OHSUWhat Was That Pop? Acute

Andrea Herzka, MD Associate Professor Orthopaedic Surgery September 5, 2019 Disclosure OHSU• none Objective: Build confidence in managing the patient with acute knee • Integrate the history, physical exam and radiographs to sharpen a differential diagnosis • Build confidence in the nuances of the OHSUphysical exam: Recognize presentation Agenda

• Review Knee Anatomy • Creating a Differential • Clues in the History • Physical Exam Review OHSU• MRI findings • When to Refer to Orthopaedic Surgery Knee Anatomy OHSU ACL OHSU ACL Prevents Anterior Translation of the PCL OHSU PCL Prevents Posterior tibial translation MCL and FCL OHSU OHSU Types Of OHSU Articular Cartilage Problems OHSU

Focal Injury Diffuse Injury Articular Cartilage: / “Teflon Coat” OHSU Fibrocartilage = : “Shock Absorber”

Crescent shaped Medial = C-shaped LateralOHSU = Semicircular KNEE ANATOMY : Meniscus OHSU

 Deepens tibial surface  2o stabilizer Meniscus= Fibrocartilage: “Shock Absorber” OHSU Vasculature

“red-red“ “red-white“ zone zone

 Perimeniscal capillary plexus (med and lat genic) OHSUprovides blood supply to the periph. 1/3 of the meniscus

Photos by McGinty: Operative (1991) (from Arnoczky and Warren) Meniscus OHSU Longitudinal & Radial fibers Dissipate hoop stress Expand under compressive force Type I collagen Radial Split Tear: Poor Prognosis Root Avulsion: Difficult Longitudinal Tear: ? Zone OHSU MENISCUS: LOAD TRANSMISSION

• 50% load transmitted in full ext. • 85% joint load transmitted in 90º flex. • 15-34% (small) partial meniscectomy increases contact pressure to OHSUarticular cartilage dramatically “POP”: Differential Diagnosis

• Tear – ACL – MCL – PCL • • / Avulsion OHSU• Cartilage Flap Tear • Patellar/ Quad Tear • Ruptured Baker’s Cyst • Fracture Acute Injury

• Tried to cut or stop abruptly and felt a pop – ACL tear – Patellar Dislocation – Meniscus – Displaced Osteochondral Injury • Landed on my Anterior Shin/ Knee felt a pop OHSU– PCL – Fracture Acute Injury

• My knee was bent while wrestling and I felt a pop – Meniscus tear

• I felt a sharp pain in the back of my knee and my calf – Ruptured Baker’s Cyst

• Felt a pop and now even just the weight of a sheet at night on my inner knee causes severe pain OHSU– Inferiorly displaced medial meniscal fragment

• My kneecap popped out and I had to shove it back in Acute Xrays OHSU OHSU OHSU Physical Exam

EFFUSION: trace, small, moderate, large, tense SKIN:

WEIGHTBEARING RIGHT: Alignment LEFT: Alignment OHSU(varus= bowlegged; valgus= knock-kneed) FEET: Arch height (pronation vs supination) : Pain generated? Where? GAIT: Antalgic, flexed knee ACTIVE ROM: Right: ***, Left: *** PATELLA: RIGHT LEFT NORMAL TILT Neutral Neutral GLIDE 2 quadrants 2 quadrants CREPITATION None None J SIGN Absent Absent TENDERNESS None None APPREHENSION Neg Neg

LIGAMENTS: RIGHT LEFT

VALGUS AT 30° Neg Neg VARUS AT 30° Neg Neg LACHMANOHSU0 0 ANT. DRAWER Firm endpoint, Firm endpoint, symmetric symmetric PIVOT SHIFT Absent Absent POST. DRAWER Negative Negative PRONE DIAL 30° Symmetric Symmetric PRONE DIAL 90° Symmetric Symmetric PERIARTICULAR TENDERNESS:

RIGHT LEFT JLT MEDIAL Neg Neg JLT LATERAL Neg Neg MCMURRAY Neg Neg WILSON Neg Neg PAT TENDON Neg Neg OHSUNVS: Intact Ober Sign: ? Tight IT band Inspection

• Effusion • Alignment • Gait (if able) – Antalgic OHSU– Flexed knee –?DDX Patella

• Apprehension • Glide/ translation OHSU• Tilt Patellar Translation/ Apprehension OHSU Patellar Dislocation: Initial Treatment

• Aspirate Hemarthrosis – (look for fat droplets) • Use small rolled kerlix to make a lateral OHSUpatellar bumper and ace wrap for Patellar Dislocation: Treatment

• Conservative if traumatic etiology normal anatomy and no osteochondral injury – PT – Short term bracing

• Surgical options OHSU– Soft tissue procedure • MPFL – Bony procedure • Tibial Tuberosity Osteotomy OHSU OHSU ACL tear

• LACHMAN • ANT. DRAWER OHSU• PIVOT SHIFT ACL Presentation

• Pop- then knee felt wobbly • Gradual swelling • Flexed knee gait • Full extension very OHSUuncomfortable- feels like deep pinch • Guards against lachman Management of Acute ACL Tear

• Order MRI • Referral to ortho • Can aspirate knee if large hemarthrosis • Knee immobilizer or hinged knee brace if poor quad function but encourage ROM OHSU• If MRI shows no displaced meniscus tear OK to WBAT and start ACL “prehab” PT Definitive Treatment of ACL Tear

• Surgery prevents recurrent giving way and meniscus tears, allows more rigorous and cutting • Surgery does not prevent and does not change the timeline of post OHSUtraumatic OA • There is a small cohort of patients who can do well with conservative treatment Meniscus pathology

• Jointline tenderness • McMurray OHSU• Appley Meniscus Tears

• Nondisplaced oblique or horizontal tears can usually be treated conservatively • Displaced Bucket Handle requires urgent referral and usually surgical intervention OHSU• Peripheral longitudinal- ? Repair • Root Avulsion- ? Repair – Prognosis deeply affected (extrusion) Peripheral Longitudinal Tear OHSU Meniscal Root Injuries OHSU Radial Split Tear: The Kiss of Death OHSU I Know What Caused That Pop

• Thank You! • Andrea Herzka, MD • [email protected] OHSU• (503)494-4000