Christiaan J.A. van Bergen

Osteochondral defects in the ankle: why painful?

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. The development of a symptomatic OD depends on various factors, including the damage and insufficient repair of the subchondral bone plate. The ankle joint has a high congruency. 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. This will result in local osteolysis and can explain the slow development of a subchondral cyst. The pain does not arise from the cartilage lesion, but is most probably caused by repetitive high fluid pressure during walking, which results in stimulation of the highly innervated subchondral bone underneath the cartilage defect. Understanding the natural history of osteochondral defects could lead to the development of strategies for preventing progressive joint damage.

Advancements in ankle arthroscopy.

Important progress has been made during the past 30 years in arthroscopic ankle surgery. Ankle arthroscopy has gradually changed from a diagnostic to a therapeutic tool. Most arthroscopic procedures can be performed by using the anterior working area with the ankle in dorsiflexion or plantar flexion; there is no need for routine ankle distraction. Anterior ankle problems, such as anterior impingement syndrome, are approached by anteromedial and anterolateral portals and, if necessary, an accessory portal. Most osteochondral defects can be reached from anterior with the ankle in plantar flexion. For a far posterior location, the osteochondral defect can be approached from posterior. The twoportal hindfoot endoscopic technique (ie, both arthroscopic and endoscopic surgery), with the patient in the prone position, provides excellent access to the posterior ankle compartment and to posteriorly located extra-articular structures.

Arthroscopic treatment of osteochondral defects of the talus: outcomes at eight to twenty years of follow-up.

BACKGROUND The primary aim of this study was to assess the long-term clinical and radiographic outcomes of arthroscopic debridement and bone marrow stimulation for talar osteochondral defects. The secondary aim was to identify prognostic factors that affect the long-term results. METHODS Fifty (88%) of fifty-seven eligible patients with a primary osteochondral defect treated with arthroscopic debridement and bone marrow stimulation were evaluated after a mean follow-up of twelve years (range, eight to twenty years). Clinical assessment included the Ogilvie-Harris score, Berndt and Harty outcome question, American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, and Short Form-36 (SF-36) as well as resumption of work and sports. Weight-bearing radiographs were compared with preoperative radiographs with use of an ankle osteoarthritis classification system. The size, location, and classification of the defect, patient age and body mass index, traumatic etiology, and duration of symptoms were recorded and analyzed with use of univariate logistic regression. RESULTS The Ogilvie-Harris score was excellent in 20% of patients, good in 58%, fair in 22%, and poor in 0%. According to the Berndt and Harty outcome question, 74% of patients rated the ankle as good, 20% as fair, and 6% as poor. The median AOFAS score was 88 (range, 64 to 100). Of the eight subscales of the SF-36, six were comparable with population norms and two were superior in the study group. Ninety-four percent of patients had resumed work and 88% had resumed sports. The radiographs indicated an osteoarthritis grade of 0 in 33% of the patients, I in 63%, II in 4%, and III in 0%. Compared with the preoperative osteoarthritis classification, 67% of radiographs showed no progression and 33% showed progression by one grade. None of the prognostic factors was significantly associated with the Ogilvie-Harris score or progression of osteoarthritis. CONCLUSIONS This study suggests that initial success of arthroscopic debridement and bone marrow stimulation for osteochondral defects of the talus are maintained over time. No factors that were predictive of the outcome could be identified.

Novel metallic implantation technique for osteochondral defects of the medial talar dome. A cadaver study.

Background and purpose A metallic inlay implant (HemiCAP) with 15 offset sizes has been developed for the treatment of localized osteochondral defects of the medial talar dome. The aim of this study was to test the following hypotheses: (1) a matching offset size is available for each talus, (2) the prosthetic device can be reproducibly implanted slightly recessed in relation to the talar cartilage level, and (3) with this implantation level, excessive contact pressures on the opposite tibial cartilage are avoided. Methods The prosthetic device was implanted in 11 intact fresh-frozen human cadaver ankles, aiming its surface 0.5 mm below cartilage level. The implantation level was measured at 4 margins of each implant. Intraarticular contact pressures were measured before and after implantation, with compressive forces of 1,000–2,000 N and the ankle joint in plantigrade position, 10˚ dorsiflexion, and 14˚ plantar flexion. Results There was a matching offset size available for each specimen. The mean implantation level was 0.45 (SD 0.18) mm below the cartilage surface. The defect area accounted for a median of 3% (0.02–18) of the total ankle contact pressure before implantation. This was reduced to 0.1% (0.02–13) after prosthetic implantation. Interpretation These results suggest that the implant can be applied clinically in a safe way, with appropriate offset sizes for various talar domes and without excessive pressure on the opposite cartilage.

Potential pitfall in the microfracturing technique during the arthroscopic treatment of an osteochondral lesion

Debridement and bone marrow stimulation of the subchondral bone is currently considered to be the primary surgical treatment of most osteochondral lesions of the talus. Different methods of bone marrow stimulation are used, including drilling, abrasion, and microfracturing. The latter has gained recent popularity. In this technical note we describe a potential pitfall in the microfracturing technique. The microfracture awl can easily create small bony particles on retrieval of the probe that may stay behind in the joint. It is emphasized that the joint should be carefully inspected and flushed at the end of each procedure, in order to prevent leaving behind any loose bony particles.

Computed Tomography of the Ankle in Full Plantar Flexion: A Reliable Method for Preoperative Planning of Arthroscopic Access to Osteochondral Defects of the Talus

PURPOSE The purpose of this study was to determine whether preoperative computed tomography (CT) of the ankle joint in full plantar flexion is a reliable and accurate tool to determine the anterior arthroscopic accessibility of talar osteochondral defects (OCDs). METHODS Twenty consecutive patients were prospectively studied. All patients had an OCD of the talar dome and had a preoperative CT scan of the affected ankle in maximum plantar flexion. Accessibility of the OCD was defined by the distance between the anterior border of the OCD and the anterior distal tibial rim. This distance was measured on sagittal CT reconstructions by 2 investigators. The reference standard was the distance between the same landmarks measured during anterior ankle arthroscopy by an orthopaedic surgeon blinded to the CT scans. Intraobserver and interobserver reliability of CT, as well as the correlation and agreement between CT and arthroscopy, were calculated. RESULTS The measured distance between the anterior border of the OCD and the anterior distal tibial rim ranged from -3.1 to 9.1 mm on CT and from -3.0 to 8.5 mm on arthroscopy. The intraobserver and interobserver reliability of the measurements made on CT scans (intraclass correlation coefficients >0.99, P < .001), as well as the correlation between CT and arthroscopy, were excellent (r = 0.98, P < .001). CONCLUSIONS Measurements on CT scans of the ankle in full plantar flexion are a reliable and accurate preoperative method to determine the in situ arthroscopic location of talar OCDs.

Pulsed electromagnetic fields after arthroscopic treatment for osteochondral defects of the talus: double-blind randomized controlled multicenter trial

BackgroundOsteochondral talar defects usually affect athletic patients. The primary surgical treatment consists of arthroscopic debridement and microfracturing. Although this is mostly successful, early sport resumption is difficult to achieve, and it can take up to one year to obtain clinical improvement. Pulsed electromagnetic fields (PEMFs) may be effective for talar defects after arthroscopic treatment by promoting tissue healing, suppressing inflammation, and relieving pain. We hypothesize that PEMF-treatment compared to sham-treatment after arthroscopy will lead to earlier resumption of sports, and aim at 25% increase in patients that resume sports.Methods/DesignA prospective, double-blind, randomized, placebo-controlled trial (RCT) will be conducted in five centers throughout the Netherlands and Belgium. 68 patients will be randomized to either active PEMF-treatment or sham-treatment for 60 days, four hours daily. They will be followed-up for one year. The combined primary outcome measures are (a) the percentage of patients that resume and maintain sports, and (b) the time to resumption of sports, defined by the Ankle Activity Score. Secondary outcome measures include resumption of work, subjective and objective scoring systems (American Orthopaedic Foot and Ankle Society – Ankle-Hindfoot Scale, Foot Ankle Outcome Score, Numeric Rating Scales of pain and satisfaction, EuroQol-5D), and computed tomography. Time to resumption of sports will be analyzed using Kaplan-Meier curves and log-rank tests.DiscussionThis trial will provide level-1 evidence on the effectiveness of PEMFs in the management of osteochondral ankle lesions after arthroscopy.Trial registrationNetherlands Trial Register (NTR1636)

Arthroscopic Accessibility of the Talus Quantified by Computed Tomography Simulation

Background: Anterior ankle arthroscopy is the preferred surgical approach for the treatment of osteochondral defects of the talus (OCDs). However, the ankle is a congruent joint with limited surgical access. Purpose: The dual purpose of this study was (1) to quantify the anterior arthroscopic reach (defined as the proportion of the talar dome articular surface located anterior to the anterior distal tibial rim) with the ankle in full plantar flexion and (2) to identify predictive factors of the arthroscopic reach. Study Design: Descriptive laboratory study. Methods: Computed tomography scans were obtained of 59 ankles (57 patients aged 33 ± 11 years) in full plantar flexion in a nonmetallic 3-dimensional footplate. The arthroscopic reach of both the medial and lateral talar domes was assessed on sagittal reconstructions using a custom-made software routine. Intraobserver and interobserver reliability were calculated by intraclass correlation coefficients (ICCs). Various predictive factors of the arthroscopic reach were analyzed by multivariate linear regression analysis. Results: The arthroscopic reach was 48.2% ± 6.7% (range, 26.7%-60.7%) of the medial talar dome and 47.8% ± 6.5% (range, 31.2%-65.1%) of the lateral talar dome (P = .62). The intraobserver and interobserver reliability of both measurements were excellent (ICC, .99). The clinical plantarflexion angle was a statistically significant predictive factor of both the medial and lateral arthroscopic reaches (ie, increased plantar flexion corresponded to increased area of access), while joint laxity, gender, and age were not predictive. Conclusion: Almost half of the talar dome is accessible anterior to the anterior distal tibial rim. The plantarflexion angle is an independent predictive factor of the arthroscopic reach both medially and laterally. Clinical Relevance: These results may facilitate preoperative planning of the surgical approach for OCDs.

Effects of Pulsed Electromagnetic Fields on Return to Sports after Arthroscopic Debridement and Microfracture of Osteochondral Talar Defects: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial

Background: Osteochondral defects (OCDs) of the talus usually affect athletic patients. The primary surgical treatment consists of arthroscopic debridement and microfracture. Various possibilities have been suggested to improve the recovery process after debridement and microfracture. A potential solution to obtain this goal is the application of pulsed electromagnetic fields (PEMFs), which stimulate the repair process of bone and cartilage. Hypothesis: The use of PEMFs after arthroscopic debridement and microfracture of an OCD of the talus leads to earlier resumption of sports and an increased number of patients that resume sports. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 68 patients were randomized to receive either PEMFs (n = 36) or placebo (n = 32) after arthroscopic treatment of an OCD of the talus. The primary outcomes (ie, the number of patients who resumed sports and time to resumption of sports) were analyzed with Kaplan-Meier curves as well as Mann-Whitney U, chi-square, and log-rank tests. Secondary functional outcomes were assessed with questionnaires (American Orthopaedic Foot and Ankle Society ankle-hindfoot score, Foot and Ankle Outcome Score, EuroQol, and numeric rating scales for pain and satisfaction) at multiple time points up to 1-year follow-up. To assess bone repair, computed tomography scans were obtained at 2 weeks and 1 year postoperatively. Results: Almost all outcome measures improved significantly in both groups. The percentage of sport resumption (PEMF, 79%; placebo, 80%; P = .95) and median time to sport resumption (PEMF, 17 weeks; placebo, 16 weeks; P = .69) did not differ significantly between the treatment groups. Likewise, there were no significant between-group differences with regard to the secondary functional outcomes and the computed tomography results. Conclusion: PEMF does not lead to a higher percentage of patients who resume sports or to earlier resumption of sports after arthroscopic debridement and microfracture of talar OCDs. Furthermore, no differences were found in bone repair between groups. Registration: Netherlands Trial Register NTR1636.

Diagnosing, planning and evaluating osteochondral ankle defects with imaging modalities

This current concepts review outlines the role of different imaging modalities in the diagnosis, preoperative planning, and follow-up of osteochondral ankle defects. An osteochondral ankle defect involves the articular cartilage and subchondral bone (usually of the talus) and is mostly caused by an ankle supination trauma. Conventional radiographs are useful as an initial imaging tool in the diagnostic process, but have only moderate sensitivity for the detection of osteochondral defects. Computed tomography (CT) and magnetic resonance imaging (MRI) are more accurate imaging modalities. Recently, ultrasonography and single photon emission CT have been described for the evaluation of osteochondral talar defects. CT is the most valuable modality for assessing the exact location and size of bony lesions. Cartilage and subchondral bone damage can be visualized using MRI, but the defect size tends to be overestimated due to bone edema. CT with the ankle in full plantar flexion has been shown a reliable tool for preoperative planning of the surgical approach. Postoperative imaging is useful for objective assessment of repair tissue or degenerative changes of the ankle joint. Plain radiography, CT and MRI have been used in outcome studies, and different scoring systems are available.