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    For TSA Patients, Press-fit Short Stems Offer Significant Functional Improvement

    Dr. Brent Morris discusses a study he and his colleagues conducted to evaluate clinical and radiographic outcomes 2 years after primary total shoulder arthroplasty with either a grit-blasted or proximal porous-coated press-fit short stem.

    A study recently published in the Journal of Shoulder and Elbow Surgery [1] has added to – and confirmed – the small but growing body of literature showing that primary anatomic total shoulder arthroplasty (TSA) patients who receive press-fit short stems demonstrate clinical improvement at short-term follow-up, with minimal radiographic changes and few complications.

    The study was also presented in March at the 2018 Annual Meeting of the American Academy of Orthopaedic Surgeons in New Orleans. [2]

    For the study, the researchers used a prospective shoulder arthroplasty registry to identify 118 patients who had undergone anatomic TSA with a press-fit short-stem and had at least 2 years of follow-up. Two types of stems were used: grit-blasted (n=85) and proximal porous-coated (n=33). Patient age at surgery ranged from 25 to 93 years (average 66.7 years), with follow-up of 2 to 5 years (average 3 years).

    Patients underwent surgery for:

    • Glenohumeral arthritis (n=100)
    • Instability arthropathy (n=10)
    • Post-traumatic arthritis (n=4)
    • Failed prior arthroplasty (n=3)
    • Inflammatory arthropathy (n=1)

    All shoulder function scores – Constant, ASES, WOOS, and SANE – improved significantly from the preoperative evaluation to the final follow-up. That was also true of forward flexion, abduction, and external rotation (P<0.001 for all). Three female patients with grit-blasted stems had undergone revision for humeral component loosening at less than 1 year after surgery, but none of the patients who had a minimum of 2 years of follow-up showed any signs of stem loosening on radiographs.

    Radiographs also showed:

    • Radiolucent lines without humeral component loosening in 7 patients (5.9%), all in patients with grit-blasted stems
    • Osseous resorption at the medial cortex in 11 patients (9.3%), 1 patient with a proximal porous-coated stem and 10 patients with grit-blasted stems
    • Osseous resorption at the medial cortex in 5 of the 7 patients with radiolucent lines (71.4%)

    Brent J. Morris, MD, from the Fondren Orthopedic Group in Houston, Texas, said he and his colleagues, “are unsure of the long-term implications of the medial bone resorption, but we did not see any evidence of stem loosening or impact on clinical outcomes with this radiographic finding at 2 years of follow-up. Medial calcar bone resorption has long been reported with press-fit long stem components, and the hope was that we would not see this phenomenon with shorter press-fit stems.

    “Overall, we were very pleased with the results of the press-fit short stem implant, especially with the addition of the proximal porous coating on the newer stem utilized in the study. Radiographs of the proximal porous-coated stem group did not show any radiolucent lines, compared with 8.2% of radiographs of patients with the older grit-blasted short stem, which lacked the proximal porous coating.”

    The press-fit short stem has become the stem of choice for nearly all primary anatomic TSAs Dr. Morris performs, “with the exception of selected cases where I use a stemless or canal-sparing press-fit implant,” he said. “Press-fit long stem and cemented components are typically reserved for some revision cases or, potentially, patients with severe inflammatory arthropathy, such as rheumatoid arthritis, or particularly poor metaphyseal bone.

    “However, even in these settings, I trial first with the press-fit short stem and assess the bone quality intraoperatively before upsizing to a long stem or before considering cementing.”

    Complications in this study were rare: 4 intraoperative (2 anterior cortex fractures and 2 lesser tuberosity fractures) and 2 postoperative (1 periprosthetic infection and 1 posterior dislocation). “We noted a few early complications with stem placement in varus with a non-coated stem; fortunately, the proximal porous coating was added,” Dr. Morris said. “We also modified our surgical technique to avoid varus stem placement, given the early case experience.

    “Continued monitoring of our clinical and radiographic results in this cohort is warranted so we can continue to learn and grow in the care of our shoulder arthroplasty patients.”

    Disclosures

    Dr. Laughlin and Dr. Kilian have no disclosures relevant to this study. Dr. Szerlip has disclosed that he is a paid consultant for Integra Lifesciences and that he is a paid consultant for and receives research support from Wright Medical Technology. Dr. Morris has disclosed that he receives research support from and is a paid consultant for Tornier and that he is a paid consultant for Wright Medical Technology. Dr. Edwards has disclosed that he is a paid consultant and paid presenter for DJO Surgical; that he is a paid consultant for Smith & Nephew; that he receives royalties and research support from and is a paid presenter for Tornier and Wright Medical Technology; and that he receives royalties from Orthohelix and Shoulder Options.

    References

    1. Szerlip BW, Morris BJ, Laughlin MS, Kilian CM, Edwards TB. Clinical and radiographic outcomes after total shoulder arthroplasty with an anatomic press-fit short stem. J Shoulder Elbow Surg. 2018 Jan;27(1):10-16. doi: 10.1016/j.jse.2017.08.012. Epub 2017 Oct 9.
    2. Szerlip BW, Morris BJ, Laughlin MS, Kilian CM, Edwards TB.Clinical and Radiographic Outcomes After Total Shoulder Arthroplasty with an Anatomic Press-Fit Short-Stem (Paper 074). Presented at the 2018 Annual Meeting of the American Academy of Orthopaedic Surgeons, March 6-10, 2018, New Orleans, Louisiana.