Case #147

Case 2011-MDC08-01 Major knee operations

Added by Anonymous over 7 years ago. Updated over 7 years ago.

Status:AcceptedStart date:2014-01-03
Priority:NormalSpent time:-
Target version:Expert Group 2011
Initiator:Sweden Target year:2012
MDC:MDC08 Owner / responsible:
Target Grouper:COMMON, DEN, EST, FIN, ICE, LAT, NOR, SWE Old forum status:CLOSITEM - Closed item


Last updated: 2011-04-20
Status: CLOSITEM - Closed item
Initiated: 2010-01-28
By: Lennart Adamsson, KS; Magnus Forssblad, Capio Artro Clinic; (both via Barbro Ohde) and Mats Brittberg, Kungsbacka (via Annica Tallmer) and others/NPK, Sweden
Expert Network 2011-03-17 - Change recommended
Board 2011-04-04 - Recommendation accepted


CPK ID 349


All knee operations (except prosthetic replacements and diagnostic arthroscopy) on outpatients are grouped to one single group, DRG 222O (Knee procedures, short therapy). This causes a casemix problem. More expensive procedures, like cartilage transplantation or repair of cruciate ligaments, that are performed only in some clinics are systematically underpaid which causes an incitement to treat the cases as inpatients although an outpatient treatment is possible. Other clinics (private?) that concentrate on the less expensive procedures are systematically overpaid.

Therefore the initiators request a split of DRG 222O into two groups, one for major procedures and one for other procedures.

Mats Brittberg specifies the procedures that they consider as major in Appendix 1.

Analysis by NPK (former CPK)

We also included the inpatient group, DRG 222 (Knee procedures w/o cc) in the analysis since that DRG, according to the grouping logic, contains exactly the same procedures as DRG 222O. DRG 221 (Knee procedures w cc) also contains these procedures, but cost data are affected by different CC factors.

Cost data for the analysis is from the Swedish KPP database for 2009 grouped with NordDRG version 2011. Costs per DRG and per procedure are reported in Appendix 2.

All tables below are extracted from that appendix.

Inpatient analysis

Some of the procedures characterised as major by Brittberg already have CC property (NGS- & NGW-codes) and they will be grouped to DRG 221. Cost data shows that this is appropriate. See the tables below.

We studied if the other procedures characterised as major by Brittberg are so expensive that they also can fit in DRG 221, even without any CC factor. Se the table below.

The table shows that Brittbergs “major cases” are more expensive than the others in DRG 222 but they are not expensive enough to fit in DRG 221, even though we included the cost outliers in DRG 222 but not in DRG 221. We got a similar result even when we excluded the less expensive procedures from Brittbergs list of “major cases”. See the table below. (The excluded cases are marked with red in the table ”DRG 222 - all cases” in appendix 2.)

We then studied the transplantation cases, which are pointed out as most expensive by Brittberg and found that these can fit in DRG 221. Se the table below. (The transplantation cases are marked with green in the table ”DRG 222 - all cases” in appendix 2.)

The procedure code NGN29 (Heterotransplantation av ben till knä eller underben) was not marked as major by Brittberg and there were no cases in the KPP database either, but we think that this code can be handled like the other transplantation codes in the grouping logic.

Outpatient analysis

The procedure NGE01 (Artroskopisk eller endoskopisk incision i eller sutur av ledkapsel i knäled) is included in Brittbergs “major cases” but this is not a very complicated procedure and cost data also shows that it is less expensive than the average fore the whole DRG 222O, both in the table with cost outliers (”DRG 222O - all cases” in appendix 2) and in the table without (”DRG 222O - outliers excluded” in appendix 2).

Therefore the procedure NGE01 was excluded from “major cases” in the analysis. (There are more procedures classified as major with lower costs than the average for the whole DRG 222O but the type of procedure and/or the low number of cases indicate that cost data for these cases are unreliable.)

The analysis showed that the criteria for a DRG split are fulfilled, both concerning the number of cases and the cost differences. The result was similar irrespectively if outliers were included or not. See the tables below.

For 30 of the 66 procedures considered as “major” by Brittberg there were no cases in the KPP database for outpatients. They are probably very seldom performed on outpatients but to complete the analysis we judged them clinically, one by one, and we think that NGF20 (Fixation av ledytefragment i knäled, perkutan eller sluten) and NGH31 (Artroskopisk eller endoskopisk adherenslösning i knäled) can be excluded from the “major list” (together with NGE01 as mentioned above).

Brittberg does not mark reoperation for wound dehiscence (NGW49) or reoperation for superficial haemorrhage (NGW79) as major and that is probably correct in outpatients. There were no such cases in the Swedish KPP database for outpatients.

Analysis summary

The analysis shows that the transplantation cases in DRG 222 are so expensive that they fit better in DRG 221 and that a split of DRG 222O into ”major” and ”other” is motivated. The procedures that can be considered as major according to cost data (or clinical judgment when cost data was missing) are listed in the table “Major procedures” in appendix 2.

Suggestion by NPK

We suggest a change in the DRG grouping logic for 2012 so that:

  • transplantation cases in DRG 222 will be grouped to DRG 221
  • DRG 222O is divided into one group for major knee procedures (DRG 222P) and one group for other knee procedures (DRG 222O).

Technical changes to achieve that are proposed in appendix 3.


Expert Network 2011-03-17

The meeting recommended acceptance of the proposal to split DRG 222O.

A new DRG is introduced with the code 222P and the text “Major knee procedures, short therapy”.

The text for DRG 222O is changed to: “Other knee procedures, short therapy”.

A new procedure property called “Major knee procedure” is introduced. The code can be 08S70 (if not occupied in any national version).

To the 6 transplantation codes add a new procedure property.

The case will be closed.

Martti Virtanen 2011-03-29

The problem of transplant operations turns out to be more problematic than originally imagined. The Finnish version of NCSP logically has left out all codes for using transplantation. This is based on the fact that there is no single procedure for transplantation but instead transplants are used as part of other procedures that have their own codes. For example in vertebroplasty (NASK49) one quite often uses transplant as a method. The Finnish system has chosen to use the Z-codes for transplant use in this situation. The Finnish system includes a more detailed description of the technique than NCSP common version (for example ZTXH21 ‘Autograft of bone in small pieces’, ZTXH22 ‘Autograft of bone in block’, ZTXH29 ‘Autograft of bone, unspecified’), However, the other versions of NCSP include at last of these codes. There are also several other Z-code options. This makes it possible to code the same situation in two ways.

For the DRG problem one could use a diagnosis property for all the codes at issue to solve the problem. However it becomes obvious that there are other locations (NASN, NBSN, etc) not just knee (NGSN) where cost structure is probably similar to knee.

Since the change was not originally demanded by clinicians I would propose that this item is analysed for NordDRG 2013 taking in account all areas and all possibilities for coding.


Technical change 2011-03-28

A new DRG is created:

  • 222P “Major knee procedures, short therapy”

A new rule is added to Drglogic table before current line 108D1200.
The new line has following properties: ICD = +, MDC = 08, OR = S, Procpro1 = 08S70, Disch = N, Dur = <2.

The text of DRG 222O is changed to “Other knee procedures, short therapy”.

New procedure property 08S70 ‘Major knee procedures, short therapy’ is created.

Following codes (and linked national version codes) are given the new property 08S70:

Technical change 2011-04-07

The list of procedures with 08S70 must be complemented with the following:

DRG change 2011-03-28

Cases with major knee operations in outpatient care are assigned to DRG 222P.


NordDRG 2012

CPK-ID-349_Appendix_1.xls (44.5 KB) Anonymous, 2014-01-03 10:25

CPK-ID-349_Appendix_2.xls (117 KB) Anonymous, 2014-01-03 10:25

2011_MDC-08_01.jpg (20.6 KB) Anonymous, 2014-01-03 10:42

2011_MDC-08_02.jpg (15.6 KB) Anonymous, 2014-01-03 10:42

2011_MDC-08_03.jpg (15.6 KB) Anonymous, 2014-01-03 10:42

2011_MDC-08_04.jpg (22.7 KB) Anonymous, 2014-01-03 10:42

2011_MDC-08_05.jpg (57.4 KB) Anonymous, 2014-01-03 10:42

2011_MDC-08_06.jpg (99.8 KB) Anonymous, 2014-01-03 10:43

2011_MDC-08_07.jpg (52 KB) Anonymous, 2014-01-03 10:43

2011_MDC-08_08.jpg (52 KB) Anonymous, 2014-01-03 10:46

CPK-ID-349_Appendix_3.doc (66 KB) Anonymous, 2014-01-03 10:53


#1 Updated by Anonymous over 7 years ago

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