**4.4 Use of Autograft versus Allograft for MPFL Reconstruction**

Kumar et al. [138] completed a retrospective chart review on patients younger than 18 years of age who underwent MPFL reconstruction for recurrent instability after failed nonoperative management. The patients were divided into autograft or allograft hamstring cohorts for comparison. Primary outcome measures were return to normal activity, incidence of redislocation/subluxation, pain, stiffness, Kujala scores, and other complications. After criteria were applied, there were 59 adolescents (38 girls and 21 boys; mean ± SD age of 15.2 ± 1.7 years). Allograft was used in 36 patients and the autograft in 23. The patients were reviewed at a mean follow-up of 4.1 ± 1.9 years (allograft, 3.3 ± 1.1 years; autograft, 5.7 ± 2.1 years;

P ≤ 0.001). The authors identified no significant differences in return to activity, pain score changes, and incidences of failure between patients undergoing MPFL reconstruction with allograft versus autograft. Although teenagers with surviving autograft MPFL reconstruction reported statistically higher Kujala scores, the mean score difference of 5 points was not clinically significant. It appears that using allograft tendon instead of autograft tissue for MPFL reconstruction in this teenage population does not adversely affect the long-term outcomes.

The choice of autograft or allograft for MPFL reconstruction is based on surgeon and/or patient preference. A thorough preoperative counseling should be undertaken, and advantages and disadvantages of each graft source should be discussed with the patient before choosing the tendon graft for MPFL reconstruction.

#### **4.5 Single-Bundle or Double-Bundle MPFL Reconstruction?**

Singhal et al. [139] carried out a meta-analysis of studies reporting outcomes of MPFL reconstruction using hamstring tendon autograft in a double-bundle configuration and patellar fixation via mediolateral patellar tunnels. The primary outcome examined was the postoperative Kujala score. The authors identified 320 MPFL reconstructions in nine relevant articles. The combined mean postoperative Kujala score was 92 using a fixed effects model and 89 using random effect modeling. The reported rate of complications with MPFL reconstruction was 12.5% (40 of 320), with stiffness of the knee being the most common. The authors concluded that high-quality evidence in assessing double-bundle MPFL reconstruction is lacking. The current literature consists of a mixture of prospective and retrospective case series. High-quality, prospective randomized controlled trials are needed before definitive conclusions can be drawn regarding the superiority of one form of surgical technique over the other.

Kang et al. [140] performed a systematic review of the single-bundle (SB) and double-bundle (DB) MPFL reconstruction procedures using the hamstring tendon autografts, and compared the clinical outcomes including the Kujala score, postoperative apprehension, recurrent subluxation or dislocation, and complications. Thirty-one articles were included, involving 1063 patients (1116 knees). Two hundred and forty-four patients (254 knees) underwent SB reconstruction, whereas 819 patients (862 knees) underwent DB reconstruction. The pooled mean values of Kujala score improvement were similar in both groups. The SB group had a significantly greater rate of postoperative apprehension (8%) than the DB group (4%). There were no significant differences between the SB and DB groups in the rates of recurrent subluxation or dislocation and complications. The authors concluded that the DB procedure for isolated MPFL reconstruction demonstrates similar outcomes as compared to the SB technique regarding improvement of knee function, recurrent subluxation or dislocation, and complications. The SB technique may have a greater risk of postoperative apprehension, whereas the DB technique may cause more stiffness.

#### **4.6 Outcomes of MPFL Reconstruction in Skeletally Immature Patients**

Shamrock et al. [141] performed a systematic review and meta-analysis of the literature to evaluate the outcomes and complications of MPFL reconstruction in skeletally immature patients. Seven studies that entailed 132 MPFL reconstructions (126 patients) met the inclusion criteria. There were 73 females (58% of the cohort) and the mean age was 13 years (range, 6 to 17 years). Mean postoperative follow-up was 4.8 years (range, 1.4 to 10 years). Autograft was used for all reconstructions, with gracilis tendon (61%) being the most common. Methods of femoral fixation

#### *Patellofemoral Instability DOI: http://dx.doi.org/10.5772/intechopen.99562*

included interference screw (39%), suture anchor (39%), and soft tissue pulley around the medial collateral ligament or adductor tendon (22%). Pooled Kujala scores improved from 59 to 85 after MPFL reconstruction. The total reported complication rate was 25% and included 5 redislocations (4%) and 15 subluxation events (11%). No cases of premature physeal closure were noted. Neither autograft choice nor the method of femoral fixation influenced recurrent instability or overall complication rates. These findings suggest that MPFL reconstruction in skeletally immature patients is a viable and reasonable treatment option, with significant improvement in patient-reported outcomes and redislocation event rates of less than 5% at nearly 5-year follow-up. Further high-quality research should be undertaken to determine optimal surgical technique and graft options.
