ABFAS Questions And Answers With Complete Solution Assured A+.

ABFAS Questions And Answers With Complete Solution Assured A+. Diastasis for Lisfranc = a fracture is present - 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 - fleck sign (1 and 2 met bases) first ray elevated arch flattens MCC direction lisfranc displaces - Dorsal and Lateral When to sx correct lisfranc - >2mm displaced wait 14 days if too much edema Approach to ORIF lisfranc fx - 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 - 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 - 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 - Base procedure aka proximal metaphyseal osteotomy. ABFAS Questions And Answers With Complete Solution Assured A+. -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 - Distal 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 - 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 - 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 - 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 - all do mcc for ex fix - 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 - rior tibial artery, artery of the tarsal canal dorsalis pedis artery, perforating peroneal artery. MCC of talar AVN - post-traumatic talar fracture Pain, swelling, with a history of previous injury or trauma. May have mechanical symptoms such as clicking, locking, or grinding. - AVN diagnose by a. Plain XR and MRI remain the most used and beneficial modalities. Classification of AVN - 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 - 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 - 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 - 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 - Posterior splint until sutures removed followed by NWB cast for 4 weeks. 1. 5-6 weeks PO, patient placed into a patellar tendon WB boot walker or brace but still kept strictly NWB (NWB ROM exercises started). 2. 8 weeks PO, XR are taken and the integrity of the talus is judged, PWB allowed on the PTB boot and as healing continues WB is progressed. Patient is then in rigid AFO for the first 6 months. types of Bone Grafts for Talar AVN - 1. Nonvascularized cancellous autograft can be taken from the iliac crest, calcaneus, or femoral head. Useful only in small, contained defects since this does not supply structural support. 2. Vascularized pedicle autograft: Rationale: limited area of necrotic bone can be debrided and removed and a vascularized graft is plugged in to bring in fresh, viable bone and perfusion. 3i. Bone allograft: 1. Nonvascular bulk allografts using fresh cadaver talus are a viable option for partial talar AVN. 2 Fresh talar bulk allograft i. Vascularized EDB pedicle graft surgical technique: - 1. Incision made 2 cm anterior to the tip of the lateral mal, curving toward the base of the 3rd MT. 2. Deep dissection carried down to lateral EDB muscle. An OT of the anterior calcaneal tubercle is performed, preserving the EDB muscle attachment. 3. Bore hole made into the lateral talar half of the talar neck extending into the talar body. Thorough curettage of the subchondral necrotic bone through the tunnel is performed. 4. Vascularized bone graft then contoured and snugly fit into the talar body without fixation. 5. PO Course: NWB cast 6-8 weeks with gentle ROM beginning at 6 weeks. Protected WB in fracture boot for another 4 weeks, then PT. Restriction of activity for the first year PO. Discuss Nonvascular bulk allografts using fresh cadaver talus for partial talar AVN. - a. Matched for side, gender, and approximate size and contain living cartilage. b. Rationale: fresh talar allografting may be selected over core decompression or EDB pedicle transfer when early collapse or overlying cartilage death has occurred and in cases in which clear margins of viable and necrotic bone are present. i. Allows large portion of diseased talus to be excised and replaced.