Double-tunnel Technique Research Articles

Peroral endoscopic myotomy with diverticulotomy using a double tunnel technique: finding your way to an elusive lower esophageal sphincter in spastic achalasia and epiphrenic diverticulum

Peroral endoscopic myotomy with diverticulotomy using a double tunnel technique: finding your way to an elusive lower esophageal sphincter in spastic achalasia and epiphrenic diverticulum

Single Versus Double Tunnel Fixation in Medial Patellofemoral Ligament Reconstruction: A Meta-Analysis.

The purpose of this meta-analysis was to conduct a comparative analysis of clinical scores and complication rates among patients experiencing recurrent patellar dislocation who underwent medial patellofemoral ligament (MPFL) reconstruction using both single and double tunnel techniques. A comprehensive search was conducted across electronic databases including PubMed, the Cochrane Library, Web of Science, and Google Scholar to retrieve articles relevant to MPFL reconstruction utilising the tunnel technique. Subsequently, meta-analyses were undertaken to assess complication rates and changes in clinical scores before and after surgery. Following this, sensitivity analysis and meta-regression analysis were performed to scrutinise potential confounding variables. A total of thirty-two studies were included in the analysis, comprising twenty-seven non-comparative studies and five comparative studies. The findings revealed a similarity in postoperative complication rates between the single and double tunnel fixation techniques: [9.0% (95%CI, 4.0%-15.6%) versus 8.9% (95%CI, 4.7%-14.1%, p = 0.844)]. Likewise, no statistically significant differences were observed in Lysholm scores [34.1 (95%CI, 26.7-41.5) versus 33.8 (95%CI, 27.7-40.0, p = 0.956)], Kujala scores [29.4 (95%CI, 22.3-36.4) versus 27.3 (95%CI, 22.3-32.3, p = 0.637)], and Tegner score change [1.1 (95%CI, 0.8-1.4) versus 0.7 (95%CI, -0.2-1.6, p = 0.429)] before and after MPFL reconstruction, respectively, using these two techniques. In conclusion, the authors found that the clinical functional improvement and complication rates in MPFL reconstruction using the single tunnel fixation technique are comparable to those achieved with the double tunnel fixation approach. However, to further advance the understanding in this field, additional randomised controlled studies must be conducted to provide further insights. Key Words: MPFL reconstruction, Bone tunnel, Patellar dislocation, Meta-analysis.

Meniscal allograft transplantation: A matched-pair analysis reveals worse sportactivity level but similar clinical improvement and survival in women compared to men.

The aim of this study was to assess how gender might affect the clinical outcome and survival of meniscal allograft transplantation (MAT). A total of 358 patients (23.2% women, 76.8% men) were treated with fresh-frozen nonirradiated allografts implantated arthroscopically using a single- or double-tunnel technique without bone plugs and peripheral suture to the capsule with 'all-inside'stitches. Patients were evaluated at baseline and 2-year follow-up with the Lysholm score, visual analogue scale (VAS) pain, the Knee Osteoarthritis Outcome Score (KOOS) subscalesand Tegner score. Women presented higher body mass index (p < 0.0005), poorer baseline VAS (p = 0.012), Lysholm score (p = 0.005), KOOS symptom (p = 0.034) and KOOS pain (p = 0.030), Tegner score (preinjury and basal, p < 0.0001 and p = 0.002, respectively), a lower number of previous (p = 0.039) and concurrent (p = 0.001) anterior cruciate ligament reconstructionsand a higher number of concurrent procedures (p = 0.032) and distal femoral osteotomies (p = 0.024). Worse results were documented in women at 2 years, with lower Lysholm score(p = 0.024) and Tegner score(p = 0.007)and a lower clinical survival rate (p = 0.03) (67.5% vs.82.2%) in the overall patient cohort. However, the matched-pair analysis only confirmed a lower Tegner score value at 2 years (p = 0.016), while underlying the interplay of sex, ageand concomitant cartilage lesions in determining the clinical outcome. The analysis of this large series of patients affected by postmeniscectomy syndrome and treated with MAT revealed gender differences. While both genders benefited from a significant improvement, the female population presents more often with older age, concomitant cartilage lesionsand a lower activity level, all factors contributing towards a lower clinical success after MAT. Level III, comparative study.

A209 ESOPHAGEAL EPIDERMOID METAPLASIA: ADVOCATING FOR A PRIMARY ENDOSCOPIC SUBMUCOSAL DISSECTION APPROACH

Abstract Background Esophageal epidermoid metaplasia (EM), or leukoplakia, is a rare finding on endoscopy; typically seen incidentally as a white plaque and histologically characterized by orthokeratosis. The link between EM and squamous neoplasia has been identified. There is no consensus on the management of EM. Aims To present a case of circumferential esophageal EM managed with endoscopic submucosal dissection (ESD). Methods Case report and review of the literature Results A 56-year-old female with a known history of EM was referred for consideration of ESD due to dysplastic progression confirmed on histopathology. Previous attempts at eradication included argon plasma coagulation and staged band mucosectomy. Fully circumferential ESD was performed over a 100mm segment in the mid esophagus using the double tunnel technique. Histopathology revealed multifocal low-grade squamous intraepithelial neoplasia within epidermoid metaplasia with negative margins. Conclusions Esophageal epidermoid metaplasia may increase the risk of squamous cell carcinoma. There are no consensus recommendations regarding its management with previous described strategies including surveillance and eradication with radiofrequency ablation and band mucosectomy. ESD for epidermoid metaplasia has not been described; however, given the overall efficacy, efficiency, safety and now widespread availability of this technique a primary ESD approach should be considered. Funding Agencies None

Double-Tunnel Technique Was Similar to Single-Tunnel Technique in Clinical, Imaging and Functional Outcomes for Medial Patellofemoral Ligament Reconstruction: A Randomized Clinical Trial

This study aimed to compare the clinical, functional, and imaging outcomes of single-tunnel (ST) and double-tunnel (DT) techniques for medial patellofemoral ligament (MPFL) reconstruction. Ninety-four patients with recurrent patellar instability were randomly divided into 2 groups, receiving either ST or DT MPFL reconstruction. Lateral reticulum release (LRR) and tibial tuberosity (TT) transfer were performed as combined procedures when necessary. Preoperative and postoperative clinical characteristics (symptoms and episodes of redislocation), functional outcomes (Kujala, Lysholm, Tegner, IKDC, and KOOS score), and radiological measurements (congruence angle, patellar tilt angle, lateral patellar angle, and lateral patellar translation) were analyzed. The analysis included data from 90 patients with 48 patients in the ST group and 42 patients in the DT group. Patients were followed up for a mean period of 37.8 (range: 27-50) months in the ST group and 38.6 (range: 25-53) months in the DT group. Forty-three patients in the ST group and 40 patients in the DT group received combined TT transfer, and all patients underwent LRR. At thelatestfollow-up, 1 patient in ST group experienced redislocation, while no patient in the DT group sustained clinical failure (P= .347). Imaging measurements decreased significantly to the normal range postoperatively. No significant difference was noted between the postoperative radiological results of the 2 groups. All clinical scores significantly improvedpostoperatively,and no significant difference was observed between the 2 groups except for the higher Lysholm score (P= .031), KOOS symptoms score (P= .021) and KOOS knee-related quality of life score (P= .043) in the DT group. Both techniques could equally mitigate the patellar lateral translation or redislocation. Our results demonstrate several significant differences in functional outcomes that favored DT MPFL reconstruction but no difference in clinical failure rates and radiological results between ST and DT MPFL reconstruction. Level I, randomized clinical trial.

Paper 17: Optimal Tibial Tunnel Placement for Medial and Lateral Meniscal Root Repair in the Setting of Multiligament Reconstructions of the Knee

Objectives:Although the risk of tibial tunnel convergence in the setting of multiligament reconstruction has been reported in the literature, the risk of tunnel convergence in the setting of posterior cruciate ligament (PCL), anterior cruciate ligament (ACL), and medial and lateral meniscal root repair has not been defined. The purpose of this study was to examine the risk of tunnel convergence and to determine optimal tunnel placement for ACL and PCL reconstruction performed in conjunction with posterior medial and lateral meniscal root repairs in the proximal tibia.Methods:Three-dimensional tibial models were created using computed tomography scans of twenty cadaveric specimens. After determining optimal tunnel entry and exit points for ACL and PCL reconstructions, and medial and lateral meniscal root repair on the models, Mimics software was used to create root tunnels. The meniscal root repair tunnels were then re-oriented to be parallel to the ACL tunnel. The initial and re-oriented configurations are illustrated in Figure 1. Tunnel convergence risk was analyzed with single and double tunnel techniques in both case scenarios.Results:There were no cases of convergence between the ACL and medial meniscal root tunnels in any of the configurations. The greatest distance between the tunnels was achieved with the single tunnel technique in parallel orientation (12.09 ± 2.78 mm). All specimens demonstrated convergence between the ACL and lateral meniscal root tunnels when the sagittal plane entry was not taken into consideration and only the anatomic root attachment was accounted for, for single and double tunnel techniques, but no convergence was seen between these tunnels with the parallel orientation in the sagittal plane. Figure 2 illustrates the reduction in the convergence risk when the meniscal root tunnels are reoriented as parallel to the ACL tunnel. There were no cases of convergence between the PCL and medial meniscal root tunnels in the original orientation, but 2/20 specimens demonstrated convergence in the parallel orientation with the double tunnel technique and no cases of convergence in the single tunnel technique. The PCL and lateral meniscal root tunnels did not demonstrate convergence in any configuration. Table 1 demonstrates the mean, minimum and maximum distances of each tunnel configuration as well as the number of cases where the distance between tunnels was <2mm. A summary of the preferred tunnel configurations for each setting, ranked by greatest tunnel distance conferred and cases of convergence, is reported in Table 2.Conclusions:There is a high risk of convergence between ACL and posterior meniscus root tunnels. Re-orienting meniscal root tunnels parallel to ACL tunnels may help reduce this risk. When PCL reconstruction is performed with ACL reconstruction and medial and lateral meniscal root repair, the single tunnel root repair technique may pose less risk over the double tunnel technique to prevent tunnel convergence between the meniscal root repair and PCL tunnels in the tibia.Figure 1. Illustration of the reconstruction of the tunnels. (A) Initial orientation where the meniscal root tunnels’ entry points on the anteromedial aspect of the tibia were created above the ACL tunnel. (B) The meniscal root tunnels re-orientated and were placed parallel to that of the ACL and aimed to exit at the anatomic attachment of the posterior roots of the meniscus. (Gold guide for the creation of the ACL tunnel and silver guide for the creation of the meniscal root tunnel)

CT Derived Three Dimensional Modeling to Facilitate Minimally Invasive HVAD to HeartMate3 Left Ventricular Assist Device Exchange

<h3>Introduction</h3> The optimal surgical technique for HVAD to HeartMate 3 left ventricular assist device (LVAD) exchange will be patient dependent. We report a successful minimally invasive approach. <h3>Case Report</h3> Case: A 33-year-old woman with Adriamycin induced cardiomyopathy status post destination therapy HVAD in 2006 developed progressive alarms. Imaging revealed a large left ventricular (LV) thrombus attached to the inflow cannula. An elective HVAD to HeartMate 3 exchange was considered. Pre-operative planning: CT imaging was used to generate a three dimensional (3D) model of the heart and HVAD (A). To aid in planning both new device placement and the anastomosis between the HVAD and HeartMate 3 outflow grafts, a 3D model was generated (B). Surgical description: A left thoracotomy and 5th rib resection was used to access the HVAD and LV apex (C). The femoral vessels were cannulated for cardiopulmonary bypass and the heart was minimally manipulated. The HVAD pump, apical cuff, and exposed driveline were removed and LV clot evacuated. The HeartMate 3 apical cuff was secured to the LV apex and the pump placed in standard position (D). The HeartMate 3 (14mm) outflow graft was anastomosed to the retained HVAD (10mm) outflow graft by beveling the HVAD outflow graft (E, F). The HeartMate 3 driveline was then tunneled out of the left upper abdominal quadrant using a double tunnel technique. The thoracotomy was then closed in a standard fashion. <h3>Summary</h3> Outcome: The total bypass time was 1 hour and 20 minutes. She arrived to the intensive care unit on low dose epinephrine and vasopressin, which were rapidly weaned off. She required a total of 2 packed red blood cell transfusions. She was extubated on post-operative day 3 with normal hemodynamics and intact end organ function. She was eventually discharged in stable condition. 3D modeling was invaluable in preprocedural planning and final outcomes.

Optimal Tibial Tunnel Placement for Medial and Lateral Meniscus Root Repair on the Anteromedial Tibia in the Setting of Anterior and Posterior Cruciate Ligament Reconstruction of the Knee

Background: Although the risk of tibial tunnel convergence in the setting of multiligamentous reconstruction has been reported in the literature, the risk of tunnel convergence in the setting of posterior cruciate ligament (PCL), anterior cruciate ligament (ACL) reconstruction and medial and lateral meniscus root repair has not been defined. Purpose: To examine the risk of tunnel convergence and to determine optimal tunnel placement for ACL and PCL reconstruction performed in conjunction with posterior medial and lateral meniscus root repairs on the anteromedial proximal tibia. Study Design: Descriptive laboratory study. Methods: Three-dimensional (3D) tibial models were created using computed tomography scans of 20 cadaveric specimens. After determining optimal tunnel entry and exit points for ACL and PCL reconstructions, and medial and lateral meniscus root reattachment to the anatomic footprints, we used image processing software to create root tunnels over the anteromedial tibia on the tibial models. ACL and PCL tunnels were kept constant. The meniscus root repair tunnels were then reoriented to match the angle of the ACL tunnel, making both tunnels parallel in the sagittal plane. Tunnel convergence risk was analyzed by identifying the shortest 3D distance between tunnel axes and subtracting the radius of each tunnel from this distance for single- and double-tunnel repair techniques in both case scenarios. Results: All specimens demonstrated convergence between the ACL and lateral meniscus root tunnels when the root tunnel’s entry was created proximal to the ACL tunnel’s entry for single- and double-tunnel techniques, but no convergence was seen between these tunnels using the parallel orientation in the sagittal plane. There were no cases of convergence between the ACL and medial meniscus root tunnels in any of the configurations. The greatest distance between the ACL and medial meniscus root tunnels was achieved using the single-tunnel technique in parallel orientation (12.1 ± 2.8 mm). There were no cases of convergence between the PCL and medial meniscus root tunnels in the original orientation; however, 2 of 20 specimens demonstrated convergence using the parallel orientation with the double-tunnel technique, and there were no cases of convergence using the single-tunnel technique. The PCL and lateral meniscus root tunnels did not demonstrate convergence in any configuration. Conclusion: There was a high risk of convergence between ACL and posterior meniscus root tunnels when all the tunnels were created on the anteromedial tibia. Reorienting meniscus root tunnels parallel to ACL tunnels may help reduce this risk. There is increased risk of tunnel convergence with root repairs in cases of bicruciate reconstructions, and therefore a double-tunnel root repair technique should be used with caution. Clinical Relevance: To avoid tibial tunnel convergence when performing ACL and PCL reconstruction with medial and lateral meniscus root repair, surgeons should reorient the meniscus root repair tunnels to be parallel on the sagittal plane to the ACL tunnel to decrease the risk of convergence. In cases of bicruciate ligament reconstruction, use of the double-tunnel technique requires caution to avoid convergence risk with the PCL tunnel.

Double tunnel technique reduces technical failure during POEM in cases with severe submucosal fibrosis.

Background and study aims Submucosal fibrosis (SMF) is one of the major reasons for technical failure during per-oral endoscopic myotomy (POEM). In this study, we aimed to evaluate the impact of double tunnel technique (DT-POEM) on the technical success of POEM in cases with severe SMF. Patients and methods Data from patients with achalasia in whom SMF was encountered during POEM from Jan 2013 to Jan 2020 at our center were retrospectively evaluated. The technical success and adverse events (AEs) were analyzed and compared between cases with SMF who underwent POEM via single tunnel versus DT-POEM technique. Results A total of 1,150 patients underwent POEM during the study period. There were 14 technical failures (1.2 %). SMF and severe SMF was found in 104 (9 %) and 21 (1.8 %) patients, respectively. The majority of patients (17, 80.9 %) with severe SMF had type I achalasia. Overall, technical failures occurred in 14 cases (1.2 %) and severe SMF resulted in the majority of the technical failures (10, 71.4 %). DT-POEM was utilized in 11 cases (52.4 %) with severe SMF. The median procedure time with DT-POEM was 150 minutes (85–210). There were no major AEs and DT-POEM was technically successful in all the patients. The technical success of POEM in cases with SMF improved after the adoption of the double tunnel technique (98.4 % vs 68.3 %, P = 0.0001). Conclusions Severe SMF is the most common reason for technical failure during POEM. DT-POEM improves the technical success rates of POEM in patients with severe SMF.

Single-tunnel and double-tunnel medial patellofemoral ligament reconstructions have similar clinical, radiological and functional results.

The aim of the present study was to evaluate the clinical, radiological and functional results of patients underwent single-tunnel (ST) and double-tunnel (DT) medial patellofemoral ligament(MPFL) reconstructions with hamstring autograft following recurrent patella dislocation prospectively in a single institution. From 2013 to 2017, 80 patients with symptomatic recurrent patellar dislocation or instability were randomly divided into 2 groups for MPFL reconstruction with ST technique or DT technique and evaluated prospectively. In the ST group, there were 20 male and 20 female with a median follow-up of 46.5months (range 24-74). The median age was 15years (range 10-28). In the DT group, there were 18 male and 22 female with a median follow-up of 40months (range 24-74). The median age was 19years (range 14-29). Clinical scores (Kujala score, Lysholm score, Tegner score and IKDC score) and radiological measurements (congruence angle and patellar tilt angle) of the patients were evaluated preoperatively and at postoperative 24th month. Isokinetic dynamometric tests were performed at postoperative 24th month and the difference between the operated leg and the non-operated leg was found as a percentage deficit. There were no postoperative complications, redislocation or subluxation in any patient. Kujala, Lysholm, Tegner and IKDC scores were better and statistically significant postoperatively in both groups (p < 0.05). However, there was no statistically significant difference between the groups (n.s.). The congruence angle and patellar tilt angle were found to be returned to normal values postoperatively, but there was no statistically significant difference between the groups (n.s.). There was no statistically significant difference between the two groups in isokinetic dynamometric tests performed as 60° flexion, 60° extension, 180° flexion and 180° extension (n.s.). The present study is the first that compared the clinical, radiological and functional results of the ST and DT techniques to date. Regardless of the number of the tunnels, similar results were obtained in ST and DT reconstruction using transpatellar tunnel technique. Level I.

Loosening of Transtibial Pullout Meniscal Root Repairs due to Simulated Rehabilitation Is Unrecoverable: A Biomechanical Study

To determine whether meniscal root repairs recover from displacement due to rehabilitative loading. Transtibial pullout repairs of the posteromedial meniscal root were performed in 16 cadaveric ovine knees. Single- and double-tunnel repairs using the 2-simple suture technique were cyclically loaded in tension to 10,000 cycles, allowed to rest, and loaded in tension again. Paired differences in displacement with rest were recorded to evaluate recoverability. Displacement of repairs at cycles of interest was recorded, and the response of repairs to 10,000 cycles was assessed. All outcomes were not significantly different between the single- and double-tunnel techniques; therefore, the results were pooled. The difference in displacement between the first cycle and the first cycle after rest was 1.59 ± 0.69mm. Repair displacement did not reach an equilibrium within 10,000 cycles and instead resulted in a steady increase in displacement of 0.05 ± 0.02mm per additional 1,000 cycles. Sutures macroscopically began to cut out of the meniscus in both single- and double-tunnel repairs. This study showed that significant, unrecoverable loosening from rehabilitative loading occurred in single- and double-tunnel meniscal root repairs. Root repairs also gradually displaced with continued loading instead of reaching an equilibrium displacement after 10,000 cycles. This progressive, unrecoverable loosening needs to be studied further to better understand the resultant impact on knee mechanics. In addition, the quality and quantity of meniscal root repair healing at the time of rehabilitation should be studied to determine how susceptible patients are to repair loosening. Rehabilitative loading caused unrecoverable and progressive loosening of root repairs, showing the importance of healing before loading. Investigations on the effects of loosening on mechanics and the quality of repair healing at weight bearing are necessary to better understand the clinical implications.

Y-reconstruction could be better for ACL reconstruction in knee hyperextension versus double-bundle double-tunnel technique: a retrospective comparative study of 56 patients

To compare the clinical outcomes of double-bundle (DB) single-tibial tunnel technique and double-tunnel technique for ACL reconstruction in patients with knee hyperextension. Defined as having constitutional hyperextension of greater than 10°, 56 patients with knee hyperextension who underwent ACL reconstruction were included in this study. To exclude concomitant lesions, preoperative magnetic resonance imaging (MRI) was performed in all knees. 24 patients (Group A) were treated with the anatomic DB/single-tibial tunnel ACL reconstruction and 32 patients (Group B) were treated with DB/double-tibial tunnel ACL reconstruction, all the included patients had knee hyperextension. Clinical results were evaluated by the extension angle, ROM, IKDC 2000 subjective score, rotational stability, pivot-shift test and anterior-posterior translation test before the operation and at the end of follow-up. MRI scan of the knee positioned in full extension was performed after 6 months post-operation. Location of tibial tunnels and graft signal intensity were assessed according to the MRI. Postoperative extension deficit was detected in Group B, ROM of the injured knee in Group A was from extension angle 8.91 ± 3.16° to flexion angle 115.58 ± 10.53°. ROM of the injured knee in Group B was from extension angle - 2.13 ± 5.88° to flexion angle 119.25 ± 12.63°. Flexion angles of two groups did not show any significant difference (p = 0.24), while extension angles were quite different (p < 0.0001). Group A was slightly higher than Group B in IKDC subjective scores, but without significant difference (Group A 45.1 ± 6.5, Group B 42.4 ± 4.8, p = 0.09). There was no significant difference between two groups in pivot-shift test. Post-operational MRI showed more anterior located tibial tunnel and higher graft signal intensity in Group B when compared with Group A. One patient in the Group B had ligament retear, and required revision surgery. DB/single-tibial tunnel technique restored the knee stability and overcame the shortcomings (such as knee extension deficit and graft impingement) of DB/double tibial tunnel, which might be more suitable for ACL reconstruction in knees with hyperextension. Level II to III.

Clavicle Fracture after Coracoclavicular Ligament Reconstruction: A Biomechanical and Finite Element Evaluation of Clavicle Fracture Risk

Objectives:Biomechanical testing supports anatomic reconstruction for high-grade acromioclavicular injuries to achieve improved stability, however, clavicle fractures have been reported following reconstruction. Thus, this study used laboratory experiments and finite element models to investigate the influence of tunnel parameters on the clavicle biomechanical performance.Methods:Composite synthetic clavicles were subjected to four-point bending on a servohydraulic load frame. Two established surgical techniques were compared; a single 3 mm tunnel technique and a double 6 mm tunnel technique. Finite element (FE) models were validated against experimental findings. Subsequent FE models explored a broad range of tunnel parameters to determine their biomechanical consequences.Results:The single tunnel (3 mm) specimens exhibited a stiffness of 19.9 ± 1.55 Nm2 and failed at 686 ± 45.2 N through the tunnel. The double tunnel technique exhibited a stiffness of 15.8 ± 1.18 Nm2 and failed at 390 ± 31.7 N through the medial tunnel. In FE models of the experiments (Fig. 1), the double tunnel technique has 69% of the strength of the single tunnel (vs 57% in the experiments) and failure was predicted at the medial tunnel. In 200 variations of tunnel configuration, the double tunnel technique exhibited increased stress concentration relative to a single tunnel. Larger tunnels exhibited higher stresses than smaller tunnels. Fig. 1: FE models exhibit greater stress concentration of the double 6 mm tunnel (right) technique compared to the single 3 mm tunnel (left) and technique.Conclusion:Experimental and FE results demonstrate that the double 6 mm tunnel reconstruction has a higher stress concentration than the single 3 mm tunnel technique when subjected to four-point bending. The validated FE model supports the use of small tunnels and suggests that a double tunnel configuration may have biomechanical disadvantages that must be weighed against the perceived advantages of “anatomic” reconstruction.

Endoscopic submucosal dissection with double-tunnel technique for en bloc resection of large rectal laterally spreading tumor.

Endoscopic submucosal dissection with double-tunnel technique for en bloc resection of large rectal laterally spreading tumor.

Effect of Coracoid Drilling for Acromioclavicular Joint Reconstruction Techniques on Coracoid Fracture Risk: A Biomechanical Study

To biomechanically compare the stability of the coracoid process after an anatomic double-tunnel technique using two 4-mm drill holes or a single-tunnel technique using one 4-mm or one 2.4-mm drill hole. For biomechanical testing, 18 fresh-frozen cadaveric scapulae were used and randomly assigned to one of the following groups: two 4-mm drill holes (group 1), one 4-mm drill hole (group 2), or one 2.4-mm drill hole (group 3). After standardized coracoid drilling, load was applied to the conjoined tendons at a rate of 120 mm/min and ultimate failure load, along with the failure mode, was recorded. There was no significant difference between groups regarding load to failure. Mean load to failure in group 1 was 392 N; group 2, 459 N; and group 3, 506 N. The corresponding P values were .55, .74, and .20 for group 1 versus group 2, group 2 versus group 3, and group 1 versus group 3, respectively. However, the failure mode for the group with one 4-mm drill hole and the group with two 4-mm drill holes was coracoid fracture, whereas the group with one 2.4-mm drill hole showed 5 tears of the conjoined tendons and only 1 coracoid fracture (P= .015). Although there was no significant difference regarding load-to-failure testing between groups, the failure mechanism analysis showed that one 2.4-mm drill hole led to less destabilization of the coracoid than one or two 4-mm drill holes. Techniques with small, 2.4-mm drill holes might decrease the risk of severe iatrogenic fracture complications.

Double tunnel technique for the LVAD driveline: improved management regarding driveline infections

A driveline exit site infection is a serious and common complication in long-term left ventricular assist device (LVAD) support. To reduce the incidence and severity of late driveline infections, we modified our surgical technique (double tunnel), and compared it to the conventional short and straight driveline tunnel technique (conventional). We analyzed 43 consecutive patients (37 HeartMate II; 6 Ventrassist) regarding late onset driveline exit site infections after using the surgical driveline tunnel technique after successful LVAD implantation. Of these 43 patients, 11 were treated with the conventional short and straight driveline tunnel technique (conventional), while 32 patients were treated with the modified long subfascial, C-shaped technique (double tunnel). We observed slightly fewer superficial driveline exit site infections in the double tunnel group, even though the difference was not statistically significant (0.638 vs. 1.148 infections/1,000 patient-days; P = 0.22). There were also insignificantly fewer surgical interventions because of exit site infections in the double tunnel group (0.159 vs. 0.581 revisions/1,000 patient-days; P = 0.18). The double tunnel technique offers more surgical options in the case of driveline exit site infections. Due to the long subfascial tunnel, the infected site can be separated from the new driveline exit site, and vacuum-assisted closure therapy can be applied to the infected area. In conclusion, we recommend using the double tunnel driveline technique because of the low infection rate and better treatment options in the case of driveline exit site infection.

MPFL reconstruction

Lecture 6Primary patellofemoral dislocations are common. It results from quadriceps contraction across a flexed, valgus knee with the weightbearing tibia externally rotated compared to the femur. The dislocation usually reduces...

Deep driveline infections are prevented by surgical double tunnel technique in patients with LVAD

Objectives: Late onset driveline infections are a serious problem in patients treated with intrathoracic cardiac assist devices. We hypothesized that a long subfascial, C shaped course of the driveline (double tunnel) could reduce the incidence and severity of late driveline infections compared to the conventional short and straight driveline tunnel (conventional).

Anatomical transverse patella double tunnel reconstruction of medial patellofemoral ligament with a hamstring tendon autograft for recurrent patellar dislocation

The purpose of this study was to describe our transverse patella double tunnel technique to reconstruct the medial patellofemoral ligament (MPFL) with a hamstring tendon autograft in patients who suffered recurrent dislocation of the patella, and to evaluate the intermediate-term outcomes of reconstruction treatment. Fifty-nine consecutive knees (52 patients) with recurrent dislocation of the patella without marked predisposing anatomic abnormalities and radiographically documented moderate/severe osteochondral lesions were included in the study. Outcomes were assessed with physical and radiographic examination, the Kujala and the modified Cincinnati scores preoperatively and postoperatively at 3, 6, 12, 36, 60 and 84months. There were 19 male and 33 female patients with up to 7.1-year follow-up (mean 5.7years). The mean age was 24.3years. A comparison of preoperative scores with those obtained at most recent follow-up revealed a significant improvement for all outcomes measured: range of motion (30±2° vs. 125±5°, P<0.01), the mean Kujala scores (41.4 vs. 82.6, P<0.001), the mean modified Cincinnati scores (50.6 vs. 88.7, P<0.01), the mean congruence angle (12.2° vs. -2.4°, P<0.01) and the mean tilt angle (11.4° vs. 8.4°, P<0.05). No recurrent episodes of dislocation or subluxation were postoperatively reported, although there were seven knees with an occasional unstable feeling without redislocation. MPFL reconstruction with the double-transverse tunnels technique is safe and effective in patients of all ages, without marked predisposing anatomic abnormalities and moderate/severe osteochondral lesions, who suffered recurrent dislocation of the patella.

Stiffer Fixation of the Tibial Double-Tunnel Anterior Cruciate Ligament Complex Versus the Single Tunnel: A Biomechanical Study

The primary objective of this study was to evaluate the difference in graft pullout forces, stiffness, and failure mode of double-bundle anterior cruciate ligament (ACL) reconstruction of the tibial insertion by use of a single tunnel compared with a double-tunnel technique with interference screw fixation. ACL reconstruction on the tibial side was performed on 40 fresh-frozen porcine knees (mean bone mineral density of 0.64 g/cm(2) measured by dual-energy x-ray absorptiometry scan), randomly assigned to the single- or double-tunnel group. Interference screw fixation of the soft-tissue graft was used for both types of tibial reconstruction. Maximum failure load, stiffness, and failure mode were recorded. There was no significant difference in maximum failure load between the single-tunnel group (400 +/- 26 N) and double-tunnel group (440 +/- 20 N). Stiffness of the tibial tunnel complex was significantly higher in the double-tunnel group (76 +/- 3 N/mm) than in the single-tunnel group (62 +/- 4 N/mm) (P = .013). All but 2 grafts (38 of 40) failed by slippage of the tendon past the interference screw. There was significantly stiffer fixation of the tibial double-tunnel ACL complex when compared with the single tunnel. Our study did not show a different failure mode for the double-tunnel reconstruction compared with the single-tunnel reconstruction. This study shows a biomechanical advantage with no potential deleterious side effects for fixation of the ACL with a double-tunnel technique on the tibial side.