The thermal properties of bovine joint capsule. The basic science of laser- and radiofrequency-induced capsular shrinkage

Management of shoulder instability in hypermobility-type Ehlers-Danlos syndrome

Shoulder instability in hypermobile Ehlers-Danlos syndrome can result in lifelong pain and functional disability. Treatment in this population is complicated by the severe degree of instability as well as the underlying abnormalities of the joint connective tissue. Appropriate care for these patients requires a thorough understanding of the natural history of their disease, knowledge of the available treatment options, and certain special considerations. This article reviews the pathoanatomy, recognition, and management of shoulder instability in the patient with hypermobile Ehlers-Danlos syndrome.

Dual-sectored transurethral ultrasound for thermal treatment of stress urinary incontinence: in silico studies in 3D anatomical models

The purpose of this study is to investigate the feasibility and performance of a stationary, non-focused dual-sectored tubular transurethral ultrasound applicator for thermal exposure of tissue regions adjacent to the urethra for treatment of stress urinary incontinence (SUI) through acoustic and biothermal simulations on 3D anatomical models. Parametric studies in a generalized tissue model over dual-sectored ultrasound applicator configurations (acoustic surface intensities, lateral active acoustic output sector angles, and durations) were performed. Selected configurations and delivery strategies were applied on 3D pelvic anatomical models. Temperature and thermal dose distributions on the target region and surrounding tissues were calculated. Endovaginal cooling was explored as a strategy to mitigate vaginal heating. The 75-90° dual-sectored transurethral tubular transducer (3.5 mm outer diameter (OD), 14 mm length, 6.5 MHz, 8.8-10.2 W/cm²) and 2-3-min sonication duration were selected from the parametric study for acoustic and biothermal simulations on anatomical models. The transurethral applicator with two opposing 75-90° active lateral tubular sectors can create two heated volumes for a total of up to 1.8 cm³ over 60 EM_43 °C, with at least 10 mm radial penetration depth, 1.2 mm urethral sparing, and no lethal damage to the vagina and adjacent bone (< 60 EM_43 °C). Endovaginal cooling can be applied to further reduce the vaginal wall exposure (< 15 EM_43 °C). Simulations on 3D anatomical models indicate that dual-sectored transurethral ultrasound applicators can selectively heat pelvic floor tissue lateral to the mid-urethra in short treatment durations, without damaging adjacent vaginal and bone tissues, as a potential alternative treatment option for stress urinary incontinence. Graphical abstract Schema for in silico investigation of transurethral ultrasound thermal therapy applicator for minimally invasive treatment of SUI.

History of surgical stabilization for posterior shoulder instability

Background

Posterior shoulder instability is common in young athletes. Although the posterior shoulder instability literature is less robust than its anterior counterpart, many surgical procedures have been developed and refined over the past several centuries to address this condition.

Materials and methods

This article represents a retrospective historical analysis of the most common procedures used to treat posterior shoulder instability after sports injuries. A systematic approach to obtain published information on posterior shoulder instability was performed using the PubMed/MEDLINE database, manual searches of high–impact factor journals, and conference proceedings and books.

Results

A wide array of both soft tissue–based and bone-based procedures have been developed for the treatment of posterior shoulder instability, ranging from procedures addressing the soft tissue alone (capsular shift, labral repair, reverse Putti-Platt) or bone-based procedures (glenoid and/or humeral osteotomy, glenoid bone block) to a combination of both bone and soft-tissue procedures (modified McLaughlin procedure).

Discussion

Over the past several centuries, a number of procedures have been developed to address posterior shoulder instability, particularly as this pathology has become better understood. Future work is required not only to continue to advance these procedures but also to assess their outcomes. An understanding of the historical perspective of posterior shoulder instability procedures is essential as surgeons continue to modify these procedures in an effort to best help their patients.

Arthroscopic Electrothermal Collagen Shrinkage for Symptomatic Laxity of the Scapholunate Interosseous Ligament

The medical records, radiographs and operative reports of ten consecutive patients of average age 37 (range 19–67) years with wrist pain secondary to structural disruption of the scapholunate interosseous ligament (Geissler Type 2 injuries) who were treated with wrist arthroscopy and electrothermal collagen shrinkage of the scapholunate interosseous ligament were reviewed. Functional outcomes were assessed using the DASH scoring system at an average follow-up of 28 (range 12–44) months. At latest follow-up, nine patients (90%) were asymptomatic and had returned to their pre-injury functional level. The mean score on the DASH questionnaire was 20 (range 11–48). One patient developed wrist discomfort and mechanical symptoms 7 months postoperatively and required revision surgery. Our preliminary findings suggest that this may be a viable treatment option in the management of patients with symptomatic scapholunate interosseous ligament laxity without complete ligament disruption. Additional study is needed to better understand the role of this treatment modality.

Radiofrequency for the treatment of skin laxity: mith or truth

The nonablative radiofrequency is a procedure commonly used for the treatment of skin laxity from an increase in tissue temperature. The goal is to induce thermal damage to thus stimulate neocollagenesis in deep layers of the skin and subcutaneous tissue. However, many of these devices haven't been tested and their parameters are still not accepted by the scientific community. Because of this, it is necessary to review the literature regarding the physiological effects and parameters for application of radiofrequency and methodological quality and level of evidence of studies. A literature search was performed in MEDLINE, PEDro, SciELO, PubMed, LILACS and CAPES and experimental studies in humans, which used radiofrequency devices as treatment for facial or body laxity, were selected. The results showed that the main physiological effect is to stimulate collagen synthesis. There was no homogeneity between studies in relation to most of the parameters used and the methodological quality of studies and level of evidence for using radiofrequency are low. This fact complicates the determination of effective parameters for clinical use of this device in the treatment of skin laxity. The analyzed studies suggest that radiofrequency is effective, however the physiological mechanisms and the required parameters are not clear in the literature.

Outlet biceps tenodesis: a new technique for treatment of biceps long head tendon injury

Degeneration and tearing of the long head of the biceps brachii tendon (LHBT) are common intra-articular findings, and surgical intervention including tenodesis or tenotomy is beneficial. A new arthroscopic shoulder technique may be performed through an anterior portal while one is viewing from a posterior portal: (1) Visualize the intra-articular biceps tendon. (2) Identify the segment of the LHBT to be enlarged. (3) Use a tissue modulation wand to enlarge the tendon. (4) Evaluate the diameter of the enlarged segment. It should be twice the original diameter. (5) Cut the biceps tendon at the proximal end of the enlarged segment. (6) View the tendon within the tunnel. (7) Identify and cut the remaining stump of the biceps tendon. Seventeen cadaveric shoulders were used to compare the pullout force, stiffness, and displacement of outlet tenodesis versus tenotomy. There was a significant increase in pullout force for the outlet tenodesis group when compared with tenotomy. This technique is used to operatively treat LHBT intra-articular pathology in patients who would benefit from tenotomy and traditional biceps tenodesis and may minimize the retraction of the biceps tendon distally.

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.

Thermal shrinkage for shoulder instability

Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent shoulder stabilization surgery with thermal capsular shrinkage using a monopolar radiofrequency device. Follow-up included a subjective outcome questionnaire, discussion of pain, instability, and activity level. Mean follow-up was 3.3 years (range 2.0-4.7 years). The thermal capsular shrinkage procedure failed due to instability and/or pain in 31% of shoulders at a mean time of 39 months. In patients with unidirectional anterior instability and those with concomitant labral repair, the procedure proved effective. Patients with multidirectional instability had moderate success. In contrast, four of five patients with isolated posterior instability failed. Thermal capsular shrinkage has been advocated for the treatment of shoulder instability, particularly mild to moderate capsular laxity. The ease of the procedure makes it attractive. However, our retrospective review revealed an overall failure rate of 31% in 80 patients with 2-year minimum follow-up. This mid- to long-term cohort study adds to the literature lacking support for thermal capsulorrhaphy in general, particularly posterior instability.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s11420-010-9187-7) contains supplementary material, which is available to authorized users.

Glenohumeral chondrolysis: a systematic review of 100 cases from the English language literature

HYPOTHESIS

Chondrolysis can be a devastating complication of shoulder arthroscopy. We undertook a review of the 100 cases reported in the English language to test the hypothesis that common factors could be identified and that the identification of these factors could suggest strategies for avoiding this complication.

MATERIALS AND METHODS

We systematically reviewed the English language literature and identified 16 articles reporting 100 shoulders in which postsurgical glenohumeral chondrolysis had developed.

RESULTS

The average reported patient age was 27 +/- 11 years at the time of surgery; 35 were women. The most common indications for surgery were instability (n = 68) and superior labrum anteroposterior lesions (n = 17). In 59 cases, chondrolysis was reported to be associated with the use of intra-articular pain pumps. The infusate was known to include bupivacaine in 50 shoulders and lidocaine in 2. Radiofrequency capsulorrhaphy was performed in 2 shoulders.

DISCUSSION

Fifty-nine percent of the reported cases of glenohumeral chondrolysis occurred with the combination of arthroscopic surgery and postarthroscopy infusion of local anesthetic. The arthroscopic operations observed with chondrolysis were not limited to stabilization procedures, and the infused anesthetic was not limited to bupivacaine.

CONCLUSION

In that postoperative infusion of local anesthetic and radiofrequency may not be essential to the success of shoulder arthroscopy, surgeons may wish to consider the possible risks of their use.

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.

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.

Standardisation of Parameters during Endovenous Laser Therapy of Truncal Varicose Veins - Experimental Ex-vivo Study

BACKGROUND

Vein shrinkage is a surrogate marker for successful laser treatment of varicose veins. However, many controversies still remain concerning the best laser parameters to use. The aim of this study was standardisation of intraoperative energy dosages and pull-back rates to achieve optimal clinical results.

DESIGN

Ex-vivo study in surgically removed saphenous trunks.

MATERIAL AND METHODS

Great saphenous veins were removed by Babcock stripping and irradiated with laser energy delivered by a laser diode emitting at 980 nm. In total, 279 vein segments (5 cm long) were treated using powers from 5-15 W. Vein segments were opened longitudinally and the circumference measured in the treated and untreated regions to assess thermal shrinkage.

RESULTS

The greatest shrinkage and minimum number of perforations was achieved using lower or medium power (8 to 12 W) with longer exposure to administer laser energy. The median percentage vein shrinkage was 50% (power 5 W), 45% (8 W), 40% (10 W), 45% (12 W) and 59% (15 W). When a higher power was used (15 W), the perforations were more frequent and carbonisation was marked.

CONCLUSIONS

Our data suggests that similar efficacy with fewer vein perforations may be obtained with low or medium power settings and increased exposure when undertaking laser obliteration of saphenous trunks. This may result in fewer adverse events such as ecchymosis following treatment in patients.

Arthroscopic thermal capsulorrhaphy for palmar midcarpal instability

Midcarpal instability is an uncommon problem in which deficient static and dynamic wrist stabilisers cause sudden, uncontrolled movement of the proximal carpal row. We studied 15 wrists prospectively in 13 patients who underwent arthroscopic thermal capsulorrhaphy for palmar midcarpal instability. Capsulorrhaphy was performed using standard wrist arthroscopic techniques and a small diameter monopolar radiofrequency probe. One hundred percent follow-up was achieved at a mean of 42 (range 14 - 67) months. With regards to instability, all wrists showed improvement or resolution of instability. Functional improvement was confirmed by an improvement in the mean DASH score from 38 pre-operatively to 17 at final follow-up. Our early results show that thermal capsulorrhaphy is effective in reducing the instability symptoms of palmar midcarpal instability.

Glenohumeral chondrolysis after shoulder arthroscopy with thermal capsulorrhaphy

Glenohumeral chondrolysis is a rare but devastating complication that can occur after shoulder arthroscopy and thermal capsulorrhaphy. We retrospectively reviewed the medical records and imaging studies of 8 patients in whom glenohumeral chondrolysis developed after shoulder arthroscopy in which thermal energy was used. Of the 8 patients, 5 had previous thermal capsulorrhaphy for the diagnosis of instability. Two patients were diagnosed with instability with associated labral tears and underwent labral repair with thermal capsular shrinkage. One patient was diagnosed with a labral tear and underwent labral debridement with an extensive glenohumeral synovectomy via a thermal probe. No patients had evidence of chondral damage at their index arthroscopy, and none received postoperative pain pumps. In all patients, radiographic evidence of chondrolysis developed and repeat arthroscopy was performed to confirm the diagnosis. Open surgical stabilization has not been known to have this complication, and it is speculated that heating of the joint fluid at the time of arthroscopy from any source plays a role in cartilage death. Further studies are warranted to determine whether adequate outflow during shoulder arthroscopy where the fluid volume is relatively small will aid in avoiding complications associated with the use of heat sources.

Histologic changes after meniscal repair using radiofrequency energy in rabbits

PURPOSE

Our purpose was to investigate histologic changes in the rabbit meniscus after meniscal repair via radiofrequency energy (RFE).

METHODS

Twenty Japanese white rabbits underwent bilateral knee arthrotomies, and a longitudinal tear was made in the avascular area of both medial menisci. On the right knees, RFE treatment (60 degrees C and 40 W) was performed on the femoral surface of the meniscal tear in monopolar mode. On the left knees, the meniscus was left untreated as a control. The rabbits were killed at 0, 1, 2, 4, or 12 weeks after surgery, and all medial menisci were examined histologically. The expression of autocrine motility factor in meniscal fibrochondrocytes was examined by immunohistochemical analysis.

RESULTS

Histologic examination at baseline showed fusion of collagen fibers in the tear. Failure of fusion was found in 2 of 4 menisci at 2 weeks and 1 of 4 menisci at 4 and 12 weeks. One week after surgery, the specimens showed an acellular area as a result of fibrochondrocyte death. The acellular area expanded deeper until 4 weeks and was reduced at 12 weeks. On the femoral surface of the RFE-treated area, fibroblast proliferation was found at 2 weeks, and fibroblasts had invaded into the meniscus tissue from the meniscal surface at 12 weeks. Immunohistochemical analysis showed that the expression of autocrine motility factor in RFE-treated menisci was significantly higher than that in control menisci from 1 to 12 weeks.

CONCLUSIONS

RFE treatment at 60 degrees C and 40 W fused the collagen fiber in the meniscal tear in rabbits just after surgery. After RFE treatment, an acellular area developed as a result of fibrochondrocyte damage. RFE caused fibroblast proliferation at 2 weeks. The acellular area was reduced by cell repopulation at 12 weeks.

CLINICAL RELEVANCE

RFE may induce fibroblast proliferation for meniscal repair.

A preclinical study of nonsurgical radiofrequency collagen remodeling for the treatment of stress urinary incontinence

Many women with stress urinary incontinence seek a nonsurgical, well-tolerated, effective and durable treatment that is associated with a rapid recovery and improvement in quality of life. However, the nonsurgical options available, such as pelvic floor exercises or behavioral therapy, are typically not effective; thus, many women with the condition remain untreated. A new nonsurgical treatment, transurethral radiofrequency collagen remodeling, offers many patient-desired treatment characteristics. This prospective, controlled animal study was performed to evaluate the safety, gross and histological impact, and physiological effect of transurethral radiofrequency collagen remodeling. The outcomes served as the basis for initial and subsequent clinical trials in women.

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.

Fluid temperatures during radiofrequency use in shoulder arthroscopy: a cadaveric study

Cadaveric shoulders underwent thermal capsulorrhaphy and subacromial decompression with 3 different commercially available radiofrequency (RF) devices to evaluate local and regional fluid temperatures while arthroscopic procedures were being performed. Fifteen completely thawed fresh-frozen shoulders underwent both thermal capsulorrhaphy and subacromial decompression. During thermal capsulorrhaphy, Fluoroptic mini-thermometer probes (Luxtron model 3000) were placed in the inflow bag; in the glenohumeral joint, near the inferior glenohumeral ligament; and on the RF wand. During subacromial decompression, the temperature probes were placed in the anterior and posterior subacromial space, as well as in the inflow bag and on the RF wand. All data were initially analyzed by use of analysis of variance, followed by pairwise comparison, adjusted for multiple testing by use of the Scheffé method. Mean fluid temperatures (in degrees Celsius [+/- SD]) were highest at the RF wand during both capsulorrhaphy and subacromial decompression. Mean fluid temperatures were much lower at other recorded sites. In this model, we show no deleterious elevation in arthroscopic fluid temperature while performing thermal capsulorrhaphy or subacromial decompression using any of the 3 devices at their recommended settings.

Thermal capsulorrhaphy for the treatment of shoulder instability

Thermal capsulorrhaphy has been used to treat many different types of shoulder instability, including multidirectional instability, unidirectional instability, and microinstability in overhead-throwing athletes. A device that delivers laser energy or radiofrequency energy to the capsule tissue causes the collagen to denature and the capsule to shrink. The optimal temperature to achieve the most shrinkage without causing necrosis of the tissue is between 65 degrees and 75 degrees centigrade. This treatment causes a significant decrease in mechanical stiffness for the first 2 weeks, and then, after the tissue undergoes active cellular repair from the surrounding uninjured tissue, the mechanical properties return to near normal by 12 weeks. If the thermal energy is applied in a grid pattern, then the tissue heals with more stiffness by 6 weeks. Clinical studies on thermal capsulorrhaphy for the treatment of multidirectional instability have shown a high rate of recurrent instability (12%-64%). The clinical studies on unidirectional instability showed much better recurrence rates (4%-25%), but because most of the patients also underwent concomitant Bankart repairs and superior labral anterior posterior lesion repairs, the efficacy of the thermal treatment cannot be ascertained. A randomized controlled trial would be needed to assess whether instability with Bankart lesions requires augmentation with thermal capsulorrhaphy. For the patients with microinstability who are overhead-throwing athletes, thermal capsulorrhaphy has shown varying results from a 97% rate of return to sports to a 62% rate of return to sports. Complications of this technique include temporary nerve injuries that usually involve the sensory branch of the axillary nerve and thermal necrosis of the capsule, which is rare.

Prediction of heat-induced collagen shrinkage by use of second harmonic generation microscopy

Collagen shrinkage associated with denaturation from thermal treatment has a number of important clinical applications. However, individualized treatment is hindered by the lack of reliable noninvasive methods to monitor the process of collagen denaturation. We investigate the serial changes of collagen denaturation from thermal treatment of rat tail tendons at 58 degrees C by use of second harmonic generation (SHG) microscopy. We find that rat tail tendon shrinks progressively from 0 to 9 min of thermal treatment, and remains unchanged in length upon further thermal treatment. The SHG intensity also decreases from 0 to 9 min of thermal treatment and becomes barely detectable from further thermal treatment. Collagen shrinkage and the SHG intensity are well correlated in a linear model. In addition, SHG imaging reveals a tiger-tail-like pattern of collagen denaturation. The bands of denatured collagen progressively widen from increased thermal treatment and completely replace the adjacent bands of normal collagen after 9 min of thermal treatment. Our results show that collagen denaturation in rat tail tendon from thermal treatment is inhomogeneous, and that SHG intensity can be used to predict the degree of thermally induced collagen shrinkage. With additional development, this approach has the potential to be used in biomedical applications.

Thermal medial retinaculum shrinkage and lateral release for the treatment of recurrent patellar instability

PURPOSE

To study a technique of medial retinacular thermal shrinkage and evaluate the clinical effectiveness of this technique.

TYPE OF STUDY

Nonrandomized prospective case series.

METHODS

A consecutive series of patients with recurrent patellar instability treated with arthroscopic lateral release and medial thermal retinaculum shrinkage using a monopolar radiofrequency probe was assessed subjectively by visual analog scale and both preoperatively and postoperatively by physical examination and Lysholm and Fulkerson knee scores.

RESULTS

We evaluated 53 knees with an average follow-up of 53 months (range, 24 to 88 months). The mean Lysholm and Fulkerson scores improved from 45 and 41 to 81 and 82, respectively. Subjectively, 48 of 53 knees (90%) were reported as excellent or good. The average visual analog scale score was 8 out of 10. Five patients failed because of recurrent dislocation (9% recurrence). Additional stabilization procedures were performed in 4 patients.

CONCLUSIONS

Medial shrinkage using monopolar thermal energy is effective in treating recurrent patellar instability. Our results were comparable with prior studies using suture plication. The technique avoids additional incisions and decreases operative time.

LEVEL OF EVIDENCE

Level IV, therapeutic prospective cohort study.

Radiofrequency energy effects on the mechanical properties of tendon and capsule

PURPOSE

To compare the mechanical properties of tendon and capsule after radiofrequency (RF) energy treatment.

TYPE OF STUDY

An in vitro study.

METHODS

RF energy was applied to ovine extensor tendon and human cadaveric glenohumeral capsule varying in the treatment wattage and time (5, 10, or 20 W for 10 or 30 seconds). The associated tissue length changes and dynamic and failure properties of the tissues were investigated using a materials testing machine.

RESULTS

Length changes in the 2 tissues were comparable across the range of treatment settings used with both increases in the treatment wattage and time increasing the amount of tissue shrinkage observed. However, tendon showed greater changes in its mechanical properties after RF treatment, with significant decreases in the failure properties of the tissue as well as the dynamic and static stiffness.

CONCLUSIONS

RF treatment shrinks collagenous tissues in a progressive manner correlated to the treatment wattage. However, it has different effects on the mechanical properties of tendon and capsule with the properties of tendinous tissues dramatically reduced.

CLINICAL RELEVANCE

RF treatment has been shown to effect the mechanical properties of different collagenous tissues differently; therefore, it must be used specifically and with caution around areas of mixed tissue origin.

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.

Chitosan adhesive for laser tissue repair: in vitro characterization

BACKGROUND AND OBJECTIVES

Laser tissue repair usually relies on hemoderivate protein solders, based on serum albumin. These solders have intrinsic limitations that impair their widespread use, such as limited tensile strength of repaired tissue, poor solder solubility, and brittleness prior to laser denaturation. Furthermore, the required activation temperature of albumin solders (between 65 and 70 degrees C) can induce significant thermal damage to tissue. In this study, we report on the design of a new polysaccharide adhesive for tissue repair that overcomes some of the shortcomings of traditional solders.

STUDY DESIGN/MATERIALS AND METHODS

Flexible and insoluble strips of chitosan adhesive (elastic modulus approximately 6.8 Mpa, surface area approximately 34 mm2, thickness approximately 20 microm) were bonded onto rectangular sections of sheep intestine using a diode laser (continuous mode, 120 +/- 10 mW, lambda = 808 nm) through a multimode optical fiber with an irradiance of approximately 15 W/cm2. The adhesive was based on chitosan and also included indocyanin green dye (IG). The temperature between tissue and adhesive was measured using a small thermocouple (diameter approximately 0.25 mm) during laser irradiation. The repaired tissue was tested for tensile strength by a calibrated tensiometer. Murine fibroblasts were cultured in extracted media from chitosan adhesive to assess cytotoxicity via cell growth inhibition in a 48 hours period.

RESULTS

Chitosan adhesive successfully repaired intestine tissue, achieving a tensile strength of 14.7 +/- 4.7 kPa (mean +/- SD, n = 30) at a temperature of 60-65 degrees C. Media extracted from chitosan adhesive showed negligible toxicity to fibroblast cells under the culture conditions examined here.

CONCLUSION

A novel chitosan-based adhesive has been developed, which is insoluble, flexible, and adheres firmly to tissue upon infrared laser activation.

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 electrothermal shrinkage on the biomechanical properties of the anterior cruciate ligament: an experimental study

PURPOSE

The purpose of this study was to determine the acute effects of electrothermal shrinkage on the biomechanical properties of the anterior cruciate ligament (ACL).

TYPE OF STUDY

Randomized trial.

METHODS

Fifty fresh femur-ACL-tibia complexes harvested from fully matured pigs were used. The femur-anteromedial bundle-tibia complex specimens were randomly divided into 5 groups of 10 specimens each. In each group, radiofrequency energy set at nonablative levels was applied to the anteromedial bundle of the ACL with a bipolar radiofrequency generator. In groups I and II, radiofrequency treatment was applied to the ACL using 28 W and 45 W power, respectively, for 30 seconds. In groups III and IV, radiofrequency treatment was applied to the ACL using 28 W and 45 W power, respectively, for 60 seconds. In group V, no treatment was applied in order to obtain normal control data. The treatment was performed in physiological saline solution under a 1-N load. In each group, 8 of the 10 specimens were used for biomechanical evaluation, and the remaining 2 were used for histologic observation.

RESULTS

Concerning the length of the anteromedial bundle after the treatment, the analysis of variance (ANOVA) showed a significant difference among the 5 groups. The length in groups I, II, III, and IV was significantly shorter than that of group V. In tensile testing, the stiffness was 120, 116, 113, 89, and 156 N/mm in groups I, II, III, IV, and V, respectively. The ANOVA showed a significant difference among the groups. Groups I, II, III, and IV were significantly lower than group V, respectively. Histologic examination showed diffuse collagenous denaturation and pyknotic nuclear changes in fibroblasts at the treated portion. The collagen crimp pattern was not present in the treated area.

CONCLUSIONS

Application of RF energy to the specimens caused both shortening and weakening according to the magnitude and duration of the application.

CLINICAL RELEVANCE

These results may explain one of the causes of the poor results reported in some clinical studies. This study warns against a too optimistic application of electrothermal shrinkage to the ACL as a clinical treatment.

Thermal Damage Prediction for Collagenous Tissues Part I: A Clinically Relevant Numerical Simulation Incorporating Heating Rate Dependent Denaturation*

Subablative thermotherapy is frequently used for the treatment of joint instability related diseases. In this therapy, mechanically deformed collagenous tissues are thermally shrunk and the stability of the tissue is re-established. In this research, the thermal damage fields generated by three different clinical heating modalities (monopolar and bipolar radio frequency and Ho:YAG laser) are compared numerically using finite element analysis. The heating rate dependent denaturation characteristics of collagenous tissues are incorporated into the model using experimental data from in vitro experimentation with rabbit patellar tendons. It is shown that there are significant differences among the thermal damage profiles created by these modalities, explaining the main reason for the discrepancies reported in the literature in terms of the efficacy and safety of each modality. In the complementary paper, the accuracy of the model presented here is verified by in vitro experimentation with a model collagenous tissue and by quantifying the denaturation-induced birefringence change using Optical Coherence Tomography and Magnetic Resonance Imaging.

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.

Thermal microdebridement does not affect the time zero biomechanical properties of human patellar tendons

BACKGROUND

Thermal microdebridement for the treatment of chronic tendinopathy has recently been introduced. The effect of thermal microdebridement on the biomechanical properties of human tendons, however, remains unknown.

HYPOTHESIS

Thermal microdebridement does not affect the biomechanical properties of human patellar tendons in a cadaveric model at the time of initial treatment.

STUDY DESIGN

Controlled laboratory study.

METHODS

The central 15 mm of 12 matched, human (mean age, 71 years; 8 male, 4 female), fresh-frozen patellar tendons was divided into 3 equal 5-mm specimens. The treatment group (n = 12) underwent thermal microdebridement with a radiofrequency probe. A sham treatment group (n = 12) underwent insertion of a deactivated probe. The control group (n = 12) underwent no treatment. After treatment, each specimen was tested to failure in a servo-hydraulic materials testing machine at an elongation rate of 3 mm/s. One-way repeated measures analysis of variance was used to determine differences between groups.

RESULTS

No significant difference in ultimate stress at failure, elastic modulus, strain energy density, or strain at maximum load was found between the groups. The ultimate stress at failure for the treatment, sham, and control groups was 61.0, 66.7, and 63.0 MPa, respectively (P = .653), and the strain at maximum load was 0.12, 0.11, and 0.09, respectively (P = .279).

CONCLUSIONS

Thermal microdebridement does not affect the biomechanical properties of cadaveric human patellar tendons at the time of initial treatment.

CLINICAL RELEVANCE

It may be safe to proceed with aggressive rehabilitation after thermal microdebridement of the patellar tendon. However, the results in this cadaveric model should be interpreted with caution. Additional studies using an in vivo model will be required to completely assess the effects of thermal microdebridement on the biomechanical properties of human patellar tendons.

Neuronal regeneration after application of radiofrequency energy to collagenous tissue is affected by limb immobilization: an in vivo animal study

Despite widespread use of radiofrequency (RF)-shrinkage, there have been no studies on the influence of RF-energy on neural elements of collagenous tissue. The purpose of this study was to examine the effect of RF-shrinkage on neural structures of capsuloligamentous tissue and the recovery of neural elements under different postoperative treatment protocols. One patellar tendon of 46 New-Zealand-White rabbits was shrunk. Six rabbits were sacrificed immediately postoperative. Twenty rabbits were not immobilized, 10 were immobilized for 3 and 10 were immobilized for 6 weeks. A monoclonal antibody, specific against a neurofilament protein, was used to detect nerves and neural structures. Staining pattern of nerve fibres was significantly altered immediately postoperative. After 3 weeks the number of nerve fibres and bundles decreased significantly in immobilized and non-immobilized limbs. The loss of nerve fibres was significantly less in immobilized limbs. At 6 weeks the number of neural elements in immobilized limbs increased to the level of untreated control tissue. In non-immobilized limbs we found no recovery of neural elements 9 weeks postoperatively. At this time the number of nerve fibres and bundles was still significantly less compared to the untreated control limbs. RF-shrinkage causes significant alteration of neural elements. Under immobilization nerve fibres and bundles reach the level of normal untreated tissue. Careful rehabilitation is important after RF-shrinkage. Not only for biomechanical reasons, but also to allow the neural elements to recover, thermally modified tissue should be protected from normal physiologic loads.

Thermal profile of radiofrequency energy in the inferior glenohumeral ligament

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

CLINICAL RELEVANCE

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.

Heat-induced changes in porcine annulus fibrosus biomechanics

The intervertebral disc is implicated as the source of low-back pain in a substantial number of patients. Because thermal therapy has been thought to have a therapeutic effect on collagenous tissues, this technique has recently been incorporated into several minimally invasive back pain treatments. However, patient selection criteria and precise definition of optimum dose are hindered by uncertainty of treatment mechanisms. The purpose of this study was to quantify acute changes in annulus fibrosus biomechanics after a range of thermal exposures, and to correlate these results with tissue denaturation. Intact annulus fibrosus (attached to adjacent vertebrae) from porcine lumbar spines was tested ex vivo. Biomechanical behavior, microstructure, peak of denaturation endotherm, and enthalpy of denaturation (mDSC) were determined before and after hydrothermal heat treatment at 37 degrees C, 50 degrees C, 60 degrees C, 65 degrees C, 70 degrees C, 75 degrees C, 80 degrees C, and 85 degrees C. Shrinkage of excised annular tissue (removed from adjacent vertebrae) was also measured after treatment at 85 degrees C. Significant differences in intact annulus biomechanics were observed after treatment, but the effects were much smaller in magnitude than those observed in excised annulus and those reported previously for other tissues. Consistent with this, intact tissue was only minimally denatured by treatment at 85 degrees C for 15 min, whereas excised tissue was completely denatured by this protocol. Our data suggest that in situ constraint imposed by the joint structure significantly retards annular thermal denaturation. These findings should aid the interpretation of clinical outcomes and provide a basis for the future design of optimum dosing regimens.

Does immobilization after radiofrequency-induced shrinkage influence the biomechanical properties of collagenous tissue? An in vivo rabbit study

BACKGROUND

Despite widespread use of radiofrequency-induced shrinkage of collagenous tissue, there have been no animal studies on the effects of postoperative immobilization on the biomechanical behavior of shrunken tissue.

PURPOSE

To examine the role of postoperative immobilization after radiofrequency-induced shrinkage, with special emphasis on the biomechanical properties of shrunken collagenous tissue.

STUDY DESIGN

Controlled laboratory study.

METHODS

One patellar tendon of 66 New Zealand White rabbits was shrunk. Six rabbits were sacrificed immediately after surgery. Twenty rabbits were not immobilized, twenty were immobilized for 3 weeks, and twenty were immobilized for 6 weeks. The biomechanical parameters failure strength, stiffness, and relaxation were tested.

RESULTS

Nine weeks after surgery, biomechanical parameters were still low compared to control tendons. Shrunken tendons did not reach levels of normal tissue at any time after surgery, regardless of whether the animals had been immobilized. According to time-related development, all biomechanical parameters had the lowest levels 3 weeks after surgery. Immobilized tendons demonstrated a better and faster recovery than nonimmobilized tendons compared to the immediate postoperative level.

CONCLUSION

Postoperative immobilization supports recovery of biomechanical properties after shrinkage. Despite immobilization, biomechanical properties of shrunken tissue did not completely reach levels of normal tissue.

CLINICAL RELEVANCE

Careful rehabilitation is imperative after radiofrequency-induced shrinkage. This animal model supports an immobilization period of at least 6 weeks after surgery.

Temperature requirements for altering the morphology of osteoarthritic and nonarthritic articular cartilage: in vitro thermal alteration of articular cartilage

BACKGROUND

Radiofrequency and laser thermal chondroplasty procedures are performed to debride and smooth fibrillated, articular cartilage.

HYPOTHESIS

Temperature requirements necessary to achieve morphological change will be lower in fibrillated arthritic cartilage as compared with nonarthritic articular cartilage.

STUDY DESIGN

Controlled laboratory study.

METHODS

A thermal cell-culture chamber was mounted on a stereoscopic microscope and coordinated with a custom temperature-control program. Nonarthritic and osteoarthritic articular cartilage specimens were sectioned into full-thickness slices. The articular sections were exposed to temperatures incrementally from 37 masculine C to 75 masculine C. Real-time, digital capture microscopy was used to visualize and analyze the morphological changes undergone by the articular cartilage specimens.

RESULTS

Arthritic articular cartilage displayed morphological change at 56.5 +/- 1.7 masculine C. Loss of fibrillation was the initial morphological change visualized. Continued thermal exposure caused a shrinkage effect of the entire tissue section that was similar to the change seen in nonarthritic sections. Nonarthritic cartilage displayed morphological change at 60.9 +/- 1.9 masculine C.

CONCLUSIONS

Consistent characteristic morphological changes were found at distinct temperatures in osteoarthritic and nonarthritic articular cartilage.

CLINICAL RELEVANCE

This information begins to establish the thermal parameters required for morphological change of osteoarthritic articular cartilage.

The effect of radiofrequency thermal capsulorrhaphy on glenohumeral translation, rotation, and volume

The purpose of this study is to evaluate the effects of radiofrequency (RF) thermal capsulorrhaphy on the kinematic properties of the glenohumeral joint as determined by changes in resistance to multidirectional translational forces, alteration in the range of internal and external rotation, and changes in glenohumeral joint volume. Nonablative RF thermal energy was used to contract the glenohumeral joint capsule in 6 cadaveric shoulders. Measurements of translation were made after application of a 30-N load in anterior, posterior, and inferior directions. The maximum arc of internal and external rotation after application of a 1-N-m moment was also determined for vented specimens before and after thermal capsulorrhaphy. The percent reduction in glenohumeral capsular volume was measured by use of a saline solution injection-aspiration technique. Capsular shrinkage resulted in reductions in anterior, posterior, and inferior translation. The largest percent reductions in anterior translation were seen in external rotation at 45 degrees (48%, P <.05) and 90 degrees (41%, P <.05) abduction. For inferior translation, the largest percent reductions were seen in internal rotation at 45 degrees (40%, P <.05) and 90 degrees (45%, P <.05) abduction. Reductions in posterior translation were noted in internal rotation at 45 degrees (27%, P <.05) and 90 degrees (26%, P <.05) abduction. Other changes in translation were observed but were not statistically significant. The maximum arc of humeral rotation was reduced by a mean of 14 degrees at 45 degrees abduction and 9 degrees at 90 degrees abduction. The mean percent reduction in capsular volume for all shoulders was 37% (range, 8%-50%). This could not be correlated with percent reductions in translation and rotation. This study demonstrated the significant effect of RF thermal capsulorrhaphy in reducing glenohumeral multidirectional translation and volume with only a small loss of rotation in cadaveric shoulders.

Volumetric change in the shoulder capsule after open inferior capsular shift versus arthroscopic thermal capsular shrinkage: a cadaveric model

The purpose of this study was to compare the percentage of glenohumeral intracapsular volume reduction after open inferior capsular shift and arthroscopic thermal capsulorrhaphy. Twelve matched, fresh-frozen cadaveric shoulders were used for the study. Intraarticular glenohumeral volume measurements were obtained by injecting a viscous fatty acid sulfate solution into the joint. In the 6 right shoulders, a standard anterior-inferior capsular shift was performed, and in the 6 matching left shoulders, an arthroscopic thermal capsular shrinkage was performed. After the procedures, the capsular volumes were re-measured. The open inferior shift procedure resulted in a mean decrease in glenohumeral volume of 50.2% (range, 43%-56%). Arthroscopic thermal capsulorrhaphy decreased shoulder intraarticular volume by a mean of 29.7% (range, 26%-36%). Both the open capsular shift and arthroscopic thermal shrinkage procedures produced well-documented volumetric reductions in the shoulder capsules. The open shift reduced intraarticular shoulder volume significantly more than arthroscopic thermal capsular shrinkage.

Glenohumeral volume reduction in arthroscopic shoulder reconstruction: a cadaveric analysis of suture plication and thermal capsulorrhaphy

PURPOSE

The purpose of this study was to objectively assess glenohumeral volume changes after arthroscopic suture plication, arthroscopic thermal capsulorrhaphy, and combined suture and thermal treatment.

TYPE OF STUDY

Cadaveric study.

METHODS

Five matched pairs of cadaver shoulders were treated with either thermal capsulorrhaphy (n = 5) or arthroscopic suture plication (n = 5). The shoulders treated with plication were then treated with thermal capsulorrhaphy to form a combined treatment group (plication and thermal). Preoperative and postoperative glenohumeral volume measurements were obtained, and the techniques were statistically compared with a 1-factor analysis of variance.

RESULTS

All 3 procedures produced marked decreases in glenohumeral capsular volume. Suture plication reduced intra-articular volume an average of 19.0%. Thermal capsulorrhaphy resulted in a mean capsular volume reduction of 33.4%. Combined treatment with suture plication and thermal capsulorrhaphy reduced glenohumeral volume an average of 41.0%. Both thermal capsulorrhaphy and the combined treatment produced significantly greater reduction in glenohumeral volume than plication alone (P <.0001). Although combined suture plication and thermal capsulorrhaphy resulted in greater reduction in capsular volume than thermal capsulorrhaphy alone, the differences were not statistically significant.

CONCLUSIONS

Our results indicate that arthroscopic suture plication and thermal capsulorrhaphy are both effective in reducing glenohumeral intra-articular volume. Thermal capsulorrhaphy alone or in combination with suture plication led to significantly greater reduction in capsular volume when compared with isolated suture plication.