Another option is valgus tibial resection, which maintains native ligament balance at the cost of excessive valgus alignment. In the low-demand patient, a condylar constrained implant provides a means of correcting the malalignment with knee stability.8,13,17 The increased restraint produces greater forces at the implant–bone interface and may risk early loosening.
The case presented here represents a unique situation of failed bilateral high tibial osteotomies with excessive valgus malalignment. In a similar situation, Papagelopoulos and colleagues21 suggested correcting fracture deformities before or at time of knee arthroplasty. Yoshina and colleagues22 reported using a stemmed tibial component with TKA in treating nonunion of a high tibial osteotomy. As mentioned, Katz and colleagues5 and Neyret and colleagues7 suggested preoperative correction of the osteotomy in cases of severe malalignment. Others have suggested combining recorrection osteotomy and knee arthroplasty in either consecutive operations or a single operation.23-26 Wolff and colleagues27 and Uchinou and colleagues28 described recorrection osteotomy performed concurrent with TKA. The present article is the first to report a case involving concurrent bilateral recorrection osteotomy and TKA.
In one setting, the recorrection osteotomy is performed after the bony cuts are made for the TKA. The initial tibial plateau resection is performed in valgus at the same degree of malalignment as the osteotomy. This allows the plane of the tibial resection to parallel the floor once the recorrection is finished. With use of a tibial stem crossing the osteotomy site and a derotation plate, adequate fixation of the osteotomy is obtained. The recorrection osteotomy prevents the ligaments from overlengthening, allows the native ligament balance of the knee, and preserves the PCL—which lets the surgeon obtain ligament balance for the TKA throughout the arc of motion, avoiding midstance instabilities and achieving knee alignment rotationally and in the coronal and sagittal planes.
The TKA used in the present case was a PCL-retaining design. Both posterior-stabilized and PCL-retaining designs are reasonable options for use in combination with recorrection osteotomy. A stemmed tibial component is needed to cross the osteotomy site. In our patient’s case, use of a PCL-retaining design was based on surgeon preference and experience.
Patella infera has been noted as a problem in studies on converting high tibial osteotomy to TKA.9,12,29 A postulated cause is scarring of the infrapatellar tendon after high tibial osteotomy. In addition, a higher incidence of lateral retinacular release has been identified.9-11 Patella infera did not occur in either knee in the present case, and lateral release was not required.
Our patient’s lateral radiographs (Figures 4A, 4B) showed persistence of the osteotomy plane anterior to the tibia. The osteotomy healed posteriorly but not completely anteriorly. This raises the issue of risk for nonunion when recorrection osteotomy is performed with TKA. Use of a stemmed tibial implant with a derotation plate provides the benefit of intramedullary fixation for the recorrection osteotomy. If the recorrection osteotomy were performed in a separate setting before TKA, plate fixation would be the primary fixation option. Should nonunion occur at the recorrection osteotomy site, revision of the tibial plateau with a new stemmed implant would be required in combination with plate fixation. Madelaine and colleagues30 reported on a series of 15 severe varus knees treated with both osteotomy and TKA. Two nonunions occurred. Fixation was a staple in one case and a cement wedge in the other. Risk for nonunion may be reduced with the combination of stemmed tibial implant and internal fixation with a derotation plate. Protective weight-bearing is recommended for the first 6 postoperative weeks.
Conclusion
Ligament imbalances produced by high tibial osteotomy and exacerbated by conversion to TKA are difficult to address. In this report, we have described successful single-stage high tibial osteotomy recorrection and TKA performed bilaterally in separate settings. With use of a stemmed tibial component and a derotation plate, solid fixation was obtained with an excellent clinical outcome. The malalignment was corrected while ligament balance was maintained for a PCL-retaining TKA design.