Symptomatic osteochondral lesions of the talus remain a challenging problem due to inability for cartilage lesions to heal. Numerous treatment options exist, including nonoperative management, marrow stimulating techniques, and autograft-allograft. Arthroscopic marrow stimulation forms fibrocartilage that has been shown to be biomechanically weaker than hyaline cartilage. Restorative tissue transplantation options are being used more for larger and cystic lesions. Newer biologics and particulated juvenile cartilage are currently under investigation for possible clinical efficacy. This article provides an evidenced-based summary of available literature on the use of biologics for treatment of osteochondral lesions of the talus.
Key points
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Larger osteochondral lesions of the talus greater than 1.5 cm 2 have increased risk for healing complications.
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Osteochondral autograft transfer improves functional outcomes and pain scores in medium to short-term periods.
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Most of the success rate of osteochondral allografts is based on retrospective case series with limited outcome data.
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Autologous chondrocyte implantation has been shown to improve American Orthopedic Foot and Ankle Society scores but most studies do not correlate results with specific characteristics of the lesion.
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There are limited clinical data to support the use of platelet rich plasma, hyaluronic acid, bone marrow aspirate concentrate, or juvenile cartilage for osteochondral lesions of the talus.
Introduction
Osteochondral lesions of the talus (OLTs) are more common than previously thought. They are associated with trauma and are frequently involved in patients presenting with ankle sprains or fractures. The range of OLTs occurring after ankle trauma has been reported to be between 10% and 75%.
Diagnosis can be difficult because plain radiographs may miss more than half of osteochondral lesions. On clinical examination, there is not a specific test that is diagnostic for osteochondral lesion of the talus. Patients may present with diffuse nonspecific tenderness, or the pain may be more specific over the medial or lateral talus. Computed tomography (CT) and MRI are frequently used for the evaluation of suspected OLT. MRI is typically preferred for assessing the integrity of the overlying cartilage in nondisplaced lesions. CT scans are better at showing cystic lesions that may be overestimated with the edema seen on MRI. In addition, CT scans have been reported to be more accurate at determining lesion size.
Various classification schemes have been devised, with some based on radiographic findings and some based on intraoperative arthroscopic findings regarding the condition of the osteochondral fragment. The Berndt and Harty classification is based on plain radiography ( Box 1 ), the Hepple classification is based on MRI, and the Ferkel and Sgaglione classification is based on CT scan.
Stage I: subchondral compression (fracture)
Stage II: partial detachment of osteochondral fragment
Stage III: completely detached fragment without displacement from fracture bed
Stage IV: detached and displaced fragment
Stage V: subchondral cyst present
After diagnosis of a symptomatic OLT, initial treatment is nonoperative. This may include anti-inflammatories, immobilization, and protected weightbearing. The main contraindication to nonoperative treatment is an acute injury with displacement. In these cases, prompt operative management is indicated to either resect or perform reduction and internal fixation of the fragment.
Surgical intervention is indicated for the remainder of osteochondral lesions that have failed conservative management. Bony or ligament reconstruction may also be necessary at time of surgery. Ankle arthroscopy is the most common treatment modality for OLT. Often, the osteochondral lesion is treated with debridement or marrow stimulation. Penetration of the subchondral plate leads to release of mesenchymal stem cells and growth factors that forms a clot that develops into fibrocartilage. This type-I collagen has different biomechanical properties than native articular hyaline cartilage, which is composed primarily of type-II collagen. Debridement and marrow stimulation have been well reported in the literature and shown to be effective for lesions less than 1.5 cm 2 . This cutoff of 1.5 cm 2 is based on several prior studies, and lesion size has been accepted widely as the most commonly used predictor of clinical outcomes after bone marrow stimulation for OLT. However, recent literature has failed to detect a significant correlation between lesion size and clinical outcomes after bone marrow stimulation. In fact, a recent systematic review found that lesion sizes greater than 107.4 mm 2 and 10.2 mm in diameter are significantly correlated with poorer clinical outcomes. The investigators reported that the variability in calculating lesion size area makes the current cutoff of 1.5 cm 2 inaccurate.
Arthroscopic treatment of osteochondral lesions has been associated with worse outcomes for large cystic lesions. Shoulder lesions of the talus are also challenging because the curved geometry is hard to reproduce. Uncontained osteochondritis dissecans (OCD) of the talar shoulder have more complicated clinical outcomes than those with a contained nonshoulder lesion. In these cases, restorative tissue transplantation options include use of autograft, allograft, autologous chondrocyte implantation (ACI), and juvenile cartilage allograft transplantation. This article focuses on these transplantation options and seeks to provide an up-to-date evidence-based summary of the literature.
Introduction
Osteochondral lesions of the talus (OLTs) are more common than previously thought. They are associated with trauma and are frequently involved in patients presenting with ankle sprains or fractures. The range of OLTs occurring after ankle trauma has been reported to be between 10% and 75%.
Diagnosis can be difficult because plain radiographs may miss more than half of osteochondral lesions. On clinical examination, there is not a specific test that is diagnostic for osteochondral lesion of the talus. Patients may present with diffuse nonspecific tenderness, or the pain may be more specific over the medial or lateral talus. Computed tomography (CT) and MRI are frequently used for the evaluation of suspected OLT. MRI is typically preferred for assessing the integrity of the overlying cartilage in nondisplaced lesions. CT scans are better at showing cystic lesions that may be overestimated with the edema seen on MRI. In addition, CT scans have been reported to be more accurate at determining lesion size.
Various classification schemes have been devised, with some based on radiographic findings and some based on intraoperative arthroscopic findings regarding the condition of the osteochondral fragment. The Berndt and Harty classification is based on plain radiography ( Box 1 ), the Hepple classification is based on MRI, and the Ferkel and Sgaglione classification is based on CT scan.
Stage I: subchondral compression (fracture)
Stage II: partial detachment of osteochondral fragment
Stage III: completely detached fragment without displacement from fracture bed
Stage IV: detached and displaced fragment
Stage V: subchondral cyst present
After diagnosis of a symptomatic OLT, initial treatment is nonoperative. This may include anti-inflammatories, immobilization, and protected weightbearing. The main contraindication to nonoperative treatment is an acute injury with displacement. In these cases, prompt operative management is indicated to either resect or perform reduction and internal fixation of the fragment.
Surgical intervention is indicated for the remainder of osteochondral lesions that have failed conservative management. Bony or ligament reconstruction may also be necessary at time of surgery. Ankle arthroscopy is the most common treatment modality for OLT. Often, the osteochondral lesion is treated with debridement or marrow stimulation. Penetration of the subchondral plate leads to release of mesenchymal stem cells and growth factors that forms a clot that develops into fibrocartilage. This type-I collagen has different biomechanical properties than native articular hyaline cartilage, which is composed primarily of type-II collagen. Debridement and marrow stimulation have been well reported in the literature and shown to be effective for lesions less than 1.5 cm 2 . This cutoff of 1.5 cm 2 is based on several prior studies, and lesion size has been accepted widely as the most commonly used predictor of clinical outcomes after bone marrow stimulation for OLT. However, recent literature has failed to detect a significant correlation between lesion size and clinical outcomes after bone marrow stimulation. In fact, a recent systematic review found that lesion sizes greater than 107.4 mm 2 and 10.2 mm in diameter are significantly correlated with poorer clinical outcomes. The investigators reported that the variability in calculating lesion size area makes the current cutoff of 1.5 cm 2 inaccurate.
Arthroscopic treatment of osteochondral lesions has been associated with worse outcomes for large cystic lesions. Shoulder lesions of the talus are also challenging because the curved geometry is hard to reproduce. Uncontained osteochondritis dissecans (OCD) of the talar shoulder have more complicated clinical outcomes than those with a contained nonshoulder lesion. In these cases, restorative tissue transplantation options include use of autograft, allograft, autologous chondrocyte implantation (ACI), and juvenile cartilage allograft transplantation. This article focuses on these transplantation options and seeks to provide an up-to-date evidence-based summary of the literature.
Osteochondral autograft transplantation system
Osteochondral autograft transplantation system (OATS) involves harvesting cylindrical blocks of cartilage and bone from a donor site such as
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Trochlea and sulcus terminalis of the ipsilateral knee
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Superolateral aspect of the lateral femoral condyle ( Fig. 1 )
Fig. 1
Autologous osteochondral transplantation harvested from the knee. One or more cylindrical grafts are transplanted into the talar lesion, taking care to keep the articular surface congruent.
( From Murawski CD, Kennedy JG. Operative treatment of osteochondral lesions of the talus. J Bone Joint Surg Am 2013;95(11):1049; with permission.)
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Ipsilateral distal tibia
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Ipsilateral talus.
Although osteochondral autologous transplantation has traditionally been used as salvage for failed primary treatment, its use as the primary procedure has been supported by several studies. Benefits of OATS allows for bony healing with hyaline cartilage and no concern for an immune response destroying the graft. Disadvantages include donor site morbidity and the possible need for an osteotomy to expose the lesion. Nonunion and delayed union of the osteotomy is reported to occur at a rate between 0% and 2%. Because OATS is more common in the knee, it is not uncommon to request the help of a knee surgeon who can help with harvest of the graft.
Gobbi and colleagues performed a randomized controlled trial comparing outcomes of chondroplasty versus microfracture versus osteochondral autologous transplantation in subjects with symptomatic OLTs. Mean time to follow-up was 53 months. Mean lesion size ranged from 3.7 cm 2 to 4.5 cm 2 . OATS was shown to have similar outcome scores when compared with chondroplasty and microfracture at 2-year follow-up. American Orthopedic Foot and Ankle Society (AOFAS) scores were 85 in 12 subjects with grade 3 or 4 lesions treated with autograft taken from the ipsilateral knee. However, the OATS group had significantly higher numeric pain intensity scores postoperatively when compared with the other 2 modalities. The investigators recommended chondroplasty or microfracture as first-line surgical treatment of patients with OLT.
Multiple studies have investigated the use of OATS for OLT. Most demonstrate improvement in AOFAS score and low incidence of complication ( Table 1 ).
| Study | Number of Subjects | Follow-up | Donor Site | Outcome | Results |
|---|---|---|---|---|---|
| Sammarco & Makwana, 2002 | 12 | 25 mo | Talus | AOFAS improved from 64 to 90 | AOFAS scores higher in subjects <40 y All subjects very satisfied No donor site complications |
| Emre et al, 2012 | 32 | 24 mo | Knee | AOFAS improved from 59 to 88 | Open mosaicplasty is reliable for OCD with subchondral cysts >1.5 cm diameter |
| Imhoff et al, 2011 | 26 | 84 mo | Knee | AOFAS improved from 50 to 78 VAS decreased from 7.8 to 1.5 | Normal integration of transplant on MRI did better OATS as a 2nd procedure had worse clinical AOFAS and higher VAS |
| Hu et al, 2013 | 16 | 32.6 mo | Iliac crest | VAS decreased from 5.5 to 1 AOFAS improved from 75 to 90 | 7 subjects resumed sporting activities 7 excellent, 8 good, and 1 fair results |
| Kim et al, 2012 | 52 | 13.1 mo | Knee | AOFAS improved from 67 to 83 VAS improved from 6.9 to 3.3 | 1 required scope 13 mo later with soft tissue impingement |
| Hintermann et al, 2015 | 14 | 4.1 y | Knee | AOFAS increased from 65 to 81 VAS decreased from 5.8 to 1.8 | Vascularized bone graft from femur can restore contour of talus |
| Chen et al, 2015 | 15 | 24 mo | Talus | AOFAS increased from 49 to 89 VAS decreased from 5 to 1 MOCART was 64 | Autograft from medial tibia can treat large cystic OCD lesions |
| de l’Escalopier et al, 2015 | 37 | 76 mo | Knee | AOFAS postoperatively was 83 Work-related accident related with poorer result | Mosaicplasty gives good midterm outcomes in 78% |
| Scranton & McDermott, 2001 | 50 | 36 mo | Knee | 90% with good to excellent score 1 subject with impingement that improved after release | Cystic stage V lesion can be treated with OATS |
| Kreuz et al, 2006 | 35 | 49 mo | Talus | AOFAS improved by 39 points without osteotomy and 30 points with osteotomy No nonunions of osteotomy | Tibial wedge osteotomy is good alternative for malleolar osteotomy |
| Lee et al, 2003 | 17 | 36 mo | Knee | 89% excellent and 11% good results Second-look arthroscopy in 16 ankles revealed congruity in 88% | OATS can treat advanced-stage OCD of talus |
| Al-Shaikh et al, 2002 | 19 | 16 mo | Knee | AOFAS postoperatively score was 88 Lysholm knee score was 97 2 with mild knee pain | OATS effective for salvage surgery |
| Flynn et al, 2016 | 85 | 47 mo clinical 25 mo MRI | Knee | FAOS improved from 50 to 81 | OATS effective for large OCLs of the talus and MOCART scoring indicated good structural integrity of the graft |
Multiple studies have evaluated donor-site knee pain after osteochondral graft harvest. Although there are some data on poorer results in patients with increased body mass index, most data reports a relatively low incidence of morbidity with good clinical scores.
The ability of patients to return to sporting activities has also been studied. Paul and colleagues studied 131 subjects who were followed retrospectively for a mean of 60 months postoperatively after autologous osteochondral transplantation. Although subjects were able to return to sporting activities, there was a reduction of participation in high-impact and contact sports. The investigators also noted that both the surgical site and donor site morbidity could contribute to reduction in sporting activities due to concern about an excessive load or the risk of trauma to the ankle or the morbidity of the graft harvest at the knee.
OATS may also be done for revision OCD surgery. One study showed that primary OATS show better functional outcomes versus secondary OATS after failed microfracture. Their cohort consisted of 22 subjects with primary and 54 subjects with secondary OATS. The postoperative Foot and Ankle Outcome Score (FAOS) was 10 points higher in the primary group.
Osteochondral allograft transplantation
Osteochondral allograft transplantation is more frequently used when the OLT is too large to fill with autograft. It is a single-stage procedure in which a cadaver graft of viable articular cartilage and underlying subchondral bone are matched to the osteochondral defect. Fresh allografts are typically preferred due to decreased chondrocyte viability in the donor tissue having been reported in both fresh-frozen and cryopreserved allografts. Due to allografts being hypothermically stored for a minimum of 14 days as a result of safety concerns over infection and viability of chondrocytes having been shown to decrease after 28 days postmortem, it is recommended that the fresh osteochondral allografts be used between 15 and 28 days postmortem, ideally at day 15 to 16 to maximize chondrocyte viability. Fig. 2 shows allograft harvest and fixation to talus.
The biggest advantage is that it easier to match the unique shape of the talus with the allograft. Disadvantages include
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Limited availability of graft because the patient and surgeon must wait for a size-matched talus
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Time-sensitive nature of surgery because the fresh allograft should be implanted 14 to 21 days after harvest
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Concerns of disease transmission or immunologic factors.
Donors are screened for diseases such as human immunodeficiency virus, hepatitis, prion disease, and syphilis. Regarding immunologic factors, Pomajzl and colleagues reported on 8 failed allografts and thought that biologic causes were likely responsible for failure. They suspected possible CD4+ and CD8+ lymphocyte-mediated failure.
Fresh allografts are the most commonly used in practice and the literature on osteochondral allografts mostly comprises retrospective studies. When interpreting the data, one must remember than allograft is typically used on larger lesions with more cystic characteristics. Table 2 shows studies looking at allograft transplant of talar OCD.
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