# Does previous total hip arthroplasty affect the outcomes of total knee arthroplasty? A one- and five-year follow-up registry study in a monocentric hospital

## TL;DR

This study found that patients who had hip and knee replacements managed their daily lives and pain similarly to those with only a knee replacement, despite initial differences in walking distance.

## Contribution

The study provides new insights into the long-term outcomes of patients who underwent both hip and knee arthroplasty compared to those with only knee arthroplasty.

## Key findings

- THA/TKA patients walked shorter distances than TKA patients one year post-surgery.
- No significant differences in overall function or pain were found between TKA and THA/TKA patients after five years.
- Both groups showed similar improvements in function over time.

## Abstract

Osteoarthritis in the lower extremities becomes more common as people age. In addition to conservative treatments, hip or knee arthroplasty is often needed. The aim of this study was to evaluate total knee arthroplasty (later TKA) in patients, comparing those who had previously undergone THA (later THA/TKA), with those who had not undergone such procedure. Pain, walking ability and functional capacity were assessed.

Patients who underwent primary TKA between 1987 and 2017 at a single orthopaedic hospital was included in this study. The patients participated in clinical preoperative and postoperative examinations by an orthopaedic surgeon after one- and five- years. The final study group consisted of 418 patients who had undergone 502 knee arthroplasties. Of these 502 TKA cases, 462 had not undergone previous THA and 40 had undergone previous THA. To evaluate the patients’ physical function and walking ability, a structure form for knee arthroplasty based on the Hungerford score was used. The registry data from the Finnish National Institute of Health and Welfare was used. The data included TKA revision(s) and mortality events.

At the baseline and after one- and five- years primary TKA, no statistical differences were found in the total Hungerford score between TKA patients and THA/TKA patients. In both groups, the total score increased per surgery year. However, when analysing the relationship between the year of operation and the total score, no statistical differences were found between the groups (TKA and THA/TKA) at five years (p = 0.61). The only statistical difference found between the groups was in walking distance points after one year; THA/TKA patients (mean 83 [SD 17]) could walk remarkably shorter distances than TKA patients (91 [14]) one year after arthroplasty (p < 0.001).

In conclusion, walking distance improved more rapidly in TKA patients than in THA/TKA patients. However, patients who underwent more than one arthroplasty in their lower extremities managed their lives, activities, and pain almost as well as those who underwent only one knee arthroplasty.