Effect of tibial drill-guide angle on the mechanical environment at bone tunnel aperture after anatomic single-bundle anterior cruciate ligament reconstruction

Purpose

The tibial drill-guide angle in anterior cruciate ligament (ACL) reconstruction influences the tunnel placement and graft-tunnel force, and is potentially associated with post-operative tunnel widening. This study aimed to examine the effect of the drill-guide angle on the stress redistribution at the tibial tunnel aperture after anatomic single-bundle ACL reconstruction.

Methods

A validated finite element model of human knee joint was used. The tibial tunnel with drill-guide angle ranging from 30° to 75° was investigated. The post-operative stress redistribution in tibia under the compressive, valgus, rotational and complex loadings was analysed.

Results

Compressive loading played a leading role on the stress redistribution at intra-articular tibial tunnel aperture. After ACL reconstruction, stress concentration occurred in the anterior and posterior regions of tunnel aperture while stress reduction occurred in the lateral and posteromedial regions under the compressive loading. Stress redistribution was partially alleviated by using the drill-guide angle ranging from 55° to 65°.

Conclusions

The present study quantified the effect of bone tunnel drill-guide angle on the post-operative stress redistribution. This phenomenon potentially contributed to tunnel widening. A tunnel drill-guide angle ranging from 55° to 65° was proposed based on the biomechanical rationale. It could serve as a helpful surgical guide for ACL reconstruction.     

A propensity-matched analysis of clinical outcomes between open thyroid lobectomy and high-intensity focused ultrasound (HIFU) ablation of benign thyroid nodules

Background

High-intensity focused ultrasound is a promising, nonoperative treatment for benign thyroid nodules. Our study aimed to compare treatment outcomes of single-session high-intensity focused ultrasound ablation with open lobectomy after propensity score matching.

Arthroscopic repair of Bankart lesion in traumatic anterior-inferior shoulder instability using the two-portal method: A preliminary report

BackgroundIn this report, we describe our preliminary clinical results of arthroscopic Bankart repair in traumatic anterior-inferior shoulder instability using the two-portal method.MethodFrom August 2009 to December 2011, arthroscopic repair of Bankart lesion using this method was performed in 16 consecutive patients who were prospectively enrolled. Fifteen shoulders were treated with two-anchor sutures and one was treated with three-anchor sutures. Twelve patients received metallic anchor screws and four patients received bioanchor screws. The assessments were performed using the Rowe score, the University of California at Los Angeles shoulder rating scale, the American Shoulder and Elbow Surgeons score, and the shoulder range of motion (ROM) deficit.ResultsWith an average follow-up period of 22.9 months, all shoulder scores improved after surgery (p < 0.001). The average ROM deficit of the operated shoulders was not significant as compared with the healthy side in forward elevation (p > 0.05), but was significant in external rotation (p < 0.05). All of the 16 shoulders remained stable (100%) after the arthroscopic repair surgery. All patients returned to their preinjury levels of daily activity without recurrent problems.ConclusionIn patients with traumatic anterior glenohumeral instability, arthroscopic Bankart repair with the two portal method can provide good results. It can be an alternative method of treating patients with Bankart lesion without associated major glenoid defect or rotator cuff lesion in traumatic anterior-inferior instability.     

Revision endoscopic frontal sinus surgery with surgical navigation.

BACKGROUND: Revision surgery of the frontal sinus remains one of the most difficult operations for the endoscopic surgeon. Most agree that knowledge and recognition of its complex anatomy and sparing of frontal recess mucosa are keys to a successful operation. The use of surgical navigation systems may allow for more precise dissections and greater rates of frontal recess patency. METHODS: Retrospective review of all patients undergoing revision endoscopic frontal sinus surgery with surgical navigation was performed with a minimum 24-month follow-up. RESULTS: Sixty-seven patients underwent revision endoscopic frontal sinus surgery with surgical navigation. The average follow-up was 32 months. Fifty-eight (86.6%) had a patent frontal recess and significant subjective improvement in symptoms. No patient underwent external frontal sinus obliteration, and there were no major complications. CONCLUSIONS: Endoscopic techniques with surgical navigation are effective in revision frontal sinus cases. The dissection of remnant agger nasi, obstructing frontal and supraorbital cells are necessary to widen the anterior-posterior as well as the medial-lateral dimensions of the recess. Computer navigational systems appear to serve as a valuable adjunct in preoperative planning and safe intraoperative dissection.     

Preoperative ketamine improves postoperative analgesia after gynecologic laparoscopic surgery

In this study, we evaluated the preemptive effect of a small dose of ketamine on postoperative wound pain. In a randomized, double-blinded, controlled trial, we compared the analgesic requirement in patients receiving preincision ketamine with ketamine after skin closure or placebo after gynecologic laparoscopic surgery. One-hundred-thirty-five patients were randomly assigned to receive preincision or postoperative ketamine 0.15 mg/kg or saline IV. Anesthetic technique was standardized. Patients were interviewed regularly up to 4 wk after surgery. Pain score, morphine consumption, side effects, and quality of recovery score were recorded. Patients receiving preincision ketamine had a lower pain score in the first 6 h after operation compared with the postoperative (P = 0.001) or placebo groups (P < 0.001). The mean (95% confidence intervals) time to first request for analgesia in the preincision group, 1.8 h (1.4-2.1), was longer than the postoperative group, 1.2 h (0.9-1.5; P < 0.001), or the placebo group, 0.7 h (0.4-0.9; P < 0.001). The mean +/- SD morphine consumption in the preincision group, 1.5 +/- 2.0 mg, was less than that in the postoperative group, 2.9 +/- 3.1 mg (P = 0.04) and the placebo group, 3.4 +/- 2.7 mg (P = 0.003). There was no significant difference among groups with respect to hemodynamic variables or side effects. No patient complained of hallucinations or nightmares. We conclude that a small dose of ketamine is not only safe, but it also provides preemptive analgesia in patients undergoing gynecologic laparoscopic surgery. IMPLICATIONS: In women undergoing laparoscopic gynecologic surgery, a small preoperative dose of ketamine (0.15 mg/kg) produced preemptive analgesia. There were no significant hemodynamic and psychological side effects with this dose.     

Posterior cruciate ligament-substituting total knee arthroplasty in young rheumatoid patients with advanced knee involvement

The integrity and strength of the posterior cruciate ligament (PCL) in the rheumatoid knee are known to be suboptimal. However, the results of PCL-substituting total knee arthroplasty in rheumatoid patients are not well documented. We reviewed 86 PCL-substituting total knee arthroplasties in 52 rheumatoid patients with grade IV or V radiographic disease. The mean age at surgery was 41.9 years. All patients underwent follow-up evaluation for an average of 7.8 years. Revision was performed for 1 knee because of aseptic loosening of the tibial component, and for 3 knees because of deep infection. An isolated insert exchange was performed on one knee. Using revision of any component for aseptic loosening or radiographic loosening as the end point, the mean 10-year survival rate was 94.0%.     

Ex vivo comparative study using the Endolifter® as a traction device for enhancing submucosal visualization during endoscopic submucosal dissection

Background

Endoscopic submucosal dissection (ESD) is a technically demanding procedure, and exposure of the submucosa depends on the action of gravity and submucosal injection. The aim of the study was to investigate the effectiveness of the Endolifter^® as a traction device for enhancing submucosal visualization during ESD.

Methods

This was a prospective ex vivo comparative study conducted between September 2010 and March 2011 in the Prince of Wales Hospital. Consecutive ESDs were performed by four experienced endoscopists in an ex vivo ESD model with or without the Endolifter^®. The Endolifter^® allows simultaneous grasping, retracting and lifting of the mucosa during ESD, resulting in exposure of the submucosa. Each of the procedures were recorded and reviewed later by two independent assessors. The outcome measures included the proportion of time that the submucosa was visualized during the procedures (SM ratio), procedural times, perforation rates, amount of submucosal injections, and the difficulty of the procedure.

Results

Forty-eight gastric ESD procedures were performed on the model. The SM ratio was higher in the Endolifter^® group (P = 0.007), particularly for lesions located at the antrum (P < 0.001). The time required for submucosal dissection and the total procedural time were also less in the Endolifter^® group. The endoscopists rated the ESD procedures in the Endolifter^® group as less difficult (P = 0.033).

Conclusions

The Endolifter^® improved submucosal visualization during gastric ESD and reduces the difficulty of performing the procedures. The device may improve the ease of performing ESD in low-volume centers or large mucosal lesions.     

Diabetes and the outcome of infrainguinal bypass for critical limb ischaemia

Aim: To examine the influence of diabetes mellitus (DM) on the outcome of infrainguinal bypass operations performed for critical foot ischaemia in Chinese patients. Methods: A prospective audit of 265 consecutive infrainguinal bypass operations. Results: Diabetic patients suffered more frequently from ischaemic heart disease (48%vs 25%, P= 0.001) and tissue loss (90%vs 79%, P = 0.01) at presentation. Cigarette smoking was more prevalent in the non‐diabetic (NDM) group (72%vs 51%, P = 0.001). Arterial segments distal to the common femoral artery were more often used as inflow to bypass graft in DM patients (36%vs 22%, P = 0.02). Operative mortality (seven DM vs one NDM, P = 0.19). Early graft failure (7% in DM group vs 10% in NDM group, P = 0.24), wound infection rate (24% in DM group vs 17% in NDM group, P = 0.21), early limb loss (9% in DM group vs 6% in NDM group, P = 0.66) were comparable. However, hospital mortality was higher in DM patients (8%vs 1%, P = 0.04). DM patients more frequently required further surgical debridement postoperatively (20%vs 9%, P = 0.04). Long‐term, patient survival was inferior in the DM group (43% NDM vs 33% DM at 5 years, P = 0.03). Primary graft patency (46% DM vs 34% NDM at 4 years P = 0.19), secondary graft patency (57% DM vs 47% NDM at 4 years P = 0.14) and limb salvage rate (78%vs 81% at 5 years, P = 0.79) were comparable. Conclusion: Diabetes mellitus adversely affects hospital mortality and long‐term survival. Graft patency and limb salvage are not compromised by the presence of DM.