Establishing Safe Extra-articular Parameters for Cortical Button Distal Fixation During Ulnar Collateral Ligament Reconstruction.

BACKGROUND: A variety of methods exist for fixation during ulnar collateral ligament (UCL) reconstruction on the ulna for the overhead throwing athlete. Current biomechanical evidence suggests that cortical button fixation may fail at a higher load and under more cycles than interference screw fixation alone, while also minimizing the risk of fracture. A safe angle for placement of this cortical button has not yet been determined. PURPOSE: To define a safe angle for cortical button deployment during UCL reconstruction to avoid violation of the proximal radioulnar joint (PRUJ). STUDY DESIGN: Descriptive laboratory study. METHODS: Measurements on 100 cadaveric ulna bones, 50 women and 50 men, were obtained referencing the entry point for ulnar fixation, which is 1 cm distal to the ulnar humeral joint line along the medial UCL ridge. Ulnar width at the entry point and distance to the PRUJ were obtained to calculate safe distal angulation, while distance from the entry point to the posterior ulnar crest ulnarly and distance from the PRUJ to the posterior ulnar crest radially were obtained to calculate safe posterior angulation. Ten bony measurements on the same group of specimens were performed by 3 authors to establish an interobserver reliability. Means, quartiles, and outliers were obtained for the calculated angles. Finally, recommended angles of entry were determined to be approximately 1 interquartile range above the upper limit. RESULTS: The mean distal angle of entry that was obtained was 11.32° (SD, ±4.80°; 95% CI, 10.37°-12.27°; P < .001). Three upper limit outliers were discovered: 24.20°, 23.4°, and 21.1°. The mean posterior angle of entry was 40.44° (SD, ±6.18°; 95% CI, 39.22°-41.67°; P < .001). There were no outliers for the posterior angle of entry. Interobserver reliabilities were strong for the 4 measurements. CONCLUSION: To be safely outside of the PRUJ utilizing a cortical button construct, we recommend 30° distal angulation and 60° posterior angulation for ulnar fixation during UCL reconstruction. Both parameters are 1 quartile above the highest calculated angle of entry. CLINICAL RELEVANCE: These data define safe parameters for distal fixation during UCL reconstruction and highlight a clear entry point for reference.

A Posterior Approach to Open Reduction and Internal Fixation of Displaced Posterior Cruciate Ligament Tibial Osseous Avulsions.

BACKGROUND: The true prevalence of displaced tibial-sided avulsion injuries of the posterior cruciate ligament (PCL; Video 1) is unknown, and the majority of data regarding management has been published in areas other than the Western world, such as China and India (perhaps due to the higher prevalence of two-wheeler motorcycle accidents in these areas). Despite the rarity of data, a better understanding of the approach, fixation techniques, and outcomes is necessary to provide quality patient care. These injuries generally require surgical intervention as nonoperative management leads to complications-specifically, knee arthrofibrosis1,2. There is no consensus regarding the optimal surgical approach for these injuries. A recent systematic review demonstrated that both open and arthroscopic surgical treatment provide satisfactory complication rates and outcomes in the majority of cases3. However, the arthroscopic approach can be performed by only a highly skilled arthroscopist; thus, in this article we focus on the open approach to reach a broader audience of capable surgeons. DESCRIPTION: The principal steps for open reduction and internal fixation of the tibial avulsion fracture include the following:Place the patient in a prone position and utilize a curvilinear L-shaped incision with the longitudinal portion over the medial head of the gastrocnemius muscle and the transverse portion starting distal to the joint line and extending laterally past the midline.Develop the interval between the semimembranosus and medial gastrocnemius muscles, as originally described by Burks and Schaffer4. Lateral retraction of the gastrocnemius muscle exposes the posterior aspect of the capsule, allowing for a vertical capsular incision to adequately visualize the avulsed osseous fragment.Prepare the osseous bed and remove hematoma and/or debris.Reduce the avulsed fragment and obtain provisional fixation with Kirschner wires.Confirm reduction under fluoroscopy with emphasis on sagittal plane alignment.Obtain definitive fixation with the method dictated by the fracture orientation. Options include screw(s) with or without a washer, sutures, Kirschner wires, staples, and toothed plates2,5-7. ALTERNATIVES: An arthroscopic approach can be performed, with results that are similar to those of an open procedure, but considerable expertise is required to perform this procedure arthroscopically. Nonsurgical management is not recommended as it frequently leads to loss of knee motion. RATIONALE: The exact operative indications for PCL injuries remain in question, but we believe that displaced tibial avulsion injuries at the PCL attachment always require operative treatment.