Exploring Alternative Sites for Glenoid Component Fixation Through Three-Dimensional Digitization of the Glenoid Vault: An Anatomic Analysis.

INTRODUCTION: Glenoid component loosening has remained one of the most common complications for total shoulder arthroplasty. Three-dimensional modeling of the glenoid may reveal novel information regarding glenoid vault morphology, providing a foundation for implant designs that possess the potential to extend the survivorship of the prosthesis. METHODS: A three-dimensional digitizer was used to digitize the glenoids of 70 cadaveric scapulae. We identified ideal position, fit, and maximum diameter for cylinders of 5, 10, and 15 mm depths. Maximum diameter and volume were also measured at the glenoid center, and the data were compared. RESULTS: The vault region that accommodates the greatest diameter and volume for 5, 10, and 15 mm depth cylinders were identified in the postero-inferior glenoid. Across all specimens, this region accommodated a cylinder diameter that was 24.82%, 40.45%, and 50.34% greater than that achieved at the glenoid center for 5, 10, and 15 mm depth cylinders, respectively (all, P < 0.0001). The location of this site remains reliable for each cylinder depth, regardless of sex. DISCUSSION: This study presents novel findings pertaining to glenoid morphology through the analysis of a newly characterized glenoid vault region. This region has not been identified or described previously and has potential to serve as an alternative to the glenoid center for peg or baseplate fixation. Our method of vault analysis and findings may be used to guide further research regarding pathologic glenoid anatomy, providing a foundation for alternative approaches to glenoid prosthesis fixation in total shoulder arthroplasty and related procedures.

All-Epiphyseal Physeal-Sparing Anterior Cruciate Ligament Reconstructive Surgery: A Study of 3-Dimensional Modeling to Characterize a Safe and Reproducible Surgical Approach.

PURPOSE: The purpose of this study was to use 3-dimensional magnetic resonance imaging modeling of the skeletally immature knee to help characterize safe and reproducible tunnel positions, diameters, lengths, trajectories, and distances from anatomic landmarks and the physeal and articular cartilage for physeal-sparing anterior cruciate ligament (ACL) reconstructive surgery. METHODS: Magnetic resonance imaging from 19 skeletally immature knees with normal anatomy were gathered. The 3-dimensional models were created, and the relevant anatomic structures were identified. Cylinders simulating tunnel length, diameter and trajectory were superimposed onto the models, and descriptive measurements were performed. RESULTS: A safe position for the creation of an 8 mm diameter femoral tunnel was described in the lateral femoral condyle. The femoral tunnel length averaged 25.5 ± 2.6 mm. The bony entry point was located 3.8 ± 2.4 mm proximally and 12.7 ± 2.2 mm posteriorly to the lateral epicondyle. The shortest distance from the tunnel edge to the physis and femoral articular cartilage was 2.8 ± 0.7 mm and 3.7 ± 0.9 mm, respectively. The safe position for an 8 mm diameter tibial tunnel was also identified and described in the proximal tibia. The epiphyseal tibial tunnel length from the ACL footprint to the physis averaged 15.5 ± 1.6 mm. The proximal tibial epiphysis was found to accommodate a tibial crosspin measuring 63.5 ± 5.9 mm in length and 8.2 ± 1.5 mm in diameter without disrupting the physis or articular cartilage. CONCLUSIONS: Three-dimensional modeling created from magnetic resonance imaging can help define important anatomic relationships for physeal-sparing ACL reconstructive surgery in skeletally immature knees and may assist in reducing the risk of injury to local anatomic structures. CLINICAL RELEVANCE: Knowledge of the anatomic relationships in skeletally immature knees serves as a valuable reference for surgeons performing physeal-sparing ACL reconstruction surgery.

Nonhardware Subchondral Transosseous Cerclage for Displaced Comminuted Patella Fracture Repair: A Case Report.

CASE: We report a case of a 62-year-old woman who presented to our clinic with a displaced transverse comminuted patella fracture. The fracture was repaired using a subchondral transosseous suture cerclage technique which uses the dense subchondral bone to obtain an initial anatomic reduction of the articular surface, contain the comminution, and achieve union while avoiding complications associated with traditional hardware. CONCLUSION: This case illustrates the potential for the broader implementation of subchondral transosseous cerclage suture fixation techniques for patellar fractures.

Suture Tape With Broad Full-Width Core Versus Traditional Round Suture With Round Core: A Mechanical Comparison.

PURPOSE: To compare the inherent mechanical properties of suture in tape configuration with a flat, evenly distributed core to a round suture with a round core composed of the same materials. METHODS: SutureTape and FiberWire composed of equivalent materials were used to tie surgical knots. Knot height was measured. Knot security was measured at the maximum load at 1, 2, and 3 mm of displacement and at failure. Tensile strength and stiffness were measured using untied samples. RESULTS: SutureTape demonstrated superior knot security with greater ultimate load to failure (327.2 ± 15.4 N vs 257.4 ± 12.2 N; P = .002), maximum load at 1 mm of displacement (149.8 ± 18.6 N vs 108.8 ± 13.8 N; P = .001), and 2 mm of displacement (242.7 ± 38.6 N vs 181.2 ± 24.4 N; P = .008). It also demonstrated greater stiffness (5.4 ± 0.3 N/mm vs 2.8 ± 0.3 N/mm; P < .001) and tensile strength (378.8 ± 13.6 N vs 235.6 ± 4.8 N). Knot height differences (1.27 ± .11 mm vs 1.37 ± .08 mm; P = .110) and load at 3 mm of displacement (279.3 ± 42.4 N vs 225.5 ± 46.1 N; P = .062) were not statistically significant. CONCLUSIONS: During mechanical testing, SutureTape with a broad core distributed over the full width of the tape demonstrated greater knot security, ultimate load to failure, and tensile stiffness than FiberWire, a round core suture. We found no significant difference in knot stack height between the suture designs. CLINICAL RELEVANCE: The study demonstrates the superior mechanical properties of suture in tape configuration over similarly composed round suture without a significant difference in knot stack height. Suture in tape configuration has the potential to perform as well as round suture in the clinical setting.

Extra-articular, Intraepiphyseal Drilling for Osteochondritis Dissecans of the Knee: Characterization of a Safe and Reproducible Surgical Approach.

BACKGROUND: Osteochondritis dissecans (OCD) is an idiopathic focal condition affecting the subchondral bone of joints, and it is increasingly prevalent among the active young adult population. For lesions that have failed nonoperative management, transarticular drilling and extra-articular drilling are surgical options. Although the extra-articular approach preserves the articular cartilage, it is technically challenging and could benefit from a study of surgical approach. PURPOSE: To use 3-dimensional modeling of magnetic resonance imaging (MRI) scans from skeletally immature individuals to characterize safe tunnel entry points, trajectories, and distances from the physeal and articular cartilage along the course of the distal femoral epiphysis to the OCD target in their most common location of the medial femoral condyle (MFC). STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 17 MRI scans from skeletally immature patients were used to create 3-dimensional models of the knee joint. Virtual representations of an OCD lesion were placed in the lateral aspect of the MFC; cylinders simulating tunnel length, diameter, and trajectory were superimposed onto the models; and measurements were taken. RESULTS: Two safe tunnels were identified, 1 anterior and 1 posterior to the medial collateral ligament (MCL). The anterior tunnel had a diameter of 10.3 ± 1.4 mm, skin entry point of 16.9 ± 12.1 mm anterior and 7.1 ± 5.9 mm superior to the medial epicondyle, bony entry point of 12.1 ± 3.5 mm anterior and 2.4 ± 3.5 mm inferior to the medial epicondyle, and tunnel length of 31.8 ± 3.7 mm. The posterior tunnel had a diameter of 7.8 ± 1.8 mm, skin entry point of 9.4 ± 5.1 mm posterior and 26.0 ± 14.0 mm superior to the medial epicondyle, bony entry point of 8.6 ± 2.6 mm posterior and 5.1 ± 4.2 mm superior to the medial epicondyle, and tunnel length of 33.5 ± 4.5 mm. CONCLUSION: This anatomic characterization study identifies and defines 2 safe and reproducible tunnel approaches, 1 anterior and 1 posterior to the MCL, for drilling or creating tunnels to OCD lesions of the MFC in an extra-articular fashion. CLINICAL RELEVANCE: The study findings provide valuable anatomic references for surgeons performing extra-articular drilling or tunneling of OCD lesions.

A Biomechanical and Clinical Comparison of Midshaft Clavicle Plate Fixation: Are 2 Screws as Good as 3 on Each Side of the Fracture?

BACKGROUND: The standard of care for plating displaced midshaft clavicle fractures has been 6 cortices of purchase on each side of the fracture. The use of locking plates and screws may afford equivalent biomechanical strength with fewer cortices of purchase on each side of the fracture. PURPOSE: To compare the biomechanical and clinical performance of 3- versus 2-screw constructs for plating displaced midshaft clavicle fractures. STUDY DESIGN: Controlled laboratory study/cohort study; Level of evidence, 3. METHODS: Lateral fragments of simulated midshaft fractures in 10 pairs of cadaveric clavicles were randomly assigned to plate fixation with either 3 nonlocking screws or 2 locking screws. Cyclic tensile loads were applied along the long axis of the clavicle. The constructs were then loaded to failure with pullout forces applied parallel to the long axis of the screws. Additionally, clinical outcomes of patients who had midshaft clavicle fractures that were surgically repaired were retrospectively identified and compared; 21 patients were treated with 3-screw constructs and 20 with 2-screw constructs. RESULTS: Biomechanically, there were no significant differences for cyclic displacement, stiffness, yield load, or ultimate load between groups. Forces required for screw pullout were considerably higher than physiologic forces experienced by a healing clavicle in vivo. Clinically, there were no significant differences in American Shoulder and Elbow Surgeons, Constant, visual analog scale, and Single Assessment Numeric Evaluation scores; complications; or mean time to union. Additionally, we found that the plates used in the 2-screw group were consistently shorter. CONCLUSION: Plate fixation of displaced midshaft clavicle fractures with 4 cortices of purchase with 2 locking screws demonstrated no significant differences biomechanically when compared with fixation with 6 cortices of purchase and 3 nonlocking screws. Clinically, there were no significant differences in outcomes or complications seen in patients receiving 2- or 3-screw constructs. CLINICAL RELEVANCE: Clinical benefits of using the 3-screw construct for plate fixation include decreased surgical exposure, morbidity, and cost, and the use of shorter and noncontoured straight plates eliminates the extra time and technical difficulty associated with matching longer contoured plates to the complex morphology of the clavicle.

Reverse Anterior Cruciate Ligament Reconstruction Fixation: A Biomechanical Comparison Study of Tibial Cross-Pin and Femoral Interference Screw Fixation.

PURPOSE: To evaluate the biomechanical performance of tibial cross-pin (TCP) fixation relative to femoral cross-pin (FCP), femoral interference screw (FIS), and tibial interference screw (TIS) fixation. METHODS: We randomized 40 porcine specimens (20 tibias and 20 femurs) to TIS fixation (group 1, n = 10), FIS fixation (group 2, n = 10), TCP fixation (group 3, n = 10), or FCP fixation (group 4, n = 10) and performed biomechanical testing to compare ultimate load, stiffness, yield load, cyclic displacement, and load at 5-mm displacement. We performed cross-pin fixation of the looped end and interference screw fixation of the free ends of 9-mm-diameter bovine extensor digitorum communis tendon grafts. Graft fixation constructs were cyclically loaded and then loaded to failure in line with the tunnels. RESULTS: Regarding yield load, FIS was superior to TIS (704 ± 125 N vs 504 ± 118 N, P = .002), TCP was superior to TIS (1,449 ± 265 N vs 504 ± 118 N, P < .001), and TCP was superior to FCP (1,449 ± 265 N vs 792 ± 397 N, P < .001). Cyclic displacement for FCP was superior to TCP. Cyclic displacement for TIS versus FIS showed no statistically significant difference (2.5 ± 1.0 mm vs 2.2 ± 0.6 mm, P = .298). Interference screw fixation consistently failed by graft slippage, whereas TCP fixation failed by tibial bone failure. FCP fixation failed by either femoral bone failure or failure elsewhere in the testing apparatus. CONCLUSIONS: Regarding yield load, TCP fixation performed biomechanically superior to the clinically proven FCP at time zero. Because TIS fixation shows the lowest yield strength, it represents the weak link, and combined TCP-FIS fixation theoretically would be biomechanically superior relative to combined FCP-TIS fixation with regard to yield load. Cyclic displacement showed a small difference in favor of FCP over TCP fixation and no difference between TIS and FIS. CLINICAL RELEVANCE: Time-zero biomechanics of TCP fixation paired with FIS fixation show that this method of fixation can be considered a potential alternative to current practice and may pose clinical benefits in different clinical scenarios of anterior cruciate ligament reconstruction.

Transhumeral Portal for Arthroscopic Glenohumeral Resurfacing Procedures: A Cadaveric Study of the Safety and Accuracy.

PURPOSE: To evaluate the safety and accuracy of a transhumeral portal to arthroscopically access and prepare the glenohumeral articular surface without subscapularis transection or glenohumeral dislocation. METHODS: In 10 fresh-frozen cadaveric shoulders, we used a transhumeral portal and an anterior mini-open rotator interval exposure to arthroscopically prepare the humeral and glenoid articular surfaces. To evaluate our technique, we measured the distance from the portal to the branches of the axillary nerve and the biceps groove on the humeral extra-articular surface, the angle of trajectory of the portal through the humerus, and the accuracy of targeting the center-center of the humeral and glenoid surfaces. RESULTS: The transhumeral portal allows perpendicular access to the humeral and glenoid articular surfaces without damage to the subscapularis, supraspinatus, or axillary nerve. The transhumeral portal courses an average of 20.7 ± 15.0 mm from the closest terminal branch of the anterior branch of the axillary nerve, enters the humerus 8.8 ± 2.7 mm lateral to the biceps groove, and traverses the humerus at an angle of 46.0° ± 4.3° relative to the humeral intramedullary axis. Arthroscopic guidance resulted in an average distance of 8.1 ± 5.6 mm from the humeral center and 3.9 ± 1.0 mm from the glenoid center. CONCLUSIONS: Creating an arthroscopic transhumeral portal allows perpendicular access to the humeral and glenoid articular surfaces without injury to the axillary nerve, subscapularis transection, or dislocation of the glenohumeral joint. However, this transhumeral portal did traverse within 5 mm of a terminal branch of the anterior branch of the axillary nerve in 20% of our specimens. CLINICAL RELEVANCE: These findings describe an arthroscopic transhumeral portal that achieves perpendicular access to the glenohumeral joint surfaces without transection of the subscapularis or dislocation of the glenohumeral joint. This transhumeral portal may assist in articular cartilage repair and resurfacing of the glenohumeral joint.

Arthroscopic rotator cuff repair with biceps tendon augmentation.

Arthroscopic rotator cuff repair has become an increasingly popular treatment for rotator cuff tears. For orthopedic surgeons, treating large to massive rotator cuff tears is challenging in many ways. Patients with this pathology do not have the same healing rates and clinical outcomes as patients with smaller tears. Some surgeons have augmented repair with collagen-based grafts, but the success of this method has been limited. The same patient population may have concomitant biceps tendon pathology. Biceps tenotomy and biceps tenodesis are procedures in the surgeon's treatment armamentarium. Rotator cuff repair and biceps tenodesis or tenotomy are commonly performed simultaneously. In this article, we describe a technique that incorporates biceps tenodesis into double-row rotator cuff repair with the goal of providing more collagen and, ultimately, more healing potential.

Fixed-angle plate fixation in simulated fractures of the proximal humerus: a biomechanical study of a new device.

This study was performed to evaluate the biomechanical properties of a new device for displaced fractures of the proximal humerus. The device is a low-profile, fixed-angle plate specially designed for percutaneous application. With the use of embalmed cadaveric humeri, we simulated both noncomminuted and comminuted 2-part surgical neck fractures of the proximal humerus. Each humerus of a pair was then randomly fixed with either the new experimental device or the Association for the Study of Internal Fixation (ASIF) T-plate and mechanically tested to failure in an axial shear-loading model. The two fixation devices were evaluated in paired humeri with regard to mode of failure, stiffness, displacement at physiologic loads, and displacement, load, and energy at the point of ultimate load before failure. In the noncomminuted fracture trials the experimental device exhibited significantly greater stiffness (P <.001; P =.002 for normalized values) and ultimate load before failure (P =.015) and significantly less displacement at higher physiologic loads (P =.031). In the comminuted fracture trials the experimental device exhibited significantly greater stiffness (P =.048), ultimate load (P <.001) and energy absorbed (P =.048) before failure, and significantly less displacement at higher (P =.004) and lower physiologic loads (P =.011). The study demonstrates improved biomechanical properties for the new experimental device over the T-plate in simulated fractures of the proximal humerus. We extrapolate that these improved biomechanical properties may prove advantageous in future clinical investigation.

Anterior cruciate ligament injury in children: update of current treatment options.

As our society's interest in competitive athletics has grown, so has the participation of our youth. Unfortunately, along with this increase in participation has come a predictable increase in rate of injury. More specifically, anterior cruciate ligament injury in the skeletally immature individual is being recognized with increasing frequency and currently poses an unsolved clinical problem. Conservative management of midsubstance anterior cruciate ligament tears in the skeletally immature population has been shown to have an unfavorable prognosis related to functional knee instability, subsequent meniscal tears, and the development of early degenerative arthritis. Despite poor outcomes following conservative treatment, many orthopaedic surgeons have been reluctant to perform anterior cruciate ligament reconstructions in skeletally immature patients due to the potential for physeal injury and resultant growth disturbance. Although there is growing evidence in the literature suggesting that anterior cruciate ligament reconstruction in the adolescent population may be safely performed using anatomic, transphyseal techniques, there are insufficient data to provide concrete guidelines in treatment of anterior cruciate ligament injuries in the prepubescent population. Management of these injuries, therefore, must be based on the physiologic and skeletal maturity of the child. Anterior cruciate ligament reconstruction in the skeletally immature individual still poses a clinical problem with the safest and most effective techniques still evolving.