Disclosures. Tenodesis Screw Fixation of Tendon Graft for Scapholunate Dissociation: Biomechanical Analysis of a New Surgical Technique

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1 Tenodesis Screw Fixation of Tendon Graft for Scapholunate Dissociation: Biomechanical Analysis of a New Surgical Technique Disclosures None Jun Y. Matsui, M.D. Safa Herfat, Ph.D. Lisa Lattanza, M.D. UCSF Orthopaedic Surgery Inman Abbott Conference May 10, 2013 Outline Introduction Methods Results Preliminary Discussion Introduction - Scapholunate Anatomy Osseous Ligamentous Volar Dorsal Short, JHS 2009 Mitsuyasu, JHS 2004 Elsaidi, CORR 2004 Viegas, JHS

2 Introduction Scapholunate Dissociation SLAC Complete SL dissociation Primary repair Capsulodesis RASL Ligament reconstruction Intercarpal fusions (salvage) Meade at al. J Hand Surg 1990 Pollock et al, J Hand Surg 2010 Our technique: the beginning Goals Withstands stress over time Stronger fixation Reduce technical challenge of the scaphoid tunnel All-dorsal approach Tenodesis screws 2

3 3mm tenodesis screws Methods 6 paired cadaver specimen Free of pre-existing wrist injury SL diastasis and DISI: SLIL, DRC, DIC or new technique Repetitive grip loaded in jig with 100N load Fatigue tested Interval measurements scapholunate gap and angle Meade at al. J Hand Surg 1990 Pollock et al, J Hand Surg 2010 Elsaidi, CORR 2004 Mitsuyasu, J Hand Surg 2004 Short, J Hand Surg 2009 Finger flexors (8) connected to materials testing machine Fingers attached to 2.5lb weight Materials testing machine raises and lowers to achieve full grip and extension Wrist extensors (3) attached to 10lb weight 3

4 Preliminary Results 2 pairs Evidence of dynamic gap at 100 cycles Static gap at 200 cycles New technique No evidence of gap or DISI at 5000 cycles Cycles Gap: 1.64 Angle: Gap: 3.92 Angle: 55 Gap: 3.35 Angle: 48 Gap: 4.05 Angle: Gap: 1.87 Angle: 53 Gap: 2.03 Angle: 52 Gap: 1.91 Angle: 53 Discussion New technique: SLIL and DIC Fixation Eliminates tunnel Auto or allograft options Leaves unsolved DRC did not want to cross the wrist Volar ligaments Effect of healing, scarring 4

5 Future Studies: Clinical Long term follow up Pain Arthritis Grip strength Wrist range of motion Scapholunate gap, angle Prospective randomized clinical trial Conclusions When there are >5 proposed procedures for the same problem, there is no right answer yet This new technique potentially reduces surgical morbidity, restores dorsal anatomy which is the most important, and allows for tendon-bone healing Biomechanical studies should be followed by clinical studies References Bleuler P et al. Dynamic repair of scapholunate dissociation with dorsal extensor carpi radialis longus tenodesis. J hand Surg 2008; 33A: Boileau P et al. Arthroscopic treatment of isolated Type II SLAP lesions: biceps tenodesis as an alternative reinsertion. Am J Sports Med 2009; 37 (5): Brunelli GA, Brunelli GR. A new technique to correct carpal instability with scaphoid rotary subluxation: A preliminary report. J Hand Surg [Am] 1995; 20:S82-S85. Chabas JF et al. Results of the Tenodesis for Treatment of Scapholunate Instability: A Retrospective Study of 19 Patients. J Hand Surg 2008: 33A: Golish SR et al. Interference screw versus suture anchor fixation for subpectoral tenodesis of the proximal biceps tendon: a cadaveric study. Arthroscopy 2008; 24(10): Heinzelmann AD et al. A combined technique for distal biceps repair using a soft tissue button and biotenodesis intererence screw. Am J Sports Med 2009; 37: 989. Howlett JPC et al. Distal tunnel placement improves scaphoid flexion with the Brunelli tenodesis procedure for scapholunate dissociation. J Hand Surg 2008; 33A: Kuo CE and Wolfe SW. Scapholunate Instability: Current concepts in diagnosis and management. J Hand Surg 2008; 33A: Kusma et al. Tenodesis of the long head of the biceps brachii: Cyclic testing of five methods of fixation in a porcine model. J shoulder Elbow Surg 2008; 17: Lee SK et al. Fixation of tendon grafts for collateral ligament reconstructions: A cadaveric biomechanical study. J Hand Surg 2005; 30A: Links AC et al. Scapholunate Interosseous Ligament Reconstruction: results with a Technique versus Four-Bone Weave. J Hand Surg 2008; 33A: Marcuzzi A et al. Ligamentous reconstruction of scaphlunate dislocation through a double dorsal and palmar approach. J Hand Surg 2006; 31B (4): Mazocca AD et al. Biomechanical evaluation of 4 techniques for distal biceps brachii tendon repair. Am J Sports Med 2006; 35 (2): Millet PJ et al. Interference screw vs. suture anchor fixation for open subpectoral biceps tenodesis: Does it matter? BMC Musculoskel Disord 2008; 9:121. Ozalay M et al. Mechanical Strength of Four Different Biceps Tenodesis Techniques. Arthroscopy 2005; 21(8): THANK YOU! Dr. Lisa Lattanza Safa Herfat, Ph. D. Erik McDonald, B.S. Jenni Buckley, Ph.D. 5