Physeal-sparing posteromedial portal approach reduced distance between guide pin and neurovascular structures.

PURPOSE: To compare a femoral physeal sparing anterior cruciate ligament (ACL) reconstruction technique utilizing a posteromedial portal to traditional transphyseal techniques with regards to anatomic tunnel positioning and proximity to important neurovascular structures. METHODS: Eight cadaveric knees were obtained for the study. Femoral tunnel guide pins were placed utilizing four different techniques: accessory anterior medial portal, posteromedial portal, trans-tibial, and figure-4 methods. The knees were then dissected and the following measurements taken: distance of each pin to the saphenous and peroneal nerve, popliteus tendon, neurovascular bundle, femoral ACL footprint and articular cartilage, and the angle of the guide pin entering the lateral femoral condyle. Fluoroscopic imaging was taken to determine the disruption of the physeal scar. RESULTS: Posteromedial portal guide pin was significantly closer to the neurovascular bundle, popliteal tendon and saphenous nerve when compared to the other 3 techniques, but was further from the peroneal nerve. It also had the smallest distance from the anatomic footprint of the ACL, and the largest angle to the lateral femoral condyle. The posteromedial portal guide pin had similar distance from the articular cartilage as the accessory anterior medial portal and figure-4 guide pin, with the trans-tibial guide pin being the farthest. The posteromedial portal guide pin failed to disrupt the physeal scar in all specimens, while the other three techniques consistently violated the physeal scar. CONCLUSION: The posteromedial portal technique offers an appropriate method for anatomic ACL reconstruction while protecting the distal femoral physis from injury. Care needs to be taken with this technique as it comes in closer proximity to some of the important neurovascular structures. This study indicates that posteromedial portal technique is a less technically challenging approach for physeal-sparing ACL repair with special attention required for the protection of neurovascular bundle from potential injury.

Device Design and Diagnostic Imaging of Radiopaque 3D Printed Tissue Engineering Scaffolds.

3D printed biomaterial implants are revolutionizing personalized medicine for tissue repair, especially in orthopedics. In this study, a radiopaque Bi 2 O 3 doped polycaprolactone ( PCL ) composite is developed and implemented to enable the use of diagnostic X-ray technologies, especially photon counting X-ray computed tomography ( PCCT ), for comprehensive in vivo device monitoring. PCL filament with homogeneous Bi 2 O 3 nanoparticle ( NP ) dispersion (0.8 to 11.7 wt%) are first fabricated. Tissue engineered scaffolds ( TES ) are then 3D printed with the composite filament, optimizing printing parameters for small feature size and severely overhung geometries. These composite TES are characterized via micro-computed tomography ( µ CT ), tensile testing, and a cytocompatibility study, with Bi 2 O 3 mass fractions as low as 2 wt% providing excellent radiographic distinguishability, improved tensile properties, and equivalent cytocompatibility of neat PCL. The excellent radiographic distinguishability is validated in situ by imaging 4 and 7 wt% TES in a mouse model with µCT, showing excellent agreement with in vitro measurements. Subsequently, CT image-derived swine menisci are 3D printed with composite filament and re-implanted in their corresponding swine legs ex vivo . Re-imaging the swine legs via clinical CT allows facile identification of device location and alignment. Finally, the emergent technology of PCCT unambiguously distinguishes implanted menisci in situ.

Surgical technique: when to arthroscopically repair the torn posterior cruciate ligament.

BACKGROUND: Posterior cruciate ligament injuries can occur as isolated ligament ruptures or in association with the multiligament-injured knee. Delayed reconstruction, at 2-3 weeks post-injury, is predominantly recommended for posterior cruciate ligament tears in the multiligament-injured knee. While acute bone and soft tissue avulsion patterns of injury can be amenable to repair, the described techniques have been associated with some difficulties attaching the avulsed ligament. DESCRIPTION OF TECHNIQUE: As part of a reconstruction/repair of a multiligament-injured knee, we performed arthroscopic primary repair of the posterior cruciate ligament by passing Bunnell-type stitches into the substance of the ligament using a reloadable suture passer. We then passed the sutures through drill holes into the femoral footprint of the ligament and tied them over a bony bridge. PATIENTS AND METHODS: We retrospectively reviewed three patients with posterior cruciate ligament tears associated with a multiligament-injured knee. All patients had posterior cruciate ligament soft tissue avulsions or "peel off" injuries diagnosed by MRI. The described repair technique was used to repair the posterior cruciate ligament avulsion. Minimum followup was 64 months (mean, 68 months; range, 64-75 months). ROM, stability testing, and functional outcome scores (Lysholm and modified Cincinnati) were recorded. RESULTS: Mean ROM was 0° to 127°. Posterior drawer testing was negative in all three patients. The mean Lysholm score was 92 and the mean modified Cincinnati score was 94. Followup MRI confirmed ligament healing in all patients. CONCLUSIONS: We believe arthroscopic posterior cruciate ligament repair for soft tissue peel off injuries is a technique that, when applied to carefully selected patients, may be helpful to the surgeon treating patients with a multiligament-injured knee. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Surgical Technique: Repair of Patella Tendon Rupture in a Previously Harvested Tendon for an Anterior Cruciate Ligament Reconstruction.

BACKGROUND: A rare cause of patellar tendon (PT) ruptures is complications after bone-PT-bone (BPTB) graft harvest for anterior cruciate ligament (ACL) reconstruction. The atypical tear pattern in these patients can be technically challenging to address. DESCRIPTION OF TECHNIQUE: A Krackow suture fixation of the medial, tibial based PT was fixed with a knotless suture anchor to the patella. A Krackow suture fixation of the lateral, patella based PT was fixed with a knotless suture anchor to the tibia. Fiber Tape was used for an Internal Brace. PATIENT AND METHODS: We retrospectively reviewed a single patient with a proximal-medial and distal-lateral PT rupture following BPTB graft harvest for an ACL reconstruction. The described repair technique was used to repair the PT rupture. Follow-up was 6-months. Range of motion (ROM), functional outcome scores, and patient-reported outcomes were assessed and recorded. RESULTS: Six-months postoperatively, the patient has regained full knee extension and flexion to 130 degrees. The patient has good quadriceps strength, and manual muscle testing shows no deficits in the operative leg. The patient is able to perform all of her activities of daily living and is discharged from physical therapy. CONCLUSION: We describe a novel technique that effectively repairs the atypical PT rupture pattern seen after ACL reconstruction using BPTB autograft. This technique allows for aggressive post-operative rehabilitation in ROM and strengthening. LEVEL OF EVIDENCE: Level V.

Biomechanical properties of tenotomy versus biceps knot in a cadaver model.

BACKGROUND: Biceps tenotomy and biceps tenodesis are the primary methods of treating biceps pathology. This study describes a new technique of tenotomy with the goal of autotenodesis to give the biceps a higher load to failure and decreased chance of a Popeye deformity. PURPOSE: The purpose of this study was to evaluate the strength of the "biceps knot", which is an outlet tenodesis of the biceps tendon and compare the biomechanical properties of this technique to tenotomy. METHODS: Ten matched cadaver shoulder pairs were used. In the tenotomy group, an arthroscopic tenotomy was performed at the labral biceps junction using a narrow angled biter. For the biceps knot group, a self-retrieving suture passing device was used to pass a suture as far lateral as possible. The suture was passed from just distal to the biceps insertion on the superior labrum and tied with a standard non-sliding arthroscopic knot. The humerus and biceps tendon were rigidly fixed to a materials testing machine and cyclically loaded at 10-20 N for 100 cycles at 1 Hz. After cyclic testing, a 2 N preload was placed on the tendon and the tendon was pulled in line with the bicipital groove until failure. RESULTS: The peak load to failure for the biceps knot was 58.9 N (SEM 8.2 N) and 37.3 N (SEM 4.6 N) for the tenotomy group (p = 0.046). The average stiffness for the biceps knot group was 4.2 N/mm (SEM 0.4 N/mm) and 3.2 N/mm (SEM 0.2 N/mm) for the tenotomy group (p = 0.031). CONCLUSION: Performing the biceps knot is a quick, easy and cost effective alternative to the current tenodesis options available.