The effect of ROSA-assisted knee arthroplasty on clinical outcomes

to compare improvement in arthrosis symptoms between patients operated with

ROSA-assistance and conventionally operated patients one year after surgery

Patient-reported outcome measures (PROMs), including OKS, EUR5D-5L, WOMAC, Pain

Catastrophizing Scale, Pain Sensitivity Questionnaire will be collected through

Phillips Vital Health, as explained in 8.1.1.

Surgical outcomes include #complications, duration of surgery, blood loss,

length of hospital stay, medication, anesthesia, analgesia and are documented

in the surgery report and available through SAP. Stability, implant position,

mobility, mechanical axis of the leg will be extracted from the ROSA-software.

Accuracy of surgical plan (#adaptations, #procedures without deviations from

plan) including implant size and level of resection and documented during

surgery using the ROSA-software. Logistic outcomes of surgery include surgery

ward occupation duration including preparation, operation duration (incision to

bandage), anaesthesia, transition from one patient to next, and is collected

through the BOZIS-system of Zuyderland Medical Center.

Clinical outcomes include alignment of the leg, 90-day and 1-year survival

implant and survival patient, reason for revision, type of revision will be

retrieved from electronic medical chart abstraction (SAP NetWeaver for Windows

10, V760 Final Release). Alignment (deviation, #outliers) will be assessed

before TKA and 3 months after surgery using a CT scan, per (pre-operative)

routine practice .

Physical activity and weight bearing will be assessed for 7 continuous days

using hip-worn accelerometers.

Metabolic outcomes include metabolic syndrome, body composition and handgrip

strength.

Metabolic syndrome will be quantified binary or as continuous scale. Binary

classification will be performed per present AHA/NHLBI ATPIII-criteria: at

least 3 out of 5 measures:

• waist circumference >=102 cm in men or >=88 cm in women;

• triglycerides: >=150 mg/dL (1.7 mmol/L), or on drug treatment for elevated

triglycerides;

• HDL-Cholesterol: <40 mg/dL (1.03 mmol/L) in men or <50 mg/dL (1.3 mmol/L) in

women or on drug treatment for reduced HDL-C;

• blood pressure: >=130 mm Hg systolic blood pressure, >=85 mm Hg diastolic blood

pressure, antihypertensive drug treatment;

• fasting glucose: >=5.3 mmol/L or on drug treatment for elevated glucose (20).

As continuous variable, we will utilize the Metabolic Syndrome Severity Scale

(MSSS) (21, 22):

• Males: -4.5639 + 0.0108*WC - 0.0254*HDL + 0.0040*SBP + 0.9085*ln(Tri)

• Females: -5.8119 + 0.0197*WC - 0.0149*HDL + 0.0067*SBP + 0.8585*ln(Tri)

Body Composition will be measured using bioimpedance analysis (Tanita DC 360 S,

Amsterdam, The Netherlands).

Strength and fitness will be assessed as handgrip strength using hand-held

dynamometer (Jamar, Sammons Preston, Inc., Bolingbrook, IL, US), and 2-minute

walking, 30-second sit-to-stand, and timed-up-and-go tests.

Economic Outcomes

Cost of procedure (to hospital) including operation duration (room &

personnel), healthcare costs (to payer) including hospitalizations, medical

procedures, medications, outpatient clinic visits etc, productivity costs (paid

work due to absenteeism, unpaid work), paid and unpaid care, and their offset

to the clinical outcomes (cost-efficiency). Cost of procedure, medical

consumption, healthcare and productivity costs will be assessed using validated

questionnaires (iMTA Productivity Cost Questionnaire (iPCQ), iMTA Medical

Consumption Questionnaire (iMCQ)). Duration until, and quality of,

return-to-work will be inquired via previously developed questionnaires.

Cost-efficiency of the procedure will be calculated as cost per

quality-adjusted life expectancy (QALE)7. Cost-efficiency will be compared

between study groups; in addition, the most progressive threshold of

cost-efficiency in orthopedic procedures of 50,000$/QALY will be used as

reference.8-10 Work (re-)integration will be assessed by validated

questionnaires (Work Ability Index WAI, Work Productivity and Activity

Impairment WPAI) on autonomy, work productivity, and work-home-interference.



8.1.3 Other study parameters

Other study parameters include gait and proprioception, and will be optional

for patients (see study design).

Gait will be assessed using the 3D VICON motion capture system. This system

uses 8 infrared cameras to follow movement. This measurement will be executed

under expert supervision of Zuyd Hogeschool staff.

Proprioception of the knee will be measured in a motorized carriage. Patients

will lay on a hospital bed where their leg is fixed in the motorized carriage.

This sled will passively extend and flex the knee. When patients get the

sensation of movement, they have to push a button. The reaction time and the

angle to sense the movement will be measured digitally.

24/7-glucose profiles will be assessed using continuous glucose monitors

(Freestyle Libre, Abbott Medical Nederland B.V., Veenendaal, NL).