Recurrent Traumatic Patellar Dislocation: Case Example and Tying it all Together?? Christopher M. Larson MD

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1 Recurrent Traumatic Patellar Dislocation: Case Example and Tying it all Together?? Christopher M. Larson MD

2 Disclosures Consultant: Smith & Nephew A3 surgical Stockholder: A3 surgical

3 Case Presentation: History 37 y/o male with history of traumatic Left patella dislocation 5 years prior (fine since) 3 weeks ago jumped out of a car to dance to MC Hammer s You Cant Touch This and dislocated his patella again / self reduced (? BEER involved) Walking with an Immobilizer as he s had several more subluxation episodes since

4 Physical Examination Moderate Effusion TTP medial side of the knee + Lateral Patellar Apprehension 3 quadrants lateral translation 1.5 quadrants medial Patella everts past horizontal 0-45 degrees ROM Other Ligaments stable

5 What I look for on Radiographs / MRI??

6 Plain Radiographic Measures

7 Plain Radiographic Measures

8 MPFL Injury Possible MRI Findings Patella Attachment, Intrasubstance, Femoral Attachment Osseous Contusions Lateral Femoral Condyle Medial Patellar Facet Chondral / Osteochondral injury Medial Patellar Facet Loose body

9 Typical MRI Measurements Insall Salvati ratio = < 1.2 Caton Deschamps = < 1.2 TTTG = < 15-20mm TTPCL = < 24mm Patella / Trochlea Overlap / Index (PTI) = > 30% Sulcus Angle= < 145 deg

10 Current Case: Imaging Findings and Measurements

11 Case Example: Plain Radiographs Insall Salvati = 1.06 Caton Deschamps = Crossing Sign Double Contour Sign Sulcus Angle = No Sunrise / Merchant / Loren view Check MRI!!

12 Case Example: MRI Findings Significant MPFL injury = Intrasubstance and Femoral Sided Contusion Lateral Femoral Condyle No Osteochondral Loose Body

13 Case Example: MRI Measurements TTTG = 13mm TTPCL = 21mm Patellar / Trochlear Overlap / PTI = 40% Sulcus Angle = 145 deg Borderline Abnl

14 Final Diagnosis / Pathoanatomy Recurrent (2 nd ) Traumatic Patellar Dislocation MPFL femoral sided and intrasubstance injury No Osteochondral Loose body Mild to Moderate Trochlear Dysplasia Normal Patellar Height & Trochlear Overlap, and normal TTTG / TTPCL

15 Surgical Plan Knee Arthroscopy to evaluate for PF chondral injury, occult loose body, and other structures MPFL reconstruction with ST autograft to address the essential lesion No distal realignment with fairly normal patellar height and tibial tubercle anatomy No Trochleoplasty with traumatic dislocations X 2 and relatively mild trochlear dysplasia

16 Prior to Surgery Sent to Physical Therapy for Swelling control and restoration of ROM Continued to use Immobilizer when up and around but encourage him to come out frequently for ROM 3 weeks later struggling with apprehension out of brace but motion slowing improving 6 weeks post-injury brought to the OR and EUA = 0-90 degree ROM and with gentle MUA improved to 130

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19 Post-operative Radiograph

20 Post-operative Course WBAT with brace locked in extension 0 45 degrees for 2 weeks then up to 90 degrees to 6 weeks post-op and then as tolerated. Slow to progress with ROM so PT asked to be more aggressive with ROM and I agreed ROM as tolerated. 5 weeks = 0-60 degrees ROM 6 weeks post-op planned Scope / MUA

21 Recommended MUA and Arthroscopic Lysis of Adhesions Improved from 3 60 degrees to degrees intra-operatively

22 Post-Manipulation CPM and Extension Dynasplint 3 days post-op 0-93 degrees 3 weeks full revolution on a stationary bike 6 weeks = ROM McConnell taping for pain management

23 Most Recent 5.5 month F/U 1.5 quadrants lateral patellar translation No lateral patellar apprehension degrees ROM No extensor lag

24 No pain with Jogging Most Recent 5.5 month F/U Knee Outcomes Survey = Initial = 14.3 Most Recent = 92.9 Irrgang JJ, Snyder- Mackler L, Wainner RS, Fu FH, Harner CD, JBJS 1998

25 Conclusions Surgery for Primary dislocation = Osteochondral loose body, Boney Avulsion of MPFL / Patella,?? High Risk Anatomy?? Recurrence rate after Primary Dislocation = 15-49% 55% unable to return to prior level of Sports Recurrence rate after subsequent Dislocation = 50% BE THOUGHTFUL = Very complicated pathoanatomy / risk factors and a variety of surgical procedures are described to manage these risk factors Genu Valgum, Trochlear Dysplasia, Patella Alta, Increased TTTG / TTPCL, Femoral Anteversion / External Tibial Torsion

26 Conclusions Outcomes after MPFLR = Systematic Review Schneider et al., AJSM % recurrence rate 84% return to Sports Just because MC Hammer could dance like this to You Cant Touch This does not mean you should In particular if you have a history of patellar dislocation

27 Thank You!