Tibial Tubercle Osteotomy vs the Extensile Medial Parapatellar Approach in Revision Total Knee Arthroplasty: Is Tibial Tubercle Osteotomy a Harmful Approach?

Background: As the frequency of total knee arthroplasty (TKA) is increasing, long-termfollow-up of patients has become essential, and the frequency of revision total knee arthroplasty (R-TKA) due to the occurrence of various complications has also increased. There is controversy regarding which approach has minimal complications and an adequate visual field in R-TKA. Therefore, we compared the clinical and radiological results between the extensile medial parapatellar (EMP) approach and tibial tubercle osteotomy (TTO) for R-TKA. Methods: Between March 1, 2000, and December 31, 2015, we compared 35 patients who underwent the EMP approach and 31 who underwent the TTO approach for R-TKA. In this study, the preoperative range of motion (ROM) was an important criterion for the choice of approach in R-TKA. The EMP approach was applied to patients with a ROM above 60 degrees. The TTO approach was applied to patients with knee flexion limited to 0 degrees-30 degrees. We clinically assessed knee ROM, Knee Society scores, and Hospital for Special Surgery scores at the time of the last follow-up. We radiographically measured femorotibial alignment and patellar height. We also examined the complication rates. The average length of the TTO was 1.0 x 2.5 cm x 10 cm. We used 3 or more 3.5-mm half-threaded screws. Results: The mean postoperative ROM of the knee joint at the time of the last follow-up was 103 degrees (flexion contracture 5 degrees and further flexion 108 degrees) in the group that underwent the EMP approach and 101 degrees (flexion contracture 4 degrees and further flexion 109 degrees) in the group that underwent the TTO approach. The mean Knee Society scores were 86 (71-96) and 85 (72-94), and the mean Hospital for Special Surgery scores were 82 (70-93) and 83 (68-92) for the 2 groups, respectively, with no statistically significant difference. The mean femorotibial angles were 0.6 degrees (+/- 3.3 degrees) and 0.1 degrees (+/- 2.9 degrees), and the mean Insall-Salvati ratios were 1.0 (+/- 0.34) and 0.8 (+/- 0.14), respectively, with no statistically significant difference. The group that underwent TTO achieved bone union at an average of 11.8 weeks after surgery. In the group that underwent the EMP approach, 2 patients had extensor lag of more than 10 degrees. In the group that underwent TTO, 2 subjects had skin necrosis at the operative site. Conclusion: The clinical and radiological outcomes were similar in the 2 groups after R-TKA. To increase the ROM and obtain adequate exposure, TTO is also considered a useful surgical approach. However, complications related to TTO should be minimized. (C) 2019 Elsevier Inc. All rights reserved.