Lateral Patellar Facetectomy Reduces the Incidence of Anterior Knee Pain in Patellar Resurfaced Total Knee Arthroplasty

Relationship between cement penetration and incidence of a radiolucent line around the tibia 2 years after total knee arthroplasty: A retrospective study

OBJECTIVES

Cement penetration (CP) plays a key role in implant stability for cemented total knee arthroplasty (TKA) and the radiolucent line (RLL) >2mm is a preliminary sign for loosening of components. However, the direct relationship between CP and the frequency of RLL >2 mm is unclear and the best cutoff value for CP to prevent RLL >2 mm also remain unclear. This study aimed to investigate this relationship between CP and RLL and to determine the clinical cutoff value for tibial CP in patients 2 years after TKA.

METHODS

This retrospective study investigated 157 knees from 123 patients with osteoarthritis who underwent cemented TKA. The CP and RLL immediately after TKA and the RLL 2 years after TKA were measured for the medial, lateral, anterior, and posterior tibial baseplate zones. Receiver operating characteristic (ROC) curves were constructed to determine the best cutoff values for CP.

RESULTS

RLL >2 mm was not observed just after TKA. RLL >2 mm was observed in any tibial baseplate zone in 22 knees from 20 patients (RLL+ group) and was not observed in the remaining (RLL- group) 2 years after TKA. Mean CP for all zones was significantly higher in the RLL- group (2.5 ± 1.1 mm) than in the RLL+ group (1.7 ± 0.6 mm; P<0.001). RLL >2 mm was seen in 21 knees in the medial zone, 9 knees in the lateral zone, 8 knees in the anterior zone, and 3 knees in the posterior zone. CP values with RLL >2 mm were significantly lower than those without the RLL at the medial, anterior, and posterior tibial baseplate zones. The best cutoff values from the ROC curve of CP in each zone were between 1.1 mm and 2.1 mm.

CONCLUSIONS

The depth of the CP directly affects the incidence of RLL >2 mm. The best cutoff value for tibial CP to prevent RLL >2 mm is 2.1 mm.

Pressurized carbon dioxide lavage reduces the incidence of a radiolucent line around the tibial component two years after total knee arthroplasty

Introduction

In cemented total knee arthroplasty (TKA), pressurized carbon dioxide (CO₂) lavage prior to cement fixation can eliminate debris at the bone-cement interface and is considered effective for increasing cement penetration and preventing aseptic loosening. Regarding the risk of a preliminary diagnosis of implant loosening, a radiolucent line (RLL) is a valuable sign. The purpose of this study was to compare the incidence of a tibial RLL at 2 years after TKA with and without pressurized CO₂ lavage.

Methods

This is a retrospective study. One hundred knees from 98 patients were enrolled in this study. TKA was performed without pressurized CO₂ lavage (CO₂− group) for the first 47 knees, and with pressurized CO₂ lavage (CO₂+ group) for the next 53 knees. The depth of cement penetration was measured just after surgery, and the incidence of tibial RLL > 2 mm at 2 years after TKA was determined.

Results

Significant differences between groups were not seen regarding pre- and postoperative clinical factors. The depth of cement penetration in each area was significantly higher in the CO₂+ group. The frequency of knees with RLL > 2 mm was significantly lower in the CO₂+ group than in the CO₂− group (p < 0.001).

Conclusions

Pressurized CO₂ lavage improved cement penetration and decreased the incidence of tibial RLL > 2 mm at 2 years after TKA.