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Background: Radiological risk factors for an osteochondral fracture (OCF) associated with patellar instability are rarely studied, particularly in patients with recurrent instability., Purpose: To identify specific radiological characteristics that relate to the increased prevalence of OCFs associated with patellar instability., Study Design: Case-control study; Level of evidence, 3., Methods: Patient data (n = 730) from the Justifying Patellar Instability Treatment by Early Results (JUPITER) multicenter study were reviewed for radiological findings. Trochlear crossing sign, Caton-Deschamps index (CDI), tibial tubercle-trochlear groove (TT-TG) distance, patellar tilt, trochlear depth, trochlear bump, sulcus angle, and patellar subluxation were measured on radiography or magnetic resonance imaging and classified into 2 categories based on pathological thresholds for general patellar instability. Patients were grouped according to the presence or absence of an OCF and analyzed with the Mann-Whitney test, chi-square test, and multivariate regression., Results: A high CDI was associated with a 0.43 decreased odds of an OCF, while a high TT-TG distance was a risk factor for an OCF, with a 2.17 times increased odds. Although a first-time dislocation increased the odds of an OCF by 4.72 times, recurrent instability was found to have the same predictive relationship of CDI and TT-TG distance with fracture incidence. A lower CDI, a shallower trochlear depth, a smaller trochlear bump, and the presence of a patellar subluxation were more common in patients with OCFs. A lower CDI, positive trochlear crossing sign, and shallower trochlear depth were more common in the subset of patients with recurrent instability and associated OCFs., Conclusion: Patella alta was protective of OCFs in patients with first-time and recurrent instability, while a lateralized tibial tubercle was a risk factor. These radiological characteristics should guide health care professionals on the risk of future OCFs during treatment planning after a patellar instability event., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: H.B.E. has received support for education from Pylant Medical, speaking fees from OrthoPediatrics, and hospitality payments from Stryker. P.L.W. has received royalties from Elsevier and support for education from Pylant Medical, AlloSource, Vericel, Ossur, and Arthrex. D.E.K. has received consulting fees from DePuy Synthes and Miach Orthopaedics and support for education from Kairos Surgical. S.N.P. has received consulting fees from Pfizer and Arthrex; support for education from CDC Medical, Arthrex, and Gotham Surgical; and hospitality payments from Linvatec. B.E.S.S. has received consulting fees from Arthrex and support for education from Gotham Surgical. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Muscle injuries are the most common injuries in sports, with hamstring injuries accounting for 29% of all injuries in athletes. These injuries lead to prolonged impairment and have a reinjury risk of 12% to 31%. They range from mild muscle damage without loss of structural integrity to complete muscle tearing with fiber disruption. Novel MRI scores are increasingly being used and allow a more precise prediction of return to sport. In this article, the authors review the history, mechanisms of injury, and classification systems for hamstring injuries as well as present the latest evidence related to the management of hamstring injuries, including intramuscular and both proximal and distal insertional injuries. Indications for surgical treatment of certain proximal and distal avulsions, biological augmentation to the nonoperative treatment of midsubstance injuries, and advances in risk reduction and injury prevention are discussed.