Common Paediatric & Adolescent Knee Problems Dr. Lyall J. Ashberg, MD Specialising in Paediatric and Adolescent Orthopaedics Offices at Netcare Blaauwberg & Sea Point Medical Centre Cape Town, South Africa Ph: 021 554 2055 Fax: 021 554 2065 Email: Ashbergortho@gmail.com
Growth and Development✤ Why do young children who fall so frequently not get injured more often? ✤ Young tissues are more pliable and energy absorbing✤ Stage of growth and development is essential when evaluating paediatric knee problems✤ Physis (growth plate) is weakest part of child skeleton✤ Most of growth of lower limb occurs at knee (2/3)
General Principles✤ Kids are not little adults✤ Adolescent knee problems are similar to adults unless they are still growing- Preadolescent✤ There is a spectrum of pathology significantly dependent on stage of development✤ One needs to distinguish what is physiologic vs pathologic✤ Males and females have different biomechanics which leads to different injury profiles (ACL epidemic in females)✤ Preseason training/Strength and conditioning programmes are safe and effective in preventing injuries and improving performance in kids
Epidemiology✤ M>F✤ Adolescent females are approaching males✤ In the US, there has been a 4 fold increase in female ACL (1:8) injuries ✤ Q angle, ligament laxity, genu valgum, ext tib torsion, fem Anteversion , inter condylar notch shape, ACL size, biomechanics, hormonal influences.✤ Highest incidence in adolescence 2 to sport
Overuse Problems: Apophsitis✤ Apophysis: specialized growth centre/cartilage attached to a tendon or muscle ✤ Much weaker than attached tendon. ✤ Thus the terms tendinitis often doesnt apply ✤ Examples: tibial tuberosity, olecranon apophysis, Calcaneal apophysis
Overuse Problems: Apophsitis Traction apophysitis is very common around the knee Osgood Schlatters: tibial tuberosity Sindig-Larsen-Johannsen: Inferior pole patellaOccurs around age 10-15, earlier in girls✤Often very active in sports✤ ✤ More common in boys+/- growth spurt✤Relative extensor mechanism inflexibility✤Associated with jumping squatting, cutting sports✤
Overuse Problems: Apophsitis✤ Usually self-limiting✤ Resolves after skeletal maturity✤ Improved with Extensor Mechanism stretches/physio✤ Modification of activities✤ Anti-inflammatories✤ Rarely surgery is necessary to remove ossicles after skeletal maturity ✤ Pain with kneeling
Acute Patella Instability/DislocationOften results from direct blow or valgus load✤Results from disruption of MPFL✤✤ Primary stabilizer of the patella✤ Most often avulses off femur✤In otherwise normal knee, frequentlyassociated with chondral injury
Acute Patella Instability/Dislocation✤ Pt usually describes hearing or feeling a "pop"✤ Immediate, large haemarthrosis✤ Knee collapsing and unable to bear weight✤ Tender over course of MPFL & LFC✤ Often have "Apprehension" with lateral glide test
Patella Dislocation-Treatment ✤ First Time Dislocator✤ Acute Care ✤ +/- evacuate haematoma for comfort ✤ Knee immobilizer ✤ Xrays/MRI looking for intrarticular loose body✤ Family given option of non-operative tx ✤ Up to 30% fail conservative tx.
Patella Dislocation-Treatment✤ Conservative Treatment ✤ Immobilization until quad inhibition resolves (2-4 wks) ✤ Physio for Quad (?VMO) strengthening/proprioception ✤ Return to sports no sooner than 3 months or until they have protective quad/hamstring strength.
Operative Treatment✤ Very complex decision making✤ Need to consider ✤ Limb alignment and rotation ✤ Valgus limbs/Excessive femoral anteversion ✤ Q angle ✤ Trochlear depth ✤ Ligamentous integrity ✤ Both generally and MPFL
Operative Treatment✤ Mainstay is MPFL repair or reconstruction ✤ Many different techniques✤ Roux-Goldwaith procedure in skeletally immature or medialization of tibial tubercle in skeletally mature✤ Insall proximal realignment✤ Trochlear deepening procedure✤ Femoral/Tibial derotation
Meniscus Problems✤ Other than articular cartilage, the meniscus is probably the most important structure in the knee✤ C-Shaped, biconcave wedge shaped structures made of fibrocartilage in lateral and medial joint compartments✤ Functions: ✤ Load sharing and shock absorption ✤ Protects articular cartilage✤ Complete meniscectomy results in up to 350% increase in contact pressures!✤ Secondary Stabiliser✤ Proprioception✤ Synergistic role in joint lubrication
Meniscus Problems✤ Vascularity and Healing✤ In the neonate, meniscus is extensively vascularised✤ Persists until age 2 at which point begins to recede✤ Only 10-30% of meniscus has blood supply✤ Red-red✤ Red-white✤ White-white
Epidemiology✤ Traumatic injuries in children younger than 10 are rare✤ Congenital malformations (Discoid Meniscus) may predispose to injury✤ As children approach adolescence, potential for injury increases✤ Increase in organised sports has increased the number of serious intrarticular knee injuries
Meniscus Problems✤ History✤ Often sustain either twisting injury or varus/valgus load on fixed limb✤ +/- "pop"✤ Swelling/effusion (51%) ✤ Chronic tears may present with intermittent, activity related swelling✤ Clicking/Popping/locking (bucket handle tear)✤ Stiffness and pain
Meniscus Problems✤ Physical✤ Effusion✤ Decreased ROM✤ JOINT LINE TENDERNESS✤ VALGUS/VARUS ROTATION and STRESS TEST✤ SQUAT TEST✤ McMurrays/Apleys: only around 58% reliable
Meniscus Problems✤ Treatment✤ Indicated in acute tears and chronic tears with mechanical symptoms✤ In child or adolescent, make every effort to retain childs own parts✤ Partial excision✤ (Total Excision)✤ In ACL deficient/unstable knee, MUST address ACL at same time or repair will fail
Meniscus Problems RehabPost Menisectomy✤✤ WBAT✤ ROM✤ Quad-Hamstring rehabPost Repair✤✤ Non-weightbearing at least 6 weeks✤ ROM✤ Quad-Hamstring rehab✤ No competitive sports at least 3-6 months
Discoid Meniscus✤ Congenital variant present at birth✤ Three types✤ Most often assymtomatic✤ In the young child may present as dramatic snapping, either audible or palpable✤ May result in abnormal biomechanics of knee
Discoid Meniscus✤ Treatment✤ Assymptomatic children do not require treatment✤ Will occasionally tear in older child or adolescent✤ Symptoms of swelling and lateral joint line pain✤ Saucerization of meniscus and repair/stabilisation✤ Occasionally associated with OCD of LFC✤ Addressed as per OCDs
Osteochondritis Dissecans✤ "Bone-cartilage separation/dissection"✤ Occurs in Juvenile (5-15) and adult forms (16-50)✤ More common in males✤ After skeletal maturity prognosis is much worse✤ Most often affects lateral aspect of medial femoral condyle✤ Felt to result from repetitive microtrauma although other factors probably contribute✤ Separation of osteochondral fragment highly likely to result in DJD
OCD✤ Presentation✤ Depends on lesion stability✤ Stable lesions✤ Aching activity related pain✤ No effusion✤ Point tenderness over lesion✤ Unstable Lesions✤ More likely to have mechanical symptoms✤ Effusion✤ More painful
OCD ✤ Treatment ✤ Depends on age of patient and lesion characteristics✤ Nonoperative ✤ Usually involves initial period of immobilisation ✤ Rehab ✤ Gradual return to sports under close observation ✤ Repeat MRI
OCD✤ Factors associated with failure of non-op treatment✤ Larger sized lesion✤ Greater Skeletal maturity✤ High signal behind lesion on MRI
ACL Injuries✤ Embryologic development is intimately related to that of menisci✤ Congenital absence can occur but usually associated with other lower limb anomalies✤ It is an intrarticular-extrasynovial structure ✤ This has implications for healing✤ The relationships of its insertion site on the femur and tibia remain constant throughout growth✤ Origin on the femur is all epiphyseal and very close to the distal femoral growth plate
ACL Injuries ✤ Biomechanics✤ Primary restraint to anterior translation of the tibia and femur✤ Primary stabiliser during jump, cut and twist sports✤ Comprised of anteromedial and posterolateral bundles✤ In the growing knee it is the “middle component” of a complex viscoelastic chain
ACL Injuries ✤ Biomechanics✤ Failure mode depends on a myriad of loading and host characteristics ✤ Age of the child ✤ Sex ✤ Hormonal influences ✤ Structural factors
ACL Injuries ✤ Epidemiology and Risk factors✤ Increasing frequency secondary to participation in organised sports✤ Major risk factors include ✤ High knee-demand sports ✤ Female gender ✤ Immature neuromuscular development✤ Concurrent meniscal injury is common✤ ACL injury is a common cause of haemarthrosis
ACL Injuries ✤ Injury Patterns✤ Midsubstance tears more common after age 12✤ Bony avulsion most common at tibial spine and in kids <12✤ Partial tears are more common in pre-adolescent✤ Partial tears which are associated with instability are “functionally complete” and should be addressed as such
ACL Injuries ✤ Natural History✤ Developmental and behavioral issues may predispose children with ACL-deficient knee to become “non-copers”✤ Non operative treatment is associated with ✤ Recurrent instability ✤ Cumulative meniscal and cartilage damage ✤ Sports related disability
ACL Injury✤ History usually reveals a non-contact, rapid deceleration mechanism often with a valgus load and rotation of the tibia on femur✤ Often feel a “pop” and rapid knee swelling and pain✤ Children’s symptoms tend to resolve quickly and often return to activities✤ Need to distinguish between patellofemoral and ACL type instability✤ Lachman maneuver is easiest and most sensitive exam✤ Routine xrays for bony avulsions✤ MRI to document concurrent injuries to menisci and cartilage
QuickTime™ and a decompressor are needed to see this picture.ACL rupture in female basketball player
Lachman Anterior Drawer QuickTime™ and a decompressor are needed to see this picture. Pivot Shift Test
ACL Injury ✤ Treatment Considerations✤ Distal femoral and proximal tibial growth plates are responsible for majority of lower extremity growth✤ Although rare, angular deformities have been described following reconstruction ✤ Mostly secondary to inappropriately placed fixation or bone placed across the physis✤ Is is better to cause a growth disturbance or allow for arthritis?
ACL Injury ✤ Treatment Considerations✤ When approaching treatment in a child I consider ✤ Tanner stage/sexual maturity ✤ Bone age ✤ Activity level and type of sport ✤ Symptomatology during ADLs ✤ Family desires
ACL Injury✤ Treatment Considerations✤ Nonoperative: ✤ Decrease pain and swelling ✤ Regain quad function and normal gait ✤ Comprehensive lower extremity strengthening and proprioception ✤ Knee brace ✤ Avoidance of cutting sports ✤ Recurrent instability is not an option!
ACL Injury ✤ Treatment Options✤ Direct Repair ✤ Not typically an option as this has a very high failure rate✤ Extrarticular procedures ✤ Avoids physis ✤ Fixation is outside the knee
ACL Injury✤ Physeal Sparing procedures ✤ Fixation either in epiphysis or across one physis✤ Transphyseal all soft tissue with extraphyseal fixation✤ Adult type reconstruction ✤ Bone-patella tendon-Bone ✤ Hamstrings ✤ Allograft ✤ Quad Tendon
Other Ligaments✤ “Children are not small adults”✤ Again, in pre-adolescent child need to consider the growth plate as the “weakest link” ✤ Ligaments are more likely to fail at lower rate of load ✤ Physis fails at higher rate of load✤ Beware the PCL/PLC injury in ACL deficient knee ✤ Posterolateral rotatory instability✤ Children’s knees in these injuries tend to be more “forgiving and usually amenable to non-operative management
Fractures✤ Becoming more common and more severe in children ✤ Greater level of sports participation ✤ High energy sports ✤ motorized sports ✤ High level contact sports ✤ MVAs and unbuckled children in SA!!
Fractures✤ Fracture related growth problems are seen most frequently after injuries about the knee✤ Can have life and limb threatening consequences✤ Need to have a high index of suspicion in growing child ✤ Not a sprain/strain unless proven otherwise✤ Should almost always get at least an xray in knee injured child✤ Have a low threshold for advanced imaging✤ Don’t normally recommend “stress views”
Fractures✤ Distal Femoral and Proximal Tibial Physeal fractures✤ Most common fractures mistaken for ligament injury ✤ Need a high index of suspicion ✤ Treat as such until proven otherwise✤ Can be most devastating to growth and life/limb✤ Non-displaced fractures can usually be treated in a cast✤ Displaced or intrarticular fractures frequently require surgery
Fractures Tibial Eminence fractures ✤ ACL equivalent in pre-adolescent child ✤ Most common in children 8-14 years old ✤ 3 types-Meyers and Mckeever ✤ Type I-II usually amenable to cast immobilisation ✤ Type III always operative ✤ Not uncommon to have residual, post fixation laxity on objective testing ✤ Indicates ACL “stretch” ✤ Usually not clinically significant
Fractures ✤ Tibial Tubercle and Patella Sleeve Fractures✤ Mostly sports related✤ Typically occur between 12-17 y/o✤ Usually secondary to violent contraction of quad ✤ eg. Landing a jump✤ At tubercle, fracture occurs at junction of ossified and cartilage growth plate✤ Sleeve fractures occur because of cartilagenous attachment at inferior pole of the patella ✤ Difficult to diagnose, but can result in complete disruption of extensor mechanism.
Infections✤ Relatively common in younger children✤ Can occur from direct injury, haematogenous spread or concurrent osteomyelitis ✤ Growth plates are intrarticular✤ Distinguished from ✤ Toxic Synovitis - self limiting ✤ Septic Prepatellar Bursitis - Extrarticular infection ✤ JIA
Infection✤ Septic Arthritis ✤ Often ill looking child ✤ Will not bear weight ✤ Definitely won’t let you move their knee ✤ + Effusion ✤ Warm and sometimes red ✤ Intrarticular bacterial infection is a surgical emergency!
Take Home Points✤ Children are not little adults✤ Need to consider the growth plate and child’s stage of development ✤ “The weakest link”✤ Effusions tend to mean unhappiness is brewing✤ Beware the occult fracture✤ Don’t forget about the hip and referred pain
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