Monopolar Radiofrequency Energy Research Articles

Outcomes of Mechanical Debridement and Radiofrequency Ablation in the Treatment of Chondral Defects – A Prospective Randomized Study

This study compared the clinical and biomechanical outcomes of mechanical debridement with and without monopolar radiofrequency energy in treating chondral defects. Patients who were scheduled for arthroscopic procedures (diagnostic, debridement and lavage, and meniscectomy) and consented to biomechanical cartilage stiffness testing comprised the study population. Patients were randomized into 2 groups. In group 1, 14 patients underwent mechanical debridement only, and in group 2, 15 patients underwent mechanical debridement followed by monopolar radiofrequency. Clinical status was evaluated using the International Knee Documentation Committee (IKDC) subjective knee form. In group 2, the biomechanical properties of the defective cartilage before and after treatment also were evaluated. Findings showed a trend toward improvement in mechanical stiffness of energy-treated chondral lesions. Moreover, no significant differences were found between IKDC scores at average follow-up of 16 to 19 months. The addition of radiofrequency energy, at least in the investigated form, does not add clinically significant benefits over mechanical debridement alone of chondral defects.

Impact of monopolar radiofrequency energy on subchondral bone viability.

The purpose of this study was to analyze the impact of monopolar radiofrequency energy treatment on subchondral bone viability. The femoral grooves of six chinchilla bastard rabbits were exposed bilaterally to monopolar radiofrequency energy for 2, 4 and 8 s, creating a total of 36 defects. An intravital fluorescence bone-labeling technique characterized the process of subchondral bone mineralization within the 3 months following exposure to radiofrequency energy and was analyzed by widefield epifluorescence optical sectioning microscopy using an ApoTome. After 2 s of radiofrequency energy exposure, regular fluorescence staining of the subchondral bone was evident in all samples when compared to untreated areas. The depth of osteonecrosis after 4 and 8 s of radiofrequency energy treatment averaged 126 and 942 µm at 22 days (P < .05; P < .01). The 4 s treatment group showed no osteonecrosis after 44 days whereas the depth of osteonecrosis extended from 519 µm at 44 days (P < .01), to 281 µm at 66 days (P < .01) and to 133 µm at 88 days (P < .05) after 8 s of radiofrequency energy application. Though radiofrequency energy may induce transient osteonecrosis in the superficial zone of the subchondral bone, the results of this study suggest that post-arthroscopic osteonecrosis appears to be of only modest risk given the current clinical application in humans.

Changes to articular cartilage following remote application of radiofrequency energy and with or without Cosequin therapy

To determine the short- and long-term changes in the biomechanical properties and metabolic activity of articular cartilage following the remote application of bipolar radiofrequency (bRF) and monopolar radiofrequency (mRF) energy within the rabbit stifle joint. The rabbits were randomly assigned to either Group-1 (normal rabbit food), or they were assigned to Group-2 (2% Cosequin in the diet). Each rabbit underwent bilateral stifle arthroscopy with either bRF or mRF applied to the infrapatellar fat pad for 45 seconds. Cartilage samples were collected at zero, four, and 14 weeks after surgery. Data were analyzed with a mixed model analysis of variance (ANOVA) for chondrocyte death, amount of GAG synthesis, and the equilibrium compressive modulus. A significant increase in histological damage was noted at weeks four and 14 compared to week zero. Most of the chondrocyte death noted with confocal laser microscopy (49 of 56 samples) was noted in the superficial region (outer 25%) of the articular cartilage. GAG synthesis was not significantly different between groups or devices at any time point. A significant difference was not noted in equilibrium compressive modulus throughout the study. Remote application of bRF and mRF energy lead to immediate chondrocyte death. Most of the damage was superficial hence the metabolic activity and biomechanical properties of the extracellular matrix were maintained throughout this study. Treatment with Cosequin did not prevent superficial chondrocyte death caused by the application of radiofrequency (RF) energy with in the joint.

Thermage: the nonablative radiofrequency for rejuvenation

Thermage is a noninvasive nonablative device that uses monopolar radiofrequency energy to bulk heat underlying skin while protecting the epidermis to produce skin tightening. It is used for the treatment of rhytids on the face including the periorbital region and lower face, and more recently, for off-face applications. Studies have shown that it can impart mild tightening of periorbital mid, and lower facial laxity. Other radiofrequency devices have also shown objective improvements in cellulite of the buttocks and thigh regions. Thermage is an efficacious and safe nonsurgical alternative for treating mild skin laxity.

Comparison of radiofrequency treatment and mechanical debridement of fibrillated cartilage in an equine model

To compare a radiofrequency energy (RFE) prototype probe to mechanical debridement (MD) and a commercially available RFE system used for chondroplasty in the treatment of an experimentally created partial thickness cartilage lesion in horses. The study design was experimental, randomized complete block, n=8, using fifteen mature ponies. Grade 2 to 3 cartilage lesions were prepared in both patellae. After 10 months duration, the injuries were used to study the effects of MD, a commercially available bipolar RFE device (CoVac 50; ArthroCare Corporation) and a prototype monopolar RFE device (Smith & Nephew Endoscopy). Six months after treatment the patellae were examined for chondrocyte viability and cartilage structure. Mean depth of cell death was significantly different among groups (controls, MD <prototype<CoVac 50) (P<0.05). Total histologic scores did not demonstrate any significant differences among the controls, MD and prototype RFE groups, which were all better than the CoVac 50 scores (P<0.05). There was a trend for the prototype RFE probe treated regions to have better surface structural characteristics than MD (P=0.11). Cartilage thickness was greater for the prototype RFE group than all other groups, and was the thinnest for the CoVac 50 group (P<0.05). When thermal chondroplasty is performed with a power-controlled prototype RFE probe, there is a better surface smoothing effect compared to MD, which causes less chondrocyte death and has the potential to maintain thicker cartilage compared to the commercially available RFE system.

Histologic Evaluation of Thermal Capsulorrhaphy of Human Shoulder Joint Capsule With Monopolar Radiofrequency Energy During Short- to Long-term Follow-up

The purpose of this study was to evaluate the histologic morphology of human shoulder joint capsule after thermal capsulorrhaphy with monopolar radiofrequency energy (mRFE) during short- to long-term follow-up. This study comprised 27 patients who received an arthroscopic mRFE thermal capsulorrhaphy and 10 patients without mRFE treatment serving as the control group. Biopsy samples from 3 locations (anterior-superior, anterior-inferior, and posterior-medial) of the shoulder joint capsule were harvested from both the mRFE-treated patients and the control patients. The follow-up time for the mRFE treatment ranged from 3.5 to 62 months, which was divided into 3 groups: short, 3.5 to 12 months; medium, 14 to 25 months; and long, 31 to 62 months. The biopsy samples were analyzed via a histologic scoring system, evaluating an intact synovial layer, subsynovial edema, collagen morphology, cellularity, vascularity, and inflammatory cells. Histologic scores among each follow-up group were compared with each other and with those in the control group. There were no significant differences in the histologic categories of intact synovial layer, subsynovial edema, collagen morphology, and inflammatory cells among the control and mid- and long-term mRFE groups. The short-term mRFE group had greater increased cellularity and vascularity compared with the mid- and long-term groups, which progressively improved toward the appearance in the normal control group with time. After mRFE capsulorrhaphy, histologic analysis revealed that the mRFE-treated shoulder joint capsule had almost returned to normal, except for persistent cellularity and increased vascularity, which were present at up to 5 years after this procedure. Level III, therapeutic case-control study.

Monopolar Radiofrequency Treatment of the Eyelids

BACKGROUND Monopolar radiofrequency (RF) energy has been used to successfully accomplish noninvasive skin tightening of the face, abdomen, and extremities. Owing to concerns about injury to the eye itself, monopolar RF treatment of the eyelids has not been feasible. OBJECTIVE The objective was to evaluate the safety of a novel 0.25-cm2“shallow” treatment tip for noninvasive tightening of eyelid skin. METHODS AND MATERIALS This was a tripartite study that began with an animal model to evaluate soft tissue effects and temperature change at the ocular surface. Findings were then extrapolated to ex vivo evaluation of human eyelids and ultimately to an in vivo human eyelid safety study. RESULTS The animal studies demonstrated that the 0.25-cm2 treatment tip could be used safely on eyelids in conjunction with appropriate ocular protection. The ex vivo human eyelid studies confirmed that, at typical treatment settings, the shallow treatment tip did not produce frank eyelid injury. The in vivo human studies confirmed that, at the tested settings, the novel treatment tip did not injure the eyelids or eyes. CONCLUSION If used properly, the 0.25-cm2 treatment tip can be safely used on human eyelids.

Monopolar Radiofrequency Treatment of the Eyelids: A Safety Evaluation

Monopolar radiofrequency (RF) energy has been used to successfully accomplish noninvasive skin tightening of the face, abdomen, and extremities. Owing to concerns about injury to the eye itself, monopolar RF treatment of the eyelids has not been feasible. The objective was to evaluate the safety of a novel 0.25-cm(2)"shallow" treatment tip for noninvasive tightening of eyelid skin. This was a tripartite study that began with an animal model to evaluate soft tissue effects and temperature change at the ocular surface. Findings were then extrapolated to ex vivo evaluation of human eyelids and ultimately to an in vivo human eyelid safety study. The animal studies demonstrated that the 0.25-cm(2) treatment tip could be used safely on eyelids in conjunction with appropriate ocular protection. The ex vivo human eyelid studies confirmed that, at typical treatment settings, the shallow treatment tip did not produce frank eyelid injury. The in vivo human studies confirmed that, at the tested settings, the novel treatment tip did not injure the eyelids or eyes. If used properly, the 0.25-cm(2) treatment tip can be safely used on human eyelids.

Monopolar Radiofrequency Energy Application to the Dorsal Extensor Tendon Apparatus in a Canine Model of Tendon Injury

Monopolar Radiofrequency Energy Application to the Dorsal Extensor Tendon Apparatus in a Canine Model of Tendon Injury

The effects of radiofrequency energy probe speed and application force on chondrocyte viability

To determine the thermal effects of monopolar radiofrequency energy (mRFE) on bovine articular cartilage when it was moved at different speeds and using varying application forces. Thirty-six fresh osteochondral sections divided into two groups (18 sections/group) were used in this study. The first group was tested at three speed rates of mRFE probe (1 mm/sec, 5 mm/sec and 10 mm/sec) at a constant force (50 g) applied to the probe tip. In the second group, three application forces of the probe tip were tested (25 g, 50 g and 75 g) at a constant speed (5 mm/sec) (n = 6/test). All tests were performed using a custom-built jig to control the mRFE (Vulcan EAS) probe during a 20-mm pass on each section. After treatment, viability of osteochondral sections was determined by confocal laser microscopy (CLM) combined with vital cell staining. There were not any significant differences in cartilage thickness of tested osteochondral sections among the different speeds or forces. During the mRFE probe treatments at different speeds, CLM demonstrated that probe application at the speed of 1 mm/sec caused significantly greater chondrocyte death than at the speeds of 5 and 10 mm/sec, whereas there were no significant differences in chondrocyte death among the variable application forces (p > 0.05). This in vitro study demonstrated that RFE thermal penetration correlated most closely with probe application speed than application force for this mRFE probe. Improper use of mRFE may cause thermal injury on articular cartilage.

An Ex Vivo Thermal Chondroplasty Model: The Association of a Char-Like Layer and Underlying Cell Death

The purpose of this study was to evaluate the relation between the char-like layer observed during radiofrequency energy (RFE) treatment of cartilage and the depth of underlying cell death. Healthy adult bovine patellae were treated with a monopolar RFE probe ex vivo at generator settings of 20, 30, 40, 50, 60, 80, and 110 in cut mode. The presence or absence of a char-like layer and visual electrical discharge was noted. Treated tissue was incubated with cell viability stain, and the depth of cell death and matrix debridement was measured from confocal laser microscopy images. At generator settings of 60 and above, a char-like layer, electrical discharge, and matrix debridement were consistently observed, and the depth of cell death was significantly less (P < .05) than when these features were not observed (< or =30). Paradoxically, the least depth of cell death did not occur at the lowest generator setting in cut mode. It occurred at a generator setting of 60. An increase in impedance of the system and a decrease in current were also associated with reduced cell death. In this controlled ex vivo study formation of a char-like layer, visual electrical discharge, increased impedance, and reduced current were associated with less depth of cell death when cartilage was treated with monopolar RFE. This study suggests that a char-like layer and electrical discharge during RFE treatment of cartilage may be advantageous because, potentially, these features are associated with less depth of cell death (safety) and greater matrix debridement (efficacy).

Monopolar Radiofrequency Energy Application to the Dorsal Extensor Tendon Apparatus in a Canine Model of Tendon Injury

To evaluate the use of monopolar radiofrequency energy (MRFE) to shorten stretched dorsal extensor tendon apparatus (DETA) tissues in a canine model. Eleven adult canine forelimbs were used in this in vitro investigation. The DETA tissue was isolated between the metacarpophalangeal and proximal interphalangeal joints in the third and fourth digits of each limb. Isolated tissue was stretched in all but 2 of the digits (control group). After tissue stretching, monopular radiofrequency energy (MRFE) was applied to 18 of the digits at 1 of 3 temperatures: 50 degrees C, 60 degrees C, or 70 degrees C (stretch-treatment group). Two digits were treated identically, but MRFE was not applied (stretch-only group). Tissue length was measured before and after stretching and after treatment. Percent stretch, percent shortening, and percent original length were compared among the 3 stretch-treatment groups. All DETA specimens were examined with light microscopy. Histologic changes were apparent in the stretch-treatment and stretch-only specimens compared with controls. Percent stretch was not significantly different between groups. Percent shortening and percent original length were significantly lower and higher, respectively, in the 50 degrees C group than in the 60 degrees C and 70 degrees C stretch-treatment groups, which were not significantly different from each other. There was a significant linear correspondence between percent shortening and treatment temperature. The application of MRFE at a temperature of 60 degrees C and a power of 10 W appears to shorten stretched DETA tissue to approximately the prestretched length in an in vitro canine model. Further investigation is necessary to determine the effect of treatment on the tissue's mechanical properties.

Mechanical and Biochemical Effect of Monopolar Radiofrequency Energy on Human Articular Cartilage

Background There are growing concerns about thermal chondroplasty using radiofrequency energy to treat partial-thickness cartilage defects. However, most studies emphasize effects on chondrocyte viability, and other factors such as mechanical properties are less studied. Hypothesis Radiofrequency energy may cause significant effects on articular cartilage other than chondrocyte viability. Study Design Controlled laboratory study. Methods Human osteoarthritic cartilage samples were obtained from total knee arthroplasty, and monopolar radiofrequency energy was applied using commercially available equipment. Material properties (compressive stiffness, surface roughness, and thickness) just before and after thermal treatment were determined using ultrasound. A series of biochemical analyses were also performed after explant culture of the samples. Results The cartilage surface became smoother by radiofrequency energy, whereas cartilage stiffness or thickness was not altered significantly. Collagen fibrils, especially in the superficial layers, were converted to denatured form, whereas proteoglycan contents released in the media as well as retained in the tissue remained unchanged. The concentrations of matrix metalloproteinases (MMP-1 and MMP-2) were reduced remarkably. Conclusion Radiofrequency energy is able to create a smooth cartilage surface and reduce catabolic enzymes at the cost of collagen denaturation and chondrocyte death in the superficial layers. The stiffness of the cartilage is not changed at time zero. Clinical Relevance Further animal as well as clinical studies will be necessary to fully evaluate the long-term effects of radiofrequency energy.

Determination of Factors Influencing Tissue Effect of Thermal Chondroplasty: An Ex Vivo Investigation

Scientific investigation of thermal chondroplasty using radiofrequency energy (RFE) is confounded by multiple factors associated with the technique. Our purpose was to determine the relative importance of the following factors on tissue effect (depth of tissue debridement plus depth of underlying cell death) of thermal chondroplasty: probe design, generator power setting, speed, force, and number of passes of the probe over treated tissue. We hypothesized the relative importance of these factors would be (from most to least important) power, passes, speed, force, and design. Bovine patellae were treated using monopolar RFE. Sample size was based on a 2-level, half-factorial design. Low and high extremes of the factors tested were power setting (50 W v 110 W), passes (1 v 5), speed (3 mm/sec v 10 mm/sec), force (0.15 N v and 0.59 N), and probe design (electrode protrusion 25 microm v 125 microm). Samples were incubated with cell viability stain and examined using confocal laser microscopy to determine tissue effect. Data were analyzed using multiple regression. All factors that were tested significantly influenced tissue effect (P < .05). Power setting had the greatest effect, followed by design, speed, passes, and force. The following interactions of factors were also significant: design and force, power and passes. The optimal configuration resulting in least tissue effect was a power setting of 50 W, electrode protrusion of 25 microm, speed of 10 mm/sec, 1 pass, and 0.15 N of applied force during treatment, which resulted in a predicted tissue effect of 99 +/- 15 microm. The least tissue effect of thermal chondroplasty was achieved with lower power using a probe with minimal electrode protrusion while performing a rapid, single, lower force pass of the probe over treated tissue. Power and probe design have the greatest influence among the factors tested; selecting these parameters preoperatively could control tissue effect.

In vivo study on the short-term effect of radiofrequency energy on chondromalacic patellar cartilage and its correlation with calcified cartilage pathology in an equine model

Chondromalacia can cause joint pain and synovial effusion with the potential for developing into osteoarthritis. Thermal chondroplasty using radiofrequency energy (RFE) has been reported to be superior to mechanical debridement for treating chondromalacia. We compared short-term changes in biomechanical properties of articular cartilage after treatment with monopolar (mRFE) or bipolar RFE (bRFE) or mechanical debridement (MD) on experimentally created grade II chondromalacia patellae. Chondromalacia patellae was created arthroscopically in both patellae of 15 ponies. Ten months after surgery, each patella was randomly assigned to one of four experimental groups: sham operated, untreated control; MD; bRFE; and mRFE. Animals were euthanized 6 months after treatment and fresh osteochondral sections were collected from the treated area, the border of the chondromalacic and nonchondromalacic area, and from two untreated areas for analysis of mechanical properties. The same areas were harvested from an additional six untreated ponies. The aggregate modulus (H(A)), Poisson's ratio (nu(s)), and permeability (k) were determined for each area under creep indentation, and cartilage thickness was measured with a needle probe. The relation between zone of calcified cartilage (ZCC) and mechanical properties of hyaline cartilage (HC) was assessed histomorphometrically. Treated areas of all four groups had inferior mechanical properties compared at the same location. The treated and border areas had significantly lower H(A) values than the untreated areas. Permeability values showed significant differences between bRFE and other treated groups. Chondromalacic areas showed thinning of cartilage compared to nonchondromalacic areas. Biomechanical properties of the injured cartilage were inferior to nonchondromalacic cartilage regardless of the treatment type. mRFE had the highest stiffness value compared to other treatments and significantly higher values than MD. A significant correlation was observed between the mechanical properties of HC and ZCC thickness.

Monopolar radiofrequency treatment of human eyelids: A prospective, multicenter, efficacy trial

To evaluate the efficacy of a novel 0.25 cm(2) monopolar radiofrequency (RF) treatment tip for aesthetic rejuvenation of the eyelids. This was a prospective, multicenter trial in which the eyelids of 72 patients were treated. Patients underwent a single treatment session and were then followed on a serial basis for 6 months. Cutaneous anesthesia was not required to perform the treatments. Assessments were made by the treating physician, the subjects, and by masked physician observers evaluating photographs taken at each data point. Upper eyelid tightening and reduction of hooding was noted in 88 and 86% of subjects, respectively. Lower eyelid tightening was noted in 71-74% of subjects. The majority of patients treated achieved at least up to 25% improvement while a smaller percentage achieved more dramatic results. There was no correlation between the amount of energy applied to the eyelids and the clinical outcome. There were no serious adverse sequelae. Human eyelids can be safely treated with monopolar RF energy delivered via a novel 0.25 cm(2) treatment tip. Using this technology non-invasive eyelid rejuvenation was achieved in the majority of subjects treated. The factors differentiating those patients who achieve the most impressive changes from others remain unclear. Further development and testing of this technology is warranted.

Monopolar Radiofrequency Treatment of Partial-Thickness Cartilage Defects in the Sheep Knee Joint Leads to Extended Cartilage Injury

Background The application of radiofrequency energy to smooth and stabilize the cartilage surface has become increasingly controversial. There is little knowledge on extended-term effects, such as cartilage viability. Purpose To analyze the effect of radiofrequency treatment on artificially created partial-thickness defects in the femoral cartilage of sheep knee joints 24 weeks after surgery. Study Design Controlled laboratory study. Methods Grade II cartilage surface defects on the medial and lateral femoral condyles were artificially created in sheep for in vivo analysis. The cartilage lesions were treated alternately on the lateral or the medial condyle using a monopolar radiofrequency probe. Radiofrequency treatment was performed in a freehand technique until surface smoothing without change of cartilage color was seen. At 24 weeks after surgery, cartilage samples were harvested and were processed for macroscopic and histological evaluation. To analyze the effect of radiofrequency at time zero, samples of sheep femoral condyle cartilage with and without artificially created clefts were treated in vitro with radiofrequency. Evaluation was performed by scanning electron and confocal microscopy. Results At 24 weeks after surgery, grade IV cartilage defects were detected in all radiofrequency-treated samples. The histological findings showed a central ulcer and dead chondrocytes in the radiofrequency-treated regions. The radiofrequency-treated cartilage revealed partial surface irregularities with partial-defect repair. After radiofrequency treatment in vitro, samples at time zero showed smoothing of the artificially created clefts, as seen by scanning electron microscopy. Confocal microscopy showed necrosis of chondrocytes over approximately one fourth of the upper cartilage thickness. Conclusion Even if chondrocyte death is seen only in approximately one fourth of the upper cartilage layers in the sheep femur after in vitro application, radiofrequency treatment can cause damage to cartilage 24 weeks after application. Clinical Relevance Caution is recommended in the application of monopolar radiofrequency energy by visual control to partialthickness cartilage defects. Irregular fronds of chondromalacia may be unattractive but represent viable articular cartilage. Using radiofrequency to obtain a more visually pleasing smooth surface may be counterproductive.

The Effect of Radiofrequency Energy on Nonweight-Bearing Areas of Bone Following Shoulder and Knee Arthroscopy

This prospective randomized clinical trial evaluated whether the use of radiofrequency energy (RFE) devices for soft-tissue ablation and coagulation cause thermal injury to bone. Fifty patients underwent one of three treatment modalities: electrocautery, monopolar RFE, or bipolar RFE. Preoperative and postoperative magnetic resonance imaging was compared to evaluate for evidence of osteonecrosis. Postoperative MRI of all patients did not reveal any osteonecrosis or subchondral edema. These findings indicate electrocautery, monopolar RFE, and bipolar RFE devices can be used safely for soft-tissue blation and hemostasis.

Thermal Energy in the Knee

ABSTRACT The use of monopolar and bipolar radiofrequency energy has become increasingly popular in the treatment of chondromalacia of the knee. Several in vitro studies have shown that radiofrequency energy application to cartilage can rapidly contour and smooth fine fibrillations associated with chondromalacia. However, confocal laser microscopy and cell viability staining have confirmed a zone of chondrocyte death after thermal chondroplasty. In vitro studies have shown that the amount of cell death is a function of many variables including the type of probe, surgical technique, and lavage solution temperature. The depth of chondrocyte death has been shown to be less with monopolar radiofrequency energy than with bipolar radiofrequency energy, but its clinical benefit remains unproven. Although chondrocytes have some ability to rebound from initial thermal trauma, radiofrequency energy should be used with care until well-designed short- and long-term clinical trials can confirm the safety and efficacy of thermal chondroplasty. The procedure itself is technically easy to perform and is largely operator dependent. Successful outcomes may depend on properly defining the indications and understanding the risks and benefits of radiofrequency energy.

Thermal profile of radiofrequency energy in the inferior glenohumeral ligament.

Currently, two different methods of applying radiofrequency (RF) energy (monopolar and bipolar) are available to the surgeon for thermal shortening of the shoulder capsule. The objective of this study was to investigate the temperature changes and the thermal conduction across the human inferior glenohumeral ligament (IGHL) during radiofrequency energy application. Thermistors were secured onto both the intra-articular and extra-articular surfaces of human IGHL. Monopolar RF energy and bipolar RF energy were delivered to the intra-articular surface at the manufacturer's recommended settings. Pre-treatment and post-treatment ligament lengths, widths, heating times, and temperatures were measured and compared. For the monopolar devices, temperature spikes to 89 degrees C were recorded for the set temperature of 67 degrees C, averaging 77 degrees C +/- 10 degrees C. Temperatures across the ligament averaged 48 degrees C +/- 3 degrees C. For both devices, the IGHL became thicker with higher RF settings. Recorded temperatures decreased as distance increased from the point of application. Maximum temperatures occurred at least 6 to 7 seconds after cessation of energy application. The bipolar and monopolar devices had similar conduction times across the ligament, suggesting that this occurs by simple diffusion of heat. Bipolar and monopolar devices were equally efficacious for capsular shrinkage if the extent of the shortening is tightly defined. The thermal probe should not rest in one position for an extended period of time during RF energy application because, as our study showed, the monitoring of temperature or the visualization of tissue change is not efficacious for determining the end point of thermal shrinkage of the shoulder capsule.