Outcomes following Total Hip Arthroplasty for Femoral Head Osteonecrosis in Patients with History of Solid Organ Transplant

The role of Piezo1 in bone marrow stem cells in response to elevated intraosseous pressure on regulating osteogenesis and angiogenesis of steroid-induced osteonecrosis of the femoral head

Objectives

Steroid-induced osteonecrosis of the femoral head (SONFH) remains a significant global health issue, with an unclear pathogenesis. Elevated intraosseous pressure is considered a key initiating factor in SONFH development. Impaired osteogenesis and angiogenesis are believed to be critical in SONFH progression. Piezo1, a mechanosensitive cation channel, may sense changes in intraosseous pressure. In this study, we set out to explore the role of Piezo1 in SONFH and how to target Piezo1 to treat SONFH.

Methods

Femoral head tissue specimens were collected from patients with ONFH and femoral neck fracture. Histological staining, Western blotting, and RT-PCR analysis were conducted to investigate the relationship between elevated intraosseous pressure and SONFH in rat models. Immunofluorescence staining of femoral head tissues was performed to study the spatiotemporal relationship between elevated intraosseous pressure and angiogenesis, osteogenesis, and development of SONFH.

Results

In the early stages of SONFH, elevated intraosseous pressure increased angiogenesis and osteogenesis. However, as the pressure continued to rise, both processes were inhibited. Furthermore, Elevated intraosseous pressure activated the Piezo1 signaling pathway in bone marrow stem cells. Piezo1 activation led to increased intracellular calcium influx, thus enhancing osteogenesis and angiogenesis through CAM-NFAT1 signaling pathway.

Conclusion

In the early stages of SONFH, Piezo1 in BMSCs senses increased intraosseous pressure, promoting angiogenesis and osteogenesis. Targeting Piezo1 to promote the osteogenic and angiogenic potential of stem cells, which could curb further increases in pressure, contribute to early treatment of SONFH.

The translational potential of this article

Currently, many mechanisms of the impact of elevated intraosseous pressure on osteonecrosis of the femoral head are still in the basic theoretical research stage, and we hope to translate them into clinical applications as soon as possible. We discovered that targeting Piezo1 curb further increases in intraosseous pressure, alleviating the damaging effects of glucocorticoids on stem cells and blood vessels, which exerting great significance in treatment of early stage SONFH.

Total Hip Arthroplasty Outcomes before or after Renal Transplant: A Retrospective Large Cohort Analysis

Background

While it is known that patients with end-stage renal disease (ESRD) are at an increased risk of complications following total hip arthroplasty (THA), there is a gap in the literature in comparing patients with ESRD to patients who undergo renal transplant (RT) before or after THA. This study is to address this gap by analyzing outcomes of THA in ESRD patients, RT patients, and RT candidates.

Methods

Using the PearlDiver Mariner database, ESRD patients, RT patients, and RT candidates undergoing primary THA were identified and compared. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. Ninety-day emergency department (ED) visits and inpatient readmission were also documented.

Results

A total of 7,868 patients were included: 5,092 had ESRD, 2,520 had RT before THA, and 256 were candidates for RT. Compared to patients with ESRD, RT patients demonstrated lower rates of medical complications such as pneumonia (3.61% vs. 5.99%, p = 0.039) and transfusion (4.60% vs. 7.66%, p < 0.001). Additionally, RT patients displayed decreased rates of surgical complications, including wound complications (2.70% vs. 4.22%, p = 0.001), periprosthetic joint infection (PJI) at 1 year (2.30% vs. 4.81%, p < 0.001) and 2 years (2.58% vs. 5.42%, p < 0.001), and aseptic loosening at 2 years (0.79% vs. 1.43%, p = 0.006). Similarly, when compared to RT candidates, RT patients demonstrated a lower incidence of postoperative complications, including 1-year PJI (2.30% vs. 5.08%, p = 0.013), 2-year PJI (2.58% vs. 5.08%, p = 0.028), 1-year aseptic loosening (0.56% vs. 2.73%, p < 0.001), and 2-year aseptic loosening (0.79% vs. 2.73%, p = 0.005). RT patients also had lower rates of ED visits and hospital readmissions.

Conclusions

Compared to ESRD patients and RT candidates, patients with RT have a significantly lower likelihood of medical complications, PJI, aseptic hardware loosening, ED visits, and hospital readmission. Patients with ESRD on the RT waiting list should delay THA until after RT surgery. For those not eligible for RT, it is vital to take extra precautions to reduce the risk of complications.

Hip, knee, and shoulder arthroplasty in patients with a history of solid organ transplant: A review

Solid organ transplants (SOT) have evolved into life-saving interventions for end-stage diseases affecting vital organs. Advances in transplantation techniques, donor selection, and immunosuppressive therapies have enhanced outcomes, leading to a growing demand for SOT. Patients with a solid organ transplant are living long enough to develop the same pathologies which are indicated for joint replacement surgery in the general population. SOT patients who undergo a total hip, knee, or shoulder arthroplasty do similarly in the context of clinical outcomes and implant survival when compared to the general population. These immunosuppressed patients tend to have higher complication rates in the short-term following surgery. Prudent management of these patients in the short-term may be necessary, but patients can expect to do well otherwise.

Defining Clinically Meaningful Subgroups for Risk Stratification in Patients Undergoing Revision Total Hip Arthroplasty: A Combined Unsupervised and Supervised Machine Learning Approach

BACKGROUND

Studies developing predictive models from large datasets to risk-stratify patients under going revision total hip arthroplasties (rTHAs) are limited. We used machine learning (ML) to stratify patients undergoing rTHA into risk-based subgroups.

METHODS

We retrospectively identified 7,425 patients who underwent rTHA from a national database. An unsupervised random forest algorithm was used to partition patients into high-risk and low-risk strata based on similarities in rates of mortality, reoperation, and 25 other postoperative complications. A risk calculator was produced using a supervised ML algorithm to identify high-risk patients based on preoperative parameters.

RESULTS

There were 3,135 and 4,290 patients identified in the high-risk and low-risk subgroups, respectively. Each group significantly differed by rate of 30-day mortalities, unplanned reoperations/readmissions, routine discharges, and hospital lengths of stay (P < .05). An Extreme Gradient Boosting algorithm identified preoperative platelets < 200, hematocrit > 35 or < 20, increasing age, albumin < 3, international normalized ratio > 2, body mass index > 35, American Society of Anesthesia class ≥ 3, blood urea nitrogen > 50 or < 30, creatinine > 1.5, diagnosis of hypertension or coagulopathy, and revision for periprosthetic fracture and infection as predictors of high risk.

CONCLUSION

Clinically meaningful risk strata in patients undergoing rTHA were identified using an ML clustering approach. Preoperative labs, demographics, and surgical indications have the greatest impact on differentiating high versus low risk.

LEVEL OF EVIDENCE

III.

Total joint arthroplasty following solid organ transplants: complications and mid-term outcomes

PURPOSE

Survival after solid organ transplant (SOT) is improving, and demand for total joint arthroplasty (TJA) among SOT recipients is rising. Outcomes including revision, periprosthetic joint infection, and survivorship based on SOT type are variable. We sought to compare peri-operative complications, implant survivorship, and mortality for patients undergoing TJA following SOT.

METHODS

A retrospective review of the institutional database for primary TJA among SOT recipients from 2000 to 2020 was performed. Revisions, conversion TJA, and patients with multiple organ transplants were excluded. Patients were stratified by transplant organ. Transfusions, 90-day readmissions and emergency department (ED) visits, revisions, and mortality were compared using descriptive statistics and Cox proportional hazard ratios.

RESULTS

A total of 119 total hip arthroplasties (THA) and 63 total knee arthroplasties (TKA) in SOT recipients were studied. Most common SOT was renal (39%), then lung (27%), liver (24%), and heart (10%). TKA postoperative transfusion rates varied by organ (p = 0.037; [heart 0%, liver 9.5%, renal 24.0%, lung 50.0%]). Implant survivorship was 95.6% at one year (95% CI 90.3-98.1) and 92.1% at four years (83.9-96.3). Mortality was 2.9% at one year (95% CI 1.1-7.4) and 23.2% at four years (95% CI 16.1-32.3). After adjusting for procedure, duration from transplant to TJA, age, and Elixhauser Index, lung recipients had higher mortality versus heart (RR 4.39 [95% CI 1.64-15.38]; p = 0.002), kidney (7.98 [3.04-24.61]; p < 0.001), and liver (7.98 [3.04-24.61; p < 0.001) patients.

CONCLUSION

TJA after SOT yields acceptable peri-operative outcomes and implant survivorship, but mortality risk is substantial, especially among lung transplant recipients.