[Advances in the Treatment of Osteochondral Lesions of the Talus]

Osteochondral lesion of the talus (OLT) is a localized cartilage and subchondral bone injury of the talus trochlea. OLT is caused by trauma and other reasons, including osteochondritis dissecans of the talus (OCD) and talus osteochondral tangential fracture. OLT can develop from being asymptomatic to subchondral bone cysts accompanied by deep ankle pain. OLT tends to occur on the medial and lateral sides of the talar vault. OLT seriously affects the patients' life and work and may even lead to disability. Herein, we reviewed advances in the treatment of OLT and the strengths and weaknesses of various treatments. Different treatment methods, including conservative treatments and surgical treatments, can be adopted according to the different subtypes or clinical symptoms of OLT. Conservative treatments mostly relieve symptoms in the short term and only slow down the disease. In recent years, it has been discovered that platelet-rich plasma injection, microfracture, periosteal bone grafting, talar cartilage transplantation, allograft bone transplantation, reverse drilling under robotic navigation, and other methods can achieve considerable benefits when each of these treatment methods is applied. Furthermore, microfracture combined with platelet-rich plasma injections, microfracture combined with cartilage transplantation, and various other treatment methods combined with anterior talofibular ligament repair have all led to good treatment outcomes.

Osteochondral Regeneration in the Knee Joint with Autologous Peripheral Blood Stem Cells plus Hyaluronic Acid after Arthroscopic Subchondral Drilling: Report of Five Cases

BACKGROUND

Treatment of osteochondral defects (OCDs) of the knee joint remains challenging. The purpose of this study was to evaluate the clinical and radiological results of osteochondral regeneration following intra-articular injections of autologous peripheral blood stem cells (PBSC) plus hyaluronic acid (HA) after arthroscopic subchondral drilling into OCDs of the knee joint.

CASE PRESENTATION

Five patients with OCDs of the knee joint are presented. The etiology includes osteochondritis dissecans, traumatic knee injuries, previously failed cartilage repair procedures involving microfractures and OATS (osteochondral allograft transfer systems). PBSC were harvested 1 week after surgery. Patients received intra-articular injections at week 1, 2, 3, 4, and 5 after surgery. Then at 6 months after surgery, intra-articular injections were administered at a weekly interval for 3 consecutive weeks. These 3 weekly injections were repeated at 12, 18 and 24 months after surgery. Each patient received a total of 17 injections. Subjective International Knee Documentation Committee (IKDC) scores and MRI scans were obtained preoperatively and postoperatively at serial visits. At follow-ups of >5 years, the mean preoperative and postoperative IKDC scores were 47.2 and 80.7 respectively (p = 0.005). IKDC scores for all patients exceeded the minimal clinically important difference values of 8.3, indicating clinical significance. Serial MRI scans charted the repair and regeneration of the OCDs with evidence of bone growth filling-in the base of the defects, followed by reformation of the subchondral bone plate and regeneration of the overlying articular cartilage.

CONCLUSION

These case studies showed that this treatment is able to repair and regenerate both the osseous and articular cartilage components of knee OCDs.

Particulated Costal Hyaline Cartilage Allograft With Subchondral Drilling Improves Joint Space Width and Second-Look Macroscopic Articular Cartilage Scores Compared With Subchondral Drilling Alone in Medial Open-Wedge High Tibial Osteotomy

PURPOSE

To compare the articular cartilage regeneration based on second-look arthroscopy in patients who underwent medial open-wedge high tibial osteotomy (MOWHTO) combined with particulated costal hyaline cartilage allograft (PCHCA) implantation with those who underwent MOWHTO and subchondral drilling (SD). Moreover, we compared the clinical and radiographic outcomes between the groups.

METHODS

From January 2014 to November 2020, patients with full-thickness cartilage defect on the medial femoral condyle who underwent MOWHTO combined with PCHCA (group A) or SD (group B) were reviewed. Fifty-one knees were matched after propensity score matching. The status of regenerated cartilage was classified according to the International Cartilage Repair Society-Cartilage Repair Assessment (ICRS-CRA) grading system and Koshino staging system, based on second-look arthroscopic findings. Clinically, the Knee Injury and Osteoarthritis Outcome Score, the Western Ontario and McMaster Universities Osteoarthritis Index, and range of motion were compared. Radiographically, we compared the differences in the minimum joint space width (JSW) and change in JSW.

RESULTS

The average age was 55.5 years (range, 42-64 years), and the average follow-up period was 27.1 months (range, 24-48 months). Group A showed a significantly better cartilage status than group B based on the ICRS-CRA grading system and Koshino staging system (P < .001 and <.001, respectively). There were no significant differences in clinical and radiographic outcomes between groups. In group A, the minimum JSW at the last follow-up was significantly increased than that before surgery (P = .013), and a significantly greater increase in JSW was observed in group A (P = .025).

CONCLUSIONS

When performed with MOWHTO, the combination of SD and PCHCA was associated with superior articular cartilage regeneration on the ICRS-CRA grading and Koshino staging on second-look arthroscopy performed at a minimum of 2 years follow-up than SD alone. However, there was no difference in clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Effects of adipose tissue-derived stromal vascular fraction on osteochondral defects treated by hyaluronic acid-based scaffold: An experimental study

OBJECTIVES

This study aims to evaluate the effect of adipose-derived stromal vascular fraction (SVF) on osteochondral defects treated by hyaluronic acid (HA)-based scaffold in a rabbit model.

MATERIALS AND METHODS

Eighteen white New Zealand rabbits were randomly grouped into the experimental group (n=9) and control group (n=9). In all groups, osteochondral defects were induced on the weight-bearing surfaces of the right femoral medial condyles, and a HA-based scaffold was applied to the defect area with microfractures (MFs). In this study, 1 mL of adipose-derived SVF was injected into the knee joints of the rabbits in the experimental group. For histological and macroscopic evaluation, four rabbits were randomly selected from each group at Week 4, and the remaining rabbits were sacrificed at the end of Week 8. Macroscopic assessments of all samples were performed based on the Brittberg scoring system, and microscopic evaluations were performed based on the O'Driscoll scores.

RESULTS

Samples were taken at Weeks 4 and 8. At Week 4, the O'Driscoll scores were significantly higher in the control group than the experimental group (p=0.038), while there was no significant difference in the Brittberg scores between the two groups (p=0.108). At Week 8, the O'Driscoll score and Brittberg scores were statistically higher in the experimental group than in the control group (p=0.008 and p=0.007, respectively). According to the microscopic evaluation, at the end of Week 8, the cartilage thickness was greater in the experimental group, and nearly all of the defect area was filled with hyaline cartilage.

CONCLUSION

Application of adipose-derived SVF with MF-HA-based scaffold was better than MF-HA-based scaffold treatment in improving osteochondral regeneration. Therefore, it can be used in combination with microfracture and scaffold to accelerate cartilage regeneration, particularly in the treatment of secondary osteoarthritis.

Bone marrow stimulation decreases retear rates after primary arthroscopic rotator cuff repair: a systematic review and meta-analysis

BACKGROUND

Despite the optimization of biomechanical and patient factors in the setting of rotator cuff repair (RCR), postoperative retear rates remain high in many series reported in the literature. Preclinical studies have suggested bone marrow stimulation (BMS) at the rotator cuff footprint may reduce the rate of retear after RCR. The objective of this meta-analysis was to analyze the clinical evidence investigating the effect of arthroscopic RCR, with and without BMS, on rotator cuff healing and functional outcomes.

METHODS

PubMed, MEDLINE, Embase, and the Cochrane Library were searched through December 2017. Two reviewers selected studies based on the inclusion criteria and assessed methodologic quality. Pooled analyses were performed for continuous and binomial variables where appropriate.

RESULTS

Four studies (365 patients), including 2 Level I randomized controlled trials and 2 Level III retrospective comparative cohort studies were included. There was no statistical difference in the Disabilities of the Arm, Shoulder and Hand score, University of California Los Angeles Shoulder Rating Scale score, or the Constant score between the BMS and conventional repair groups. The pooled retear rates were 18.4% (28 of 152) and 31.8% (56 of 176) for patients treated with and without BMS, respectively. The pooled analysis of rotator cuff retear rates from the 4 studies (328 patients) showed a statistically significant difference favoring BMS over conventional repair (odds ratio, 0.42; 95% confidence interval, 0.25-0.73; P = .002; I² = 0%).

CONCLUSION

BMS reduces the retear rate after RCR but shows no difference in functional outcomes compared with conventional repair. This study provides evidence for the use of BMS as a potential cost-effective biological approach toward improving rotator cuff healing.

Low pH irrigation fluids have positive effect on intra-articular chondral healing

PURPOSE

The aim of this study was to evaluate the effect of Ringer's lactate (RL) solutions with different pH values on early histologic healing in a microfracture model in vivo. The null hypothesis of the presented study is that irrigation fluids with lower pH (6.4) have negative effects on fibrous cartilage healing.

METHODS

Eighteen Wistar albino rats were randomly divided into three groups. Anterior midline incision was performed. Microfracture procedure was performed with a 1.2 mm k-wire at the lateral femoral condyle of each knee. the skin was sutured and joints were irrigated for 30 min with low pH (6.4) RL in Group 1, high pH (7.6) RL in Group 2 and no irrigation in Group 3. Three rats from each group were randomly selected and killed on the 3rd and 7th day. On the 3rd day, the healed chondral area was examined. On the 3rd and 7th day, the chondral depth and morphology were evaluated. On the 7th day, bone cellularity was assessed with osteoblast; osteoclast number and bone quality were evaluated with trabecular area and the number of trabeculae.

RESULTS

Chondral healing area on the 3rd day was significantly higher in Group 1 compared to other groups. Chondral morphology was also qualitatively superior in Group 1 compared to other groups on the 3rd and 7th day. There were no differences in chondral depths between the groups on the 3rd day; however, increased chondral depths were observed in Group 1 on the 7th day. There were statistically significant increases in trabecular area and the number of trabeculae, as well as the number of osteoblasts and osteoclasts in Group 1 on the 7th day.

CONCLUSIONS

The presented study revealed that low pH irrigation fluids have positive effects on the healing characteristics of intra-articular fibrous cartilage after microfracture procedure in vivo. In light of this study, we can assume that lower pH solutions could be safely used during microfracture procedures and it can also facilitate intra-articular fibrous cartilage formation and cartilage healing. Selection of irrigation solution is also important for intra-articular fibrous cartilage healing after microfracture procedure in vivo.

Clinical and radiographic outcomes of chitosan-glycerol phosphate/blood implant are similar with hyaluronic acid-based cell-free scaffold in the treatment of focal osteochondral lesions of the knee joint

PURPOSE

To determine the clinical and radiographic efficacy of chitosan-glycerol phosphate/blood implant versus hyaluronic acid-based cell-free scaffold in patients with focal osteochondral lesion of the knee joint.

METHODS

Clinical data of 46 patients surgically treated using either chitosan-glycerol phosphate/blood implant (25 patients, Group 1) or hyaluronic acid-based cell-free scaffold (21 patients, Group 2) in combination with microfracture were retrospectively evaluated. All lesions were Outerbridge grade III or IV with a mean lesion size of 3.3 ± 0.7 cm². The mean follow-up time was 24.4 months. Visual analogue scale (VAS), Lysholm knee score, and Tegner activity scale were the instruments to evaluate the clinical status. Magnetic resonance observation of cartilage repair tissue (MOCART) system was used to analyze the characteristics of repair tissue.

RESULTS

No significant differences were detected between the groups regarding VAS, Lysholm, and Tegner scores at any time interval during the whole follow-up. The mean post-operative VAS and Lysholm scores at the latest follow-up was significantly better in cases with the lesion size ≤ 3 cm² in Group 1 (p = 0.001, p < 0.001, respectively). However, no significant differences according to the lesion size were detected in Group 2 (n.s.). Complete repair with the filling of the defect was achieved in 7 (28%) of the knees in Group 1 and it was 7 (33.3%) of the knees in Group 2 according to MOCART system at the latest follow-up.

CONCLUSION

Single-stage regenerative cartilage surgery using chitosan-glycerol phosphate/blood implant combined to microfracture for focal osteochondral lesions of the knee revealed similar clinical and radiographic outcomes with hyaluronic acid-based cell-free scaffold at short-term follow-up. However, clinical outcomes of hyaluronan scaffold were less sensitive to defect size than chitosan. With the advantages of no hypertrophic repair tissue formation as well as no need to arthrotomy during surgery, chitosan is an effective choice especially in patients with the lesion size ≤ 3 cm².

LEVEL OF EVIDENCE

III.

Failure After Osteochondral Allograft Transplantation with the Chondrofix Implant: A Report of Two Cases

CASE

This report describes 2 cases of failed decellularized "off-the-shelf" Chondrofix (Zimmer Biomet) osteochondral allografts within a year after implantation in a 44-year-old man and a 50-year-old woman.

CONCLUSION

Although it is a successful technique for cartilage repair, the use of osteochondral allograft transplantation has been limited by the availability of fresh grafts; therefore, decellularized osteochondral allografts recently have been developed. Physicians should be cautious when considering the use of these implants for the repair of articular cartilage lesions.

Donor-Site-Related Mechanical Symptoms Following Osteochondral Autograft Transfer: A Case Report

CASE

A 37-year-old woman presented with repetitive catching of the right knee 4 weeks after implantation of a 2-plug osteochondral autograft into the medial femoral condyle. The workup indicated that the symptoms were secondary to patellar engagement with the donor sites of the lateral aspect of the trochlea. She subsequently underwent osteochondral allograft implantation, resulting in painless, full range of motion with complete resolution of the mechanical symptoms.

CONCLUSION

It is important to consider donor-site morbidity following osteochondral autograft implantation, especially in patients with a relatively narrow distal aspect of the femur. Implantation of osteochondral allograft plugs in the symptomatic donor site is a feasible management option for this rarely reported complication.

Bone marrow-stimulating techniques in arthroscopic rotator cuff repair: a systematic review protocol

INTRODUCTION

Bone marrow-stimulating (BMS) techniques during arthroscopic rotator cuff repair surgery theoretically enhance the biological component for healing and hence improve tendon healing, but their efficacy remains unproven. The purpose of this review is to determine the effects and associated harms of BMS in arthroscopic rotator cuff repair surgery.

METHODS AND ANALYSIS

We will perform a systematic review and meta-analysis of randomised-controlled trials (RCTs) and retrospective cohort studies (RCS) that compare outcomes following BMS use against no use of BMS during arthroscopic rotator cuff repair surgery. We will search the databases including the Cochrane Central Register of Controlled Trials, Medline and Embase, and clinical trial registries for relevant studies. We will include studies published from start of indexing until 23 August 2018. Two reviewers will independently assess the eligibility for studies. For each included trial, we will conduct duplicate independent data extraction and risk of bias assessment. We will use the Cochrane Collaboration tool to assess the risk of bias of included RCTs, while we will use the Risk Of Bias In Non-randomised Studies - of Interventions tool to evaluate the risk of bias of RCS. We will perform a random-effects meta-analysis in calculating the pooled risk estimates when appropriate. We will assess the overall quality of the data for each individual outcome using the Grading of Recommendations, Assessments, Development and Evaluation approach. The primary outcomes are tendon healing rate, overall pain and shoulder functions. The secondary outcomes are the proportion of participants with adverse events related to interventions, the range of motion and the proportion of participants with return to previous activities.

ETHICS AND DISSEMINATION

We will report this review according to the guidance of the PRISMA statement. The results of this review will be disseminated through conference presentations and publications in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42018087161.

CT arthrography visualizes tissue growth of osteochondral defects of the talus after microfracture

PURPOSE

Little is known about the arthroscopic or radiographic outcomes after arthroscopic microfracture of osteochondral lesions of the talus (OLTs). The purpose of this study was to investigate tissue growth after arthroscopic microfracture of OLTs using computed tomography arthrography (CTA) and to identify the relationship between CTA findings and clinical outcomes. We hypothesized that the morphology of the repaired tissue would be similar to that of normal anatomy and correlate with the clinical outcomes.

METHODS

Forty-two ankles treated using arthroscopic microfracture of OLTs between 2009 and 2014 were monitored. CTA was performed post-operatively at 6 months and at 1 and 2 years after surgery. The post-operative thickness of the repaired tissue associated with OLT (grade) and the volume of the subchondral cystic lesions were evaluated using CTA. Clinical outcomes, including the pain visual analog scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) ankle functional scores, were evaluated and correlated with CTA.

RESULTS

The proportion of fully grown tissue (grade 3) increased over time; specifically, the rates were 12/40 (33.3%) at 6 months, 11/18 (61.1%) at 1 year, and 8/10 (80%) at 2 years after surgery (p = 0.005). The VAS pain (p < 0.001) and AOFAS scores (p < 0.001) were also improved at the final follow-up; however, they were not associated with repaired tissue thickness as shown by CTA (n.s.).

CONCLUSIONS

After microfracture of OLTs, tissue growth in the osteochondral defects was well visualized using CT arthrography and was observed in most cases. However, the CTA findings were not related to the clinical outcomes.

LEVEL OF EVIDENCE

IV.

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.

Subchondral drilling for articular cartilage repair: a systematic review of translational research

Articular cartilage defects may initiate osteoarthritis. Subchondral drilling, a widely applied clinical technique to treat small cartilage defects, does not yield cartilage regeneration. Various translational studies aiming to improve the outcome of drilling have been performed; however, a robust systematic analysis of its translational evidence was still lacking. Here, we performed a systematic review of the outcome of subchondral drilling for knee cartilage repair in translational animal models. A total of 12 relevant publications studying 198 animals was identified, detailed study characteristics were extracted, and methodological quality and risk of bias were analyzed. Subchondral drilling led to improved repair outcome compared with defects that were untreated or treated with abrasion arthroplasty for cartilage repair in multiple translational models. Within the 12 studies, considerable subchondral bone changes were observed, including subchondral bone cysts and intralesional osteophytes. Furthermore, extensive alterations of the subchondral bone microarchitecture appeared in a temporal pattern in small and large animal models, together with specific topographic aspects of repair. Moreover, variable technical aspects directly affected the outcomes of osteochondral repair. The data from this systematic review indicate that subchondral drilling yields improved short-term structural articular cartilage repair compared with spontaneous repair in multiple small and large animal models. These results have important implications for future investigations aimed at an enhanced translation into clinical settings for the treatment of cartilage defects, highlighting the importance of considering specific aspects of modifiable variables such as improvements in the design and reporting of preclinical studies, together with the need to better understand the underlying mechanisms of cartilage repair following subchondral drilling.

Advances for Treatment of Knee OC Defects

Osteochondral (OC) defects are prevalent among young adults and are notorious for being unable to heal. Although they are traumatic in nature, they often develop silently. Detection of many OC defects is challenging, despite the criticality of early care. Current repair approaches face limitations and cannot provide regenerative or long-standing solution. Clinicians and researchers are working together in order to develop approaches that can regenerate the damaged tissues and protect the joint from developing osteoarthritis. The current concepts of tissue engineering and regenerative medicine, which have brought many promising applications to OC management, are overviewed herein. We will also review the types of stem cells that aim to provide sustainable cell sources overcoming the limitation of autologous chondrocyte-based applications. The various scaffolding materials that can be used as extracellular matrix mimetic and having functional properties similar to the OC unit are also discussed.

Clinical Outcome of Total Knee Arthroplasty After Prior Microfracture: A Matched Cohort Study

Microfracture (MFX) is a common operation for articular cartilage lesions. Data for patients who underwent total knee arthroplasty (TKA) after previous MFX are limited. The purpose of this study was to determine the outcomes, complications, and factors that influence outcomes in patients with previous MFX compared with those without previous MFX. Between 2005 and 2014, twenty-one TKAs were performed at a single tertiary care academic institution in patients with prior history of MFX surgery. These patients were retrospectively reviewed and matched 2:1 to patients who did not undergo previous MFX (n=42). Knee Society Score (KSS) (Subjective [KSS-S] and Function [KSS-F]) and complications were documented. Mean KSS-S in the MFX group increased significantly less (52.9 to 77.6) (P<.01) compared with the control group (51.3 to 83.8) (P<.01). The MFX group also demonstrated significantly less improvement in KSS-F from 63.0 to 88.9 (P=.02), whereas the control group demonstrated improvement from 52.4 to 87.1 (P=.02). At 5 years, the failure rate was 4.8% in the MFX group and 2.4% in the control group. Multivariate analysis found that older age at TKA resulted in smaller improvement in KSS-S. Paired relationships between increased age and decreased preoperative range of motion and women with an increased body mass index negatively affected KSS-S. Survivorship was similar between groups, but patients with MFX had slightly less clinical improvement compared with a matched control group. This study suggests that underlying patient factors may limit clinical improvement compared with primary TKA. [Orthopedics. 2017; 40(3):e473-e478.].

Distal femoral medial closing wedge osteotomy for degenerative valgus knee : mid-term results in active patients

Distal femoral medial closing wedge osteotomy (DFMCWO) may be a valuable treatment for arthritic valgus knees in young and active adults, with the possible aim of procrastinating knee replacement. 32 valgus knees (mean age : 41.4±11.2) treated with DFMCWO were retrospectively reviewed. All the knees had a lateral compartment osteoarthritis graded I-II-III according to Kellgren Lawrence classification. 20 knees had osteochondral lesions, treated with microfractures (8) or bone marrow derived cells transplantation (12). Patients were clinically (IKDC, KOOS, NRS, Tegner) and radiologically evaluated. A mean follow-up of 62.12±15.65 was achieved. KOOS score peaked at 24 months, showed a decremental trend, achieved a final results of 79,59±17,14. Similar trend was evident for IKDC. The final NRS score was 2.73±1.82 ; the final Tegner score was 4.81±1.56. Radiographs showed degenerative progression in 5 knees : 2 patients underwent knee replacement at the final follow-up. DFMCWO is an effective treatment to treat osteoarthritic symptomatology, delay degenerative progression and avoid knee replacement in valgus knees at mid-term follow-up.

Analysis of Outcomes for High Tibial Osteotomies Performed With Cartilage Restoration Techniques

PURPOSE

To evaluate reported medium- to long-term outcomes after high tibial osteotomy (HTO) with associated cartilage restoration procedures.

METHODS

A review of the MEDLINE database was performed. The inclusion criteria were English language, clinical outcome study with HTO as the primary procedure, use of a form of cartilage repair included, and the mean follow-up period of at least 2 years. Each identified study was reviewed for study design, patient demographics, type of procedures performed, clinical outcomes, progression to total knee arthroplasty, and complications.

RESULTS

Eight hundred and twenty-seven patients (839 knees) were included. The most common cartilage preservation technique used in conjunction with HTO was microfracture (4 studies; 22.2%). The mean Lyscholm scores, reported in 50% of the studies, ranged from 40 to 65.7 preoperatively and improved to a range of 67 to 94.6 postoperatively. Four studies (22.2%) used a visual analog scale for evaluation of pain and all had a mean visual analog scale of less than 3 postoperatively. Among studies evaluating conversion to arthroplasty, the rate of conversion was 6.8% and the range of mean number of years from HTO to conversion was 4.9 to 13.0. The overall reported complication rate was 10.3%.

CONCLUSIONS

HTO with cartilage restoration procedures provides reliable improvement in functional status in the medium- to long-term period after surgery and has potential to delay or avoid the need for knee arthroplasty surgery.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

Osteochondral Autograft Transfer Versus Microfracture in the Knee: A Meta-analysis of Prospective Comparative Studies at Midterm

PURPOSE

To compare microfracture (MFX) and osteochondral autograft transfer (OAT) surgical techniques to determine (1) postoperative activity level, (2) subjective patient outcomes, (3) failure rates, and (4) assess if any lesion characteristics favored one technique over the other.

METHODS

A comprehensive review of literature was performed of all studies comparing MFX and OAT. Studies included were all prospective studies that reported on activity-based outcome measures such as Tegner activity scores and subjective outcomes such as the International Knee Documentation Committee score. Failure rates, as determined by the publishing authors, were recorded for each study. Meta-analyses were conducted using a random-effects model. Paired standardized mean differences (Hedges's g to account for small sample bias) were used for continuous outcome measures, and risk ratios (Mantel-Haenszel method for small sample bias) for dichotomous outcome measures.

RESULTS

Six prospective studies satisfied the eligibility criteria and included 249 patients (186 male, 120 female) with an average age of 26.4 years and follow-up of 67.2 months. Tegner scores were superior in patients treated with OAT compared with MFX (ΔOAT-MFX for pre-post scores = 0.94 Tegner points, standardized mean difference [SMD] = 0.469, P = .005). Failure rates of MFX were higher than OAT (OAT = 11%, MFX = 32%, risk ratio = 2.42, P < .036). OAT was superior to MFX at 3 years in relation to subjective outcome scores (SMD = 0.404, P = .008). When assessing OAT lesions larger than 3 cm², OAT was superior to MFX with respect to activity level (SMD = 0.506, P = .001).

CONCLUSIONS

OAT may achieve higher activity levels and lower risk of failure when compared with MFX for cartilage lesions greater than 3 cm² in the knee, although there was no significant difference for lesions less than 3 cm² at midterm. However, because of variability in patient-specific factors such as age, preinjury activity level, lesion location and size, the superiority of OAT over MFX cannot be generalized to all patient populations and therefore requires individualized patient care.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and II studies.

Mesenchymal stem cell therapy in the treatment of osteoarthritis: reparative pathways, safety and efficacy - a review

Osteoarthritis is a leading cause of pain and disability across the world. With an aging population its prevalence is likely to further increase. Current accepted medical treatment strategies are aimed at symptom control rather than disease modification. Surgical options including joint replacement are not without possible significant complications. A growing interest in the area of regenerative medicine, led by an improved understanding of the role of mesenchymal stem cells in tissue homeostasis and repair, has seen recent focused efforts to explore the potential of stem cell therapies in the active management of symptomatic osteoarthritis. Encouragingly, results of pre-clinical and clinical trials have provided initial evidence of efficacy and indicated safety in the therapeutic use of mesenchymal stem cell therapies for the treatment of knee osteoarthritis. This paper explores the pathogenesis of osteoarthritis and how mesenchymal stem cells may play a role in future management strategies of this disabling condition.

Protective effects of tumor necrosis factor-α blockade by adalimumab on articular cartilage and subchondral bone in a rat model of osteoarthritis

We aimed to investigate the effects of an anti-tumor necrosis factor-α antibody (ATNF) on cartilage and subchondral bone in a rat model of osteoarthritis. Twenty-four rats were randomly divided into three groups: sham-operated group (n=8); anterior cruciate ligament transection (ACLT)+normal saline (NS) group (n=8); and ACLT+ATNF group (n=8). The rats in the ACLT+ATNF group received subcutaneous injections of ATNF (20 μg/kg) for 12 weeks, while those in the ACLT+NS group received NS at the same dose for 12 weeks. All rats were euthanized at 12 weeks after surgery and specimens from the affected knees were harvested. Hematoxylin and eosin staining, Masson's trichrome staining, and Mankin score assessment were carried out to evaluate the cartilage status and cartilage matrix degradation. Matrix metalloproteinase (MMP)-13 immunohistochemistry was performed to assess the cartilage molecular metabolism. Bone histomorphometry was used to observe the subchondral trabecular microstructure. Compared with the rats in the ACLT+NS group, histological and Mankin score analyses showed that ATNF treatment reduced the severity of the cartilage lesions and led to a lower Mankin score. Immunohistochemical and histomorphometric analyses revealed that ATNF treatment reduced the ACLT-induced destruction of the subchondral trabecular microstructure, and decreased MMP-13 expression. ATNF treatment may delay degradation of the extracellular matrix via a decrease in MMP-13 expression. ATNF treatment probably protects articular cartilage by improving the structure of the subchondral bone and reducing the degradation of the cartilage matrix.

An educational review of cartilage repair: precepts & practice--myths & misconceptions--progress & prospects

OBJECTIVE

The repair of cartilaginous lesions within synovial joints is still an unresolved and weighty clinical problem. Although research activity in this area has been indefatigably sustained, no significant progress has been made during the past decade. The aim of this educational review is to heighten the awareness amongst students and scientists of the basic issues that must be tackled and resolved before we can hope to escape from the whirlpool of stagnation into which we have fallen: cartilage repair redivivus!

DESIGN

Articular-cartilage lesions may be induced traumatically (e.g., by sports injuries and occupational accidents) or pathologically during the course of a degenerative disease (e.g., osteoarthritis). This review addresses the biological basis of cartilage repair and surveys current trends in treatment strategies, focussing on those that are most widely adopted by orthopaedic surgeons [viz., abrasive chondroplasty, microfracturing/microdrilling, osteochondral grafting and autologous-chondrocyte implantation (ACI)]. Also described are current research activities in the field of cartilage-tissue engineering, which, as a therapeutic principle, holds more promise for success than any other experimental approach.

RESULTS AND CONCLUSIONS

Tissue engineering aims to reconstitute a tissue both structurally and functionally. This process can be conducted entirely in vitro, initially in vitro and then in vivo (in situ), or entirely in vivo. Three key constituents usually form the building blocks of such an approach: a matrix scaffold, cells, and signalling molecules. Of the proposed approaches, none have yet advanced beyond the phase of experimental development to the level of clinical induction. The hurdles that need to be surmounted for ultimate success are discussed.

Surgical management of osteochondritis dissecans lesions of the patella and trochlea in the pediatric and adolescent population

BACKGROUND

There is a paucity of published data regarding the management of osteochondritis dissecans (OCD) lesions of the patellofemoral joint in children and adolescents.

PURPOSE

To evaluate the functional outcomes of surgical management of OCD lesions of the patella and trochlea in children and adolescents. Secondary aims included elucidating predictors for higher functional outcomes and determining complication rates, surgical satisfaction, and ability to return to sports.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients aged 18 years and younger who were surgically treated for OCD of the patella or trochlea were identified. Charts were queried to record patient/lesion data, surgical procedure, results, and complications. Pre- and postoperative imaging was reviewed. Patients were asked to complete a follow-up athletic questionnaire and a Pediatric International Knee Documentation Committee (Pedi-IKDC) questionnaire. Statistical analysis was conducted to look for predictors for reoperation, residual pain, ability to return to sports, and lower Pedi-IKDC scores.

RESULTS

A total of 26 children (9 females, 17 males, 3 with bilateral lesions; thus, 29 lesions) were identified. The mean age was 14.7 years (range, 9-18, years), 21 of the 29 knees with lesions (72%) had open physes, and median follow-up was 3.8 years (range, 1-9 years). The most common location was the trochlea (17/29 lesions; 59%). Twenty-two lesions (76%) underwent transarticular drilling (n = 14) or drilling with fixation (n = 8), while 7 underwent excision and marrow stimulation. Four patients (14%) required unplanned reoperation. Internal fixation was predictive of reoperation (odds ratio [OR] = 8.7; 95% CI, 2.8-26.9; P = .04). At final follow-up, 14 knees (48%) were pain free, and 14 (48%) had mild residual pain. Female sex was predictive of residual pain (OR, 9; 95% CI, 2-56; P = .02). Twenty-two patients (85%) returned to sports. Longer duration of preoperative pain negatively affected return to sports (OR, 0.32; 95% CI, 0.05-0.97; P = .04). On postoperative MRI, the lesion appeared completely healed in 2 cases (18%) and partially healed in 9 cases (82%). All 15 survey respondents were satisfied with surgery. The mean Pedi-IKDC score was 82.4 ± 17.8 (range, 40.2-100).

CONCLUSION

Surgical treatment of patellofemoral OCD in children and adolescents produces a high rate of satisfaction and return to sports. Female sex, prolonged duration of symptoms, and internal fixation may be associated with worse outcomes.

[Chondrocytes application in regenerative medicine]

Cartilage reconstruction is a crucial issue for tissue engineering because of high damage frequency in connection with low regenerative capacity. Microfractures and shaving are the oldest and most commonly used practices. The newest techniques are: Autologous Chondrocyte Implantation, Matrix Associated Chondrocytes Implantation and their derivatives. Dedifferentiation of chondrocytes due to low proliferation rate and phenotype loss makes isolation and in vitro culture of normal human chondrocytes very complex. Therefore, obtaining mesenchymal stem cells from various sources and differentiating them into chondrocytes is another interesting approach.

Tissue engineering stratified scaffolds for articular cartilage and subchondral bone defects repair

Due to their good biocompatibility and mechanical integrity, tissue engineering scaffolds have become a principal method of repair and regeneration of osteochondral defects. To improve their intrinsic properties, control their degenerative times, and enhance their cell adhesion and differentiation, numerous scaffold architectures and formation methods have been developed and tested, but the ideal scaffold design is still controversial. Moreover, scaffold fixation has a significant influence on repair and regeneration after implantation. The authors analyzed relative studies to address the latest scaffold designs, including biphasic scaffold, multilayered scaffold, and continuous nonstratified scaffold, and this article compares their advantages and disadvantages. In addition, the authors introduce a novel modified method for scaffold fixation known as magnetic fixation. Both stratified and nonstratified scaffolds can repair osteochondral defects, but continuous nonstratified scaffolds are more biomimetic compared with the native osteochondral structures, and they lead to a better regeneration of hyaline-like cartilage and structured bone tissue. Therefore, the authors suggest continuous nonstratified scaffolds are an effective option for treating osteochondral defects.

[Treatment of cartilaginous defects in the knee: recommendations from the Dutch Orthopaedic Association]

Cartilaginous defects in the knee occur frequently and can cause the patient considerable limitations. They are diagnosed and classified by means of MRI and arthroscopy. The surgical options available to treat deep chondral lesions include bone marrow stimulation techniques (microfracture treatment), chondrocyte therapies (autologous chondrocyte implantation) and tissue replacement therapies (osteochondral autologous transplantation). Microfracture treatment and osteochondral autologous transplantation are suitable for treating chondral lesions that extend to the subchondral bone and are smaller than 2 and 4 cm2, respectively. Autologous chondrocyte implantation is a suitable method for treating single symptomatic chondral lesions larger than 2 cm2 in adults up to 50 years of age. There are no significant differences regarding the effectiveness of microfracture treatment, autologous chondrocyte implantation and osteochondral autologous transplantation for small defects: all show good clinical and functional short- and medium-term results. New second- and third-generation autologous chondrocyte implantation techniques seem to yield more sustainable tissue repair and better clinical long-term results for lesions larger than 4 cm2 in comparison to microfracture treatment.

Treatment of cartilage defects by subchondral drilling combined with covering with atelocollagen membrane induces osteogenesis in a rat model

BACKGROUND

The coverage of the atelocollagen membrane at the chondral defect after subchondral drilling might improve the beneficial effects for cartilage repair because of the prevention of scattering and accumulation of cells and growth factors from bone marrow within the chondral defect. On the other hand, it might block cells and factors derived from the synovium or cause high pressure in the chondral defect, resulting in prevention of cells and growth factors gushing out from the bone marrow, which leads to disadvantages for cartilage repair.

METHOD

We tested this hypothesis in a 2-mm-diameter chondral defect created in the articular cartilage of the patellar groove in a rat models. Defects were left untreated, or were drilled or drilled and covered with an atelocollagen membrane; healing was evaluated by histology and gene expression analysis using real-time polymerase chain reaction and immunohistochemistry.

RESULTS

Membrane coverage induced bone tissue ingrowth into the punched chondral defect. At 1 week, expression of TGFβ, Sox9, Runx2, osteocalcin, Col1a1, and Col2a1 in the drilling group was significantly higher than in the covering group. At 4 weeks, expressions of TGFβ, Runx2, and Col1a1 were all significantly higher in the drilling group, while Sox9, osteocalcin, and Col2a1 were significantly higher in the covering group. Immunohistochemistry demonstrated Sox9, osteocalcin, and type II collagen on the bony reparative tissue in the covering group.

CONCLUSIONS

These results suggest that the atelocollagen membrane coverage resulted in inhibition of cartilage repair.

[Experimental research on repairing full-thickness articular cartilage defects by transplantation of autologous uncultured bone-marrow-derived mononuclear cells in combination with micro-fracture]

OBJECTIVE

To examine the feasibility of autologous uncultured bone-marrow-derived mononuclear cells (BM-MNCs) in combination with microfracture in a full-thickness articular cartilage defect model so as to provide experimental rationales for clinical applications.

METHODS

A total of 40 rabbits were divided randomly into groups A, B, C and D (n = 10 each). In groups A and C, 5 ml marrow samples were harvested from left femur and then autologous BM-MNCs isolated. The full-thickness articular cartilage defects were made on femoral intercondylar fossa in right knees of rabbits. Group A: micro-fracture was made on cartilage defect and then autologous uncultured BM-MNCs-autologous fibrin gel complex implanted; Group B:the same micro-fracture was made on cartilage defect and autologous fibrin gel implanted; Group C:the cartilage defect was implanted with autologous uncultured BM-MNCs-autologous fibrin gel complex; Group D:the cartilage defect was implanted with autologous fibrin gel. Five rabbits were sacrificed at Weeks 8 and 12 post-transplantation in each group. And the reparative tissue samples evaluated grossly, histologically and immunohistochemically were graded according to the gross and histological scales.

RESULTS

The statistical analyses of histological gradings at Weeks 8 and 12 showed that group A was significantly better than groups B, C and D (P < 0.05), groups B and C were better than group D (P < 0.05) and each group at Week 12 was better than itself at Week 6 (P < 0.05).

CONCLUSION

Both of micro-fracture and transplantation of uncultured autologous BM-MNCs plus autologous fiber gel can promote the repair of cartilage defects. The combined use of micro-fracture and autologous uncultured BM-MNCs promotes the regeneration of articular cartilage so that it may provide theoretical rationales for clinical applications.

Cartilage repair of the ankle: first results of T2 mapping at 7.0 T after microfracture and matrix associated autologous cartilage transplantation

BACKGROUND

Both microfracture (MFX) and matrix associated autologous cartilage transplantation (MACT) are currently used to treat cartilage defects of the talus. T2 mapping of the ankle at 7 T has the potential to assess the collagen fibril network organization of the native hyaline cartilage and of the repair tissue (RT). This study provides first results regarding the properties of cartilage RT after MFX (mean follow-up: 113.8 months) and MACT (65.4 months).

METHODS

A multi-echo spin-echo sequence was used at 7 T to assess T2 maps in 10 volunteer cases, and in 10 cases after MFX and MACT each. Proton weighted morphological images and clinical data were used to ensure comparable baseline criteria.

RESULTS

A significant zonal variation of T2 was found in the volunteers. T2 of the superficial and the deep layer was 39.3 ± 5.9 ms and 21.1 ± 3.1 ms (zonal T2 index calculated by superficial T2/deep T2: 1.87 ± 0.2, P < 0.001). In MFX, T2 of the reference cartilage was 37.4 ± 5.0 ms and 25.3 ± 3.5 ms (1.51 ± 0.3, P < 0.001). In the RT, T2 was 43.4 ± 10.5 ms and 36.3 ± 7.7 ms (1.20 ± 0.2, P = 0.009). In MACT, T2 of the reference cartilage was 39.0 ± 9.1 ms and 27.1 ± 6.6 ms (1.45 ± 0.2, P < 0.001). In the RT, T2 was 44.6 ± 10.4 ms and 38.6 ± 7.3 ms (1.15 ± 0.1, P = 0.003). The zonal RT T2 variation differed significantly from the reference cartilage in both techniques (MFX: P = 0.004, MACT: P = 0.001).

CONCLUSION

T2 mapping at 7 T allows for the quantitative assessment of the collagen network organization of the talus. MACT and MFX yielded RT with comparable T2 properties.

Assessment of articular cartilage repair tissue after matrix-associated autologous chondrocyte transplantation or the microfracture technique in the ankle joint using diffusion-weighted imaging at 3 Tesla

OBJECTIVE

The objective was to compare patients after matrix-associated autologous chondrocyte transplantation (MACT) and microfracture therapy (MFX) of the talus using diffusion-weighted imaging (DWI), with morphological and clinical scoring.

MATERIALS AND METHODS

Twenty patients treated with MACT or MFX (10 per group) were examined using 3 T magnetic resonance imaging (MRI) at 48 ± 21.5 and 59.6 ± 23 months after surgery, respectively. For comparability, patients from each group were matched by age, body mass index, and follow-up. American Orthopaedic Foot and Ankle Society (AOFAS) score served as clinical assessment tool pre- and postoperatively. DWI was obtained using a partially balanced, steady-state gradient echo pulse sequence, as well as the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, based on a 2D proton density-weighted turbo spin-echo sequence and a 3D isotropic true fast imaging with steady-state precession sequence. Semi-quantitative diffusion quotients were calculated after region of interest analysis of repair tissue (RT) and healthy control cartilage, and compared among both groups.

RESULTS

The mean AOFAS score improved significantly (P = 0.001) for both groups (MACT: 48.8 ± 20.4-83.6 ± 9.7; MFX: 44.3 ± 16.5-77.6 ± 13.2). No differences in the AOFAS (P = 0.327) and MOCART (P = 0.720) score were observed between MACT and MFX postoperatively. DWI distinguished between healthy cartilage and cartilage RT in the MFX group (P = 0.016), but not after MACT treatment (P = 0.105). Significant correlations were found between MOCART score and DWI index after MFX (Pearson: -0.648; P = 0.043), and between the diffusivity and longer follow-up interval in MACT group (Pearson: -0.647, P = 0.043).

CONCLUSION

Whereas conventional scores reveal a similar outcome after MACT or MFX treatment in the ankle joint, DWI was able to distinguish between different RT qualities, as reported histologically for these diverse surgical procedures.

The treatment of cartilage defects in the knee joint: microfracture, mosaicplasty, and autologous chondrocyte implantation

The efficacy of microfracture (MF), mosaicplasty (MO), and autologous chondrocyte implantation (ACI) techniques are still a matter of debate. This review aims to analyze comparative studies of these techniques, review the results of no treatment, and the natural history of untreated articular cartilage lesions. A PubMed search on the topic was performed. The most important (14) articles, as judged by the author, were selected for this review. There is limited evidence that any intervention significantly alters the natural history of these lesions and there is no evidence of significant difference between ACI and MF and MO. Paramount for successful surgical cartilage repair is a stable knee with a well-aligned lower limb. There is insufficient evidence at present to say that ACI is cost-effective, compared with MF or MO.

Assessment of articular cartilage repair tissue after matrix-associated autologous chondrocyte transplantation or the microfracture technique in the ankle joint using diffusion-weighted imaging at 3 Tesla

OBJECTIVE

The objective was to compare patients after matrix-associated autologous chondrocyte transplantation (MACT) and microfracture therapy (MFX) of the talus using diffusion-weighted imaging (DWI), with morphological and clinical scoring.

MATERIALS AND METHODS

Twenty patients treated with MACT or MFX (10 per group) were examined using 3 T magnetic resonance imaging (MRI) at 48 ± 21.5 and 59.6 ± 23 months after surgery, respectively. For comparability, patients from each group were matched by age, body mass index, and follow-up. American Orthopaedic Foot and Ankle Society (AOFAS) score served as clinical assessment tool pre- and postoperatively. DWI was obtained using a partially balanced, steady-state gradient echo pulse sequence, as well as the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, based on a 2D proton density-weighted turbo spin-echo sequence and a 3D isotropic true fast imaging with steady-state precession sequence. Semi-quantitative diffusion quotients were calculated after region of interest analysis of repair tissue (RT) and healthy control cartilage, and compared among both groups.

RESULTS

The mean AOFAS score improved significantly (P = 0.001) for both groups (MACT: 48.8 ± 20.4-83.6 ± 9.7; MFX: 44.3 ± 16.5-77.6 ± 13.2). No differences in the AOFAS (P = 0.327) and MOCART (P = 0.720) score were observed between MACT and MFX postoperatively. DWI distinguished between healthy cartilage and cartilage RT in the MFX group (P = 0.016), but not after MACT treatment (P = 0.105). Significant correlations were found between MOCART score and DWI index after MFX (Pearson: -0.648; P = 0.043), and between the diffusivity and longer follow-up interval in MACT group (Pearson: -0.647, P = 0.043).

CONCLUSION

Whereas conventional scores reveal a similar outcome after MACT or MFX treatment in the ankle joint, DWI was able to distinguish between different RT qualities, as reported histologically for these diverse surgical procedures.

Cartilage quality assessment by using glycosaminoglycan chemical exchange saturation transfer and (23)Na MR imaging at 7 T

PURPOSE

To compare a glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging method, which enables sampling of the water signal as a function of the presaturation offset (z-spectrum) at 13 points in clinically feasible imaging times, with sodium 23 ((23)Na) magnetic resonance (MR) imaging in patients after cartilage repair surgery (matrix-associated autologous chondrocyte transplantation and microfracture therapy).

MATERIALS AND METHODS

One female patient (67.3 years), and 11 male patients (median age, 28.8 years; interquartile range [IQR], 24.6-32.3 years) were examined with a 7-T whole-body system, with approval of the local ethics committee after written informed consent was obtained. A modified three-dimensional gradient-echo sequence and a 28-channel knee coil were used for gagCEST imaging. (23)Na imaging was performed with a circularly polarized knee coil by using a modified gradient-echo sequence. Statistical analysis of differences and Spearman correlation were applied.

RESULTS

The median of asymmetries in gagCEST z-spectra summed over all offsets from 0 to 1.3 ppm was 7.99% (IQR, 6.33%-8.79%) in native cartilage and 5.13% (IQR, 2.64%-6.34%) in repair tissue. A strong correlation (r = 0.701; 95% confidence interval: 0.21, 0.91) was found between ratios of signal intensity from native cartilage to signal intensity from repair tissue obtained with gagCEST or (23)Na imaging. The median of dimensionless ratios between native cartilage and repair tissue was 1.28 (IQR, 1.20-1.58) for gagCEST and 1.26 (IQR, 1.21-1.48) for (23)Na MR imaging.

CONCLUSION

The high correlation between the introduced gagCEST method and (23)Na imaging implies that gagCEST is a potentially useful biomarker for glycosaminoglycans.

Autologous chondrocytes. Autologous chondrocyte implantation: more data needed

There is no standard surgical treatment for young adults with persistent, incapacitating symptoms of knee cartilage damage. ChondroCelect is the first cell therapy product to be authorised in the European Union. It contains a dense suspension of chondrocytes cultured from a biopsy of the patient's knee cartilage for 4 weeks before being reimplanted. Clinical evaluation of Chondro-Celect only includes one trial, versus subchondral microfracture, in 118 patients. After 3 years of follow-up, there was no difference in the symptom score between the groups. Histological outcome was better after autologous chondrocyte implantation, but methodological problems make it difficult to interpret the observed difference. Long-term functional outcomes remain to be determined. More joint complications occurred after autologous chondrocyte implantation than after subchondral bone microfracture: more frequently symptomatic cartilage hypertrophy (27% versus 13%, possibly related to the implantation technique), joint swelling (22% versus 6.6%), joint effusion (24% versus 9.8%), and joint crepitations (18% versus 6.6%). Autologous chondrocyte implantation was sometimes associated with flu-like syndrome (in 7.8% of patients), which did not occur with the microfracture technique. Autologous chondrocyte implantation is more complex than microfracture. During routine use, there is a risk that one patient will inadvertently receive chondrocytes collected from another patient, leading to a risk of rejection. In practice, this autologous chondrocyte product should only be used by highly specialised teams, and its assessment must continue.

Resurfacing of isolated articular cartilage defects in the glenohumeral joint with microfracture: a surgical technique & case report

Isolated, full-thickness chondral lesions of the glenohumeral joint remain significant problems for athletes, workers, and the elderly. Microfracture has been established as an effective therapeutic solution for such cartilage defects of the knee, because of its low surgical morbidity and ease as a first-line treatment with good clinical outcomes. Although the indications for microfracture and the surgical techniques are similar for cartilage injuries of the shoulder and knee joints, the literature includes no reviews of the use of microfracture in the humeral head or glenoid surface. Overall, microfracture is a minimally invasive, technically simple surgical procedure that provides an excellent option for patients with isolated full-thickness chondral defects. In this article, we describe the subtleties of microfracture in the glenohumeral joint and outline the clinical course of a typical patient.

An in vitro model of biomaterial-augmented microfracture including chondrocyte-progenitor cell interaction

BACKGROUND

Biomaterials, acting as scaffolds for cell migration and differentiation, may be used to improve outcomes after microfracture. Three mechanisms determine the success of such procedures and are tested herein: the general capacity of adult femoral mesenchymal progenitor cells (MPC) to differentiate into cartilage, their capacity to do so in a biomaterial, and finally potential interactions between MPC and autologous chondrocytes.

METHODS

Human adult chondrocytes and MPC were obtained with informed consent and cultured individually or in co-culture on a collagenous biomaterial. Differentiation potential of MPC was assessed using PCR and proliferation and biosynthesis were compared to test for differences between individual cultures and co-cultures. Finally, potential interaction between chondrocytes and MPC was assessed by comparing the observed levels of proliferation and biosynthesis with those expected in independent growth.

RESULTS

We found that adult femoral marrow-derived MPC have the potential to differentiate into multiple lineages, and, seeded in a biomaterial, show similar differentiation when compared with autologous chondrocytes. Finally, there was a strong indication for an interaction between MPC and chondrocytes in biosynthetic activity, which was twice as high as would be expected in independent cell activity. Proliferation rates were unaffected.

CONCLUSION

Our study showed that biomaterial-augmented microfracture is a viable option in cartilage repair from a biological perspective because adult femoral MPC have a strong capacity to differentiate into chondrocytes, which is further enhanced by the surrounding cartilage. Failure in in vivo studies must be explained by other factors of the intra-articular environment, such as cytokines or biomechanics.

Current strategies for nonsurgical, arthroscopic, and minimally invasive surgical treatment of knee cartilage pathology

The current approaches to treating articular cartilage defects in the knee comprise a spectrum from pharmacologic therapies to total knee arthroplasty. Nonsurgical treatment can include anti-inflammatory medications, bracing, and physical therapy. Surgical treatments include reconstructive repair of a small or large defect using microfracture, osteochondral autograft transplantation, autologous chrondrocyte transplantation, or osteochondral allograft transplantation; realignment procedures including osteotomies; and unicompartmental arthroplasty. A comprehensive algorithm can be used to determine the appropriate treatment for knee defects.

[Treatment options for cartilage damage in the knee joint]

The complex structure of articular cartilage is essential for understanding biology and function. Despite performing with a relatively low metabolic activity, healthy articular cartilage has amazing capacity to sustain itself and carry out its function. Chondrocytes are active in maintaining the tissue's matrix, showing differences in the anatomic structure. Articular cartilage has extraordinary mechanical properties and lasting durability. It is only a few millimetres thick. The cartilage wears resistance while bearing large loads throughout a person's lifetime. Otherwise we see cartilage destructions in young patients without a trauma. It is important to know that the articular cartilage decreases with age. The ability of the MRI to obtain reproducible, accurate images of cartilage has enabled early detection of cartilage lesions and provides clinically relevant information when planning cartilage repair. MRI depicts the subchondral bone and all other anatomic structures of the knee. This information is vital when planning for complex techniques that require careful size delineation of the cartilage lesion and evaluation of the surrounding subchondral bone. In addition to aiding in preoperative planning, the MRI offer an important objective evaluation of cartilage repair to be correlated with the more subjective clinical outcome instruments and provide insight into the biology of the repair process. The repair strategies are currently available for clinical use when treating articular cartilage lesions. These strategies fall into one of the following categories: 1. Palliative-conservative treatment (local or systemic application), 2. Intrinsic-repair enhancement/marrow stimulation (drilling, microfracture, arthroplasty), 3. Cell-based repair (collagen associated chondrocyte transplantation or microfracture with collagen). The use of biodegradable scaffolds can be used either alone or as delivery vehicles for growths factors. This technique could be a new way for winning structurally and biomechanically appropriate tissue.

Repair of articular cartilage and clinical outcome after osteotomy with microfracture or abrasion arthroplasty for medial gonarthrosis

This study compared the healing of articular cartilage and the clinical outcome after osteotomy with or without marrow stimulation microfracture or abrasion arthroplasty for osteoarthritis of the knee. Patients with osteoarthritis of the medial compartment of the knee were divided into a group undergoing high tibial osteotomy alone (HTO group: 37 knees), a group undergoing osteotomy plus microfracture (MF group: 26 knees), and a group undergoing osteotomy plus abrasion arthroplasty (AA group: 51 knees). The extent of cartilage repair was compared at 1 year after surgery by arthroscopy with reference to Outerbridge's classification, while the clinical outcome was compared at 1, 3, and 5 years postoperatively. Second-look arthroscopy revealed better repair of the femoral condylar cartilage in the AA group than the HTO group (p<0.0005) or MF group (p<0.01), with no difference between the HTO and MF groups. Repair of the tibial condylar cartilage was also better in the AA group than the HTO group (p<0.005), but there was no difference between the AA and MF groups or the MF and HTO groups. There were no differences of the clinical outcome between the three groups. In conclusion, repair of articular cartilage at 1 year postoperatively was accelerated by abrasion arthroplasty, but not by microfracture. However, there was no difference of the clinical outcome within 5 years after surgery, so the clinical utility of marrow stimulation techniques was not apparent in this study.

Regeneration of ovine articular cartilage defects by cell-free polymer-based implants

The aim of our study was the evaluation of a cell-free cartilage implant that allows the recruitment of mesenchymal stem and progenitor cells by chemo-attractants and subsequent guidance of the progenitors to form cartilage repair tissue after microfracture. Chemotactic activity of human serum on human mesenchymal progenitors was tested in 96-well chemotaxis assays and chondrogenic differentiation was assessed by gene expression profiling after stimulating progenitors with hyaluronan in high-density cultures. Autologous serum and hyaluronan were combined with polyglycolic acid (PGA) scaffolds and were implanted into full-thickness articular cartilage defects of the sheep pre-treated with microfracture. Defects treated with microfracture served as controls. Human serum was a potent chemo-attractant and efficiently recruited mesenchymal progenitors. Chondrogenic differentiation of progenitors upon stimulation with hyaluronan was shown by the induction of typical chondrogenic marker genes like type II collagen and aggrecan. Three months after implantation of the cell-free implant, histological analysis documented the formation of a cartilaginous repair tissue. Controls treated with microfracture showed no formation of repair tissue. The cell-free cartilage implant consisting of autologous serum, hyaluronan and PGA utilizes the migration and differentiation potential of mesenchymal progenitors for cartilage regeneration and is well suited for the treatment of cartilage defects after microfracture.

International Cartilage Repair Society (ICRS) and Oswestry macroscopic cartilage evaluation scores validated for use in Autologous Chondrocyte Implantation (ACI) and microfracture

OBJECTIVE

For young patients with cartilage defects, the emergence of clinically applicable cell therapy for biological joint reconstruction is an appealing prospect. Acceptation of this method as a means of standard care requires proof of being reproducible, having long-lasting mechanical integrity, and having a good clinical outcome. This study evaluates the reliability of the International Cartilage Repair Society (ICRS) score and the Oswestry Arthroscopy Score (OAS) in the assessment of regenerative cartilage repair.

METHOD

A total of 101 macroscopic images of cartilage repair were made during arthroscopy 12 months post-treatment of either Autologous Chondrocyte Implantation (ACI) or microfracture. These images were examined by seven independent observers with differing levels of experience. The ICRS and OAS scores were randomly presented twice at a 4-week interval. All observers stated their predicted outcome according to actual treatment and defect size.

RESULTS

ICRS and OAS scores showed both good inter- and intra observer reliability (0.62 and 0.56 for ICRS; 0.73 and 0.65 for OAS, respectively). Internal consistency (Cronbach's alpha) was satisfactory for research purposes (0.79 and 0.74, respectively). Correlation (equivalence concordance) between both scoring systems was excellent (r=0.94). All observers were inconsistent in predicting actual treatment. Test-re test reliability of estimated defect size and its correlation to true defect size were poor. These results were also applicable to the sub-analyses of the experience of the observer and the quality of imaging.

CONCLUSION

The ICRS and OAS are reliable and relevant scores that are now both validated for macroscopic evaluation of cartilage repair as a research tool.

[Osteochondritis dissecans of the ankle]

PURPOSE

The aim of this study was to determine the efficacy of the microfracture method in the treatment of symptomatic osteochondral lesion of the talus.

MATERIALS AND METHODS

24 patients operated by the mentioned method were prospectively followed-up. Standard radiological treatment was performed in all patients, ankle CT was performed in 10 patients, and MR was performed in 8 patients. Patients' subjective satisfaction with operation was assessed by SANE and Martin's score, while the objective function was assessed by AOFAS and Freiburg's score.

RESULTS

The mean preoperative AOFAS score was 53 (from 31 to 61), while the mean postoperative AOFAS score was 87.5 (from 81 to 100). Postoperative Freiburg's score was 89.5 (from 76 to 100). The distribution of treatment outcomes was evaluated by the Martin's score and it revealed excellent, good and satisfying results in 94.5% patients, while the distribution of outcomes by the SANE questionnaire revealed excellent and good result in 91.8% patients.

CONCLUSION

The arthroscopy of the ankle with microfractures is safe, cheap and effective method in the treatment of osteochondral lesions.