Does the gap balance technique really elevate the joint line in total knee arthroplasty? A single-center, randomized...

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Total knee arthroplasty (TKA) aims to restore joint function and alignment.
• Accurate joint line (JL) restoration is crucial for optimal TKA outcomes.
• Gap balancing (GB) and measured resection (MR) are two common TKA techniques with differing approaches to achieving JL restoration.

Purpose of the Study:

• To compare the joint line (JL) measurements between gap balancing (GB) and measured resection (MR) techniques in total knee arthroplasty (TKA).
• To evaluate radiographic measurements from both the femoral and tibial sides to assess JL restoration accuracy.
• To determine the correlation between surgical release and JL measurements in TKA.

Main Methods:

• A randomized study included 107 patients undergoing TKA, divided into GB (n=54) and MR (n=53) groups.
• Radiographic measurements of adductor tubercle joint line (ATJL) and tibial tubercle joint line (TTJL) were performed.
• Clinical outcomes including range of motion, WOMAC, and KSS scores were assessed.

Main Results:

• Mean follow-up and operation times were comparable between GB and MR groups.
• The adductor tubercle joint line (ATJL) measurements were similar between the two techniques.
• The tibial tubercle joint line (TTJL) measurements were significantly different (p=0.01), with higher elevation in the GB group.
• A significant correlation was found between TTJL and the degree of surgical release (r=0.731, p<0.001).

Conclusions:

• While ATJL measurements are similar, TTJL measurements indicate a potential for higher JL elevation with the GB technique, possibly due to the degree of release.
• Radiographic JL assessment from both tibial and femoral sides may offer a more accurate evaluation in TKA.
• Measuring JL from the femoral side is recommended for a more precise assessment in TKA.