As the orthopaedic community continues to solve complex issues related to joint replacement, it has become apparent that deformity correction and component positioning are keys to long-term success. In terms of hip, knee, and shoulder arthroplasty, we have progressed throughout the last 50 years with improved functional outcomes and component longevity. Elbow arthroplasty development has lagged somewhat because indications for that procedure are much less common.
Meanwhile, total ankle arthroplasty (TAA) experienced a short-lived decade of enthusiasm in the late 1970s and early 1980s before it became apparent that improved component designs and surgical techniques were needed. Progress with TAA stalled until the late 1990s, but TAA has now become more predictable, and several successful designs are available with reasonable revision rates demonstrated during 10-plus years of follow-up. As with all arthroplasties, component alignment in TAA is critical, and we have therefore assumed that significant preoperative frontal plane deformity is a contraindication for this procedure.
However, in the December 18, 2019 issue of The Journal, Lee et al. challenge that assumption with midterm follow-up data on 146 TAAs that suggest patients with frontal plane deformities >20° should not necessarily be disqualified from having this procedure. In this study, prior to surgery, 107 ankles had moderate frontal plane deformity (5° to <15° of varus or valgus) and 41 ankles had severe deformity (>20° to 35° of varus or valgus). The authors found no difference between these groups in terms of functional outcomes, complications, or implant survival at a mean follow-up of 6 years. Lee et al. conclude that frontal malalignment >20° in patients with end-stage ankle osteoarthritis may not be a contraindication to proceeding with TAA. However, the authors emphasize that concomitant realignment procedures at the time of index arthroplasty (including ligament releases and corrective osteotomies) were much more common in the severe group.
These findings need confirmation from other groups and with longer-term follow-up so that data from lower-volume surgeons can be analyzed and later complications can be investigated. Still, it just may be that ankle arthroplasty is not as finicky as we have been thinking.
Marc Swiontkowski, MD
Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz Specialty Update summaries.
This month, Mark T. Dahl, MD, co-author of the August 21, 2019 “What’s New in Limb Lengthening and Deformity Correction,” selected the five most clinically compelling findings from among the 40 noteworthy studies summarized in the article.
–Authors of a retrospective study of 119 patients with Crawford type-II congenital pseudarthrosis of the tibia found a 69% union rate at maturity. They did not identify specific factors influencing rates of union or refracture, however.1
–The models created with this technology can help surgeons preoperatively assess specific anatomical geometries. Corona et al.2 used 3-D-printed titanium truss cages, along with the Masquelet technique, to treat massive infected posttraumatic defects.
Growth Prediction in Limb Lengthening
–A comparative evaluation of the predictive accuracy of 4 methods to correctly time epiphysiodesis in 77 patients found the multiplier method to be the least accurate. In a separate study of 863 epiphysiodeses, authors reported a 7% complication rate.3 The most common complication was incomplete arrest that resulted in angular deformities; half of those cases required reoperation.
Congenital Limb Deficiencies
–Over 16 years, Finnish children born with lower-limb deficiencies had 6 times the number of hospital admissions and 10 times the number of days in hospital per child, compared with children born without a limb deficiency.4
- Shah H, Joseph B, Nair BVS, Kotian DB, Choi IH, Richards BS, Johnston C, Madhuri V, Dobbs MB, Dahl M. What factors influence union and refracture of congenital pseudarthrosis of the tibia? A multicenter long-term study. J Pediatr Orthop. 2018 Jul;38(6):e332-7.
- Corona PS, Vicente M, Tetsworth K, Glatt V. Preliminary results using patient-specific 3D printed models to improve preoperative planning for correction of post-traumatic tibial deformities with circular frames. Injury. 2018 Sep;49(Suppl 2):S51-9.
- Makarov MR, Dunn SH, Singer DE, Rathjen KE, Ramo BA, Chukwunyerenwa CK, Birch JG. Complications associated with epiphysiodesis for management of leg length discrepancy. J Pediatr Orthop. 2018 Aug;38(7):370-4.
- Syvänen J, Helenius I, Koskimies-Virta E, Ritvanen A, Hurme S, Nietosvaara Y. Hospital admissions and surgical treatment of children with lower-limb deficiency in Finland. Scand J Surg. 2018 Nov 19:1457496918812233. [Epub ahead of print]
The article, “Guiding Femoral Rotational Growth in an Animal Model” by Arami, et al. is an intriguing variation on the common applications of guided growth in pediatric patients. Implants that bridge the physis to inhibit growth in a given anatomic location are widely used to correct angular deformity or leg-length differences in the growing child and to decrease the need for a more invasive corrective osteotomy.
At present, correction of rotational deformity in the pediatric femur or tibia requires a derotational osteotomy and commonly six weeks of casting postoperatively. This study in rabbits demonstrates the ability of implants to alter the rotational profile in the growing femur by bridging the physis in an oblique orientation, rather than in a vertical orientation used for angular deformity correction.
The authors have elegantly demonstrated histologically the swirling or bending appearance of the physeal columns in treated femora, while controls maintained the normal linear columnar appearance of the physis. This interesting and unique animal study lays the foundation for consideration of using oblique placement of physeal-bridging implants to guide rotational growth in skeletally immature patients, without the need for osteotomy.