the posterolateral bundle than by the anteromedial one.

Exam sheet: the anteromedial bundle is more resistant in flexion; the posterolateral bundle is more resistant in extension.

Slide 19 says “anterior bundle” and “posterior bundle”; slides 20–21 use AMB and PLB. They are the same two bundles.

The text of slide 24 runs off the bottom edge of the slide and ends at “than by the anteromedial”. “Bundle” is implied.

ACL strain graph (slide 22)

• The graph plots ACL strain (%) (axis up to 14%) against knee angle in degrees (about −10° to 120°) for the AMB mean (solid line) and the PLB mean (dashed line).
• Read off the curves: the PLB strain is highest at full extension and falls steeply as the knee flexes, staying low from about 45° onward. The AMB strain stays moderate through mid-range and rises again toward 120° of flexion. The two curves cross at roughly 20–30° of flexion.

ACL strain during rehabilitation activities (slide 23, Figure 11-20)

The bar chart ranks activities by the strain they put on the ACL (bar scale 0–4.5). Highest to lowest, with approximate bar lengths read off the chart:

• No bar is drawn for: isometric quads at 60° and 90°, simultaneous quads and hams at 60° and 90°, and isometric hams at 30°, 60° and 90°.
• Caption (Fig. 11-20): various activities are routinely prescribed to improve muscle strength and joint function after ACL tear or reconstruction. The graph shows the magnitude of strain on the ACL during them. It is currently unclear how much strain can be detrimental to an already damaged ACL or a healing graftGraftTissue used to replace the torn ligament.General meaning, not from the slides.
• Exam sheet: an isometric quadriceps contraction at 15° of knee flexion produces high ACL tension.

Quadriceps force and anterior tibial translation (Figure 11-36)

• A. With the knee close to full extension, a forceful quadriceps contraction is capable of inducing an anterior tibial translation.
• B. Once the knee is flexed to greater than 60°, little to no anterior translation occurs.
• The diagram appears twice in the lecture (slide 46 in the risk factors, slide 119 in the rehabilitation section). It is shown once, with slide 119.

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Mechanism of injury

Non-contact injuries

The proposed non-contactNon-contact injuryAn injury that happens without a direct blow from another player or object.General meaning, not from the slides mechanism (slide 27, panels a–d):

1. (a) An unloaded knee.
2. (b) ValgusValgusAngulation where the lower part of the limb points away from the midline. At the knee it is the inward collapse (knock-knee direction).General meaning, not from the slides loading is applied: the MCLMCLMedial collateral ligament: the ligament on the inner side of the knee that resists the knee being pushed inward.General meaning, not from the slides becomes taut and lateral compression occurs.
3. (c) This compressive load, plus the anterior force vector from quadricepsQuadricepsThe large muscle group on the front of the thigh that straightens the knee.General meaning, not from the slides contraction, causes a lateral femoral posterior displacement (because of the posterior slope of the lateral tibial plateauTibial plateauThe flat top surface of the shin bone that forms the lower half of the knee joint.General meaning, not from the slides). The tibia translates anteriorly and rotates internallyInternal rotationTurning a limb inward, toward the midline.General meaning, not from the slides, resulting in an ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides rupture.
4. (d) After the ACL is torn, the primary restraint to anterior translation of the tibiaAnterior tibial translationThe shin bone (tibia) sliding forward relative to the thigh bone (femur).General meaning, not from the slides is gone. The medial femoral condyleFemoral condyleOne of the two rounded bumps at the lower end of the thigh bone (femur) that sit on top of the shin bone.General meaning, not from the slides is also displaced posteriorly, resulting in external rotationExternal rotationTurning a limb outward, away from the midline.General meaning, not from the slides of the tibia.

• Exam sheet: the non-contact mechanism is landing with knee valgus, hip flexionFlexionBending a joint.General meaning, not from the slides and internal rotation of the hip.

The sheet says “hip flexion”; slide 45 says women land with less knee and hip flexion (see Risk factors). Both are kept. In the question bank the sheet’s wording is the keyed answer.

Panel labels on the slide: (c) “Posterior translation of lateral femur (IR of tibia)”; (d) “Posterior translation of medial femur (ER of tibia)”.

Contact injuries

• A common mechanism in football or hockey is a blow to the outside of the knee when the knee is flexed and rotated.
• This initially injures the medial collateral ligament (MCL), and then, with further valgus, the ACL is torn.
• Slides 28 and 30 carry the same text. Exam sheet: the important contact mechanism is a lateral blow to the knee with the knee flexed and rotated, and the ligament injured first is the MCL.

In brief

• The body and knee must be in the correct position, the quadriceps must contract strongly enough to subluxSubluxationA partial dislocation: the bones shift out of their normal position but stay in contact.General meaning, not from the slides the tibia, and the hamstringsHamstringsThe muscle group on the back of the thigh that bends the knee.General meaning, not from the slides fail to protect against the anterior subluxation.
• Can this be prevented? Perhaps, by neuromuscularNeuromuscularRelating to the nerves and muscles working together to control movement.General meaning, not from the slides, proprioceptiveProprioceptiveRelating to the sense of where the joints are and how they are moving.General meaning, not from the slides training, some injuries may be prevented.

Take-home message

• Emphasize hamstring strengthening to protect the ACL.
• Quadriceps-to-hamstring strength ratio: 0.6; 0.55 is also accepted (exam sheet).
• To help prevent ACL injury: hamstring strengthening (exam sheet, same point).

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Risk factors

Slides 33–46 group the risk factors into four headings: environmental, anatomical, hormonal and biomechanical.

Environmental

• Harder ground (resulting from high evaporation and low rainfall) may increase the shoe traction interfaceShoe traction interfaceHow much grip the shoe has on the playing surface.General meaning, not from the slides.
• Increasing the shoe-surface coefficientShoe-surface coefficientA number describing the friction (grip) between the shoe and the surface.General meaning, not from the slides may increase the risk of injury (direct risk) and alter movement (indirect risk).
• The role of prophylacticProphylacticUsed to prevent injury or disease.General meaning, not from the slides knee braces is confusing, except in one prospective randomized study of collegiate intramural football, which showed a 3× knee injury rate in participants not wearing a brace.

Anatomical (and the female athlete)

• It has been estimated that females are 4 to 8 times more likely to tear their ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides than males.
• Theories being investigated: forces with knee valgusValgusAngulation where the lower part of the limb points away from the midline. At the knee it is the inward collapse (knock-knee direction).General meaning, not from the slides or inward collapse of the knee on landing; less absorptive landing patterns such as straight-knee landing; muscular weakness; excessive quadricepsQuadricepsThe large muscle group on the front of the thigh that straightens the knee.General meaning, not from the slides activation in an eccentricEccentricA muscle contraction in which the muscle lengthens while producing force.General meaning, not from the slides activity.
• Exam sheet — estimated causes in females: knee valgus, decreased knee flexionFlexionBending a joint.General meaning, not from the slides angle, less landing absorption, straight-knee landing, muscle weakness and excessive quadriceps activation.
• Anatomical factors named on the slides:
  • The wider pelvis in females.
  • Increased quadriceps angleQuadriceps angleThe angle between the pull of the quadriceps and the patellar tendon. A larger angle goes with knee valgus.General meaning, not from the slides (Q-angle) (knee valgus).
  • Increased foot pronationPronationRolling of the foot inward so the arch flattens.General meaning, not from the slides.
  • Body mass index: its role is not clear, but higher indices seem to be associated.
  • Femoral notchFemoral notchThe groove between the two femoral condyles that the ACL passes through.General meaning, not from the slides indices, ACL geometry (smaller ACL) and tibial measurements are not definitively associated with increased risk of ACL tear. However, the smaller femoral notch in females, even when normalized to body weight, seems to be more associated.
  • Increased femoral anteversionAnteversionA forward twist of the upper end of the thigh bone relative to its lower end.General meaning, not from the slides.
  • Decreased muscular support, specifically the hamstringsHamstringsThe muscle group on the back of the thigh that bends the knee.General meaning, not from the slides, as possible causes of the higher ACL injury rate in women.
• Exam sheet — anatomical risk factors in females: wider pelvis, increased Q-angle, foot pronation and dominant quadriceps.

Hormonal

• Females are more susceptible to tearing their ACLs just before or after their monthly menstrual periodMenstrual periodThe monthly bleeding phase of the menstrual cycle.General meaning, not from the slides. Exam sheet: the hormonal risk factor is increased susceptibility to ACL injury around the menstrual period.
• Females experience a rapid surge of estrogenEstrogenA female sex hormone.General meaning, not from the slides just prior to ovulationOvulationRelease of an egg from the ovary during the menstrual cycle.General meaning, not from the slides, usually between days 10 and 14 of the cycle. Exam sheet: ovulation usually occurs between days 10 and 14.

The slide ties “days 10 and 14” to the estrogen surge just before ovulation; the exam sheet words it as when ovulation occurs. Both wordings are kept.

Biomechanical

• The ACL has different mechanical properties in women, which makes them more susceptible to injury.
• NeuromuscularNeuromuscularRelating to the nerves and muscles working together to control movement.General meaning, not from the slides factors appear to be the most critical difference between adult men and women and are modifiable.
• When landing from a jump or changing direction, women show:
  • less knee and hip flexion
  • increased knee valgus
  • increased internal rotationInternal rotationTurning a limb inward, toward the midline.General meaning, not from the slides of the hip
  • increased external rotationExternal rotationTurning a limb outward, away from the midline.General meaning, not from the slides of the tibia
• Slide 46 shows the Figure 11-36 diagram (see Function and biomechanics).

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Diagnosis and imaging

Clinical diagnosis

• The slide titled “Clinically” has no text on it.
• Doughy sensationDoughy sensationA soft, dough-like feel of the knee.General meaning, not from the slides: associated with ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides injury with effusionEffusionExcess fluid inside the joint, seen as a swollen knee. The protocol grades it as zero, trace, 1+, 2+ and higher.General meaning, not from the slides (exam sheet).
• Lachman testLachman testA hands-on test for ACL looseness: with the knee slightly bent, the examiner pulls the shin bone forward on the thigh bone.General meaning, not from the slides: performed at 20–30° of knee flexionFlexionBending a joint.General meaning, not from the slides, because the knee is unlocked and both ACL bundles can be assessed (exam sheet).

Objective 4 (stress testsStress testA test that applies a controlled force to a joint to see how much the ligaments let it move.General meaning, not from the slides for the cruciate injuries) has no slide of its own. The only stress-test content on the slides is the Lachman test and anterior drawerAnterior drawerA test for ACL looseness: with the knee bent, the examiner pulls the shin bone forward.General meaning, not from the slides in the strainStrainHow much a tissue stretches, given as a percentage of its resting length.General meaning, not from the slides chart (slide 23).

Radiological investigations

Plain X-ray; 3D CTCTComputed tomography: an X-ray scan that builds detailed cross-section or 3D pictures.General meaning, not from the slides; MRIMRIMagnetic resonance imaging: a scan that uses magnets and radio waves to show soft tissues such as ligaments.General meaning, not from the slides; examination under anaesthesiaExamination under anesthesiaExamining a joint while the patient is anaesthetised.General meaning, not from the slides and arthroscopyArthroscopyLooking inside, or operating on, a joint through small cuts using a camera.General meaning, not from the slides.

MRI of the ACL

• Slide 51 shows an MRI labelled “Normal Anterior Cruciate Ligament”, with an arrow on the ligament.

Primary signs of an acute ACL tear (slides 52–53):

• Abrupt angulationAbrupt angulationA sudden sharp bend in the course of the ligament on MRI.General meaning, not from the slides of the ACL.
• Rupture of the substance of the ACL, noticed by abnormal increased signal intensity (blue arrow).

Secondary signs of an acute ACL tear (slides 54–55):

• Anterior translocation of the tibiaAnterior tibial translationThe shin bone (tibia) sliding forward relative to the thigh bone (femur).General meaning, not from the slides (10 mm in the example).
• Femoral and tibial bone bruisesBone bruiseBleeding and swelling inside a bone without a visible break, often seen on MRI.General meaning, not from the slides (yellow arrows).

Exam sheet (MRI signs):

• Primary MRI sign of ACL rupture: anterior translation of the tibia.
• Secondary MRI signs: bone bruises and bone marrow edemaBone marrow edemaExtra fluid in the spongy inner part of a bone, seen on MRI.General meaning, not from the slides.
• A lateral femoral condyleFemoral condyleOne of the two rounded bumps at the lower end of the thigh bone (femur) that sit on top of the shin bone.General meaning, not from the slides bone bruise indicates ACL injury.

Conflict: the slides (54) list anterior translocation of the tibia as a secondary sign; the exam sheet calls it the primary sign. Both are kept. In the question bank the sheet’s answer is keyed and the explanation gives the slide’s version.

Segond fracture

• A Segond fractureSegond fractureA small flake of bone pulled off the outer edge of the top of the shin bone, associated with an ACL tear.General meaning, not from the slides is difficult to identify on radiographs (yellow arrows, a) but better clarified on MRI: T2PD-weighted and T2-weighted MRITwo types of MRI image setting. Each makes different tissues look brighter or darker.General meaning, not from the slides sagittalSagittalA view or plane that divides the body into left and right parts, so the knee is seen from the side.General meaning, not from the slides view (b) and axialAxialA cross-section view, as if slicing across the body.General meaning, not from the slides view (c).
• A 2017 MRI study of 36 Segond fractures associated with ACL injury showed the fracture fragment is almost always attached to the posterior fibers of the ITBIliotibial band (ITB)A thick band of tissue running down the outer thigh to the outer shin.General meaning, not from the slides and the lateral capsuleLateral capsuleThe fibrous sleeve that surrounds the outer part of the knee joint.General meaning, not from the slides; the authors were unable to demonstrate attachment to the ALL.
• Exam sheet: a Segond fracture is an avulsion fractureAvulsion fractureA fracture where a ligament or tendon pulls a small piece of bone away from the main bone.General meaning, not from the slides of the lateral tibial plateauTibial plateauThe flat top surface of the shin bone that forms the lower half of the knee joint.General meaning, not from the slides (the structure involved is the lateral tibial plateau).

Types of ACL tear

Slide 62 lists three types: intra-substance tear, partial thickness tearThickness (partial and full)Partial: only some of the ligament fibres are torn. Full: the fibres are torn all the way through.General meaning, not from the slides and full thickness tear.

Slides 59–61 are MRI images with no caption (slide 59 is labelled PCLPCLPosterior cruciate ligament: the knee ligament that crosses the ACL inside the joint and stops the shin bone sliding backward.General meaning, not from the slides; slide 61 is labelled F, ACL, PCL and T). Slide 63 shows PDWI and T2WI images and slide 64 repeats the “Normal vs acute tear” picture of slide 58.

MRI examples (slides 65–77)

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Treatment options and grafts

Choosing the treatment

• Treatment options for ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides injuries depend on age of the patient, activity level and intensity, and degree of instabilityInstabilityA sign or feeling that the joint moves abnormally or gives way.General meaning, not from the slides. Exam sheet: the factors determining the treatment choice are age, activity and degree of instability.
• Treatment choices:
  1. Give up or modify sport activities
  2. Brace and arthroscopicArthroscopyLooking inside, or operating on, a joint through small cuts using a camera.General meaning, not from the slides meniscectomyMeniscectomySurgery to remove part or all of a torn meniscus.General meaning, not from the slides
  3. Anterior cruciate ligament reconstruction

When to operate (ACL reconstruction)

• Reduction of swelling.
• Full range of motionROMRange of motion: how far a joint can move.General meaning, not from the slides is a must.
• Powerful muscle strength.
• Exam sheet: criteria before ACL reconstruction: no or minimal edemaEdemaSwelling caused by extra fluid in the tissues.General meaning, not from the slides, full range of motion, and good quadricepsQuadricepsThe large muscle group on the front of the thigh that straightens the knee.General meaning, not from the slides strength compared with the other side.
• Exam sheet: recommended prePREProgressive resistive exercise: strengthening with gradually increasing resistance.General meaning, not from the slides-operative rehabilitation for a complete ACL tear is at least 6 weeks; some papers recommend 8 weeks.

COPPERS criteria (Eastlack et al)

The slide spells the term COPPERSCOPPERSThe slide’s name for a set of four criteria (Eastlack et al): an isolated ACL tear, pain-free full ROM with no effusion, at least 70% MVIC, and pain-free single-leg hopping.. Eastlack et al developed these criteria:

1. An isolated tear of the ACL (no repairable meniscalMeniscusThe C-shaped cartilage cushion between the thigh bone and the shin bone.General meaning, not from the slides injury and no other concomitantConcomitantHappening or done at the same time as something else.General meaning, not from the slides ligamentous damage).
2. Full pain-free knee ROM, and no knee joint effusionEffusionExcess fluid inside the joint, seen as a swollen knee. The protocol grades it as zero, trace, 1+, 2+ and higher.General meaning, not from the slides.
3. At least 70% of the MVICMVICMaximum voluntary isometric contraction: the hardest a muscle can contract without the joint moving. value of the uninvolvedUninvolved limbUninvolved: the healthy, uninjured leg used as the comparison. Involved: the injured or operated leg.General meaning, not from the slides knee.
4. Once this milestone is achieved, the patient must be able to tolerate single-leg hoppingHop testingJumping on one leg and comparing the result with the other leg to check function.General meaning, not from the slides on the involved leg without pain.

Physiotherapy for a partial ACL tear (exam sheet)

• The first exercise for a partial ACL tear is the mini-squatMini-squatA shallow squat that bends the knees only a little.General meaning, not from the slides.
• Deep squat should be avoided initially; mini-squat is preferred.
• Closed kinetic chainCKCClosed kinetic chain: exercise with the foot fixed on the floor or a surface, such as a squat.General meaning, not from the slides exercise is preferred initially.

Graft choice (slides 83–90)

• SemitendinosusSemitendinosusOne of the hamstring muscles at the back of the thigh. Its tendon can be used as an ACL graft.General meaning, not from the slides or patellarPatellaThe kneecap.General meaning, not from the slides graftGraftTissue used to replace the torn ligament.General meaning, not from the slides.
• The most common graft used in the sports clinic is the hamstringHamstringsThe muscle group on the back of the thigh that bends the knee.General meaning, not from the slides graft.
• The patellar tendonPatellar tendonThe tendon that joins the kneecap (patella) to the shin bone.General meaning, not from the slides graft is used for the athlete who wants to return to sports quickly, for example at three months. The earlier return to activities is based on the faster bone-to-bone healingBone-to-bone healingHealing of a graft’s bone block into the surrounding bone.General meaning, not from the slides of the patellar tendon graft compared with the tendon-to-bone healingTendon-to-bone healingHealing of a tendon graft directly into bone.General meaning, not from the slides of the hamstring graft. The hamstring graft may take as long as three months to heal.
• Timed hop test score of 80% of the uninjured limb [male: 1.7 seconds, female: 2.25 seconds] (slide 84; the slide gives no context for the test).

The “three months” on slide 83 is about graft healing and earlier return to activities. The return-to-sport timeline on slides 95 and 139 is 9–12 months / at least 9 months (see rehabilitation). Both are kept.

• Exam sheet: the muscle commonly harvested for the graft is the semitendinosus. Two strips are harvested and prepared as a double-strand graftDouble-strand graftA graft made from two strands.General meaning, not from the slides.
• Exam sheet: the two graft fixation methods are interference screwInterference screwA small screw pushed into the bone tunnel beside the graft to hold it in place.General meaning, not from the slides fixation and suspensory fixationSuspensory fixationHolding the graft with a button or loop fixed on the outside of the bone, so the graft hangs from it.General meaning, not from the slides.

Surgical indications (slide 91)

• A young competitive pivotal athlete who wants to return to sports.
• Failure of a non-operative program, with persistent pain, swelling and giving wayGiving wayA sudden feeling that the knee is about to buckle.General meaning, not from the slides.
• A desire to increase the level of athletic activity without the use of a brace.
• A repairable meniscal tear in a young athlete.
• Meniscus repair has a high failure rate unless the knee is stabilized with an ACL reconstruction.

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Rehabilitation overview and pre-operative phase

Protocol at a glance

Slide 124’s title says “Immediate-post-operative (week 4-6)”, but the table on that slide is headed “Intermediate Post-Operative Phase (week 4-6)”. The notes use Intermediate.

Pre-operative rehabilitation (slides 93–95)

Phase goals: begin as soon as possible after the initial injury and re-establish the following before surgery:

• Full active (AROMAROMActive range of motion: movement the patient produces with their own muscles.General meaning, not from the slides) and passive (PROMPROMPassive range of motion: movement produced by someone else or a machine.General meaning, not from the slides) knee extension.
• Knee flexion ROM within 10° of the uninvolved limb.
• Trace to zero knee effusion.
• No knee extension lag with straight leg raise (SLR).
• Quadriceps Strength IndexQIQuadriceps Strength Index: quadriceps strength of the involved limb compared with the uninvolved limb. (QI) ≥ 80% of the uninvolved limb.
• Retain these values for post-operative comparison to minimize overestimation of strength.

Patient education:

• Importance of prehabPrehabRehabilitation done before surgery to prepare the knee.General meaning, not from the slides for optimal post-operative outcomes.
• What to do immediately after surgery (0–48 hours).
• Anticipated return-to-sport timeline: 9–12 months; allografts 12+ months.
• Expected outcomes.
• Return to the prior level of competition is often difficult, but possible.
• Osteoarthritis risk.

Exam sheet:

• Pre-operative rehabilitation for a complete tear: at least 6 weeks; some papers recommend 8 weeks.
• The criterion-based time for return to sport after reconstruction is approximately 9 months or more, based on maturation and return-to-sport criteria.

Abbreviations used in the protocol (slide 141)

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Early post-operative rehabilitation (weeks 1–6)

Immediate post-operative (week 1)

Slide 96 repeats only the goals and milestones part of this table (slide 97 has the full table). Further week-1 points from slide 120:

• Avoid unnecessary weight bearing throughout the day to minimize effusion and pain. Elevate the knee above heart level and ice as often as possible.
• Criteria to discontinue the brace / knee immobilizerKnee immobilizerA brace that keeps the knee straight and still.General meaning, not from the slides (if used): SLR without lagExtension lagBeing unable to straighten the knee fully by your own muscle power, although it can be straightened by hand.General meaning, not from the slides, no increased pain or effusion with weight bearing, and visible quad activation while ambulating in clinic. Crutches should be used as needed to normalize the gait pattern and help reduce knee effusion.
• Quadriceps MVIC strength testing: isometric testing performed once the patient can assume the test position (45–90° knee flexion) without pain. Use it to dose NMES for quad strengthening at each visit.
• Home exercise program (HEP): quad sets 5–10 sets of 100 × 5–10” per day; SLR (assisted as needed) 3 × 10; LAQ (90–0°) 30 × 5”; heel slides / seated assisted knee flexion / wall slides 30 × 5”; heel prop with ice 5 × 10 minutes per day; self-mobilization of the patella 20 × 5” each direction.

Exercises shown in the week-1 slides (99–119):

Passive knee extension and weight shifting (slides 99–101)

• Prone hangsProne hangLying face down with the lower legs hanging off the bed so the knee straightens passively.General meaning, not from the slides or heel propped in supine for passive knee extension.
• Weight shifting in standing for weight-bearing tolerance (anteroposterior and side to side).

CPMCPMContinuous passive motion: a machine that bends and straightens the knee for the patient.General meaning, not from the slides, gait training and cryotherapyCryotherapyTreatment with cold, such as ice.General meaning, not from the slides (slides 102–103)

• Continuous passive motion (CPM): 6 hours/day, increasing 5–10 degrees/day.
• Gait training with crutches and brace, level ground and stairs.
• Cryotherapy to reduce … (the slide text is cut off at the bottom edge).

Full knee extension and stretching (slides 104–108)

• Full knee extension is achieved by the heel on a block (heel prop, slide 105; heel prop exercise, slide 106).
• HamstringHamstringsThe muscle group on the back of the thigh that bends the knee.General meaning, not from the slides stretching — very gentle in case of a semitendinosusSemitendinosusOne of the hamstring muscles at the back of the thigh. Its tendon can be used as an ACL graft.General meaning, not from the slides graftGraftTissue used to replace the torn ligament.General meaning, not from the slides (slide 107).
• GastrocnemiusGastrocnemiusThe main calf muscle.General meaning, not from the slides stretches are done with a towel around the foot (slide 108).

Flexion up to 90° (slides 109–113)

• Increase flexion up to 90° is achieved by: passive flexion at the edge of the bed (slide 110), wall slides (slides 111–112) and heel slides (slide 113).

Quadriceps control (slides 114–119)

• Quadriceps (muscle/leg) control is achieved by: the quadriceps set exercise (slide 115), with electrical muscle stimulation performed at the same time (slide 116); then 2. SLR exercises (slide 117) and 3. Short-arc quadricepsShort-arc quadricepsA quadriceps exercise straightening the knee over a short range near full extension.General meaning, not from the slides muscle exercise, marked with a red (X) (slide 118).

The red (X) on slide 118 is on the slide; the slide does not give a reason in words. The next slide (119) is the Figure 11-36 diagram: close to full extension a forceful quadriceps contraction can induce anterior tibial translationAnterior tibial translationThe shin bone (tibia) sliding forward relative to the thigh bone (femur).General meaning, not from the slides, and past 60° of flexion there is little to no translation.

Early post-operative (weeks 2–3)

Monitoring and home programme (slide 123):

• Criteria to discontinue crutches: normal gait pattern with good active quad control, no lag with SLR and effusion ≤ 2+.
• Effusion monitoring: assess the response to exercises frequently; stay at the same intensity or decrease if effusion increases; do not progress exercise with a 2+ effusion. Refer to the Soreness Rules (appendix 2).
• Pain monitoring: modify exercise ROM and load to minimize irritation of the quad and patellar tendonPatellar tendonThe tendon that joins the kneecap (patella) to the shin bone.General meaning, not from the slides graft site (keep pain < 5/10).
• HEP: quad sets 5–10 sets of 100 × 5–10” per day; SLR (assisted as needed) 3 × 10; LAQ (90–0°) with resistance 30 × 5”; heel slides / seated assisted knee flexion / wall slides 30 × 5”; heel prop with ice 5 × 10 minutes per day; self-mobilizations of the patella 20 × 5” each direction; frequent short bouts of ambulation (3–5 minutes/hour).

Slide 121 gives the milestone “effusion < 2+”, while slide 123 gives the crutch criterion “effusion ≤ 2+”. Both are kept as written.

Intermediate post-operative (weeks 4–6)

• Effusion and pain monitoring: continue as outlined above.
• Preferred methods for assessing quad strength: isokinetic dynamometerDynamometerA device that measures muscle force.General meaning, not from the slides (for example Biodex) in isometric or isokinetic (60/90/120 degrees/sec) mode, handheld dynamometry with fixation, or 1 repetition maximum on a knee extension machine, 90–45° or 90°–0° (week 7+).
• Quadriceps Strength IndexQIQuadriceps Strength Index: quadriceps strength of the involved limb compared with the uninvolved limb. (QI): monitor for bilateral strength loss after injury. QI should be calculated using prePREProgressive resistive exercise: strengthening with gradually increasing resistance.General meaning, not from the slides-injury data for the uninvolved limb (if available) or the highest value collected during rehab, to avoid overestimating quadriceps strength in the involved limb.
• HEP (slide 126): SLR with resistance 3 × 10; LAQ with resistance 30 × 5”; prone quad stretch 3 × 30”; SLS 10 × 15”; squats (0–90°) 3 × 10; heel raises 3 × 10; self-patellar mobs PRN 20 × 5”; aerobic conditioning 10–15 minutes; step ups 3 × 10; single-leg squat eccentricsEccentricA muscle contraction in which the muscle lengthens while producing force.General meaning, not from the slides 3 × 10; planks 5 × 30”; hip strengthening 3 × 10.

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Later rehabilitation and return to sport (week 7 to month 12)

Late post-operative (weeks 7–9)

Exercise constraints (slide 130):

HEP (slide 130): resisted squats (0–90°) 5 × 8; LAQLAQLong arc quadriceps: a knee-extension exercise through the long range from 90° to 0°. with heavy resistance 3 × 15; unilateral heel raises 3 × 10; aerobic conditioning 15–30 minutes; resisted step ups 3 × 10; SLSLSingle-leg.General meaning, not from the slides squats 3 × 10; planks 5 × 60”; resisted SL RDLsRomanian deadlift (RDL)Romanian deadlift: a hip-hinge lift performed with nearly straight knees. 3 × 12; hip strengthening 3 × 10.

Transitional phases I and II

Return to level ground running criteria (slides 132–133, the same slide twice): quadriceps strength ≥ 80%, effusion ≤ trace, understanding of soreness rules; appendix 1 for considerations specific to allograftsAllograftA graft taken from a donor.General meaning, not from the slides.

Transitional phase III (months 4–6)

Return to agilities criteria (for example forward and lateral cone shuttle, figure-8): progress from pre-planned to reactive, include sport-specific equipment as appropriate.

• Quadriceps strength ≥ 80%; effusion ≤ trace; hop testing ≥ 80% (appendix 7); understanding of soreness rules; completion of running and Stage 1 sprint progression; appendix 1 for allografts.

Return to high-intensity plyometrics criteria (for example box jump, drop jumps, broad jump): progress from two-feet landing to one-foot landing, single plane to multiplanar.

• Quadriceps strength ≥ 85%; effusion ≤ trace; hop testing ≥ 85% (appendix 7); completion of running progression; completion of Stage 1 sprint progression; no apprehensionApprehensionFear or hesitation that the knee will give way.General meaning, not from the slides with light agilities.

Home exercise programme (slides 135–136): individualized to the specific sport and patient needs; ensure the demand is enough to improve working capacity with sport-specific skills (example: soccer player, not fully inclusive).

Transitional phase IV (months 6–9)

Criteria listed on slide 138:

The criteria for Stage 1 sprint progression are not on the slides.

Return to sport, phase V (months 9–12)

Return to competition progression:

1. Non-contactNon-contact injuryAn injury that happens without a direct blow from another player or object.General meaning, not from the slides practice
2. Small-sided contact practices (1v1, 2v2, 3v3)
3. Full practice
4. Return to competition with restricted workload
5. Return to competition unrestricted

All stages without apprehension, pain, instabilityInstabilityA sign or feeling that the joint moves abnormally or gives way.General meaning, not from the slides, effusion or compensations.

ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides secondary prevention program:

• 2× per week moving forward.
• Maintain quadriceps strength and periodically assess it with a 1-RM knee extension strength test (pre/post season).
• See the Knee Injury Prevention CPGCPGClinical practice guidelines. for guidelines and video examples.
• Consider long-term implementation of Copenhagen planks and Nordic hamstring curls for lower extremity injury risk reduction.
• If a functional ACL brace is used, it may be discontinued after 1 year.

Additional considerations:

• No effusion, pain or apprehension with sport-specific training and practice progressions.
• Return to pre-injury conditioning level.
• Minimal to no dynamic knee valgusValgusAngulation where the lower part of the limb points away from the midline. At the knee it is the inward collapse (knock-knee direction).General meaning, not from the slides with jumping and landing.
• Hamstring/quadriceps ratio.
• Vertical hop symmetry assessment.

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Concomitant procedure modifications

Slides 142–145 list how the rehab changes when another procedure is done at the same time as the ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides reconstruction (procedure → rehab modification).

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High-yield exam review

The 41 questions and answers from the course sheet “ACLACLAnterior cruciate ligament: a strong band inside the knee that stops the shin bone (tibia) sliding forward under the thigh bone (femur).General meaning, not from the slides 1 – Important Exam Questions”, worded as on the sheet.