Surgical Management of Patella Alta in Patellofemoral Instability: A Systematic Review and Meta-analysis

Abstract

Background: Proximal, distal, and combined proximal and distal procedures have been performed for patellofemoral instability in the presence of patella alta. No consensus exists regarding the accepted surgical management for this condition. Purpose: To pool the outcomes of surgical management for patellofemoral instability in the presence of patella alta and to determine whether the outcomes differ for different surgical techniques. Study Design: Systematic review; Level of evidence, 4. Methods: This systematic review was conducted using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All studies that reported surgical outcomes for patellofemoral instability in the presence of patella alta were included. The random-effects model was used to analyze pooled estimates of preoperative and postoperative differences for outcomes that were reported in ≥3 studies. If heterogeneity existed among the studies, further analysis was performed using random-effects meta-regression analysis, which allowed for the identification of moderators. Results: A total of 11 studies with 546 knees were included. The pooled relative risk (RR) of having no patellofemoral dislocation and no patellofemoral apprehension or subjective instability postoperatively was 51.80 (95% CI, 20.75-129.31) and 48.70 (95% CI, 17.22-137.71), respectively. The pooled weighted mean improvement (WMI) for the Kujala and Lysholm scores postoperatively was 31.98 (95% CI, 28.66-35.30) and 35.93 (95% CI, 30.12-41.74), respectively. The pooled WMI for patellar tilt angles postoperatively was 10.94 (95% CI, 7.87-14.01). These outcomes were homogeneous across all studies. The pooled WMI for Insall-Salvati ratio, Caton-Deschamps index, and tibial tubercle–trochlear groove distance postoperatively was 0.31 (95% CI, 0.17-0.45), 0.24 (95% CI, 0.12-0.36), and 6.77 (95% CI, 1.96-11.58), respectively. These outcomes were heterogeneous across the studies, with the presence of distal procedures being a significant moderator. The presence of distal procedures had a significantly higher unweighted RR of 38.07 (95% CI, 2.37-613.09) for major complications compared with proximal procedures alone, although the incidence of minor complications was comparable (unweighted RR, 1.25; 95% CI, 0.35-4.48). Conclusion: Surgical management for patellofemoral instability in the presence of patella alta consistently led to improvement in clinical and functional outcomes, regardless of the type of procedure performed. Distal procedures were better able to correct the patellar height and tibial tubercle–trochlear groove distance, although these procedures also posed a higher RR of subsequent surgery compared with proximal procedures alone.

Anatomo-radyographic study in individuals with and without medial patellofemoral ligament rupture

“…Patella alta is also a known risk factor for recurrent instability following isolated MPFL reconstruction [12]. There are studies in the literature examining patella instability reconstruction in individuals with patella alta [11][12][13][14]. Our study results support the literature that patella alta is an anatomical risk factor.…”

Patellar Tendon Imbrication for the Treatment of Patella Alta in Skeletally Immature Patients

“…Patellar instability is a common pathology among adolescent patients, and the anatomical predisposition of patella alta can further play a role in frequent subluxation and dislocation events. [1][2][3] While tibial tubercle osteotomy has been used successfully for the correction of patellar height, [9][10][11] it can cause damage to the open physes of skeletally immature patients. In light of these limitations, soft-tissue procedures are better suited to treat this patient population, and may avoid the complications associated with tibial tubercle osteotomy such as nonunion, fracture, or hardware irritation.…”

“…[6][7][8] Distalizing tibial tubercle osteotomy has served as an effective treatment for patients with patella alta and patellar instability. [9][10][11] However, this procedure is contraindicated in the skeletally immature patient population, as it could lead to growth arrest of the proximal tibial physes. Patellar tendon imbrication has been proposed as a soft-tissue alternative in skeletally immature patients with patellar instability.…”

Distalization of tibial tubercle osteotomy is not necessary for patients with recurrent patellar dislocation accompanied by patella alta and increased TT–TG distance

“…When the TT-TG distance is too wide, the lateral sagittal force on the patella increases, resulting in patellar dislocation [15]. When the patella is in a high position, the time when the patella enters the trochlear groove is delayed or the patella even is unable to enter the trochlear groove, which reduces the effect of the trochlear groove to limits the lateral translation of the patella and increases the risk of patellar dislocation [18][19][20]. Additionally, patella alta has been noted to be a risk factor for recurrent instability after they undergo conservative treatment or isolated MPFLR.…”