Introduction Overview a patella (kneecap) fracture is a traumatic injury caused by direct trauma or rapid contracture of the quadriceps with a flexed knee. treatment is either immobilization or surgery depending on diplacement and knee extension function. it is a serious injury with the potential for long term sequelae. Epidemiology incidence patella fractures account for 1% of all skeletal injuries demographics male to female 2:1 most fractures occur in 20-50 year olds Mechanism of injury direct impact injury occurs from fall or dashboard injury causes failure in compression indirect eccentric contraction occurs from rapid knee flexion against contracted quads muscle causes failure in tension patella sleeve fracture seen in pediatric population (8-10 year olds) high index of suspicion required Associated injuries high-energy dashboard injuries are associated with femoral neck fracture, posterior wall acetabular fracture, or knee dislocation Prognosis osteonecrosis reported to occur in up to 25% but not found to affect clinical outcome Anatomy Osteology patella is largest sesamoid bone in body superior 3/4 of posterior surface covered by articular cartilage articular cartilage thickest in body (up to 1cm) posterior articular surface comprised of medial and lateral facets lateral facet is larger facets separated by vertical ridge Soft tissue attachments quadriceps tendon and fascia lata attach to anterosuperior margin quadriceps tendon comprised of 3 layers superficial layer formed from rectus femoris tendon middle layer formed by vastus medialis and vastus lateralis tendons deep layer formed by vastus intermedius tendon patellar tendon attaches to inferior margin Blood Supply derives from anastomotic ring originating from geniculate arteries most important blood supply to the patella is located at the inferior pole Classification Can be described based on fracture pattern nondisplaced displaced step-off >2-3mm or fracture gap >1-4mm transverse pole or sleeve (upper or lower) vertical marginal osteochondral comminuted (stellate) Presentation History direct blow to knee or extensor mechanism injury Physical exam inspection palpable patellar defect significant hemarthrosis motion unable to perform straight leg raise indicates failure of extensor mechanism retinaculum disrupted can aspirate hemarthrosis and inject local anesthetic if patient unable to perform due to pain provocative tests perform saline load test to rule out open fracture Imaging Radiographs recommended views AP lateral best view to see transverse fx tangential best view to see vertical fx findings fracture displacement degree of fracture displacement correlates with degree of retinacular disruption patella alta Insall-Salvati ratio >1 indicates disruption of patellar tendon patella baja Insall-Salvati ratio <1 indicates disruption of quads tendon CT obtain if suspicion for patellar stress fracture, nonunion, or malunion MRI obtain MRI if child has normal xrays but is unable to straight leg raise Differential Bipartite patella may be mistaken for patella fracture affects 8% of population characteristic superolateral position bilateral in 50% of cases Treatment Nonoperative knee immobilized in extension (brace or cylinder cast) and full weight bearing indications intact extensor mechanism (patient able to perform straight leg raise) nondisplaced or minimally displaced fractures vertical fracture patterns early active ROM with hinged knee brace early WBAT in full extension progress in flexion after 2-3 weeks Operative ORIF indications preserve patella whenever possible extensor mechanism failure (unable to perform straight leg raise) open fractures fracture articular displacement >2mm displaced patella fracture >3mm patella sleeve fractures in children techniques mulitple techniques exist each with pros and cons including tension band construct with k-wires or screws cerglage wire plate and screws partial patellectomy indications comminuted superior or inferior pole fracture measuring <50% patellar height ONLY if ORIF is not possible total patellectomy indications reserved for severe and extensive comminution not amenable to salvage Techniques ORIF with tension band construct approach midline longitudinal incision centered over patella expose articular surface either through fracture site or retinacular rents can alternatively perform lateral parapellar arthrotomy and invertt patella if retinaculum is not damaged or if better visualization of articular surface is desired soft tissue avoid extensive soft tissue dissection to preserve blood supply and viability of skin flaps bone work remove devitalized fragments and loose bodies retain as much of patella as possible instrumentation minifrag lag screw fixation for independent fragments tension band using 0.062 K wires with figure of 8 wire converts tensile forces generated by quads complex at anterior surface into compressive forces at articular surface figure-of-8 typically constructed using 18-gauge stainless steel wire difficult to manipulate and high reoperation rates due to painful hardware or wire migration can alternatively use braided polyester suture found to have 75% tensile strength of 18-gauge stainless steel wire longitudinal cannulated screws combined with tension band wires shown to be biomechanically superior circumferential cerclage wiring good for comminuted fractures interfragmentary screw compression supplemented by cerclage wiring good for comminuted fractures complications painful hardware/anterior knee pain important to tension wire at superior aspect of construct where more soft tissue coverage is available consider using braided polyester suture as opposed to 18-gauge stainless steel wire hardware failure important to tension wire in 2 places to apply equivalent tension in both sides of construct avoid overtensioning wire to prevent articular gapping or wire failure avoid prominent cannulated screw tips that can cause wire failure outcomes modified anterior tension band wiring shown to produce best results Partial patellectomy approach same as ORIF (see above) soft tissue reattach quads or patellar tendon perform with transosseous tunnels or suture anchors with knee in hyperextension reattach as close to articular surface as possible prevents patellar tilt and minimizes contact stresses medial and lateral retinacular repair essential bone work remove devitalized fragments and loose bodies retain as much of patella as possible instrumentation transosseous tunnels or suture anchors to rettach quads or patellar tendon if necessary, reinforce with cerclage suture or wire from quads tendon to tibial tubercle complications weakness outcomes poor outcomes with removal of >40% patella Total patellectomy approach same as ORIF (see above) soft tissue restore integrity of extensor mechanism via imbrication medial and lateral retinacular repair essential consider advancing VMO found to have better strength and outcomes bone work remove all bony fragments complications weakness extensor lag avoid by performing sufficient imbrication outcomes quadriceps torque reduced by 50% Complications Anterior knee pain more common with ORIF Symptomatic hardware (up to 50%) most common more common in open fractures, thought to be due to compromised soft-tissue envelope Hardware Migration has been associated with tension band wiring with K-wires Weakness more common with partial or total patellectomy Loss of reduction (22%) increased in osteoporotic bone Nonunion (<5%) can consider partial patellectomy Osteonecrosis (proximal fragment) thought to be due to excessive initial fracture displacement can observe these, as most spontaneously revascularize by 2 years Infection more common in open fractures Stiffness Hardware failure rare
Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. Patella Fracture ORIF with Tension Band and K Wires Leah Ahn Benjamin C. Taylor Trauma - Patella Fracture
QUESTIONS 1 of 9 1 2 3 4 5 6 7 8 9 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ13.186) A 42-year-old female sustains the injury shown in Figure A as the result of a fall from a ladder. Which of the following is the most common complication after the procedure shown in Figure B? Tested Concept QID: 4821 FIGURES: A B Type & Select Correct Answer 1 Knee arthrofibrosis 3% (104/4089) 2 Symptomatic implant 93% (3815/4089) 3 Implant failure 2% (89/4089) 4 Patella alta 1% (24/4089) 5 Patella baja 1% (29/4089) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review tested concept (OBQ12.43) A 36-year-old female sustains a knee injury after falling from a ladder onto her flexed knee; she cannot do a straight leg raise after a lidocaine injection into her knee. A radiograph is shown in Figure A. Which of the following treatment options has been shown to have the best outcomes with this injury? Tested Concept QID: 4403 FIGURES: A Type & Select Correct Answer 1 Long leg cast 1% (58/4169) 2 Hinged knee brace use with functional rehabilitation protocol 38% (1578/4169) 3 Open treatment with internal fixation or excision with patellar tendon advancement 56% (2350/4169) 4 Distal patellar resection and allograft reconstruction 1% (37/4169) 5 Placement of a cerclage wire from patella to proximal tibia 3% (124/4169) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept (OBQ12.229) A 43-year-old male suffers a knee injury and undergoes the operation seen in Figures A and B. At his one-year follow-up appointment, the patient notes pain in the peri-patellar region that is aggravated by palpation and kneeling. Range-of-motion is from -5 degrees to 130 degrees. A merchant view is performed which shows no significant degenerative changes of the patellofemoral joint. Which of the following treatments would most likely alleviate his pain? Tested Concept QID: 4589 FIGURES: A B Type & Select Correct Answer 1 Symptomatic treatment of his patellofemoral arthritis 1% (41/4769) 2 Manipulation under anesthesia 0% (17/4769) 3 Operative treatment of his non-union 1% (26/4769) 4 Knee intrarticular corticosteroid injection 0% (22/4769) 5 Removal of symptomatic hardware 97% (4643/4769) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review tested concept (OBQ07.207) Partial patellectomy is the recommended treatment for which of the following injuries? Tested Concept QID: 868 Type & Select Correct Answer 1 Vertical patella fractures 1% (9/1238) 2 Bipartite patella 2% (21/1238) 3 Severely comminuted inferior pole fracture 94% (1158/1238) 4 Stellate patella fracture 3% (35/1238) 5 Chronic quadriceps tendon rupture 1% (10/1238) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept
All Videos (2) Podcasts (2) 2018 Orthopaedic Summit Evolving Techniques How I Get Motion After A Patella Fracture: When I Start, What I Do & How I Get My Fracture To Heal - William I. Sterett, MD (OSET 2018) Trauma - Patella Fracture B 8/12/2019 694 views (3) 2019 Orthopaedic Trauma & Fracture Care: Pushing the Envelope Patellar Fracture Treatment - David Friedberg, MD (OTFC 2019, 2.2) David Friedberg Trauma - Patella Fracture A 3/14/2019 2149 views (8) Question Session⎪Patella Fractures & Scaphoid Fractures Orthobullets Team Trauma - Patella Fracture Listen Now 20:36 min 11/6/2019 38 plays (1) Trauma⎪Patella Fracture Team Orthobullets 4 Trauma - Patella Fracture Listen Now 12:15 min 10/15/2019 298 plays (4)
Displaced inferior pole patella fx (C2304) nasim jilani Trauma - Patella Fracture D 7/29/2015 442 4 3 Patella fracture in 59F (C1815) Benjamin C. Taylor Trauma - Patella Fracture A 3/6/2014 12803 14 8 A closed fracture patella without neurovascular deficits (C1107) mital patel Trauma - Patella Fracture E 12/12/2011 92 1 5 See More See Less