Clinical Outcome and Return to Competition after Microfracture in the Athlete's Knee: An Evidence-Based Systematic Review

Knee Cartilage Injuries in Football Players: Clinical Outcomes and Return to Sport After Surgical Treatment: A Systematic Review of the Literature

OBJECTIVE

To systematically review the literature and analyze clinical outcomes and return-to-sport after surgical management of cartilage injuries in football players.

DESIGN

A systematic literature review was performed in August 2023 on PubMed, WebOfScience, and Cochrane Library to collect studies on surgical strategies for cartilage lesions in football players. Methodological quality and risk of bias were assessed with the modified Coleman Methodology score and RoB2 and RoBANS2 tools.

RESULTS

Fifteen studies on 409 football players (86% men, 14% women) were included: nine prospective and two retrospective case series, one randomized controlled trial, one prospective comparative study, one case report, and one survey. Bone marrow stimulation (BMS) techniques were the most documented. The lesion size influenced the treatment choice: debridement was used for small lesions (1.1 cm2), BMS, osteochondral autograft transplantation (OAT), matrix-assisted autologous chondrocytes transplantation (MACT), and scaffold-augmented BMS for small/mid-size lesions (2.2-3.0 cm2), and autologous chondrocytes implantation (ACI) for larger lesions (5.8 cm2). The surgical options yielded different results in terms of clinical outcome and return-to-sport, with fastest recovery for debridement and scaffold-augmented BMS. The current evidence is limited with large methodological quality variation (modified Coleman Methodology score 43.5/100) and a high risk of bias.

CONCLUSIONS

Decision-making in cartilage injuries seems to privilege early return-to-sport, making debridement and microfractures the most used techniques. The lesion size influences the treatment choice. However, the current evidence is limited. Further studies are needed to confirm these findings and establish a case-based approach to treat cartilage injuries in football players based on the specific patient and lesion characteristics and the treatments' potential in terms of both return-to-sport and long-term results.

LEVEL OF EVIDENCE

Systematic review, level IV.

Treatment of Knee Chondral Defects in Athletes

Cartilage lesions of the knee are a challenging problem, especially for active individuals and athletes who desire a return to high-load activities. They occur both through chronic repetitive loading of the knee joint or through acute traumatic injury and represent a major cause of pain and time lost from sport. They can arise as isolated lesions or in association with concomitant knee pathology. Management of these defects ultimately requires a sound understanding of their pathophysiologic underpinnings to help guide treatment. Team physicians should maintain a high index of suspicion for underlying cartilage lesions in any patient presenting with a knee effusion, whether painful or not. A thorough workup should include a complete history and physical examination. MRI is the most sensitive and specific imaging modality to assess these lesions and can provide intricate detail not only of the structure and composition of cartilage, but also of the surrounding physiological environment in the joint. Treatment of these lesions consists of both conservative or supportive measures, as well as surgical interventions designed to restore or regenerate healthy cartilage. Because of the poor inherent capacity for healing associated with hyaline cartilage, the vast majority of symptomatic lesions will ultimately require surgery. Surgical treatment options range from simple arthroscopic debridement to large osteochondral reconstructions. Operative decision-making is based on numerous patient- and defect-related factors and requires open lines of communication between the athlete, the surgeon, and the rest of the treatment team. Ultimately, a positive outcome is based on the creation of a durable, resistant repair that allows the athlete to return to pain-free sporting activities.

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.

Comparison of Hydrogel-Based Autologous Chondrocyte Implantation Versus Microfracture: A Propensity Score Matched-Pair Analysis

Background

Few studies exist for large defects comparing matrix-associated autologous chondrocyte implantation (M-ACI) with other cartilage repair methods due to the limited availability of suitable comparator treatments.

Purpose

To compare the clinical efficacy of a novel hydrogel-based M-ACI method (NOVOCART Inject plus) versus microfracture (MFx) in patients with knee cartilage defects.

Study Design

Cohort study; Level of evidence, 3.

Methods

Propensity score matched-pair analysis was used to compare the 24-month outcomes between the M-ACI treatment group from a previous single-arm phase 3 study and the MFx control group from another phase 3 study. Patients were matched based on preoperative Knee injury and Osteoarthritis Outcomes Score (KOOS), symptom duration, previous knee surgeries, age, and sex, resulting in 144 patients in the matched-pair set (72 patients per group). The primary endpoint was the change in least-squares means (ΔLSmeans) for the KOOS from baseline to the 24-month assessment.

Results

Defect sizes in the M-ACI group were significantly larger than in the MFx group (6.4 versus 3.7 cm2). Other differences included defect location (no patellar or tibial defects in the MFx group), number of defects (33.3% with 2 defects in the M-ACI group versus 9.7% in the MFx group), and defect cause (more patients with degenerative lesions in the M-ACI group). The M-ACI group had higher posttreatment KOOS (M-ACI versus MFX: 81.8 ± 16.8 versus 73.0 ± 20.6 points) and KOOS ΔLSmeans from baseline to 24 months posttreatment (M-ACI versus MFX: 36.9 versus 26.9 points). Treatment contrasts in KOOS ΔLSmeans from baseline indicated statistical significance in favor of M-ACI from 3 to 24 months posttreatment (P = .0026). Significant and clinically meaningful differences in favor of M-ACI at 24 months were also found regarding International Knee Documentation Committee (IKDC) score ΔLSmeans from baseline (37.8 versus 30.4 points; P = .0334), KOOS responder rates at 24 months (≥10-point improvement from baseline; 94.4% versus 65.3%; P < .0001), IKDC responder rates at 24 months (>20.5-point improvement from baseline; 83.3% versus 61.1%, P = .0126) and MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score in a subgroup of patients (LS means, 86.9 versus 69.1; P = .0096).

Conclusion

In this exploratory analysis, M-ACI using an in situ crosslinked hydrogel demonstrated superior clinical and structural (MOCART) 24-month outcomes compared with MFx in patients with knee cartilage defects.

Return to Pivoting Sports after Cartilage Repair Surgery of the Knee: A Scoping Review

OBJECTIVE

To perform a scoping literature review evaluating and reporting on outcomes and return to pivoting sports after cartilage procedures. For this review, the following cartilage procedures were evaluated: microfracture, osteochondral autograft transplantation (OAT), osteochondral allograft transplantation (OCA), and autologous chondrocyte implantation (ACI).

DESIGN

The scoping review incorporated articles identified using PubMed (MEDLINE), CINAHL, and Cochrane Central Register of Controlled Trials. Screening of reference lists of included studies and forward citation tracking were performed to identify additional studies. Reported on return to pivoting sports after cartilage surgery written in English language.

RESULTS

Sixteen studies fulfilled the inclusion criteria. The return to sports (RTS) rates after microfracture ranged from 44% to 83%, and to preinjury level from 25% to 75%. The RTS rates after OAT ranged from 87% to 100%, and to preinjury level from 67% to 93%. The RTS rates after OCA ranged from 77% to 80%, and to preinjury level 64%. The RTS rates after ACI ranged from 33% to 96%, and to preinjury level from 26% to 67%.

CONCLUSIONS

There was a high heterogeneity and range in rates of RTS in athletes participating in pivoting sports. Most studies reported high rates of RTS; however, return to preinjury level was lower. These data may be important to clinicians in shared decision making on the type of procedure to be performed and counseling pivoting sports athletes on prognosis and expected RTS rates.

Biological Reconstruction of Localized Full-Thickness Cartilage Defects of the Knee: A Systematic Review of Level 1 Studies with a Minimum Follow-Up of 5 Years

OBJECTIVE

The objective of this study was to evaluate the best available mid- to long-term evidence of surgical procedures for the treatment of localized full-thickness cartilage defects of the knee.

DESIGN

Systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines of Level 1 randomized clinical trials (RCTs), meta-analyses of RCTs and systematic reviews with a minimum follow-up of 5 years. Data extracted included patient demographics, defect characteristics, clinical and radiological outcomes, as well as treatment failures.

RESULTS

Six RCTs and 3 Level 1 systematic reviews were included. Two RCTs compared microfracture (MFx) to periosteum-covered autologous chondrocyte implantation (ACI-P), 1 to matrix-associated ACI (M-ACI) and 2 to osteochondral autograft transplantation (OAT). One study compared OAT to collagen membrane covered ACI (ACI-C). The 3 Level 1 systematic reviews/meta-analyses assessed the outcome of MFx, OAT, and various ACI methods in RCTs. OAT showed significantly better outcomes compared with MFx. In the 2 RCTs comparing ACI-P and MFx, no significant differences in clinical outcomes were seen, whereas significantly better outcomes were reported for M-ACI versus MFx in 1 study including patients with larger defects (5 cm²), and for ACI-C versus OAT in terms of Cincinnati Score. Higher failure rates were reported for MFx compared with OAT and for OAT compared with ACI-C, while no significant differences in failure rates were observed for ACI-P compared to MFx.

CONCLUSION

Restorative cartilage procedures (ACI-C or M-ACI and OAT) are associated with better long-term clinical outcomes including lower complication and failure rates when compared with reparative techniques (MFx). Among the restorative procedures, OAT seems to be inferior to ACI especially in larger defects after longer follow-up periods.

LEVEL OF EVIDENCE

Level I: Systematic review of Level I studies.

Treatment of Cartilage Defects of the Knee in Military Tactical Athletes: An Overview of Management and Clinical Outcomes

Cartilage defects of the knee are a common problem that can be caused by trauma or chronic repetitive overload and result in debilitating functional limitations. These consequences are of particular significance to military service members, who, by in large, are a group of young, active individuals with professional duties requiring full, unrestricted activity and function. The burden of knee chondral-related disease among military tactical athletes is well established, and systematic approach to the evaluation of a military member with suspected knee chondral pathology facilitates the execution of a surgical procedure that maximizes the likelihood of a return to duty. Despite advances in cartilage restoration surgery, chondral pathology of the knee remains a vexing problem and an omnipresent threat to military medical readiness and warfighter lethality.

Osteochondral Allograft Transplantation of the Lateral Femoral Condyle and Distal Femoral Osteotomy in the Setting of Failed Osteochondritis Dissecans Fixation

Osteochondritis dissecans (OCD) is a pathologic condition, most commonly affecting the knee joint in adolescents and young adults, although pathology can also be found at the elbow and ankle. Lesions to the medial femoral condyle are classically associated with varus alignment, while lesions to the lateral femoral condyle are seen in patients with valgus malalignment. Common risk factors for failed fixation of OCD lesions include unstable lesions to the lateral femoral condyle, screw breakage, older age, and closed physes. The purpose of this technical note is to describe the preoperative planning and step-by-step surgical approach for treatment of failed fixation of an OCD lesion of the posterior aspect of the lateral femoral condyle in young, active patients using an osteochondral allograft, a lateral opening wedge distal femoral osteotomy to correct malalignment, and a tibial tubercle osteotomy to facilitate access to the lesion.

Rehabilitation Variability Following Femoral Condyle and Patellofemoral Microfracture Surgery of the Knee

OBJECTIVE

To assess the variability of postoperative rehabilitation protocols used by orthopedic surgery residency programs for microfracture of femoral condyle and patellofemoral lesions of the knee.

DESIGN

Online postoperative microfracture rehabilitation protocols from US orthopedic programs and the scientific literature were reviewed. A custom scoring rubric was developed to analyze each protocol for the presence of discrete rehabilitation modalities and the timing of each intervention.

RESULTS

A total of 18 programs (11.6%) from 155 US academic orthopedic programs' published online protocols and a total of 44 protocols were analyzed. Seventeen protocols (56.7%) recommended immediate postoperative bracing for femoral condyle lesions and 17 (89.5%) recommended immediate postoperative bracing for patellofemoral lesions. The average time to permitting weight-bearing as tolerated (WBAT) was 6.1 weeks (range, 0-8) for femoral condyle lesions and 3.7 weeks (range, 0-8 weeks) for patellofemoral lesions. There was considerable variation in the inclusion and timing of strength, proprioception, agility, and pivoting exercises. For femoral condyle lesions, 10 protocols (33.3%) recommended functional testing prior to return to sport at an average of 23.3 weeks postoperatively (range, 12-32 weeks). For patellofemoral lesions, 4 protocols (20.0%) recommended functional testing for return to sport at an average of 21.0 weeks postoperatively (range, 12-32 weeks).

CONCLUSION

A minority of US academic orthopedic programs publish microfracture rehabilitation protocols online. Among the protocols currently available, there is significant variability in the inclusion of specific rehabilitation components and timing of many modalities. Evidence-based standardization of elements of postoperative rehabilitation may help improve patient care and subsequent outcomes.

Functional Outcomes and Return to Sport After Cartilage Restoration of the Knee in High-level Athletes

Articular cartilage injuries of the knee are being observed with increasing frequency in athletes and have proven to be difficult to treat given the limited regenerative ability of cartilage and the potential for progressive joint degeneration. A wide range of surgical treatments such as microfracture, autologous chondrocyte implantation, and osteochondral autograft and allograft have demonstrated promising results in these high-demand individuals. These procedures permit healing of cartilage defects while decreasing pain and restoring function with patient-reported outcomes demonstrating significant improvement at short-, mid-, and long-term follow-up. Most athletes are able to return to play after cartilage restoration of the knee, regardless of the surgical technique used. Although there is a large degree of heterogeneity across the literature and no consensus as to the optimal technique, osteochondral autograft transfer seems to offer the highest rate of return to sport and return to play at preinjury level. However, autologous chondrocyte implantation and osteochondral allograft transplantation are often used for larger defects or salvage after previous procedures, so results may be confounded. In addition, a multitude of factors including patient history, characteristics of the chondral lesion, and postoperative management may affect functional outcomes in athletes.

An In Vitro Study to Determine the Feasibility of Combining Bone Marrow Concentrate with BST-CarGel as a Treatment for Cartilage Repair

OBJECTIVE

The study aims were to determine whether BST-CarGel, a chitosan scaffold for cartilage repair, can be mixed with bone marrow aspirate concentrate (BMAC) to create a cell seeded implant with comparative properties to standard BST-CarGel mixed with blood.

DESIGN

Whole blood and bone marrow were harvested from 12 patients who underwent cartilage repair surgery using BMAC after informed consent. A validated in vitro testing model was used to assess the following 6 conditions: (1) BST-CarGel mixed with whole blood (CG-WB), (2) BST-CarGel mixed with bone marrow (CG-BM), (3) BST-CarGel mixed with bone marrow concentrate (CG-BMAC), (4) whole blood (WB), (5) bone marrow (BM), and (6) bone marrow concentrate and batroxobin (BMAC-BTX). Cell retention and viability within the BST-CarGel/BMAC clots were investigated.

RESULTS

In our study, BM and BMAC (processed using the Harvest, SmartPrep2 system and reactivated with batroxibin) when combined with BST-CarGel produced a product that had similar clot contraction, macroscopic properties, and histological appearance to standard BSTCarGel mixed with blood. Mononucleated cells from the BMAC were retained within the scaffold and remained viable until clot dissolution in vitro.

CONCLUSIONS

By combining BST-CarGel with BMAC in the manner described, bone marrow-derived mononucleated cells can be retained within the chondral defect potentially negating the need for microfracture. Further in vivo work is required to confirm these potential benefits and determine if this combination will result in more durable cartilage repair and improved clinical outcomes.

Postoperative Management for Articular Cartilage Surgery in the Knee

The postoperative rehabilitation team plays a crucial role in optimizing outcomes after articular cartilage surgery. A comprehensive approach to postoperative physical therapy that considers the type of surgery, location in the knee, concurrent procedures, and patient-specific factors is imperative. While postoperative rehabilitation protocols should be specific to the patient and type of surgery performed and include phased rehabilitation goals and activities, the key principles for postoperative rehabilitation apply across the spectrum of articular cartilage surgeries and patients. These key principles consist of preoperative assessments that include physical, mental, and behavioral components critical to recovery; education and counseling with respect to expectations and compliance; and careful monitoring and adjustments throughout the rehabilitation period based on consistent communication among rehabilitation, surgical, and imaging teams to ensure strict patient compliance with restrictions, activities, and timelines to optimize functional outcomes after surgery.

Return-to-Sport Review for Current Cartilage Treatments

The return to play outcome is an important measure for orthopaedic sports medicine treatments. This variable is especially important when discussing cartilage treatments because there are many different cartilage options available to athletes with articular injuries and this population is particularly interested in the ability to return to activities. Although many outcome variables are considered in any surgical procedure, the return-to-sport variable is focused on an active population and can be tailored to that patient's sport-specific goals. In this article, we will review some of the most recent and up-to-date articles describing return-to-sport outcomes for various knee cartilage treatments. This article will focus on the most common current knee cartilage treatments including microfracture, autologous chondrocyte implantation, osteochondral autograft transplant, and osteochondral allograft transplantation.

Small Cartilage Defect Management

Cartilage defects in the knee are common resulting in significant pain and morbidity over time. These defects can arise in isolation or concurrently with other associated injuries to the knee. The treatment of small (< 2-3 cm²) cartilage deficiencies has changed as our basic science knowledge of tissue healing has improved. Advancements have led to the development of new and more effective treatment modalities. It is important to address any associated knee injuries and limb malalignment. Surgical options are considered when nonoperative treatment fails. The specific procedure depends on individual patient characteristics, lesion size, and location. Debridement/chondroplasty, microfracture, marrow stimulation plus techniques, fixation of unstable osteochondral fragments, osteochondral autograft transfer, and osteochondral allograft transplantation, all have roles in the treatment of small cartilage defects.

Cartilage Injury in the Knee: Assessment and Treatment Options

Cartilage injuries in the knee are common and can occur in isolation or in combination with limb malalignment, meniscus, ligament, and bone deficiencies. Each of these problems must be addressed to achieve a successful outcome for any cartilage restoration procedure. If nonsurgical management fails, surgical treatment is largely based on the size and location of the cartilage defect. Preservation of the patient's native cartilage is preferred if an osteochondral fragment can be salvaged. Chondroplasty and osteochondral autograft transfer are typically used to treat small (<2 cm) cartilage defects. Microfracture has not been shown to be superior to chondroplasty alone and has potential adverse effects, including cyst and intralesional osteophyte formation. Osteochondral allograft transfer and matrix-induced autologous chondrocyte implantation are often used for larger cartilage defects. Particulated juvenile allograft cartilage is another treatment option for cartilage lesions that has good to excellent short-term results but long-term outcomes are lacking.

Current Applications of Growth Factors for Knee Cartilage Repair and Osteoarthritis Treatment

PURPOSE OF REVIEW

The decreased contact area, edge loading, and increased stress in the adjacent area cartilage resulting from chondral defects are believed to predispose this tissue to degenerative changes that have significant economic implications, especially when considering its progression to osteoarthritis of the knee. Growth factors are considered therapeutic possibilities to enhance healing of chondral injuries and modify the progression to degenerative arthritis. Thus, the purposes of this review are to first to summarize important points for defect preparation and recent advances in techniques for marrow stimulation and second, and to identify specific growth factors and cytokines that have the capacity to advance cartilage regeneration and the treatment of osteoarthritis in light of recent laboratory and clinical studies.

RECENT FINDINGS

TGF-β, BMP-2, BMP-7, IGF-1, as IL-1 receptor antagonist, and recombinant human FGF-18 are some of the promising growth factor/cytokine treatments with pioneering and evolving clinical developments. The bulk of the review describes and discusses these developments in light of fundamental basic science. It is crucial to also understand the other underlying advances made in the surgical management of cartilage defects prior to onset of OA. These advances are in techniques for defect preparation and marrow stimulation, a common cartilage repair procedure used in combination with growth factor/cytokine augmentation. Multiple growth factor/cytokine modulation therapies are currently undergoing clinical trial investigation including Invossa (currently in phase III study), Kineret (currently in phase I study), and Sprifermin (currently in phase II study) for the treatment of symptomatic osteoarthritis.

Clinical outcome after treatment of single and multiple cartilage defects by autologous matrix-induced chondrogenesis

PURPOSE

Characterized cartilage lesions have a distinct impact on postoperative clinical outcome, which is still being evaluated. The purpose of this study was to assess the postoperative clinical outcome of autologous matrix-induced chondrogenesis (AMIC) for characterized cartilage lesions.

METHODS

Fifteen patients with articular cartilage (AC) defects of the knee were included in the study. AC defects were characterized intraoperatively by International Cartilage Repair Society score. Grade III-IV AC lesions were treated with AMIC; grade I-II lesions were left untreated. Patients were divided into subgroups and clinically evaluated by subjective autologous matrix-induced chondrogenesis (IKDC) and Tegner scores at median follow-up of 4.5 years.

RESULTS

Twenty-eight AC defects were diagnosed (1.9/patient). Multiple subgroup had larger diagnosed (7 ± 2.3 cm², p = 0.022) and untreated (3.1 ± 2.3 cm², p = 0.012) lesion areas than the single subgroup. Partly treated subgroup had larger untreated defect areas (3.6±2.3 cm², p = 0.025) than the Treated subgroup. Average subjective IKDC values of total group and individual subgroups improved significantly at follow-up. More patients restored their previous activity levels ( p = 0.026) and had higher incremental subjective IKDC scores ( p = 0.014) in the single subgroup than the multiple subgroup. Diagnosed defect size negatively correlated to subjective IKDC incremental ( r = -0.624, p = 0.023) and postoperative scores ( r = -0.545, p = 0.054) in total group.

CONCLUSIONS

AMIC can have a clinically relevant outcome for patients with single or multiple knee AC lesions; however, clinical outcome is superior in patients with a single defect per knee. Patients with single defects returned to previous physical activity levels significantly faster than patients with multiple defects. Diagnosed AC defect areas negatively correlate to clinical improvement at follow-up.

Preservation of Knee Articular Cartilage

Hyaline articular cartilage is critical for the normal functioning of the knee joint. Untreated focal cartilage defects have the potential to rapidly progress to diffuse osteoarthritis. Over the last several decades, a variety of interventions aiming at preserving articular cartilage and preventing osteoarthritis have been investigated. Reparative cartilage procedures, such as microfracture, penetrate the subchondral bone plate in effort to fill focal cartilage defects with marrow elements and stimulate fibrocartilaginous repair. In contrast, restorative cartilage procedures aim to replace the defective articular surface with autologous or allogeneic hyaline cartilage. This review focuses on the preservation of articular cartilage, and discusses the current reparative and restorative surgical techniques available for treating focal cartilage defects.

[Cartilage repair of the knee joint]

BACKGROUND

Cartilage defects around the knee joint frequently occur in the region of the medial femoral condyle and the retropatellar cartilage surface. The distinction between local cartilage defects and large area degenerative cartilage lesions is very important for both prognosis and surgical therapy. The size and position of the lesion, the underlying pathomechanism and the age of the patient are very important factors which should be considered in the therapy algorithm for optimal cartilage defect restoration. Important cofactors such as stability, long leg axis and muscle balance should be taken into account.

AIM

Current procedures for cartilage repair of the knee joint and their results are summarized in this article. In addition, the necessity of precise and comprehensive preoperative clinical and radiological diagnostics is displayed to be able to treat co-pathologies in order to enable a successful repair of the cartilage defect.

RESULTS AND CONCLUSIONS

Preoperative planning of cartilage-repair techniques usually includes x‑ray images and a magnetic resonance imaging (MRI) examination. If MRI is not available, an arthro-computed tomography could be an alternative. Modern and routinely used procedures for cartilage repair at the knee joint are microfracture, autologous matrix-induced chondrogenesis, autologous chondrocyte transplantation, matrix-induced autologous chondrocyte implantation and osteochondral transplantation. Successful surgical cartilage-repair surgeries require a correct and individualized indication, addressing of copathologies and a standardized rehabilitation that is adapted to the surgical procedure. Evidence-based criteria for an exact time point for the return to sports according to individually operative cartilage repair techniques currently do not exist.

Can Competitive Athletes Return to High-Level Play After Osteochondral Allograft Transplantation of the Knee?

PURPOSE

To investigate functional outcomes among competitive athletes undergoing osteochondral allograft (OCA) transplantation of the knee, including rates of return to play (RTP), and factors preventing RTP.

METHODS

A retrospective review identified all competitive athletes (high school, intercollegiate, professional) undergoing isolated femoral condyle OCA from 2004 to 2013. Patient-reported outcome (PRO) questionnaires (Lysholm, International Knee Documentation Committee [IKDC], Knee Injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMasters Universities Arthritis Index [WOMAC], 12-Item Short Form Health Survey [SF-12], Tegner, and Marx) and custom RTP surveys were administered. All subsequent reoperations were documented.

RESULTS

Thirteen athletes (4 intercollegiate, 9 high-school) were identified with an average follow-up of 5.9 ± 2.5 years. Seven athletes (54%) returned to competitive sport at an average of 7.9 ± 3.5 months, 5 of whom returned to preinjury functional levels. Of the 8 athletes who either did not return to competitive sport or failed to sustain their high level of play, the most common reasons cited were graduation from high school or college (4 patients, 50%) or fear of reinjury (3 patients, 38%). All 4 patients citing graduation as the primary factor preventing return to preinjury level of competitive sport resumed recreational sport without limitations, yielding an adjusted RTP rate of 10 patients (77%) who either returned to competitive play or believed they could return if they had not graduated. At final follow-up, athletes reported significant improvements in all PRO scores except for KOOS-Sport, WOMAC-Stiffness, and SF-12 Mental subscales. There were 3 reoperations at an average of 3.8 ± 3.3 years after the index OCA. There were no instances of graft failure.

CONCLUSIONS

OCAs provide an adjusted RTP rate of 77% for high-level adolescent athletes. Social factors may be more likely than persistent pain to prevent return to sport.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Failure of Bone Marrow Stimulation Techniques

Marrow stimulation techniques, including microfracture, are among the most commonly performed cartilage restoration procedures for symptomatic chondral defects of the knee. For the vast majority of patients, marrow stimulation results in reduced pain and improved function, providing overall satisfactory outcomes. In some cases, however, marrow stimulation fails, resulting in symptom recurrence and often, the need for repeat surgery. This review will describe the indications and outcomes of microfracture as a primary surgical treatment for focal chondral defects of the knee, identify patient and procedure-specific factors associated with poor clinical outcomes, and will discuss treatment options and their respective outcomes for patients with a failed prior microfracture surgery.

Decrease of miR-195 Promotes Chondrocytes Proliferation and Maintenance of Chondrogenic Phenotype via Targeting FGF-18 Pathway

Slow growth and rapid loss of chondrogenic phenotypes are the major problems affecting chronic cartilage lesions. The role of microRNA-195 (miR-195) and its detailed working mechanism in the fore-mentioned process remains unknown. Fibroblastic growth factor 18 (FGF-18) plays a key role in cartilage homeostasis; whether miR-195 could regulate FGF-18 and its downstream signal pathway in chondrocyte proliferation and maintenance of chondrogenic phenotypes still remains unclear. The present research shows elevated miR-195 but depressed FGF-18 expressed in joint fluid specimens of 20 patients with chronic cartilage lesions and in CH1M and CH3M chondrocytes when compared with that in joint fluid specimens without cartilage lesions and in CH1W and CH2W chondrocytes, respectively. The following loss of function test revealed that downregulation of miR-195 by transfection of miR-195 inhibitors promoted chondrocyte proliferation and expression of a type II collagen α I chain (Col2a1)/aggrecan. Through the online informatics analysis we theoretically predicted that miR-195 could bind to a FGF-18 3' untranslated region (3'UTR), also, we verified that a miR-195 could regulate the FGF-18 and its downstream pathway. The constructed dual luciferase assay further confirmed that FGF-18 was a direct target of miR-195. The executed anti-sense experiment displayed that miR-195 could regulate chondrocyte proliferation and Col2a1/aggrecan expression via the FGF-18 pathway. Finally, through an in vivo anterior cruciate ligament transection (ACLT) model, downregulation of miR-195 presented a significantly protective effect on chronic cartilage lesions. Evaluating all of the outcomes of the current research revealed that a decrease of miR-195 protected chronic cartilage lesions by promoting chondrocyte proliferation and maintenance of chondrogenic phenotypes via the targeting of the FGF-18 pathway and that the miR-195/FGF-18 axis could be a potential target in the treatment of cartilage lesions.

Patient Experiences of Recovery After Autologous Chondrocyte Implantation: A Qualitative Study

CONTEXT

The recovery process after autologous chondrocyte implantation (ACI) can be challenging for patients and clinicians alike due to significant functional limitations and a lengthy healing time. Understanding patients' experiences during the recovery process may assist clinicians in providing more individualized care.

OBJECTIVE

To explore and describe patients' experiences during the recovery process after ACI.

DESIGN

Qualitative study.

SETTING

Orthopaedic clinic.

PATIENTS OR OTHER PARTICIPANTS

Participants from a single orthopaedic practice who had undergone ACI within the previous 12 months were purposefully selected.

DATA COLLECTION AND ANALYSIS

Volunteers participated in 1-on-1 semistructured interviews to describe their recovery experiences after ACI. Data were analyzed using the process of horizontalization.

RESULTS

Seven patients (2 men, 5 women; age = 40.7 ± 7.5 years, time from surgery = 8.7 ± 4.2 months) participated. Four themes and 6 subthemes emerged from the data and suggested that the recovery process is a lengthy and emotional experience. Therapy provides optimism for the future but requires a collaborative effort among the patient, surgeon, rehabilitation provider, and patient's caregiver(s). Furthermore, patients expressed frustration that their expectations for recovery did not match the reality of the process, including greater dependence on caregivers than expected.

CONCLUSIONS

Patients' expectations should be elicited before surgery and managed throughout the recovery process. Providing preoperative patient and caregiver education and encouraging preoperative rehabilitation can assist in managing expectations. Establishing realistic goals and expectations may improve rehabilitation adherence, encourage optimism for recovery, and improve outcomes in the long term.

A conceptual framework for a sports knee injury performance profile (SKIPP) and return to activity criteria (RTAC)

Injuries to the knee, including intra-articular fractures, ligamentous ruptures, and meniscal and articular cartilage lesions, are commonplace within sports. Despite advancements in surgical techniques and enhanced rehabilitation, athletes returning to cutting, pivoting, and jumping sports after a knee injury are at greater risk of sustaining a second injury. The clinical utility of objective criteria presents a decision-making challenge to ensure athletes are fully rehabilitated and safe to return to sport. A system centered on specific indicators that can be used to develop a comprehensive profile to monitor rehabilitation progression and to establish return to activity criteria is recommended to clear athletes to begin a progressive and systematic approach to activities and sports. Integration of a sports knee injury performance profile with return to activity criteria can guide clinicians in facilitating an athlete's safe return to sport, prevention of subsequent injury, and life-long knee joint health.

Long-term results after microfracture treatment for full-thickness knee chondral lesions in athletes

PURPOSE

Microfracture is a well-established treatment procedure for chondral defects in high-demand population with good short-term results. The purpose of our study was to evaluate long-term clinical outcome of microfracture treatment in athletes with full-thickness chondral defects.

METHODS

Between 1991 and 2001, 170 patients were treated with microfracture for full-thickness knee chondral lesions at our institute and 67 of them were included in this study and prospectively followed up. Sixty-one athletes (91%) were available at final follow-up (average 15.1 years). Average lesion size was 401 ± 27 mm2. Lysholm, Tegner and International Knee Documentation Committee (IKDC) (subjective-objective) scores were utilized pre-operatively and at 2-year, 5-year and final follow-up; Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS) and Marx scores were also collected at final follow-up.

RESULTS

IKDC, Lysholm and Tegner scores increased significantly at 2 years, but gradually deteriorated at long term; however, average scores were significantly above baseline at final follow-up. Seven patients (11%) were considered as failures as they underwent another operation because of reinjury or persistent pain during the first 5 years. Pain and swelling during strenuous activities was reported only in nine patients by the end of 2 years and in 35 patients at final follow-up. Patients with smaller lesions (≤400 mm²) and younger patients (≤30 years) showed significantly better results in KOOS, VAS and Marx scores. Radiographs performed at final follow-up showed evidence of progression of osteoarthritis changes in 40% of the knees, with higher rate in older patients with large or multiple lesions (p < 0.05).

CONCLUSIONS

Microfracture when applied in young patients with smaller lesions can offer good clinical results at short- and long-term follow-up; lesion size is more important prognostic factor of outcome than age. Deterioration of the clinical outcome should be expected after 2 and 5 years post-treatment, and degenerative changes are present at long-term follow-up, with higher rate in older athletes with large, multiple lesions.

LEVEL OF EVIDENCE

IV.

Comparison of osteochondral autologous transplantation, microfracture, or debridement techniques in articular cartilage lesions associated with anterior cruciate ligament injury: a prospective study with a 3-year follow-up

PURPOSE

To compare the concomitant treatment of articular cartilage damage in the medial femoral condyle with osteochondral autologous transplantation (OAT), microfracture, or debridement procedures at the time of anterior cruciate ligament (ACL) reconstruction.

METHODS

Between 2006 and 2009, 102 patients with a mean age of 34.1 years and with an ACL rupture and articular cartilage damage in the medial femoral condyle of the knee were randomized to undergo OAT, microfractures, or debridement at the time of ACL reconstruction. A matched control group was included, comprising 34 patients with intact articular cartilage at the time of ACL reconstruction. There were 34 patients in the OAT-ACL group, 34 in the microfracture (MF)-ACL group, 34 in the debridement (D)-ACL group, and 34 in the control group with intact articular cartilage (IAC-ACL group). The mean time from ACL injury to operation was 19.32 ± 3.43 months, and the mean follow-up was 36.1 months (range, 34 to 37 months). Patients were evaluated with the International Knee Documentation Committee (IKDC) score, Tegner activity score, and clinical assessment.

RESULTS

Of 102 patients, 97 (95%) were available for the final follow-up. According to the subjective IKDC score, all 4 groups fared significantly better at the 3-year follow-up than preoperatively (P < .005). The OAT-ACL group's IKDC subjective knee evaluation was significantly better than that of the MF-ACL group (P = .024) and D-ACL group (P = .018). However, the IKDC subjective score of the IAC-ACL group was significantly better than the OAT-ACL group's IKDC evaluation (P = .043). There was no significant difference between the MF-ACL and D-ACL groups' IKDC subjective scores (P = .058). Evaluation of manual pivot-shift knee laxity according to the IKDC knee examination form showed similar findings for the 4 groups immediately postoperatively and at 3-year follow-up, and the findings were rated as normal or nearly normal (IKDC grade A or B) in 29 of 33 patients (88%) in the OAT-ACL group, 28 of 32 patients (88%) in the MF-ACL group, 27 of 32 patients (84%) in the D-ACL group, and 31 of 34 patients (91%) in the IAC-ACL group.

CONCLUSIONS

Our study shows that intact articular cartilage during ACL reconstruction yields more favorable IKDC subjective scores compared with any other articular cartilage surgery type. However, if an articular defect is present, the subjective IKDC scores are significantly better for OAT versus microfracture or debridement after a mean period of 3 years. Anterior knee stability results were not significantly affected by the different articular cartilage treatment methods.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Return to athletic activity after osteochondral allograft transplantation in the knee

BACKGROUND

Fresh-stored osteochondral allografts have been used successfully to resurface large chondral and osteochondral defects of the knee. However, there are limited data available for the return to athletic activity.

PURPOSE

To review the rate of return to athletic activity after osteochondral allograft transplantation in the knee and to identify any potential risk factors for not returning to sport.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Forty-three athletes were treated with fresh-stored osteochondral allograft transplantation for symptomatic large chondral or osteochondral defects of the knee from 2000 to 2010. The average age of the athletes (30 men, 13 women) was 32.9 years (range, 18-49 years). Patients were prospectively evaluated by International Knee Documentation Committee (IKDC), activities of daily living scale of the Knee Injury and Osteoarthritis Outcome Score (KOOS), Marx Activity Rating Scale, and Cincinnati Sports Activity Scale scores. A multivariable regression analysis was performed to identify potential risk factors for failure to return to sport at the preinjury level.

RESULTS

At an average 2.5-year follow-up, limited return to sport was possible in 38 of 43 athletes (88%), with full return to the preinjury level achieved in 34 of 43 athletes (79%). In these 34 athletes, time to return to sport was 9.6 ± 3.0 months. Age ≥25 years (P = .04) and preoperative duration of symptoms greater than 12 months (odds ratio, 37; P = .003) negatively affected the ability to return to sport. In the athletes who returned to their previous level of competition, IKDC (P < .001), KOOS (P = .02), and Marx Activity Rating Scale (P < .001) scores were all significantly greater than in those athletes who did not return to sport.

CONCLUSION

Osteochondral allograft transplantation in an athletic population for chondral and osteochondral defects in the knee allows for a high rate of return to sport. Risk factors for not returning to sport included age ≥25 years and preoperative duration of symptoms ≥12 months.

Basic science and surgical treatment options for articular cartilage injuries of the knee

The complex structure of articular cartilage allows for diverse knee function throughout range of motion and weight bearing. However, disruption to the structural integrity of the articular surface can cause significant morbidity. Due to an inherently poor regenerative capacity, articular cartilage defects present a treatment challenge for physicians and therapists. For many patients, a trial of nonsurgical treatment options is paramount prior to surgical intervention. In instances of failed conservative treatment, patients can undergo an array of palliative, restorative, or reparative surgical procedures to treat these lesions. Palliative methods include debridement and lavage, while restorative techniques include marrow stimulation. For larger lesions involving subchondral bone, reparative procedures such as osteochondral grafting or autologous chondrocyte implantation are considered. Clinical success not only depends on the surgical techniques but also requires strict adherence to rehabilitation guidelines. The purpose of this article is to review the basic science of articular cartilage and to provide an overview of the procedures currently performed at our institution for patients presenting with symptomatic cartilage lesions.

Current concepts for rehabilitation and return to sport after knee articular cartilage repair in the athlete

Articular cartilage injury is observed with increasing frequency in both elite and amateur athletes and results from the significant acute and chronic joint stress associated with impact sports. Left untreated, articular cartilage defects can lead to chronic joint degeneration and athletic and functional disability. Treatment of articular cartilage defects in the athletic population presents a therapeutic challenge due to the high mechanical demands of athletic activity. Several articular cartilage repair techniques have been shown to successfully restore articular cartilage surfaces and allow athletes to return to high-impact sports. Postoperative rehabilitation is a critical component of the treatment process for athletic articular cartilage injury and should take into consideration the biology of the cartilage repair technique, cartilage defect characteristics, and each athlete's sport-specific demands to optimize functional outcome. Systematic, stepwise rehabilitation with criteria-based progression is recommended for an individualized rehabilitation of each athlete not only to achieve initial return to sport at the preinjury level but also to continue sports participation and reduce risk for reinjury or joint degeneration under the high mechanical demands of athletic activity.

Rehabilitation after Articular Cartilage Repair of the Knee in the Football (Soccer) Player

BACKGROUND

Participation in football can put both male and female players at an increased risk for knee osteoarthritis. There is a higher prevalence of focal chondral defects in the knee of athletes compared to nonathletes. The management of chondral defects in the football player is complex and multifactorial.

OBJECTIVE

The aim of this study is to provide an overview of the current strategies for rehabilitation after articular cartilage repair of the knee in the football player.

DESIGN

A review of current literature and the scientific evidence for rehabilitation after articular cartilage repair of the knee.

CONCLUSIONS

Articular cartilage repair has been shown to allow return to sport but rehabilitation timescales are lengthy. Successful rehabilitation for a return to football after articular cartilage repair of the knee requires the player to be able to accept the load of the sport. This necessitates a multidisciplinary approach to rehabilitation, especially in the transition from therapy to performance care. It should be recognized that not all players will return to football after articular cartilage repair. The evidence base for rehabilitative practice after articular cartilage repair is increasing but remains sparse in areas.

Clinical outcome after microfracture of the knee: a meta-analysis of before/after-data of controlled studies

PURPOSE

The aims of this study were to systematically review the medical literature, in order to find controlled studies about microfracture in the treatment of patients with full-thickness cartilage lesions of the knee, to statistically combine these studies in order to determine a best estimate of the average treatment effect, and to gather information to detect cartilage-specific and patient-specific factors that might have an influence on the clinical outcome.

METHODS

We searched four electronic databases for controlled clinical trials or controlled prospective observational studies. We pooled before/after-data of study arms using the term microfracture.

RESULTS

We calculated an overall best estimate of 1.106, with [0.566; 1.646] as 95% confidence interval of the mean standardized treatment effect for a representative patient population.

CONCLUSIONS

Our meta-analysis revealed a clinically relevant improvement of the postoperative clinical status as compared to the preoperative status. An increase of 22 overall KOOS points may provide a rough estimate for the mean expected treatment effect achieved by microfracturing.

Guidelines for the Design and Conduct of Clinical Studies in Knee Articular Cartilage Repair: International Cartilage Repair Society Recommendations Based on Current Scientific Evidence and Standards of Clinical Care

OBJECTIVE

To summarize current clinical research practice and develop methodological standards for objective scientific evaluation of knee cartilage repair procedures and products.

DESIGN

A comprehensive literature review was performed of high-level original studies providing information relevant for the design of clinical studies on articular cartilage repair in the knee. Analysis of cartilage repair publications and synopses of ongoing trials were used to identify important criteria for the design, reporting, and interpretation of studies in this field.

RESULTS

Current literature reflects the methodological limitations of the scientific evidence available for articular cartilage repair. However, clinical trial databases of ongoing trials document a trend suggesting improved study designs and clinical evaluation methodology. Based on the current scientific information and standards of clinical care, detailed methodological recommendations were developed for the statistical study design, patient recruitment, control group considerations, study endpoint definition, documentation of results, use of validated patient-reported outcome instruments, and inclusion and exclusion criteria for the design and conduct of scientifically sound cartilage repair study protocols. A consensus statement among the International Cartilage Repair Society (ICRS) and contributing authors experienced in clinical trial design and implementation was achieved.

CONCLUSIONS

High-quality clinical research methodology is critical for the optimal evaluation of current and new cartilage repair technologies. In addition to generally applicable principles for orthopedic study design, specific criteria and considerations apply to cartilage repair studies. Systematic application of these criteria and considerations can facilitate study designs that are scientifically rigorous, ethical, practical, and appropriate for the question(s) being addressed in any given cartilage repair research project.