AOBOS Orthopedics common mistakes
AOBOS Orthopedics · Understand the traps and how to avoid them.
Names an OMT technique (HVLA, muscle energy, counterstrain) for the patient in the vignette without first stating the screening examination and the contraindications that were considered.
Osteopathic content gets studied as a memorized list of techniques, so candidates reach for a technique name to show familiarity and skip the safety screen the item is actually testing.
What to do instead
Before naming a technique, verbalize the screen in order: acute fracture or dislocation, cord/cauda equina signs, segmental instability, anticoagulation or bleeding risk, local infection, and positioning tolerance. Then justify the technique chosen against those findings, and name the alternative you would use if the screen were positive.
Describes the fixation construct for an open tibial shaft fracture without stating antibiotic timing, tetanus status, and the urgency of irrigation and debridement.
The hardware choice is the most visually memorable part of the case, so under time pressure the sequence that actually determines infection risk gets treated as background trivia.
What to do instead
Answer every open-fracture prompt in a fixed sequence: ATLS primary survey and neurovascular documentation, IV antibiotics within one hour plus tetanus prophylaxis, debridement timing, provisional stability, soft-tissue coverage plan, then definitive fixation. Rehearse the sequence until it comes out before the implant name.
Splints a reduced knee dislocation and arranges clinic follow-up without documenting pre- and post-reduction vascular examination, ankle-brachial index, or the plan for CT angiography.
The post-reduction radiograph looks satisfactory, so the case reads as solved and the arterial injury that defines the diagnosis is never addressed.
What to do instead
Treat every knee dislocation as a vascular injury until proven otherwise: state the ABI before and after reduction, the threshold that triggers CT angiography, the plan for serial examinations or admission, and the findings that would send the patient to the operating room for exploration.
Recommends a two-stage exchange for a painful total knee without first stating the serology, joint aspiration results, and culture data used to establish infection, or without saying what would make the diagnosis aseptic loosening instead.
Two-stage exchange is a high-salience phrase, so it is offered whenever the stem mentions a painful arthroplasty, bypassing the diagnostic reasoning the question is built on.
What to do instead
Work the case in order: ESR and CRP, aspiration with synovial fluid cell count and differential plus cultures, explicit criteria (ICM or MSIS), organism and host status, then the surgical strategy. Close by stating the alternative diagnosis and the findings that would move you to single-stage or aseptic revision.
Selects an arthroscopic Bankart repair for recurrent anterior shoulder instability without estimating glenoid bone loss or addressing an engaging Hill-Sachs lesion.
The Bankart lesion is the first thing learned about instability, and quantifying bone loss requires pulling imaging and track concepts forward under time pressure, so it gets skipped.
What to do instead
Before committing to soft-tissue repair, state the bone-loss estimate from imaging or the glenoid track concept, the associated failure risk, and the bony procedure (coracoid transfer or similar) indicated when loss is substantial. Name why an isolated labral repair fails in that setting.
Answers a lumbar stenosis vignette with a single verb such as "decompress" or "fuse" without stating the alignment, listhesis, or dynamic instability findings and the red-flag workup that drove the decision.
Surgical decision-making gets compressed into one word, and candidates assume the examiner already accepts the indication rather than requiring the findings that justify it.
What to do instead
Lead with the findings: grade of listhesis and dynamic motion on flexion-extension, sagittal alignment, neurogenic claudication versus vascular claudication, and any red flags such as fever, cancer history, or bowel and bladder change. Then name the procedure and the levels, and say what would change your plan.
Labels a snuffbox-tender wrist with negative radiographs as a sprain and advises repeat films at follow-up only, without immobilization or return precautions.
The radiograph is read as normal and the examination is otherwise unimpressive, so the occult-fracture pathway never gets triggered.
What to do instead
State the diagnosis as a presumed occult scaphoid fracture: thumb spica immobilization, repeat imaging or MRI in seven to fourteen days, and explicit return precautions. Add why missing it matters: proximal pole avascular necrosis and nonunion risk, which are the points the item is scoring.
Plans open reduction and internal fixation of a Weber B ankle fracture without stating how the syndesmosis will be assessed and how it will be fixed if found unstable.
The fibular fracture dominates the answer, and syndesmotic evaluation is an intraoperative decision step that candidates have rarely rehearsed out loud.
What to do instead
Build the syndesmosis into the plan explicitly: gravity or external rotation stress views preoperatively, then intraoperative Cotton and external rotation tests after fibular fixation, the chosen fixation (screw versus suture button), and the resulting weight-bearing and rehabilitation implications.
Interprets a pediatric elbow radiograph using adult ossification assumptions, calling a lateral condyle fracture normal or filing it under a nondisplaced supracondylar pattern.
The sequence and rough ages of ossification centers are not automatic recall, and the lateral condyle fracture can appear as a small metaphyseal flake rather than an obvious displaced fragment.
What to do instead
Recite the ossification sequence and approximate ages before interpreting, obtain contralateral comparison views, and treat any lateral metaphyseal fragment as a lateral condyle fracture. State that it crosses the physis into the joint, requires anatomic reduction with fixation when displaced, and carries a real nonunion risk if under-treated.
Recommends excisional biopsy of a deep soft-tissue mass before cross-sectional imaging and staging, or without planning a biopsy tract that can be removed en bloc with the tumor.
The word "biopsy" cues the most familiar procedure, and candidates underestimate how an unplanned excision or misplaced tract contaminates compartments and compromises limb salvage.
What to do instead
Sequence it: contrast-enhanced MRI and staging studies first, then biopsy at the treating center along a longitudinal tract that can be excised with the specimen. State explicitly that an unplanned excision changes the definitive surgery and may cost the limb.