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Patella fx and mechanism injuries
- 1. Patella Fractures &Extensor Mechanism Injuries Dr P. ROHIT RAJ MBBS MS ORTHO ASSISTANT PROFESSOR ORTHOPAEDIC DEPARTMENT VISHWABHARATHI MEDICAL
- 2. Patella Fractures &Extensor Mechanism Injuries
- 4. Anatomy • Largest sesamoidbone • Thick articular cartilage proximally • Articular surface divided into medial and lateral facets by longitudinal ridge • Distal pole nonarticular
- 5. Anatomy • Patellar Retinaculum –Longitudinal tendinous fibers – Patellofemoral ligaments • Blood Supply – Primarily derived from geniculate arteries
- 6. Biomechanics • The patellais a link between the quadriceps tendon and patella tendon and is subject to significant forces. • The patella increases the leverage of the quadriceps muscle and elevates the extensor mechanism away from the axis of rotation of the knee joint. • The area of contact between the patella and distal femur varies according to the position of the knee.
- 7. Classification • Allows guidancewith treatment • Types – Undisplaced – Transverse – Apex – Comminuted – Vertical – Osteochondral Tip: Vertical fractures may not result in disruption of extensor mechanism
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- 10. Transverse fracture • nondisplaced= medial and lateral retinaculum usually intact • Transverse fractures commonly result in wide fragment separation due to Strong ligamentous traction
- 11. Vertical Fractures • Accountfor 22% of patella fractures* • Typically results from compression of patella with flexed knee • Sometimes only seen on sunrise view
- 12. Stellate Fractures • Resultfrom direct blow • 65% of stellate fractures are displaced • May have associated articular damage to femoral condyles
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- 15. Insall- Salvati ratio, • TheInsall-Salvati ratio or index is the ratio of the patella tendon length to the length of the patella and is used to determine patellar height. • A: patellar tendon length (TL): length of the posterior surface of the tendon from the lower pole of the patella to its insertion on the tibia • B: patellar length (PL): greatest pole-to-pole length • Insall-Salvati ratio = A/B (or TL/PL)
- 16. Interpretation • On plainradiographs: • patella baja: <0.8 • normal: 0.8-1.2 • patella alta: >1.2
- 17. Patella alta • highriding patella, describes a situation where the position of the patella is considered high. It may be idiopathic or may result secondary to a patellar tendon rupture.
- 18. Patellar tendon length(6cm) is > 20% than patellar length (4cm), consistent with a patella alta
- 19. Patella baja • Patellabaja is an abnormally low lying patella, which is associated with restricted range of motion, crepitations, and retropatellar pain. If longstanding, extensor dysfunction may ensue with significant morbidity.
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- 24. Radiographic Evaluation • AP& Lateral – Note patella height (baja or alta) – Note fracture pattern • Articular step-off, diastasis • Marginal impaction • Special views – Axial or sunrise • CT Scan - Occult Fractures - Complex or Marginal Impaction Fractures
- 26. sunrise (skyline) viewof the knee Normal appearing lateral knee radiograph in an elderly patient Sunrise View: Non-displaced Patellar Fracture of the same elderly patient with normal radiographs on the left.
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- 28. Non-displaced patellar fracture. ComminutedPatellar Fracture
- 29. Radiographic Evaluation • BipartitePatella: • Don’t get fooled! – Obtain bilateral views – Often superolateral corner (Saupe Classification, 1923) – Accessory ossification center – Occurs 1-2% of patients
- 32. Operative Treatment • Goals –Preserve extensor function – Restore articular congruency • indicated for displaced fractures and disruption of the extensor mechanism. • Approach – Longitudinal midline incision recommended – Transverse approach alternative (dotted lines) – potentially higher risk wound problems, can limit initiation of ROM – Consider future surgeries!
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- 34. Procedure Reduce & CompressFracture
- 35. Operative Techniques • K-wiresw/ tension band wiring (TBW) • Lag-screw fixation • Cannulated lag-screw with TBW (tension band screw – TBS) • Partial patellectomy • Total Patellectomy
- 36. Tension Band Wiring •Transverse, non-comminuted fractures • Double Figure-8 wire for equal compression
- 37. Tension Band Wiring •Wire converts anterior distractive forces to compressive forces at the articular surface • Retinacular Injury – Keep open until the end – Window to assess articular reduction – Repair the retinacular injury last
- 39. Lag-Screw Fixation • Indicatedfor vertical fractures • Contraindicated for extensive comminution and osteopenic bone
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- 41. Cannulated Lag-Screw With TensionBand (TBS) • Partially threaded cannulated screws (4.0mm) • Wire through screws and across anterior patella in figure of eight tension band • Make sure tip of screw remains buried in bone so it will not compromise wire
- 42. Cannulated Lag-Screw With TensionBand • More stable construct – Screws and tension band wire combination eliminates both possible separation seen at the fracture site with K wire/TBW and screw failure due to excessive three point bending
- 43. Partial Patellectomy • Indicatedfor fractures involving extensive comminution not amenable to fixation • Larger fragments repaired with screws to preserve maximum cartilage • Smaller fragments excised – Usually involving the distal pole
- 45. Total Patellectomy • Indicatedfor displaced, comminuted fractures not amenable to reconstruction • Bone fragments sharply dissected • Defect may be repaired through a variety of techniques
- 49. Complications • Knee Stiffness –Most common complication • Infection – Rare, depends on soft tissue compromise • Loss of Fixation – Hardware failure in up to 20% of cases • Osteoarthritis – May result from articular damage or incongruity • Nonunion < 1% with surgical repair • Painful hardware – Removal required in approximately 15%
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- 53. Extensor Tendon Ruptures •Adolescent- avulsion tibial tubercle • Young adult sports-patellar ligament tear • Middle age adult -fracture of patella • Older people –quadriceps rupture • Mechanism – Fall – Sports “The weekend warrior” – MVA – Tendonopathies, Steroids, Renal Dialysis
- 55. Quadriceps Tendon Rupture •Typically occurs in patients > 40 years old • Usually 0-2 cm above the superior pole • Level often associated with age – Rupture occurs at the bone-tendon junction in majority of patients > 40 years old – Rupture occurs at midsubstance in majority of patients < 40 years old
- 56. Quadriceps Tendon Ruptures •Risk Factors – Chronic tendonitis – Anabolic steroid use – Local steroid injection – Inflammatory arthropathy – Chronic renal failure – Systemic disease
- 57. History • Sensation ofa sudden pop while stressing the extensor mechanism (eccentric load) • Pain at the site of injury • Inability to extend the knee • Difficulty weight-bearing
- 58. Physical Exam • Effusion •Tenderness at the upper pole • Palpable defect above superior pole • Loss of extension • With partial tears, extension will be intact
- 60. MRI • Palpable defectproximal to superior pole of patella • If defect present but patient able to extend the knee then the extensor retinaculum is intact • If no active extension, then both tendon and retinaculum completely torn
- 61. Quadriceps Tendon Rupture RadiographicEvaluation • X-ray- AP, Lateral, and Tangential (Sunrise, Merchant) – Distal displacement of the patella (patella baja) • MRI – Useful when diagnosis is unclear Treatment • Nonoperative – Partial tears and strains • Operative – For complete ruptures
- 62. Nonoperative Treatment Quadriceps TendonRupture • Reserved for incomplete tears in which active, full knee extension is preserved • Immobilize leg in extension for approximately 4-6 weeks • Progressive physical therapy required to regain strength and motion
- 63. Operative Treatment-muscle- tendon junction •Reapproximation of tendon to bone using nonabsorbable sutures with tears at the muscle-tendon junction • Early primary repair of quadriceps tendon ruptures in recommended
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- 67. mid substance tear– acute -Scuderi technique • The Scuderi technique for repairing acute tears of the quadri- ceps tendon. • (A) The torn edges of the quadriceps tendon are debrided and repaired. • (B) A triangular flap of the proximal tendon is developed, folded distally over the rupture, and sutured in place
- 69. chronic Treatment • Chronic tearsmay require a V-Y advancement of a retracted quadriceps tendon (Codivilla V- Y-plasty Technique)
- 70. Postoperative Management • Immediateweight-bearing as tolerated • Knee immobilizer, Hinged Knee Brace, or cylinder cast for 5-6 weeks
- 71. Complications • Re rupture •Persistent quadriceps atrophy/weakness • Loss of motion • Infection
- 72. Patellar Tendon Rupture •Less common than quadriceps tendon rupture • Associated with degenerative changes of the tendon • Rupture often occurs at inferior pole insertion site
- 73. Patellar Tendon Rupture •Risk Factors – Rheumatoid arthritis – Systemic Lupus Erythematosus – Diabetes – Chronic Renal Failure – Systemic Corticosteroid Therapy – Local Steroid Injection – Chronic tendonitis
- 74. History • Often areport of forceful quadriceps contraction against a flexed knee • May experience and audible “pop” • Inability to weight bear or extend the knee
- 75. Physical Examination • Palpabledefect • Hemarthrosis • Painful passive knee flexion • Partial or complete loss of active extension • High riding patella on radiographs (patella alta) • Quadriceps atrophy with chronic injury
- 77. Radiographic Evaluation • APand Lateral X-ray – Patella alta seen on lateral view • Patella superior to Blumensaat’s line • Ultrasonagraphy – Effective means to confirm diagnosis by determining continuity of tendon – Operator and reader dependant • MRI – Effective means to assess patellar tendon, especially if other intraarticular or soft tissue injuries are suspected – Relatively high cost
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- 79. Classification • No widelyaccepted means of classification • Can be categorized by: – Location of tear • Proximal insertion most common – Timing between injury and surgery • Most important factor for prognosis • Acute: < 2 weeks • Chronic: > 2 weeks
- 81. Nonoperative Treatment of PatellarTedon Rupture • Nonoperative treatment reserved for partial tears in which patient able to fully extend knee • Treatment is immobilization in full extension for 3-6 weeks
- 82. Operative Treatment • Surgicaltreatment is required for restoration of the extensor mechanism • Better overall outcome • Primary repair of the tendon • Surgical approach is through a midline incision
- 83. osteotendinous junction • For ruptureat osteotendinous junction, tendon reattached to patella with heavy, nonabsorbable sutures passed through drill holes in patella • Medial and lateral retinacula repaired with heavy absorbable suture • Knee immobilized in extension for 6 weeks
- 85. Postoperative Management • Moreconservative when compared to early repair • Bivalved cylinder cast for 6 weeks; may start passive range of motion • Active range of motion is started at 6 weeks
- 86. Complications • Knee stiffness •Persistent extensor weakness • Rerupture • Infection • Patella baja (Insall-Salvati ratio of < 0.8)
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