Recurring intraprosthetic dislocation of rotating-hinge total knee prosthesis. Effect of implant design on intrinsic stability

Abstract

During total knee replacement, hinged total knee implants are used in cases where ligament balancing cannot be achieved with less-constrained implants. The case of a patient who experienced two episodes of intraprosthetic dislocation of his rotating-hinge total knee prosthesis is described. There are very few reports of this type of dislocation with these implants. The implant's design, particularly of the hinge, plays an important role in stability. The balance between the flexion and extension spaces is very important even when using a hinged total knee implant. The role of the extensor mechanism in anteroposterior stability is reviewed, along with simple ways to augment it.

Potential Instability and Malfunction of Knee Joints with Vastus Medialis Impairment after Total Knee Arthroplasty

“…Therefore, posterior dislocation of the tibia may be induced if VM impairment occurs after TKA. This is consistent with clinical reports showing that posterior dislocations of the tibia have been reported in patients with VM impairment, particularly quadriceps impairment, following TKA in clinical practice [9,19,20].…”

“…Furthermore, Christensen et al reported that the TKA-related quadriceps impairment produced an asymmetry extension moment, which limited the physical function of the knee joint [3]. Sharkey et al, Cavaignac et al, and Lee et al have reported that extensor impairment caused by quadriceps impairment led to a greater risk of posterior instability in knee joints that had undergone TKA [9,19,20]. Furthermore, Cottino et al reported that patients with quadriceps impairment had a high risk of hyperextension after TKA because they tended to lock the knee during the extension phase of gait to compensate for a weak extensor mechanism and to avoid instability.…”

Failure of the Yoke With a Rotating-Hinge Total Knee Arthroplasty

“…Radiographs of S-ROM rotating-hinge prosthesis showing femoral loosening and dissociation of the femoral and tibial components due to yoke failure. Several factors can lead to yoke failure, including mechanical yoke failure and disengagement due to instability from surrounding soft tissues, integrity of the extensor mechanism and ligaments, imbalanced flexion-extension gaps, recurvatum, and incorrect joint line positioning 11,16 . There are very few published reports of yoke failure.…”

Complications and failures of non-tumoral hinged total knee arthroplasty in primary and aseptic revision surgery: A review of 290 cases

“…Mechanical failure of TKA implants is now rare because of improvements in their design and the use of hinged rotatory models [15,32,43,49,51,52]. The extensor mechanism continues to be a cause of complications, with patellar instability being more common than extensor mechanism rupture.…”

“…Pietrzak et al [4] showed that the TKA revision surgery rate increased by 6.5 times between 2010 and 2015 for the same team. For these surgical revisions, hinged TKA implants often appear to be the best solution especially when a patient presents with instability or significant bone loss [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Furthermore, hinged TKA implants have a place in primary surgery with the main indications being major laxity in the collateral ligaments, large deformity, chronic inflammatory arthropathy, neurological conditions and traumatic and post-traumatic lesions [17,20,21].…”