# An Unexpected Complication of Hip Arthroplasty: Knee Dislocation

## TL;DR

An 82-year-old patient with hip fracture and osteoporosis experienced unexpected knee dislocation during surgery, requiring a knee prosthesis.

## Contribution

Highlights the risk of knee dislocation during hip surgery in patients with advanced osteoarthritis.

## Key findings

- Knee dislocation occurred during hip reduction in a patient with degenerative arthritis.
- A hinged knee prosthesis was needed nine days post-surgery due to persistent instability.
- Overtraction during hip reduction should be avoided in patients with advanced osteoarthritic knees.

## Abstract

An increasing number of patients with hip fracture have been seen with osteoporosis associated with osteoarthritis. Although knee dislocation is related to high-energy trauma, low-grade injuries can also lead to knee dislocation which is defined as “ultra-low velocity dislocation.” The case reported here is of an 82-year-old patient who presented with a left intertrochanteric hip fracture. Partial arthroplasty was planned because of osteoporosis. In the course of surgery, degenerative arthritic knee was dislocated during the hip reduction maneuver with the application of long traction. The neurovascular examination was intact, but the knee was grossly unstable and was dislocated even in a brace; thus a hinged knee prosthesis was applied nine days after surgery. The patient was mobilized with crutches after the knee prosthesis but exercise tolerance was diminished. In conclusion, it should be emphasized that overtraction must be avoided during the hip reduction maneuver in patients with advanced osteoarthritic knee.