Gary S. Fanton

The Thermal Effect of Monopolar Radiofrequency Energy on the Properties of Joint Capsule An In Vivo Histologic Study Using a Sheep Model

The purpose of this in vivo study was to analyze the short-term tissue response of joint capsule to monopolar radiofrequency energy and to compare the effects of five power settings at 65°C on heat distribution in joint capsule. In 12 mature Hampshire sheep, the medial and lateral aspects of both stifles were treated with monopolar radiofrequency energy under arthroscopic control in a single uniform pass to the synovial surface. The radiofrequency generator power settings were 0, 10, 15, 20, 25, and 30 watts (N 8/group). The electrode tip temperature was 65°C. Histologic analysis at 7 days after surgery revealed thermal damage of capsule at all radiofrequency power settings. The lesions cross-sectional area, depth, vascularity, and inflammation were commensurate with radiofrequency power. Tissue damage was indicated by variable inflammatory cell infiltration, fusion of collagen, pyknosis of fibroblasts, myonecrosis, and vascular thrombosis, whereas synovial hyperplasia, fibroblast proliferation, and rowing of sarcolemmal nuclei demonstrated regenerative processes. This study revealed that radiofrequency power settings and heat loss through lavage solution play a significant role in heat distribution and morphologic alterations in joint capsule after arthroscopic application of monopolar radiofrequency energy.

Septic arthritis in postoperative anterior cruciate ligament reconstruction.

A review of postoperative infected anterior cruciate ligament reconstructions was done on 3500 consecutive arthroscopic procedures. The purpose was to assess incidence, diagnosis, treatment, and outcome factors. Six postoperative intraarticular infections were detected. Average followup was 3 years (range, 2–8 years). The rate of infection was 0.14%. Five men and one woman with a median age of 32.5 years (range, 20–51 years) comprised the study group. The average interval from the onset of symptoms to the initial arthroscopic intervention was 7.5 days (range, 2–20 days). Staphylococcus aureus was present in three knees, Staphylococcus epidermidis in two, and Streptococcus nonhemolytic in one. All patients had initial arthroscopic debridement and lavage followed by 6 weeks of intravenous antibiotics. Two grafts were removed: one patient had delayed ligament reconstruction and the other had total knee arthroplasty. The remaining patients had full range of motion. In the group with the best result, two patients had Staphylococcus epidermidis and one had Staphylococcus aureus, which was treated 2 days after clinical symptoms began. The other two patients infected with Staphylococcus aureus had unsatisfactory results. Anterior cruciate ligament infection is rare, but diagnosable. When treated early with appropriate antibiotic therapy and arthroscopic debridement, four of six grafts were retained. If the infection does not respond rapidly to early therapy, then graft removal is an option.

Monopolar Radiofrequency Energy Effects on Joint Capsular Tissue: Potential Treatment for Joint Instability An In Vivo Mechanical, Morphological, and Biochemical Study Using an Ovine Model

The purpose of this study was to evaluate the thermal effect of monopolar radiofrequency energy, a potential treatment means for joint instability, on the mechanical, morphologic, and biochemical properties of joint capsular tissue in an in vivo ovine model. The energy was applied arthroscopically to the synovial surface of the femoropatellar joint capsule of 24 sheep. The sheep were sacrificed at 0, 2, 6, and 12 weeks after surgery (6 per group). Monopolar radiofrequency energy initially caused a significant decrease in tissue stiffness and an increase in tissue relaxation properties, followed by gradual improvement in the tissues mechanical properties by 6 weeks after surgery. Microscopic examination illustrated that radiofrequency energy initially caused collagen hyalinization and cell necrosis, followed by active tissue repair. Biochemical analysis revealed that treated collagen was significantly more trypsin-susceptibile than untreated collagen at 0 and 2 weeks after surgery, indicating early collagen denaturation. This study demonstrated that this treatment initially caused a significantly deleterious effect on the mechanical properties of the joint capsule, which was associated with partial denaturation of joint capsular tissue. This was followed by gradual improvement of the mechanical, morphologic, and biochemical properties of the tissue over time.

Two-year outcome of arthroscopic Bankart repair and electrothermal-assisted capsulorrhaphy for recurrent traumatic anterior shoulder instability

PURPOSE Arthroscopic treatment of chronic anterior shoulder instability in active athletes is reportedly less successful than open techniques. We performed arthroscopic stabilization for confirmed capsulolabral avulsions and followed-up patients prospectively for a minimum of 24 months. TYPE OF STUDY Prospective nonrandomized study. METHODS We studied 42 patients (mean age, 26 years) with recurrent traumatic anterior dislocations. They reported an average of 9 dislocations preoperatively. An average of 69 months elapsed from initial dislocation to surgery. The shoulders underwent arthroscopic capsulolabral repair with either a suture anchor and horizontal mattress suture, or an absorbable tack. Each shoulder also was treated with a monopolar radiofrequency probe for thermal shrinkage of the middle, anteroinferior, and posteroinferior glenohumeral ligaments. Patients were evaluated prospectively for pain, motion, stability, and function using the modified Rowe score. RESULTS At a mean of 28 months postoperatively, 38 patients had returned to their preinjury sports. Three patients (7%) had a traumatic redislocation. Using the modified Rowe score, statistically significant improvements were noted for pain, stability, and function. There was no significant change in motion. The overall modified Rowe score improved from 38 points preoperatively to 89 points at final evaluation (P <.001). CONCLUSIONS These results indicate that arthroscopic treatment of patients with recurrent traumatic anterior instability yields results comparable to open procedures, including athletes involved in high-level contact and collision sports. We believe that addressing capsular laxity surgically is critical, particularly when dealing with chronic instability. This procedure allows the surgeon to reliably correct the labral detachment and the capsular redundancy while preserving motion and minimizing morbidity.

The Effect of Monopolar Radiofrequency Treatment Pattern on Joint Capsular Healing In Vitro and In Vivo Studies Using an Ovine Model

The purpose of this study was to compare joint capsular healing after two delivery patterns of monopolar radiofrequency energy: 1) uniform treatment of the joint capsule (paintbrush pattern) and 2) multiple single linear passes (grid pattern). First, an in vitro study was performed to compare the percent shrinkage of these two treatment patterns using the femoropatellar joints (stifles) of six sheep. Monopolar radiofrequency energy (settings, 70°C/15W) was applied to the lateral joint capsule; the treated area was approximately 10 10 mm. There was no significant difference in shrinkage between the grid (27% 8.7%) and paintbrush (29% 7.9%) patterns. In the in vivo study, stifles of 24 sheep were randomly assigned to the paintbrush or the grid pattern groups and treatment was performed arthroscopically. Sheep were sacrificed immediately after surgery, or at 2, 6, or 12 weeks after surgery. At 6 weeks after surgery, confocal microscopy demonstrated that treated areas had almost completely repaired in the grid group; some nonviable areas were still present in the paintbrush group. Mechanical testing at 6 weeks indicated that joint capsule in the grid group had better mechanical properties than capsule in the paintbrush group. This study revealed that radiofrequency treatment of joint capsule in a grid pattern allowed faster healing than tissue treated in a paintbrush pattern.

Arthroscopic electrothermal surgeryof the shoulder

Abstract In orthopedics, RF energy has been used to cut tissue targeted for removal, coagulate bleeding vessels (hemostasis),and to denervate pain sensing nerves and irritated tissue. Newer applications using temperature-controlled devices cause tissue contraction that is effective in treating shoulder instability The tip of the RF electrode is arthroscopically positioned against the tissue to create the desired thermal effect. The goal of the RF energy application is to produce a well-defined area of tissue heating that undergoes shrinkage, denaturization, or ablation.

Histologic evaluation of the glenohumeral joint capsule after the laser-assisted capsular shift procedure for glenohumeral instability.

Glenohumeral joint capsule obtained from 42 patients who had undergone an arthroscopic laser-assisted capsular shift procedure was evaluated histologically. A total of 53 samples from the anterior inferior glenohumeral ligament of the joint capsule were collected before and at various times after the procedure (range, 0 to 38 months). Despite glenohumeral instability, joint capsule of the patients before the procedure showed no significant histologic lesions. Laser treatment significantly altered the histologic properties of the tissue as evidenced by hyalinization of collagen and necrotic cells (time 0). Tissues sampled during the short-term period (3 to 6 months) after the procedure demonstrated fibrous connective tissue with reactive cells and vasculature. Collagen and cell morphology returned to normal in the middle- to long-term period (7 to 38 months) after the procedure, while the number of fibroblasts remained elevated. Joint capsule collected from the shoulders of six patients who experienced stiffness after the procedure showed persistent synovial, cellular, and vascular reaction even after 1 year postoperatively, the cause of which is unclear. This study re-

The mechanism of joint capsule thermal modification in an in-vitro sheep model.

The purpose of this study was to understand the mechanism responsible for joint capsule shrink-age after nonablative laser application in an in vitro sheep model. Femoropatellar joint capsular tissue specimens harvested from 20 adult sheep were treated with one of three power settings of a holmium:yttrium-aluminum-garnet laser or served as a control. Laser treatment significantly shortened the tissue and decreased tissue stiffness in all three laser groups, whereas failure strength was not altered significantly by laser treatment. Transmission electron microscopic examination showed swollen collagen fibrils and loss of membrane integrity of fibroblasts. A thermometric study revealed nonablative laser energy caused tissue temperature to rise in the range of 64° C to 100° C. Electrophoresis after trypsin digestion of the tissue revealed significant loss of distinct alpha bands of Type I collagen in laser treated samples, whereas alpha bands were present in laser treated tissue without trypsin digestion. The results of this study support the concept that the primary mechanism responsible for the effect of nonablative laser energy is thermal denaturation of collagen in joint capsular tissue associated with unwinding of the triple helical structure of the collagen molecule.

Anterior cruciate ligament reconstruction using cryopreserved allografts.

Primary ACL reconstruction historically has been done using autograft tissues whereas allografts have been limited to revision cases and patients who are older or with lower physical demands because some animal studies suggested a slower biologic incorporation rate. The purpose of the current study was to evaluate the effectiveness of the cryopreserved Achilles tendon allograft in primary ACL reconstruction in a consecutive series of athletes. Fifty consecutive patients with a strenuous or moderate preinjury activity level, as defined by the International Knee Documentation Committee (IKDC), had ACL reconstruction using cryopreserved Achilles tendon allografts secured with bioabsorbable interference screws. Five patients were professional athletes. The average age of the patients was 36 years (range, 17–50 years). A 3- to 5-year followup study was done in all of the patients using the IKDC form. Tunnel widening was measured in the lateral radiographs at the widest level. The overall outcome was normal or nearly normal in 94% of the patients. No failures were reported in this series. Forty-six patients (92%) returned to their same preinjury sport activity level. The average KT-1000 side-to-side difference was 2.3 mm. Average tibial tunnel widening was 2.7 mm (range, 0–6 mm); no significant correlation was observed between increased tunnel size and a fair or poor clinical outcome. This experience shows that favorable results can be obtained with cryopreserved Achilles tendon allografts in athletes in whom avoiding donor site morbidity may be an issue in terms of a prompt return to sport.

Arthroscopic monopolar radiofrequency thermal stabilization for chronic lateral ankle instability: A preliminary report on 10 cases

This study represents a preliminary review of 10 patients having undergone arthroscopic monopolar thermal stabilization for ankle instability from October 1996 to June 1998. All patients in this study expressed mild to moderate chronic ankle instability complaints and were dissatisfied with their attempts at conservative care. Subjective clinical results were evaluated in all patients having undergone this procedure utilizing a modified version of the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. In addition, eight of these patients underwent pre- and postoperative stress radiographs. The average age of the patient population in this study was 34.5 +/- 9.26 years. The preoperative AOFAS scores averaged 58.3 +/- 8.96 and the postoperative were 88.1 +/- 11.09 points. Patients returned to full activities on the average of 3 months. Postoperative ankle varus stress test reduced on the average of 2.8 degrees +/- 2.77 degrees, while the anterior drawer measurements reduced 4.8 +/- 1.83 mm. The reduction in anterior drawer test amounted to an approximate 60% decrease in talar excursion postoperatively. All patients who underwent this procedure achieved ankle stability and commented that they would undergo the procedure again.