Dr. Donald Weimer, M.D.

Orthopedic Surgery

45 procedures4 hospitalsO Fallon, ILUpdated May 2026

Contact & Location

618-641-5800
Phone: 618-641-5800
Practice phone listed in the NPI registry
1512 N Green Mount Rd, Suite 300
O Fallon, IL 62269
Current practice address per the CMS NPPES registry (self-reported to the registry, last updated August 2015). Registry checked August 2026.
NPI: 1932152980
Credentials: M.D.
Active Medicare provider (NPI verified)
20 years of practice experience
Licensed M.D.
Licensed surgical specialist
Board-certified orthopedic surgeon
Contact information available
Find Practice on Google Maps
National Comparison by Procedure
Knee 19 vs 45 national avg 0.4x
avg
Shoulder 26 vs 29 national avg 0.9x
avg

Compared with 6,612 knee surgeons and 2,217 shoulder surgeons in the 2024 Medicare dataset.

Dr. Weimer performs more shoulder replacement procedures than 62% of orthopedic surgeons in Illinois, based on 2024 Medicare claims volume.Derived from the state ranking shown on this page: #30 of 80 ranked shoulder surgeons in Illinois.

About Dr. Weimer

Practice. Dr. Donald Weimer is a board-certified orthopedic surgeon practicing in O Fallon, Illinois. The latest annual CMS data records 26 shoulder replacements and 19 knee replacements, 45 procedures in all. That is #30 in Illinois for shoulder replacement. A Medicare provider since 2006.

Trend. Medicare records run from 2013 to 2024, 12 years. Volume rose from 37 procedures a year to 45, up 22%.

National context. Among 2,217 shoulder replacement surgeons tracked nationally, 26 procedures is near the national average of 29.

Local context. O Fallon has 2 orthopedic surgeons in the current Medicare data. Comparing volume and procedure mix across them is one way to narrow a shortlist.

Verified Medicare Cases

Shoulder Replacement
26 verified cases
#30 in Illinois
Knee Replacement
19 verified cases
#198 in Illinois
Estimated 2024 total: 140 – 170 procedures (all insurers)
Medicare fee-for-service share of national volume in 2024: 29% to 37% for shoulder replacement, 23% to 28% for knee replacement
How is this estimated?

Medicare Part B fee-for-service claims are one payer stream among several, and the share they represent differs by procedure. In 2024 it was 29% to 37% for shoulder replacement, 23% to 28% for knee replacement. Each verified count above is divided by its own procedure's range, and the results are added, to estimate total practice volume across all payers. The verified Medicare count is the definitive, audited figure; this is a range derived from published national volume projections, not a measurement, and an individual practice can sit well outside it: how these ranges are derived, and their sources.

How Dr. Weimer Compares

Procedure volume compared to the Illinois state average.

Knee Below Avg
19 Avg: 50
Shoulder Average
26 Avg: 27
Dr. Weimer Illinois Average

Volume Trend Analysis

Dr. Weimer's Medicare-recorded procedure volume has trended upward over 12 years, increasing 22% from 37 procedures in 2013 to 45 in the most recent data.

Years of Data 12
2024 Volume 45
Peak Volume 45 (2021)
Trend Growing

Hospital Affiliations & Quality

H
Hshs St Elizabeth'S Hospital
4/5
O Fallon, IL
Similar to national avg
H
St Josephs Hospital
4/5
Breese, IL
Low case volume
H
Memorial Hospital
4/5
Belleville, IL
Similar to national avg
H
Sparta Community Hospital
Sparta, IL
Low case volume

Quality ratings and complication rates are hospital-level metrics from CMS Hospital Compare and do not reflect individual surgeon performance. Star ratings updated quarterly. Complication data covers a rolling 3-year period.

Patient Resources: Preparing for Shoulder Replacement

If you are considering shoulder replacement surgery, these evidence-based guides can help you prepare and recover:

Shoulder Replacement Recovery Overview

Recovery timelines vary by patient, but here is a general overview of what to expect after shoulder replacement surgery:

Week 1-3 Arm in a sling for protection. Gentle pendulum exercises under therapist guidance. Focus on pain management and wound care.
Week 4-6 Gradual sling weaning. Begin passive and active-assisted range-of-motion exercises. Light daily activities resume.
Week 7-12 Active range-of-motion exercises. Light strengthening begins. Most patients can drive and perform desk work.
Month 4-6 Progressive strengthening continues. Return to most activities. Full recovery may take 6-12 months for complete shoulder strength.

Individual recovery varies based on overall health, age, and adherence to physical therapy. View full shoulder replacement recovery guide and product recommendations

Frequently Asked Questions About Dr. Weimer

How does Dr. Weimer's procedure volume compare to other Illinois surgeons?

Dr. Weimer has performed 45 Medicare-verified joint replacement procedures. The Illinois average is 69 procedures per surgeon. Medicare data captures roughly one-third of all joint replacements, so total volume may be higher. Dr. Weimer ranks #166 out of 316 orthopedic surgeons in Illinois.

What types of joint replacement does Dr. Weimer perform?

Dr. Weimer's Medicare data shows procedures in shoulder replacement (26 cases) and knee replacement (19 cases).

Are there other orthopedic surgeons near Dr. Weimer in O Fallon?

Yes. There are 2 orthopedic surgeons in O Fallon in the current Medicare dataset. Patients can compare procedure volumes and specializations to choose the surgeon who best fits their needs. Use the state page to view all Illinois surgeons.

What does the Medicare data for Dr. Weimer represent?

The procedure counts shown are based on 2024 Medicare Part B fee-for-service claims data, published by the Centers for Medicare and Medicaid Services (CMS). Medicare fee-for-service is only one payer stream, and the share of national volume it represents differs by procedure. In 2024 the share was 29% to 37% for shoulder replacement, 23% to 28% for knee replacement, which puts Dr. Weimer's total volume across all insurers at roughly 140 to 170 procedures against the 45 verified here. Those shares are derived from published national volume projections rather than quoted from a single publication, and they are estimates with real uncertainty. The OrthoProcedures methodology page shows the full derivation, the sources, and the limits at orthoprocedures.com/data-methodology.html.

Has Dr. Weimer's procedure volume changed over time?

Yes. Dr. Weimer's Medicare-recorded volume has increased from 37 procedures in 2013 to 45 in the most recent data, a 22% increase over 12 years. This upward trend suggests an expanding joint replacement practice. Peak volume was 45 procedures in 2021.

Does Dr. Weimer perform more than one type of joint replacement?

Yes. Dr. Weimer's Medicare data shows procedures in shoulder replacement (26 cases), knee replacement (19 cases). Surgeons who perform multiple joint replacement types maintain broad technical skills across different anatomical joints.

Which hospitals is Dr. Weimer affiliated with?

According to CMS facility affiliation data, Dr. Weimer is affiliated with Hshs St Elizabeth'S Hospital, St Josephs Hospital, Memorial Hospital, Sparta Community Hospital.

What are the quality ratings for hospitals where Dr. Weimer practices?

Hshs St Elizabeth'S Hospital (4 out of 5 CMS stars, hip/knee complication rate similar to national average); St Josephs Hospital (4 out of 5 CMS stars, insufficient case volume for complication rate comparison); Memorial Hospital (4 out of 5 CMS stars, hip/knee complication rate similar to national average). These are hospital-level quality metrics from CMS Hospital Compare and do not reflect individual surgeon outcomes.

Other Orthopedic Surgeons in O Fallon, Illinois

Dr. Weimer's 45 Medicare procedures are below the O Fallon average of 57. The table below compares verified procedure volumes for orthopedic surgeons practicing in O Fallon.

SurgeonProceduresSpecialties
Dr. Kevin McCarthy 69 Hip, Knee

Patient Resources & Verification

Research reviews, verify credentials, and check official quality data through these trusted sources:

Medicare Care Compare and NPI Registry are official U.S. government sources. Google reviews reflect user-submitted feedback. OrthoProcedures.com does not verify the accuracy of third-party review content.

Cite This Data

APA: OrthoProcedures. (2026). Dr. Donald Weimer, M.D. -- Orthopedic Surgeon Profile. Retrieved from https://orthoprocedures.com/surgeons/il/dr-donald-weimer-o-fallon.html

Link: https://orthoprocedures.com/surgeons/il/dr-donald-weimer-o-fallon.html

Data source: CMS Medicare Part B Provider Utilization & Payment Data. Full methodology | Open Data API

Important: Rankings are based solely on Medicare procedure volume and do not reflect quality of care, patient outcomes, or procedures covered by private insurance. This data represents approximately one-third to 40% of all joint replacement procedures nationwide. Always consult with healthcare providers to make informed decisions about your care.