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 37 hospitals reported higher than expected rates of revision for knee replacement, and 23 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 10 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, we reported outlying hospitals based on all cases submitted to the registry since 1 April 2003. To reflect changes in hospital practices and component use, we now report outlying hospitals based on the last ten years (11 February 2012 to 11 February 2022) and five years of data (10 February 2017 to 11 February 2022 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.

Table 4.5 Outliers for hip mortality rates since 2017².
None identified

Table 4.6 Outliers for knee mortality rates since 2017².
None identified

Table 4.7 Outliers for hip revision rates, all linked primaries from 2012¹.
Basingstoke and North Hampshire Hospital 
Broadgreen Hospital 
Clementine Churchill Hospital (Middlesex) 
Fitzwilliam Hospital (Cambridgeshire) 
Hexham General Hospital 
Homerton University Hospital 
Hull Royal Infirmary 
Meriden Hospital (West Midlands) 
Milton Keynes Hospital 
North Tyneside General Hospital 
Nuffield Health Cheltenham Hospital (Gloucestershire) 
Nuffield Orthopaedic Centre 
Orthopaedics and Spine Specialist Hospital (Cambridgeshire) 
Salisbury District Hospital 
Southampton General Hospital 
Spire Hartswood Hospital (Essex) 
Spire Liverpool Hospital (Merseyside) 
Spire Methley Park Hospital (West Yorkshire) 
St Richard's Hospital 
The Tunbridge Wells Hospital 
Wansbeck Hospital 
Weston General Hospital 
York Hospital 

Table 4.8 Outliers for hip revision rates, all linked primaries from 2017².
Broadgreen Hospital 
Darent Valley Hospital 
Hexham General Hospital 
King Edward VII's Hospital Sister Agnes (Greater London) 
Milton Keynes Hospital 
North Tyneside General Hospital 
Nuffield Orthopaedic Centre 
Princess of Wales Hospital 
Wansbeck Hospital 
Weston General Hospital 

Table 4.9 Outliers for knee revision rates, all linked primaries from 2012¹.
Ashford Hospital 
Bath Clinic (Avon) 
Bishops Wood Hospital (Middlesex) 
BMI The South Cheshire Private Hospital (Cheshire) 
Broadgreen Hospital 
County Hospital Louth 
Ealing Hospital 
Goring Hall Hospital (West Sussex) 
Guy's Hospital 
Heatherwood Hospital 
Hillingdon Hospital 
Hinchingbrooke Hospital 
Hospital of St John and St Elizabeth (Greater London) 
King Edward VII’s Hospital Sister Agnes (Greater London) 
London Independent Hospital (Greater London) 
Meriden Hospital (West Midlands) 
Mount Vernon Treatment Centre 
Nevill Hall Hospital 
Nuffield Health Haywards Heath Hospital (West Sussex) 
Nuffield Orthopaedic Centre 
Orthopaedics and Spine Specialist Hospital (Cambridgeshire) 
Practice Plus Group Hospital - Southampton (Hampshire) 
Princess Royal Hospital 
Scarborough General Hospital 
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 Mary's Hospital (Isle of Wight) 
St Richard's Hospital 
Sussex Orthopaedic NHS Treatment Centre 
The Royal National Orthopaedic Hospital (Stanmore) 
Torbay Hospital 
University Hospital Llandough 
York Hospital 

Table 4.10 Outliers for knee revision rates, all linked primaries from 2017².
Ashford Hospital 
Bath Clinic (Avon) 
Guy's Hospital 
Hillingdon Hospital 
King Edward VII’s Hospital Sister Agnes (Greater London) 
Mount Vernon Treatment Centre 
Nuffield Orthopaedic Centre 
Queen Elizabeth The Queen Mother Hospital 
Southmead Hospital 
Spire Bushey Hospital (Hertfordshire) 
Spire Southampton Hospital (Hampshire) 
Springfield Hospital (Essex) 
Sussex Orthopaedic NHS Treatment Centre 
St Mary's Hospital (Isle of Wight) 
Yeovil District Hospital 

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.

Table 4.11 Better than expected hip revision rates, all linked primaries from 2012¹.
Calderdale Royal Hospital 
Goring Hall Hospital (West Sussex) 
Ipswich Hospital 
Musgrave Park Hospital 
Royal Surrey County Hospital 
Russells Hall Hospital 
Sunderland Royal Hospital 
Ulster Independent Clinic (Belfast) 

Table 4.12 Better than expected hip revision rates, all linked primaries from 2017².
Ipswich Hospital 

Table 4.13 Better than expected knee revision rates, all linked primaries from 2012¹.
Bishop Auckland Hospital 
Burnley General Hospital 
Craigavon Area Hospital 
Hexham General Hospital 
Ipswich Hospital 
Musgrave Park Hospital 
Norfolk and Norwich Hospital 
North Tyneside General Hospital 
Nottingham Woodthorpe Hospital (Nottinghamshire) 
Nuffield Health Cambridge Hospital (Cambridgeshire) 
Nuffield Health Derby Hospital (Derbyshire) 
Nuffield Health Ipswich Hospital (Suffolk) 
Nuffield Health Wolverhampton Hospital (West Midlands) 
Practice Plus Group Hospital - Emersons Green (Avon) 
Princess Alexandra Hospital 
Rotherham District General Hospital 
Spire Leicester Hospital (Leicestershire) 
Spire Norwich Hospital (Norfolk) 
Spire Parkway Hospital (West Midlands) 
Stepping Hill Hospital 
The Elective Orthopaedic Centre 
The Horder Centre (East Sussex) 

Table 4.14 Better than expected knee revision rates, all linked primaries from 2017².
None identified 

Note: ¹ Date range 11 February 2012 to 11 February 2022 inclusive. ² Date range 10 February 2017 to 11 February 2022 inclusive.

Overall in 2021, 139 NHS trusts and local health boards (comprising 253 separate hospitals) and 176 independent hospitals were open and eligible to report patient procedures to the registry. Data were not submitted in 2021 by nine NHS hospitals and three independent hospitals. 

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

NHS hospitals 
    39% of NHS hospitals achieved a consent rate of greater than 95% 
    34% achieved a consent rate of 80% to 95% 
    28% recorded a consent rate of less than 80% 

Independent hospitals 
    58% of independent hospitals achieved a consent rate greater than 95% 
    27% achieved a consent rate of 80% to 95% 
    14% 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 rising to 47%, from 43% in 2020 (56% in 2019). The proportion of all units achieving higher than 80% also increased slightly. The reduction in consent rate since 2019 can be related to the ratio of elective to trauma cases, which changed significantly during 2020, having a higher proportion of trauma cases compared to previous years. There was a significant reduction in elective cases due to COVID-19 and trauma cases have a higher rate where NJR consent is not obtained. 

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

NHS hospitals 
    77% achieved a proportion of patients with a linkable NHS number greater than 95% 
    18% achieved a proportion of 80% to 95% 
    5% recorded a proportion of less than 80% 

Independent hospitals 
    73% achieved a proportion of patients with a linkable NHS number greater than 95% 
    23% achieved a proportion of 80% to 95% 
    4% recorded a proportion of less than 80% 

In 2021, 76% of all submitting units achieved over 95% linkability, maintaining the rate seen in 2020 (80% in 2019). Units achieving 80 to 95% linkability also remained the same at 20%. 

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, the Isle of Man and Guernsey for the 2021 calendar year. Outcomes analysis after hip and knee replacement surgery is also provided for the period 2012 to 2022.

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