What is the recommended management for patellar maltracking?

Management of Patellar Maltracking

The management of patellar maltracking depends critically on whether instability is present: isolated maltracking without instability requires corrective osteotomy to address underlying anatomic abnormalities, while maltracking with instability necessitates MPFL reconstruction combined with correction of specific anatomic deformities such as patella alta, excessive TT-TG distance, or trochlear dysplasia. 1

Initial Diagnostic Assessment

Radiographic evaluation is the cornerstone of diagnosis:

• Obtain standard anteroposterior and lateral knee radiographs as first-line imaging 2
• Add weight-bearing axial radiographs to accurately assess patellofemoral kinematics and degree of patellar tilt or subluxation 2
• CT with metal artifact reduction techniques is the preferred modality for measuring component malrotation when prostheses are present, or for detailed assessment of bony anatomy when surgical planning is needed 2, 3
• MRI can detect subtle features of maltracking and underlying structural abnormalities, particularly valuable when there is no clear history of patellar dislocation 4

Classification-Based Treatment Algorithm

The treatment approach must be tailored to the specific type of patellar pathology present 1:

Type 1 (Simple traumatic dislocation without maltracking):

• Conservative management is appropriate given low redislocation risk 1

Type 2 (Instability without maltracking):

• MPFL reconstruction alone is indicated and sufficient 1
• Nonresorbable suture tape reconstruction can normalize patellar tracking independent of patella-side fixation technique (anchor-based or soft-tissue fixation) 5

Type 3 (Instability WITH maltracking):

• MPFL reconstruction alone is insufficient 1
• Identify and correct the specific anatomic cause of maltracking:
  • Patella alta: Requires distal tibial tubercle transfer 6, 1
  • Excessive TT-TG distance: Requires medial tibial tubercle transfer 6, 1
  • Soft tissue contracture: Requires lateral release 6
  • Valgus deviations or torsional deformities: Require corrective osteotomy 1
• Consider anteromedialization (AMZ) tibial tubercle osteotomy over pure medialization (Elmslie-Trillat), as AMZ significantly decreases contact forces across both lateral and medial patellar facets, preventing medial compartment overload 7
• Add vastus medialis obliquus advancement to optimize dynamic stabilization 6

Type 4 (Severe trochlear dysplasia with "floating patella"):

• Trochleoplasty is the treatment of choice, combined with bony and soft-tissue procedures as needed 1

Type 5 (Maltracking without instability):

• Corrective osteotomy is required to address the underlying anatomic abnormality 1
• MPFL reconstruction is not indicated 1

Critical Pitfalls to Avoid

Do not perform isolated MPFL reconstruction when maltracking is present - this will fail to address the underlying anatomic pathology and lead to poor outcomes 1. The presence of maltracking mandates identification and correction of specific anatomic abnormalities (patella alta, excessive TT-TG distance, trochlear dysplasia, torsional deformities) through appropriate osteotomies 1.

In post-TKA patients with patellar complications, recognize that internal malrotation of femoral and/or tibial components is the most common cause of patellofemoral instability (occurring in 1-12% of cases), and the severity of complications is directly proportional to the degree of combined internal rotation 2. This requires CT assessment and potential revision surgery rather than soft-tissue procedures alone 2.

When performing tibial tubercle osteotomy in dysplastic patellofemoral joints, favor anteromedialization over pure medialization to avoid excessive medial compartment contact forces and subsequent chondral overload 7.