Use of Electrocautery to Facilitate Suture Passage Through the Greater Trochanter of the Femur: A Biomechanical Study.

Introduction: The specific aims of this study were to evaluate (1) the axial force reduction of suture passage utilizing electrocautery when applied to the greater trochanter of the femur, (2) the temperature change caused while using electrocautery for suture passage, and (3) the failure loads and failure modes utilizing this technique. Methods: Five matched pairs of fresh-frozen femurs were used and classified into two groups: with electrocautery on needle (study group) and without electrocautery on needle (control group). Two bicortical, osseous tunnels were made around the insertion of the gluteus medius tendon. Each specimen was sequentially tested in a needle penetration test and a single load-to-failure test. A #5 Ethibond suture with a straight needle was used. Results: Electrocautery reduced the peak axial force for bone penetration in 40% (near cortex) and 70% (far cortex) of the trials, and no significant difference was detected between groups or between two osseous tunnels. The average peak force was significantly higher for the far cortex for both groups and for both osseous tunnels compared to the near cortex. There was no significant change in temperature of the tunnel site with electrocautery. Ninety percent of the samples experienced bone tunnel failure for the study group compared to 70% in the control group. The average ultimate failure load for the study group was lower compared with the control group, but this finding was not statistically significant (range: 6%-15%). Conclusions: Suture passage using electrocautery may not significantly decrease the peak force needed to pass a needle directly through the greater trochanter.

Biomechanical characteristics of 9 arthroscopic knots.

PURPOSE: To determine the optimal arthroscopic slipknot through comparison of ease of placement, loop security, knot security, and amount of suture material needed using a new suture material. METHODS: Nine commonly used arthroscopic knots (Dines, Field, Nicky, Hu, San Diego, Snyder, Tennessee slider, Triad, and Tuckahoe) were tested by use of modern suture material, FiberWire (Arthrex, Naples, FL), with the Instron materials testing machine (Instron, Norwood, MA) for ease of knot placement (forward and backward sliding), loop security, and knot security. The amount of suture material needed to create the knot was compared by use of the knot weight. Analysis of variance with Kruskal-Wallis analysis and Bonferroni correction (alpha < .01) was used to compare different knots. RESULTS: The Tennessee slider knot sustained the greatest force at failure (269 N), the greatest knot resistance (32 N), and the smallest mass (8.5 mg). The Dines was the only knot superior in all 3 knot placement categories. The Nicky held the most loop force (66 N), and the Tuckahoe had the greatest loop resistance (20 N) (P < .01 for all except mass [P < .05]). CONCLUSIONS: Our study comprehensively presents ease-of-placement and security characteristics of 9 common and new arthroscopic knots using modern FiberWire suture. The Tennessee slider knot showed superior characteristics in knot security and knot mass. The Dines knot was the most ideal knot to place. However, the surgeon will need to review the individual knot characteristics and select the knot most suited to application. CLINICAL RELEVANCE: This study analyzed 9 arthroscopic knots with modern suture material and identified those with superior characteristics.

Cemented total hip replacement cable debris and acetabular construct durability.

BACKGROUND: Third-body wear can adversely affect the outcome of total hip arthroplasty by causing increased polyethylene wear, osteolysis, and component loosening. We hypothesized that there would be greater generation and migration of metal debris to the bearing surfaces in hips in which cobalt-chromium cables were used to reattach the osteotomized greater trochanter when compared with hips in which stainless steel wires were used. METHODS: Between June 1981 and December 1983, 196 consecutive total hip arthroplasties were performed with use of an Iowa stem and a titanium-backed cemented acetabular component, with cobalt-chromium cable trochanteric reattachment. After nineteen to twenty years of follow-up, the patients were evaluated with regard to the depth of head penetration into the polyethylene (as a surrogate for wear), osteolysis, loosening, and the need for revision. The results were compared with those for a series of 304 total hip arthroplasties that were performed by the same surgeon from January 1984 to December 1985 with use of the same components and the same surgical technique, but with stainless steel wire trochanteric reattachment. The two groups had a comparable nineteen to twenty-year follow-up. All living patients (fifty-nine hips in the cable group and ninety-two hips in the wire group) had minimum ten-year follow-up radiographs. RESULTS: The polyethylene wear rate was 0.101 mm/yr for the cable group and 0.082 mm/yr for the wire group (p = 0.039). For the living patients, the rate of revision of the acetabular component because of aseptic loosening was 37.3% (twenty-two hips) for the cable group and 20.7% (nineteen hips) for the wire group (p = 0.025). The rate of acetabular osteolysis was 44% (twenty-six hips) for the cable group and 26% (twenty-four hips) for the wire group (p = 0.022). Kaplan-Meier analysis with revision of the acetabular component because of aseptic loosening as the end point demonstrated survival rates of 73.7% +/- 9% and 83% +/- 7% for the cable and wire groups, respectively, at twenty years (p = 0.03). CONCLUSIONS: Because cable trochanteric attachment led to significantly greater polyethylene wear, osteolysis, acetabular loosening, and acetabular revision, presumably due to third-body metallic debris generation in this cemented total hip replacement construct, surgeons should be aware of the deleterious effects of third-body debris and avoid the use of potential debris generators in the total hip arthroplasty construct. If cable is used and fretting is recognized, especially with intra-articular migration of metallic material or nonunion of the greater trochanter, consideration should be given to cable removal.