**6.2 Role of patellofemoral alignment**

Similar to unloading osteotomy and cartilage surgery for tibiofemoral joint articular cartilage lesions with malalignment, patellofemoral joint chondral pathology in the setting of patellofemoral malalignment also warrants unloading via tibial tubercle osteotomy when combined with cartilage surgery. In the setting of lateral patellar or trochlear defects, unloading via osteotomy should include either medialization (Elmslie-Trillat) or

Management of Knee Articular Cartilage Injuries 121

Fig. 12. Management of symptomatic chondral defect of medial or lateral femoral condyle. Concurrent issues, such as meniscal deficiency and coronal plane malalignment, need to be addressed, either simultaneously or sequentially in a staged manner. The most important defect-specific parameter is size (area in cm2), dictating treatment choice. MAT (meniscus allograft transplantation), HTO (high tibial osteotomy), OWHTO (opening wedge HTO), CWHTO (closing wedge HTO), DFO (distal femoral osteotomy), OAT (osteochondral autograft), ACI (autologous chondrocyte implantation), OC (osteochondral) allograft. Yellow (cartilage restorative technique); Red (cartilage reparative technique); Purple

(cartilage palliative technique).

**8. Articular cartilage defect management algorithm** 

anteromedialization (Fulkerson). The degree of medialization needed may be estimated with pre-operative measurement of the TT-TG (tibial tubercle-trochlear groove) distance. Nevertheless, the surgeon must be cognizant during the pre-operative workup and the operation itself to assure that no medial patellar or trochlear pathology exists if planning to unload the lateral patellofemoral compartments, as this will increase stress on degenerative cartilage(Kuroda, Kambic et al. 2001). Distal patellar cartilage pathology may warrant anteromedialization to allow the patella to enter the trochlea in earlier degrees of flexion and unload the distal cartilage pathology(Colvin and West 2008). In the presence of lateral patellar tilt, a lateral retinacular release may be indicated(Arendt 2009). Medial patellofemoral ligament (MPFL) insufficiency may warrant reconstruction(Arendt 2009).

#### **6.2.1 Outcomes**

The clinical outcomes following patellofemoral realignment osteotomy have demonstrated success with the proper indications. In patients with lateral and distal patellar defects, anteromedialization led to 100% patient satisfaction with 87% good to excellent results, while patients with medial, proximal, or diffuse defects had only 43% good to excellent results(Pidoriano, Weinstein et al. 1997). Excellent short- and mid-term outcomes have been demonstrated when distal patellofemoral realignment has been combined with ACI(Bentley, Biant et al. 2003; Minas and Bryant 2005; Henderson and Lavigne 2006; Farr 2007; Gigante, Enea et al. 2009; Gobbi, Kon et al. 2009).
