LIMB LENGTH 2024(1).pptx

LIMB LENGTH DISCREPANCIES Clinical Podiatric Biomechanics & Surgery 4/16/24 KEVIN SMITH, DPM FACFAS CPMS Mission Statement To educate a diverse group of highly competent and compassionate podiatric health professionals to improve lives in a global community. Lecture Objectives  Identify the etiolog...

LIMB LENGTH DISCREPANCIES Clinical Podiatric Biomechanics & Surgery 4/16/24 KEVIN SMITH, DPM FACFAS CPMS Mission Statement To educate a diverse group of highly competent and compassionate podiatric health professionals to improve lives in a global community. Lecture Objectives  Identify the etiologies, clinical examination, compensation and conservative treatment of limb length discrepancy. LIMB LENGTH DISCREPANCY     Very Common 65-75% of the population What is a Significant LLD? 3mm - 22mm TYPES OF LLD    Structural LLD - Anatomical shortening Functional LLD - Due to biomechanics Combination ETIOLOGY OF LLD  STRUCTURAL – Polio – Physeal Damage – Congenital Dysplasia – Post Surgical STRUCTURAL LLD COMPENSATION  Pelvis tilts downward on short side  Scoliosis with convex side over short limb – Reducible with NWB - can become rigid ETIOLOGY OF LLD  FUNCTIONAL – Excessive STJ pronation » Greater than 3º of eversion when compared to contralateral limb – Joint contracture – Axial malalignment » Spinal - frontal or transverse plane deformity » Pelvic - triplane deformity – Induced by shoegear SYMPTOMS ASSOCIATED WITH LLD    Asymptomatic Pain with standing and WB Sacroiliac joint pain due to pelvic tilt – Pelvic Tilt Syndrome  Knee pain – Lateral on short limb – Medial on long limb  Low back pain – Due to disc protrusion with scoliosis SYMPTOMS ASSOCIATED WITH LLD  Foot pathology – Long limb will pronate to shorten – Short limb will supinate to lengthen  Pronation is a compensation for structural LLD or a cause of a functional LLD CLINICAL EXAMINATION  Direct clinical measurement – ASIS to medial malleolus » Inaccurate » Obese patients » Joint contracture not accounted for » Torsion of bones not accounted for » Pelvic torsion not accounted for  Variations – ASIS to lateral malleolus – Umbilicus to medial malleolus CLINICAL EXAMINATION  Indirect clinical measurement – WB with foot in resting calcaneal stance position – Pelvic landmarks palpated, keeping hands parallel – ASIS and PSIS located – Blocks of a known thickness placed under short side until landmarks are at same level CLINICAL EXAMINATION   Pelvic height difference not accounted for Third reference point added for accuracy – Greater Trochanter - If this measurement is equal then the LLD occurs within pelvis RADIOGRAPHIC EVALUATION  Radiographic films taken of long bones and measured for structural LLD COMPENSATION OF LLD   Body attempts to correct LLD Pelvic Rotation – Posterior pelvic rotation with pronation on long limb – Anterior pelvic rotation with supination on short limb  Functional scoliosis - most common compensation SCOLIOSIS   Must determine if scoliosis is functional and a result of a LLD or if is the primary pathology and the LLD is a compensation for the scoliosis Fixed scoliosis does not reduce with NWB TREATMENT   No absolute value or LLD that requires treatment Treatment is based on the following criteria – Symptomatic patient – Patient predisposed to injury – Decreased tolerance to activity – Presence of scoliosis – Shoulder or pelvic tilt – Knee pain – Altered gait TREATMENT     Must address etiology If functional caused by increased pronation, must correct with orthosis If structural then a lift is used If combined, then an orthotic with a lift LIFTS     If discrepancy 1 cm or more, a full length lift is used to prevent equinus Increase in increments of 3mm (1/8”) per week Can get 8 mm of lift in a normal shoe If greater than 8 mm needed, apply 50% of lift to shoe of short side and acquire other 50% by deepening shoe on long side EBM  We evaluated the gait of thirty-five neurologically normal children who had a limb-length discrepancy of the lower extremities that ranged from 0.8 to 15.8 per cent of the length of the long extremity (0.6 to 11.1 centimeters). The twenty-two boys and thirteen girls had an average age of thirteen years (range, eight to seventeen years). No patient had a substantial angular or rotational deformity of the lower extremities. We found no correlation between the actual discrepancy or the per cent discrepancy and any of the dependent kinematic or kinetic variables, including pelvic obliquity. Discrepancies of less than 3 per cent of the length of the long extremity were not associated with compensatory strategies. When a discrepancy was 5.5 per cent or more, more mechanical work was performed by the long extremity and there was a greater vertical displacement of the center of body mass. Clinically, this degree of discrepancy was manifested by the use of toe-walking as a compensatory strategy. Children who had less of a discrepancy were able to use a combination of compensatory strategies to normalize the mechanical work performed by the lower extremities. EBM  Prospective level 3 study  http://jbjs.org/content/79/11/1690 THANK YOU