Posterior Dislocation of the Hinge-Post Extension in a Rotating Hinge Total Knee Prosthesis

Givenchy Manzano,Ran Schwarzkopf

doi:10.1155/2013/756538

Givenchy Manzano, Ran Schwarzkopf

Open Access

https://doi.org/10.1155/2013/756538

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Abstract

The rotating hinge knee prosthesis is a popular intervention in patients lacking stability with highly constrained total knee arthroplasty. Despite improvements in design, nonmechanical and mechanical complications continue to be a problem. Dislocation of the hinge has been widely described, mainly due to the component fracture. Few reports describe isolated dislocation of the rotating stem. We report a case of isolated disengagement of the rotating hinge mechanism, due to severe flexion gap imbalance, leading to subsequent posterior dislocation of the hinge and anterior knee dislocation, in a patient with a history of multiple total knee arthroplasty revisions. This case suggests the importance of the soft tissue balancing, the adequate patellar tracking, and use of a long cylindrical, minimally tapered rotating stem in hinge arthroplasty to minimize hinge dislocation.

Highlights

The rate of revision total knee arthroplasty in the United States has been steadily increasing over the years [1]
Modern rotating hinge implants evolved in an attempt to avoid aseptic loosening and component fractures seen in the first-generation fixed hinge knee prostheses by allowing motion in more than one plane to decrease the high stresses on the articulation and at the bone cement interface [2]
This is commonly seen in knees with deficient ligamentous structures secondary to tumor resection, trauma, multiple knee revisions, extensor mechanism dysfunction, distal femoral nonunion, or massive distal femoral bone loss [5, 6, 10, 15, 16]

Summary

Introduction

The rate of revision total knee arthroplasty in the United States has been steadily increasing over the years [1]. Modern rotating hinge implants evolved in an attempt to avoid aseptic loosening and component fractures seen in the first-generation fixed hinge knee prostheses by allowing motion in more than one plane to decrease the high stresses on the articulation and at the bone cement interface [2]. The effects of these improvements are reflected in reports of rotating hinge arthroplasty survival rates of 89.2%–96.1% after 6 to 20 years [3, 4]. Case Reports in Orthopedics a case of atraumatic disengagement of the rotating stem due to opening of the flexion gap, leading to subsequent posterior dislocation of the hinge and anterior knee dislocation in a patient with a history of multiple total knee arthroplasty revisions

Case Study

Discussion