Training and experience are matters of record. Here is what the record can and cannot tell you.

Fellowship training in adult reconstruction is a documented year of specialisation

An orthopaedic surgeon completes a five-year residency. A fellowship-trained adult reconstruction surgeon has then spent at least one further year training in hip and knee replacement, including atypical deformity, dysplasia, and replacement after trauma ¹. The American Association of Hip and Knee Surgeons requires its fellow-level members to be board certified and to do at least 50 hip or knee replacements a year ¹.

In one institution's 16,882 joint replacements, hips done by fellowship-trained surgeons had shorter operating times, 90 against 113 minutes, shorter hospital stays, and 25 percent lower opioid use, and patients went home rather than to a facility more often ². A national database study of hip replacement found fellowship-trained surgeons took on more complex patients and still had a lower overall complication rate, 12.4 against 13.8 percent, and a lower five-year revision rate, 3.9 against 4.3 percent ³.

Those are population differences, and modest ones. A fellowship is a fact about training, not a guarantee about any one operation.

The volume studies found a relationship, and defined volume differently each time

A systematic review of 11 studies on surgeon volume and knee replacement found that low volume was defined anywhere from fewer than 3 to fewer than 52 operations a year, and high volume from more than 5 to more than 70 ⁴. Across those studies, low surgeon volume was associated with more infection, longer operations, longer hospital stays, more transfusions, and worse patient-reported outcomes ⁴. Mortality, blood clots, and implant survival were not associated with surgeon volume, and the authors wrote that the results must be interpreted with caution ⁴.

A later analysis let the data set its own thresholds. For knee replacement it identified four surgeon bands, 0 to 12, 13 to 59, 60 to 145, and 146 or more a year, with complication rates falling across each band ⁵. Revision rates fell too, but not between the top two bands ⁵. For hospitals the bands were 0 to 89, 90 to 235, 236 to 644, and 645 or more a year, with complications no longer falling above 236 ⁵.

For hip replacement, an Ontario study identified a threshold of 35 operations a year. Patients whose surgeon had done 35 or fewer in the prior year had more dislocations, 1.9 against 1.3 percent, and more early revisions, 1.5 against 1.0 percent ⁶. A US analysis of 352,131 hip replacements by 5,106 surgeons put its threshold at 109 a year, above which dislocation, infection, readmission, and in-hospital death were all less likely ⁷.

A meta-analysis of 68 studies found that each additional 50 knee replacements a hospital does per year was associated with about 9 percent lower odds of death within three months, and no clear association for deep infection or late revision ⁸.

A number is a record, not a verdict

The US hip study shows what a single cutoff misses. Of the surgeons below its 109-a-year threshold, 87.8 percent had dislocation rates lower than the average for all surgeons in the study ⁷. The relationship holds across a population, not for individuals.

The thresholds also disagree with each other: 35, 109, 60, 146, depending on the study, the joint, the outcome, and the country ⁵⁶⁷. That is what a population finding looks like when the question is asked several ways.

• Fellowship training is a documented fact about how a surgeon trained ¹.
• Annual volume is a documented fact about how much a surgeon operates, and the studies define it differently ⁴.
• Neither fact, on its own, predicts how a particular operation will go ⁴⁷.

What a candid conversation about approach and implant sounds like

A candid surgeon will name the approach they plan and say why it suits your anatomy, rather than presenting it as the only one. They will name the implant and say how long that design has been in use and what registry follow-up it has. They will say what they do when something goes wrong, and who else will be in the room.

The clearest sign is specificity. A plan that mentions your X-ray, your deformity, your other health conditions, and your goals has been made for you. A plan that would read the same for anyone has not yet been.

What to ask your surgeon

• Did you complete a fellowship in adult reconstruction, and where?
• Roughly how many hip and knee replacements do you do in a year, and how many at this hospital?
• Which approach do you plan for me, and why this one for my anatomy?
• Which implant will you use, how long has it been in use, and what does the registry data show for it?
• What complications have you seen in patients like me, and how did you manage them?

Training and volume are records you are entitled to ask about. What they mean for your operation is decided with your surgeon, from your exam, imaging, and history.