Published online Mar 18, 2020. doi: 10.5312/wjo.v11.i3.184
Peer-review started: September 28, 2019
First decision: December 24, 2019
Revised: December 24, 2019
Accepted: January 19, 2020
Article in press: January 19, 2020
Published online: March 18, 2020
Patellar clunk syndrome (PCS) is a postoperative complication following total knee arthroplasty that clinically presents as anterior knee pain that is particularly painful when going from full flexion to extension. The pathoanatomy of PCS involves the accumulation of scar tissue along the undersurface of the quadriceps tendon, proximal to the superior pole of the patella. The diagnosis of PCS can often be made clinically, but radiographic adjuncts such as ultrasound and magnetic resonance imaging have been used with success. Unfortunately, there is no current literature that evaluates multiple metrics of the native knee and prosthesis to determine what metric is most responsible for the development of PCS.
The main topics of the current study are (1) characterizing and analyzing metrics implicated in the pathogenesis of PCS; and (2) defining contemporary management, treatment, and preventative algorithms for PCS. The current study aims to elucidate how various prosthesis and geometries of native knee can cause PCS or prevent it from occurring, which are poorly summarized and defined in the literature currently.
The main objective of the current study is to evaluate current evidence and characterize a reasonable etiology for the development of PCS. A secondary objective of the current study is to better understand the various treatment and preventative heuristics implemented to manage PCS.
A systematic review of clinical research studies from PubMed, Google Scholar, and Cochrane was conducted, as these databases were felt to be representative of peer-reviewed scholarly work and well encompassed literature surrounding PCS. Each study was analyzed and results were compiled in designated tables with a predetermined list of metrics and its corresponding incidence of PCS. Details regarding prevention, treatment, and management were also extracted at this time.
A total of 30 articles were identified through the primary search, with an additional 3 included from reference lists of the primary search. Results indicate that prosthesis design was the most frequently cited metric as contributory towards PCS. The prosthesis design is often a combination of multiple metrics and, therefore, we conclude that the etiology of PCS is multifactorial. A reduced intercondylar box ratio and box width has been consistently shown to reduce PCS.
Prosthesis design is the main metric associated with the etiology of PCS, though because the prosthesis design incorporates several other metrics included in our analysis, the etiology of PCS is multifactorial. Later prosthesis designs that incorporate a reduced intercondylar box ratio and box width can reduce development of PCS. Preventative strategies involve using later generations of prosthesis especially those that incorporate a reduced intercondylar box ratio.
Overall, this study was able to confirm the etiology of PCS as well as provide insight into treatment methods to prevent this postoperative complication. Nevertheless, future studies should aim to isolate individual metrics of prosthesis design to more specifically determine which metric is most responsible for the development of PCS. Higher level randomized control trials should also be conducted to generate additional evidence to improve knee maneuverability and function post-total knee arthroplasty.