Knee Arthroplasty Infection

HAIBA case definition of deep infection after total knee arthroplasty

The HAIBA algorithm is based on operation and diagnosis codes from the National Patient Register (LPR) and microbiological sample responses from the Danish Microbiology Database (MiBa).

Primary knee arthroplasty (index surgery, see operation codes below) is divided into acute or planned, using diagnosis codes (see classification below).

The patient is followed for infections from 2 to 90 days after the index operation and up to 365 days. Patients with bilateral index surgery have two parallel follow-up periods.

An infection is recorded if a relevant re-operation has been recorded and at least two out of a minimum of three Kamme biopsy tests are positive for the same microorganism.

Knee

HAIBA case definition of knee arthroplasty (index operation)

Notes on surveillance data from HAIBA

As the estimated number of infections is relatively low, only national figures are presented online. Furthermore, only figures for infections occurring 2-90 days after the index surgery are shown online as the majority of infections occur in this period.

Figures on infections after acute index surgery are not presented online, but data on these infections and on infections occurring 91-365 days after the index surgery are made available to each of the Danish regions.

Data from HAIBA cover the past five full calendar years and the current year. Infections are calculated on a monthly basis in relation to the date of the index operation.

Which department/hospital are infections attributed to?

Infections are listed according to the date of the operation and the department where the operation was performed. As an example: An index operation was performed in Department X on January 2, 2016. Re-operation, during which an infection was found, was performed in Ward Y on February 10, 2016.

This infection is recorded in HAIBA as an infection in Department X on January 2, 2016.

How is incidence calculated?

The incidence of knee arthroplasty infections is calculated as a risk or cumulative incidence fraction, i.e. the number of infections per 100 index operations.

Operation codes of index operations

The HAIBA algorithm is based on primary hip replacements (index operations), which are defined by the operation codes from the LPR listed below. Surgery codes follow the Danish version of NOMESCO Classification of Surgical Procedures.  

Operation codes and texts:

KNGB20 - Primary total prosthetic replacement of knee joint not using cement
KNGB30 - Primary total prosthetic replacement of knee joint using hybrid technique
KNGB40 - Primary total prosthetic replacement of knee joint using cement

Diagnosis codes for acute index operation

Acute operations are separated from planned index operations by diagnosis codes; all index operations with a DS8* diagnosis code ("lesions of the knee and lower leg") are marked as acute; all others, as planned operations.

Diagnosis codes follow the Danish version of the International Classification of Diseases, 10th version (ICD-10) classification system.

Operation codes for reoperations

Re-operations that have been classified as relevant are defined with the following operation codes from the LPR.

Operation code and text:

KNGA02A - Open Exploration of soft tissue knee
KNGA12 - Open Exploration of knee joint
KNGA22A - Open biopsy of soft tissue of knee
KNGA22C - Open soft tissue biopsy of knee
KNGC20 – Sec. imp. of all comp. of total prosthesis in knee joint not using cement
KNGC21 - Sec. imp. of proximal comp. of total prosthesis in knee joint not using cement
KNGC22 - Sec. imp. of distal comp. of total prosthesis in knee joint not using cement
KNGC23 - Sec. imp. of patello-femoral comp. of total prosthesis in knee not using cement
KNGC29 - Sec. imp. of unspecified comp. of total prosthesis in knee joint not using cement
KNGC30 - Sec. imp. of all comp. of total prosthesis in knee joint using hybrid technique
KNGC31 - Sec. imp. of proximal comp. of total prosthesis in knee joint using hybrid technique
KNGC32 - Sec. imp. of distal comp. of total prosthesis in knee joint using hybrid technique
KNGC33 - Sec. imp. of patello-femoral comp. of total prosthesis in knee using hybrid technique
KNGC39 - Sec. imp. of unspecified comp. of total prosthesis in knee joint using hybrid technique
KNGC40 - Sec. imp. of all comp. of total prosthesis in knee joint using cement
KNGC41 - Sec. imp. of proximal comp. of total prosthesis in knee joint using cement
KNGC42 - Sec. imp. of distal comp. of total prosthesis in knee joint using cement
KNGC43 - Sec. imp. of patello-femoral comp. of total prosthesis in knee using cement
KNGC49 - Sec. imp. of unspecified comp. of total prosthesis in knee joint using cement
KNGC59 – Sec. imp. of interposition prosthesis in knee joint
KNGC99 - Other secondary prosthetic replacement in knee joint
KNGF02 - Open total synovectomy of knee
KNGF12 - Open partial synovectomy of knee joint
KNGG09 - Excision arthroplasty of knee
KNGG19 - Interposition arthroplasty of knee
KNGG29 - Other arthroplasty of knee without prosthetic replacement
KNGG49 - Fusion of knee joint with internal fixation
KNGG59 - Fusion of knee joint with external fixation
KNGH32 - Open Freeing of adhesions of knee joint
KNGH92 – Other open operation on knee joint
KNGK29 - Fenestration or forage of bone of knee or lower leg
KNGM79 - Bone transport operation of knee or lower leg
KNGQ09 - Exarticulation of knee joint
KNGQ99 - Other amputation or related operation on knee or lower leg
KNGS19 - Incision and debridement of infection of knee joint
KNGS29 - Incision and debridement of infection of bone of knee or lower leg
KNGS49 - Incision and debridement of infection of knee joint with intro. of therapeutic agent
KNGS59 - Incision and debridement of infection of bone of knee or lower leg with intro. of therapeutic agent
KNGS99 - Other operation for infection of tendon, joint or bone of knee or lower leg
KNGU10 - Removal of all comp. of total prosthesis from knee joint
KNGU11 - Removal of medial comp. of total prosthesis from knee joint
KNGU12 - Removal of lateral comp. of total prosthesis from knee joint
KNGU19 - Removal of unspecified comp. of total prosthesis from knee joint
KNGU99 – Removal of other implant from knee or lower leg
KNGW59 - Reoperation for superficial infection in surgery of knee or lower leg
KNGW69 - Reoperation for deep infection in surgery of knee or lower leg
KNGW89 - Reoperation for deep haemorrhage in surgery of knee or lower leg
KNGW99 - Other reoperation in surgery of knee or lower leg

 Material codes for Kamme biopsy

 The following codes are used to identify all samples taken as Kamme biopsies. These are material codes from Mikrobiologisk Diagnose System (MDS). Read more about the MDS.

Material code and text:

40000 - Tissue
40010 - Biopsy
40030 - Bone tissue
40035 - Package Kamme biopsies
40065 - Joint capsule tissue

All biopsies with sampling time in the interval from 24 hours before re-operation to 48 hours after re-operation are treated as a single set of biopsies.