Patellofemoral Instability Jacqueline Munch, MD April 23, 2016

Transcription

1 Patellofemoral Instability Jacqueline Munch, MD April 23, 2016 With many thanks to Beth Shubin Stein, MD

2 What is the Problem???

3 THIS IS THE PROBLEM

4 Patella Stability Factors contributing to stability Articular geometry Soft tissue stabilizers Static Dynamic

5 Patella Stability Articular geometry Trochlea Patella

6 Patella Stability Trochlear Dysplasia

7 Trochlear Dysplasia Dejour A = shallow Dejour C = dominant lateral Dejour B = flat Normal Dejour D = cliff

8 Patella Stability Patella Alta

9 Patella Alta Patella fails to engage trochlea appropriately

10 Coronal Plane Alignment Q Angle Patient/limb positioning Contraction of the quadriceps Identification of bony landmarks

11 Patella Stability TT-TG

12 Patella Stability Soft tissue stabilizers Medial patellofemoral ligament (MPFL)

13 MPFL Anatomy Originates saddle between adductor tubercle and medial epicondyle Inserts medial patella Blends with the deep fascia of the VMO the passive and dynamic stabilizers may act in concert

14 MPFL Biomechanics Restraint to lateral translation MPFL 60% Lateral retinaculum 10% Desio et al

15 Patella Stability Dynamic Stabilizers Vastus medialis

16 Other Risk Factors Rotational malalignment Ligamentous laxity Jumping/landing mechanics rbilt.org/services.php?mid=2166

17 Acute Patellar Dislocation History 2 nd and 3 rd decade Twisting non-contact injury Rapid effusion Locking catching Men=Women *They do not tell you they dislocated

18 Acute Patellar Dislocation Physical Exam Effusion Tenderness and ecchymosis medially over adductor tubercle Apprehension*** J sign Caution: ACL, MCL injury Same mechanism

19 MRI Cartilage lesions Ligament damage TT-TG Imaging Axial radiograph *best view for tilt or subluxation Lateral radiograph Patella height Trochlear morphology

20 Acute Patellar Dislocation MRI

21 Acute Patellar Dislocation Predisposing Factors Patella alta VMO dysplasia Contracted ITB Increased Q angle Valgus knee deformity Hypoplastic lateral condyle

22 Characteristics of Patients with Primary Acute Lateral Patellar Dislocation: their Recovery within the First 6 Months of Injury Atkin, Fithian et al AJSM 2000 Few patients had abnormal physical features, contradicting the stereotype of a overweight, sedentary, adolescent girl whose patella dislocates with little or no trauma

23 Natural History Non-Operative Treatment Epidemiology and Natural History of Acute Patellar Dislocation Fithian et al. Am J Sports Med : % after 1 st dislocation ~50% after 2 nd dislocation

24 What is the Problem? Chondral injury Medial facet patella Lateral trochlea

25 Who Needs Surgery? Not always clear Rarely 1 st time dislocators Fracture/loose body Skeletally immature? Hold that thought **Recurrent dislocators

26 Options for Stabilization Soft tissue stabilization Bony realignment

27 Lateral Release

28 Medial patellofemoral ligament 60% restraint to lateral patellar translation

29 Soft Tissue Stabilization MPFL Repair 46% rate of recurrent dislocation!

30 Soft Tissue Stabilization Reconstruction Medial PatelloFemoral Ligament (MPFL) MQTFL Fulkerson Ronga et al 2009

31 Bony Realignment Tibial tubercle osteotomy Medializing Anteromedializing Distalizing

32 Trochleoplasty David Dejour et al 2013 For grades B and D

33 How Do We Decide Which Procedure(s) to Use?

34 Current Indications for Distal Realignment Patella alta TT-TG > mm

35 Study #1: Recurrent Instability Prospective cohort: MPFL reconstruction No randomization Exclusion criteria: Grade IV cartilage lesion Previous soft tissue stabilization procedure

36 Skeletal Maturity Distal femoral physis Apparent at birth Closes 14-16F, 16-18M Tibial tubercle apophysis Develops ~8 years Closes 13-15F, 15-19M

37 Skeletal Maturity Significant predictors of recurrence: Skeletal immaturity (open/closing physes) Trochlear dysplasia Skeletally immature patients with trochlear dysplasia = 68.8% risk of recurrence!!

38 Secondary Trochlear Dysplasia

39 Study #2: Skeletally immature first-time dislocators PAPI: Pediatric and Adolescent Patellofemoral Instability Randomize to surgery vs. no surgery MPFL reconstruction Standardized physical therapy protocols

40

41 This area is ripe for study in the United States! Prospective, randomized, controlled data. Multicenter collaboration Appropriate surgical intervention. MPFL reconstruction Evaluation of need for bony realignment. Consideration of multiple risk factors. Please lend us your support!

42 Thank You Questions?

43 Am J Sports Med Mar Predictors of recurrent instability after acute patellofemoral dislocation in pediatric and adolescent patients. Lewallen LW, McIntosh AL, Dahm DL.