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

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 past ten years of the registry, a total of 40 hospitals reported higher than expected rates of revision for knee replacement, and 25 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 15 hospitals reporting higher than expected rates for knees, and ten for hips.

The 90-day mortality rate for primary hip and knee replacement was calculated using the last five years of data for all hospitals by plotting standardised mortality ratios for each hospital against the expected number of deaths. No hospitals had higher than expected mortality rates for either hip or knee 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 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 here have been notified. All units are provided with an NJR Annual Clinical Report and additionally have access to the online NJR Management Feedback system.

Important note about the outlier hospitals listed

In earlier annual reports, the NJR 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 reports outlying hospitals based on the last ten years (15 February 2010 to 14 February 2020) and five years of data (15 February 2015 to 14 February 2020 inclusive, the latter date being when the dataset was cut). These cuts of data exclude the majority of withdrawn outlier implants and metal-on-metal total hip replacements from analysis, and thus better represent contemporary practice.

Outliers for Hip mortality rates since 2015²

None identified

Outliers for Knee mortality rates since 2015²

None identified

Outliers for Hip revision rates, all linked primaries from 2010¹

Ashtead Hospital (Surrey)
Basingstoke and North Hampshire Hospital
BMI Clementine Churchill Hospital (Middlesex)
BMI The Meriden Hospital (West Midlands)
Chesterfield Royal Hospital
Colchester General Hospital
Fitzwilliam Hospital (Cambridgeshire)
Hexham General Hospital
Homerton University Hospital
Milton Keynes Hospital
North Downs Hospital (Surrey)
North Tyneside General Hospital
Nuffield Orthopaedic Centre
Salisbury District Hospital
South Tyneside District Hospital
Southampton General Hospital
Spire Liverpool Hospital (Merseyside)
St Richard's Hospital
Sussex Orthopaedic NHS Treatment Centre
The Holly Private Hospital (Essex)
University Hospital (Coventry)
Wansbeck Hospital
Watford General Hospital
Weston General Hospital
Wrexham Maelor Hospital

Outliers for Hip revision rates, all linked primaries from 2015²

BMI The Meriden Hospital (West Midlands)
Fitzwilliam Hospital (Cambridgeshire)
Hexham General Hospital
Milton Keynes Hospital
North Tyneside General Hospital
Nuffield Health Cheltenham Hospital (Gloucestershire)
Salisbury District Hospital
Southampton General Hospital
Wansbeck Hospital
Weston General Hospital

Outliers for Knee revision rates, all linked primaries from 2010¹

Abergele Hospital
Ashford Hospital
BMI Bishops Wood Hospital (Middlesex)
BMI Goring Hall Hospital (West Sussex)
BMI The London Independent Hospital (Greater London)
BMI The Meriden Hospital (West Midlands)
Broadgreen Hospital
Charing Cross Hospital
County Hospital Louth
Diana Princess of Wales Hospital
Ealing Hospital
Guy's Hospital
Heatherwood Hospital
Hillingdon Hospital
Hinchingbrooke Hospital
Homerton University Hospital
Horton NHS Treatment Centre (Oxfordshire)
King Edward VII Hospital Sister Agnes (Greater London)
Mount Vernon Treatment Centre
Nevill Hall Hospital
Nottingham City Hospital
Nuffield Health Chichester Hospital (West Sussex)
Orthopaedics and Spine Specialist Hospital (Cambridgeshire)
Queen Elizabeth The Queen Mother Hospital
Riverside Treatment Centre
South Tyneside District Hospital
Southampton General Hospital
Southmead Hospital
Spire Hull and East Riding Hospital (East Yorkshire)
Spire Southampton Hospital (Hampshire)
Springfield Hospital (Essex)
St Albans City Hospital
St Mary's Hospital
St Richard's Hospital
Sussex Orthopaedic NHS Treatment Centre
The Royal National Orthopaedic Hospital (Stanmore)
University College Hospital
University Hospital Aintree
University Hospital Llandough
York Hospital

Outliers for Knee revision rates, all linked primaries from 2015²

Barlborough NHS Treatment Centre (Derbyshire)
BMI Bath Clinic (Avon)
BMI The Meriden Hospital (West Midlands)
Guy's Hospital
Heatherwood Hospital
Hillingdon Hospital
King Edward VII Hospital Sister Agnes (Greater London)
Nuffield Orthopaedic Centre
Ormskirk and District General Hospital
Southmead Hospital
Spire Southampton Hospital (Hampshire)
Springfield Hospital (Essex)
Sussex Orthopaedic NHS Treatment Centre
The Lister Hospital (London)
The North East NHS Surgery Centre

Better than expected performance

This year we have again listed hospitals where revision rates are statistically better than expected. The lists here show units that lie below the 99.8% control limit which also achieved greater than 90% compliance across all of the NJR data quality audits. Units with lower data quality compliance are automatically excluded from these lists.

Better than expected for Hip revision rates, all linked primaries from 2010¹

Calderdale Royal Hospital
Ipswich Hospital
Luton and Dunstable Hospital
Musgrave Park Hospital
Nuffield Health Derby Hospital (Derbyshire)
Queens Medical Centre Nottingham University Hospital
Royal Derby Hospital
Royal Devon and Exeter Hospital (Wonford)
Royal Surrey County Hospital

Better than expected for Hip revision rates, all linked primaries from 2015²

Calderdale Royal Hospital
Ipswich Hospital
Royal Surrey County Hospital

Better than expected for Knee revision rates, all linked primaries from 2010¹

Bishop Auckland Hospital
BMI Alexandra Hospital Cheadle (Cheshire)
Burnley General Hospital
Calderdale Royal Hospital
Colchester General Hospital
Hexham General Hospital
Ipswich Hospital
Musgrave Park Hospital
Norfolk and Norwich Hospital
North Tyneside General Hospital
Nottingham Woodthorpe Hospital (Nottinghamshire)
Nuffield Health Derby Hospital (Derbyshire)
Nuffield Health Ipswich Hospital (Suffolk)
Princess Alexandra Hospital
Royal Derby Hospital
Spire Norwich Hospital (Norfolk)
Spire Parkway Hospital (West Midlands)
Stepping Hill Hospital
Worcestershire Royal Hospital

Better than expected for Knee revision rates, all linked primaries from 2015²

Ipswich Hospital
Musgrave Park Hospital
Spire Norwich Hospital (Norfolk)
The Cheshire and Merseyside Treatment Centre
The Horder Centre (East Sussex)

¹ Date range 15 February 2010 to 14 February 2020 inclusive.
² Date range 15 February 2015 to 14 February 2020 inclusive.

Overall in 2019, 145 NHS trusts and local health boards (comprising 251 separate hospitals) and 178 independent hospitals were open and eligible to report patient procedures to the NJR. All units except for one NHS trauma unit and two independent units submitted data in 2019. The proportion of all hip and knee joint replacements entered into the NJR compared to those entered in HES, is only available by NHS trust. No data on this is currently available from private providers and figures also exclude units in Northern Ireland as compliance data is not available.

At the time of publication, it has not been possible to produce compliance figures for the financial year 1 April 2019 to 31 March 2020 due to the unavailability of data from the Hospital Episodes Statistics (HES) service.

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

NHS hospitals

• 45% of NHS hospitals achieved a consent rate of greater than 95%
• 34% achieved a consent rate of 80% to 95%
• 21% recorded a consent rate of less than 80%
 
Independent hospitals

• 71% of independent hospitals achieved a consent rate greater than 95%
• 25% achieved a consent rate of 80% to 95%
• 4% recorded a consent rate of less than 80%

There has been an increase in recorded consent for all submitting units when compared to the previous year, with those achieving a higher than 95% rate returning to 55% from 50% in 2018. The proportion of all units achieving a higher than 80% consent rate, has also increased.

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

NHS hospitals

• 82% achieved a proportion of patients with a linkable NHS number greater than 95%
• 16% achieved a proportion of 80% to 95%
• 2% recorded a proportion of less than 80%

Independent hospitals

• 76% achieved a proportion of patients with a linkable NHS number greater than 95%
• 18% achieved a proportion of 80% to 95%
• 6% recorded a proportion of less than 80%

There has again been a drop in linkability from 2018, with the percentage of submitting units achieving over 95% in 2019 falling from 81% to 80%. The proportion achieving a greater than 80% linkability rate has remained the same at 96% compared with 2018.

Note: Independent hospitals might be expected to have lower linkability rates than NHS hospitals, as a proportion of their patients may come from overseas and do not have an NHS number.

Performance and data entry quality indicators are shown here for trusts and 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 2019 calendar year. Outcomes analysis after hip and knee replacement surgery is also provided for the period 2010 to 2020.

The full analysis for units can be found in the document available in the downloads section.