Anchor Placement Research Articles

Optimal Position of the Bone Anchor for the Internal Brace Suspensionplasty Technique for Thumb Basal Joint Arthroplasty

Ligament reconstruction and tendon interposition is a common technique for thumb basal joint arthroplasty. Recently, a variation of this technique, a suture suspensionplasty, has been introduced. The goal of our study was to assess the optimal position of the bone anchor in the thumb metacarpal. We hypothesized that an anchor placed in the radial aspect of the thumb metacarpal base would provide improved stability and resist subsidence more effectively than an ulnar-based thumb anchor. Eight fresh-frozen cadaver arms were imaged fluoroscopically in anteroposterior and lateral views centered over the thumb carpometacarpal joint before and after trapeziectomy and after the placement of radial-based and ulnar-based bone anchors. The intermetacarpal angle between the thumb and index metacarpals was measured on all images after the application of a standard force. Radial abduction, opposition, subsidence, palmar abduction, and adduction were measured. Subsidence was calculated as the percentage loss of the trapezial space. Both radially and ulnarly placed internal brace constructs allowed more radial abduction, opposition, and palmar abduction than the pretrapeziectomy constructs. They both also reduced subsidence by approximately 20% to 29% compared with the posttrapeziectomy constructs. Comparing radial to ulnar constructs, motion and subsidence were similar. There was immediate stability of the thumb with respect to axial load and subsidence after anchor placement, and this was independent of the anchor position. The position of the bone anchor in the thumb metacarpal base did not affect the range of motion. Although the device can limit subsidence, it does not appear to restrict any range of motion of the thumb, irrespective of anchor position. This cadaver study can help hand surgeons understand the effect of positioning of bone anchors when performing a specific suture suspensionplasty technique.

Individual computer-assisted 3D planning for placement of auricular prosthesis anchors in combination with an implantable transcutaneous bone conduction hearing device in patients with aural atresia.

The simultaneous implantation of the Bonebridge (MED-EL, Innsbruck, Austria), asemi-implantable active transcutaneous bone conduction hearing device and anchors for auricular prostheses can be challenging as both implants contain magnets and compete for the narrow space in the designated implantation area. Apreoperative planning tool (virtual surgery) was used with individual 3D computer models of the skull and implants for finding optimal implant positions for both the floating mass transducer (FMT) and the anchors for the auricular prosthesis. The interaction between the magnetic prosthesis anchors and the FMT was measured by means of static magnetic forces. A retrospective data analysis was conducted to evaluate the surgical and audiological outcome. Between 2014 and 2021, a3D planning of a simultaneous implantation of the Bonebridge with auricular prosthesis anchors was conducted on 6 ears of 5 patients (3males, 2females; age range 17-56years). The individual preoperative planning was considered very useful for the optimal placement of bone anchors in combination with the Bonebridge. Audiological data showed aclear benefit for hearing 3months and > 11months after implantation. No adverse interactions between the magnetic prosthesis anchors and the FMT were observed. In two patients, revision surgery was carried out due to skin inflammation or wound healing problems. No long-term complications were observed 3-5 years after surgery. Preoperative 3D planning represents a clear benefit for the simultaneous audiological and esthetic rehabilitation using the Bonebridge and anchors for auricular prostheses.

Individual computer-assisted 3D planning for placement of auricular prosthesis anchors in combination with an implantable transcutaneous bone conduction hearing device in patients with aural atresia. German version

The simultaneous implantation of the Bonebridge (MED-EL, Innsbruck, Austria), asemi-implantable active transcutaneous bone conduction hearing device and anchors for auricular prostheses can be challenging as both implants contain magnets and compete for the narrow space in the designated implantation area. Apreoperative planning tool (virtual surgery) was used with individual 3D computer models of the skull and implants for finding optimal implant positions for both the floating mass transducer (FMT) and the anchors for the auricular prosthesis. The interaction between the magnetic prosthesis anchors and the FMT was measured by means of static magnetic forces. A retrospective data analysis was conducted to evaluate the surgical and audiological outcome. Between 2014 and 2021 a3D planning of a simultaneous implantation of the Bonebridge with auricular prosthesis anchors was conducted on 6 ears of 5 patients (3males, 2females; age range 17-56years). The individual preoperative planning was considered very useful for the optimal placement of bone anchors in combination with the Bonebridge. Audiological data showed aclear benefit for hearing 3months and > 11months after implantation. No adverse interactions between the magnetic prosthesis anchors and the FMT were observed. In two patients, revision surgery was carried out due to skin inflammation or wound healing problems. No long-term complications were observed 3-5 years after surgery. Preoperative 3D planning represents a clear benefit for the simultaneous audiological and esthetic rehabilitation using the Bonebridge and anchors for auricular prostheses.

Ultrasound-Guided Anterior Talofibular Ligament Repair With Augmentation Can Restore Ankle Kinematics: A Cadaveric Biomechanical Study.

Background:Anterior talofibular ligament (ATFL) repair of the ankle is a common surgical procedure. Ultrasound (US)-guided anchor placement for ATFL repair can be performed anatomically and accurately. However, to our knowledge, no study has investigated ankle kinematics after US-guided ATFL repair.Hypothesis:US-guided ATFL repair with and without inferior extensor retinaculum (IER) augmentation will restore ankle kinematics.Study Design:Controlled laboratory study; Level of evidence, 4.Methods:A 6 degrees of freedom robotic testing system was used to apply multidirectional loads to fresh-frozen cadaveric ankles (N = 9). The following ankle states were evaluated: ATFL intact, ATFL deficient, combined ATFL repair and IER augmentation, and isolated US-guided ATFL repair. Three loading conditions (internal-external rotation torque, anterior-posterior load, and inversion-eversion torque) were applied at 4 ankle positions: 30° of plantarflexion, 15° of plantarflexion, 0° of plantarflexion, and 15° of dorsiflexion. The resulting kinematics were recorded and compared using a 1-way repeated-measures analysis of variance with the Benjamini-Hochberg test.Results:Anterior translation in response to an internal rotation torque significantly increased in the ATFL-deficient state compared with the ATFL-intact state at 30° and 15° of plantarflexion (P = .022 and .03, respectively). After the combined US-guided ATFL repair and augmentation, anterior translation was reduced significantly compared with the ATFL-deficient state at 30° and 15° of plantarflexion (P = .0012 and .005, respectively). Anterior translation was not significantly different for the isolated ATFL-repair state compared with the ATFL-deficient or ATFL-intact states at 30° and 15° of plantarflexion.Conclusion:Combined US-guided ATFL repair with augmentation of the IER reduced lateral ankle laxity due to ATFL deficiency. Isolated US-guided ATFL repair did not reduce laxity due to ATFL deficiency, nor did it increase instability compared with the intact ankle.Clinical Relevance:US-guided ATFL repair with IER augmentation is a minimally-invasive technique to reduce lateral ankle laxity due to ATFL deficiency. Isolated US-guided ATFL repair may be a viable option if accompanied by a period of immobilization.

Optimization of Anchor Placement in TPoS MEMS Resonators: Modeling and Experimental Validation

In this paper, a semi-analytical model is derived to calculate the anchor loss of TPoS resonators operating in higher-order length extensional modes. This model provides valuable insights on the effect of order, device dimensions, position and number of anchors on the quality factor (Q) of these resonators. Results from this model are in close agreement with the FEM simulations. The optimum position, dimension, and the number of anchors to deliver the highest Q are also discussed. Predictions of the model are validated through characterization of TPoS resonators fabricated to operate at a resonant frequency of around 1 GHz with different number of anchor pairs and position. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$23^{rd}$ </tex-math></inline-formula> order resonator with a W/L ratio of 1.5 with three pairs of anchors placed at positions suggested by the model gave a loaded Q of 4431, which is 65% more than the conventional case where anchors are uniformly placed towards the edge, and also an improvement in the insertion loss by 5.5 dB compared to the latter. For resonators where the anchor loss is predominant, our results show that the performance can be improved by placing the anchors at the optimum position, closer to the middle of the resonator than the conventional scheme where anchors are uniformly placed towards the edge.

Treatment of avulsion fracture of inferior pole of patella with improved angle of anchor and double pulley technique

To evaluate the angle of modified anchor nail placement and the curative effect of double pulley technology for the treatment of extreme avulsion fracture of lower patella. From December 2015 to December 2018, a total of 22 patients(10 males and 12 females) with avulsion fracture of the inferior pole of patella were retrospectively analyzed. The average age was (44.00±15.24) years old(range, 19 to 70 years). All patients were treated with modified anchor angle and double pulley technique. The range of motion(ROM) and Bostman score system were used to evaluate the functional recovery of knee joint. All 22 cases were followed up with an average of (30.86±8.00) weeks (18 to 46 weeks). At the last follow-up, ROM of the affected knee was (130.82±4.69) °, and the contralateral knee was (133.23 ± 3.15) °, there was no significant difference between two groups (P>0.05). The average Bostman score was (28.45±1.41) scores, 18 cases were excellent results, 4 cases were good. Improved anchor placement angle and double pulley technique for treatment of extreme avulsion fracture of lower patella is easy to operate, with satisfactory curative effect and good recovery of knee joint function.

O099 Position and number of anchors in hip arthroscopy labrum repair: a systematic review

Abstract Introduction Hip labral tears are reported in 22–55% of patients with hip or groin pain. Operative treatment is necessary for most cases, via hip arthroscopy with the use of suture anchors. This systematic review aims to determine the optimal number and position of anchors in hip labral repair. Methods Pubmed, Ovid &amp; Embase were searched, and 2 researchers independently screened the 1,304 results. Outcome measures such as procedures performed, number &amp; (clockface) position of anchors, failure &amp; articular involvement of anchors were extracted. Results 5 studies were included in the analysis: 1 Cross-Sectional Study (1645 Hips, mean age (MA):33.7 years), 3 Retrospective case studies (491 hips, MA:31.0) and 1 Controlled Cadaveric study (32 cadaveric hips, MA:62.7). Chi-squared statistical analysis of 323 hips found a significant difference (X2 (2, N = 323) = 17.88, p &amp;lt; .001) in the risk of articular involvement with the position of anchors at 11°-12° o’clock, 1°-2° and 3°-4°. There is an absolute risk reduction (ARR) of 19% with anchors positioned at 11°-12° compared to anchors positioned at 3°-4° (X2 (1, N=178) =15.79, p &amp;lt; .001) and an ARR of 12% with anchors at 1°-2° compared to anchors positioned at 3°-4° (X2 (1, N = 237) = 15.79, p &amp;lt; .0109). Additionally, by assessing 1645 operations it was found that for tears spanning &amp;gt;2 hours, a minimum of 2 anchors was placed. Conclusion Placement of anchors in the 3°-4° o’clock position carries the highest risk for articular involvement. Small diameter anchors and careful placement can be used to minimize articular injury. Preferable positions of anchors are 11°-12°, furthermore, for tears spanning over 2 hours, a minimum of 2 anchors was placed. Take-home message In Hip Arthroscopy labral repair, placement of anchors in the 3°-4° o’clock position carries the highest risk for articular involvement. Small diameter anchors and 2 hours. flexible anchor instrumentation can be used to minimize articular injury, furthermore, for tears spanning over 2 hours, a minimum of 2 anchors was placed.

Internal rotation of the shoulder in the beach chair position may increase the risk of iatrogenic suprascapular nerve injury at the spinoglenoid notch during surgical treatment for shoulder instability.

Suprascapular nerve (SN) at the spinoglenoid notch is a mobile structure which is vulnerable to iatrogenic injury from screw or guidewire penetration during shoulder surgery such as Latarjet procedure or SLAP/Bankart repairs. The primary objective is to identify the distance between posterior glenoid and SN in different shoulder abduction and rotation. The secondary objective is to identify the distance in standard lateral decubitus position. Nineteen shoulders from 10 Thiel embalmed soft cadavers were used in this study. The dissection of posterior shoulder was done to identify the SN at spinoglenoid notch. The distance between the posterior glenoid rim and the SN was measured. In beach chair position, the SN distance from six combinations of shoulder position was obtained: adduction/90° internal rotation (ADIR), adduction/neutral rotation (ADN), adduction/90° external rotation (ADER), 45° abduction/90° internal rotation (ABIR), 45° abduction/neutral rotation (ABN), 45° abduction/90° external rotation (ABER). Subsequently, the suprascapular nerve distance was measured in standard lateral decubitus position with 10lbs. longitudinal traction. In the beach chair position with the shoulder in adduction, the mean distances between the glenoid and the SN in ADIR, ADN and ADER were 15.0 ± 3.3, 19.3 ± 2.6 and 19.5 ± 3.1mm, respectively. During shoulder abduction, the mean distances when the shoulder was in ABIR, ABN and ABER were 15.2 ± 3.4, 19.4 ± 3.0 and 19.3 ± 2.6mm, respectively. The mean distance for the lateral decubitus position was 19.3 ± 2.4mm. The distance between the glenoid and SN was significantly shorter when the shoulder was positioned in internal rotation than in neutral (p < 0.001) or external rotation (p < 0.001) when compared to the same shoulder abduction position. The lateral decubitus position had comparable SN distance with the shoulder position of abduction/neutral rotation in beach chair position. The SN was closest to posterior glenoid rim if the shoulder was in internal rotation. Therefore, shoulder internal rotation must be avoided during guidewire and cannulated screw placement in the Latarjet procedure and drill bit insertion during anchor placement in SLAP/Bankart repair.

The safety and efficacy of 2 anterior-inferior portals for arthroscopic repair of anterior humeral avulsion of the glenohumeral ligament: cadaveric comparison.

Humeral avulsion of the glenohumeral ligament (HAGL) lesions are associated with shoulder instability. Arthroscopic repair of anterior HAGL lesions typically requires the placement of an anterior-inferior (5-o'clock) portal, with different variations of this portal described. The purpose of this study was to determine the efficacy of described anterior-inferior shoulder arthroscopy portals for arthroscopic anterior HAGL repair, as well as evaluate the safety of these portals with respect to the surrounding neurovascular structures. Additionally, we sought to evaluate the effect of arm adduction vs. standard abduction during anterior-inferior portal creation. HAGL lesions were created and repaired using an all-arthroscopic technique in 12 cadaveric shoulders (matched pairs). Half of the repairs were performed using a standard 5-o'clock portal, whereas the other half of the matched pairs were repaired using a medialized 5-o'clock portal. Repairs were timed, and the number of anchor pullouts was recorded. The shoulders were subsequently dissected to measure the proximity of the portal to the cephalic vein, musculocutaneous nerve, axillary nerve, and lateral cord of the brachial plexus. The average time for HAGL repair was 18.0 ± 4.6 minutes. Repair times using the medial 5-o'clock portal (19.0 ± 3.3 minutes) vs. standard 5-o'clock portal (16.2 ± 5.8 minutes) were not significantly different (P = .37). From abduction to adduction, the cephalic vein distance from the standard 5-o'clock portal increased from 4.1 ± 4.7 mm to 5.2 ± 5.4 mm (P = .02); musculocutaneous nerve distance, from 14.4 ± 9.8 mm to 18.1 ± 10.8 mm (P = .005); axillary nerve distance, from 19.2 ± 9.6 mm to 19.8 ± 9.2 mm (P= .12); and distance of the lateral cord of the brachial plexus, 13.8 ± 6.6 mm to 16.7 ± 6.4 mm (P = .0006). The arm abduction angle significantly affects the distance of the cephalic vein, musculocutaneous nerve, and lateral cord of the brachial plexus from the anterior-inferior portal, regardless of which portal-standard or medial 5-o'clock portal-is chosen. This portal should be created with the arm in adduction. Arthroscopic HAGL repair can be performed safely, although accurate anchor placement remains a challenge. There was no advantage to use of the medial 5-o'clock portal. With a curved guide, the standard 5-o'clock portal allows for reproducible anchor placement and is recommended for anterior HAGL repairs.

“Scopen” Scope to Open Hamstring Repair

Background: Hamstring injuries at the musculotendinous junction are relatively common. However, injuries to the proximal hamstring account for just 12% of hamstring injuries. Surgical repair of these injuries including both open and endoscopic techniques are becoming increasingly more common. Indications: Surgical intervention is generally reserved for cases with 2 or more torn tendons and at least 2 centimeters of retraction. Technique Description: The combined open and endoscopic technique utilizes direct posterior and posterolateral portals. After visualizing the posterior femoral cutaneous (PFCN) and sciatic nerves (SN), the proximal hamstring tear is identified, and the shaver is used to remove any surrounding adhesions and aid in clearing any hematoma. The ischial tuberosity is prepared using a shaver, radiofrequency ablation, and a 5.5 mm, round arthroscopic burr. Two, 4.5 mm, doubled-loaded anchors are placed into the ischium. The incision for the open portion of the case is created by incising the skin between the direct posterior and posterolateral portals. A dissection is continued down to the gluteal fascia, and the gluteal fascia is incised in line with the surgical incision. The gluteus maximus is retracted then the hamstring stump is secured with a stay suture and brought outside the surgical incision for inspection. The double-loaded sutures are passed in a running locking technique. The other suture limbs are then passed through the central aspect of the tendon and tensioned to reduce the proximal hamstring onto the prepared tuberosity. Results: Significant postoperative improvements in patient-reported outcomes have been reported for open and endoscopic repairs in isolation, but to date there are no outcomes studies on the combined “Scopen” technique. Postoperative complications may include numbness or neuropraxia, re-rupture, infection, and deep vein thrombosis (DVT). Discussion: The endoscopic portion allows an improved view and preservation of the SN and PFCN, as well as a detailed view of the ischial tuberosity for decortication and anchor placement in comparison with a purely open approach. In comparison with a purely endoscopic approach, this combined approach can be used in patients with retraction &gt;4 cm, and can also be utilized for chronic, retracted tears as well.

Paper 36: Change in Humeral Anchor Position Significantly Affects Isometry in UCL Repair: A 3-Dimensional Computer Modeling Study

Objectives:Medial ulnar collateral ligament (UCL) repair utilization is increasing in recent years, bolstered by shorter rehabilitation and satisfactory clinical outcomes. While previous literature has illustrated the importance of tunnel position on restoring graft isometry in UCL reconstruction, there remains a paucity of literature guiding anchor placement in UCL repair. Herein, we describe a 3-dimensional (3D) elbow model to measure and optimize anchor location during UCL repair.Methods:A 3D computer model of a human elbow joint was created using CT and MRI images from a single patient. The humeral and ulnar attachments of the UCL were plotted using three distinct methodologies: 1) geometric cloud mapping; 2) quantitative measurements as described by the anatomical studies by Camp et al1; and 3) Frangiamore et al2. A 3.5mm-diameter clockface was placed on each attachment site which allowed for simulation of 12 distinct, 1.75mm deviations in anchor position. The three elbow models were then ranged through 0-120 degrees of flexion at 10-degree increments, and the 3D distances were measured between the two ligament centroids. The humeral and ulnar anchors were sequentially repositioned around the clockfaces, and ligament lengths were again measured to evaluate changes in isometry. An independent t-test was performed to determine if there was a significant difference in isometry between the humeral or ulnar anchor deviations.Results:Using method 1, the UCL length at 90 degrees of elbow flexion was 26.8mm. This ligament underwent 13.6mm of total excursion for a 46.4% change in length throughout arc of motion. Method 2 produced a 19.3mm ligament that underwent 0.8mm of excursion for a 3.9% length change throughout the arc. Method 3 produced a 24.5mm ligament that underwent 2.3mm of excursion for a 9.4% length change throughout arc. Identifying ligament footprints using the quantitative anatomical measurements as described by Camp et al1 and Frangiamore et al2 produced better ligament isometry through 120 degrees of flexion (ligament length changes of 3.9% and 9.4%, respectively) when compared to using the geometric cloud technique (46.4% length change). Humeral anchor deviations produced a statistically significant increase in ligament excursion when compared to ulnar anchor deviations (p < 0.001).Conclusions:When performing UCL repair, small deviations in humeral anchor position may significantly influence graft and ligament isometry. Anchor position was most isometric while using the quantitative measurements as described in Camp et al1. Particularly when addressing detachments of the humeral footprint, surgeons should be critical of the humeral anchor position in order to restore native anatomy and optimal biomechanics.

All-Suture Anchor Repair of the Flexor Digitorum Profundus Insertion: A Biomechanical Comparison of 2 Suturing Techniques

We compared 2 suturing techniques for reattachment of the flexor digitorum profundus (FDP) via all-suture anchor. We used fresh, matched-pair, cadaveric hands. We disarticulated the fingers at the proximal interphalangeal joints, preserving the proximal FDP. We released the FDPs at their distal insertion and placed an all-suture, 1.0-mm anchor at the center of each FDP footprint. Each anchor's sutures were used to reattach each FDP using 1 of 2 techniques: group H (n= 14) via horizontal mattress; group H+ K (n= 12) via horizontal mattress with knots thrown and, with each suture tail, 3 proximal, running-locking, Krackow-type passes on the radial and ulnar FDP sides with the suture ends tied together. We excluded 2 specimens from the H+ K group because of improper anchor placement. All other fingers in both groups were individually mounted in an MTS machine for FDP loading in the following sequence for 500 cycles each: (1) to 15 N to simulate passive motion forces; (2) to 19 N for short-arc active motion forces; and (3) to 28 N for full active motion forces. Specimens that had not failed during cyclic testing were then loaded to failure. We measured FDP-to-bone gapping via a digital transducer. We defined failure as >3-mm gapping. The H+ K group had significantly less gapping during cyclic loading up to 19 N and significantly higher load to failure. The H+ K group failed exclusively at the anchor-bone level; the H group failed mostly by suture-tendon pullout. The H+ K group performed significantly better regarding cyclic and load-to-failure testing after FDP reattachment. The H+ K technique combines the benefits of horizontal-mattress tendon-to-bone apposition and Krackow-tendon locking. It converts the point of failure to the bone level rather than the suture-tendon level.

Indoor scenario-based UWB anchor placement optimization method for indoor localization

Currently, ultra-wideband (UWB)-based localization systems are attracting much attention due to their high ranging accuracy. It is well known that the relative sensor–source geometry and non-line-of-sight (NLOS) measurement can severely impact the accuracy of the location estimate. To improve the localization accuracy, we propose an anchor placement optimization method that is based on the corresponding indoor scenario. Specifically, concrete walls affect the ranging error and constrain the placement of UWB sensors. An indoor scenario modeling method is presented for generating NLOS ranging paths and dividing the search space. Furthermore, a stochastic/deterministic combination ranging model is proposed based on the through-the-wall path and Gaussian process regression technique. We propose a heuristic differential evolution algorithm for searching for an optimal anchor placement that is based on minimizing the Cramer–Rao lower bound (CRLB) and predicting the ranging error. In addition, a region division method and a region combination method are proposed for reducing the search space, optimizing anchor placement in parallel in different regions, and providing full line-of-sight (LOS) coverage regions to the greatest extent possible. Finally, field experiments demonstrate the effectiveness of the proposed indoor scenario modeling method and ranging model. The proposed indoor scenario-based UWB anchor placement method achieves decimeter-level localization accuracy. A thorough comparison confirms the localization performance improvement attributed to the proposed anchor placement method.

Ability to Retension Knotless Suture Anchors: A Biomechanical Analysis of Simulated Bankart Lesions.

Background:Knotless suture anchors are gaining popularity in arthroscopic glenohumeral labral repairs. The ability to retension knotless designs after initial anchor placement has been reported; however, no studies have quantified this claim or investigated the biomechanical consequence of retensioning.Purpose/Hypothesis:To determine whether knotless and knotted suture anchors have biomechanical or anatomic differences with regard to labral repairs and to determine whether retensioning of knotless suture anchors affects capsular tension, labral height, and capsular shift. We hypothesized that retensioning of knotless anchors would result in improved capsular tension compared with conventional knotted suture anchors.Study Design:Controlled laboratory study.Methods:A total of 18 fresh-frozen cadaveric shoulders with a mean age of 56 years were dissected to the capsule and disarticulated at the humeral capsular insertion. The scapula was potted and placed in a custom shoulder simulator to tension the capsule via braided sutures localized to the anteroinferior glenohumeral ligament. Specimens were randomized into 3 groups: (1) Knotted (KT), (2) Knotless with end retensioning (KLend), and (3) Knotless with stepwise retensioning (KLstepwise). All repairs were completed using all-suture anchors placed at the 5-, 4-, and 3-o’clock positions. KLstepwise was used to simulate an intraoperative technique. Resultant mean capsular tension under 5 mm of displacement (subfailure loading) was measured for each anchor placement and retensioning step. Labral height and capsular shift were measured using a MicroScribe digitizer.Results:The intact, defect, 1-anchor, 2-anchor, and 3-anchor tensions were not significantly different between the KT and KLend groups. For the latter, retensioning of all knotless anchors increased capsular tension by 2.1 N compared with its 3-anchor state, although this was not statistically significant (P = .081). The KLstepwise group explored an alternative method to retension the capsule using knotless anchors, with similar final capsular tensions compared with the other groups. All repairs had similar improvements in capsulolabral height and superior capsular shift.Conclusion:Knotted and knotless suture anchors provided similar overall restorations in anteroinferior glenohumeral ligament tension. However, knotless devices were capable of small but statistically insignificant improvements in capsular tension with retensioning.Clinical Relevance:Retensioning of knotless anchors allows the surgeon to tighten regions of the glenohumeral capsule that remain lax after repair.

An UWB-based indoor coplanar localization and anchor placement optimization method

An UWB-based indoor coplanar localization and anchor placement optimization method

Use of bone anchors for the treatment of partial and complete traumatic elbow luxations: A retrospective case series of three dogs

AbstractThree dogs presented with traumatic lateral elbow luxation following road traffic accidents. Concurrent injuries included skin abrasions and coxofemoral luxation. All luxations were reduced and stabilised with bone anchors through a lateral approach to the elbow joint and had an augmented or prosthetic lateral collateral ligament placed. One elbow joint was stabilised with FASTak anchor (Arthrex, Karsfeld, Germany) and two with suture anchors by IMEX bone anchor (Veterinary, Longview, TX). Reluxation occurred in one case 24 hours after discharge requiring revision surgery. Median follow‐up time for the three cases was 180 days (range: 49–2920) and the functional outcome was considered excellent in all cases as determined by veterinary assessment, clinical record reviews, owner communication and Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. In conclusion, placement of bone anchors with augmentation of the lateral collateral ligament for management of traumatic elbow luxation in dogs is a good alternative to previously reported surgical techniques.

Comparison of suture anchor penetration rate between navigation-assisted and traditional shoulder arthroscopic capsulolabral repair.

Proper placement of suture anchors is an important step in Bankart repair as improper placement can lead to failure. Concern surrounding suture anchor placement inspired the use navigation systems in shoulder arthroscopy. We aimed to demonstrate the technological advantage of using the O-arm (Medtronic Navigation, Denver, CO, USA) image guidance system to provide real-time images during portal and anchor placements in shoulder arthroscopy. Consecutive patients (from July to October 2014) who were admitted for arthroscopic capsulolabral repair surgeries were included. Ten patients were randomly enrolled in the navigation group and 10 in the traditional group. The glenoid was divided into four zones, and the penetration rates in each zone were compared between the two groups. In zone III, the most inferior region of the glenoid, the penetration rate was 40.9% in the traditional group and 15.7% in the navigation group (P = 0.077), demonstrating a trend toward improved accuracy of anchor placement with the aid of the navigation system; however, this was not statistically significant. Average surgical time in the navigation and traditional groups was 177.6±40.2 and 117.7±17.6 mins, respectively. American Shoulder and Elbow Surgeons Shoulder Scores showed no difference before and 6 months after surgery. This pilot study showed a trend toward decreased penetration rate in O-arm-navigated capsulolabral repair surgeries and decreased risks of implant misplacement; however, possibly due to the small sample size, the difference was not statistically significant. Further large-scale studies are needed to confirm the possible benefit of the navigation system. Even with the use of navigation systems, there were still some penetrations in zone III of the glenoid. This penetration may be attributed to the micro-motion of the acromioclavicular joint. Although the navigation group showed a significant increase in surgical time, with improvements in instrument design, O-arm-navigated arthroscopy will gain popularity in clinical practice.

Addressing Arthroscopic-Assisted Acromioclavicular Joint Reconstruction in the Beach Chair Position With Concomitant Labral Pathology in the Lateral Decubitus Position

High-grade Acromioclavicular (AC) injuries are complete dislocations, involving ruptures of the AC and coracoclavicular ligaments. They occur following trauma after a fall, direct-blow to an adducted arm, or indirectly by falling onto an abducted, outstretched extremity. Given this traumatic etiology, additional intra-articular pathologies can arise and may go unnoticed because of the painful and prominent AC joint (ACJ). Previous studies have evaluated patients with high-grade ACJ injuries with diagnostic arthroscopy at the time of an ACJ reconstruction. They found associated injuries to the labrum/biceps, rotator cuff, and articular cartilage. The arthroscopic-assisted ACJ reconstruction (AA-ACJR) technique has made it possible to identify the associated injuries and treat them concurrently. The previous studies have performed this reconstruction in the beach chair position (BCP) and have addressed the concomitant pathology in the same position. As opposed to the BCP, the lateral decubitus position (LDP) allows for easier application of traction to the arm and, thus, improves visualization of the glenoid, especially the inferior and posteroinferior portions. It is imperative to gain appropriate access to the inferior glenoid for anchor placement to address this component of traumatic instability. We present the technique for addressing high-grade ACJ injuries with AA-ACJR in the BCP preceded by labral repair in the LDP.

Arthroscopic Intra-Articular Repair of the Torn Subscapularis Tendon with Single Anterior Portal, Single Suture Anchor, and X-Shaped Fixation Technique.

Subscapular tendon plays an important role in shoulder joint function. With the advance of magnetic resonance imaging technology and the popularization of arthroscopic shoulder surgery, subscapularis tears have been increasingly detected. However, reduction and fixation of subscapular tendon tears appears to be technically challenging. This study aims to describe an arthroscopic intra‐articular X‐shaped fixation technique: a procedure of subscapularis tendon repair performed with the aid of a suture passer using only a single anterior portal and a single suture anchor. By incorporating the advantages of a single anterior working portal for anchor placement and tear repair, this technique provides an easier way to use suture lasso and make knots in a limited working space, and the whole procedure is minimally invasive with a short learning curve. This technique has been applied in patients with subscapularis tears involving no intraoperative or postoperative complications. Our technology offers a valuable new treatment option for subscapularis tears.

Indoor Positioning of Low-Cost Narrowband IoT Nodes: Evaluation of a TDoA Approach in a Retail Environment.

The localization of internet of things (IoT) nodes in indoor scenarios with strong multipath channel components is challenging. All methods using radio signals, such as received signal strength (RSS) or angle of arrival (AoA), are inherently prone to multipath fading. Especially for time of flight (ToF) measurements, the low available transmit bandwidth of the used transceiver hardware is problematic. In our previous work on this topic we showed that wideband signal generation on narrowband low-power transceiver chips is feasible without any changes to existing hardware. Together with a fixed wideband receiving anchor infrastructure, this facilitates time difference of arrival (TDoA) and AoA measurements and allows for localization of the fully asynchronously transmitting nodes. In this paper, we present a measurement campaign using a receiver infrastructure based on software-defined radio (SDR) platforms. This proves the actual usability of the proposed method within the limitations of the bandwidth available in the ISM band at . We use the results to analyze the effects of possible anchor placement schemes and scenario geometries. We further demonstrate how this node-to-infrastructure-based localization scheme can be supported by additional node-to-node RSS measurements using a simple clustering approach. In the considered scenario, an overall positioning root-mean-square error (RMSE) of is achieved.