Clinical Trial: The Unstable Kneecap - the Impact of Anatomy on Function

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional

Official Title: Surgery for Patellofemoral Instability, is There Normal Gait

Brief Summary:

The principal objective of the study is to find out which everyday activities make the kneecap unstable in people with patellofemoral instability.

Analysing how a patient with an unstable kneecap walks will help us to determine if surgery is successful in these patients by seeing if better scores on patient questionnaires are found in patients following surgery and whether these patients also have a better pattern of walking.

The investigators aim to use cameras and pressure pads to see how patients walk before and after surgery and see how this compares to patient scores on the questionnaires.

If the investigators find that patients walk better after surgery they can justify that surgery is worthwhile for the patient and cost effective for the NHS.

Detailed Summary:

Recruitment strategy:

Patients referred to a specialist patellofemoral clinic with an unstable kneecap(s) will be approached by the student and asked whether they would be interested in participating in the study (study group). Participants will be considered eligible for the study group if they have had two or more episodes of kneecap dislocation or many episodes of instability with at least one of the following: a feeling that the kneecap will dislocate with pressure, tenderness along the inner side of the knee and/or abnormal movement or position of the kneecap.

They will be given a Patient Information Sheet (PIS) and be given time during the clinic to ask questions about the study. During this first appointment as per routine current clinical practice they will have an X-ray of their knee and fill in standard questionnaires to score their knee function and pain (Norwich Patellofemoral Instability score, Kujala score, PainDetect score, catastrophising score). The patient's knees will also be examined by the consultant and a record made of the clinical findings. As per routine practice, a magnetic resonance imaging (MRI) scan of both knees will be organised for 4 weeks after the original appointment and measurements of knee shape recorded. A total of 32 patients will be invited to join the study to assess the movement of the kneecap in patients with kneecap instability.

A group of normal knees (control group) will be studied to compare the findings from students aged 18 to 50 years at St George's University of London allowing both age and gender to be matched to the study group . Students with no previous history of knee problems will be eligible to join the control group.

Inclusion criteria for both groups includes age 18
Sponsor: St George's, University of London

Current Primary Outcome: Number of participants with abnormal gait who have patellar instability [ Time Frame: Before surgery ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

• Number of patients with normal gait 6 months after surgery to correct patellar instability [ Time Frame: 6 months ]
  Graphical measurement of raw kinematic data to include joint moments at ankle, knee and hip comparing patients after surgery to correct patellar instability to normal controls
• Number of patients with normal ground reaction force 6 months after surgery to correct patellar instability [ Time Frame: 6 months ]
  Measurement of ground reaction force of patients after surgery to correct patellar instability compared to normal controls
• Number of patients with a change in patellar tracking at the time of surgery to correct patellar instability [ Time Frame: during surgery ]
  Graphical presentation of patellar movement in three dimensions measured intra-operatively during corrective surgery
• Number of patients with a change in patellar pressure at the time of surgery to correct patellar instability [ Time Frame: during surgery ]
  Graphical presentation of patellar pressure in three dimensions measured intra-operatively during corrective surgery
• Number of patients who have an abnormal EMG compared to normal controls [ Time Frame: before surgery ]
  Electromyographic (EMG) output in graphical form comparing patients with patellar instability to normal controls
• Number of patients with a change in EMG 6 months after surgery to correct patellar instability [ Time Frame: 6 months ]
  Electromyographic (EMG) output in graphical form comparing patients before and after surgery

Original Secondary Outcome:

• Number of patients with normal gait after surgery to correct patellar instability [ Time Frame: 6 months ]
  Graphical measurement of raw kinematic data to include joint moments at ankle, knee and hip comparing patients after surgery to correct patellar instability to normal controls
• Number of patients with normal ground reaction force after surgery to correct patellar instability [ Time Frame: 6 months ]
  Measurement of ground reaction force of patients after surgery to correct patellar instability compared to normal controls
• Number of patients with a change in patellar tracking after surgery to correct patellar instability [ Time Frame: during surgery ]
  Graphical presentation of patellar movement in three dimensions
• Number of patients with a change in patellar pressure after surgery to correct patellar instability [ Time Frame: during surgery ]
  Graphical presentation of patellar pressure in three dimensions
• Number of patients who have an abnormal EMG compared to normal controls [ Time Frame: before surgery ]
  Electromyographic (EMG) output in graphical form comparing patients with patellar instability to normal controls
• Number of patients with a change in EMG after surgery to correct patellar instability [ Time Frame: 6 months ]
  Electromyographic (EMG) output in graphical form comparing patients before and after surgery

Information By: St George's, University of London

Dates:
Date Received: September 30, 2015
Date Started: December 2015
Date Completion: December 2018
Last Updated: October 31, 2016
Last Verified: October 2016