Minimum 5-year follow-up for primary THA using a tapered, proximally coated cementless stem

Quantification of trunnion damage in a series of intact total hip arthroplasty femoral stems previously identified to be at risk of catastrophic failure

BACKGROUND

Corrosion at the head-neck junction of femoral stems is a rare complication of total hip arthroplasty (THA) with manifestations ranging from subclinical wear to failure. Prior studies have identified a single femoral component design with an increased propensity for catastrophic trunnion failure. The purpose of the present study was to quantify trunnion damage of this femoral component retrieved from patients undergoing revision THA for non-trunnionosis indications.

METHODS

24 femoral components from a single manufacturer were identified for study inclusion. Each prosthesis underwent stereomicroscopic inspection. Corrosion and fretting scores were assigned per the Goldberg criteria to quadrants of the trunnion. Material loss was calculated based on cone angles across trunnion quadrants. This was carried out using a coordinate measuring machine that digitised each trunnion surface. Stems were compared to a series of femoral stems with the same trunnion design.

RESULTS

20 of the 24 (83%) trunnions demonstrated corrosion, all 24 trunnions demonstrated fretting. Corrosion scores did not statistically differ with respect to trunnion zone (p = 0.53), while fretting scores were higher in the inferior compared to the superior zones (p < 0.001). There was no significant difference in cone angles assessing material loss between stems (p = 0.25).

CONCLUSIONS

Evidence of trunnion damage was observed in each stem retrieved for non-trunnionosis revision. Fretting occurred more frequently about the inferior quadrants. However, digitised trunnion shapes were similar between compared stems exhibiting no material loss. Therefore, it is possible that previous reports of trunnion failures for this implant are not a systemic issue, and that further investigation is required.

Incidence and Predictors of Subsidence Using Modular, Tapered, Fluted Titanium Femoral Stems in Aseptic Revision Total Hip Arthroplasty

BACKGROUND

Tapered, fluted titanium (TFT) femoral stems have become the gold standard in revision total hip arthroplasty (rTHA). However, there is a paucity of data on TFT stem subsidence rates following aseptic rTHA. Subsidence can lead to instability, mechanical failure, leg-length discrepancy, and may require revision surgery. This study evaluated the incidences and predictors of TFT subsidence in aseptic rTHA.

METHODS

A total of 102 TFT femoral stems of 4 designs were retrospectively reviewed. Stem subsidence was measured on digital radiographs taken immediately after surgery and at standard clinical follow-up. Patient characteristics, risk factors for subsidence, revision etiologies, and implant characteristics were recorded. Patient-reported outcome measures were also evaluated for a subset of cases.

RESULTS

Overall, 12% of stems subsided >1 cm, and subsidence was minimal (<3 mm) in ≥64% of cases. From immediate postoperative to 1-month radiographic follow-up, 79% of stems subsided a mean of 2.9 mm (range, 0.1 to 12 mm). Beyond 1 month, subsidence was minimal for ≥77% of cases. In multivariate analyses, women and less femoral implant canal fill were associated with greater subsidence (P ≤ .034). The TFT stem design was not associated with early subsidence (P = .816). There were no modular junction fractures. There were 2 fractures and 2 subsidence-related revisions for aseptic loosening that occurred postoperatively.

CONCLUSIONS

The amount of subsidence in TFT stems was low and was detectable in the early (less than 1 year) postoperative period. Maximizing TFT stem fill within the femoral canal appears to reduce the risk of subsidence without increasing femoral fracture rates and should be the goal with implantation of these devices.

LEVEL OF EVIDENCE

IV-Case Series, No Control Group.

Inadequate Metadiaphyseal Fill of a Modern Taper-Wedge Stem Increases Subsidence and Risk of Aseptic Loosening: Technique and Distal Canal Fill Matter!

BACKGROUND

Adequate interference fit and mechanical stability through optimal surgical technique are essential to prevent subsidence and loosening in cementless total hip arthroplasty. The purpose of this study is to determine the effect of surgical technique on radiographic subsidence and subsequent stability of a modern taper-wedge cementless stem.

METHODS

A retrospective review of 250 consecutive cementless primary total hip arthroplasties performed by 2 surgeons was completed. Surgeon A vigorously broached, maximizing the mediolateral stem dimension and confirmed final broach stability with a torsional test, whereas Surgeon B did not. All patients received identical taper-wedge stems. Preoperative bone morphology (canal flare index), postoperative subsidence, and canal fill were radiographically assessed.

RESULTS

Canal flare index was not different between groups (P = .747). There was significantly less subsidence at 1 month for Surgeon A (0.3 vs 1.3 mm, P < .001). Additional subsidence at 1 year occurred in only 0.8% of Surgeon A (1/119) compared to 51.6% of Surgeon B stems (33/64, P < .001). Surgeon technique and canal fill measured at 60 mm below the lesser trochanter were the only variables predictive for subsidence, where Surgeon A and B had a mean canal fill of 95% and 86%, respectively. Surgeon B had 2 cases of aseptic loosening (2%) at 2 and 3 years postoperatively.

CONCLUSION

These observations support that maximizing mediolateral canal fill and avoiding under-sizing the femoral implant with meticulous broaching technique minimizes subsidence and optimizes stability of modern cementless taper-wedge stems. Failure to optimize canal fill with appropriate broaching and surgical technique may predispose femoral components to failure from aseptic loosening.

The Accolade TMZF stem fulfils the demands of modern stem design: Minimum 5-year survival in a cohort of 937 patients

PURPOSE

Modern hip stem design includes a prosthesis that has a predictable outcome in all total hip arthroplasty (THA) patients, regardless of approach, surgeon or patient characteristics. Introduction without a learning curve and, in cases of problems, the possibility for a simple revision are other prerequisites. The purpose of this study is to evaluate whether the Accolade TMZF stem (Stryker Orthopedics, Mahwah, New Jersey, USA) is suitable to fulfil these demands. We report our mid-term survival of the Accolade TMZF hip stem in all patients from the first implantation at our institute.

METHODS

From the start of using the Accolade TMZF stem (March 2009) until February 2011, 937 THA were performed by 12 surgeons using a posterolateral or anterolateral approach. Survival of the stem was calculated using Kaplan-Meier analysis. Effect of approach, patient age and comorbidity were analysed with a Cox proportional hazards' model. The learning effect was determined by comparing the number of revisions in the surgeons' first 20 THAs with their next 30 THAs and the subsequent THAs.

RESULTS

At 5 years, cumulative stem survival was 97.9% based on revisions for all reasons and 98.8% with aseptic loosening as endpoint. We found no effect of surgical approach, patient age or comorbidity on stem survival. No learning effect was found.

CONCLUSION

The Accolade TMZF stem fulfilled the demands of modern stem design.

Clinical Performance of Ultra-Short Anatomic Cementless Versus Fourth-Generation Cemented Femoral Stems for Hip Replacement in Octogenarians

The aim of this study was to determine how ultra-short anatomic cementless vs cemented femoral stems affect the survival of primary total hip arthroplasties in octogenarians. Specifically, the authors investigated whether ultra-short anatomic cementless and cemented femoral components would have similar (1) functional results, (2) radiographic results, (3) revision and survival rates, and (4) complication rates in octogenarians. The authors evaluated 93 consecutive octogenarians (98 hips) in the ultra-short stem group (mean age, 86.5±5.3 years) and 78 consecutive octogenarians (92 hips) in the cemented stem group (mean age, 85.7±5.8 years). The average follow-up was 8.1 years (range, 5-12 years) in the ultra-short anatomic cementless stem group and 7.8 years (range, 5-11 years) in the cemented stem group. Mean preoperative (39 vs 37 points) and postoperative (81 vs 83 points) Harris hip scores were similar in the 2 groups (P=.131 and .128, respectively). The incidence of thigh pain was 0% in both groups. At final follow-up, mean Western Ontario and McMaster Universities Osteoarthritis Index scores (18 vs 14 points) and University of California, Los Angeles activity scores (4.3 vs 4.5 points) were similar in the 2 groups. The revision rate was 3% (3 hips) in the ultra-short stem group and 3% (3 hips) in the cemented stem group. Survivorship of the femoral stem was 97.3% at 8.1 years in the ultra-short stem group and 97.9% at 7.8 years in the cemented stem group (P=.136). Ultra-short anatomic cementless and cemented stems obtained rigid fixation in octogenarians. However, the incidence of undisplaced periprosthetic calcar fracture intraoperatively was significantly higher (P=.003) in the cemented stem group. [Orthopedics. 2018; 41(4):e470-e478.].

The Association Between Readmission and Patient Experience in a Total Hip Arthroplasty Population

BACKGROUND

Our goal was to determine whether readmissions within 30 or 90 days following discharge are associated with Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores for total hip arthroplasty (THA) patients.

METHODS

HCAHPS surveys from all patients who underwent THA between January 2016 and September 2016 in our institution were analyzed. Readmissions, demographics, baseline joint pain, joint function, and Veterans RAND-12 scores were collected. Statistical analyses involved Pearson's chi-squared tests for categorical variables and Student's t-tests for continuous variables. Multivariable logistic regression models were used to determine whether 30-day or 90-day readmissions were independently associated with HCAHPS scores.

RESULTS

A total of 1868 patients were identified, the survey was sent to 969 patients and 578 completed the survey (59.6%). Eight patients (1.4%) were readmitted within 30 days, and 28 patients (4.8%) within 90 days. These patients were more likely to undergo revision THA (P < .001). For the 30-day readmission cohort, 4 of 8 patients (50.0%) rated the hospital a 9 or 10 out of 10 compared to 466 of 567 patients (82.2%) of the non-readmitted cohort (P = .019). Thirty-day readmissions were associated with significantly lower likelihood of rating the hospital a 9 or 10 out of 10 (odds ratio 0.18).

CONCLUSIONS

Our results demonstrate a significant negative association between readmission and HCAHPS scores under several dimensions of the survey including nurse communication, doctor communication, pain management, and global satisfaction with the hospital experience.

Ultra-Short Versus Conventional Uncemented Stems for Hip Replacement in Octogenarians

The aim of this study was to determine how an ultra-short anatomic uncemented stem vs a diaphyseal filling five-eighths porous coated uncemented femoral stem (conventional stem) affects the survival of primary total hip arthroplasties in octogenarians. The current study consisted of 52 patients (55 hips) in the ultra-short stem group (mean age, 85.5±5.3 years) and 61 patients (72 hips) in the diaphyseal (conventional) stem group (mean age, 84.1±4.8 years). The predominant diagnosis was osteoarthritis, followed by osteonecrosis of the femoral head, in both groups. Average follow-up was 6.1 years (range, 5-8 years) in the ultra-short stem group and 6.3 years (range, 5-9 years) in the conventional stem group. Pre- (41 vs 39 points) and postoperative (85 vs 86 points) Harris hip scores were similar between groups (P=.131 and .129, respectively). The incidence of thigh pain was 0% (0 of 52 patients) in the ultra-short stem group and 15% (9 of 61 patients) in the conventional stem group. The revision rate was 1.8% (1 hip) in the ultra-short stem group and 1.4% (1 hip) in the conventional stem group. Survivorship of the femoral stem was 98.2% in the ultra-short stem group at 6.1 years and 98.6% in the conventional stem group at 6.3 years. Ultra-short anatomic and diaphyseal filling uncemented stems obtained osseointegration in all hips. However, the prevalence of thigh pain and periprosthetic fracture were significantly higher in the patients with a conventional stem than in those with an ultra-short stem. [Orthopedics. 2018; 41(1):28-34.].

Cementless Tapered Wedge Femoral Stems Decrease Subsidence in Obese Patients Compared to Traditional Fit-and-Fill Stems

BACKGROUND

Femoral component stability and resistance to subsidence is critical for osseointegration and clinical success in cementless total hip arthroplasty. The purpose of this study was to radiographically evaluate the anatomic fit and subsidence of 2 different proximally tapered, porous-coated modern cementless femoral component designs.

METHODS

A retrospective cohort study of 126 consecutive cementless total hip arthroplasties was performed. Traditional fit-and-fill stems were implanted in the first 61 hips with the remaining 65 receiving morphometric tapered wedge stems. Preoperative bone morphology was radiographically assessed by the canal flare index. Canal fill in the coronal plane, subsidence, and the sagittal alignment of stems was measured digitally on immediate and 1-month postoperative radiographs.

RESULTS

Demographics and canal flare indices were similar between groups. The percentage of femoral canal fill was greater in the tapered wedge compared to the fit-and-fill stem (P = .001). There was significantly less subsidence in the tapered wedge design (0.3 mm) compared to the fit-and-fill design (1.1 mm) (P = .001). Subsidence significantly increased as body mass index (BMI) increased in the fit-and-fill stems, a finding not observed in the tapered wedge design (P = .013).

CONCLUSION

An anatomically designed morphometric tapered wedge femoral stem demonstrated greater axial stability and decreased subsidence with increasing BMI than a traditional fit-and-fill stem. The resistance to subsidence, irrespective of BMI, is likely due to the inherent axial stability of a tapered wedge design and may be the optimal stem design for obese patients.

Cementless Tapered Femoral Stems for Total Hip Arthroplasty in Octogenarians

BACKGROUND

The use of cementless femoral components has become the standard in younger patients due to increased implant survivorship and decreased loosening. However, it remains controversial whether these femoral stems can provide comparable results in elderly patients. Therefore, our purpose was to compare the (1) incidence of revisions; (2) clinical outcomes; (3) incidence of postoperative blood transfusions; and (4) differences in complications between the 2 cohorts.

METHODS

Seventy-four consecutive patients (78 hips) aged 80 years or older, who underwent primary total hip arthroplasty using a cementless, tapered, femoral stem were retrospectively compared with a matched cohort of 76 patients (78 hips) who were less than 80 years. Mean age was 83 years (range, 80-91 years) vs 59 years (range, 17-79 years) for the matched group. Minimum follow-up was 2 years. Revision rates, clinical outcomes using the Harris Hip Score, incidences of complications, and postoperative transfusion rates were evaluated.

RESULTS

In the octogenarian cohort, the aseptic survivorship was 99%, compared with 95% in the matched group. There were 2 aseptic loosenings (2.6%): 1 femoral implant loosening (1.3%) and 1 acetabular loosening, but only 1 revision was performed, as one of the patients declined revision surgery. In the matched cohort, there were 6 revisions (7.7%). There were no significant differences in revision rates between the 2 cohorts, and no significant differences in final Harris Hip Score scores. The incidence of blood transfusion in the study group was 42% vs 19% in control group (P < .01).

CONCLUSION

The use of cementless, tapered, femoral stems yielded excellent results in the octogenarian group, although adequate patient preoperative optimization is necessary given the significantly higher transfusion incidence.

Are Range of Motion Measurements Needed When Calculating the Harris Hip Score?

BACKGROUND

Often the patient-reported outcome (PRO) component of the Harris Hip Score (HHS) is completed, but the physician-assessed range of motion (ROM) component is not. The PRO component only is called a modified Harris Hip Score (mHHS). The purpose of this study was to determine if a statistically significant or clinically meaningful difference existed when calculating the HHS with and without the physician-reported ROM portion.

METHODS

Included patients had complete HHS data (both physician and PRO components). Surgical procedure (primary or revision) was recorded for each subject. American Society of Anesthesiologists score was divided into low and high groups. Body mass index was divided into 4 categories. The study used a repeated measures design.

RESULTS

Data on 483 patients were collected between 12 and 60 months postoperatively (mean follow-up: 32.5 months, mean age: 55.9 ± 13.5 years). A mean difference of 4 points existed between the 2 groups: HHS group average score was 84.56 ± 13.18, and mHHS group average score was 88.74 ± 13.77. American Society of Anesthesiologists score, body mass index, and surgical type demonstrated a significant interaction with the HHS calculation method (P < .001). Primary total joint patients demonstrated a greater difference between the 2 scoring methods compared with revision patients.

CONCLUSION

No clinically meaningful difference in outcomes was found between the mHHS and the HHS. The calculation of the HHS is dependent on the inclusion of the ROM measurement. However, the small point difference between the HHS and mHHS indicates that the mHHS is still useful as an accurate determinant of patient clinical outcome, and ROM assessment is not essential.

Second-Generation Versus First-Generation Cementless Tapered Wedge Femoral Stems

Clinical outcomes of a new second-generation proximally coated, tapered wedge cementless stem were compared with those of its predecessor regarding (1) all-cause implant survivorship; (2) objective and subjective outcomes; (3) complications; and (4) radiographic features. Patients who underwent a primary total hip arthroplasty with the second-generation stem (68 hips) were compared with those who received the first-generation stem (136 hips) at a mean follow-up of 3.5 years. Although the first-generation stem was designed in the traditional manner, the second-generation stem was shortened to accommodate all surgical approaches and designed using a computed tomography scan-based database to enhance fit. The second-generation stem had survivorship, functional, and subjective outcomes similar to those of the first-generation stem.