The Hip
Home » Joints » Ankle » Osteochondral Lesions of the Talus – Allograft Repair

Osteochondral Lesions of the Talus – Allograft Repair


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


Autologous osteochondral grafting of the Talus is normally reserved as a secondary procedure after a failed arthroscopic microfracture of the osteochondral defect.

Though there is some evidence that the high grade lesions  do less well with an arthroscopic debridement and microfracture, this is a much smaller operation than open grafting and is therefore a reasonable starting point for surgical intervention.

The grafts used in this technique are cylindrical plugs “cored” out of a peripheral part of the ipsilateral knee, which can lead to secondary knee pain in some patients.

Sizing of the cylindrical grafts required(noting diameter and depth) precedes removal of the defect in this fashion, into which one or more cylindrical grafts from the knee are carefully impacted.

It is key that the Osteochondral grafts are placed as precisely (and flush) with the existing articular surface as possible, which in most cases means a malleolar osteotomy will be required to allow exact placement.

Secondary interventions are also on occasion required post grafting, such as steroid injection and on occasion further arthroscopy, and a return to normal and full function is not likely for at least 6 months post surgery.

Broadly speaking success rates of 85% or so can be anticipated, and in the longer term, as with all osteochondral surgery more minor symptoms may persist and late deterioration can occur.

OrthOracle readers will also find on interest the following associated instructional operative techniques:

Ankle arthroscopy using the Smith and Nephew Guhl non-invasive ankle distractor

HAMIC and Medial malleolar osteotomy for Osteochondral defect of talus, using Chondrotissue by Biofuse.

Stem cell harvest and transplant for knee osteochondral defect (Synergy Medical technologies)

Knee arthroscopy and microfracture of osteochondral defect

Read more »

This overview is brought to you by Orthoracle - the online e-learning Orthopeadic Surgery Atlas

Take the Tour

View this procedure in full

Osteochondral Lesions of the Talus Review

Etiology
- Primary Causes
- Trauma
- Ischemic Necrosis
- Embolic phenomenon
- Ossification Defects
- Predisposing Factors
- Endocrine Disorders
- Peripheral vascular disease
- Genetic Predisposition?
- 10-25% Bilateral Lesions

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

Treatment Plan
- Acute vs. Chronic symptoms
- Radiographic Staging / Severity of Lesion
- Location of the Lesion
- Quality of Subchondral Bone
- Ankle Instability
- Prior Interventions

Treatment Modalities
- Non-Tissue Transplantation
- Activity Restriction
- Internal Fixation
- Arthroscopy
- Excision
- Curettage / Abrasion
- Drilling
- Micro-fracture

- Tissue Transplantation
- Modalities
- Autologous Bone Grafting
- Autologous Chondrocyte Transplantation
- Carticel
- Osteochondral Autograft Transplantation (OATs)
- Single Osteochondral Plug
- Mosaicplasty
- Osteochondral Allograft Transplantation
- Benefits
- Provides the ability to fill in a larger defect
- Provides an articulating surface
- Prevents excessive weight bearing loads on the remaining portion of the talus which would accelerate ankle joint arthritis


Osteochondral Allograft Transplantation
- Allograft Transplantation is proving to be beneficial for large osteochondral defects where duplication of the anatomy would be difficult with autologous tissue.
- Osteochondral Autograft Transplantation Limitations
- Lesion size = Limited “extra” cartilage
- Only Carticel can fill irregular shaped lesions
- Flat surface required
- Attempts at angular repairs have been challenging

- Allograft Talus is size matched = Custom fit
- Able to treat the “shoulder lesion”
- Defect involving more than one articulating plane (Figure 1)

- Allograft 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)

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

- Specimens
- Tissue Banks uphold strict guidelines and protocol established by American Association of Tissue Banks
- Allograft procurement is performed in patients 18 - 45y within 24h
- Transplantation occurs with 72 hours for fresh grafts
- Extension for up to 5 - 7 days has been reported
- Donor patients are screened to eliminate possible disease transmission.
- Extensive medical and social histories
- Multiple Cultures and serologic studies are performed
- Articular cartilage is examined in a class-100 clean room
- Particle count < 100 particles per cubic foot of a size 0.5µ (micron) and larger.

- Fresh vs. Fresh-Frozen Allograft
- Storage
- Fresh grafts  = 4 degrees Celsius in Ringers lactate
+/- Antibiotics (Ancef, Bacitracin) added to the milieu
+/- Cryopreservative (dimethylsulfoxide DMSO, glycerol)
- Frozen Grafts  = -70  -80 degrees Celsius
+ Cryopreservative
- Differing Chondrocyte Viability

- Ohlendorf, et al (1996)
- Studied effects of Cryopreservation to -80 deg on Calf Cartilage using con-focal and conventional fluorescent microscopy
- Rapid freezing (2 deg/min)  = non-viable chondrocytes
- Slow freezing (0.5 deg/min)  = superficial chondrocyte layer viable only
- Slow freezing with cryopreservative  = superficial chondrocyte layer viable only
- Chondrocyte survival in cryopreserved osteochondral articular cartilage.

- Rodrigo, et al (1987)
- Compared rat chondrocyte viability in fresh vs. fresh-frozen osteochondral allografts
- Chondrocytes stored at 4 deg had 75% viability in 24 hours, and 47% at 48 hours
- Bone viability declined rapidly to 10% in 24 hours
- Significant decline in viable chondrocytes after freezing
- 8/10 specimens had 0% viability
- 2/10 showed almost 100% viability
- Immunogenicity also declined with freezing
- Deep-freezing versus 4 degrees preservation of avascular osteocartilaginous shell allografts in rats.

- Differing Immunogenic response
- Chondrocytes are imbedded in Hyaline Matrix
- By nature of location inside a synovial joint are somewhat immunopriveleged.1
- Presently, there are no requirements to immunologically match donor and host
- Acute rejection has thus far not been a clinical problem
- Marrow depletion is necessary via high pressure pulse lavage prior to implantation

- Stevenson, et al. (1989)
- Evaluated allograft cartilage implanted in dogs
- 4 categories based on Canine Leukocyte antigen matching and fresh vs. cryopreserved grafts
- Antigen mismatched Frozen
- Antigen mismatched Fresh
- Antigen matched Frozen
- Antigen matched Fresh
- No dog had any noticeable clinical abnormality
- All cartilage specimens were thinned
- Inflammatory response in synovium most severe in Fresh, Antigen mismatched allografts
- The worst specimen was seen in Frozen, antigen mismatched
- Both histologically & biochemically
- Fresh Antigen matched grafts performed the best
- The fate of articular cartilage after transplantation of fresh and cryopreserved tissue-antigen-matched and mismatched osteochondral allografts in dogs.

- Allograft Choice
- Most Literature is leaning towards the use of Fresh Osteochondral Allograft
- Based on the viability of the chondrocytes and the maintenance of the cartilage matrix
- Grafts that have shown to be most viable when they are slow cooled to 4 deg Celsius and preserved

- Outcomes
- Literature has cited its use in Berndt and Harty Stage II, III, and IV lesions.

- Thomas, et al (1997)
- Fresh-frozen Talar allograft
- Used during reconstruction for a benign osteochondral tumor of the talar dome.
- 18 months s/p surgery pt was participating in normal activity pain free.
- Repair of an osteochondral tumor of the talus utilizing a fresh-frozen cadaveric graft.

- Gross, et al (2001)
- Evaluated 9 cases Clinically and Radiographically
- Pre-op:  All subjects had an area of Fragmentation and Collapse that could not be reattached
- Lesion at least 1 cm in diameter / 5 mm in depth
- All patients had prior procedures
- Average graft life = 9 years (3 – 19)
- 3/9  patients required fusions at 3, 5, 9 years out for graft fragmentation and collapse
- 6 pts with intact grafts required no assistive device
- 5 / 6 had no pain; 1 /6 had mild intermittant pain
- Osteochondral defects of the talus treated with fresh osteochondral allograft transplantation.

- Caylor and Pearsall (2002)
- Case report:  16-year-old female with 3 years pain after ankle sprain
- 2 Allograft Bone plugs used to treat a 18mm x 18mm lesion on posteromedial talus
- Post – op Protocol
- Immobilized 2 weeks
- ROM exercise only from 2 – 6 weeks
- Partial weight bear 6 – 12 weeks
- Full weight bear from 12 – 20 weeks
- Unlimited activity at 20 weeks
- F/U at 1 year, patient had no pain or limitations
- Fresh osteochondral grafting in the treatment of osteochondritis dissecans of the talus.


Surgical Technique - Lateral
- Care to avoid damage to the Sural n. & Peroneal artery posteriorly, & superficial peroneal n. anteriorly.
- Removal of Osteophytes at Talofibular Joint
- Fibular Osteotomy - Pre drill holes for plate
- Removal of Osteochondral Lesion and Curettage
- Preparation of Graft Site
- Template (Figure 2)

- Allograft Placement (Figure 3)

- Articulation Testing and Screw Fixation with Countersinking
- Osteotomy Repair
- Intra-operative Radiographs (Figures 4 & 5)

Surgical Technique - Medial
- Utilizes Medial Malleolar Osteotomy (Figure 6)

 


Summary
- Cartilage injuries and Osteochondral Lesions of the talus remain a challenge within Orthopaedics
- MRI & CT scan is useful with identifying and defining pathology in patients with suspected lesion
- Arthroscopy is the Gold Standard for diagnosis and treatment planning
- For large, abnormally positioned lesions, or those that have failed prior intervention, Allograft Transplantation is a promising treatment modality
- Further investigation and research is still needed in regards to
- graft storage options
- long term immunologic reactions
- clinical outcomes