2015 ISAKOS Biennial Congress ePoster #2003

Flexion Laxity in Isolated Posterior Cruciate Ligament Injured Knee Correlate with the Result of Conservative Treatment

Yasukazu Yonetani, MD, PhD, Hirakata, Osaka JAPAN
Kousuke Sakata, MD, Itami JAPAN
Takashi Kanamoto, MD, PhD, Sakai, Osaka JAPAN
Yoshio Matsui, MD, PhD, Osaka JAPAN
Yoshinari Tanaka, MD, PhD, Ibaraki, Osaka JAPAN
Shuji Horibe, MD, PhD, Habikino, Osaka JAPAN

Osaka Rousai Hospital, Sakai, Osaka, JAPAN

FDA Status Not Applicable

Summary: Flexion gap, rather than posterior sagging, might influence the outcome of conservative treatment of PCL injury.




Conservative treatment for posterior cruciate ligament (PCL) injury has been reported to succeed in 70% of athletes . However, posterior laxity (PL) has no correlation with the results of the conservative treatment and prognostic factor of the conservative treatment remains unclear. Considering the sagittal alignment of PCL at 90° flexion and increasing of flexion gap (FG) after resection of PCL in total knee replacement, it is hypothesized that PCL might play a role not only in posterior stabilization but also in maintaining the FG. Previously, plain radiographs with the x-ray beam projected along the femoral shaft (axial radiography), used to evaluate FG, revealed that FG increased in isolated PCL injured knee. Therefore, the purpose of this study is to investigate whether FG and PL influence onresults of the conservative treatment of PCL injury.

Patient and Method:The radiographs of 37 patients (29 men, 8 women; mean age, 33 years; 13–69 years) with isolated PCL injuries between 2007 and 2013 were reviewed retrospectively. 7 patients was Grade 1 (PL less than 5mm), 20 patients was Grade 2 (5 to 10mm), and 10 patients was Grade 3 (more than 10mm). All patients were treated conservatively after the injury for more than six months. 21 patients achieved the excellent relief of symptoms and returned to sports (C group). 16 patients underwent PCL reconstruction owing to their symptoms related to knee instability in sports and/or daily living activities, (S group).

The axial radiography and lateral gravity sag view were obtained to measure PL and FG. Differences between the injured and contralateral normal knees were calculated. The correlation between the increment of the FG and PL were analyzed using Spearman’s rank correlation coefficient test. The comparison in each two laxity between two groups was analyzed using the Wilcoxon signed-rank test.


The mean of PL and FG was 7.0±3.1, 0.7±0.5 mm in Cgroup, and 10.4±3.4, 1.8±1.0 mm in S group. The both of PL and FG in C group were significantly smaller than those of S group (p<0.01). Moreover, positive correlation between PL and FG were obtained (RS=0.49). All 7 Grade I patients belonged to C group showed that FG was less than 1mm. Eight of 22 Grade ? patients were received PCL reconstruction and their FG showed more than 1mm. In contrast, 8 of 10 patients in PCL grade ? were treated operatively and showed no correlation with FG amount.


The surgical indication for chronic isolated PCL GradeI/II injury patients remains controversial because of good clinical outcome after conservative treatment. This study showed the good correlation between PL and FG, and both laxities in patients who underwent PCL reconstruction were significantly greater than those in patients who had symptom relief after conservative treatment. Considering FG affects outcome of conservative treatment, it could be a factor of indication of surgical treatment for isolated PCL injury in addition to PL.