**4.7 Return to Play**

Few studies have reported on return to play after patellar stabilization in patients with patellofemoral instability [142–145].

Schneider and associates [142] performed a systematic review and meta-analysis to evaluate the outcomes of isolated MPFL reconstruction for the treatment of recurrent patellofemoral instability. Fourteen articles met the inclusion criteria and were included in this review. The mean age of the patients was 24 years. The mean postoperative Tegner score was 5.7 and the pooled estimated mean postoperative Kujala score was 86. Eighty-four per cent of the patients returned to sports after surgery. The pooled total risk of recurrent instability after surgery was 1%, with a positive apprehension sign risk of 4% and a reoperation risk of 3%. The authors concluded that a high percentage of young patients return to sports after isolated MPFL reconstruction for chronic patellar instability, with short-term results demonstrating a low incidence of recurrent instability, postoperative apprehension, and reoperations.

Sherman and colleagues [143] evaluated the existing literature regarding return to play (RTP) and return to prior performance (RPP) following patellar stabilization surgery. These authors found that there is a lack of validation and universal adoption of standardized RTP guidelines. The best available studies to date would suggest high RTP rates (84–100%), average RPP rates (33–77%), and a highly variable timeframe (3 to 12 months) for return to sport. Sherman et al. [143] concluded that the best available data on RTP and RPP following patellofemoral instability is based on lower quality of evidence studies, expert opinion, and published societal guidelines.

Manjunath et al. [144] performed a systematic review to determine both the rate and timing of return to play after MPFL reconstruction, and the rate of further patellar instability. Their review found 27 studies including 1278 patients meeting the inclusion criteria. The majority of patients were women (58%), and the total group had a mean age of 22 years. The mean follow-up was 39 months. The overall rate of return to play was 85% (with 68% returning to the same level of play). The average time to return to play was 7 months postoperatively. The rate of recurrent instability events following reconstruction was 5%.

Platt et al. [145] undertook a systematic review and meta-analysis to evaluate return to sport after MPFL reconstruction for patellar instability. Twenty-three articles met the inclusion criteria after full-text review. A total of 930 patients were analyzed, including 786 athletes. The overall mean age of the patients was 21 years. Women represented 61% of all patients. The mean follow-up was 3 years (range, 0.8 to 8.5 years). The return to sport rate was 93%. Patients returned to or surpassed their preoperative level of activity in 71% of cases. An osteotomy was performed in 11% of the athletes. Return to sport did not differ significantly in

patients undergoing MPFL reconstruction without osteotomy versus those receiving additional osteotomy. Patients returned to sport at a mean of 6.7 months (range, 3 to 6 months) postoperatively. The overall complication rate was 9%. The most common complication was recurrence of instability.

We emphasize that the treating surgeon should counsel their patients preoperatively regarding their expectations and outcomes of treatment. Based on abovementioned studies, a high rate of return to sport after MPFL reconstruction surgery is expected. In our experience, most athletes return to play around 6 to 8 months after undergoing MPFL reconstruction.

#### **4.8 Complications of MPFL Reconstruction**

Postoperative complications following MPFL reconstruction include subcutaneous hematoma, wound infection, dehiscence, seroma after graft harvest, persistent pain, knee stiffness, flexion contracture, recurrent instability, patellar fracture, and deep vein thrombosis. The cause of recurrent patellar instability may be technically inadequate MPFL reconstruction or failure to address other concomitant pathology. Persistent pain may be caused by the over-constrained MPFL, unaddressed chondral defect in the patellofemoral compartment, or patellar fracture.

Shah and associates [146] performed a systematic review to determine the rate of complications associated with MPFL reconstruction. A total of 164 complications occurred in 629 knees (26%). These complications included wound infection, knee pain, restriction of knee flexion, recurrent patellar instability, and patellar fracture. Twenty-six patients returned to the operating room for additional procedures.

Parikh and colleagues [147] have reported the early complications (<3 years) of MPFL reconstruction in young patients. A total of 179 knees underwent MPFL reconstruction during the study period. There were 38 complications (16%) in 29 knees. The major complications included recurrent lateral patellar instability, knee motion stiffness with flexion deficits, patellar fractures, and patellofemoral arthrosis/pain. In their series, 18 of 38 (47%) complications were secondary to technical factors and were considered preventable. Female gender and bilateral MPFL reconstructions were risk factors associated with postoperative complications. Patients should be counseled preoperatively on the risk of potential complications that may occur after MPFL reconstruction.

Common fixation techniques for MPFL reconstruction at the patella include transosseous bone tunnels [148, 149], suture anchors [122, 150, 151], and interference screws [152–154]. It has been reported that the patellar tunnel techniques present a higher risk of postoperative patellar fractures, particularly for those that pass completely through the patella [146, 147, 155–159]. In view of the high risk of patellar fracture with the use of transosseous tunnel technique, the suture anchor fixation was introduced [154, 160]. Suture anchors provide a stable fixation and are gaining increasing popularity. Good to excellent results have been reported with the use of suture anchors for fixation of the tendon graft in MPFL reconstruction [122, 150].

#### **4.9 Authors' Preferred Treatment of MPFL Reconstruction**

In order to eliminate the risk of patellar fracture (that may occur using the patellar tunnel technique), the senior author of this paper (AJS), prefer to use suture anchors to fix the tendon graft to the medial border of the patella. Kurowicki et al. [130] have reported the Patella Footprint Technique of MPFL reconstruction. In our *Patellofemoral Instability DOI: http://dx.doi.org/10.5772/intechopen.99562*

opinion, this surgical technique provides a safe, reliable and reproducible method of restoring patellofemoral stability. The Patella Footprint Technique minimizes the stress risers in the patella by using suture anchor fixation that creates a ligamentous footprint instead of tendon healing into a bony socket in the patella.
