PATELLA TBW

TENSION BAND WIRING PRINCIPLES

1. Discuss The Principles Of Tension Band And Describe In Details The Operative Procedure Of TBW Of Patella By Dr Salihi Abdulmalik National Orthopaedic Hospital Dala-Kano 20 th February, 2021

2. Pauwel ; curved tubular structure when subjected to an axial load always present a tension side on the convexity, compression side on the concavity Same seen in a straight bone that is eccentrically loaded Introduction

3. Applying a tension band device laterally (convex side) converts the tensile forces to compression forces provided the opposite side is stable and has good contact Where muscle pull tend to displace fragments; olecranon , patella or avulsion fracture of greater tuberosity , and greater trochanter

4. A tension band will neutralize the distraction forces Under flexion of the joint the fragments will be compressed Absolute stability, flexion exercises possible

5. The tension band device must withstand tensile forces The bone must resist compression (osteoporotic bone, metabolic bone diseases contraindicated) The cortex opposite to the tension band must be exactly reduced without a gap

6. Indications Transverse patella fracture Comminuted fracture that can converted to transverse Displaced fracture > 3 mm displacement >2mm intra articular affectation TBW for patella #

7. Contraindications Osteoporotic bone Metabolic bone disease Missing bone on the concave (compression ) side

8. Types

9. Figure of 8 is superior in neutralizing tension forces Figure of 0 ( Magnudson wiring) has more stability against torsion force though with risk of cerclage wire cutting into the retinacula Figure of 8 vs figure of 0

10. Pre op X rays FBC, U/E/Cr, GXM Consent Sand bag Pointed reduction clamps 1.6-2mm k-wires MATB + figure of 8

11. pre op 18-gauge (or 1.0-1.25mm) circlage wire To avoid bending of k-wire, circlage wire should be at least 2mm less than the k-wire +/- mini fragment screws Suture passer Power drill

12. Intra op Anaesthesia Prophylactic antibiotics Positioning Sand bag under the hip to prevent external rotation of the limb 2 bolsters

13. Anterior longitudinal midline incision Avoid unnecessary undermining of tissue Expose fracture and clear debris Assess degree of injury and define fracture pattern Attempt reduction of fracture with pointed reduction clamp

14. Pass k-wires Antegradely (outside-in technique) Parallel Divide the patella into medial, central and lateral thirds 5mm deep to the anterior aspect of the patella Protrude beyond patella and quadriceps tendon Perform arthrotomy Assess adequacy of reduction To remove pieces of bone/cartilage in the joint Examine the trochlear

15. 18-circlage wire Beneath patellar tendon Cross limbs of wire over anterior patella Pass wire transversely through quadriceps tendon behind the K-wires Tighten wires by twisting both limbs of the wire simultaneously (minimum of 3 turns to avoid breakage) after applying tension

16. Wire should be close to the bone as possible Check reduction by palpating Bend ends of K-wires 180 degree anteriorly Cut excess K-wire Turn remaining end to face posteriorly Impact bent ends of K-wires into the patella

17. Repair retinacular tears with multiple interrupted sutures Arthrotomy is copiously irrigated and closed in water-tight fashion Close wound

18. Post op Analgesics Antibiotics Post op x ray ROM exercises Weight bearing as tolerated on day 1 post o 2-3 weeks wound heals

19. Intra op loss of reduction Malreduction Asymmetric wire tension K-wire migration Prominent hardware Intra- articular penetration Wound breakdown Complications