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Wheeless' Textbook of Orthopaedics

Osteochondral Lesions of the Talus



Co-Authors:  Milford H. Marchant Jr., M.D.; Steven Anderson, M.D.; M.D.; Mark E. Easley, M.D.; James A. Nunley II., M.D.



History
       - Konig in 1888 described “Osteochondritis Dissecans” in the knee
               - Distinct lesion with detachment of articular cartilage from subchondral bone forming a loose body
       - Kappis in 1922 described similar process in talus
       - 1959 Berndt and Harty provided great insight into the pathoanatomy and pathophysiology

Talus - Anatomy Review
       - Receives forces 5 – 10 times the body weight during normal ambulation
       - 3/5 of surface is covered by articular cartilage
       - Articular Cartilage is 1 – 2 mm thick
       - No Muscular Attachments
       - Delicate Blood Supply
       
Etiology
       - Primary Cause = Trauma
               - Controversial
               - Berndt and Harty through cadaveric studies showed that the OLT was likely a result of trauma
               - Transchondral Fracture of Talar Dome
                       - Medial Lesions were created when the posteromedial talar dome impacted
                               the tibial articular surface during combined plantar-flexion, inversion and external rotation
                       - Lateral Lesions generated when the anterolateral talar dome impacted
                               the fibula during inversion and dorsiflexion
       - Other Causes
               - Ischemic Necrosis
               - Embolic phenomenon
               - Ossification Defects
       - Predisposing Factors
               - Endocrine Disorders
               - Peripheral vascular disease
               - Genetic Predisposition?
                       - 10-25% Bilateral Lesions

Prevalence
       - Average Age Ranges 20 – 35 years
       - Male 70% : Female 30%
       - 6% of pts with any hx of Ankle Sprains, have OLTs
       - 38% of pts w/ SER-IV ankle injuries, have OLTs
       - 16 – 23% of pts undergoing lateral ligament reconstruction, have OLTs


     
Evaluation
       - Presentation
               - Acute inversion injury
               - Chronic Ankle pain
                       +/- history of trauma
                       +/- instability
               - Known History of OLT +/- prior treatment
       - Symptoms
               - Pain
               - Catching, grinding
               - Feelings of instability and give-way episodes


       
Diagnosis and Staging
       - Radiography
               - X-ray – initial evaluation
               - MRI – modality of choice for suspected lesions
               - CT-Scan – modality of choice for known lesions
       

Figure 1

Figure 2

Figure 3


       - Arthroscopy
               - Gold standard for diagnosis and determining optimal treatment modality 
     

Figure 4




       - Staging
               - Radiographic (Berndt and Harty)
                       1. Trabecular compression fracture of subchondral bone
                       2. Partially detached osteochondral fragment
                       3. Completely detached, non-displaced fragment
                       4. Detached and displaced fragment 
                      - Transchondral fractures (osteochondritis dissecans) of the talus.
               - Arthroscopic Staging (Pritsch, et al. (1986))
                       1. Intact, firm, shiny cartilage
                       2. Intact, soft cartilage
                       3. Frayed Cartilage 
                      - Arthroscopic treatment of osteochondral lesions of the talus.

               - Radiographic and Arthroscopic findings did not always correlate.
                       - Many are now using Berndt & Harty Staging with arthroscopic evaluation
                       - Advanced Radiographic modalities are also helpful

               - CT Staging (Ferkel, et al. (1990))
                       Stage 1 – Cystic Lesion within the Talar dome
                       Stage 2a – Cystic lesion with communication to the Talar dome
                       Stage 2b – Open articular surface lesion with overlying non-displaced fragment
                       Stage 3 – Non-displaced lesion with lucency
                       Stage 4 – Displaced fragment 
                      - Arthroscopic treatment of osteochondral lesions of the talus: long-term results. Ferkel, et al. Orthop Trans. 1990;14:172-173
               - Magnetic Resonance Staging (Hepple, et al. (1999))
                       1. Articular Cartilage Damage only
                       2. Cartilage injury with underlying fracture
                               a. Surrounding bony edema
                               b. Without edema
                       3. Detached but non-displaced fragment
                       4. Detached and displaced fragment
                       5. Subchondral cyst 
                      - Osteochondral lesions of the talus: a revised classification.
        
               Mintz, et al.  (2003) 
                       - Compared MRI with Arthroscopic findings for the purpose of grading
                       - 92 patients with persistent ankle pain & swelling
                       - 100% specificity in identification and localization of lesions.
                       - Accurate Grading in 83% of cases
                               - 95% sensitive and 100% specific in Disease positive (grade 0 – 1) vs. Disease negative (grade 2 – 5) analysis 
                       - Osteochondral lesions of the talus: a new magnetic resonance grading system with arthroscopic correlation.

Classic Lesions
       - Anterolateral
               - Shallow
               - Traumatic
       - Posteromedial
               - Deep
       - Central lesions have also been described



Treatment Planning
       - Acute vs. Chronic symptoms along with Radiographic Staging / Severity of Lesion dictate treatment
               - Acute Injuries
                       - Initial management if no radiographic evidence of fx or OLT
                       - Activity Restrictions
                       - Ice
                       - Trial of Immobilization
                       - Compression
                       - Elevation
               - Chronic Injuries
                       - Essential to define the severity of the lesion
                       - Low-Grade:  Operative vs. Non-operative
                               - Condition of articular cartilage in question
                               - With MRI Grade I – II lesions most attempt a 4 – 6 month trial of conservative therapy +/- immobilization
                               - Immobilization for 4 – 8 weeks
                               - Persistent symptoms after conservative therapy = Arthroscopy
                       - High Grade:  Operative Management
                               - Lesion stability during arthroscopic evaluation
                               - With MRI Grade III – V injuries = arthroscopic intervention
                               - Depending on the location, size, and character of the lesion various reconstructions may be performed
       - Other Factors
               - Location of the Lesion
               - Quality of Subchondral Bone
               - Ankle Instability
               - Prior Interventions
       
Treatment Modalities
       - Non-Tissue Transplantation
               - Internal Fixation
               - Arthroscopy
                       - Excision
                       - Curettage / Abrasion
                       - Drilling
                       - Micro-fracture
                     
               Robinson et al (JBJS 2003)
                       - 65 patients
                       - Improvement seen with arthroscopic treatment in MRI grade I – IV.
                       - Grade V cystic lesions had high incidence of poor outcome (53%).

Figure 5


       - Tissue Transplantation
               - Modalities
                       - Autologous Bone Grafting
                       - Autologous Chondrocyte Transplantation
                       - Osteochondral Autograft Transplantation (OATs)
                               - Single Osteochondral Plug
                               - Mosaicplasty
                       - Osteochondral Allograft Transplantation
               - Benefits
                       - Provides the ability to fill in a larger defect



Osteochondral Autograft Transplantation
       - Benefits
               - Non-immunogenic graft
               - No increase in disease transmission
               - Provides an articulating surface
               - Prevents excessive weight bearing loads on the remaining portion of the talus which would accelerate ankle joint arthritis
       - Structural Limitations
               - Lesion size = Limited “extra” cartilage
               - Only Carticel can fill irregular shaped lesions
               - Flat surface required
               - Attempts at angular repairs have been challenging

Figure 6




Osteochondral Lesions of Talus - Allograft Transplantation:
       - Allograft Transplantation is proving to be beneficial for large osteochondral defects where duplication of the anatomy would be difficult with autologous tissue.

       - Talus allograft is size matched = Custom fit
               - Able to treat the “shoulder lesion” (See Figure)
                       - Defect involving more than one articulating plane
       - Benefits
               - In Fresh Allografts, Viable Chondrocytes are present within an intact Hyaline Cartilage Structure
                       - Arthroscopy and Mosaicplasty rely on fibrocartilage ingrowth
               - Shorter procedure
               - No second operative site for harvest
                       - Compared to OATs or Mosaicplasty
               - Single surgical procedure
                       - Compared to Autologous Chondrocyte Transplants (Carticel)

       - Risks
               - Transmission of Disease
               - Immune Response
               - Resorption and fragmentation of the graft
               - Procedure-based risk
                       - Osteotomy Non-union
                       - Post-op Arthritis



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, January 7, 2013 2:14 pm