Patella Instability 1 st Time Dislocation American Medical Society for Sports Medicine April 6, 2014 Beth E. Shubin Stein, MD Sports Medicine & Shoulder Surgery Hospital for Special Surgery
Beth E. Shubin Stein, MD Hospital for Special Surgery Disclosure: I DO NOT have a financial relationship with any commercial interest.
What is the Problem???
THIS IS THE PROBLEM
Factors contributing to stability Articular geometry Soft tissue stabilizers Static Dynamic Patella Stability
Patella Stability Articular geometry Trochlea Patella
Patella Stability Trochlear Dysplasia
Patella Stability Patella Alta
Patella Stability TT-TG
Patella Stability Soft tissue stabilizers Medial patellofemoral ligament
MPFL Anatomy Originates saddle between adductor tubercle and medial epicondyle Inserts medial patella Blends with the deep fascia of the VM the passive and dynamic stabilizers may act in concert
MPFL Biomechanics Restraint to lateral translation MPFL 60% Lateral retinaculum 10% Desio et al
Patella Stability Dynamic Stabilizers Vastus medialis
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
Acute Patellar Dislocation Physical Exam Effusion Tenderness and ecchymosis medially over adductor tubercle Apprehension*** R/O ACL, MCL injury Same MOI
Axial radiograph *best view for tilt or subluxation Lateral radiograph Patella height Trochlear morphology MRI Cartilage lesions Ligament damage TT-TG Imaging
Acute Patellar Dislocation MRI
Acute Patellar Dislocation Predisposing Factors Patella alta VMO dysplasia Increased Q angle Contracted ITB Valgus knee deformity Hypoplastic lateral condyle
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
Natural History Non-Operative Treatment Epidemiology and Natural History of Acute Patellar Dislocation Fithian et al. Am J Sports Med 2004 32: 1114 17 % after 1 st dislocation ~50% after 2 nd dislocation
What is the Problem? Chondral injury Medial facet patella Lateral trochlea
Not always clear 1 st time dislocators Who Needs Surgery? Non op treatment (unless Osteochond fx/ loose body) **Recurrent dislocators Atraumatic Traumatic
Am J Sports Med. 2013 Mar Predictors of recurrent instability after acute patellofemoral dislocation in pediatric and adolescent patients. Lewallen LW, McIntosh AL, Dahm DL.
Proximal realignment Patellar Instability Surgical Options Acute repair MPFL Open/Arthroscopic imbrication MPFL reconstruction Distal realignment Tibial tubercle transfer Both
Patellar Instability Surgical Options Proximal realignment Acute repair MPFL Open/Arthroscopic imbrication MPFL reconstruction Distal realignment Tibial tubercle transfer Both
Patellar Instability Surgical Options Proximal realignment Acute repair MPFL Open/Arthroscopic imbrication MPFL reconstruction Distal realignment Tibial tubercle transfer Both
Patellar Instability Surgical Options Proximal realignment Acute repair MPFL Open/Arthroscopic imbrication MPFL reconstruction Distal realignment Tibial tubercle transfer Both
Patellar Instability Surgical Options Proximal realignment Acute repair MPFL Open/Arthroscopic imbrication MPFL reconstruction Distal realignment Tibial tubercle transfer Both
Proximal realignment Patellar Instability Surgical Options Acute repair MPFL Open/Arthroscopic imbrication MPFL reconstruction Distal realignment Tibial tubercle transfer Both
Patellar Instability Surgical Options Proximal realignment Acute repair MPFL Open/Arthroscopic imbrication MPFL reconstruction Distal realignment Tibial tubercle transfer Both Trochleaplasty
MPFL Repair
MPFL repair Indications 1 st time dislocation loose body osteochondral fracture Goals Same as reconstruction Restore anatomy Restore biomechanics/function Optimize strength of fixation
Imaging MRI
Arthroscopy
Results Acute MPFL Repair Salley et al AJSM 1996 Open MPFL repair 16 patients Ave follow-up 34 mos No recurrent dislocations
Results Acute MPFL Repair Ahmad et al AJSM 2000 Open MPFL and VMO repair 8 patients Ave f/u 3.0 years No recurrent dislocations Ave Kujala score was 91.9 Return to 86% of their pre-injury athletic level Subjective satisfaction was 96%
MPFL Reconstruction
Imaging MRI
MPFL Reconstruction
MPFL Reconstruction
Post Op Radiographs Pre-op
Results MPFL Reconstruction Steiner et al AJSM 2006 34 patients Multiple grafts Min 2yr f/u; mean 66.5 mos No recurrent dislocations 85% kujala; 91% lysholm G/E ** in patients with TROCHLEAR DYSPLASIA
20 patients Results MPFL Reconstruction The Docking Technique for Medial Patellofemoral Ligament Reconstruction Surgical Technique and Clinical Outcome Christopher S. Ahmad, MD, Gabriel D. Brown, MD, and Beth Shubin Stein,MD -AJSM 2009 Min f/u 24 mos; avg 31 mos No recurrent dislocations or subluxations Kujala 88; Lysholm 89
EUA
Arthroscopy
Proximal/ Distal Realignment
Proximal/ Distal Realignment
Thank You