Stress radiographs under anesthesia for painful chronic lateral ankle instability Department of Orthopedic Surgery, Inje University Ilsan Paik Hospital, Goyang-si, Gyeonggi-do, South Korea *W Institute for foot and ankle disease and trauma, W Hospital, Daegu, South Korea *Jun Young Choi, Jin Soo Suh
Stress radiographs under anesthesia for painful chronic lateral ankle instability Jun Young Choi, Jin Soo Suh My disclosure is in the Final AOFAS Mobile App. I have no potential conflicts with this presentation.
Stress radiographs for lateral ankle instability Anterior drawer test With plantar flexion 10 o - Absolute value of over 10mm - 5mm greater than contralateral Varus stress test - Absolute value of over 9 o - 3 o greater than contralateral - Absolute value of over 15 o Louwerens JWK et al. Foot Ankle Int. 1995 Coughlin MJ et al. Surgery of foot and ankle
Muscle guarding Following injury, the muscle that surrounds the injured area contract, in effect, splint that area, thus minimizing pain by limiting movement. Muscle guarding in chronic medial elbow instability Instability may be difficult to elicit in an awake patient on examination due to muscle guarding Purpose of this study Lannotti JP et al. The Netter collection of Medical Illustrations To evaluate the accuracy and efficacy of stress radiographs at outpatient clinic for painful chronic lateral ankle instability Hypothesis Muscle guarding would interfere the accurate stress radiographs performed at outpatient clinic
Materials & Method From Jan, 2014 ~ Jun, 2016 Patients underwent Modified Broström operation for painful chronic lateral ankle instability (pain/instability duration > 3 months from initial injury) Exclusion criteria (1) Bilateral injury (2) General laxity Manual anterior / varus stress radiographs 1. Pre-operative at outpatient clinic & 2. Intra-operative under spinal anesthesia The mean of the results of two, trained, blinded radiographic technicians
Materials & Method 96 cases in 96 patients - Mean age : 29.63±12.04 (15~76); Right 59, Left 37; Male 65, Female 31 Concomitant operation - Ankle arthroscope : 42 (1) Anterior impingement sx. 41 (2) OLT 21 (medial 15, lateral 6) - Os subfibulare excision 20 - Supramalleolar osteotomy 1 - Tarsal tunnel release 1 MRI grade of ATFL injury Complete tear (n=39) Partial tear (n=46) Instability without rupture (n=11) Lee KM et al. Skeletal Radiol. 2013
Results (Anterior drawer test) [Affected limb] [Changes via anesthesia] At clinic Under anesthesia Overall (96) 6.08 mm 8.64 mm Complete (39) 6.13 mm 8.80 mm Partial (46) 6.15 mm 8.60 mm Without rupture (11) 5.62 mm 8.30 mm Overall (96) Complete (39) Partial (46) Without rupture (11) Affected limb 2.57 mm 2.68 mm 2.45 mm 2.68 mm Contralateral limb 0.09 mm 0.003 mm 0.16 mm 0.09 mm [Affected limb Contralateral limb] Overall (96) Complete (39) Partial (46) Without rupture (11) At Clinic 0.37 mm 0.3 mm 0.46 mm 0.24 mm Under Anesthesia 2.84 mm 2.97 mm 2.75 mm 2.83 mm
Results (Varus stress test) [Affected limb] At clinic Under anesthesia [Changes via anesthesia] Overall (96) 10.40 o 12.40 o Complete (39) 12.56 o 14.60 o Partial (46) 8.98 o 11.07 o Without rupture (11) 8.48 o 9.99 o Overall (96) Complete (39) Partial (46) Without rupture (11) Affected limb 2.01 o 2.04 o 2.09 o 1.51 o Contralateral limb 0.68 o 0.89 o 0.58 o 0.28 o [Affected limb Contralateral limb] Overall (96) Complete (39) Partial (46) Without rupture (11) At Clinic 3.51 o 4.7 o 2.59 o 3.00 o Under Anesthesia 4.83 o 5.84 o 4.11 o 4.23 o
Discussion Lee KM et al (Skeletal Radiol, 2013) ATFL injury and PTFL injury on MRI significantly affected tibiotalar tilt angle and anterior drawer on stress radiographs Becker HP et al (Foot Ankle, 1993) Need for anesthesia to obtain more reliable results from stress diagnostic tests in the acutely sprained ankle Anterior drawer / Varus stress radiographs under anesthesia - Absolute value : significantly increased after anesthesia - In terms of differences between contralateral limb, significantly increased after anesthesia - No significant differences among MRI grades
Discussion Anterior drawer / Varus stress radiographs under anesthesia - Relatively small value even for complete tear Often not matched to the diagnostic value Limitations of our study 1) Stress test was performed manually 2) Not correlated to concomitant CFL injury 3) Small subject number (96) Summary Anterior drawer / varus stress test performed at outpatient clinic may not be accurate for the patients with painful chronic lateral ankle instability
M/20 Chronic painful Lt. ankle instability for 3 years At clinic Varus stress test 9 o At clinic Anterior drawer test 6.9mm Under anesthesia 9.4mm (increased by 2.5mm) Under anesthesia 13 o (increased by 4 o )
References 1. Johansen A. Radiological diagnosis of lateral ligament lesion of the ankle: a comparison between talar tilt and anterior drawer sign. Acta Orthop Scand. 1978;49:295-301. 2. Coughlin MJ, Mann RA. Athletic injuries to the soft tissues of the foot and ankle. In: Coughlin MJ, Mann RA, Saltzmann CL. Surgery of the foot and ankle, 9 th ed. Philadelphia: Mosby; 2014. p.1561-4. 3. Lee KM, Chung CY, Kwon SS, Chung MK, Won SH, Lee SY, et al. Relationship between stress ankle radiographs and injured ligaments on MRI. Skeletal Radiol. 2013;42:1537-42. 4. Becker HP, Komischke A, Danz B, Bensel R, Claes L. Stress diagnostics of the sprained ankle: evaluation of the anterior drawer test with and without anesthesia. Knee Surg Sports Traumatol Arthrosc. 1993;14:459-64. 5. Frost SC, Amendola A. Is stress radiography necessary in the diagnosis of acute or chronic ankle instability? Clin J Sport Med. 1999;9:40-5.