ABFAS Exam Questions with Correct Answers

ABFAS Exam Questions with Correct Answers Diastasis for Lisfranc = a fracture is present - Answer-2-5 mm of diastis betwen 1st and second mt base Chronic lisfrancs---ct=1 mm diastasis betwen 1st and 2nd mt or an increase of more than 15 degrees in the tarso-metatarsal joint signs of lisfranc on xray - Answer-fleck sign (1 and 2 met bases) first ray elevated arch flattens MCC direction lisfranc displaces - Answer-Dorsal and Lateral When to sx correct lisfranc - Answer-2mm displaced wait 14 days if too much edema Approach to ORIF lisfranc fx - Answer-middle cunii start proximal superior medical to the base of the 2nd mt possibly, 3rd mt. the first lag screw=KEY to REDUCTION. T if needed do a few more lag screws from the the bases metatarsals cuni. If cuni instability **screw across the nition=plates. Rules for bunions in the Juvenile pt - Answer-14-16 yrs. Ideal time frame to do sx for them is near skel. Maturity 11-15 yoa. Don't do anything joint destructive /don't remove the fib sesamoid. take mt adductus into consideration in a peds patient. Transpositional osteotomies ideal e.g. austin, kalish, offset V for rectus foottype and mod. IMA. But if they have Mt Adductus, really high IM or really high PASA Distal metaphyseal peds osteotomies - Answer-Austin, offset v, reverdin, mitchell, wilson and peabody. Mitchell and wilson SE including shortening, transfer lesions, elevatus, metatarsalgia How to fix bunion in a peds pt with IM 15 - Answer-Base procedure aka proximal metaphyseal osteotomy. -closed or open base wedge, cresentic procedure, lapidus =goal to make first and 2nd mt parallel without damaging the open physeal plate. base of proximal phalanx (aka proximal akin) of hallux what does it correct - AnswerDistal Angle DASA Fix pasa with mt head osteotomy like REVERDIN=lat cortex intact proximal cut parallel to 1st mt and distal cut parallel to articular surface Fix DASA W/ proximal akin disadvantage of the fusion vs plasty is the - Answer-fusion has less hallux propulsion and it can shorten which can then lead to contracture of the ehl or fhl You can walk it immediately vs plasty you cant cancellous vs cortical screws - Answer-Cannulated cancellous screws are used for metaphyseal fractures while cannulated and noncannulated cortical screws are used as lag screws for fixation of diaphyseal fractures. The main advantage of cannulated screws is that they can be inserted over a guide wire or guide pin. The diameter of the guide pin is much smaller than the cannulated screw Cannulated screws have a hollow central shaft. Both cortical and cancellous screws can be cannulated. 1st MPJ arthrodesis position - Answer-neutral rotation of the hallux, 10-15 degrees of valgus 20-30 degrees of dorsiflexion in reference to the axis of the first metatarsal Which does not affect bone healing: 1. Nutritional status, Rheumatoid or methotrexate patient, DM, tobacco hx, extent of initial injury, osteoporosis, other metabolic diseases, neuropathy - Answer-all do mcc for ex fix - Answer-1. m/c complications involve bone healing and not infection others: 1. delayed, nonunion, implant loosening, fracture, chronic pain, soft tissue inflammation, ulceration, or gross infection including osteomyelitis blood supply to talus - Arior tibial artery, artery of the tarsal canal dorsalis pedis artery, perforating peroneal artery. MCC of talar AVN - Answer-post-traumatic talar fracture Pain, swelling, with a history of previous injury or trauma. May have mechanical symptoms such as clicking, locking, or grinding. - Answer-AVN diagnose by a. Plain XR and MRI remain the most used and beneficial modalities. Classification of AVN - Answer-i. Hawkins type I fractures are non displaced vertical neck fractures. AVN is 10%. ii. Hawkins type II fractures consist of a vertical talar neck fracture with either subluxation or displacement of the STJ. AVN is 42%. iii. Hawkins type 3 fractures are characterized by a vertical talar neck fracture with subluxation or dislocation of both the ankle and STJs. AVN 91%. iv. Hawkins type IV fractures vertical talar neck fracture with subluxation or dislocation of the ankle, STJ, and the TNJ. AVN of 100%. what is Hawkins sign - Answer-AVN=Hawkins sign: subchondral radiolucent line along the superior aspect of the talar dome, which classically begins on the medial side of the talar dome, and appears 6-8 weeks after injury. indicative of talar revascularization; seen on AP or mortise view. MRI presentation of AVN - Answer-i. MRI is the most widely used modality to dx and potentially prevent further talar damage due to AVN. a. Normal T1 images will show a strong SI due to bone marrow elements in trabecular bone. b. In early AVN, diffuse marrow edema produces low signal intensity on T1 images and high SI on T2. c. In advanced stages, the diagnosis of AVN on MRI includes decreased SI on both T1 and T2 weighted images indicative of areas of devascularization or necrotic bone. Why perform arthroscopy for AVN - Answer-a. Arthroscopic Debridement and Core Decompression: i. Rationale: Thought to enhance revascularization and decrease intraosseous pressure. 1. Indicated in treatment of F&A stages I and II (partial AVN and those without collapse). ii. Technique: Standard AM and AL portals used for arthroscopy with a lateral sinus tarsi (lateral process) approach for retrograde drilling. post op avn sx - Answer-Posterior splint until sutures removed followed by NWB cast for