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Osteochondral lesion of the talus

63 citationsUpdated Oct 2026
Illustration: ankle

For patients: a plain-language version of this topic is available. See the patient guide.

Overview

Osteochondral lesions of the talus present a clinical spectrum where initial nonoperative management, when successful, is associated with minimal long-term symptoms, a low failure rate, and no relevant progression of ankle osteoarthritis [1]. However, most patients with symptomatic or unstable lesions require surgical intervention [4]. Initial defect size serves as an important and easily obtainable prognostic factor that may guide preoperative surgical decisions [7]. While many reasonable operative techniques exist and most lead to similar and satisfactory results [4], current literature does not support the interchangeability of treatments for primary defects [18]. Treatment selection depends on specific lesion characteristics, including diameter, surface area, depth, and location [15], with different techniques indicated based on size, depth, and cartilage integrity [18]. Although all analyzed treatment options were effective with no differences found in terms of score improvements [3], future high-level controlled studies are needed to explore advantages and disadvantages for specific indications [18].

Operative management encompasses both reparative and restorative options [15]. Arthroscopic debridement and microfracture provide a good long-term option for select patients [5] and are safe and effective for isolated lesions [6]. Specifically, arthroscopic microfracture provides excellent or good clinical outcomes in 89% of patients younger than 50 years with lesions of ≤1.5 cm2 at an average follow-up of 33 months [6]. This technique yields similar good clinical outcomes for both chondral and osteochondral lesions [2] as well as for non-traumatic and traumatic etiologies [8]. For talar head lesions, arthroscopic management offers advantages of better cosmetic results, less pain, and less surgical trauma, though it is technically demanding and should be reserved for experienced foot and ankle arthroscopists [24].

Restorative techniques offer alternatives for complex or failed cases. Autologous chondrocyte implantation yields improvement in all parameters tested with enduring long-term results in patients who have failed previous surgery [10], although evidence concerning its use for talar defects remains elusive [27]. Osteochondral autologous transplantation was significantly superior to repeat arthroscopic treatment after a mean follow-up of 48 months [13] and can be safely used after failure of primary bone marrow stimulation [14]. The all-arthroscopic AMIC technique allows precise reconstruction while avoiding the morbidity and longer surgical time of more invasive operations [25]. For large medial talar dome lesions, the TOPIC procedure is effective, resulting in significant improvement exceeding the minimal clinically important difference in pain scores and 100% graft consolidation [38]. Fresh OCA transplantation is a reasonable option for young, active patients who have failed non-operative management [54], and arthroscopic cell-free osteochondral scaffolds appear effective for localized disease [16]. Future management should aim for primary preventive interventions and an individualised approach focusing on optimal tissue engineering requirements [23].

Anatomy & Pathophysiology

Etiology

The etiology of osteochondral lesions of the talus (OLTs) is not yet clearly understood [11]. The term osteochondritis dissecans may imply an inflammatory disease, which is most likely not the case [11]. Various etiological theories exist, including repetitively microtraumatic, ischemic, hereditary, or idiopathic etiologies [11]. The leading thought on the etiology of osteochondral lesions entails a multifactorial combination of microtraumatic, ischemic, hereditary, and idiopathic factors [11]. Ischemia during the endochondral ossification of the epiphyseal cartilage may result in the development of an osteochondral lesion [11]. Epiphyseal cartilage is supplied with nutrients through cartilage canals that normally close when the cartilage ossifies and matures [11]. Failure of the closure process due to instability of anastomoses between epiphyseal cartilage and mature bone can lead to avascular necrosis [11]. Instability of anastomoses occurs due to poor neoangiogenesis [11]. A stable osteochondral lesion can destabilize after the fragment detaches following an ankle trauma, becoming symptomatic [11].

The etiological theory of repetitive microtrauma is biomechanically similar to the etiological mechanism of a traumatic osteochondral lesion [11]. In osteochondral lesions caused by repetitive microtrauma, the damage cascade presumably starts with subchondral stress, disabling the subchondral bone to intercept ongoing trauma and damaging the overlying cartilage [11]. Forced-dorsiflexion ankle positions during activities such as horseback riding can cause repetitive microtraumas leading to osteochondral lesions [11]. Genetic factors may play a role in the etiology of osteochondral lesions [11]. Most studies report a history of trauma as the main cause for developing an osteochondral lesion of the talus [28]. Osteochondral lesions are especially common after acute and chronic ankle sprains [28]. The impact of multiple forces leads to a cartilage contusion, which may be transmitted to the subchondral bone, causing subchondral microfractures progressing to an osteochondral lesion or subchondral cyst [28]. Metabolic diseases, genetic predisposition, vascular or synovial alterations, or chronic microtraumas are cited among the causes of osteochondral lesion development [28].

Trauma is the most common cause of osteochondral lesions of the talar dome [31]. Ischemic necrosis, endocrine disorders, and genetic factors may have etiologic significance in osteochondral lesions of the talar dome [31]. Osteochondral lesions of the talus are most commonly attributed to trauma [51]. Lateral talar dome lesions have a traumatic etiology more often than medial lesions [51]. Biomechanical studies indicate that a repetitive overuse syndrome may be responsible for medial osteochondral lesions [51]. Biomechanical studies support the belief that acute trauma causes lateral osteochondral lesions [51].

Injury Mechanisms and Location

The mechanism of injury for lateral osteochondral lesions is inversion and dorsiflexion, in which the anterolateral aspect of the talus impacts the fibula [51]. Medial osteochondral lesions result from combined inversion, plantar flexion, and external rotational forces [51]. The medial osteochondral lesion is typically deep and cup-shaped, caused by the posteromedial talar dome impacting the tibial articular surface [51]. Medial osteochondral lesions are usually located posteriorly on the dome of the talus [31]. Lateral osteochondral lesions are most frequently located anteriorly [31].

Pathophysiology and Pain

Osteochondral defects of the ankle can either heal and remain asymptomatic or progress to deep ankle pain on weight bearing and formation of subchondral bone cysts [57]. The development of a symptomatic osteochondral defect depends on various factors, including the damage and insufficient repair of the subchondral bone plate [57]. The ankle joint has a high congruency [57]. During loading, compressed cartilage forces its water into the microfractured subchondral bone, leading to a localized high increased flow and pressure of fluid in the subchondral bone [57]. Localized high fluid pressure in the subchondral bone results in local osteolysis and can explain the slow development of a subchondral cyst [57]. Pain from osteochondral defects does not arise from the cartilage lesion but is most probably caused by repetitive high fluid pressure during walking, which stimulates the highly innervated subchondral bone underneath the cartilage defect [57]. Understanding the natural history of osteochondral defects could lead to the development of strategies for preventing progressive joint damage [57].

The "ankle cartilage cascade" concept proposes that various pathophysiological pathways induce cartilage damage potentially leading to osteoarthritis [101]. Early detection and preventive interventions in the subclinical phase are advocated to stall the ankle cartilage cascade [101]. Addressing chronic lateral ankle instability simultaneously with osteochondral lesion of the talus treatment may positively impact the long-term health of the ankle joint by protecting repaired cartilage and stopping the cascade of cartilage damage [21].

Prognosis and Natural History

Osteochondral lesions of the talus that successfully underwent an initial nonoperative treatment period had a low failure rate [1]. Osteochondral lesions of the talus that successfully underwent an initial nonoperative treatment period showed no relevant ankle osteoarthritis progression [1]. Whether an osteochondral lesion of the talus is a precursor to more generalised arthrosis of the ankle remains unclear [53]. The condition is often symptomatic enough to warrant treatment [53]. In more than one third of cases, conservative treatment for osteochondral lesions of the talus is unsuccessful, and surgery is indicated [53]. Smaller osteochondral lesions are symptomatic and when left untreated, osteochondral lesions can progress [53]. Current treatment strategies have not solved the problem of progression in untreated smaller osteochondral lesions [53].

Biomechanics and Anatomy

The cartilage properties of the various topographic locations within the ankle are significantly different [61]. Opposing articulating surfaces within the ankle exhibit significantly different biomechanical and biochemical properties [61]. The dynamic congruency of the joint, which is influenced by ligamentous integrity, remains the main anatomical component in mechanical ankle instability [60]. The orientation of the posteroinferior talar facet was statistically significantly more plantarly orientated in the chronic ankle instability group compared to the control group [96]. The posteroinferior talar facet orientation in the chronic ankle instability group was 14.7 ± 3.1° compared to 11.2 ± 4.9° in the control group [96]. The effect size for the difference in posteroinferior talar facet orientation between chronic ankle instability and control groups was g = 0.76 [96]. Placement of the osteochondral graft in the most congruent position possible partially restored contact mechanics of the ankle joint [71]. Sliding calcaneal osteotomy reliably unloaded the medial compartment of the ankle joint for a neutral tibial axis [73]. The presence of the distal fascicle of the anterior inferior tibiofibular ligament and its contact with the talus is a normal finding that may become pathological due to anatomical variations or anterolateral instability [105].

Classification

Radiographic and Imaging Classifications

Berndt and Harty: This four-part radiographic system classifies osteochondral lesions of the talus based on fragment integrity [82]. Stage I is defined as a small subchondral trabecular compression fracture not seen radiographically [82]. Stage II involves an incomplete avulsion or separation of the fragment [82]. Stage III is characterized by complete avulsion without displacement [82]. Stage IV describes a fragment that is detached, rotated, and possibly within the joint [82]. While this classification may not accurately reflect the integrity of the articular cartilage [31], MRI allows for the identification of Stage I lesions [82].

CT Arthrography: A new CT arthrographic classification system for osteochondral lesions of the talus has demonstrated excellent inter- and intraobserver agreement [46].

Imaging Modalities: MRI or CT is the preferred imaging for complete evaluation of a suspected osteochondral lesion of the talus [82]. MRI findings in stable lesions include decreased signal intensity on T1-weighted images and either low or increased signal on T2-weighted images [82]. MRI is useful for assessing Stage II lesions for chondral and subchondral discontinuity indicating instability [82]. Both MRI and CT assess the continuity of cartilage and subchondral cortex as an indicator of stability [82]. Lesion depth can be evaluated using MRI or CT [82]. MRI may be most useful in assessing for the presence of subchondral cysts [82]. Computed tomography remains the imaging technique of choice when delineation of a bone fragment is desired [31]. Bone scintigraphy may show increased radionuclide uptake in the talar dome [31]. Small lesions of the talar dome may be present despite a normal appearance on plain radiography [31]. Signal intensity patterns and cyst size may progress or regress over time [82]; however, these are less reliable indicators of lesion stability than surface continuity [82].

Arthroscopic Classifications

Pritsch: This classification grades the articular cartilage overlying a talar lesion into three grades based on appearance [68]. Grade I indicates intact, firm, shiny cartilage [82]. Grade II indicates intact but soft cartilage [82]. Grade III indicates frayed cartilage [82]. There is a lack of correlation between the radiographic appearance of a talar osteochondral lesion and the findings at arthroscopy [68]. A lesion can progress from grade I to grade III in the Pritsch classification while under observation [68].

Cheng: This classification includes six stages for osteochondral lesions of the talus [45]. Stage 1 is defined as smooth, intact but soft or ballotable cartilage [45]. Stage 2 is defined as a rough surface [45]. Stage 3 is defined as fibrillation or fissuring [45]. Stage 4 is defined as a flap present or bone exposed [45]. Stage 5 is defined as a loose, undisplaced fragment [45]. Stage 6 is defined as a displaced fragment [45].

Other Considerations: MRI may overestimate stability in osteochondral lesions of the talus [82]. A combination of MRI assessment and arthroscopic examination may be required to determine stability and treatment requirements for osteochondral lesions of the talus [82].

Anatomical and Morphological Classification

Location: Medial osteochondral lesions of the talus are usually located posteriorly on the dome [31]. Lateral osteochondral lesions of the talus are most frequently located anteriorly [31]. The location of a talar osteochondral lesion correlates with the incidence of a coexisting tibial osteochondral lesion [20].

Zoning and Sizing: In the axial plane, the articular surface of the talar dome can be partitioned into six zones of equal area using a grid consisting of two columns and three rows [72]. Lesions with an area less than 150 mm² are classified as small [72]. Lesions with an area exceeding 150 mm² are categorized as large [72]. A contained osteochondral lesion is defined by intact articular cartilage borders surrounding the defect [72].

Clinical Presentation

Etiology and Pathogenesis

The etiology of osteochondral lesions of the talus is not yet clearly understood [11]. The exact aetiology of talar osteochondral lesions remains unclear [28]. Etiological theories include repetitively microtraumatic, ischemic, hereditary, or idiopathic causes [11]. The leading thought entails a multifactorial combination of microtraumatic, ischemic, hereditary, and idiopathic factors [11]. Instability of anastomoses between epiphyseal cartilage and mature bone due to poor neoangiogenesis can lead to avascular necrosis and the origin of a stable osteochondral lesion [11]. The etiological theory of repetitive microtrauma is biomechanically similar to the etiological mechanism of an ordinary traumatic osteochondral lesion [11]. In osteochondral lesions of the talus, the damage cascade presumably starts with subchondral stress, disabling the subchondral bone to intercept ongoing repetitive trauma and damaging the overlying cartilage [11]. Genetic factors may play a role in the etiology of osteochondral lesions of the talus [11]. Osteochondral lesions of the talus are especially common after acute and chronic ankle sprains [28].

Clinical Symptoms and Signs

Osteochondral lesions of the talar dome are relatively common causes of ankle pain and disability [31]. While osteochondral lesions of the talus can be asymptomatic [64], they primarily present as chronic ankle pain, which may decrease after activities [64]. Patients will possibly report a history of ankle injury, especially a single ankle sprain or multiple ankle sprains [64].

Physical Examination

During outpatient clinic examination, tenderness and swelling of the ankle joint are thoroughly evaluated [64]. The anterior drawer test and forced inversion test are performed during the physical examination for osteochondral lesions of the talus [64].

Imaging and Diagnosis

Magnetic resonance imaging is sensitive for identifying intraosseous abnormalities in the talus and reveals other types of soft-tissue lesions not visible on routine radiographic studies [31]. MRI is commonly applied to confirm the diagnosis of an osteochondral lesion of the talus, with assessment of the location, size, and grade of the defective area [64]. Computed tomography scans are taken before surgery to help evaluate the size of the osseous lesion in osteochondral lesions of the talus [64]. Plain radiographs are taken before surgery to help evaluate the progression of osteoarthritis in osteochondral lesions of the talus [64]. Osteochondral lesions of the tibial plafond are often associated with coexisting osteochondral lesions of the talus [22].

Investigations

Plain radiography: Stress inversion ankle roentgenograms should be considered in cases of talar osteochondritis dissecans [88]. Standard radiographs often fail to determine the specific location of the lesion, as anterior, middle, or posterior positioning is frequently difficult to identify on these images [29].

CT: CT scans in axial and coronal planes are used to locate talar osteochondral lesions, particularly when radiographic localization is inconclusive [29]. CT arthrography visualizes tissue growth in osteochondral defects of the talus after microfracture, with growth observed in most cases [19].

MRI: Magnetic resonance imaging is indicated when clinical symptoms persist after osteochondral transplantation, but it should not be a routine control [95]. Lesion size measured on MRI does not accurately reflect arthroscopic measurement in talar osteochondral lesions [30]. If an osteochondral lesion is within the accessible area through either approach as viewed on MRI or CT, it can be safely reached without a medial malleolar osteotomy [69].

Treatment

Non-Operative

Non-operative treatment is recommended as the first line of management following the initial diagnosis of an osteochondral lesion of the talus [74]. This conservative approach is clinically effective in 45% of patients [74]. Current evidence does not support the superiority or inferiority of any specific non-operative protocol over another from either a clinical or radiological perspective [74].

Operative

Indications: Initial defect size serves as an important and easily obtainable prognostic factor that may guide preoperative surgical decisions [7]. Current literature does not support the interchangeability of treatments for primary osteochondral defects, as different techniques have distinct indications based on lesion size, depth, and cartilage integrity [18]. Stage-I and Stage-II lesions should be treated non-operatively [58]. Stage-III medial lesions should be treated non-operatively initially but require surgery if symptoms persist [58]. Stage-III lateral and all Stage-IV lesions should be treated by early operation [58].

Surgical Approach / Technique: While many reasonable operative techniques exist for osteochondral lesions of the talus, most lead to similar and satisfactory results [4]. Arthroscopic microfracture is a safe and effective procedure that provides excellent or good clinical outcomes in 89% of patients younger than 50 years with lesions of ≤1.5 cm² at an average follow-up of 33 months [6]. Both arthroscopic subchondral drilling and microfracture are effective and reliable in treating small- to mid-sized osteochondral lesions of the talus, regardless of which technique is used [32]. A comprehensive four-step protocol including synovectomy, debridement and microfractures of the OCL, capsular shrinkage, and bracing and non-weightbearing for 21 days is a safe and clinically effective treatment option in patients with post-traumatic OCLs of the ankle [63]. Arthroscopic management of osteochondral lesions of the talar head offers advantages of better cosmetic results, less pain, and less surgical trauma, though the technique is technically demanding and should be reserved for experienced foot and ankle arthroscopists [24]. Arthroscopic management of osteochondral lesion of plantar medial talar head is technically demanding and should be reserved for experienced foot and ankle arthroscists [36].

Implant Selection: The TOPIC procedure for large osteochondral lesions of the medial talar dome is an effective technique that resulted in significant improvement exceeding the minimal clinically important difference in pain scores as well as in other outcomes, with 100% consolidation of the grafts [38]. Arthroscopic ACI can repair osteochondral lesions in the ankle joint with satisfactory clinical results after mid-term follow-up [42]. Autologous chondrocyte implantation of the talus yields significant functional improvement; however, further investigation is necessary to determine the long-term structural and biomechanical properties of the repair tissue [49]. AMIC for osteochondral talar lesions led to significant pain reduction, recovery of ankle function, and successful return to sport [67]. The all-arthroscopic AMIC technique for the treatment of osteochondral lesions of the talus allows a very precise reconstruction in the case of cartilage defects and avoids the need for a more invasive operation associated with higher morbidity and a longer surgical time [25].

Other Considerations: Surgical treatment consisting of drilling and curettage followed by non-weight-bearing and early range-of-motion exercises yields a good long-term result for transchondral fractures of the talar dome [52]. For early stages and medial lesions or lesions in children that have not healed, percutaneous arthroscopic drilling has been recommended to promote healing [45]. Arthroscopic drilling for the treatment of medial osteochondral lesions of the talus does not require osteotomy of the medial malleolus or postoperative immobilization [45]. Arthroscopic drilling for the treatment of medial osteochondral lesions of the talus allows early resumption of daily activities and sports [45]. A specific indication for arthroscopic drilling is an early lesion with only mild osteosclerosis of the surrounding talar bone, continuity of the cartilaginous surface, and stability of the osteochondral fragment [45]. Retrograde percutaneous drilling through the sinus tarsi preserves the intact articular cartilage [45]. Bone grafts have been used in conjunction with retrograde drilling to prevent articular collapse due to the difficulty of adequately filling the contours of the lesion [45]. Surgical-grade calcium sulfate in a liquid form has been injected into the defect after drilling, and some authors have reported the use of a bone-marrow aspirate harvested from the iliac crest, centrifuged to isolate pluripotent cells, and mixed with the calcium graft to promote more rapid healing [45]. If osteotomy of the medial malleolus is necessary, surgery on the medial side should be delayed until after closure of the physis [29]. Patients are immobilized in a walking boot for 6 weeks and then allowed weight bearing in a walking boot until 12 weeks after surgery when osteotomy of the medial malleolus is used to approach a posteromedial lesion [45]. Numerous treatment strategies for symptomatic osteochondral lesions of the talus have advanced significantly, including reparative, replacement, and regenerative modalities [50].

Complications

Subchondral Bone Degeneration: Midterm follow-up of microfracture for osteochondral lesions of the talus demonstrates that subchondral bone is not restored [44]. A significant decrease in the overall subchondral bone height score occurs over time following this procedure [44]. Additionally, subchondral cysts deteriorate after microfracture for osteochondral lesions of the talus [44].

Other Considerations: Osteochondral transplantation of autologous talar graft can be safely and successfully used for osteochondral lesions of the talus following the failure of primary treatment with bone marrow stimulation [14].

Recovery

Operative

Other Considerations: Post-operative imaging and clinical follow-up data characterize the biological response to various surgical interventions for osteochondral lesions of the talus. Following microfracture, tissue growth within the defects is well visualized using CT arthrography and is observed in most cases [19]. Microfracture arthroplasty induces repair of localized articular cartilage defects, maintaining encouraging early results at mid-term follow-up [41]. However, the subchondral bones following microfracture are not restored at midterm follow-up, with a significant decrease in the overall SCBH score over time and deterioration of subchondral cysts [44]. Arthroscopic autologous chondrocyte implantation in the ankle joint repairs osteochondral lesions with satisfactory clinical results after mid-term follow-up [42]. A modified mosaicplasty procedure might be recommended for severe and recurrent osteochondral lesions of the talus and may lead to restoration of the subchondral bone stock, formation of fibro-cartilage, and stable joint function [26]. Treatment of osteochondral defects in the ankle and knee joint with a biomimetic scaffold resulted in incomplete cartilage repair and poor subchondral bone repair at 1- and 2.5-year follow-up [59].

Key Evidence

  • [L4] Osteochondral lesions of the talus that successfully underwent an initial nonoperative treatment period were associated with minimal symptoms in the long term, a low failure rate, and no relevant ankle osteoarthritis progression. [1] (10.1177/2325967120924183)
  • [L2] Both chondral and osteochondral lesions of the talus treated with arthroscopic microfracture showed similar good clinical outcomes. [2] (10.1007/s00167-014-3061-y)
  • [Paper] All analyzed treatment options were effective for osteochondral lesion of the talus treatment with no differences found in terms of score improvements. [3] (10.1007/s00402-020-03631-z)
  • [L5] Most patients with symptomatic or unstable osteochondral lesions of the talus require surgery, and while many reasonable operative techniques exist, most lead to similar and satisfactory results. [4] (10.1530/eor-22-0024)
  • [L4] Arthroscopic debridement and microfracture provide a good option for the treatment of osteochondral lesions of the talus over the long term in select patients. [5] (10.1007/s00167-016-3990-8)
  • [L4] Arthroscopic microfracture for isolated osteochondral lesions of the talus is a safe and effective procedure that provides excellent or good clinical outcomes in 89% of patients of less than 50 years old with lesions of ≤1.5 cm2 at an average follow-up of 33 months. [6] (10.1007/s00167-009-0914-x)
  • [L3] Initial defect size is an important and easily obtainable prognostic factor in osteochondral lesions of the talus and may serve as a basis for preoperative surgical decisions. [7] (10.1177/0363546509335765)
  • [L3] Arthroscopic microfracture treatment provides similar clinical outcomes in the case of non-traumatic and traumatic osteochondral lesions of the talus. [8] (10.1186/s12891-025-08949-6)
  • [L5] Arthroscopic management of osteochondral lesions of the talus is well documented with favorable results for reparative techniques. [9] (10.5435/00124635-200907000-00001)
  • [L4] Autologous chondrocyte implantation of the talus yields improvement in all parameters tested with enduring long-term results in patients who have failed previous surgery for osteochondral lesions of the talus. [10] (10.1177/0363546514540587)
  • [Case_report] [11] (10.1016/j.jisako.2023.05.002)
  • [L3] Osteochondral autologous transplantation was significantly superior to repeat arthroscopic treatment of osteochondral lesions of the talus after a mean follow-up period of 48 months. [13] (10.1177/0363546514535186)
  • [L4] The midterm results suggest that the technique of osteochondral transplantation of autologous talar graft for osteochondral lesions of talus after failure of primary treatment with bone marrow stimulation can be safely and successfully used. [14] (10.1007/s00167-014-3389-3)
  • [L5] Treatment selection for osteochondral lesions of the talus depends on lesion characteristics such as diameter, surface area, depth, and location, with various reparative and restorative surgical options available. [15] (10.1016/j.arthro.2021.10.002)
  • [L4] Arthroscopic cell-free osteochondral scaffold procedure appears to be an effective treatment with increasing the functional and quality of life, particularly in localized disease of the ankle joint such as talus osteochondral lesion. [16] (10.1177/2325967114s00160)
  • [Letter] Current literature does not support the interchangeability of treatments for primary osteochondral defects of the talus, as different techniques have different indications based on lesion size, depth, and cartilage integrity; future high-level controlled studies are needed to explore advantages and disadvantages for specific indications. [18] (10.1007/s00167-017-4700-x)
  • [L4] After microfracture of osteochondral lesions of the talus, tissue growth in the defects was well visualized using CT arthrography and was observed in most cases. [19] (10.1007/s00167-017-4610-y)
  • [L4] The location of a talar osteochondral lesion correlates with the incidence of a coexisting tibial osteochondral lesion. [20] (10.1177/2325967118790965)
  • [L5] Addressing chronic lateral ankle instability simultaneously with osteochondral lesion of the talus treatment may positively impact the long-term health of the ankle joint by protecting repaired cartilage and stopping the cascade of cartilage damage. [21] (10.1016/j.arthro.2025.02.005)
  • [L4] OLTPs are frequently preceded by ankle trauma and are often associated with coexisting osteochondral lesions of the talus. [22] (10.1177/23259671211029208)
  • [L5] Future management should aim for primary preventive interventions and an individualised approach focusing on optimal tissue engineering requirements to improve outcomes for osteochondral lesions of the talus. [23] (10.1007/s00167-019-05647-4)
  • [Paper] Arthroscopic management of osteochondral lesions of the talar head offers advantages of better cosmetic results, less pain, and less surgical trauma, though the technique is technically demanding and should be reserved for experienced foot and ankle arthroscopists. [24] (10.1016/j.eats.2019.05.006)
  • [Paper] The all-arthroscopic AMIC technique for the treatment of osteochondral lesions of the talus allows a very precise reconstruction in the case of cartilage defects and avoids the need for a more invasive operation associated with higher morbidity and a longer surgical time. [25] (10.1016/j.eats.2015.02.010)
  • [L4] This modified mosaicplasty might be recommended for severe and recurrent osteochondral lesions of the talus and may lead to restoration of the subchondral bone stock, formation of fibro-cartilage, and stable joint function. [26] (10.1007/s00167-013-2604-y)
  • [L1] Evidence concerning the use of ACI for osteochondral and chondral defects of the talus is still elusive. [27] (10.1007/s00167-011-1729-0)
  • [L5] [28] (10.1136/jisakos-2016-000099)
  • [L5] [31] (10.5435/00124635-199603000-00001)
  • [L3] The results of this study suggest that both techniques are effective and reliable in treating small- to mid-sized osteochondral lesions of the talus, regardless of which of the two techniques is used. [32] (10.1007/s00167-015-3511-1)
  • [Paper] This technique is technically demanding and should be reserved for experienced foot and ankle arthroscists. [36] (10.1016/j.eats.2018.09.001)
  • [L4] The TOPIC procedure for large osteochondral lesions of the medial talar dome is an effective technique that resulted in significant improvement exceeding the minimal clinically important difference in pain scores as well as in other outcomes, with 100% consolidation of the grafts. [38] (10.2106/jbjs.22.01322)
  • [L3] Microfracture arthroplasty induces repair of localized articular cartilage defects of the talus maintaining the encouraging early results at mid term follow-up. [41] (10.1007/s00167-009-1036-1)
  • [L4] This study confirmed the ability of arthroscopic ACI to repair osteochondral lesions in the ankle joint with satisfactory clinical results after mid-term follow-up. [42] (10.1007/s00167-013-2640-7)
  • [L4] The subchondral bones following microfracture for osteochondral lesions of the talus were not restored at midterm follow-up, with a significant decrease in the overall SCBH score over time and deterioration of subchondral cysts. [44] (10.1177/0363546517739606)
  • [L1] The study showed an excellent inter- and intraobserver agreement for the new CT arthrographic classification system of osteochondral lesions of the talus. [46] (10.1016/j.otsr.2021.102890)
  • [L4] Autologous chondrocyte implantation of the talus yields significant functional improvement; however, further investigation is necessary to determine the long-term structural and biomechanical properties of the repair tissue. [49] (10.1177/0363546508325670)
  • [L5] Numerous treatment strategies for symptomatic osteochondral lesions of the talus have advanced significantly, including reparative, replacement, and regenerative modalities, with future tissue engineering and gene therapy potentially influencing integration and longevity. [50] (10.1177/2325967119s00453)
  • [L4] [51] (10.1016/s0278-5919(03)00093-0)
  • [L4] [52] (10.2106/00004623-198062040-00020)
  • [Paper] [53] (10.1007/s00264-013-2076-1)
  • [L4] Fresh OCA transplantation is a reasonable surgical option for osteochondral defects of the talus for young, active patients who have failed non‐operative management. [54] (10.1177/2325967123s00093)
  • [L5] [57] (10.1007/s00167-010-1064-x)
  • [L4] Stage-I and Stage-II lesions should be treated non-operatively; Stage-III medial lesions should be treated non-operatively initially but require surgery if symptoms persist; Stage-III lateral and all Stage-IV lesions should be treated by early operation. [58] (10.2106/jbjs.l.00773)
  • [L4] Treatment of osteochondral defects in the ankle and knee joint with a biomimetic scaffold resulted in incomplete cartilage repair and poor subchondral bone repair at 1- and 2.5-year follow-up. [59] (10.1007/s00167-015-3538-3)
  • [L3] This supports the interpretation that the dynamic congruency of the joint, which is influenced by ligamentous integrity remains the main anatomical component in mechanical ankle instability. [60] (10.1186/s12891-025-09458-2)
  • [Paper] The cartilage properties of the various topographic locations within the ankle are significantly different, with opposing articulating surfaces exhibiting significantly different biomechanical and biochemical properties. [61] (10.1016/j.arthro.2014.05.025)
  • [L4] [63] (10.1007/s00167-012-2028-0)
  • [L5] [64] (10.1016/j.eats.2024.103208)
  • [L4] AMIC for osteochondral talar lesions led to significant pain reduction, recovery of ankle function, and successful return to sport. [67] (10.1177/0363546519841574)
  • [L4] [68] (10.2106/00004623-198668060-00007)
  • [L5] If the osteochondral lesion is within the accessible area through either approach as viewed on MRI/CT, it can be safely reached without a medial malleolar osteotomy. [69] (10.1007/s00167-009-1019-2)
  • [L5] Placement of the osteochondral graft in the most congruent position possible partially restored contact mechanics of the ankle joint. [71] (10.1177/0363546511419811)
  • [L3] [72] (10.1186/s13018-025-06232-x)
  • [L5] SCO reliably unloaded the medial compartment of the ankle joint for a neutral tibial axis. [73] (10.1177/23259671231176295)
  • [L4] [74] (10.1007/s00167-023-07408-w)
  • [L4] The case demonstrates that repeated inversion stress in ankles with lax lateral ligaments can result in osteochondral lesions of the medial part of the talus, and stress inversion ankle roentgenograms should be considered in cases of talar osteochondritis dissecans. [88] (10.2106/00004623-197052010-00018)
  • [L4] Magnetic resonance imaging should not be a routine control but appears to be indicated when clinical symptoms persist after osteochondral transplantation. [95] (10.1177/0363546510397726)
  • [L3] The orientation of the posteroinferior talar facet (TalusIF) was statistically significantly more plantarly orientated in the chronic ankle instability (CAI) group (14.7 ± 3.1°) compared to the control group (11.2 ± 4.9°), with a large effect size (g = 0.76). [96] (10.1002/jor.25068)
  • [L5] The paper proposes the 'ankle cartilage cascade' concept where various pathophysiological pathways induce cartilage damage potentially leading to osteoarthritis, and advocates for early detection and preventive interventions in the subclinical phase to stall this cascade. [101] (10.1007/s00167-021-06755-w)
  • [L5] The presence of the distal fascicle of the anterior inferior tibiofibular ligament and its contact with the talus is a normal finding that may become pathological due to anatomical variations or anterolateral instability. [105] (10.1007/s00167-006-0275-7)

See Also

References

[1] Long-term Prognosis After Successful Nonoperative Treatment of Osteochondral Lesions of the Talus: An Observational 14-Year Follow-up Study. Orthopaedic Journal of Sports Medicine. 2020. DOI: 10.1177/2325967120924183

[2] Comparison of chondral versus osteochondral lesions of the talus after arthroscopic microfracture. Knee Surgery, Sports Traumatology, Arthroscopy. 2014. DOI: 10.1007/s00167-014-3061-y

[3] One-year follow-up data from the German Cartilage Registry (KnorpelRegister DGOU) in the treatment of chondral and osteochondral defects of the talus. Archives of Orthopaedic and Trauma Surgery. 2020. DOI: 10.1007/s00402-020-03631-z

[4] Osteochondral lesion of the talus: still a problem?. EFORT Open Reviews. 2022. DOI: 10.1530/eor-22-0024

[5] Long-term results of microfracture in the treatment of talus osteochondral lesions. Knee Surgery, Sports Traumatology, Arthroscopy. 2016. DOI: 10.1007/s00167-016-3990-8

[6] Arthroscopic microfracture for osteochondral lesions of the talus. Knee Surgery, Sports Traumatology, Arthroscopy. 2009. DOI: 10.1007/s00167-009-0914-x

[7] Osteochondral Lesion of the Talus. The American Journal of Sports Medicine. 2009. DOI: 10.1177/0363546509335765

[8] Results of arthroscopic microfracture treatment for traumatic and non-traumatic osteochondral lesions of the talus: a retrospective cohort study. BMC Musculoskeletal Disorders. 2025. DOI: 10.1186/s12891-025-08949-6

[9] Cartilage Transplantation Techniques for Talar Cartilage Lesions. Journal of the American Academy of Orthopaedic Surgeons. 2009. DOI: 10.5435/00124635-200907000-00001

[10] Autologous Chondrocyte Implantation of the Ankle. The American Journal of Sports Medicine. 2014. DOI: 10.1177/0363546514540587

[11] Trauma-induced spontaneous union of a talar osteochondritis dissecans: case report. Journal of ISAKOS. 2023. DOI: 10.1016/j.jisako.2023.05.002

[13] Osteochondral Autologous Transplantation Is Superior to Repeat Arthroscopy for the Treatment of Osteochondral Lesions of the Talus After Failed Primary Arthroscopic Treatment. The American Journal of Sports Medicine. 2014. DOI: 10.1177/0363546514535186

[14] Osteochondral transplantation of autologous graft for the treatment of osteochondral lesions of talus: 5- to 7-year follow-up. Knee Surgery, Sports Traumatology, Arthroscopy. 2014. DOI: 10.1007/s00167-014-3389-3

[15] Surgical Treatment for Osteochondral Lesions of the Talus. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2021. DOI: 10.1016/j.arthro.2021.10.002

[16] Functional Outcomes After Arthroscopic Cell-Free Osteochondral Scaffold Surgery. Orthopaedic Journal of Sports Medicine. 2014. DOI: 10.1177/2325967114s00160

[18] Comment on “No superior treatment for primary osteochondral defects of the talus. Dahmen J, et al. KSSTA 2017 Jun 27 PMID:28656457”. Knee Surgery, Sports Traumatology, Arthroscopy. 2017. DOI: 10.1007/s00167-017-4700-x

[19] CT arthrography visualizes tissue growth of osteochondral defects of the talus after microfracture. Knee Surgery, Sports Traumatology, Arthroscopy. 2017. DOI: 10.1007/s00167-017-4610-y

[20] Incidence of Coexisting Talar and Tibial Osteochondral Lesions Correlates With Patient Age and Lesion Location. Orthopaedic Journal of Sports Medicine. 2018. DOI: 10.1177/2325967118790965

[21] Editorial Commentary: Concomitant Stabilization Is Recommended When Treating Osteochondral Lesions of the Talus in Patients With Chronic Lateral Ankle Instability. Arthroscopy. 2025. DOI: 10.1016/j.arthro.2025.02.005

[22] Osteochondral Lesions of the Tibial Plafond: A Systematic Review. Orthopaedic Journal of Sports Medicine. 2021. DOI: 10.1177/23259671211029208

[23] Osteochondral lesions of the talus. Knee Surgery, Sports Traumatology, Arthroscopy. 2019. DOI: 10.1007/s00167-019-05647-4

[24] Arthroscopic Debridement and Microfracture of Osteochondral Lesion of the Talar Head. Arthroscopy Techniques. 2019. DOI: 10.1016/j.eats.2019.05.006

[25] All‐Arthroscopic Autologous Matrix‐Induced Chondrogenesis for the Treatment of Osteochondral Lesions of the Talus. Arthroscopy Techniques. 2015. DOI: 10.1016/j.eats.2015.02.010

[26] Bony periosteum‐covered iliac crest plug transplantation for severe osteochondral lesions of the talus: a modified mosaicplasty procedure. Knee Surgery, Sports Traumatology, Arthroscopy. 2013. DOI: 10.1007/s00167-013-2604-y

[27] Autologous chondrocyte implantation for the treatment of chondral and osteochondral defects of the talus: a meta‐analysis of available evidence. Knee Surgery, Sports Traumatology, Arthroscopy. 2011. DOI: 10.1007/s00167-011-1729-0

[28] Arthroscopic debridement and bone marrow stimulation for talar osteochondral lesions: current concepts. Journal of ISAKOS. 2017. DOI: 10.1136/jisakos-2016-000099

[29] Campbell S Operative Orthopaedics 4 Volume Set. RECONSTRUCTION OF THE PATELLOFEMORAL AND PATELLOTIBIAL LIGAMENTS WITH A SEMITENDINOSUS TENDON GRAFT > EXCISION OF OSTEOCHONDRAL FRAGMENT OF THE TALUS.

[30] Campbell S Operative Orthopaedics 4 Volume Set. ARTHROSCOPIC EXAMINATION AND DEBRIDEMENT OF THE ANKLE JOINT > OSTEochondral Lesions of the Talus.

[31] Osteochondral Lesions of the Talar Dome. Journal of the American Academy of Orthopaedic Surgeons. 1996. DOI: 10.5435/00124635-199603000-00001

[32] Comparison of clinical outcomes between arthroscopic subchondral drilling and microfracture for osteochondral lesions of the talus. Knee Surgery, Sports Traumatology, Arthroscopy. 2015. DOI: 10.1007/s00167-015-3511-1

[36] Arthroscopic Management of Osteochondral Lesion of Plantar Medial Talar Head. Arthroscopy Techniques. 2019. DOI: 10.1016/j.eats.2018.09.001

[38] Talar OsteoPeriostic Grafting from the Iliac Crest (TOPIC). Journal of Bone and Joint Surgery. 2023. DOI: 10.2106/jbjs.22.01322

[41] Microfracture for chondral defects of the talus: maintenance of early results at midterm follow‐up. Knee Surgery, Sports Traumatology, Arthroscopy. 2010. DOI: 10.1007/s00167-009-1036-1

[42] Arthroscopic autologous chondrocyte implantation in the ankle joint. Knee Surgery, Sports Traumatology, Arthroscopy. 2013. DOI: 10.1007/s00167-013-2640-7

[44] Subchondral Bone Degradation After Microfracture for Osteochondral Lesions of the Talus: An MRI Analysis. The American Journal of Sports Medicine. 2017. DOI: 10.1177/0363546517739606

[45] Campbell S Operative Orthopaedics 4 Volume Set. REPAIR OF ACUTE RUPTURE OF LATERAL LIGAMENTS > Classification Systems for Osteochondral Lesions of the Talus > ARTHROSCOPY.

[46] Proposal of a new CT arthrographic classification system of osteochondral lesions of the talus. Orthopaedics & Traumatology: Surgery & Research. 2021. DOI: 10.1016/j.otsr.2021.102890

[49] Autologous Chondrocyte Implantation of the Ankle. The American Journal of Sports Medicine. 2008. DOI: 10.1177/0363546508325670

[50] New Perspectives of Osteochondral Lesion of the Talus. Orthopaedic Journal of Sports Medicine. 2019. DOI: 10.1177/2325967119s00453

[51] Arthroscopy for athletic foot and ankle injuries. Clinics in Sports Medicine. 2004. DOI: 10.1016/s0278-5919(03)00093-0

[52] Surgical treatment of transchondral talar-dome fractures (osteochondritis dissecans). Long-term follow-up.. The Journal of Bone & Joint Surgery. 1980. DOI: 10.2106/00004623-198062040-00020

[53] Treatment principles for osteochondral lesions in foot and ankle. International Orthopaedics. 2013. DOI: 10.1007/s00264-013-2076-1

[54] Paper 69: Do Patients Participate in Sports or Recreational Activity After Osteochondral Allograft Transplantation of the Talus?. Orthopaedic Journal of Sports Medicine. 2023. DOI: 10.1177/2325967123s00093

[57] Osteochondral defects in the ankle: why painful?. Knee Surgery, Sports Traumatology, Arthroscopy. 2010. DOI: 10.1007/s00167-010-1064-x

[58] Operative Treatment of Osteochondral Lesions of the Talus. Journal of Bone and Joint Surgery. 2013. DOI: 10.2106/jbjs.l.00773

[59] Poor osteochondral repair by a biomimetic collagen scaffold: 1‐ to 3‐year clinical and radiological follow‐up. Knee Surgery, Sports Traumatology, Arthroscopy. 2015. DOI: 10.1007/s00167-015-3538-3

[60] Three-dimensional talar shape seems not a factor in chronic mechanical ankle instability. BMC Musculoskeletal Disorders. 2026. DOI: 10.1186/s12891-025-09458-2

[61] Topographic Variations in Biomechanical and Biochemical Properties in the Ankle Joint: An In Vitro Bovine Study Evaluating Native and Engineered Cartilage. Arthroscopy. 2014. DOI: 10.1016/j.arthro.2014.05.025

[63] Treatment of post‐traumatic osteochondral lesions of the talus: a four‐step approach. Knee Surgery, Sports Traumatology, Arthroscopy. 2012. DOI: 10.1007/s00167-012-2028-0

[64] Single‐Stage All‐Arthroscopic Autologous Cancellous Bone Transplantation in Treatment of Cystic Osteochondral Lesion of the Talus. Arthroscopy Techniques. 2024. DOI: 10.1016/j.eats.2024.103208

[67] Autologous Matrix-Induced Chondrogenesis for Osteochondral Lesions of the Talus: A Clinical and Radiological 2- to 8-Year Follow-up Study. The American Journal of Sports Medicine. 2019. DOI: 10.1177/0363546519841574

[68] Arthroscopic treatment of osteochondral lesions of the talus.. The Journal of Bone & Joint Surgery. 1986. DOI: 10.2106/00004623-198668060-00007

[69] Medial approaches to osteochondral lesion of the talus without medial malleolar osteotomy. Knee Surgery, Sports Traumatology, Arthroscopy. 2009. DOI: 10.1007/s00167-009-1019-2

[71] Autologous Osteochondral Transplantation of the Talus Partially Restores Contact Mechanics of the Ankle Joint. The American Journal of Sports Medicine. 2011. DOI: 10.1177/0363546511419811

[72] Comparison of medial osteochondral lesions of the talus characteristics between chronic lateral ankle instability and ankle varus. Journal of Orthopaedic Surgery and Research. 2025. DOI: 10.1186/s13018-025-06232-x

[73] The Unloading Effect of Supramalleolar Versus Sliding Calcaneal Osteotomy for Treatment of Osteochondral Lesions of the Medial Talus: A Biomechanical Study. Orthopaedic Journal of Sports Medicine. 2023. DOI: 10.1177/23259671231176295

[74] Non‐operative management for osteochondral lesions of the talus: a systematic review of treatment modalities, clinical‐ and radiological outcomes. Knee Surgery, Sports Traumatology, Arthroscopy. 2023. DOI: 10.1007/s00167-023-07408-w

[82] Tachdjian S Pediatric Orthopaedics From The Texas Scottish Rite Hospital For Children E Book. Plate 35.2 Scapulocostal Stabilization for Scapular Winging (Ketenjian Technique) > Osteochondral Lesions of the Talus > Classification.

[88] Bilateral Talar Osteochondritis Dissecans with Lax Ankle Ligaments. The Journal of Bone & Joint Surgery. 1970. DOI: 10.2106/00004623-197052010-00018

[95] Osteochondral Transplantation of the Talus. The American Journal of Sports Medicine. 2011. DOI: 10.1177/0363546510397726

[96] Difference in orientation of the talar articular facets between healthy ankle joints and ankle joints with chronic instability. Journal of Orthopaedic Research. 2021. DOI: 10.1002/jor.25068

[101] The ankle cartilage cascade: incremental cartilage damage in the ankle joint. Knee Surgery, Sports Traumatology, Arthroscopy. 2021. DOI: 10.1007/s00167-021-06755-w

[105] The distal fascicle of the anterior inferior tibiofibular ligament as a cause of tibiotalar impingement syndrome: a current concepts review. Knee Surgery, Sports Traumatology, Arthroscopy. 2007. DOI: 10.1007/s00167-006-0275-7

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