Comparison of mechanical debridement and radiofrequency energy for chondroplasty in an in vivo equine model of partial thickness cartilage injury

Intraoperative Identification and Mosaicplasty in a Case of Femur Subchondral Osteoid Osteoma

Osteoid osteomas (OOs) are non-malignant primary bone abnormalities marked by a central nidus surrounded by reactive sclerosis. They typically manifest as aggravated nocturnal pain that responds to non-steroidal anti-inflammatory drugs (NSAIDs). These growths are most frequently found within the intracortical bone and the diaphysis of elongated bones. Within the realm of uncommon conditions, intra-articular OOs (IAOOs) exhibit distinctive presentations, often leading to postponed or inaccurate diagnoses. We present a patient with OO at the distal femur, accessible through the knee joint, which was intraoperatively identified and localized using a needle pricking technique and treated by arthrotomy and mosaicplasty.

Advances in the Treatment of Partial-Thickness Cartilage Defect

Partial-thickness cartilage defects (PTCDs) of the articular surface is the most common problem in cartilage degeneration, and also one of the main pathogenesis of osteoarthritis (OA). Due to the lack of a clear diagnosis, the symptoms are often more severe when full-thickness cartilage defect (FTCDs) is present. In contrast to FTCDs and osteochondral defects (OCDs), PTCDs does not injure the subchondral bone, there is no blood supply and bone marrow exudation, and the nearby microenvironment is unsuitable for stem cells adhesion, which completely loses the ability of self-repair. Some clinical studies have shown that partial-thickness cartilage defects is as harmful as full-thickness cartilage defects. Due to the poor effect of conservative treatment, the destructive surgical treatment is not suitable for the treatment of partial-thickness cartilage defects, and the current tissue engineering strategies are not effective, so it is urgent to develop novel strategies or treatment methods to repair PTCDs. In recent years, with the interdisciplinary development of bioscience, mechanics, material science and engineering, many discoveries have been made in the repair of PTCDs. This article reviews the current status and research progress in the treatment of PTCDs from the aspects of diagnosis and modeling of PTCDs, drug therapy, tissue transplantation repair technology and tissue engineering ("bottom-up").

Bipolar Radiofrequency Ablation Does Not Result in Full-Thickness Articular Cartilage Penetration: An Ex Vivo Bovine Investigation

Purpose

Methods

Results

Conclusions

Clinical Relevance

The Arthroscopic Application of Radiofrequency in Treatment of Articular Cartilage Lesions

Articular cartilage lesion is a common disease to be treated by arthroscopic surgery. It will eventually progress to osteoarthritis without proper management, which can affect patients’ work and daily life seriously. Although mechanical debridement and laser have been used clinically for its treatment, due to their respective drawbacks, radiofrequency has drawn increasing attention from clinicians as a new technique with more advantages. However, the safety and efficacy of radiofrequency have also been questioned. In this article, the scope of application of radiofrequency was reviewed following an introduction of its development history and mechanism, and the methods to ensure the safety and effectiveness of radiofrequency through power and temperature control were summarized.

Evaluation of equine articular cartilage degeneration after mechanical impact injury using cationic contrast-enhanced computed tomography

OBJECTIVE

Cationic agent contrast-enhanced computed tomography (cationic CECT) characterizes articular cartilage ex vivo, however, its capacity to detect post-traumatic injury is unknown. The study objectives were to correlate cationic CECT attenuation with biochemical, mechanical and histological properties of cartilage and morphologic computed tomography (CT) measures of bone, and to determine the ability of cationic CECT to distinguish subtly damaged from normal cartilage in an in vivo equine model.

DESIGN

Mechanical impact injury was initiated in equine femoropatellar joints in vivo to establish subtle cartilage degeneration with site-matched controls. Cationic CECT was performed in vivo (clinical) and postmortem (microCT). Articular cartilage was characterized by glycosaminoglycan (GAG) content, biochemical moduli and histological scores. Bone was characterized by volume density (BV/TV) and trabecular number (Tb.N.), thickness (Tb.Th.) and spacing (Tb.Sp.).

RESULTS

Cationic CECT attenuation (microCT) of cartilage correlated with GAG (r = 0.74, P < 0.0001), compressive modulus (E_eq) (r = 0.79, P < 0.0001) and safranin-O histological score (r = -0.66, P < 0.0001) of cartilage, and correlated with BV/TV (r = 0.37, P = 0.0005), Tb.N. (r = 0.39, P = 0.0003), Tb.Th. (r = 0.28, P = 0.0095) and Tb.Sp. (r = -0.44, P < 0.0001) of bone. Mean [95% CI] cationic CECT attenuation at the impact site (2215 [1987, 2443] Hounsfield Units [HUs]) was lower than site-matched controls (2836 [2490, 3182] HUs, P = 0.036). Clinical cationic CECT attenuation correlated with GAG (r = 0.23, P = 0.049), E_eq (r = 0.26, P = 0.025) and safranin-O histology score (r = -0.32, P = 0.0046).

CONCLUSIONS

Cationic CECT (microCT) reflects articular cartilage properties enabling segregation of subtly degenerated from healthy tissue and also reflects bone morphometric properties on CT. Cationic CECT is capable of characterizing articular cartilage in clinical scanners.

Intra-articular Osteoid Osteoma of the Distal Femur Treated with Osteochondral Grafting: A Report of 2 Cases

CASE

Intra-articular osteoid osteoma (IAOO) is a relatively rare entity and can pose a therapeutic challenge due to proximity to the cartilage surface. We present 2 cases of subchondral osteoid osteomata within the distal femur treated with excision and osteochondral grafting of the resultant defect.

CONCLUSIONS

Subchondral IAOO can pose a therapeutic challenge. Our patients had an effective pain relief and return to activities with this treatment strategy.

A Retrospective Study Assessing Safety and Efficacy of Bipolar Radiofrequency Ablation for Knee Chondral Lesions

OBJECTIVE

Bipolar radiofrequency (bRF) ablation is gaining popularity as a treatment modality for unstable knee chondral lesions of the knee. Limited reports of osteonecrosis and chondrolysis have been published; however, there is little data examining the safety of this treatment in larger series. This study aims to evaluate the safety and efficacy of bRF in the treatment of chondral lesions encountered during knee arthroscopy.

DESIGN

A retrospective evaluation of adverse outcomes in patients that underwent treatment of chondral lesions using bRF was undertaken. Secondary outcome measures included change in patient reported outcome scores and its correlation to patient demographics and quality of chondral and meniscal lesions using Chondropenia Severity Score.

RESULTS

Only 2.2% and 2.7% of the patients had a postoperative complication or required a reoperation, respectively. None of the complications were directly related to the use of bRF. A statistically significant difference was observed when comparing pre- and postoperative scores in all normalized categories ( P < 0.0001). No statistically significant correlation was found between change in self-reported scores and Chondropenia Severity Score.

CONCLUSION

Bipolar radiofrequency ablation is a safe modality in treatment of chondral lesions.

Concepts and challenges in the use of mesenchymal stem cells as a treatment for cartilage damage in the horse

Osteoarthritis (OA), the most common form of joint disease affecting humans and horses, is characterized by the advance and decline of cartilage and loss of function of the affected joint. The progression of OA is steadily accompanied with biochemical events, which interfere with the cytokines and proteolytic enzymes responsible for progress of the disease. Recently, regenerative therapies have been used with an assumption that mesenchymal stem cells (MSCs) possess the potential to prevent the advancement of cartilage damage and potentially regenerate the injured tissue with an ultimate goal of preventing OA. We believe that despite various challenges, the use of allogenic versus autologous MSCs in cartilage regeneration, is a major issue which can directly or indirectly affect the other factors including, the timing of implantation, dose or cell numbers for implantation, and the source of MSCs. Current knowledge reporting some of these challenges that the clinicians might face in the treatment of cartilage damage in horses are presented. In this regard we conducted two independent studies. In the first study we compared donor matched bone marrow and synovial fluid - derived equine MSCs in vitro, and showed that the SFMSCs were similar to the BMMSCs in their proliferation, expression of CD29, CD44 and CD90, but, exhibited a significantly different chondrogenesis. Additionally, 3.2-21% of all SFMSCs were positive for MHC II, whereas, BMMSCs were negative. In the second study we observed that injection of both the autologous and allogenic SFMSCs into the tarsocrural joint resulted in elevated levels of total protein and total nucleated cell counts. Further experiments to evaluate the in vivo acute or chronic response to allogenic or autologous MSCs are imperative.

A review of current concepts in radiofrequency chondroplasty

Radiofrequency (RF) chondroplasty is a promising treatment of chondral defects. The purpose of this study is to summarize current literature reporting the use of radiofrequency energy as an alternative treatment to mechanical shaving in chondroplasty. This review depicts the basic understanding of RF energy in ablating cartilage while exploring the basic science, laboratory evidence and clinical effectiveness of this form of chondroplasty. Laboratory studies have indicated that RF energy decreases inflammatory markers in the cartilage as well as providing optimal results with smoothing of chondral clefts. There have been concerns of chondrolysis due to heat damage of chondrocytes; however, this is unsubstantiated in clinical studies. These clinical trials have highlighted that RF energy is a safe and efficacious method of chondroplasty when compared to the mechanical shaving technique.

The acute effect of bipolar radiofrequency energy thermal chondroplasty on intrinsic biomechanical properties and thickness of chondromalacic human articular cartilage

Radio frequency energy (RFE) thermal chondroplasty has been a widely-utilized method of cartilage debridement in the past. Little is known regarding its effect on tissue mechanics. This study investigated the acute biomechanical effects of bipolar RFE treatment on human chondromalacic cartilage. Articular cartilage specimens were extracted (n = 50) from femoral condyle samples of patients undergoing total knee arthroplasty. Chondromalacia was graded with the Outerbridge classification system. Tissue thicknesses were measured using a needle punch test. Specimens underwent pretreatment load-relaxation testing using a spherical indenter. Bipolar RFE treatment was applied for 45 s and the indentation protocol was repeated. Structural properties were derived from the force-time data. Mechanical properties were derived using a fibril-reinforced biphasic cartilage model. Statistics were performed using repeated measures ANOVA. Cartilage thickness decreased after RFE treatment from a mean of 2.61 mm to 2.20 mm in Grade II, II-III, and III specimens (P < 0.001 each). Peak force increased after RFE treatment from a mean of 3.91 N to 4.91 N in Grade II and III specimens (P = 0.002 and P = 0.003, respectively). Equilibrium force increased after RFE treatment from a mean of 0.236 N to 0.457 N (P < 0.001 each grade). Time constant decreased after RFE treatment from a mean of 0.392 to 0.234 (P < 0.001 for each grade). Matrix modulus increased in all specimens following RFE treatment from a mean 259.12 kPa to 523.36 kPa (P < 0.001 each grade). Collagen fibril modulus decreased in Grade II and II-III specimens from 60.50 MPa to 42.04 MPa (P < 0.001 and P = 0.005, respectively). Tissue permeability decreased in Grade II and III specimens from 2.04 ∗10(-15) m(4)/Ns to 0.91 ∗10(-15) m(4)/Ns (P < 0.001 and P = 0.009, respectively). RFE treatment decreased thickness, time constant, fibril modulus, permeability, but increased peak force, equilibrium force, and matrix modulus. While resistance to shear and tension could be compromised due to removal of the superficial layer and decreased fibril modulus, RFE treatment increases matrix modulus and decreases tissue permeability which may restore the load- bearing capacity of the cartilage.

Targeted In Situ Biosynthetic Transcriptional Activation in Native Surface-Level Human Articular Chondrocytes during Lesion Stabilization

OBJECTIVE

Safe articular cartilage lesion stabilization is an important early surgical intervention advance toward mitigating articular cartilage disease burden. While short-term chondrocyte viability and chondrosupportive matrix modification have been demonstrated within tissue contiguous to targeted removal of damaged articular cartilage, longer term tissue responses require evaluation to further clarify treatment efficacy. The purpose of this study was to examine surface chondrocyte responses within contiguous tissue after lesion stabilization.

METHODS

Nonablation radiofrequency lesion stabilization of human cartilage explants obtained during knee replacement was performed for surface fibrillation. Time-dependent chondrocyte viability, nuclear morphology and cell distribution, and temporal response kinetics of matrix and chaperone gene transcription indicative of differentiated chondrocyte function were evaluated in samples at intervals to 96 hours after treatment.

RESULTS

Subadjacent surface articular cartilage chondrocytes demonstrated continued viability for 96 hours after treatment, a lack of increased nuclear fragmentation or condensation, persistent nucleic acid production during incubation reflecting cellular assembly behavior, and transcriptional up-regulation of matrix and chaperone genes indicative of retained biosynthetic differentiated cell function.

CONCLUSIONS

The results of this study provide further evidence of treatment efficacy and suggest the possibility to manipulate or induce cellular function, thereby recruiting local chondrocytes to aid lesion recovery. Early surgical intervention may be viewed as a tissue rescue, allowing articular cartilage to continue displaying biological responses appropriate to its function rather than converting to a tissue ultimately governed by the degenerative material property responses of matrix failure. Early intervention may positively impact the late changes and reduce disease burden of damaged articular cartilage.

The use of radiofrequency energy for arthroscopic chondroplasty in the knee

We present a review of the current literature surrounding the use of radiofrequency energy for arthroscopic chondroplasty in the knee. This review article summarizes basic science, clinical efficacy, and recent advances in the understanding of radiofrequency energy use for the treatment of chondral lesions. Laboratory evidence of increased mechanical stability and decreased release of inflammatory mediators associated with the use of radiofrequency energy chondroplasty is described with clinical evidence of decreased pain and increased functional scores when compared with mechanical chondroplasty. We re-examine concerns about the immediate side effects of radiofrequency energy use, including damage to local structures, in light of new potentially contradictory results, as well as the progression of techniques and probe design. However, although reported complications are few, because the quality of clinical evidence about safety and efficacy remains low, we suggest cautious and judicious use of this technology until future research has clearly defined the long-term clinical outcomes and risks.

Native Chondrocyte Viability during Cartilage Lesion Progression: Normal to Surface Fibrillation

OBJECTIVE

Early surgical intervention for articular cartilage disease is desirable before full-thickness lesions develop. As early intervention treatments are designed, native chondrocyte viability at the treatment site before intervention becomes an important parameter to consider. The purpose of this study is to evaluate native chondrocyte viability in a series of specimens demonstrating the progression of articular cartilage lesions to determine if the chondrocyte viability profile changes during the evolution of articular cartilage disease to the level of surface fibrillation.

DESIGN

Osteochondral specimens demonstrating various degrees of articular cartilage damage were obtained from patients undergoing knee total joint replacement. Three groups were created within a patient harvest based on visual and tactile cues commonly encountered during surgical intervention: group 1, visually and tactilely intact surfaces; group 2, visually intact, tactilely soft surfaces; and group 3, surface fibrillation. Confocal laser microscopy was performed following live/dead cell viability staining.

RESULTS

Groups 1 to 3 demonstrated viable chondrocytes in all specimens, even within the fibrillated portions of articular cartilage, with little to no evidence of dead chondrocytes. Chondrocyte viability profile in articular cartilage does not appear to change as disease lesion progresses from normal to surface fibrillation.

CONCLUSIONS

Fibrillated partial-thickness articular cartilage lesions are a good therapeutic target for early intervention. These lesions retain a high profile of viable chondrocytes and are readily diagnosed by visual and tactile cues during surgery. Early intervention should be based on matrix failure rather than on more aggressive procedures that further corrupt the matrix and contribute to chondrocyte necrosis of contiguous untargeted cartilage.

Histopomorphic evaluation of radiofrequency mediated débridement chondroplasty

The use of radiofrequency devices has become widespread for surgical ablation procedures. When ablation devices have been deployed in treatment settings requiring tissue preservation like débridement chondroplasty, adoption has been limited due to the collateral damage caused by these devices in healthy tissue surrounding the treatment site. Ex vivo radiofrequency mediated débridement chondroplasty was performed on osteochondral specimens demonstrating surface fibrillation obtained from patients undergoing knee total joint replacement. Three radiofrequency systems designed to perform débridement chondroplasty were tested each demonstrating different energy delivery methods: monopolar ablation, bipolar ablation, and non-ablation energy. Treatment outcomes were compared with control specimens as to clinical endpoint and histopomorphic characteristics. Fibrillated cartilage was removed in all specimens; however, the residual tissue remaining at the treatment site displayed significantly different characteristics attributable to radiofrequency energy delivery method. Systems that delivered ablation-based energies caused tissue necrosis and collateral damage at the treatment site including corruption of cartilage Superficial and Transitional Zones; whereas, the non-ablation system created a smooth articular surface with Superficial Zone maintenance and without chondrocyte death or tissue necrosis. The mechanism of radiofrequency energy deposition upon tissues is particularly important in treatment settings requiring tissue preservation. Ablation-based device systems can cause a worsened state of articular cartilage from that of pre-treatment. Non-ablation energy can be successful in modifying/preconditioning tissue during débridement chondroplasty without causing collateral damage. Utilizing a non-ablation radiofrequency system provides the ability to perform successful débridement chondroplasty without causing additional articular cartilage tissue damage and may allow for other cartilage intervention success.

Radiofrequency application to the growth plate in the rabbit: a new potential approach to epiphysiodesis

BACKGROUND

Radiofrequency energy is being used more and more frequently in orthopaedics, mainly in the treatment of bone tumors. We postulated that radiofrequency ablation may produce growth plate lesions similar to those observed in the bone and conducted this study to see whether radiofrequency may be used as a technique for producing epiphysiodesis.

METHODS

We randomized 60 8-week-old female New Zealand white rabbits into 3 groups. Group A was destined for a total epiphysiodesis at 60 degrees C, group B was destined for a total epiphysiodesis at 90 degrees C, and group C for a lateral hemiepiphysiodesis at 90 degrees C. Radiofrequency energy was delivered in 1 minute in all 3 groups. Using fluoroscopic imaging, radiofrequency was applied percutaneously to the left proximal tibial physis whereas the right growth plate received a sham procedure. A bicortical pin was used to evaluate the longitudinal growth rate at every monthly radiologic control, beginning 8 weeks after the procedure. Comparisons between the right and left side and between groups A and B were achieved using a paired t test. A histopathologic study was conducted in parallel to the radiographic study.

RESULTS

In a radiograph at the 8-week point, pin migration was 4.74 mm on the left side compared with 9.72 mm on the right (P<0.0001), in group A. In group B, pin migration on the left was 1.37 mm compared with 5.49 mm on the right (P<0.0001). In group C, mean angular deviation was 11.6 degrees on the left compared with 1.9 degrees on the right (P=0.0001). These differences were maintained until the end of growth. Pathology specimens revealed cellular anarchy, loss of columnar stratification, and height of the physis on the left side, which occurred earlier and were more pronounced in group B than in group A. In group C, these changes involved only the lateral half of the left physis whereas its medial counterpart remained normal. There was no evidence of articular cartilage damage.

CONCLUSIONS

This experimental study shows that radiofrequency can efficiently and rapidly achieve epiphysiodesis. It is one of many methods that can be used for this purpose. The development of new electrodes suitable for use on human growth plates and the elaboration of specific utilization protocols may lead to its use in children. Its simplicity and precision may lead to a quick and efficient growth arrest with little pain and postoperative disability in addition to reduced costs.

CLINICAL RELEVANCE

Radiofrequency has proved to be effective in producing growth arrest in rabbits with no complications. Technical improvements and adaptations may allow its use for pediatric limb inequalities or angular deformities in the near future.

Ex vivo comparison of mechanical versus thermal chondroplasty: assessment of tissue effect at the surgical endpoint

PURPOSE

The purpose of this study was to evaluate tissue effect (tissue removal plus underlying cell death) of two chondroplasty techniques: mechanical debridement (MD) using a rotary shaver blade and thermal chondroplasty using radiofrequency energy (RFE).

METHODS

Forty-eight human chondromalacic cartilage samples were treated with either MD or RFE. Pre- and post-treatment arthroscopic images of the cartilage surface were recorded. Samples were incubated with cell viability stain and visualized with confocal laser microscopy to determine tissue effect. Smoothing was quantitated by three surgeons using a visual analog scale (VAS) as well as a subjective rating regarding whether smoothing was "arthroscopically acceptable."

RESULTS

Tissue effect at the surgical endpoint of arthroscopically acceptable smoothing was 385 microm for MD versus 236 microm for RFE, a significant difference (P < .0001). Mean post-treatment VAS for MD was 2.8 points less smooth than for RFE (P < .0001). Overall, arthroscopically acceptable smoothing was achieved in 90% of RFE samples compared to 49% of MD samples.

CONCLUSIONS

Our results shown that chondroplasty using a RFE probe results in greater smoothing of chondromalacic cartilage in fewer treatment passes and with decreased total tissue effect than MD using a rotary shaver blade.

CLINICAL RELEVANCE

If safety and efficacy can be shown in vivo, thermal chondroplasty may represent an alternative for treatment of symptomatic chondromalacia.

Mechanical chondroplasty: early metabolic consequences in vitro

PURPOSE

The purpose of this study was to determine the depth of penetration from mechanical chondroplasty and metabolic consequences of this procedure on the remaining articular cartilage.

METHODS

Mechanical chondroplasty was performed in vitro on a portion of fresh grade I or II articular cartilage from 8 human knee arthroplasty specimens. Treated and control (untreated) explants (approximately 30 mg) were cut from the cartilage. The explants were divided into 2 groups, day 1 and day 4, placed separately in a 48-well plate containing media, and incubated at 37 degrees C for 24 hours. After the 24-hour incubation, the explants were weighed on day 1 and day 4, and explant media were removed and tested for total proteoglycan synthesis and aggrecan synthesis. At time 0, 2 sets (2.6 mm each) of treated and control cartilage slices were cut with a precision saw. One set was stained for confocal laser microscopy via a cytotoxicity stain to determine cell viability. The second set was stained with H&E to determine depth of penetration.

RESULTS

The mean depth of penetration was 252.8 +/- 78 microm. There was no significant difference (P > .25) between total proteoglycan synthesis for control versus treatment groups on day 1 or 4. Aggrecan synthesis was significantly reduced on day 1 when normalized for tissue weight (P = .019) and double-stranded deoxyribonucleic acid (P = .004). On day 4, no significant difference was detected. Confocal laser microscopy did not show cell death below the zone of treatment.

CONCLUSIONS

There was no significant metabolic consequence caused by chondroplasty to the remaining articular cartilage, and the zone of injury was limited to the treatment area.

CLINICAL RELEVANCE

Mechanical chondroplasty causes no significant metabolic consequences to articular cartilage under these conditions.