The effect of radiofrequency energy on the ultrastructure of joint capsular collagen

Intra-articular temperature monitoring during radiofrequency ablation in ex-vivo bovine hip joints via Fiber Bragg grating sensors

PURPOSE

Radiofrequency ablation is an increasingly used surgical option for ablation, resection and coagulation of soft tissues in joint arthroscopy. One of the major issues of thermal ablation is the temperature monitoring across the target areas, as cellular mortality is a direct consequence of thermal dosimetry. Temperatures from 45 °C to 50 °C are at risk of damage to chondrocytes. One of the most reliable tools for temperature monitoring is represented by fiber optic sensors, as they allow accurate and real-time temperature measurement via a minimally invasive approach. The aim of this study was to determine, by fiber Bragg grating sensors (FBGs), the safety of radiofrequency ablation in tissue heating applied to ex-vivo bovine hip joints.

METHODS

Ex vivo bovine hips were subjected to radiofrequency ablation, specifically in the acetabular labrum, for a total of two experiments. The WEREWOLF System (Smith + Nephew, Watford, UK) was employed in high operating mode and in a controlled ablation way. One optical fiber embedding seven FBGs was used to record multipoint temperature variations. Each sensor was 1 mm in length with a distance from edge to edge with each other of 2 mm.

RESULTS

The maximum variation was recorded in both the tests by the FBG1 (i.e., the closest one to the electrode tip) and was lower than to 2.8 °C. The other sensors (from FBG2 to FBG7) did not record a significant temperature change throughout the duration of the experiment (maximum up to 0.7 °C for FBG7).

CONCLUSIONS

No significant increase in temperature was observed at any of the seven sites. The sensor nearest to the radiofrequency source exhibited the highest temperature rise, but the variation was only 3 °C. The minimal temperature increase registered at the measurement sites, according to existing literature, is not expected to be cytotoxic. FBGs demonstrate the potential to fulfil the strict requirements for temperature measurements during arthroscopic surgery.

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.

Electrocautery in arthroscopic surgery: intra-articular fluid temperatures above 43 °C cause potential tissue damage

PURPOSE

The use of electrocautery during arthroscopy may heat intra-articular saline and subsequently damage intra- and extra-articular tissue. Newer electrocautery devices have the ability to measure the outflow fluid temperature and switch off before reaching a certain threshold; however, the scientific evidence establishing these temperature thresholds' potential for inadvertent damage is lacking. The aim of this study was to analyse current available literature on temperature thresholds for tissue damage after exposure to heated fluid and provide a recommendation for the maximum temperature of intra-articular fluid to prevent tissue damage.

METHODS

In February 2018, a systematic literature review was performed using the MEDLINE/PubMed and Embase databases. Inclusion was limited to studies investigating temperature thresholds for thermal damage to at least one of the tissues of interest: skin, bone, cartilage, soft tissues, and nerves. Studies not reporting specific temperature thresholds for thermal damage were excluded.

RESULTS

Twenty articles were selected for the final evaluation and data extraction. Varying temperature thresholds, based on the lowest reported temperature causing tissue damage, were found for the different tissues of interest: 44 °C for dermal tissues, between 47 and 50 °C for bony tissues, 50 °C for cartilage, between 43 and 55 °C for soft tissues, and 43 °C for nerves.

CONCLUSION

Based on the current literature, a temperature threshold for intra-articular fluid of 43 °C during an arthroscopic procedure is recommended to prevent tissue damage. Higher temperatures may cause damage to surrounding intra- and extra-articular tissues. The threshold for irreversible damage is likely to be higher. In clinical practise, one should be aware of possible heating of intra-articular fluid when using electrocautery and related risk of tissue damage.

LEVEL OF EVIDENCE

III.

Arthroscopic electrothermal collagen shrinkage for partial scapholunate ligament tears, isolated or with associated triangular fibrocartilage complex injuries: a prospective study

BACKGROUND

To present the outcomes of arthroscopic electrothermal shrinkage for partial scapholunate (SL) ligament tears, isolated or with associated triangular fibrocartilage complex (TFCC) injuries.

METHODS

A prospective study of 20 patients with symptomatic instability of SL ligament (14 of them also with TFCC wrist injuries) treated with arthroscopic electrothermal shrinkage was conducted using a monopolar radiofrequency probe. No patient showed radiologic signs of static dissociation (mean SL interval 2.2 ± 0.6 mm; mean SL angle 41.4° ± 6.7°) before surgery. All patients underwent follow-up at our clinic regularly for an average of 50.6 months (range 29-80 months).

RESULTS

The modified Mayo wrist score improved from a mean of 59 ± 17.1 points preoperatively to 88.3 ± 16.2 points at the final follow-up. At the final clinical examination, a painful Watson scaphoid shift test was found in 3 patients (15%). The mean flexion-extension arc was unchanged (132° ± 19°), and mean grip strength improved 12 kg. No patient showed radiologic signs of arthritis or instability after surgery (mean SL interval 1.9 ± 0.7 mm; mean SL angle 42.7° ± 7.3°). Of the 14 patients with combined TFCC injuries, 3 patients continued complaining of ulnar-sided point tenderness. At the end of the follow-up, 80% of the subjects were satisfied or very satisfied.

CONCLUSIONS

SL ligament and TFCC electrothermal shrinkage effectively provided pain relief and grip strength increase for most of the patients treated.

LEVEL OF EVIDENCE

Level IV.

The history of radiofrequency energy and Coblation in arthroscopy: a current concepts review of its application in chondroplasty of the knee

Radiofrequency energy has had widespread use for a variety of surgical procedures. Its application in orthopedic surgery initiated with shoulder instability. Over the last couple decades it has been applied as surgical tool for cartilage treatment as well. There have been significant gains in its technology and our understanding of its potential benefits. We address its history and advancements in becoming a surgical tool for cartilage lesions along with a review of recent long-term follow up studies.

Radiofrequency-Induced Thermotherapy on Nasal Polyps: Preliminary Results

Background

The aim of this study was to determine the effects of radiofrequency-induced thermotherapy (RFITT) in patients with nasal polyps.

Methods

A retrospective analysis was performed of prospectively collected data from 17 consecutive patients (11 men and 6 women; mean age, 51.7 ± 16.9 years) treated with RFITT from 2002 to 2003. The postoperative outcome was assessed using active anterior rhinomanometry, “sniffin’ stick” test, and endoscopic nasal examination preoperatively and 4 weeks postoperatively. Subjective complaints were assessed with Likert scales.

Results

Transnasal airflow increased by 40.3% 4 weeks postoperatively (p = 0.029). Endoscopic appearance of nasal polyps indicated a nonsignificant reduction of 37.1%. Subjective complaints such as impaired nasal ventilation (p = 0.014), nasal discharge (p = 0.0007), postnasal drip (p = 0.0002), and hyposmia (p = 0.048) improved significantly 4 weeks after surgery.

Conclusion

RFITT is well tolerated as a day case procedure under local anesthesia and might be a procedure for treating recurrence of NP after sinus surgery. It remains unclear at this point whether RFITT for nasal polyps results in a permanent reduction.

ANALYTICAL SOLUTION OF HYPERBOLIC BIOHEAT EQUATION IN SPHERICAL COORDINATES APPLIED IN RADIOFREQUENCY HEATING

This paper presents an analytical solution for the hyperbolic bioheat equation in spherical coordinates under nonuniform distributed heat source term, which is theoretically modeling the Radiofrequency Heating (RFH) technique. In RFH technique a spherical electrode is inserted into the diseased tissue which leads to the heat generation there due to the imposed electromagnetic field. Because of the non-Fourier behavior of biological tissues, the hyperbolic Penne’s equation is adopted as perfused thermal model. The equation has been solved using Eigenvalue method and the closed form solutions are introduced. The temperature profiles are determined for a sample RFH procedure in cornea and liver and the effect of perfusion term in Penne’s bioheat equation is shown. The effective parameters in the RFH process such as electrode radius, power and different material are studied analytically too. The derived solution can play a role of verification basis of other numerical ones in this area.

Pelleted Bone Marrow Derived Mesenchymal Stem Cells Are Better Protected from the Deleterious Effects of Arthroscopic Heat Shock

Introduction: The impact of arthroscopic temperature on joint tissues is poorly understood and it is not known how mesenchymal stem cells (MSCs) respond to the effects of heat generated by the device during the process of arthroscopy assisted experimental cell-based therapy. In the present study, we isolated and phenotypically characterized human bone marrow mesenchymal stem cells (hBMMSCs) from osteoarthritis (OA) patients, and evaluated the effect of arthroscopic heat on cells in suspension and pellet cultures.

Methods: Primary cultures of hBMMSCs were isolated from bone marrow aspirates of OA patients and cultured using DMEM supplemented with 10% FBS and characterized for their stemness. hBMMSCs (1 × 10⁶ cells) cultured as single cell suspensions or cell pellets were exposed to an illuminated arthroscope for 10, 20, or 30 min. This was followed by analysis of cellular proliferation and heat shock related gene expression.

Results: hBMMSCs were viable and exhibited population doubling, short spindle morphology, MSC related CD surface markers expression and tri-lineage differentiation into adipocytes, chondrocytes and osteoblasts. Chondrogenic and osteogenic differentiation increased collagen production and alkaline phosphatase activity. Exposure of hBMMSCs to an illuminated arthroscope for 10, 20, or 30 min for 72 h decreased metabolic activity of the cells in suspensions (63.27% at 30 min) and increased metabolic activity in cell pellets (62.86% at 10 min and 68.57% at 20 min). hBMMSCs exposed to 37, 45, and 55°C for 120 s demonstrated significant upregulation of BAX, P53, Cyclin A2, Cyclin E1, TNF-α, and HSP70 in cell suspensions compared to cell pellets.

Conclusions: hBMMSC cell pellets are better protected from temperature alterations compared to cell suspensions. Transplantation of hBMMSCs as pellets rather than as cell suspensions to the cartilage defect site would therefore support their viability and may aid enhanced cartilage regeneration.

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.

Development of a simultaneous cryo-anchoring and radiofrequency ablation catheter for percutaneous treatment of mitral valve prolapse

Mitral valve prolapse (MVP) is one subtype of mitral valve (MV) disease and is often characterized by enlarged leaflets that are thickened and have disrupted collagen architecture. The increased surface area of myxomatous leaflets with MVP leads to mitral regurgitation, and there is need for percutaneous treatment options that avoid open-chest surgery. Radiofrequency (RF) ablation is one potential therapy in which resistive heating can be used to reduce leaflet size via collagen contracture. One challenge of using RF ablation to percutaneously treat MVP is maintaining contact between the RF ablation catheter tip and a functioning MV leaflet. To meet this challenge, we have developed a RF ablation catheter with a cryogenic anchor for attachment to leaflets in order to apply RF ablation. We demonstrate the effectiveness of the dual-energy catheter in vitro by examining changes in leaflet biaxial compliance, thermal distribution with infrared (IR) imaging, and cryogenic anchor strength. We report that 1250 J of RF energy with cryo-anchoring reduced the determinant of the deformation gradient tensor at systolic loading by 23%. IR imaging revealed distinct regions of cryo-anchoring and tissue ablation, demonstrating that the two modalities do not counteract one another. Finally, cryogenic anchor strength to the leaflet was reduced but still robust during the application of RF energy. These results indicate that a catheter having combined RF ablation and cryo-anchoring provides a novel percutaneous treatment strategy for MVP and may also be useful for other percutaneous procedures where anchored ablation would provide more precise spatial control.

Exploring channeling optimized radiofrequency energy: a review of radiofrequency history and applications in esthetic fields

INTRODUCTION

Because of its high efficiency and safety, radiofrequency (RF) energy is widely used in the dermatological field for heating biological tissue in various esthetic applications, including skin tightening, skin lifting, body contouring, and cellulite reduction. This paper reviews the literature on the use of nonablative RF energy in the esthetic field and its scientific background. The purpose of this article is to describe in detail the extensive use of medical devices based on RF technology, the development of these medical devices over the years, and recent developments and trends in RF technology.

METHODS

The authors conducted a systematic search of publications that address safety and efficacy issues, technical system specifications, and clinical techniques. Finally, the authors focused on their own clinical experiences with the use of patented Channeling Optimized RF Energy technique and mechanical massage. An in-vivo study was conducted in domestic pigs, with a thermal video camera. Twenty-seven female patients participated in a cellulite and body shaping study. The treatments were conducted according to a three-phase protocol. An additional 16 females participated in a skin tightening case study. All of the patients underwent three treatment sessions at 3-week intervals, each according to a protocol specific to the area being treated.

RESULTS

The review of the literature on RF-based systems revealed that these systems are safe, with low risks for potential side effects, and effective for cellulite, body contouring, and skin tightening procedures. The in-vivo measurements confirmed the theory that the penetration depth of RF is an inverse function of its frequency, and using a vacuum mechanism makes an additional contribution to the RF energy penetration. The heating effect of RF was also found to increase blood circulation and to induce collagen remodeling. The results from the cellulite and body shaping treatments showed an overall average improvement of 55% in the appearance of cellulite, with an average circumferential reduction of 3.31 cm in the buttocks, 2.94 cm in the thighs, and 2.14 cm in the abdomen. The results from the skin tightening procedure showed moderate improvement of skin appearance in 50% and significant improvement in 31%. At the follow-up visits the results were found to be sustained without any significant side effects.

CONCLUSION

Of all tissue heating techniques, RF-based technologies appear to be the most established and clinically proven. The design and specifications of the described vacuumassisted bipolar RF device fall within the range of the specifications currently prescribed for esthetic, nonablative RF systems.

Adoption of new technology in sports medicine: case studies of the Gore-Tex prosthetic ligament and of thermal capsulorrhaphy

Evaluation of new technology in sports medicine is supposed to promote improvements in the care of patients. It is also supposed to prohibit technology that can harm patients. This evaluation process is not perfect and at times can promote technology that not only does not help patients but may harm them. Two examples of new sports medicine technology that were widely adopted but eventually abandoned are thermal capsulorrhaphy for treatment of shoulder instability and the Gore-Tex prosthetic ligament (W. L. Gore & Associates, Flagstaff, AZ) for patients with anterior cruciate ligament deficiency. On analysis of the quick adoption of these 2 failed procedures, certain recommendations are apparent for improvement of the evaluation process. There must be a sound rationale behind any new technology, basic science research into the theory of the medical technology, and demonstrated improvements in animal models and clinical studies that are prospective cohort studies or randomized controlled trials, and finally, there must be careful follow-up and postmarket surveillance.

Clinical and histopathological results following TriPollar radiofrequency skin treatments

INTRODUCTION

Skin laxity, wrinkles and cellulite are common aesthetic problems associated with the aging process. These symptoms are due to the weakening and thinning of dermal connective tissue and the enlargement of hypodermal fat cells. The aim of this study was to evaluate the safety and efficacy of the TriPollar RF technology in reducing fat and collagen regeneration.

METHODS

Twelve healthy patients underwent weekly treatments on different body sites using the TriPollar technology. Treatment areas were photographed and measured and patient satisfaction was monitored. One abdominal patient consented to a series of TriPollar treatments prior to her scheduled abdominoplasty. A controlled histopathology analysis was performed on skin samples taken during the abdominoplasty procedure.

RESULTS

Histopathological examination revealed marked differences between treated and non-treated abdominal skin areas. An increase of 49% in dermal thickness, focal thickening of collagen fibers and focal shrinkage of fat cells was shown following TriPollar treatments. Average patient satisfaction indicated clear satisfaction with the clinical results achieved.

CONCLUSION

The TriPollar is a safe and effective non-invasive technology leading to skin tightening and body shaping. Histology results indicate changes at the dermal and fat layers following TriPollar treatments resulting in increased collagen regeneration and stimulated fat metabolism.

Electrothermal treatment of thumb basal joint instability

PURPOSE

This study examined whether radiofrequency electrothermal treatment of thumb basal joint instability could produce clinical improvement and result in successful functional outcomes for patients.

METHODS

From August 2001 to April 2006, we treated 17 thumbs with symptomatic thumb basal joint instability using arthroscopic electrothermal shrinkage of the volar ligaments and joint capsule with a monopolar radiofrequency probe. The sample included 11 men and 6 women with a mean age of 35.3 years (range, 20 to 60 years). All patients underwent regular clinical follow-up at a mean of 41 months (range, 24 to 80 months).

RESULTS

Pain improved in all thumbs after surgery. Thumb pinch strength significantly improved in all thumbs after surgery (P < .01). All patients were satisfied with the results and returned to their preinjury activities.

CONCLUSIONS

By use of the described method of arthroscopic electrothermal shrinkage of the volar ligaments and joint capsule in patients with symptomatic thumb basal joint instability, most patients had good subjective results and the pinch strength improved significantly in most patients. Of 17 thumbs, 16 had satisfactory subjective and functional stability at a minimum 2 years' follow-up.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Arthroscopic gluteal muscle contracture release with radiofrequency energy

Gluteal muscle contracture is common after repeated intramuscular injections and sometimes is sufficiently debilitating to require open surgery. We asked whether arthroscopic release of gluteal muscle contracture using radiofrequency energy would decrease complications with clinically acceptable results. We retrospectively reviewed 108 patients with bilateral gluteal muscle contractures (57 males, 51 females; mean age, 23.7 years). We used inferior, anterosuperior, and posterosuperior portals. With the patient lying laterally, we developed and enlarged a potential space between the gluteal muscle group and the subcutaneous fat using blunt dissection. Under arthroscopic guidance through the inferior portal, we débrided and removed fatty tissue overlying the contractile band of the gluteal muscle group using a motorized shaver introduced through the superior portal. Radiofrequency then was introduced through the superior portal to gradually excise the contracted bands from superior to inferior. Finally, hemostasis was ensured using radiofrequency. Patients were followed a minimum of 7 months (mean, 17.4 months; range, 7-42 months). At last followup, the adduction and flexion ranges of the hip were 45.3 degrees +/- 8.7 degrees and 110.2 degrees +/- 11.9 degrees, compared with 10.4 degrees +/- 7.2 degrees and 44.8 degrees +/- 14.1 degrees before surgery. No hip abductor contracture recurred and no patient had residual hip pain or gluteal muscle wasting. We found gluteal muscle contracture could be released effectively with radiofrequency energy.

A comprehensive review of partial anterior cruciate ligament tears

A partial tear of the anterior cruciate ligament is characterized by an asymmetric Lachman-test result, a negative pivot-shift test, a low-grade KT-1000 arthrometer measurement (< or =3 mm), and arthroscopic evidence of anterior cruciate ligament injury. The pivot shift test is the most important test in determining anterior cruciate ligament insufficiency. A positive test, independent of the grade, is indicative of a functionally deficient anterior cruciate ligament. Nonoperative management results in an acceptable clinical outcome in the majority of cases. Progression to knee instability (anterior translation and rotation) depends on the extent of the anterior cruciate ligament injury and the activity level of the patient. Thermal treatment is not recommended for partial tears of the anterior cruciate ligament. Symptomatic instability is treated reliably with anterior cruciate ligament reconstruction.

The effects of thermal capsulorrhaphy of medial parapatellar capsule on patellar lateral displacement

BACKGROUND

The effectiveness of thermal shrinkage on the medial parapatellar capsule for treating recurrent patellar dislocation is controversial. One of reasons why it is still controversial is that the effectiveness is still qualitatively measured. The purpose of this study was to quantitatively determine the immediate effectiveness of the medial parapatellar capsule shrinkage as in clinical setting.

METHODS

Nine cadaveric knees were used to collect lateral displacement data before and after medial shrinkage or open surgery. The force and displacement were recorded while a physician pressed the patella from the medial side to mimic the physical exam used in clinic. Ten healthy subjects were used to test the feasibility of the technique on patients and establish normal range of lateral displacement of the patella under a medial force. The force applied, the resulting displacement and the ratio of force over displacement were compared among four data groups (normal knees, cadaveric knees before medial shrinkage, after shrinkage and after open surgery).

RESULTS

Displacements of the cadaveric knees both before and after thermal modification were similar to normal subjects, and the applied forces were significantly higher. No significant differences were found between before and after thermal modification groups. After open surgery, displacements were reduced significantly while applied forces were significantly higher.

CONCLUSION

No immediate difference was found after thermal shrinkage of the medial parapatellar capsule. Open surgery immediately improved of the lateral stiffness of the knee capsule.

Radiofrequency remodelling of the endopelvic fascia is not an effective procedure for urodynamic stress incontinence in women

The aim of this study was to assess the efficacy and safety of transvaginal radiofrequency remodelling of the endopelvic fascia as a primary procedure for urodynamic stress incontinence due to urethral hypermobility in women. It included 24 patients who had the procedure at two district general hospitals. Outcome measures included the pad test, urodynamic assessment, continence diary, pain scores and operative as well as post-operative complications and assessment was made on recruitment during hospital admission and at 3, 6 and 12 months follow-up. A rising failure rate was noted as early as 3 months, leading to a cumulative cure rate of 45.8% at 12 months follow-up. This low effectiveness could be attributed to inherent weakness of the endopelvic fascia. No major complications were encountered and pain scores were mild.

Bipolar radiofrequency in the human meniscus. Comparative study between patients younger and older than 40 years of age

PURPOSE

To morphohistologically evaluate the effect of four increasing intensities of bipolar radiofrequency (RF) on the human meniscus and to compare the changes seen in the menisci from patients younger and older than 40 years old.

METHODS

Thirty fresh menisci were divided in two groups. Group 1: 12 menisci from patients younger than 40 y.o.; Group 2: 18 menisci from patients older than 40 y.o. Groups 1 and 2 were divided in four zones and subjected in vitro, for 3 s, to four intensities of bipolar RF energy. The samples were studied macroscopically, and microscopically.

RESULTS

Thermal changes were present between 0 and 4000 microm from the meniscal surface, with an average of 1699 microm (S.D. 740), and was significantly higher on the ablation than the coagulation group (p<0.001). We found a significant difference between the depth of thermal changes in the menisci from patients younger and older than 40 years old at medium intensities of RF energy (p=0.038 and p=0.044).

CONCLUSIONS

Although bipolar RF can cause deep thermal changes (up to 4000 microm) on the human meniscus, this effect depends on the magnitude of the energy applied. When comparing the effect between younger and older patients, the changes were deeper in the older group when RF was applied at medium intensities.

CLINICAL RELEVANCE

Based on our findings, we recommend to exert precaution when applying RF energy at medium intensities in the degenerative meniscus, due to a deeper thermal effect in this group.

Electrothermal arthroscopic shoulder capsulorrhaphy: a minimum 2-year follow-up

BACKGROUND

Few studies have documented the outcomes of thermal capsulorrhaphy for shoulder instability.

PURPOSE

To examine prospective evaluate outcomes of the first 100 patients with glenohumeral instability treated with thermal capsulorrhaphy.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 1997 and 1999, 85 of 100 patients treated with thermal capsulorrhaphy for glenohumeral instability were available for review at 2-year minimum follow-up (average, 4 years). Fifty-one patients suffered from anterior instability; 24 had an associated Bankart lesion. Ten patients demonstrated posterior instability; 1 had an associated reverse Bankart lesion. Seventeen patients had multidirectional instability; 8 had an associated Bankart lesion. Seven patients demonstrated anterior and posterior instability without an inferior component; 2 had an associated Bankart lesion. Failures were defined as shoulders requiring revision stabilization (14) or with recurrent instability (18), recalcitrant pain (3), or stiffness (2).

RESULTS

Forty-eight of 85 procedures were successful, and 37 of 85 failed. For patients with anterior instability plus a Bankart lesion, 7 of 24 (26%) had failed results. For those with anterior instability without a Bankart lesion, 10 of 27 (33%) had failed results. The failure rates for posterior, multidirectional instability, and anteroposterior were 60% (6/10), 59% (10/17), and 57% (4/7), respectively. Of the 48 successes, mean preoperative American Shoulder and Elbow Surgeons score improved from 71 to 96 postoperatively, and patient satisfaction was 9.1 on a 10-point scale.

CONCLUSION

Because of the high failure rates, we now augment thermal capsulorrhaphy with capsular plication and/or rotator interval closure in cases of posterior and multidirectional instability and have lengthened the initial immobilization period to improve outcomes. Failure rates for thermal capsulorrhaphy, even with labral repairs, are high especially for shoulders with multidirectional instability and posterior instability. When procedures were successful, however, patients were very satisfied with significant improvements in American Shoulder and Elbow Surgeons scores.

Arthroscopy of the trapeziometacarpal and metacarpophalangeal joints

Indications for small joint arthroscopy in the hand remain poorly understood. This is due to a paucity of articles discussing these techniques in the literature, as well as inadequate hands-on training in the pearls and pitfalls regarding this application within the routine "scope" of hand surgery. Despite the fact that small joint arthroscopes have been available for more than a decade, hand surgeons have been slow to adopt this technique for the treatment of both traumatic and degenerative conditions involving the thumb and the digital metacarpophalangeal joints. An arthroscopic classification for basal joint osteoarthritis provides additional clinical information and can direct further treatment depending on the stage of disease. This article will also review the brief history of trapeziometacarpal arthroscopy and provide insight as to how this technique can be incorporated into a treatment algorithm in managing this common affliction. Metacarpophalangeal joint arthroscopy is even less commonly utilized, while traumatic and overuse injuries are frequently seen in the thumb and constitute ideal indications in certain scenarios. Painful conditions affecting the metacarpophalangeal joints of the fingers are less commonly seen, yet the small joint arthroscope presents a much clearer picture of the pathology compared with other imaging techniques or even open, potentially deleterious surgery. The application of this technology to the smaller joints will soon make the treating surgeon realize that a myriad of pathologies are readily visible and can augment treatment, as well as diagnosis. Similar to the wrist, small joint arthroscopy may one day supplant imaging techniques such as magnetic resonance imaging or computed tomography for establishing an accurate diagnosis.

Effects of thermal energy on chondrocyte viability

OBJECTIVE

To determine the critical temperature that reduces chondrocyte viability and evaluate the ability of chondrocytes to recover after exposure to the critical temperature.

SAMPLE POPULATION

Cartilage explants obtained from the humeral heads of 30 sheep.

PROCEDURES

In a randomized block design, 318 full-thickness cartilage explants were collected from 30 humeral heads of sheep and cultured for up to 14 days. On the first day of culture (day 0), explants were subjected to temperatures of 37 degrees , 45 degrees , 50 degrees , 55 degrees , 60 degrees , or 65 degrees C for 5 minutes by heating culture tubes in a warming block. The ability for chondrocytes to recover after exposure to the critical temperature was determined by evaluating viability at days 0, 1, 3, 7, and 14 days after heating. Images were analyzed by use of confocal laser microscopy.

RESULTS

Analysis of images revealed a significant decrease in live cells and a significant increase in dead cells as temperature increased. Additionally, the deepest layer of cartilage had a significantly lower percentage of live cells, compared with values for the 3 most superficial layers. Chondrocytes did have some ability to recover temporarily after the initial thermal insult.

CONCLUSIONS AND CLINICAL RELEVANCE

A strong relationship exists between increasing temperature and cell death, with a sharp increase in chondrocyte death between 50 degrees and 55 degrees C. Chondrocytes in the deepest cartilage layer are most susceptible to thermal injury. The threshold of chondrocyte recovery from thermal injury is much lower than temperatures reached during chondroplasty by use of most radiofrequency energy devices.

Radiofrequency volumetric reduction for masseteric hypertrophy

Masseteric hypertrophy occurs frequently among Asians, including Koreans, because of racial characteristics and dietary habits. It is thought to be an unpleasant feature, especially because of its strong and masculine impression. Recently, the authors developed a method for the volumetric reduction of hypertrophied masseter muscles using radiofrequency energy to correct the squared facial appearance caused by the hypertrophy. This study was performed to investigate the effects of radiofrequency applied to reduce hypertrophied masseter muscles of patients who sought an aesthetic alternative for a slim, smooth, and feminine-looking lower facial contour. A total of 340 patients were treated. The patients usually recognized the volume change 3 to 6 weeks after treatment, and an objective volume reduction was observed within 3 months of the operation. The range of the reduction in the masseter thickness, as measured by ultrasonic examination at a 6-month postoperative follow-up visit, was 10% to 60% (mean, 27%). Most of the patients could eat a nearly normal diet after 4 weeks and were satisfied with the improved aesthetic contour lines of their lower face. Radiofrequency-induced coagulation tissue necrosis of the masseter did not cause any infections or limitations of mouth opening, and the clinical improvement was well maintained after the treatment.

Histologic evaluation of the glenohumeral joint capsule after radiofrequency capsular shrinkage for atraumatic instability

We evaluated histologically 10 biopsy specimens taken preoperatively from the anterior-inferior glenohumeral ligament from patients with atraumatic instability who had undergone radiofrequency capsular shrinkage, 10 taken immediately postoperatively, and 13 taken before revision. The synovial and subsynovial layers returned to normal histology in biopsy specimens taken from 6 months onwards. Collagen bundles in the fibrous layer continued to have a reparative histology during the period of the study (up to 37 months). The type of radiofrequency probe used (monopolar or bipolar) had no effect on the histologic healing process (P > 0.5, chi2 test). A histologic score was introduced, and this was found to have an excellent intraobserver agreement (weighted kappa, 0.840) and a moderate interobserver agreement (weighted kappa, 0.698).

Arthroscopie des articulations trapézométacarpienne et métacarpophalangienne : installation, voie d'abord et exploration

Indications for small joint arthroscopy in the hand remain poorly understood. This is due to a paucity of papers discussing this technique in the literature, as well as inadequate hands on training in the pearls and pitfalls regarding this application within the commonly used "scope" of arthroscopy. Despite the fact that small joint arthroscopes have been available for over a decade, hand surgeons have been slow to adopt this technique within their treatment armamentarium for the treatment of both traumatic and degenerative conditions involving the thumb and the digital metacarpophalangeal joints. A proposed arthroscopic classification for basal joint osteoarthritis provides additional clinical information and can direct further treatment depending on the stage of disease. This chapter will also review the brief history of trapeziometacarpal arthroscopy and provide insight as to how this technique can be incorporated into a treatment algorithm in managing this common affliction. Metacarpophalangeal joint arthroscopy is even less commonly used, while traumatic and overuse injuries are frequently seen in the thumb, and present an ideal indication in certain scenarios. Painful conditions affecting the metacarpophalangeal joints of the fingers are less commonly seen, yet the small joint arthroscope presents a much clearer picture of the present pathology compared to other imaging techniques or even open, and potentially deleterious, surgery. The application of this technology to the smaller joints will soon make the treating surgeon realize that a myriad of pathologies are readily visible and can augment treatment, as well as diagnosis. Similar to the wrist, small joint arthroscopy may one day supplant imaging techniques such as MRI or CT in establishing an accurate diagnosis.

Monopolar radiofrequency energy application to the dorsal extensor tendon apparatus in a canine model of tendon injury

PURPOSE

To evaluate the use of monopolar radiofrequency energy (MRFE) to shorten stretched dorsal extensor tendon apparatus (DETA) tissues in a canine model.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Ultrastructural effects of an infrared handpiece on forehead and abdominal skin

BACKGROUND

Collagen fibril contraction has been shown to be associated with tissue tightening by nonablative skin rejuvenation. Transmission electron microscopy has proven to be an effective method for characterizing collagen contraction delivered by ablative and nonablative devices used on human skin.

OBJECTIVE

The purpose of this two-part study was to evaluate ultrastructural changes in cadaveric forehead skin and live abdominal skin by transmission electron microscopy for different fluence levels using the Titan infrared handpiece (Cutera, Inc., Brisbane, CA). This device is a noncoherent selectively filtered infrared device operating in the 1,100- to 1,800-nm bandwidth, intended to provide dermal heating.

METHODS AND MATERIALS

Cadaveric forehead skin at 37 degrees C was treated with a 1x1.5-cm spot at fluences of 50 and 100 J/cm2. Informed consent was obtained and abdominal skin of one patient (before abdominoplasty) was treated in vivo with a 1x1.5-cm spot at fluences of 30, 45, and 65 J/cm2. Punch biopsies of the treatment areas and a control area were obtained immediately after treatment. Transmission electron microscopy at depths of 0 to 1 and 1 to 2 mm was performed for each biopsy to evaluate morphologic alterations of collagen fibrils in treated areas compared to the control area.

RESULTS

In the cadaveric forehead skin samples, the collagen fibril alteration was greatest in the depth range of 1 to 2 mm for both fluence settings. In the abdominal skin samples, collagen fibril alteration was not seen in the control site but was observed at all treatment levels at both the 0 to 1 and the 1 to 2-mm depths, with the least alteration seen at the shallow depth and the lowest fluence.

CONCLUSIONS

Our findings suggest that collagen fibril denaturation, consistent with fibril thermocontraction, occurs immediately after infrared tissue tightening. Collagen denaturation occurs at a depth range appropriate for deep dermal treatments. The peak in collagen fibril alteration at 1 to 2 mm is consistent with contact cooling protecting the more superficial layers of the skin.

Trapeziometacarpal arthroscopy: a classification and treatment algorithm

Arthroscopic assessment of the CMC joint allows direct visualization of all components of the joint, including synovium, articular surfaces, ligaments, and the joint capsule. It also allows for the extent of joint pathology to be evaluated and staged with intraoperative management decisions made based on this information. The author recommends this arthroscopic staging to ensure better judgment of this condition in order to provide the most adequate treatment option to patients who have this disabling condition. Future studies assessing the clinical long term results using arthroscopy will likely ensure its place in the treatment armamentarium for trapeziometacarpal osteoarthritis.

Monopolar radiofrequency electrothermal shrinkage of the scapholunate ligament

PURPOSE

This study examined whether radiofrequency electrothermal shrinkage has a role in the treatment of patients with symptomatic dynamic and predynamic scapholunate (SL) instability without advanced degenerative changes.

METHODS

From January 1999 to July 2001, 19 wrists with laxity of the SL ligament, but with symptomatic instability, were treated with arthroscopic electrothermal shrinkage of the SL ligament using a monopolar radiofrequency probe. Before surgery, all patients underwent wrist arthroscopy to confirm the diagnosis and exclude arthritis. The sample included 16 men and 3 women with an average age of 23.3 years (range, 18 to 27 years). The average time from injury to operation was 17.2 months (range, 14 to 28 months). All patients underwent follow-up at our clinic regularly for an average of 28.1 months (range, 24 to 34 months).

RESULTS

All 19 patients had attenuation or laxity of the continuity SL ligament in the radiocarpal joint. Modified Mayo wrist scores revealed the following functionality: the total arc of wrist motion in the flexion-extension plane loss averaged 5.1 degrees (P > .01). Grip force improved significantly, with 14.7% improvement of that on the normal side (P < .01). The Wilcoxon signed-rank test was used to compare the results: the postoperative scores were significantly better than the preoperative scores (P < .01). Fifteen patients (79%) were fully satisfied with the results and returned to their preinjury activity. Four patients (21%) had recurrent laxity of the SL joint.

CONCLUSIONS

Electrothermal shrinkage of the SL ligament in patients with symptomatic, predynamic and dynamic SL instability had a 79% success rate at a minimum of 2 years' follow-up.

LEVEL OF EVIDENCE

Level IV, case series.

A multi-centre randomized controlled trial comparing electrothermal arthroscopic capsulorrhaphy versus open inferior capsular shift for patients with shoulder instability: protocol implementation and interim performance: lessons learned from conducting a multi-centre RCT [ISRCTN68224911; NCT00251160]

BACKGROUND

The shoulder is the most frequently dislocated joint in the body. Multiple causes and pathologies account for the various types of shoulder instability. Multi-directional instability (MDI) and multi-directional laxity with antero-inferior instability (MDL-AII) are similar in pathology, less common and more difficult to treat. These instabilities are caused by ligamentous capsular redundancy. When non-operative management fails for these patients, quality of life is significantly impaired and surgical treatment is required to tighten the ligaments and joint capsule. The current reference (gold) standard treatment for MDI/MDL-AII is an open inferior capsular shift (ICS) surgical procedure. An alternative treatment involves arthroscopic thermal shrinkage of redundant capsular tissue to tighten the joint. However, there is a lack of scientific evidence to support the use of this technique called, electrothermal arthroscopic capsulorrhaphy (ETAC). This trial will compare the effectiveness of ETAC to open ICS in patients with MDI and MDL-AII, using patient-based quality of life outcome assessments.

METHODS

This study is a multi-centre randomized clinical trial with a calculated sample size of 58 patients (p = 0.05, 80% power). Eligible patients are clinically diagnosed with MDI or MDL-AII and have failed standardized non-operative management. A diagnostic shoulder arthroscopy is performed to confirm eligibility, followed by intra-operative randomization to the ETAC or ICS surgical procedure. The primary outcome is the disease-specific quality of life questionnaire (Western Ontario Shoulder Instability Index), measured at baseline, 3, 6, 12 and 24 months. Secondary outcomes include shoulder-specific measures (American Shoulder and Elbow Surgeons Score and Constant Score). Other outcomes include recurrent instability, complications and operative time. The outcome measurements will be compared on an intention-to-treat basis, using two-sample independent t-tests to assess statistical significance. A Generalized Estimated Equations (GEE) analysis will determine whether there is an effect over time.

DISCUSSION

This ongoing trial has encountered unexpected operational and practical issues, including slow patient enrollment due to high intra-operative exclusion rates. However, the authors have a greater understanding of multi-directional laxity in the shoulder and anticipate the results of this trial will provide the medical community with the best scientific clinical evidence on the efficacy of ETAC compared to open ICS.

Ultrastructural evaluation of multiple pass low energy versus single pass high energy radio-frequency treatment

BACKGROUND AND OBJECTIVE

The radio-frequency (RF) device is a system capable of volumetric heating of the mid to deep dermis and selective heating of the fibrous septa strands and fascia layer. Clinically, these effects promote dermal collagen production, and tightening of these deep subcutaneous structures. A new technique of using multiple low energy passes has been described which results in lower patient discomfort and fewer side effects. This technique has also been anecdotally described as giving more reproducible and reliable clinical results of tissue tightening and contouring. This study will compare ultrastructural changes in collagen between a single pass high energy versus up to five passes of a multiple pass lower energy treatment.

STUDY DESIGN/MATERIALS AND METHODS

Three subjects were consented and treated in the preauricular region with the RF device using single or multiple passes (three or five) in the same 1.5 cm(2) treatment area with a slight delay between passes to allow tissue cooling. Biopsies from each treatment region and a control biopsy were taken immediately, 24 hours or 6 months post treatment for electron microscopic examination of the 0-1 mm and 1-2 mm levels. Sections of tissue 1 mm x 1 mm x 80 nm were examined with an RCA EMU-4 Transmission Electron Microscope. Twenty sections from 6 blocks from each 1 mm depth were examined by 2 blinded observers. The morphology and degree of collagen change in relation to area examined was compared to the control tissue, and estimated using a quantitative scale.

RESULTS

Ultrastructural examination of tissue showed that an increased amount of collagen fibril changes with increasing passes at energies of 97 J (three passes) and 122 J (five passes), respectively. The changes seen after five multiple passes were similar to those detected after much more painful single pass high-energy treatments.

CONCLUSIONS

This ultrastructural study shows changes in collagen fibril morphology with an increased effect demonstrated at greater depths of the skin with multiple low-fluence passes and at lesser depths with single pass higher fluence settings. Findings suggest that similar collagen fibril alteration can occur with multiple pass low-energy treatments and single pulse high-energy treatments. The lower fluence multiple pass approach is associated with less patient discomfort, less side effects, and more consistent clinical results.

Injured rabbit ACL treated by radiofrequency. Effects of cyclic loading

BACKGROUND

Radiofrequency treatment is increasingly used to treat shoulder instability. Patients are asked to restrain their physical activities after this treatment but there is no precise information concerning the necessity for the restrain.

METHODS

There were two groups of ten specimens each. Treatment group specimens were stretched to subfailure injury, treated by a radiofrequency probe, and then cyclically loaded. Control group specimens were stretched to the same subfailure injury, Sham treated, and then cyclically loaded. Between each step of the experiment in both groups there was a relaxation test to examine the ligament viscoelastic properties. At the end, each ligament was stretched to failure and the load-elongation curve obtained.

FINDINGS

Relaxation forces decreased after the subfailure injury in both groups (average 76% and 81% of intact state, in treatment and control groups, respectively). In the treatment group, the relaxation forces first increased after the radiofrequency treatment (average 99% of intact state), and then decreased after the cyclic loading (average 50% of intact state). The treated ligaments failed at lower loads and smaller deformations than the controls.

INTERPRETATION

The radiofrequency treatment restored viscoelastic properties of the injured ligaments, but cyclic loading degraded these. Protection of the treated ligament is advised during the immediate post-operative period.

Suture plication, thermal shrinkage, and sclerosing agents: effects on rat patellar tendon length and biomechanical strength

BACKGROUND

Shortening or tightening of dense, collagenous tissues is often desirable in the treatment of laxity.

PURPOSE

To compare the effect of stress-protection suture, radiofrequency thermal shrinkage combined with stress-protection suture, and a 5% sodium morrhuate sclerosing injection on the length and biomechanical strength of the rat patellar tendon.

HYPOTHESIS

Sclerosing agents will increase tendon mechanical strength. Thermal shrinkage combined with stress-protection suture and stress-protection suture only will cause a short-term decrease in tendon strength. All 3 methods will produce equivalent shortening of the tendon.

STUDY DESIGN

Controlled laboratory study.

METHODS

Forty-six female retired breeder rats were split into 4 groups, each receiving 1 of the 3 aforementioned treatments plus a control group that received a saline injection. After 4 weeks' survival, the length and biomechanical properties of the patellar tendons were measured and compared to the contralateral untreated tendon.

RESULTS

Rats treated with stress-protection suture had shorter tendons. Radiofrequency thermal shrinkage combined with stress-protection suture yielded tendons that were both shorter and stronger than were the untreated contralateral tendons. The sodium morrhuate-injected tendons were stronger whereas the saline-treated tendons were weaker than were their respective untreated contralateral tendons.

CONCLUSION

Surgical stress-protection suture without radiofrequency shrinkage is most effective at shortening the length of the rat patellar tendon, whereas radiofrequency thermal shrinkage combined with stress-protection suture as well as sodium morrhuate are effective at increasing the strength of rat patellar tendons.

CLINICAL RELEVANCE

Judicious use of thermal shrinkage in combination with stress protection may improve ligament strength and decrease laxity.

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 partial-thickness 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.

Revision surgery for failed thermal capsulorrhaphy

BACKGROUND

With the failure of thermal capsulorrhaphy for shoulder instability, there have been concerns with capsular thinning and capsular necrosis affecting revision surgery.

PURPOSE

To report the findings at revision surgery for failed thermal capsulorrhaphy and to evaluate the technical effects on subsequent revision capsular plication.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Fourteen patients underwent arthroscopic evaluation and open reconstruction for a failed thermal capsulorrhaphy. The cause of the failure, the quality of the capsule, and the ability to suture the capsule were recorded. The patients were evaluated at follow-up for failure, which was defined as recurrent subluxations or dislocations.

RESULTS

The origin of the instability was traumatic (n = 6) or atraumatic (n = 8). At revision surgery in the traumatic group, 4 patients sustained failure of the Bankart repair with capsular laxity, and the others experienced capsular laxity alone. In the atraumatic group, all patients experienced capsular laxity as the cause of failure. Of the 14 patients, the capsule quality was judged to be thin in 5 patients and ablated in 1 patient. A glenoid-based capsular shift could be accomplished in all 14 patients. At follow-up (mean, 35.4 months; range, 22 to 48 months), 1 patient underwent revision surgery and 1 patient had a subluxation, resulting in a failure rate of 14%.

CONCLUSIONS

Recurrent capsular laxity after failed thermal capsular shrinkage is common and frequently associated with capsular thinning. In most instances, the capsule quality does not appear to technically affect the revision procedure.

Thermal modification of the lax anterior cruciate ligament using radiofrequency: efficacy or catastrophe?

Alchemists dream of using energy to turn base metal to gold. "Shrinkers" use energy to transform laxity to stability. While alchemists search for the mechanism to achieve their goal, shrinkers have thermal energy (heat) and scientific ground for their pursuit. Without doubt, application of heat to collagen using radiofrequency (RF) results in tissue shrinkage. However, with regard to thermal shrinkage of a lax anterior cruciate ligament (ACL) or ACL graft, indications and techniques, rehabilitation and outcomes require review. Such is the purpose of this article.

Treatment of glenohumeral subluxation using electrothermal capsulorrhaphy

PURPOSE

The purpose of this study was to review the results of a relatively homogenous group of patients with glenohumeral subluxation without labral pathology who were treated with an electrothermal capsulorrhaphy procedure.

TYPE OF STUDY

Case series without controls.

METHODS

From 1997 to 1998, 42 patients underwent electrothermal capsulorrhaphy using a monopolar radiofrequency probe (Oratec Interventions, Menlo Park, CA). Patients with prior capsular repairs, labral pathology that required repair, or capsular avulsion injuries were excluded from the study. Thirty-one patients met the inclusion criteria. Patients had a minimum of 2 years of follow-up (mean, 25 months), and a mean age of 25 years (range, 16 to 38 years). All of the patients had previously failed conservative treatment. There were 25 patients with unidirectional anterior instability, 2 patients with unidirectional inferior instability, 1 patient with unidirectional posterior instability, and 3 patients with multidirectional instability. The patients were assessed using a modified American Shoulder and Elbow Surgeons (ASES) score that examined pain (30 points), function (60 points), and patient satisfaction (10 points). In addition, subjective stability was assessed using a 10-point scale.

RESULTS

The average modified ASES score increased to 88 points from 56 preoperatively (P < .01). The average subjective stability scale increased to 8.5 from 4.4 preoperatively (P < .01). Nineteen patients (61%) had an excellent result, 4 (13%) had a good result, 5 (16%) had a fair result, and 3 (10%) had a poor result; 22 of 26 patients who participated in sports were able to return to their preinjury level of play. The subset of patients with isolated anterior instability had results similar to the overall group. There were no instances of axillary neuritis or other neurologic injury.

CONCLUSIONS

In carefully selected patients with shoulder instability, including unidirectional anterior instability without associated labral pathology, electrothermal capsulorrhaphy was effective and had few complications.

LEVEL OF EVIDENCE

Level IV, case series without controls.

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.

Excessive radiofrequency application: effects on capsular tissue in an animal model

Capsular attenuation has been seen after thermal capsulorrhaphy surgery. The purpose of this study was to evaluate the mechanical, histologic, and morphologic effects on capsular tissue after cumulative applications of radiofrequency energy. Ovine patellofemoral capsular tissue was treated with 1, 2, 4, or 8 applications of bipolar radiofrequency energy and then analyzed. No acute capsular ablation or destruction was seen grossly, even in the 8-application group. No definitive visual clues that excessive radiofrequency energy had been applied were seen. There was significant shrinkage and loss of tensile stiffness for all thermal application groups. Given the small sample sizes, post-application failure load, percent relaxation, and stiffness were not observed to be significantly different among the groups. Cumulative applications produced minimal further tissue shrinkage but were accompanied by larger, though not statistically significant, mechanical property losses and increased depth of tissue penetration. These findings suggest that there is no benefit to repeated applications of radiofrequency energy to capsular tissue.