Introduction Patella baja is characterized by lowering of the patella relative to its normal position may be congenital or acquired (this topic) Pathophysiology of acquired patella baja common causes include proximal tibial osteotomy patella baja is the most common complication seen following proximal tibial opening-wedge osteotomy may be caused by shortening of the patellar tendon during tibial osteotomy or from scarring of the patellar tendon post-operatively tibial tubercle slide or transfer trauma to the proximal tibia technical error during primary total knee replacement (joint line elevation) ACL reconstruction Associated conditions total knee arthroplasty patella infera is an important consideration when performing total knee arthroplasty improper technique may cause patella baja special techniques must be utilized when performing TKA in patients with patella baja from congenital or acquired (tibial osteotomy, prior TKA) causes Presentation Symptoms anterior impingement knee pain knee stiffness Physical exam mechanical block to full flexion limited flexion due to patellar impingement on the tibia in extremes of flexion Imaging Radiographs recommended views AP and lateral views of the knee lateral view of the knee in 30 degrees of flexion used to measure Insall-Salvati ratio measures ratio patellar tendon length to patellar bone length normal Insall-Salvati is 1:1 between length of the patellar tendon length to patellar bone length findings lateral view in extension distal positioning of the patella in relation to the trochlear groove Insall-Salvati ratio of < 0.8 is consistent with patella baja Treatment Nonoperative activity modifications, physical therapy indications mild symptoms in younger patients Operative total knee replacement indications severe impingement in older patients with osteoarthritis Techniques Total knee arthroplasty in patient with patella baja methods to address patella infera during TKA place patellar component superiorly indications mild patella baja technique use a smaller patellar dome placed on superior aspect of patella trim inferior bone to decrease flexion impingement lower joint line indications moderate patella baja technique add distal femoral augmentation cut more proximal tibia to lower joint line (lower tibial cut) avoid bone cuts that raise the joint line raising the joint line will effectively increase the patella baja deformity may require revision knee system transfer tibial tubercle to cephalad position indications moderate patella baja technique technique is difficult due to complexity of a tibial transfer in proximity to a cemented tibial component outcomes unpredictable bone healing leads to variable, and often poor, outcomes patients may be left with extensor lag patellectomy indications severe patella baja techniques alters the tension in the anterior knee mechanism therefore recommended to use use a cruciate substituting system consider partial patellectomy in which patella is resected to a width of 10-12mm. lessens impingement & crepitus while maintaining some of the fulcrum of the patella.
Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. TKA - Parapatellar Approach Derek Bernstein Stephen Incavo Recon - High Tibial Osteotomy Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. TKA - Varus Knee with Anterior Referencing and Gap Balancing Technique Derek Bernstein Stephen Incavo Recon - TKA Axial Alignment Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. TKA with Computer Navigation & Sensor-Guided Assessment for Soft Tissue Balancing - Dr. William Gall William Gallivan Recon - TKA Axial Alignment
QUESTIONS 1 of 8 1 2 3 4 5 6 7 8 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ08.221) A 70-year-old female has persistent anterior knee pain and stiffness 10 months status-post total knee arthroplasty with associated lateral patellar release. Radiographs before and after surgery are shown in Figures A and B respectively. Pre-operatively, her Insall-Savati ratio is 0.95, compared to 0.76 post-operatively. Which of the following is the most likely cause of her radiographic abnormality and pain? Tested Concept QID: 607 FIGURES: A B Type & Select Correct Answer 1 Notching of the femur 1% (36/3527) 2 Excessive resection of the distal femur and lateral release of the patella 57% (2006/3527) 3 Preoperative patella baja 20% (701/3527) 4 Excessive release of the patellar ligament from the tibial tubercle 4% (152/3527) 5 Excessive resection of the proximal tibia 18% (619/3527) L 3 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review tested concept Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.58) Figure 35 shows the AP radiograph of a patient who underwent a previous upper tibial osteotomy (UTO). The patient may be at risk for which of the following during total knee arthroplasty (TKA)? Tested Concept QID: 6018 FIGURES: A Type & Select Correct Answer 1 Bone loss 8% (49/611) 2 Patella alta 23% (138/611) 3 Myositis ossificans 2% (14/611) 4 Fracture 26% (159/611) 5 Instability 41% (249/611) L 4 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review tested concept This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.24) What is the most frequent complication of both lateral closing wedge high tibial osteotomy and medial opening wedge osteotomy? Tested Concept QID: 5984 Type & Select Correct Answer 1 Patella baja 66% (505/765) 2 Fracture 16% (119/765) 3 Peroneal nerve palsy 6% (43/765) 4 Compartment syndrome 7% (55/765) 5 Infection 5% (40/765) L 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review tested concept This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.13) A 60-year-old patient had the procedure shown in Figure 7 performed 5 years ago. When converting this patient to a total knee arthroplasty (TKA), what patellar problem is commonly encountered intraoperatively? Tested Concept QID: 5973 FIGURES: A Type & Select Correct Answer 1 Fracture 1% (8/652) 2 Patella baja 73% (476/652) 3 Patella alta 10% (67/652) 4 Osteonecrosis 1% (5/652) 5 Maltracking 14% (94/652) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review tested concept (SBQ07HK.24) A 25-year-old healthy, active male undergoes lateral closing wedge high tibial osteotomy. Which of the following complaints is most commonly associated with this procedure? Tested Concept QID: 1609 Type & Select Correct Answer 1 Joint laxity 12% (655/5378) 2 Infection 1% (77/5378) 3 Anterior knee pain 63% (3380/5378) 4 Quadricep weakness 20% (1057/5378) 5 Limb lengthening 3% (182/5378) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept (OBQ04.2) A patient who has previously undergone a high tibial osteotomy 10 years prior is scheduled for a total knee arthroplasty (TKA). Which of the following factors is most likely to be present and may complicate the arthroplasty? Tested Concept QID: 113 Type & Select Correct Answer 1 Collateral ligament instability 9% (277/2988) 2 Patella alta 8% (235/2988) 3 Patella baja 78% (2333/2988) 4 Patellar tendon insufficiency 3% (75/2988) 5 Severe varus deformity 2% (56/2988) L 3 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept
All Videos (1) Podcasts (2) Login to View Community Videos Login to View Community Videos 2017 Orthopaedic Summit Evolving Techniques Converting the Osteotomized Knee to a TKA: Beware! How to Get a Good Result - Michael Bolognesi, MD Michael Bolognesi Recon - TKA in Patella Baja (Prior HTO) 4/30/2018 148 views (0) Recon ⎜ TKA in Patella Baja Team Orthobullets (AF) Recon - TKA in Patella Baja (Prior HTO) Listen Now 8:24 min 10/16/2019 19 plays (1) Recon⎪TKA in Patella Baja (Infera) Orthobullets Engineer (admin) Recon - TKA in Patella Baja (Prior HTO) Listen Now 9:53 min 10/15/2019 86 plays (1)