Hemiarthroplasty rather than total shoulder for glenohumeral arthritis: results with a pyrocarbon humeral head.

There is a surge of interest in the use of humeral hemiarthroplasty - rather than conventional total shoulder -  in the management of patients with glenohumeral arthritis. Many such procedures have been performed using a cobalt-chrome humeral head in the ream and run. Now there is growing use of Pyrocabon humeral heads with the idea that glenoid wear/humeral medialization could be lessened because of the special lubricating properties of their articular surface. 

Last month's post The Ream and Run - how much of an issue is glenoid wear? pyrocarbon vs. chrome cobalt? summarized some of the relevant data. 

This week a new study was published: Five-Year Radiographic and Clinical Outcomes of Pyrocarbon Hemiarthroplasty for Glenohumeral Arthritis and Osteonecrosis, which evaluated the progression of humeral head medialization in patients having pyrocarbon hemiarthroplasty. This was a methodologically strong study; it was a prospective FDA, IDE investigation. Standardized protocols were used from the start with predefined outcome measures. The inclusion rate was high: 45 of 54 potentially eligible patients. Rigorous imaging standards were imposed from the start and consistent across all time points. The radiographic analysis was blinded and used standardized software. The correlation analysis was formalized. Kaplan-Meier curves were carried out with 7 year survival rates. Radiographic measurements and patient reported outcomes were documented at three time points. 

Included patients had a mean age of 52 years and a mean follow-up of 73 months. In addition to the pyrocarbon humeral hemiarthroplasty, 60% had a glenoidplasty, 27% had glenoid drilling only, 9% had no glenoid treatment. 

Significant improvements were observed across all outcome measures. Patient satisfaction was 98%. The 7-year revision-free survival rate was 95.7%. Two patients were revised for infection. Posterior subluxation in decentered shoulders decreased from 27% preoperatively to 20% postoperatively. The mean medialization of the humeral head averaged 2.9  mm at the 2-year follow-up (1.5 mm/yr) and after that increased at a lower rate ( 0.3 mm/year) to an average of 4.0 mm at the time of the final follow-up of 6 years for an overall medialization of 0.66 mm/year. 

Interestingly, Pearson correlation analysis found no relationship between medialization and clinical outcomes. Patients with significant glenoid wear achieved the same results as those with minimal wear. Younger age was the only significant predictor of severe medialization (p=0.030), however this increased radiographic wear in younger patients did not correlate with worse clinical outcomes. In fact, none of the measured variables - including medialization, age, sex, glenoid morphology, and treatment type - correlated with clinical outcomes.

The wear in this pyrocarbon study can be compared to that in another 2025 study that used a chrome cobalt humeral head with reaming of the glenoid (the traditional ream and run): Characterizing glenoid wear after hemiarthroplasty with concentric glenoid reaming: a study of 113 arthroplasties at a mean of 6.7 years of follow-up. Both studies had similar age (59 yrs RnR and 52 yrs Pyro) and sex (92% RnR and 78% Pyro) profiles. 

The method of measuring medialization in the Pyro study

was similar to that used in Characterizing Glenoid Wear after Hemiarthroplasty with Concentric Glenoid Reaming: A Study of 113 Arthroplasties at a Mean of 6.7 Years

As seen in the figure below, the wear rates for the traditional ream and run do not appear inferior to those for Pyrocarbon. The traditional ream and run study demonstrated a plateau in wear beyond 6 years based on 11 time points. The trajectory of pyrocarbon wear is less certain in that it is based on 3 time points.

Both studies showed high satisfaction and improvement in clinical outcomes. The RnR study was retrospective with 113 of 408 patients included, 12 had open revision. The Pyro study was prospective with 45 of 54 patients included, 2 had open revision; the difference in revision rate was not statistically significant. Neither study found a relationship between glenoid wear and patient-reported outcomes. Formal correlation analysis (pyrocarbon) and group comparisons (ream-and-run) both showed that patients achieved excellent results (>97% satisfaction, significant functional improvement) regardless of wear amount. None of factors studied were associated with clinical outcome.

Clinical Implications: Humeral hemiarthroplasty - either traditional ream and run or pyrocarbon hemiarthroplasty - are important surgical considerations for young patients with glenohumeral arthritis, especially if they wish to avoid the risks and limitations associated with the polyethylene glenoid component used in total shoulder arthroplasty. Both procedures were associated with over 97% rate of satisfaction. While younger age was associated with increased wear, none of the factors considered in these studies - including glenoid wear - were associated with the clinical outcome.

Different heads

Pileated woodpecker

White headed woodpecker

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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link)
The total shoulder arthroplasty (see this link)
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link)
Shoulder rehabilitation exercises (see this link).