Definition
Localised injury or condition affecting an articular surface that involves separation of cartilage & subchondral bone
Epidemiology
Two distinct populations of patients involved
Juvenile form
Children & adolescents between 5-15 years with open physes
Adult form
Older adolescents & adults
Rare in patients younger than 10 & older than 50
Most frequently in young male athletes
Can be multifocal & familial
Areas affected
Lateral surface medial femoral condyle knee
Posteromedial corner talus in the ankle
Superomedial part femoral head
Humeral capitellum
1st metatarsal head
Knee most commonly affected joint – 75%
Aetiology
Trauma (repeated minor trauma)
Ischaemia
Defect of ossification
Genetic
Trauma
Indirect trauma most likely as the posterolateral area of the MFC most involved
Repeated minor trauma
Fairbank proposed impingement of the tibial spine on lateral part of the MFC during internal rotation of the knee
Aichroth proposed that odd facet of patella articulates with lateral part of the MFC during flexion & causes lesion with patellofemoral contact
The osteochondral fractures of the LFC after patellar dislocation is not OCD
Ischaemia
Abnormal subchondral bone structure predisposes to pathological fracture
Enneking suggested that subchondral bone has vascular end-arterial arcade (mesentery like) & so ischaemic segment of bone could occur & act as sequestrum
Granulation tissue thus forms between the viable & necrotic bone
The lesion of osteonecrosis should be distinguished
Histological studies of loose bone showed no AVN
Defects of Ossification
Abnormality of ossification that fails to heal
Stress to the affected segment leads to partial or complete detachment
Some investigators suggested that irregularity or roughening of the distal femoral epiphysis may be normal
Genetic Causes
Families identified with predisposition of OCD in multiple joints
Associations with OCD and
Dwarfism
Tibia vara
Perthes disease
General Treatment Principles
Nonoperative
Load reduction
Restrict activity
Complete healing in children may take 2 years
Consider operative intervention if
Loose bodies present
Symptoms > 6-12 months
Healing unlikely from radiographic indices
If operate then options are
Debride & drill to promote healing }
Reattach fragment } protected WB & early ROM
Mosaicoplasty }
Salvage procedure (eg HTO)
Knee
Clinical
Early poorly-defined symptoms
Pain
Swelling
Progression associated with
Catching
Locking
Giving way
Intermittent & related to activity or exertion
Age of patient at time of presentation is primary determinant of treatment
Examination
Lateral aspect of medial femoral condyle most commonly affected
Medial femoral condyle tenderness & crepitus
Joint effusion
Wilson Test positive
Flex to 90°
Internal tibial rotation
Slow extension giving pain
Seen at 30° of extension
Relieved by external rotation of tibia
Imaging Studies
MFC affected in 75-85% of cases
1/4 on the weight bearing area
Notch A-P XR best way to visualise this lesion
Lateral XR has two lines described by Harding
– One along the posterior femoral cortex &
– One along Blumensaat line
– Segment A is above Blumensaats line
– Segment B is in area between lines
– Segment C is in area below the posterior femoral cortex line
Arc between these two lines is common site for lesions
Cahill & Berg – Classified A-P radiograph into 5 segments
– Medial Tibiofemoral area is segments 1 & 2
– Notch area is 3
– Lateral Tibiofemoral area is segment 4 & 5
The same authors described the lesions from bone scan performed 6 weekly
Four stages of lesions
– Stage 1 – Visible on plain XR but normal bone scan
– Stage 2 – Visible on plain XR & ↑ uptake on scan
– Stage 3 – Above with ↑ uptake in whole of MFC
– Stage 4 – All of above & ↑ uptake in area of adjacent tibial
condyle
They used this as guide for treatment with stage 2 & above thought to heal due to osteoblastic activity
MRI
More sensitive than plain XR & correlates closely with arthroscopic findings (XR does not)
Determination of
Displacement of fragment
Fluid interfaces
Integrity of the articular surface
Improved with Gadolinium contrast
Arthroscopic Classification
Described by Guhl & used to plan operative management
– Intact lesions – cartilage intact
– Lesions showing early separation
– Partially detached lesions
– Craters with loose bodies
salvageable
unsalvageable
Natural History & Treatment
Dependent on age of patient at presentation
Juvenile lesions frequently heal
Once separation of fragment of bone from the base occurs healing unlikely
Healing of articular cartilage occurs through fibrocartilaginous metaplasia
Less resilient & degeneration more rapid
Principles of Operative Treatment
Restoration of articular congruity
Enhancement of local blood supply to fragment or crater
Rigid fixation of unstable fragments
Protected weight-bearing with motion ASAP
Accepted Indications
Symptomatic loose bodies
Detachment during observation
Predicted physeal closure within 6-12 months
Juvenile lesions that remain symptomatic despite non op treatment
Established non union of fragment
Surgical options
Excision of fragment & drilling the base
– Poor results when large & in weight bearing area
– But may be better to excise than reattach poorly fitting fragment
Reattachment of fragment
– Bone graft may be used & fixation varies from K-wires to Herbert Screws
– Articular congruity of paramount importance
Osteochondral allo/ auto grafts
– Good early results with the autografts obtained from around the knee – Mosaicoplasty
Summary of Treatment Plan
Children with symptomatic lesion managed non op with limitation of activity & protected weight-bearing
Operative intervention if
– Loose bodies present
– Symptoms > 6-12 months
– Healing unlikely from radiographic indices
Preserve the fragment if possible
In adults
– Lesions with intact articular cartilage drilled in retrograde fashion
– Separated lesions treated with curettage & drilling of base of lesion & replacement of lesion
– May need bone grafting to produce congruity of articular surface
– Excise only if small fragment or not reconstructable
– Consider mosaicoplasty
– Protected weight-bearing with early motion essential
In much older adult may consider TKR or HTO with advanced secondary Osteoarthritis
Ankle
Clinical Presentation
Catching with walking or active ROM
First seen in early adulthood usually
Often history of trauma
Swelling frequent & initial symptoms attributed often to sprain
Lesions classically
– Anterolateral
– Posteromedial
Posteromedial often asymptomatic with no history of trauma
Physical Examination
Crepitus or joint effusion
Well defined tenderness
Pain with compression of the tibiotalar joint common
Imaging Studies
Berndt & Harty classification system of osteochondral talar lesions
– Stage 1 – Small area of subchondral bone compression
– Stage 2 – Partially detached flap of cartilage
– Stage 3 – Completely detached fragment that lies in the bed (most
common)
– Stage 4 – Loose body
CT scan will help distinguish from cystic lesions or osteonecrosis
Help determine size & location of lesion
MRI will help distinguish between the Stage 2 & 3 lesions with the fluid interface
Aetiology
More clear relationship with trauma than in other sites
Impingement of talus on the tibia or fibula produces lesion
Cadaveric studies by Berndt & Harty showed
– Anterolateral lesions by talar impaction on fibula during inversion in dorsiflexion
– Posteromedial lesions by impaction against the posterior tibial plafond during inversion in plantarflexion
Canale had found that the lateral lesions more likely to be traumatic in nature
The lateral lesions are wafer shaped but medial lesions dome-shaped
Natural History & Treatment
Suggest that Stage 1 & 2 lesion be treated non op with protected weight-bearing
The Stage 3 & 4 should have debridement & drilling of base but the anterolateral lesions more likely to give symptoms & lead to greater degree of degenerative changes than the medial lesions
Arthroscopic debridement useful but often difficult to access the posteromedial lesion & so arthrotomy may be required
Elbow
Clinical Presentation
Pain, swelling & loss of motion
Adolescence to early adulthood
Uncommon but related to overuse particularly throwing
Little Leaguers Elbow – valgus compression overuse in immature elbow causing OCD of the capitellum
Pappas divided into 3 categories dependant on age of patient
– Category 1 – patients < 13 years of age
– Category 2 – 13 years to adulthood
– Category 3 – adults
Better prognosis seen in younger patients
Imaging Studies
X-ray often sufficient to make diagnosis
See area of rarefaction or radiolucency on lateral or central portion of the capitellum
Loose bodies in late stages
Radial head hypertrophy also in later stages
If entire capitellum involved in child 4-8 years of age then suspect Panner’s disease
MRI very sensitive as per previous text
Aetiology
Trauma
Proposed by many investigators
Valgus overload on the radiocapitellar joint
Fatigue failure of the subchondral area
Separation of the bone from its bed
Overlying cartilage fails under shear stress & separates
The cartilage remains alive with synovial nutrition but bone avascular
Ischaemia
Predominant blood supply to the capitellum from posteriorly located vessels
Thus tenuous blood supply & at risk here
Natural History & Treatment
Poorly understood
Treatment usually involves debridement of loose bodies
Drilling of base of lesion did not affect outcome
Loss of full extension of elbow common