[Two kinds of lateral retinacular release for lateral patellar compression syndrome:a retrospective comparative study].

Objective: To compare the clinical effects of arthroscopic lateral retinacular proximal release and "L" type release for lateral patellar compression syndrome. Methods: Sixty four lateral patellar compression syndrome (LPCS) patients were recruited who had arthroscopic surgery during September 2004 to January 2019 at Department of Sports Medicine,Peking University Third Hospital by the same group of doctors and a retrospective comparative study was conducted accordingly. Among them,24 cases underwent the traditional proximal release of lateral patellar retinaculum (traditional group),including 7 males and 17 females with an age of (42.9±14.6)years(range:23 to 72 years); 40 cases were treated with novel lateral retinacular release of "L" type release revised based on the previous experiences (novel group), consisting of 12 males and 28 females with an age of (54.9±13.1) years (range:28 to 76 years).All the patients participated surveys for the visual analogue scale (VAS),Lysholm score and International Knee Documentation Committee (IKDC) knee function subjective evaluation before and after the operation. The comparison of scores within groups was performed by Wilcoxon test,and comparison between groups was performed by Mann-Whitney U test and Chi-square test. Multivariate analysis was used to evaluate the related factors affecting each score. Results: The follow-up durations of traditional group and novel group were (12.6±1.0) years (range:11.7 to 15.3 years) and (2.2±1.0)years(range:1.0 to 4.4 years) respectively. At the last follow-up,VAS(0(1.0)to 6.0(2.0), Z =-5.471, P <0.01),Lysholm score(98.0(10.0)to 48.0(40.0), Z =-5.511, P <0.01),and IKDC score(82.8(11.2)to 37.4(18.5), Z =-5.444, P <0.01) in novel group were statistically significantly improved,and the postoperative excellent rate of Lysholm score was 97.5% in general. There was no significant difference in the changes of the three scores ( P >0.05) between the traditional group and the novel group. However,20.8% (5/24)patients in the traditional group reported significant weakness of the knee extension after surgery,while no such complain was received in the novel group ( P <0.01).The results of univariate analysis showed that surgical method was a related factor affecting the changes of VAS before and after surgery ( P <0.05).The results of multivariate analysis showed that whether or not with osteoarthritis and operation type were independent factors affecting the changes of Lysholm and IKDC scores ( P <0.05). Conclusions: The long-term effect of arthroscopic lateral retinacular release for the treatment of LPCS is satisfactory. Compared with the traditional proximal release surgery,the "L" type release can effectively avoid the complication of significant weakness of the knee extension significantly.