The Subchondral Bone Is Affected by Bone Marrow Stimulation: A Systematic Review of Preclinical Animal Studies

Subchondral bone: An emerging target for the treatment of articular surface lesions of the knee

Purpose

When dealing with the health status of the knee articular surface, the entire osteochondral unit has gained increasing attention, and in particular the subchondral bone, which plays a key role in the integrity of the osteochondral unit. The aim of this article was to discuss the current evidence on the role of the subchondral bone.

Methods

Experts from different geographical regions were involved in performing a review on highly discussed topics about the subchondral bone, ranging from its etiopathogenetic role in joint degeneration processes to its prognostic role in chondral and osteochondral defects, up to treatment strategies to address both the subchondral bone and the articular surface.

Discussion

Subchondral bone has a central role both from an aetiologic point of view and as a diagnostic tool, and its status was found to be relevant also as a prognostic factor in the follow-up of chondral treatment. Finally, the recognition of its importance in the natural history of these lesions led to consider subchondral bone as a treatment target, with the development of osteochondral scaffolds and procedures to specifically address osteochondral lesions.

Conclusion

Subchondral bone plays a central role in articular surface lesions from different points of view. Several aspects still need to be understood, but a growing interest in subchondral bone is to be expected in the upcoming future towards the optimization of joint preservation strategies.

Level of Evidence

Level V, expert opinion.

Outcomes Following the Use of Extracellular Matrix Cartilage Allograft for the Management of Osteochondral Lesions of the Talus: A Systematic Review

Extracellular matrix cartilage allograft (EMCA) is a novel biological strategy utilized to augment the repair of osteochondral lesions of the talus (OLTs). However, there is no consensus on the precise role and outcomes following its use in the treatment of OLTs. The purpose of this systematic review was to evaluate the clinical and radiological outcomes following the use of EMCA for the treatment of OLT. During July 2023, the PubMed, Embase, and Cochrane Library databases were systematically reviewed to identify clinical studies examining outcomes following EMCA for the management of OLTs. In total, 162 patients (162 ankles) across five studies received EMCA as part of their surgical procedure at a weighted mean follow-up time of 23.8±4.2 months. Across all five studies, there were improvements in subjective clinical outcomes following the use of EMCA, regardless of the clinical scoring tool utilized. Two studies demonstrated superior postoperative magnetic resonance observation of cartilage repair tissue (MOCART) scores in the EMCA cohort compared to the bone marrow stimulation (BMS) cohort alone. In the EMCA-BMS cohort, there were seven complications (9%) and three failures (4.1%). In the autologous osteochondral transplantation (AOT) cohort, there were 10 complications (38.5%), zero failures, and six secondary surgical procedures (23.1%). In the EMCA alone cohort, there were zero complications and three failures (4.3%), all of which underwent an unspecified revision procedure. This current systematic review demonstrated improvements in both clinical and radiological outcomes following the use of EMCA for the treatment of OLTs. Further prospective comparative studies with longer follow-up times are warranted to determine the precise role of EMCA in the management of OLT.

Evidence-Based Update on the Surgical Technique and Clinical Outcomes of Retrograde Drilling: A Systematic Review

BACKGROUND

Retrograde drilling is an established surgical technique to treat osteochondral lesions of the talus (OLT). It involves non-trans-articular drilling to induce subchondral bone revascularization and bone formation without damaging the overlying articular cartilage. The present study aimed to elucidate the heterogeneity of clinical studies on retrograde drilling for OLT.

DESIGN

A systematic search of the MEDLINE, Web of Science, EMBASE, and Cochrane Library databases for studies published between January 1996 and August 27, 2022, was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines by two independent reviewers. The included studies were evaluated for their level of evidence (LoE) and quality of evidence (QoE) using the Modified Coleman Methodology Score. Variables reporting surgical and clinical outcomes and complications were evaluated.

RESULTS

Eleven studies with 207 ankles were included (mean follow-up period = 31.1 months). The mean LoE was 3.8 (LoE 3: two studies, LoE 4: nine studies), and the mean QoE was 50.8 (fair: three studies, poor: eight studies). Ten studies used the American Orthopedic Foot and Ankle Society (AOFAS) score, which improved from 57.9 preoperatively to 86.1 postoperatively. The period and protocol of conservative treatment, lesion character, surgical technique, and postoperative protocol were inconsistent or underreported.

CONCLUSIONS

This systematic review revealed that low LoE and poor QoE, coupled with heterogeneity among the included studies, impede definitive conclusions regarding the effectiveness of this technique. Consequently, well-designed clinical trials are essential to develop standardized clinical guidelines for using retrograde drilling in OLT.

Particulated juvenile cartilage allograft for the treatment of osteochondral lesions of the talus is associated with a high complication rate and a high failure rate at short-term follow-up: A systematic review

PURPOSE

The purpose of this systematic review was to evaluate the clinical and radiological outcomes together with the complication rates and failure rates at short-term follow-up following particulated juvenile cartilage allograft (PJCA) for the management of osteochondral lesions of the talus (OLT).

METHODS

During October 2023, the PubMed, Embase and Cochrane library databases were systematically reviewed to identify clinical studies examining outcomes following PJCA for the management of OLTs. Data regarding study characteristics, patient demographics, lesion characteristics, subjective clinical outcomes, radiological outcomes, complications and failures were extracted and analysed.

RESULTS

Twelve studies were included. In total, 241 patients underwent PJCA for the treatment of OLT at a weighted mean follow-up of 29.0 ± 24.9 months. The weighted mean lesion size was 138.3 ± 59.6 mm2 . Prior surgical intervention was recorded in seven studies, the most common of which was microfracture (65.9%). The weighted mean American Orthopaedic Foot and Ankle Society score improved from a preoperative score of 58.5 ± 3.2 to a postoperative score of 83.9 ± 5.3. The weighted mean postoperative magnetic resonance observation of cartilage repair tissue (MOCART) score was 48.2 ± 3.3. The complication rate was 25.2%, the most common of which was allograft hypertrophy (13.2%). Thirty failures (12.4%) were observed at a weighted mean time of 9.8 ± 9.6 months following the index procedure.

CONCLUSION

This systematic review demonstrated a moderate improvement in subjective clinical outcomes following PJCA for the treatment of OLT at short term follow-up. However, postoperative MOCART scores were reported as poor. In addition, a high complication rate (25.2%) and a high failure rate (12.4%) at short-term follow-up was observed, calling into question the efficacy of PJCA for the treatment of large OLTs. In light of the available evidence, PJCA for the treatment of large OLTs cannot be currently recommended.

LEVEL OF EVIDENCE

Level IV.

Bone Marrow Stimulation for Arthroscopic Rotator Cuff Repair: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Bone marrow stimulation (BMS) has been proposed to augment healing at the time of arthroscopic rotator cuff repair (ARCR) by creating several bone marrow vents in the footprint of the rotator cuff, allowing mesenchymal stem cells, platelets, and growth factors to cover the area as a "crimson duvet."

PURPOSE

To perform a meta-analysis of randomized controlled trials (RCTs) to compare the outcomes after BMS and a control for those undergoing ARCR.

STUDY DESIGN

Meta-analysis; Level of evidence, 1.

METHODS

A literature search of 3 databases was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RCTs comparing BMS and a control for ARCR were included. Clinical outcomes were compared, and a P value <.05 was considered to be statistically significant.

RESULTS

A total of 7 RCTs with 576 patients were included. Overall, 18.8% of patients treated with BMS and 21.0% of patients treated with a control had a retear (I2 = 43%; P = .61). With BMS, the mean Constant score was 88.2, and with the control, the mean Constant score was 86.7 (P = .12). Additionally, there was no significant difference in the American Shoulder and Elbow Surgeons score (94.3 vs 93.2, respectively; P = .31) or visual analog scale score (0.9 vs 0.9, respectively; P = .89).

CONCLUSION

The level 1 evidence in the literature did not support BMS as a modality to improve retear rates or clinical outcomes after ARCR.

Second-Look Arthroscopy Shows Inferior Cartilage after Bone Marrow Stimulation Compared with Other Operative Techniques for Osteochondral Lesions of the Talus: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare cartilage quality after different surgical interventions for osteochondral lesions of the talus (OLT), evaluated by second-look arthroscopy. Secondary aims were to report concomitant diagnoses, and to correlate cartilage quality with clinical and radiological outcomes. This review hypothesizes that the cartilage repair after bone marrow stimulation (BMS) is inferior to the other available treatment options.

METHODS

PROSPERO ID: CRD42022311489. Studies were retrieved through PubMed, EMBASE (Ovid), and Cochrane Library. Studies were included if they reported cartilage quality after second-look investigation after surgical treatment of OLT. The primary outcome measure was the cartilage quality success and failure rates (%) per surgical intervention group. Correlations between the cartilage quality and clinical or radiological outcomes were calculated.

RESULTS

Twenty-nine studies were included, comprising 586 ankles that had undergone second-look arthroscopy on average 16 months after initial surgery. The success rate for BMS was 57% (95% confidence interval [CI] = 48%-65%), for fixation (FIX) 86% (95% CI = 70%-94%), for osteo(chondral) transplantation (OCT) 91% (95% CI = 80%-96%), for cartilage implementation techniques (CITs) 80% (95% CI = 69%-88%), and for retrograde drilling 100% (95% CI = 66%-100%). The success rate of BMS was significantly lower than FIX, OCT, and CIT (P < 0.01). There were no significant differences between other treatment groups. A moderate positive significant correlation between the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score and the International Cartilage Repair Society score (ICRS) was found (ρ = 0.51, P < 0.001).

CONCLUSIONS

Successful restoration of cartilage quality was found in the majority of surgically treated OLTs. However, BMS yields inferior cartilage quality compared with FIX, OCT, and CIT. Study Design. Systematic review and meta-analysis. Level of evidence. Level IV, systematic review and meta-analysis.

Microdrilling Resulted in Less Subchondral Bone Destruction Than a Traditional Microfracture Awl for Articular Cartilage Defect Bone Marrow Stimulation

Purpose

The purpose of this study was to compare bone marrow stimulation using micro-computed tomography (micro-CT) analysis of an abrasion arthroplasty technique, drilling k-wire technique, traditional microfacture awl, or a microdrill instrument for subchondral bone defects.

Methods

Eleven cadaveric distal femoral specimens were obtained and divided into 3 common areas of osteochondral defect: trochlea and weightbearing portions of the medial and lateral femoral condyles. Each area of interest was then denuded of cartilage using a PoweRasp and divided into quadrants. Each quadrant was assigned either a 1.6 mm Kirschner wire (k-wire), 1.25 mm microfracture awl, 1.5 mm fluted microdrill, PowerPick, or a curette (abrasion arthroplasty) to create 4 channels into the subchondral bone sing the same instrument. Subchondral bone and adjacent tissue areas were then evaluated using micro-CT to analyze adjacent bone destruction and extension into the bone marrow.

Results

Overall, there was a significantly decreased area of bone destruction or compression using the microdrill (0.030 mm) as compared to the microfracture awl (0.072 mm) and k-wire (0.062 mm) (P < .05). Within the trochlea and the medial femoral condyle, there was significantly decreased bony compression with the microdrill as compared to the awl and k-wire (P < .05); however, when stratified, this was not significant among the lateral femoral condylar samples (P = .08).

Conclusion

Bone marrow stimulation causes bony compression that may negatively impact subchondral bone and trabecular alignment. It is important to understand which tools used for bone marrow stimulation cause the least amount of damage to the subchondral bone.

Clinical Relevance

This study demonstrates the decreased subchondral bony defects seen with the microdrill versus the traditional microfracture awl indicating that when performing bone marrow stimulation, the microdrill may be a less harmful tool to the subchondral bone.

Advances in Cartilage Repair

Osteochondral lesions of the ankle joint are typically associated with a traumatic etiology and present with ankle pain and swelling. Conservative management yields unsatisfactory results because of the poor healing capacity of the articular cartilage. Smaller lesions (<100 mm² or <10 mm) can be treated with less invasive procedures such as arthroscopic debridement, anterograde drilling, scaffold-based therapies, and augmentation with biological adjuvants. For patients with large lesions (>100 mm² or >10 mm), cystic lesions, uncontained lesions, or patients who have failed prior bone marrow stimulation, management with autologous osteochondral transplantation is indicated.

Prognostic Factors for the Clinical Outcome after Microfracture Treatment of Chondral and Osteochondral Defects in the Knee Joint: A Systematic Review

OBJECTIVE

The objective of this study is to establish which patient and lesion characteristics are related to the clinical outcome after microfracture of cartilage defects in the knee.

STUDY DESIGN

Systematic review.

METHODS

After preregistration, PubMed, Embase, and Cochrane were searched for studies that analyzed prognostic factors for the outcome of microfracture treatment in the knee. The criteria for inclusion were outcome measured using Patient-Reported Outcome Measures (PROMs), a clinical study with ≥10 participants receiving microfracture, and a minimal follow-up period of 1 year.

RESULTS

For none of the investigated prognostic factors, effect size reporting was sufficiently homogeneous to conduct a meta-analysis. However, a majority of the included studies identified higher age, larger lesion size, longer preoperative symptom duration, and previous surgery on the ipsilateral knee, especially meniscectomy and anterior cruciate ligament reconstruction, as factors that are reported to be correlated to a less favorable outcome. A lesion location that does not include the trochlea or the patellofemoral joint and is not weightbearing, a nondegenerative mechanism of injury, and a single lesion were reported as factors that predict a favorable outcome. As to gender, body mass index, preoperative activity level, smoking, and concomitant knee surgery, the included articles were inconclusive or no effect was reported.

CONCLUSIONS

Several factors correlated with the clinical result after microfracture treatment. However, the information on the effect sizes of the influence on clinical outcome is incomplete due to poor reporting. Large-scale registries or pooling of homogeneous, well-reported data is needed to work toward prognostic models. That would be an important step toward personalized treatment.

Drug/bioactive eluting chitosan composite foams for osteochondral tissue engineering

Joint defects associated with a variety of etiologies often extend deep into the subchondral bone leading to functional impairment and joint immobility, and it is a very challenging task to regenerate the bone-cartilage interface offering significant opportunities for biomaterial-based interventions to improve the quality of life of patients. Herein drug-/bioactive-loaded porous tissue scaffolds incorporating nano-hydroxyapatite (nHAp), chitosan (CS) and either hydroxypropyl methylcellulose (HPMC) or Bombyx mori silk fibroin (SF) are fabricated through freeze drying method as subchondral bone substitute. A combination of spectroscopy and microscopy (Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), and X-ray fluorescence (XRF) were used to analyze the structure of the porous biomaterials. The compressive mechanical properties of these scaffolds are biomimetic of cancellous bone tissues and capable of releasing drugs/bioactives (exemplified with triamcinolone acetonide, TA, or transforming growth factor-β1, TGF-β1, respectively) over a period of days. Mouse preosteoblast MC3T3-E1 cells were observed to adhere and proliferate on the tissue scaffolds as confirmed by the cell attachment, live-dead assay and alamarBlue™ assay. Interestingly, RT-qPCR analysis showed that the TA downregulated inflammatory biomarkers and upregulated the bone-specific biomarkers, suggesting such tissue scaffolds have long-term potential for clinical application.

Limited evidence of adjuvant biologics with bone marrow stimulation for the treatment of osteochondral lesion of the talus: a systematic review

PURPOSE

To evaluate the complication rates, continuous functional outcome scores, and return to play data following bone marrow stimulation (BMS) versus biologics ± BMS for the treatment of osteochondral lesion of the talus (OLT).

METHODS

A systematic review was performed. The PubMed and Embase databases were searched using specific search terms and eligibility criteria according to the PRISMA guidelines. The level of evidence was assessed using published criteria by The Journal of Bone & Joint Surgery, and the quality of evidence using the Modified Coleman Methodology Score. Continuous variables were presented as mean ± standard deviation and categorical variables as frequencies (percentages).

RESULTS

BMS versus BMS + hyaluronic acid (HA): no complications in either treatment arm were reported. The mean American Orthopaedic Foot and Ankle Society score was 43.5 to 67.3 points and 44.0 to 72.4 points, respectively. The mean 10 mm Visual Analogue Scale pain score was 7.7 to 3.8 points and 7.5 to 2.5 points, respectively. BMS versus BMS + concentrated bone marrow aspirate (CBMA): the pooled overall complication rate was 17/64 (26.6%) versus 11/71 (15.5%), respectively (non-significant). The pool revision rate was 15/64 (23.4%) versus 6/71 (8.5%), respectively (p = 0.016). There has been a notable poor reporting of complication rates for the use of ADSC and PRP as adjuvant biological therapies to BMS for the treatment of OLT.

CONCLUSION

There was an overall limited comparative clinical evidence of adjuvant biologics with BMS versus BMS alone for the treatment of OLT. BMS + HA and BMS + CBMA can provide superior outcomes, albeit the currently limited evidence. Further studies are warranted to establish the true clinical superiority of the various biologics ± BMS versus BMS alone. These studies must also compare the various biologics against one another to determine, if any, the optimal biologic for OLT. Clinicians should counsel patients accordingly on these findings as required.

LEVEL OF EVIDENCE

Level III.

The effect of talus osteochondral defects of different area size on ankle joint stability: a finite element analysis

BACKGROUND

Osteochondral lesion of the talus (OLT) is one of the most common ankle injuries, which will lead to biomechanical changes in the ankle joint and ultimately affect ankle function. Finite element analysis (FEA) is used to clarify the effect of talus osteochondral defects on the stability of the ankle joint at different depths. However, no research has been conducted on talus osteochondral defect areas that require prompt intervention. In this research, FEA was used to simulate the effect of the area size of talus osteochondral defect on the stress and stability of the ankle joint under a specific depth defect.

METHODS

Different area sizes (normal, 2 mm* 2 mm, 4 mm* 4 mm, 6 mm* 6 mm, 8 mm* 8 mm, 10 mm* 10 mm, and 12 mm* 12 mm) of the three-dimensional finite element model of osteochondral defects were established. The model was used to simulate and calculate joint stress and displacement of the articular surface of the distal tibia and the proximal talus when the ankle joint was in the heel-strike, midstance, and push-off phases.

RESULTS

When OLT occurred, the contact pressure of the articular surface, the equivalent stress of the proximal talus, the tibial cartilage, and the talus cartilage did not change significantly with an increase in the size of the osteochondral defect area when the heel-strike phase was below 6 mm * 6 mm. Gradual increases started at 6 mm * 6 mm in the midstance and push-off phases. Maximum changes were reached when the defect area size was 12 mm * 12 mm. The same patterns were observed in the talus displacement.

CONCLUSIONS

The effect of the defect area of the ankle talus cartilage on the ankle biomechanics is evident in the midstance and push-off phases. When the size of the defect reaches 6 mm * 6 mm, the most apparent change in the stability of the ankle joint occurs, and the effect does not increase linearly with the increase in the size of the defect.

Arthroscopic debridement of osteochondral lesions of the talus: A systematic review

BACKGROUND

Arthroscopic debridement (AD) for the osteochondral lesions of the talar dome (OLT) was widely documented in the nineties with satisfactory results. However, in modern treatment algorithms, its role is not described. The present systematic review aims to evaluate the current evidence on the clinical outcomes of AD in the management of OLT.

METHODS

Two independent reviewers searched PubMed, EMBASE, Scopus, and Virtual Health Library databases evaluating the clinical outcomes of AD of OLT with a minimum 6-month follow-up. The following terms "talus", "chondral", "cartilage", "injury", "lesion", "delamination", "damage", "excision", "curettage", "debridement", "chondrectomy", "chondroplasty", were used alone and in combination with Boolean operators AND and OR. Studies in which surgical technique was not described, an additional procedure was performed after debridement, and/or outcomes were not reported separately when more than one technique was implemented were excluded. The modified Coleman methodology score (mCMS) was used to evaluate the methodological quality of the included studies. A narrative analysis was conducted. Publication bias was assessed using the ROBIS tool.

RESULTS

AD showed satisfactory short and medium-term outcomes for the primary treatment of OLT irrespectively of size and depth. However, the heterogeneity of the included studies and the level of available evidence hinders its recommendation.

CONCLUSIONS

There is a paucity of evidence evaluating AD alone for OLT treatment in the last two decades. Bone-marrow stimulation techniques remain the first-line surgical strategy for OLT treatment without proven superiority. Adopting AD for OLT treatment instead of MF could represent a paradigm breakthrough in clinical practice given its many potential advantages while preserving the subchondral plate.

The Effect of Single vs Serial Platelet-Rich Plasma Injections in Osteochondral Lesions Treated With Microfracture: An In Vivo Rabbit Model

BACKGROUND

Biological adjuvants are used after a musculoskeletal injury to improve healing, decrease inflammation, and restore joint homeostasis. Work on 1 such adjuvant, platelet-rich plasma (PRP), has suggested a positive effect when introduced during cartilage repair. However, it remains unknown whether healing osteochondral injuries benefit from serial PRP injections.

PURPOSE

To evaluate the effects of serial PRP injections versus a single PRP injection on reparative cartilaginous tissue, subchondral bone remodeling, and the expression of inflammatory cytokines in joint synovium.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 48 New Zealand White rabbits were randomly assigned to receive 1 (1P), 2 (2P), or 3 (3P) PRP injections. Cylindrical full-thickness cartilage defects (2.9 × 2.9 mm) with microdrillings (0.6-mm diameter) were created on the medial condyles of both knees. PRP was injected into the right knee after closure (groups 1P, 2P, and 3P), at 2 weeks after surgery (groups 2P and 3P), and at 4 weeks after surgery (group 3P). The left knees did not receive any PRP injections. A total of 6 rabbits in each group were euthanized at 3, 6, and 12 weeks postoperatively. Cartilage repair tissue was assessed using the Goebel macroscopic and modified International Cartilage Regeneration & Joint Preservation Society (ICRS) histological scoring systems. Subchondral bone remodeling was evaluated by micro-computed tomography analysis (micro-CT). Inflammatory cytokine levels were assessed by quantitative polymerase chain reaction.

RESULTS

No significant differences were found for the mean macroscopic score between the PRP groups at 12 weeks (control, 6.1 ± 3.3; group 1P, 3.4 ± 2.7; group 2P, 4.2 ± 2.9; group 3P, 0.7 ± 1.5). All PRP groups had a significantly higher mean modified ICRS histological score compared with the control group, but no significant difference was found among the PRP groups. No significant differences were seen in outcomes for the tested micro-CT parameters or cytokine expression levels.

CONCLUSION

Serial PRP injections conferred no apparent advantage over single injections according to evaluations of the macroscopic and histological appearance of the cartilaginous tissue, subchondral bone healing, and inflammatory cytokine expression levels in the synovium.

CLINICAL RELEVANCE

The use of PRP as a biological adjuvant to bone marrow stimulation for osteochondral lesions has the potential to enhance the quality of regenerative cartilaginous tissue. We recommend only a single PRP injection if the use of PRP is indicated by the operating surgeon as an adjuvant therapy for osteochondral lesions.

Osteochondral Lesions of the Talus: A Review on Talus Osteochondral Injuries, Including Osteochondritis Dissecans

This is a review on talus osteochondritis dissecans and talus osteochondral lesions. A majority of the osteochondral lesions are associated with trauma while the cause of pure osteochondritis dissecans is still much discussed with a possible cause being repetitive microtraumas associated with vascular disturbances causing subchondral bone necrosis and disability. Symptomatic nondisplaced osteochondral lesions can often be treated conservatively in children and adolescents while such treatment is less successful in adults. Surgical treatment is indicated when there is an unstable cartilage fragment. There are a large number of different operative technique options with no number one technique to be recommended. Most techniques have been presented in level II to IV studies with a low number of patients with short follow ups and few randomized comparisons exist. The actual situation in treating osteochondral lesions in the ankle is presented and discussed.

Evidence-based Treatment of Failed Primary Osteochondral Lesions of the Talus: A Systematic Review on Clinical Outcomes of Bone Marrow Stimulation

OBJECTIVE

The purpose of this study is to systematically review the literature and to evaluate the outcomes following bone marrow stimulation (BMS) for nonprimary osteochondral lesions of the talus (OLT).

DESIGN

A literature search was performed to identify studies published using PubMed (MEDLINE), EMBASE, CDSR, DARE, and CENTRAL. The review was performed according to the PRISMA guidelines. Two authors separately and independently screened the search results and conducted the quality assessment using the Methodological Index for Non-Randomized Studies (MINORS). Studies were pooled on clinical, sports, work, and imaging outcomes, as well as revision rates and complications. The primary outcome was clinical success rate.

RESULTS

Five studies with 70 patients were included in whom nonprimary OLTs were treated with secondary BMS. The pooled clinical success rate was 61% (95% confidence interval [CI], 50-72). The rate of return to any level of sport was 83% (95% CI, 70-91), while the return to pre-injury level of sport was 55% (95% CI, 34-74). The rate of return to work was 92% (95% CI, 78-97), and the complication rate was assessed to be 10% (95% CI, 4-22). Imaging outcomes were heterogeneous in outcome assessment, though a depressed subchondral bone plate was observed in 91% of the patients. The revision rate was 27% (95% CI, 18-40).

CONCLUSIONS

The overall success rate of arthroscopic BMS for nonprimary osteochondral lesions of the talus was 61%, including a revision rate of 27%. Return to sports, work, and complication outcomes yielded fair to good results.

Histological and Inflammatory Cytokine Analysis of Osteochondral Lesions of the Talus After Failed Microfracture: Comparison With Fresh Allograft Controls

Background:

The most common first-line treatment of osteochondral lesions of the talus (OLTs) is microfracture. Although many patients do well with this procedure, a number fail and require reoperation. The mechanism of failure of microfracture is unknown, and to our knowledge there has been no research characterizing failed microfracture regarding histological and inflammatory makeup of these lesions that may contribute to failure.

Purpose:

To characterize the structural and biochemical makeup of failed microfracture lesions.

Study Design:

Case series; Level of evidence, 4.

Methods:

Specimens from 8 consecutive patients with symptomatic OLTs after microfracture who later underwent fresh osteochondral allograft transplantation were analyzed. For each patient, the failed microfracture specimen and a portion of the fresh allograft replacement tissue were collected. The allograft served as a control. Histology of the failed microfracture and the allograft replacement was scored using the Osteoarthritis Research Society International (OARSI) system. Surface roughness was also compared. In addition, tissue culture supernatants were analyzed for 16 secreted cytokines and matrix metalloproteinases (MMPs) responsible for inflammation, pain, cartilage damage, and chondrocyte death.

Results:

The OARSI grade, stage, and total score as well as surface smoothness were significantly worse in the failed microfracture sample, indicating better cartilage and bone morphology for the allografts compared with the failed microfracture lesions. Analyzed cytokines and MMPs were significantly elevated in the microfracture tissue culture supernatants when compared with fresh osteochondral tissue supernatants.

Conclusion:

These data demonstrate a significantly rougher cartilage surface, cartilage and subchondral bone histology that more closely resembles osteoarthritis, and elevated inflammatory cytokines and MMPs responsible for pain, inflammation, cartilage damage, and chondrocyte death when compared with fresh osteochondral allografts used as controls.

A Systematic Review of Focal Cartilage Defect Treatments in Middle-Aged Versus Younger Patients

Background:

Focal cartilage defects are often debilitating, possess limited potential for regeneration, are associated with increased risk of osteoarthritis, and are predictive for total knee arthroplasty. Cartilage repair studies typically focus on the outcome in younger patients, but a high proportion of treated patients are 40 to 60 years of age (ie, middle-aged). The reality of current clinical practice is that the ideal patient for cartilage repair is not the typical patient. Specific attention to cartilage repair outcomes in middle-aged patients is warranted.

Purpose:

To systematically review available literature on knee cartilage repair in middle-aged patients and include studies comparing results across different age groups.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search was performed in EMBASE, MEDLINE, and the Cochrane Library database. Articles were screened for relevance and appraised for quality.

Results:

A total of 21 articles (mean Coleman Methodology Score, 64 points) were included. Two out of 3 bone marrow stimulation (BMS) studies, including 1 using the microfracture technique, revealed inferior clinical outcomes in middle-aged patients in comparison with younger patients. Nine cell-based studies were included showing inconsistent comparisons of results across age groups for autologous chondrocyte implantation (ACI). Bone marrow aspirate concentrate showed age-independent results at up to 8 years of follow-up. A negative effect of middle age was reported in 1 study for both ACI and BMS. Four out of 5 studies on bone-based resurfacing therapies (allografting and focal knee resurfacing implants [FKRIs]) showed age-independent results up to 5 years. One study in only middle-aged patients reported better clinical outcomes for FKRIs when compared with biological repairs.

Conclusion:

Included studies were heterogeneous and had low methodological quality. BMS in middle-aged patients seems to only result in short-term improvements. More research is warranted to elucidate the ameliorating effects of cell-based therapies on the aging joint homeostasis. Bone-based therapies seem to be relatively insensitive to aging and may potentially result in effective joint preservation. Age subanalyses in cohort studies, randomized clinical trials, and international registries should generate more evidence for the large but underrepresented (in terms of cartilage repair) middle-aged population in the literature.

Use of Extracellular Matrix Cartilage Allograft May Improve Infill of the Defects in Bone Marrow Stimulation for Osteochondral Lesions of the Talus

PURPOSE

To evaluate the effectiveness of extracellular matrix cartilage allograft (EMCA) as an adjuvant to bone marrow stimulation (BMS) compared with BMS alone in the treatment of osteochondral lesions of the talus.

METHODS

A retrospective cohort study comparing patients treated with BMS with EMCA (BMS-EMCA group) and BMS alone (BMS group) between 2013 and 2019 was undertaken. Clinical outcomes were evaluated with the Foot and Ankle Outcome Score (FAOS) preoperatively and postoperatively. Postoperative magnetic resonance imaging (MRI) scans were evaluated using the modified Magnetic Resonance Observation of Cartilage Repair Tissue score. Comparisons between groups were made with the Mann-Whitney U test for continuous variables and the Fisher exact test for categorical variables.

RESULTS

Twenty-four patients underwent BMS with EMCA (BMS-EMCA group), and 24 patients underwent BMS alone (BMS group). The mean age was 40.8 years (range, 19-60 years) in the BMS-EMCA group and 47.8 years (range, 24-60 years) in the BMS group (P = .060). The mean follow-up time was 20.0 months (range, 12-36 months) in the BMS-EMCA group and 26.9 months (range, 12-55 months) in the BMS group (P = .031). Both groups showed significant improvements in all FAOS subscales. No significant differences between groups were found in all postoperative FAOS values. The mean Magnetic Resonance Observation of Cartilage Repair Tissue score in the BMS-EMCA group was higher (76.3 vs 66.3) but not statistically significant (P = .176). The MRI analysis showed that 87.5% of the BMS-EMCA patients had complete infill of the defect with repair tissue; however, fewer than half of the BMS patients (46.5%) had complete infill (P = .015).

CONCLUSIONS

BMS with EMCA is an effective treatment strategy for osteochondral lesions of the talus and provides better cartilage infill in the defect on MRI. However, this did not translate to improved functional outcomes compared with BMS alone in the short term. Additionally, according to analysis of the minimal clinically important difference, there was no significant difference in clinical function scoring between the 2 groups postoperatively.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Lesion Size May Predict Return to Play in Young Elite Athletes Undergoing Microfracture for Osteochondral Lesions of the Talus

PURPOSE

To evaluate the clinical and sports-related outcomes of arthroscopic microfracture (MFx) for osteochondral lesion of the talus (OLT) in elite athletes.

METHODS

The athletes who underwent arthroscopic MFx for OLTs at our institution between January 2011 and September 2015 with minimum 2 years of follow-up were reviewed. The Foot and Ankle Outcome Score, American Orthopaedic Foot & Ankle Society, and visual analog scale pain score, time and rate of "return-to-competition" (RTC, return to an official match for at least 1 minute after treatment), and rate of "return-to-play" (RTP, participation in at least 2 entire seasons after treatment) were used to evaluate the outcomes. We compared athletes who were able to RTP with those who were not.

RESULTS

In total, 41 patients (mean age 19.34 ± 3.76 years) were included. The mean follow-up was 54.9 ± 13.72 months. In total, 36 patients had medial lesions, and 5 patients had lateral lesions. All subscales of preoperative Foot and Ankle Outcome Score were significantly improved at the final follow-up. The mean preoperative American Orthopaedic Foot & Ankle Society score of 74.46 ± 8.10 improved to 91.62 ± 2.99 (P < .001) at the final follow-up. The mean preoperative visual analog scale pain score of 5.44 ± 1.57 improved to 2.66 ± 1.04 (P < .001). All patients achieved RTC (100%) at mean time of 5.45 ± 3.18 months, and 74.4% of patients were able to RTP. The RTP-group showed significantly smaller lesions compared to the No-RTP group (71.52 ± 43.29 vs 107.00 ± 45.28 mm², P = .009). The cut-off OLT size for predicting RTP was 84.0 mm², with a sensitivity of 90.0% and specificity of 75.9%.

CONCLUSIONS

All athletes were able to RTC at average of 5.45 months after MFx for OLTs with minimal subchondral involvement, and 74.4% were able to RTP. The only prognostic variable for RTP was lesion size, and its predictive cut-off was 84.0 mm².

LEVEL OF EVIDENCE

IV, Case series.

Next-Generation Marrow Stimulation Technology for Cartilage Repair: Basic Science to Clinical Application

»

Given the relatively high prevalence of full-thickness articular cartilage lesions, including in patients who are <40 years of age, and an inability to detect some of these lesions until the time of arthroscopy, there is value in performing a single-stage cartilage procedure such as marrow stimulation (MS).

»

While the positive outcomes of first-generation MS (namely microfracture) have been observed to drop off after 24 months in several studies, improvements have been seen when compared with preoperative conditions for lesions that are 2 to 3 cm2 in size, and MS is considered to be a procedure with technical simplicity, fairly short surgical times, and relatively low morbidity. A recent study showed that autologous chondrocyte implantation (ACI) and osteochondral allograft (OCA) transplantation remain viable treatment options for chondral defects of the knee in the setting of failed MS.

»

Basic science principles that have been elucidated in recent years include (1) the creation of vertical walls during defect preparation, (2) an increased depth of subchondral penetration, (3) a smaller awl diameter, and (4) an increased number of subchondral perforations, which are all thought to help resolve issues of access to the mesenchymal stromal cells (MSCs) and the subchondral bone structure/overgrowth issues.

»

Pioneering and evolving basic science and clinical studies have led to next-generation clinical applications, such as a hyaluronic acid-based scaffold (ongoing randomized controlled trial [RCT]), an atelocollagen-based gel (as described in a recently published RCT), a micronized allogeneic cartilage scaffold (as described in a recently completed prospective cohort study), and a biosynthetic hydrogel that is composed of polyethylene glycol (PEG) diacrylate and denatured fibrinogen (as described in an ongoing prospective study).

»

This review summarizes important points for defect preparation and the recent advances in MS techniques and identifies specific scaffolding augmentation strategies (e.g., mesenchymal augmentation and scaffold stimulation [MASS]) that have the capacity to advance cartilage regeneration in light of recent laboratory and clinical studies.

Effect of Microfracture on Functional Outcomes and Subchondral Sclerosis Following Distraction Arthroplasty of the Ankle Joint

BACKGROUND

Treatment for post-traumatic osteoarthritis (PTOA) of the ankle remains challenging. Distraction arthroplasty (DA) is an alternative for patients who are averse to or poor candidates for arthrodesis or joint replacement. The purpose of this study was to examine the role of microfracture (MFX) and concentrated bone marrow aspirate (CBMA) on the outcome of patients undergoing DA for end-stage PTOA of the ankle joint.

METHODS

Ninety-five patients who underwent DA for the treatment of end stage PTOA from 2009 to 2014 were selected from the hospital ankle registry. Demographic data, functional activity levels, complications, and radiographs taken at 6, 12, 24, and 36 months postoperatively were reviewed. Foot and Ankle Outcome Scores (FAOS) were obtained at the same time intervals. A total of 78 patients were included in this study. Interventions were divided into 4 groups for comparison: DA+MFX (n = 8), DA+MFX+CBMA (n = 35), DA+CBMA (n = 22), and DA alone (n = 13).

RESULTS

Patients undergoing DA+MFX or DA+MFX+CBMA had significantly worse motion (P = .003) when compared with DA alone. Patients undergoing MFX had significantly reduced postoperative joint space and a greater length of time to return to activity when compared to subgroups not using MFX (P = .01). The use of MFX was associated with significantly lower FAOS scores.

CONCLUSION

The current study showed no benefit from MFX when combined with DA in the treatment of PTOA. CBMA may have helped mitigate the adverse effect of MFX but conferred no benefit when used with DA alone. DA remains a useful alternative to ankle arthrodesis and arthroplasty in patients with PTOA. However, MFX and biologic augmentation using CBMA appeared to have no additional benefit.

LEVEL OF EVIDENCE

Level III, comparative study.

Autologous Chondrocyte Implantation and Osteochondral Allograft Transplantation Render Comparable Outcomes in the Setting of Failed Marrow Stimulation

BACKGROUND

Marrow stimulation techniques (MSTs) such as subchondral drilling and microfracture are often chosen as first-line treatment options for symptomatic cartilage defects of the knee. When an MST fails, many cartilage restoration techniques are employed, including autologous chondrocyte implantation (ACI) and osteochondral allograft (OCA). However, a few series in the literature suggest that ACI after a failed MST results in inferior outcomes as compared with primary ACI.

PURPOSE/HYPOTHESIS

The purpose of this study was (1) to evaluate the clinical outcomes of ACI and OCA after a failed MST (secondary ACI and OCA) and compare them with the outcomes of primary ACI and OCA and (2) to compare clinical outcomes of secondary ACI and secondary OCA for refractory lesions involving the femoral condyle. The hypotheses were as follows: (1) secondary ACI will render inferior functional outcomes and an increased clinical failure rate as compared with primary ACI, (2) secondary OCA will render comparable results to primary OCA, and (3) secondary OCA will render superior outcomes to secondary ACI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients were retrospectively identified who underwent ACI and OCA for symptomatic chondral lesions of the knee refractory to a previous MST. Age-, sex-, and body mass index-matched groups of patients undergoing primary ACI and OCA were used as controls. Postoperative data were prospectively collected using several subjective scoring systems (Tegner, Lysholm, International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, 12-Item Short Form Health Survey). Groups were compared with regard to patient-reported outcomes, subjective satisfaction, clinical failure rate, and reoperation. Student t tests were used for continuous data, and chi-square tests were performed for categorical data.

RESULTS

A total of 359 patients were examined: 92 patients undergoing secondary ACI, 100 primary ACI, 88 secondary OCA, and 79 primary OCA. The mean patient age was 30.3 years (range, 14.9-49.9 years) at the time of ACI and 35.4 (range, 15-54.5) at the time of OCA. There was no difference between the primary and secondary groups with regard to postoperative functional scores, subjective satisfaction, reoperation rate, and clinical failure rate.

CONCLUSION

ACI and OCA are both viable treatment options for chondral defects of the knee, even in the setting of a failed MST. Secondary ACI renders functional outcomes, subjective satisfaction, and reoperation and failure rates comparable with primary ACI and secondary OCA.

Midterm Outcomes of Bone Marrow Stimulation for Primary Osteochondral Lesions of the Talus: A Systematic Review

Background:

Bone marrow stimulation (BMS) is a common surgical intervention in the treatment of small osteochondral lesions of the talus (OLTs). Evidence has shown good clinical outcomes after BMS in the short term, but several studies have shown less favorable results at midterm and long-term follow-up because of fibrocartilaginous repair tissue degeneration.

Purpose:

To evaluate the clinical and radiological outcomes of BMS in the treatment of primary OLTs at midterm and long-term follow-up and to investigate reported data in these studies.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search of the MEDLINE, Embase, and Cochrane Library databases was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Clinical and radiological outcomes as well as reported data were evaluated.

Results:

A total of 15 studies comprising 853 patients (858 ankles) were included at a weighted mean follow-up time of 71.9 months. There were 9 studies that used the American Orthopaedic Foot & Ankle Society (AOFAS) score, with a weighted mean postoperative score of 89.9. There were 3 studies that measured postoperative magnetic resonance imaging results in the midterm using the MOCART (magnetic resonance observation of cartilage repair tissue) scoring system and showed 48% of patients with complete filling, 74% with complete integration, and 76% with surface damage. There was a complication rate of 3.4% and a reoperation rate of 6.0% after BMS in the midterm.

Conclusion:

This systematic review found good clinical outcomes after BMS at midterm follow-up for primary OLTs. Radiological outcomes showed repair tissue surface damage in the majority of patients, which may be a harbinger for long-term problems. Data were variable, and numerous data were underreported. Further high-quality studies, a validated outcome scoring system, and further radiological reports at midterm follow-up are required to accurately assess the success of BMS in the midterm.

[Research progress in surgical procedures for osteochondral lesions of talus]

Objective

To summarize the research progress of surgical procedures in osteochondral lesions of the talus (OLT).

Methods

By consulting the related literature of OLT in recent years, the advantages and disadvantages of various surgical treatment schemes were analyzed and summarized.

Results

There are many surgical treatments for OLT, including bone marrow stimulation, osteochondral transplantation, autologous chondrocyte transplantation, and biologically assisted therapy. Various schemes have different indications and limitations. With the continuous development of various technologies, the effectiveness of OLT treatment will gradually improve.

Conclusion

There are still many difficulties and controversies in the treatment of OLT, and there is no unified treatment plan. It is suggested that individualized operation plan should be formulated according to the specific conditions of patients.

High reported rate of return to play following bone marrow stimulation for osteochondral lesions of the talus

PURPOSE

The purpose of this study is to systematically review the literature and to evaluate the reported rehabilitation protocols, return to play guidelines and subsequent rates and timing of return to play following bone marrow stimulation (BMS) for osteochondral lesions of the talus (OLT).

METHODS

MEDLINE, EMBASE and the Cochrane Library were searched according to the PRISMA guidelines in September 2017. The rate and timing of return to play was assessed. The rehabilitation protocols were recorded, including time to start range of motion, partial weight-bearing and complete weight-bearing.

RESULTS

Fifty-seven studies with 3072 ankles were included, with a mean age of 36.9 years (range 23-56.8 years), and a mean follow-up of 46.0 months (range 1.5-141 months). The mean rate of return to play was 86.8% (range 60-100%), and the mean time to return to play was 4.5 months (range 3.5-5.9 months). There was large variability in the reported rehabilitation protocols. Range of motion exercises were most often allowed to begin in the first week (46.2%), and second week postoperatively (23.1%). The most commonly reported time to start partial weight-bearing was the first week (38.8%), and the most frequently reported time of commencing full weight-bearing was 6 weeks (28.8%). Surgeons most often allowed return to play at 4 months (37.5%).

CONCLUSIONS

There is a high rate of return following BMS for OLT with 86.8% and the mean time to return to play was 4.5 months. There is also a significant deficiency in reported rehabilitation protocols, and poor quality reporting in return to play criteria. Early weightbearing and early postoperative range of motion exercises appear to be advantageous in accelerated return to sports.

LEVEL OF EVIDENCE

Level IV.

The Presence and Degree of Bone Marrow Edema Influence Midterm Clinical Outcomes After Microfracture for Osteochondral Lesions of the Talus

BACKGROUND

Subchondral bone marrow edema (BME) has been associated with articular cartilage loss, with the potential to be a negative prognostic indicator for clinical outcomes after microfracture. However, no single study has investigated the association between BME and clinical outcomes after microfracture for osteochondral lesions of the talus (OLTs) at midterm follow-up.

PURPOSE

To clarify the association between postoperative subchondral BME and clinical outcomes in patients treated with microfracture for OLTs at both short-term and midterm follow-up using a grading system that classified the extent of BME of the talus.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent microfracture between 2008 and 2013 were assessed at 2- and 4-year postoperative follow-up. BME was evaluated using magnetic resonance imaging, and the presence of subchondral BME was determined with fat-suppressed T2-weighted sequences. Clinical outcomes were evaluated using the Foot and Ankle Outcome Score (FAOS). P < .05 was considered to be statistically significant.

RESULTS

Forty-three (83%) of 52 eligible patients were included. No significant differences were found in the FAOS between the BME and no BME groups at 2-year follow-up (83.1 ± 6.5 vs 88.6 ± 8.0, respectively; P = .109), but there was a significant difference at 4-year follow-up (77.5 ± 11.1 vs 84.7 ± 8.4, respectively; P = .041). A significant difference was found among BME grades at 4-year follow-up (grade 0: 84.7 ± 7.4, grade 1: 80.1 ± 10.5, grade 2: 74.0 ± 10.3, and grade 3: 67.5 ± 7.1; P = .035). A post hoc analysis showed significant differences between grades 0 and 2, 0 and 3, and 1 and 3 ( P = .041, .037, and .048, respectively). In addition, at 4-year follow-up, a significant correlation was noted between the FAOS and BME grade ( r = -0.453, P = .003) but not at 2-year follow-up ( r = -0.212, P = .178). Seventy-four percent of patients still had subchondral BME at 4-year follow-up after microfracture for OLTs.

CONCLUSION

Patients with subchondral BME at midterm follow-up after microfracture for OLTs had worse clinical outcomes than those without subchondral BME. In addition, the degree of subchondral BME at midterm follow-up was correlated with clinical outcomes. However, at short-term follow-up, there were no significant differences in clinical outcomes based on both the presence and degree of BME, and no correlation was found between clinical outcomes and the degree of BME. The current study suggests that BME at short-term follow-up is a normal physiological reaction. However, BME at midterm follow-up after microfracture for OLTs may be pathological and is associated with poorer clinical outcomes.

Subchondral Pathology: Proceedings of the International Consensus Meeting on Cartilage Repair of the Ankle

BACKGROUND

The evidence supporting best practice guidelines in the field of cartilage repair of the ankle are based on both low quality and low levels of evidence. Therefore, an international consensus group of experts was convened to collaboratively advance toward consensus opinions based on the best available evidence on key topics within cartilage repair of the ankle. The purpose of this article is to report the consensus statements on "Subchondral Pathology" developed at the 2017 International Consensus Meeting on Cartilage Repair of the Ankle.

METHODS

Seventy-five international experts in cartilage repair of the ankle representing 25 countries and 1 territory were convened and participated in a process based on the Delphi method of achieving consensus. Questions and statements were drafted within 11 working groups focusing on specific topics within cartilage repair of the ankle, after which a comprehensive literature review was performed and the available evidence for each statement was graded. Discussion and debate occurred in cases where statements were not agreed upon in unanimous fashion within the working groups. A final vote was then held, and the strength of consensus was characterized as follows: consensus, 51% to 74%; strong consensus, 75% to 99%; unanimous, 100%.

RESULTS

A total of 9 statements on subchondral pathology reached consensus during the 2017 International Consensus Meeting on Cartilage Repair of the Ankle. No statements achieved unanimous support, but all statements reached strong consensus (greater than 75% agreement). All statements reached at least 81% agreement.

CONCLUSIONS

This international consensus statements regarding subchondral pathology of the talus derived from leaders in the field will assist clinicians in the assessment and management of this difficult pathology.