Where are we now? A little bit of History.. Is menu à la carte relevant in 2019? Medial PatelloFemoral Ligament the Queen of the PF Joint

Transcription

1 Surgical Algorithm for PF Stablization Can we get there? Elizabeth A. Arendt, M.D. Professor & Vice Chair University of Minnesota, USA Department of Orthopedic Surgery A little bit of History.. TRIA 4 Principal PF Instability Factors 1987 H. Dejour, G. Walch Control (n= 190) / Dislocation (n= 147) Surgical Correction «menu à la carte» TT- TG > 20 mm 56% Trochlear dysplasia 96% Recurrent patellar dislocations Tilt >20 30% 1 % Recurrence 14 % Residual Pain Without an MPFL Reconstruction Serie de 216 Patients Service H. DEJOUR French J. Orthop Knee Surg. Trauma % Patella Alta > 1.2 Compliments of David Dejour Where are we now? Is menu à la carte relevant in 2019? Let s review what we know Medial PatelloFemoral Ligament the Queen of the PF Joint MPFL-R Cornerstone of Patella stabilizing procedures MPFL MPFL 1

2 Anatomic Patella Instability Factors in First Time LPD Patella alta and trochlear dysplasia predominated. TT-TG less represented, and never as a single factor (N=159: MR measurements) Arendt, et al. KSST, 2016 Kruckeberg, Arendt, Laprade, et al., AJSM (2018) Trochlear dysplasia and lateral patella tilt predominated, followed by patella alta. TT-TG less common, and never as a single factor (N=107: MR measurements) Askenberger, Arendt,et al. AJSM, 2016 Abnormal APIF Primary LPD # Risk Factors # Pts TD C/D Lateral Tilt TT-TG Totals When to correct other factors? Important!! Anatomic (imaging) factors risk for primary & recurrent lateral patella dislocations. We do not know if these factors have to be surgically corrected for best results. MPFL Reconstruction: Surgical Indications what about other factors?? Trochlear dysplasia Increased Q- angle Increased TT-TG Patella Alta Increased lateral patella tilt Systematic Review : Clinical Studies of Isolated MPFL Recon. 24 studies : published in yr (12/ 50% in year ) 850 knees from 819 patients 17 of 24 with min. 2 yr. F/U 88% reported Trochlear Dysplasia but in 3 different ways Sulcus angle, TD classification, trochlear depth 53% reported on patellar height ( 1º I/S) Arendt, Tompkins: AJSM,

3 Systematic Review : Clinical Studies of Isolated MPFL Recon. In 8 studies, a heterogenous population was included (ie) patients w/ patella alta, TT-TG, and TD. Only 2 studies related any outcome metric to pre-operative variables, in particular, anatomic imaging risk factors. Matsushita T, Kuroda R, et al. KSSTA 2014 Recurrent patellar dislocation: 34 patients TT-TG distance of >20 mm may not be an absolute indication for medialisation TT-TG distance >20mm TT-TG distance <20mm of the tibial (n=19) tuberosity when VS performing (n=15) MPFL reconstruction No re-dislocation Same clinical score Recent reports on TT-TG & MPFL reconstruction Nelitz et al., Am J Sports Med 2013 Outcomes of MPFL reconstruction in young patients including patients with predisposing factors Wagner et al., KSSTA 2013, Kita et al., Am J Sports Med 2017 Influences of patellar alta, TT-TG distance, trochlear dysplasia on clinical outcomes of MPFL reconstruction TT-TG did not significantly affect Kujala Scores Matsushita, et al., KSSTA 2014 Recent reports on TT-TG & MPFL reconstruction Trochlear groove morphology Has a greater role than TT-TG distance in MPFL reconstruction outcomes Clincal outcomes of MPFL-R in patients w/ increased TT-TG No re-dislocation, same clinical score, between 2 groups What about TT-TG Trochlear Dysplasia: with high grade trochlear dysplasia, the proximal sulcus is relatively medialized > TT-TG distance. When to medialize the tibial tubercle? Medial trochlear hypoplasia 3

4 Quaricep Vector Role of Medial Tibial Tubercle Transfer Too much (medial) decrease in Q-angle causes increase in medial patella facet loading. Huberti et al., JBJS 1984 Role of Medial Tibial Tubercle Transfer Increase in medial compartment arthrosis compared to opposite knee in patients who have medialization of the tibial tubercle. A little bit of History.. Bandi-Maquet Elmslie-Trillat PAIN INSTABILITY Sanfridsson et al., Acta Radiologica 2001 and Kuroda, ISSACUS Meeting, 2001 Maquet, 1976 Trillat, 1964 AMZ Treatment for PF Chondral Lesions Load shifting operation Anteromedialization (AMZ) : Symptomatic cartilage lesion INFERIOR/LATERAL Fulkerson, CORR

5 Technical Aspect of Medial TTO Medial Tibial Tubercle Transfer when do I add it to MPFL-R? Medial TT osteotomy Regardless of TT-TG value Correct no more than to have a tubercle sulcus angle zero TT-TG (20-24 mm) and there is overload of the lateral patella facet (early chondrosis) No tightness laterally 0 can t release or lengthen With a distalization when TT-TG is Patella Alta Biomechanical Considerations In patella alta: PF contact area is diminished in the first 60 degree of flexion PF protection by trochlea walls is later in the flexion arc Patella Alta Biomechanical Considerations Reduced PF contact area increase in PF stress This force is concentrated on the inferior lateral patella 5

6 Patella Alta Biomechanical Considerations Patella Position (Radiographs) Sagittal plane Tibial based Caton Deschamp s Index Insall Salvati Ratio Patella Alta I/S > 1.3 C/D > 1.2 Consider Distal TTO C/D > 1.3 Both knees have instability Knee hyperextension > 10º + J sign w/ alta ADL s are affected Then look to Engagement B A D C Patella Position on MRI slice imaging Sagittal plane Femoral Based Biedert-Albrecht Index Patella Trochlea Index Compares distal patella / superior trochlear cartilage overlap Functional Engagement D E Patella Position MRI slice imaging Sagittal plane Femoral Based Patella Trochlear Index /-.05 * (controls, n=81) /-.3 * (LPD, n=40) Alta : < ** (1/8) P T PTI = T / P * Charles et al., AJSM 2012 ** Biedert, Albrecht, KSST 2006 Spectrum of Trochlear Dysplasia Very short Trochlea Big STS Trochlear depth/length OK

7 Patella Alta Empty Sulcus Sign Distal Tibial Tubercle Osteotomy when is it necessary? Patella height : lateral radiographs excessive : > 1.3 tibial based measurements ( I/S & C/D) Functional Engagement : My rule of thumb: 20% overlap Empty sulcus sign Distal Tibial Tubercle Osteotomy when do I think about a distal TTO? Functional Engagement < 25 % Includes trochlear length C/D > 1.4, threshold less when: Bilateral PF instability, Knee hyperextension > 10º + J sign w/ alta ADL s are affected I/S 1.17 I/S 1.17 C/D

8 I/S 1.17 C/D 1.42 Slice imaging C/D = 1.1 I/S = 1.35 Trochlear depth: 2 mm by Axial MRI Case 1 C/D 1.2 Trochlear depth: 2 mm Patella-trochlear: minimal overlap I/S. 1.4 Case 1 Case 2 Patella-Trochlea Index nearly 0 Case 2 Case 2 8

9 Case 2 Varus Osteotomy for Genu Valgum when is it necessary? Rare in adults for Rx. PF instability Lateral TF joint at risk (should be) common in kids Guided growth Limb Torsion External Tibial Torsion Femoral Anteversion kissing kneecaps w/ toes forward? Apparent tibial varum Trochleoplasty When is it necessary? Take home messages Individualize treatment weighing patient/ activity/ imaging factors Patella Height Use more than one method Look at engagement (considers groove length) Reconsider the value of TT-TG correction 9

10 Take home messages How has the Menu changed? yes Not need to correct all anatomic instability factors Still seeking the Holy Grail Thresholds to add a bony procedure for surgical patellar stabilization more narrow with MPFL-R Redefining the role of genu valgum / limb torsion Thank you 10