What Is the Role for Patelloplasty With Gullwing Osteotomy in Revision TKA?

Abstract

Background: Management of the patella in revision total knee arthroplasty (TKA) is challenging as a result of the deficient or unusable bone stock for patellar resurfacing that is frequently encountered. Options proposed in this setting include various patelloplasty procedures, patellectomy, and special patellar components. We sought to better define the role and results of one patelloplasty procedure, the gullwing osteotomy, used in revision TKA.

Questions/purposes: (1) How much improvement in the outcome measures of range of motion and Knee Society scores was seen after revision TKA with a gullwing osteotomy? (2) What are the radiographic results of this osteotomy as judged by patellar healing and patellar tracking? (3) What complications are associated with the gullwing osteotomy in revision TKA?

Methods: Between December 2003 and July 2012, we used a gullwing osteotomy on patients undergoing revision TKA (n = 238) in which the patellar remnant was avascular or less than 12 mm thick. This uncommon procedure was used in 17 of 115 (15%) of the patellae revised during this time. We performed manual chart reviews on all patients to collect preoperative and postoperative range of motion and Knee Society scores as well as radiographic review at last followup to assess patellar healing and tracking.

Results: In patients with at least 2 years of followup, the preoperative range of motion was a median -7.5° of extension (interquartile range [IQR], -15°-0°) and 90° of flexion (IQR, 90°-100°). Postoperative extension improved to 0° (IQR, 0°-0°; p = 0.015). With the numbers available, median flexion arc did not change at last followup (110°; IQR, 95°-120°; p = 0.674). The Knee Society score improved from a combined (clinical + functional) mean of 86 (95% confidence interval [CI], 56-116) preoperatively to 142 (95% CI, 121-163; p < 0.001) postoperatively. Radiographically, 12 of 13 patients demonstrated healing of the osteotomy with osseous union and one patient healed with a fibrous union. Nine of the 10 patients with at least 2 years of followup had a centrally tracking gullwing osteotomized patella at last followup. One patient, with just over 3 years of followup, exhibited lateral subluxation without evidence of fracture. Three of the 10 patients with greater than 2 years of followup developed recurrent infections. One patient had avascular necrosis with fragmentation of the patella at 4 months postoperatively.

Conclusions: Patellar bone stock is often compromised in revision TKA, leaving the surgeon with very few options for reconstruction. Using this technique, we found acceptable function, no aseptic rerevisions for patellofemoral complications, nine of 10 of patellae tracking within the trochlear groove, and radiographic healing of the majority of the osteotomies. The gullwing osteotomy may be considered an option in these difficult revisions, but further studies with more complete followup are needed.

Level of evidence: Level IV, therapeutic study.

Fig. 1

This flow diagram demonstrates the number of revision TKAs performed during this time period, the number of gullwing osteotomies, and ultimately the number of patients included in the series.

Fig. 2

In this sunrise view, the patella is seen preoperatively, 6 weeks after the index gullwing osteotomy, and 3 years after the index procedure.

Fig. 3

These images demonstrate lateral tracking (lateral subluxation) of the patella both before and 6 weeks after with a healed patella after gullwing osteotomy.

Fig. 4

A fibrous union of the patella is seen in this image 6 years after the index gullwing osteotomy was performed.

Fig. 5A–D

This series of images portrays what appears to be a healthier patella preoperatively (A) and immediately after the index procedure (B). However, avascular necrosis of the patella is seen at both the 6-week followup (C) and further at the (D) 4-month followup.