High Completeness and Accurate Reporting of Key Variables Make Data from the Danish Shoulder Arthroplasty Registry a Valuable Source of Information

Figures & data

Table 1 Validation of Key Variables in the DSR

Key Variables Registered in DSR	Medical Records		PPV
	Yes	No	% (95% CI)
Patient Characteristics
Sex	276	0	100 (99–100)
Age	264	12	96 (93–98)
Side of surgery	270	6	98 (95–99)
Indication*
Arthritis	13	5	72 (47–90)
Type of arthritis	8	5	62 (32–86)
Osteoarthritis	101	9	92 (85–96)
Type of osteoarthritis	64	35	65 (54–74)
Fracture	107	3	97 (92–99)
Fracture age	96	1	99 (94–100)
Fracture healing	23	2	92 (74–99)
Rotator cuff arthropathy	77	5	94 (86–98)
Humeral head necrosis	7	5	58 (28–85)
Others	3	6	33 (8–65)
Previous Surgery*
All types of previous surgery	22	8	73 (54–88)
Surgery for instability	2	2	50 (7–93)
Synovectomy	2	4	33 (4–78)
Osteosynthesis	7	1	88 (47–100)
Cuff reconstruction	5	2	71 (29–96)
Decompression	4	4	50 (16–84)
AC resection	2	1	67 (9–99)
Surgery for infection	3	0	100 (29–100)
Arthroscopy	3	5	38 (9–76)
Other	1	2	33 (1–91)
Brand	230	44	84 (79–88)
Arthroplasty Type
Hemiarthroplasty	137	29	83 (76–88)
Total Shoulder Arthroplasty	36	11	77 (62–88)
Bipolar	1	0	100 (3–100)
Resurfacing	14	1	93 (68–100)
Reverse	38	8	93 (80–98)
Humeral Component
Fixation technique	36	4	90 (76–97)
Glenoid Component
Fixation technique	55	6	90 (80–96)
Material	62	2	97 (89–100)
Anchor design	21	5	81 (61–93)

Notes: Medical records: The number of the key variables registered in the DSR and confirmed (yes/no) in the medical records. The percentage of the registrations in the DSR confirmed by medical records. *Multiple indication for a single surgery is possible.

Abbreviations: PPV, positive predictive value; CI, confidence interval.

Table 2 Completeness of Reporting

Year	DSR, n (%)	*DNRP and DSR, n (%)	Completeness, % (95% CI)
2006	591 (7)	727 (7)	81.3 (78.3–84.1)
2007	774 (8)	813 (8)	95.2 (93.5–96.6)
2008	822 (9)	859 (9)	95.7 (94.1–96.9)
2009	907 (10)	976 (10)	92.9 (91.1–94.5)
2010	934 (10)	1008 (10)	92.7 (90.9–94.2)
2011	937 (10)	996 (10)	94.1 (92.4–95.5)
2012	1025 (11)	1072 (11)	95.6 (94.2–96.8)
2013	1028 11)	1064 (11)	96.6 (95.3–97.6)
2014	1086 (12)	1108 (12)	98.0 (97.0–98.8)
2015	1104 (12)	1127 (12)	98.0 (97.0–98.7)
Total	8976 (100)	9750 (100)	94.4 (94.4–94.4)

Note: *Number of unique arthroplasties in the DSR + Number of unique arthroplasties in the DNPR + Number of unique arthroplasties in both DSR and DNPR.

Abbreviation: CI, confidence interval.

Table 3 Missing Data in Key Variables Within the Danish Shoulder Arthroplasty Registry

Key Variables from the DSR	Completeness
	Rate	Percentage
	Complete Cases/Total Cases	%
Patient Characteristics
Sex	8976/8976	100
Age	8976/8976	100
Side of surgery	8976/8976	100
Indication	8961/8976	100
Previous Surgery	8895/8976	99
Brand	8965/8976	100
Arthroplasty type	8955/8976	100
Humeral Component
Fixation technique*	1637/2838	58
Glenoid Component**
Fixation technique	2413/3015	80
Material	2286/3015	76
Anchor design	2497/3015	83

Notes: *Inactive from January 1 2010, **only relevant for implant with a glenoid component.