The extensor mechanism of the knee-consisting of the four muscles of the quadriceps, the quadriceps tendon, the patella, and the patellar ligament-is essential for lower extremity function during both standing and ambulation. The presence of articular cartilage and growing physes in the pediatric knee, coupled with the generation of significant tensile force, creates an opportunity for pathology unique to the pediatric population.Tibial tubercle fractures and patella injuries are quite rare, and even pediatric-trained orthopaedic surgeons may not be exposed to these injuries on a regular basis. It is the intent of this article to discuss the current literature regarding the mechanism of injury, diagnostic workup, classification, indications for surgical versus non-surgical management, and techniques for operative management for both tibial tubercle and patella (transverse and sleeve) fractures.

Background: Rotator cuff tears are common injuries that are reliably treated with arthroscopic repair, producing good to excellent results. The Western Ontario Rotator Cuff (WORC) index is a validated disease-specific instrument used to assess patient outcomes; however, no study to date has correlated WORC index with treatment failure. Purpose: To evaluate the WORC index as a predictor for successful treatment in arthroscopic rotator cuff repair. An additional purpose was to identify patient and tear characteristics associated with risk of treatment failure. Study Design: Case-control study; Level of evidence, 3. Methods: This study reviewed a total of 500 patients who underwent arthroscopic rotator cuff repair with a minimum of 2-year follow-up. Patient charts were reviewed for treatment failures, defined as persistent or recurrent shoulder pain or weakness, leading to further workup and identification of a failure to heal or recurrent tear by magnetic resonance imaging. Patient demographic and comorbidity data were gathered and correlated with risk of failure. All patients completed WORC questionnaires, and scores were correlated with risk of treatment failure. Results: There were 28 (5.6%) treatment failures at a median 28 weeks (SD, 42 weeks) postoperatively. Patients claiming workers’ compensation were 3.21 times more likely (odds ratio; P = .018) to fail treatment. Posterior interval tears (those including infraspinatus) were 3.14 times more likely ( P = .01) to fail than anterior interval tears. Tear size was associated with treatment failure; the odds of failure was 3.24 for a 2-tendon tear and 5.83 for a 3-tendon tear ( P = .03). Tears involving the nondominant arm were associated with an increased risk of failure by a factor of 3.04 (95% CI, 1.01-9.11; P = .047). A WORC score ≥80 was associated with a 95% probability of treatment success at 1 year. Conclusion: After arthroscopic rotator cuff repair, patients with WORC scores ≥80 at 1 year have a 95% probability of successful treatment and likely do not benefit from continued follow-up visits. Furthermore, several risk factors were identified that may influence outcomes after rotator cuff repair, including workers’ compensation, location of tear, tear size, and hand dominance.

Posterior malleolar fractures (PMFs) have been demonstrated to result in poorer outcomes than other types of ankle fractures with a higher incidence of posttraumatic arthritis. Accordingly, there has been a recent surge in interest in reduction and fixation of PMFs. Operative criteria for PMFs have been based on size, step-off, ankle joint instability, and syndesmotic injury, though universally accepted criteria have yet to be defined. Anatomically, the posterior malleolus is important as an insertion point of the posterior inferior tibiofibular ligament and thereby may play a role in syndesmotic stability. However, the important lateral ankle ligament complex is also important in governing stability of the talus within the ankle mortise. PMFs have been classified by the Haraguchi system based on morphology and extent. Radiographs, although always appropriate to perform as the initial diagnostic imaging study, are likely insufficient to evaluate the size and displacement; computed tomography scan is recommended for optimal evaluation for preoperative planning. When treating the posterior malleolus by a posterolateral approach, prone and lateral positioning of the patient facilitates exposure, although it can also be performed in the supine position with a large bump and with a leg that can be safely passively internally rotated sufficiently, or externally rotated if a posteromedial approach is used. Fixation can be performed with lag screw fixation alone versus buttress or standard plating techniques. Wound complications and posttraumatic arthritis are relatively common complications encountered in the treatment of PMFs. Level of Evidence: Diagnostic Level V. See Instructions for Authors for a complete description of levels of evidence.

Background: DNA structure checkpoints are conserved eukaryotic signal transduction pathways that help preserve genomic integrity. Upon detecting checkpoint signals such as stalled replication forks or double-stranded DNA breaks, these pathways coordinate appropriate stress responses. Members of the PI-3 kinase related kinase (PIKK) family are essential elements of DNA structure checkpoints. In fission yeast, the Rad3 PIKK and its regulatory subunit Rad26 coordinate the detection of checkpoint signals with pathway outputs.