Trust-, Local Health Board- and unit-level activity and outcomes

Outlier units for 90-day mortality and revision rates for the period 2003 to 2015

The observed numbers of revisions of hip and knee replacements for each hospital were compared to the numbers expected given the unit’s case-mix in respect of age, gender and reason for primary surgery. Hospitals with a much higher than expected revision rate for hip and knee replacement have been identified. These hospitals had a revision rate that was above the upper of the 99.8% control limits (these limits approximate to +/-3 standard deviations). We would expect 0.2% (i.e. one in 500) to lie outside the control limits by chance, with approximately half of these (one in 1,000) to be above the upper limit.

When examined over the life of the registry, a total of 30 hospitals reported higher than expected rates of revision for knee replacement and 44 hospitals had higher than expected rates of revision for hip surgery. However, revisions taken only from the last five years of the registry showed only ten hospitals reporting higher than expected rates for knees, and four for hips.

The 90-day mortality for hip and knee replacement was calculated for all hospitals by plotting standardised mortality ratios for each hospital against the expected number of deaths. One hospital (closed in 2013) had a higher than expected mortality rate for knee replacement while none were identified for hip replacement.

Note: The case mix for mortality includes age, gender and ASA grade. Trauma cases have been excluded from both the hip and knee mortality analyses together with hips implanted for failed hemi- arthroplasty or for metastatic cancer (the latter only from November 2014 when recording of this latter reason began). Also, where both left and right side joints were implanted on the same day, only one side was included in the analysis.
 
Note: Any units identified as potential outliers in Part Four have been notified. All units are provided with an Annual Clinical Report and additionally have access to an online NJR Management Feedback system.

Important note about the outlier hospitals listed below
In previous annual reports, the NJR has reported outlying hospitals based on all cases submitted to the NJR since 1 April 2003. To reflect changes in hospital practices and component use, the NJR now also reports outlying hospitals based on the last five years of data (21 February 2011 to 20 February 2016 inclusive, the latter date being when the dataset was cut). This five year cut of data excludes from the analysis the majority of withdrawn outlier implants, and metal on metal total hip replacements, and thus better represents contemporary practice.

Outlier for Hip mortality rates since 2003 (note1):
None identified

Outlier for Knee mortality rates since 2003 (note1):
Redwood Diagnostic Treatment Centre [closed in 2013]

Outliers for Hip revision rates, all linked primaries from 2003 (note1):
Nevill Hall Hospital
The Royal London Hospital
Sussex Orthopaedic NHS Treatment Centre
Llandough Hospital
Prince Charles Hospital
Queen Elizabeth The Queen Mother Hospital
Basingstoke and North Hampshire Hospital
Homerton University Hospital
Maidstone District General Hospital [closed in 2011]
Medway Maritime Hospital
Northampton General Hospital (Acute)
University Hospital Of Hartlepool
University Hospital Of North Tees
North Tyneside General Hospital
Royal Cornwall Hospital (Treliske)
St Michael's Hospital
Salisbury District Hospital
Musgrove Park Hospital
Rotherham District General Hospital
Pilgrim Hospital
Hospital Of St Cross
University Hospital (Coventry)
St Albans City Hospital
Watford General Hospital
York Hospital
BMI Gisburne Park Hospital (Lancashire)
BMI Sarum Road Hospital (Hampshire)
BMI The Somerfield Hospital (Kent)
Shepton Mallet Treatment Centre (Somerset)
Nuffield Health Brighton Hospital (East Sussex)
Nuffield Health Haywards Heath Hospital (West Sussex)
Nuffield Health Tees Hospital (Cleveland)
Nuffield Health Wessex Hospital (Hampshire)
Nuffield Health York Hospital (North Yorkshire)
Ashtead Hospital (Surrey)
New Hall Hospital (Wiltshire)
North Downs Hospital (Surrey)
Clifton Park Hospital (North Yorkshire)
Dunedin Hospital (Berkshire)
Spire Alexandra Hospital (Kent)
Spire Cardiff Hospital (Glamorgan)
Spire Gatwick Park Hospital (Surrey)
Spire Harpenden Hospital (Hertfordshire)
Spire Tunbridge Wells Hospital (Kent)

Outliers for Hip revision rates, all linked primaries from 2011 (note 2):
Wrexham Maelor Hospital
Salisbury District Hospital
St Richard's Hospital
Watford General Hospital

Outliers for Knee revision rates, all linked primaries from 2003 (note 1):
Bradford Royal Infirmary 
Llandough Hospital 
Conquest Hospital
Good Hope Hospital
Homerton University Hospital 
Withybush General Hospital 
Charing Cross Hospital
James Paget University Hospital 
Southmead Hospital 
Southampton General Hospital 
South Tyneside District Hospital 
Cannock Chase Hospital 
County Hospital 
Louth Grantham and District Hospital 
University College Hospital Hospital of St Cross
St Richard's Hospital St Albans City Hospital
Weston Treatment Centre [closed in 2007] 
BMI Goring Hall Hospital (West Sussex) 
BMI The Meriden Hospital (West Midlands)
North East London NHS Treatment Centre (Essex) 
Shepton Mallet Treatment Centre (Somerset) 
Southampton NHS Treatment Centre  (Hampshire)
King Edward VII Hospital Sister Agnes (Greater London) 
New Hall Hospital (Wiltshire)
Horton NHS Treatment Centre (Oxfordshire) 
Spire Alexandra Hospital (Kent)
Spire Clare Park Hospital (Surrey)
Spire Southampton Hospital (Hampshire)

Outliers for Knee revision rates, all linked primaries from 2011 (note 2):
Ashford Hospital
Charing Cross Hospital
County Hospital Louth
University College Hospital
St Richard's Hospital
BMI The London Independent Hospital (Greater London)
North East London NHS Treatment Centre (Essex)
Southampton NHS Treatment Centre (Hampshire)
King Edward VII Hospital Sister Agnes (Greater London)
Spire Southampton Hospital (Hampshire)

Note:1: 1 April 2003 to 20 February 2016 inclusive. 
Note 2: 21 February 2011 to 20 February 2016 inclusive.

Implant- and unit-level activity and outcomes 2015

Part Four of the annual report gives performance and data entry quality indicators for Trusts, Local Health Boards (many of whom comprise more than one hospital) and independent (private) providers in England, Wales, Northern Ireland and the Isle of Man for the 2015 calendar year. Outcomes analysis after hip and knee replacement surgery is also provided for the period 2003 to 2015. This section now also provides data for implant outliers since 2003 and further information on notification and last usage date.

Clinical activity

Overall in 2015, 151 NHS Trusts and Local Health Boards (comprising 247 separate hospitals) and 177 independent hospitals were open and eligible to report patient procedures to the NJR. Of these units, only eleven did not submit any data.

The proportion of all hip and knee joint replacements entered in to the NJR against those carried out (compliance) is only available by NHS Trust and Local Health Board. No data on this is currently available from private providers and figures would also exclude units in Northern Ireland and the Isle of Man as compliance is not available.

At the time of publication, it has not been possible to produce compliance figures for the financial year 1 April 2015 to 31 March 2016 due to the unavailability of data from the Hospital Episodes Statistics (HES) service.

Of those hospitals submitting data, the proportion of patients who gave consent for their details to be entered into the NJR (consent) were:

NHS hospitals
•    50% of NHS hospitals achieved a consent rate of greater than 95%
•    38% achieved a consent rate of 80% to 95% and
•    12% recorded a consent rate of less than 80%

Independent hospitals
•    68% of independent hospitals achieved a consent rate greater than 95%
•    24% achieved a consent rate of 80% to 95% and
•    8% recorded a consent rate of less than 80%

Similarly, the proportion of entries in which there is significant data to enable the patient to be linked to an NHS number (‘linkability’) are listed below:

NHS hospitals
•    88% achieved a proportion of patients with a linkable NHS number greater than 95%
•    11% achieved a proportion of 80% to 95% and
•    1% recorded a proportion of linkable records of less than 80%

Independent hospitals
•    66% achieved a proportion of patients with a linkable NHS number greater than 95%
•    28% achieved a proportion of 80% to 95% and
•    6% recorded a proportion of linkable records of less than 80%

Note: Independent hospitals might be expected to have lower linkability rates than NHS hospitals, as a proportion of their patients may come from abroad and not have an NHS number. Linkability figures are not currently available for Northern Ireland or the Isle of Man.

Trust-, Local Health Board- and unit-level activity and outcomes 2015

Part Four of the annual report gives performance and data entry quality indicators for Trusts, Local Health Boards (many of whom comprise more than one hospital) and independent (private) providers in England, Wales, Northern Ireland and the Isle of Man for the 2015 calendar year. Outcomes analysis after hip and knee replacement surgery is also provided for the period 2003 to 2015.

This section now also provides data for implant outliers since 2003 and further information on notification and last usage date.