What is the treatment for a fractured bone spur on the patella?

Treatment of Fractured Bone Spur on the Patella

For a fractured bone spur (osteophyte) on the patella, surgical excision of the fragment is the treatment of choice when symptomatic, as conservative management rarely resolves mechanical symptoms or pain from loose fragments. 1

Initial Assessment

Evaluate for the following critical findings that determine treatment urgency:

• Extensor mechanism integrity: Assess ability to perform straight leg raise against gravity—this is the single most important determinant of treatment approach 1
• Fragment displacement: Determine if the bone spur fragment is displaced or causing mechanical symptoms (locking, catching) 1
• Associated injuries: Rule out underlying patella fracture, as bone spurs can fracture at their base while the main patella remains intact 2
• Soft tissue status: Check for open wounds, skin compromise, or signs of infection 1

Treatment Algorithm

Non-Operative Management (Limited Role)

Conservative treatment is appropriate only for:

• Non-displaced fragments with intact extensor mechanism 1
• Minimal or no mechanical symptoms 1

Protocol includes:

• Rigid immobilization with knee brace or cast in extension for 4-6 weeks 1
• Pain management with NSAIDs or acetaminophen 1
• Early quadriceps isometric exercises to prevent atrophy 1

Critical caveat: Risk of subsequent displacement is 30-50% with non-operative management, requiring close radiographic surveillance at 1-2 week intervals initially 1

Surgical Management (Preferred for Most Cases)

Indications for surgery:

• Displaced bone spur fragments causing mechanical symptoms 1
• Persistent pain despite conservative trial 3
• Any disruption of extensor mechanism 1
• Loose intra-articular fragments 2

Surgical options:

1. Fragment excision (most common for bone spurs):

   • Remove the fractured osteophyte fragment arthroscopically or through mini-open approach 3
   • Smooth any remaining irregular bone surfaces 2
   • This is preferred over fixation for small peripheral fragments 3

2. Open reduction and internal fixation (if fragment is large):

   • Reserved for substantial fragments that contribute to patellar articular surface 4
   • Modified tension band wiring or cannulated screws with tension band 4, 5

3. Partial patellectomy (salvage option):

   • Only if fragment involves significant portion of patella with comminution 4
   • Preserve as much patella as possible to maintain quadriceps strength 6

Post-Treatment Rehabilitation

Early mobilization is critical to prevent knee joint capsule contractures and cartilage degeneration 1:

• Week 0-2: Gentle passive range of motion exercises, quadriceps sets 1
• Week 2-6: Progressive active range of motion, straight leg raises 1
• Week 6-12: Strengthening exercises, gradual return to activities 1
• Long-term: Continue knee exercises indefinitely to maintain function 1

Imaging Follow-Up

• Radiographs at 3 weeks post-treatment to confirm healing or fragment removal 7
• Additional imaging at time of immobilization removal (if conservative) 7
• CT may be needed if complex intra-articular involvement suspected 8

Common Pitfalls to Avoid

• Delayed diagnosis: Bone spur fractures are often missed on initial radiographs; obtain axial (sunrise) views of patella 2
• Inadequate immobilization: Failure to maintain extension can lead to extensor mechanism disruption 1
• Overtightening splints: Can compromise circulation—monitor neurovascular status 8
• Premature weight-bearing: Can displace fragments or disrupt healing 1
• Neglecting rehabilitation: Leads to permanent stiffness and quadriceps atrophy 1

Complications to Monitor

• Hardware irritation (if fixation used) requiring later removal 9
• Posttraumatic arthritis from articular surface irregularity 9
• Arthrofibrosis from inadequate early motion 9
• Extensor mechanism weakness (10-15% loss of strength expected even with optimal treatment) 6