Updated: 6/11/2021

TKA in Patella Baja (Prior HTO)

0%
Topic
Review Topic
0
0
0%
0%
Flashcards
3
N/A
N/A
Questions
9
0
0
0%
0%
Evidence
23
0
0
0%
0%
Videos / Pods
1
0%
Techniques
3
Topic
Images
https://upload.orthobullets.com/topic/5018/images/patellabaja sp TO_moved.jpg
https://upload.orthobullets.com/topic/5018/images/insallsal.do.jpg
https://upload.orthobullets.com/topic/5018/images/xr patella baja.jpg
  • summary
    • TKA in Patella Baja is characterized by performing a TKA in a patient with a prior high tibial osteotomy that caused lowering of the patella relative to its normal position.
    • Diagnosis can be made with plain radiographs of the knee showing an Insall-Salvati ratio of < 0.8.
    • Treatment of patellar baja in a TKA involves various techniques including lowering the joint line, placing the patellar component superiorly, or performing a tibial tubercle transfer. 
  • Etiology
    • 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 Guides (3)
Flashcards (3)
Cards
1 of 3
Questions (9)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
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?

QID: 607
FIGURES:
1

Notching of the femur

1%

(41/3720)

2

Excessive resection of the distal femur and lateral release of the patella

57%

(2107/3720)

3

Preoperative patella baja

20%

(743/3720)

4

Excessive release of the patellar ligament from the tibial tubercle

4%

(159/3720)

5

Excessive resection of the proximal tibia

18%

(657/3720)

L 3 D

Select Answer to see Preferred Response

(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?

QID: 5973
FIGURES:
1

Fracture

1%

(8/760)

2

Patella baja

72%

(549/760)

3

Patella alta

11%

(81/760)

4

Osteonecrosis

1%

(5/760)

5

Maltracking

15%

(115/760)

L 2 E

Select Answer to see Preferred Response

(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)?

QID: 6018
FIGURES:
1

Bone loss

8%

(55/693)

2

Patella alta

24%

(165/693)

3

Myositis ossificans

2%

(14/693)

4

Fracture

26%

(178/693)

5

Instability

40%

(278/693)

L 4 E

Select Answer to see Preferred Response

(SAE07HK.24) What is the most frequent complication of both lateral closing wedge high tibial osteotomy and medial opening wedge osteotomy?

QID: 5984
1

Patella baja

64%

(585/907)

2

Fracture

16%

(144/907)

3

Peroneal nerve palsy

7%

(62/907)

4

Compartment syndrome

7%

(65/907)

5

Infection

5%

(48/907)

L 2 E

Select Answer to see Preferred Response

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(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?





QID: 1609
1

Joint laxity

12%

(691/5665)

2

Infection

1%

(80/5665)

3

Anterior knee pain

63%

(3571/5665)

4

Quadricep weakness

20%

(1107/5665)

5

Limb lengthening

3%

(188/5665)

L 4 B

Select Answer to see Preferred Response

(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?

QID: 113
1

Collateral ligament instability

10%

(305/3169)

2

Patella alta

8%

(249/3169)

3

Patella baja

78%

(2459/3169)

4

Patellar tendon insufficiency

3%

(81/3169)

5

Severe varus deformity

2%

(63/3169)

L 3 B

Select Answer to see Preferred Response

Evidence (23)
VIDEOS & PODCASTS (3)
EXPERT COMMENTS (11)
Private Note