Can a large osteochondral fragment from the medial patellar facet be fixed arthroscopically with trans‑osseous polydiaxanone (PDS) sutures in an 18‑year‑old male with a first‑time patellar dislocation and MPFL disruption?

Arthroscopic Fixation of Large Medial Patellar Osteochondral Fragments with Trans-Osseous PDS Sutures

Yes, arthroscopic fixation of large medial patellar facet osteochondral fragments with trans-osseous PDS sutures is technically feasible and has been successfully performed, though open approaches remain more commonly described for large fragments requiring stable compression. 1

Technical Feasibility and Approach

Arthroscopic Technique

• Arthroscopic reduction and fixation of patellar osteochondral fractures following dislocation has been successfully performed using manipulation of the patella through a loosened medial retinaculum, allowing adequate visualization and access for anterograde fixation. 1
• The arthroscopic approach requires adequate fragment size and minimal comminution to achieve stable fixation. 2

Trans-Osseous Suture Configuration

• Trans-osseous suture fixation using absorbable materials provides several advantages: it accommodates smaller fragments than screw fixation, avoids hardware prominence and cartilage abrasion, eliminates need for hardware removal, and prevents foreign body reactions associated with metallic implants. 2
• The "parachute" technique creates transosseous tunnels in a confluent fashion at the fragment margins, passing sutures through established tunnels to provide evenly distributed pressure without penetrating the fragment itself, which is particularly effective for large osteochondral fragments. 3
• A crossing suture technique using 4 holes in a rectangular pattern perpendicular to the patella's anteroposterior surface, with sutures looped around the osteochondral fragment, provides secure compression and allows early mobilization. 2

Critical Decision Points for Technique Selection

When Arthroscopic Approach is Appropriate

• Fragment must be accessible through standard arthroscopic portals with adequate visualization after medial retinacular manipulation. 1
• Minimal comminution is present, allowing stable suture fixation. 2
• Surgeon has expertise in arthroscopic suture passing techniques and trans-osseous tunnel creation.

When Open Approach is Preferred

• Large fragments requiring rigid compression fixation may benefit from open reduction with bioabsorbable compression screws, which provides straightforward compression across fragments and excellent stability for early range of motion. 4
• The open approach allows direct visualization for anatomic reduction and assessment of fragment viability, particularly important in delayed presentations where fibrocartilage growth may have begun. 5
• Concomitant procedures are planned, such as medial patellofemoral ligament (MPFL) reconstruction or tibial tubercle osteotomy for persistent patellar maltracking. 5

Important Considerations for Your 18-Year-Old Patient

Timing of Intervention

• Early fixation of displaced osteochondral fragments is paramount to maintaining articular cartilage viability and patellar congruency. 4
• Even delayed presentations up to 8 weeks post-injury can achieve successful union with appropriate fixation and concurrent realignment procedures if needed. 5

Addressing Concurrent MPFL Disruption

• After achieving stable osteochondral fragment fixation, assess patellar tracking—if lateral subluxation persists, MPFL reconstruction and/or lateral release should be performed to protect the fracture fixation and prevent recurrent instability. 5
• This combined approach addresses both the osteochondral injury and the underlying instability mechanism that caused the initial dislocation.

Common Pitfalls to Avoid

• Inadequate fragment compression: PDS sutures must be tensioned appropriately to achieve compression; loose fixation will result in nonunion or fibrocartilage fill rather than hyaline cartilage healing. 2
• Ignoring patellar maltracking: Fixing the osteochondral fragment without addressing persistent lateral patellar instability risks re-injury and fixation failure. 5
• Attempting arthroscopic fixation beyond technical capability: If adequate visualization or reduction cannot be achieved arthroscopically, convert to open approach rather than accepting suboptimal fixation. 4
• Using metallic implants for superficial fragments: Screws or K-wires risk cartilage abrasion, hardware prominence, and require subsequent removal; absorbable sutures avoid these complications. 2