Posterior cruciate ligament resection in total knee arthroplasty

Abstract

Aims The aim of this study was to assess the effect of posterior cruciate ligament (PCL) resection on flexion-extension gaps, mediolateral soft-tissue laxity, fixed flexion deformity (FFD), and limb alignment during posterior-stabilized (PS) total knee arthroplasty (TKA). Patients and Methods This prospective study included 110 patients with symptomatic osteoarthritis of the knee undergoing primary robot-assisted PS TKA. All operations were performed by a single surgeon using a standard medial parapatellar approach. Optical motion capture technology with fixed femoral and tibial registration pins was used to assess gaps before and after PCL resection in extension and 90° knee flexion. Measurements were made after excision of the anterior cruciate ligament and prior to bone resection. There were 54 men (49.1%) and 56 women (50.9%) with a mean age of 68 years (sd 6.2) at the time of surgery. The mean preoperative hip-knee-ankle deformity was 4.1° varus (sd 3.4). Results PCL resection increased the mean flexion gap significantly more than the extension gap in the medial (2.4 mm (sd 1.5) vs 1.3 mm (sd 1.0); p < 0.001) and lateral (3.3 mm (sd 1.6) vs 1.2 mm (sd 0.9); p < 0.01) compartments. The mean gap differences after PCL resection created significant mediolateral laxity in flexion (gap difference: 1.1 mm (sd 2.5); p < 0.001) but not in extension (gap difference: 0.1 mm (sd 2.1); p = 0.51). PCL resection significantly improved the mean FFD (6.3° (sd 4.4) preoperatively vs 3.1° (sd 1.5) postoperatively; p < 0.001). There was a strong positive correlation between the preoperative FFD and change in FFD following PCL resection (Pearson’s correlation coefficient = 0.81; p < 0.001). PCL resection did not significantly affect limb alignment (mean change in alignment: 0.2° valgus (sd 1.2); p = 0.60). Conclusion PCL resection creates flexion-extension mismatch by increasing the flexion gap more than the extension gap. The increase in the lateral flexion gap is greater than the increase in the medial flexion gap, which creates mediolateral laxity in flexion. Improvements in FFD following PCL resection are dependent on the degree of deformity before PCL resection. Cite this article: Bone Joint J 2019;101-B:1230–1237

The Disproportionate Increase of the Intraoperative Flexion and Extension Gap Space after Posterior Cruciate Ligament Resection in Total Knee Arthroplasty

“…Kayani et al retained MCL integrity and used the open-chain method for measurement. The results showed that PCL resection increased the flexion gap by 1.1 cm [15], which agreed with our results.…”

“…We discovered that PCL resection increased the flexion gap, consistent with previous studies [15,16,19,[24][25][26]. Park et al found that PCL resection with simultaneous extensive MCL release during TKA obviously increased the mean flexion gap, by 3.95 mm [27].…”

“…However, evidence is inconsistent regarding whether PCL resection increases the flexion gap. Many studies have stated that PCL resection has no effect on the extension gap but increases the flexion gap by 1.1-1.9 mm [15,16]. Other studies have indicated that PCL resection does not affect the flexion gap in PS TKA or cause a flexion-extension gap mismatch [17][18][19], and that the flexion gap is affected only when PCL resection is combined with medial collateral ligament (MCL) release [20,21].…”

The Influence of Posterior Cruciate Ligament Resection on Tibiofemoral Joint Gap in Varus Osteoarthritic Knees

“…They showed the significant increase of the tibiofemoral joint gaps with the ACL and PCL resections; however, the difference of the tibiofemoral joint gaps changes was less than 1.3 mm in their study. Kayani et al 23 evaluated the effect of the PCL resection on the gaps after the ACL resection and prior to bone resection in PS-TKA patients. Their results showed that the PCL resection increased the flexion gap 2.4 mm and the extension gap 1.3 mm in the medial, and 3.3 mm in flexion and 1.2 mm in extension in the lateral compartments.…”

The current state of robotics in total knee arthroplasty

“… 58 Inadvertent PCL resection should be avoided as it creates gap-balancing mismatch by increasing the flexion gap more than the extension gap. 59 Given the importance of optimal gap balancing in reducing instability and minimizing wear, the soft tissue protection offered by semi-active systems via haptic feedback may therefore improve functional outcomes and survivorship in the long term.…”