Cemented technique for total knee revision stems has been used widely. Fully cemented short metaphyseal engaging stems (30 to 70 mm) and longer, narrower stems, which are not canal fitting, are an option to decrease the micromotion in the wide cancellous bone area (Figure 2). When cementing stems in revision surgeries, intramedullary cement restrictors should be placed in tibial and femoral canals. The canals should be pressurized and filled in a retrograde manner before stem insertion. Moreover, the cement should be placed on the undersurface of the base femoral and tibial implant, at the stem-coupler junction, and along the cleansed and dried bony cuts.
Radiograph showing fully cemented stemmed rTKA. A, AP view. B, Lateral view. rTKA = revision total knee arthroplasty.
Gililland et al reviewed 49 revisions with cemented stem at 10 years follow-up. A 4% risk of re-revision was shown. None of the patients had subsidence or migration of the prosthesis. Knee Society Scores (KSSs) were improved significantly from preoperative value (mean of 52 points). The success rate of the cemented stems with aseptic failure as an end point was 92% for the femoral implant and 94% for the tibial implant.
Kim et al reported the results of cemented technique in 97 patients (114 knees) who underwent rTKA. The mean Hospital for Special Surgery knee score and mean Knee Society knee and functional scores were 31, 35, and 16 points before the operation and 83, 90, and 64 points at the time of the final follow-up, respectively. The complication rate was 9%. Kaplan-Meier survivorship analysis, with revision or radiographic failure as the end point, revealed that the 10-year rate of implants survival was 96% (95% confidence interval, 94% to 100%).
Baggio et al analyzed 27 patients older than 75 years retrospectively. With an average age of their participants of 82.6 ± 4.4 years and a follow-up of 43 ± 14.4 months, they did not find any mechanical failure of the implants. The functional average score was 115 ± 32 in the total KSS, of which 77 ± 17.5 points were in the KSS knee and 42 ± 24 in the KSS function. Radiologically, 18 patients presented radiolucent lines, but only three needed follow-ups using the modified Knee Society radiographic scoring system. Their results revealed that cemented stems are a good method for fixation in the rTKA in people older than 75 years with acceptable medium-term clinical results.
Fehring et al reviewed 113 rTKAs with 202 metaphyseal engaging stems. Of the 202 stems, 107 were cemented metaphyseal stems. Using a modified Knee Society radiographic scoring system, 100 (93%) of the 107 implants with cemented stems were considered stable, 7 (7%) were categorized as possibly loose requiring close follow-up, and none were loose after 57 months of follow-up. They urged caution in using noncemented metaphyseal engaging stems in rTKA.
Lachiewicz et al retrospectively reviewed 54 patients (58 knees) with fixation of the revision tibial implant with a 30-mm cemented stem extension. No loosening of any tibial implant was observed, and no re-revision was performed. There were no tibial radiolucent lines in 33 knees (57%). Seventy-three tibial radiolucent lines were seen in 25 knees (43%). These were seen on either the 6-week or 6-month postoperative radiograph and were not progressive. They found the 30-mm cemented stem extension provides adequate fixation for the tibial implant in rTKA, even in knees with metaphyseal defects reconstructed with tantalum cones and in knees with varus–valgus constrained polyethylene liners required for stability. Table 3 summarizes the studies of cemented tibial implants in rTKA.
Proponents of cemented stems believe that this method allows more freedom for AP and medial-lateral placement of the tibial baseplate and femoral implants (Table 1). In this way, the surgeon can fit the femoral prosthesis in the coronal plane more accurately and are able to manage flexion gap precisely. The risk of end-of-stem pain is lower with this technique. Shorter cemented stems can be easily used in those patients with previous trauma and diaphyseal deformity or those with the ipsilateral implant. Short, cemented stems may be considered the method of choice for individuals with dysplasia or inflammatory arthropathies who are not suitable for longer diaphyseal engaging stems.
Disadvantages of fully cemented stems are greater bone loss when removing these stems and reduced references for proper alignment of the prosthesis due to bone defects in epiphyseal–metaphyseal part of tibia and femur (Table 1).[15,24] Cemented implants have a larger cement mantle compared with hybrid fixation, which may require extended surgical time and result in greater bone loss than noncemented stems during revision, thereby cause more damage to the bone.[15,24] Edwards et al showed that cemented stems were significantly more likely to have radiographic loosening compared with noncemented stems (4.9% versus 1.6%, P = 0.02). The reamed diaphysis was a poor surface for cement interdigitation, leading to higher rates of radiolucency (32% versus 17%, P = 0.006).
J Am Acad Orthop Surg. 2022;30(9):e703-e713. © 2022 American Academy of Orthopaedic Surgeons