Periprosthetic fracture following arthroplasty for femoral neck fracture: is a cemented stem protective?

BACKGROUND: Periprosthetic femoral fractures (PFF) carry significant morbidity following arthroplasty for femoral neck fracture (FNF). This study assessed fracture complications following arthroplasty for FNF and the effect of cement fixation of the femoral component on intraoperative and post-operative PFF. METHODS: Between February 2014 and September 2021, 740 patients with a FNF who underwent arthroplasty were analyzed for demographics, surgical management, use of cement for fixation of the femoral component, and subsequent PFF. Variables were compared with Mann-Whitney or Chi-square as appropriate. Multivariate logistic regression was used to assess independent risk factors associated with intraoperative or post-operative PFF. RESULTS: There were 163 THAs (41% cemented) and 577 HAs (95% cemented). There were 28 PFFs (3.8%): 18 post-operative and 10 intraoperative. Fewer post-operative PFFs occurred with cemented stems (1.63% vs. 6.30%, p = 0.002). Mean time from surgery to presentation with post-operative PFF was 14 months (0-45 months). Mean follow-up time was 10.3 months (range: 0-75.7 months). In multivariate regression, use of cement and THA was independently associated with decreased post-operative PFF (cement: OR 0.112, 95% CI 0.036-0.352, p < 0.001 and THA: OR 0.249, 95% CI 0.064-0.961, p = 0.044). More intraoperative fractures occurred during THA (3.68% vs. 0.69%, p = 0.004) and non-cemented procedures (5.51% vs. 0.49%, p < 0.001). In multivariate regression, use of cement was protective against intraoperative fracture (OR 0.100, CI 0.017-0.571, p = 0.010). CONCLUSIONS: In patients with a FNF treated with arthroplasty, cementing the femoral component is associated with a lower risk of intraoperative and post-operative PFF. Choice of procedure may be based on patient factors and surgeon preference.

Cemented vs cementless stems for revision arthroplasties due to Vancouver B2 periprosthetic hip fracture.

PURPOSE: According to Vancouver classification, B2 type fractures are most often treated with removal of the loose stem and implantation of a long stem that bypasses the fracture site. However, there is a controversy about the stem fixation that should be used: cemented or cementless. Hence, this study aims to compare cemented and cementless stems in prosthetic revision due to Vancouver B2 (VB2) periprosthetic hip fracture. METHODS: A retrospective study was done including all the patients treated with stem exchange due to VB2 periprosthetic hip fracture in a tertiary hospital between 2015 and 2022. Patients were divided into two groups according to the stem fixation used: cemented or cementless. Functional outcomes, hospital stay, surgical time, complication rate, and mortality were compared between the two groups of patients. RESULTS: Of the 30 included patients, 13 (43.4%) were treated with cementless stems and 17 (56.7%) with cemented stems. There were no statistically significant differences in age, gender, anesthesia risk scale (ASA) or functional capacity prior to the intervention. Patients treated with cementless stems had a higher complication and reintervention rate than those treated with cemented stems: 62 and 45% versus 34 and 6% (p = 0.035; p = 0.010), respectively. Furthermore, in the group of cementless stems a higher proportion of non-union was found (53.8% vs. 17.6%; p = 0.037). Also, the hospital stay (33 vs. 24 days; p = 0.037) and the time to full weight-bearing (21 days vs. 9 days; p < 0.001) were longer in the cementless stem group. CONCLUSION: Cemented fixation in stem revision due to Vancouver B2 periprosthetic hip fracture could be an optimal option with faster recovery which could decrease the rate of complications and reintervention, without compromising the fracture healing and patient mortality. Thus, this option can be considered when an anatomical reduction can be obtained, especially in elderly patients with multiple comorbidities in which a less aggressive surgical option should be considered.

Excellent Survival Rate of Cemented Modular Stems in One-Stage Revision for Periprosthetic Hip Infections With Massive Femoral Bone Loss: A Retrospective Single-Center Analysis of 150 Cases.

BACKGROUND: With the increasing incidence of total hip arthroplasty (THA), there is also an expected concurrent increase in revision THA (rTHA), which is known to have a high complication and re-revision rate. In the setting of infection, radical debridement is essential and options for femoral bone loss are limited. One viable solution is cemented modular stems, but limited evidence exists on their use in septic revision. This study aimed to analyze survival and complication related to the use of cemented modular stems in one-stage septic rTHA with severe femoral bone loss. METHODS: The institutional database of patients who underwent rTHA for septic one-stage revision with cemented modular stems was reviewed. Exclusion criteria were patients aged less than 18 years and nonseptic or 2 stage revisions. Outcomes measured were complication, re-infection, re-operation, and survivorship of the implant. A total of 150 patients were included. The mean age was 68 years (range, 30 to 91), and the mean follow-up was 105 months (range, 1 to 150). RESULTS: Treatment was considered successful in 81.3% of cases. Patients who underwent multiple prior surgeries demonstrated a lower rate of treatment success (P < .001). The main cause of failure was re-infection (11 of 28). Among cases failed for aseptic reasons (17 of 28), loosening of the cemented modular stem was the cause of re-revision in 2 patients (1.3%). CONCLUSIONS: The use of modular cemented stems is a viable option in case of septic one-stage rTHA associated with severe femoral bone loss. However, surgeons and patients should be aware that this treatment is still characterized by a high rate of complications, which may lead to further surgeries. LEVEL OF EVIDENCE: III.

Total hip arthroplasty with femoral shortening osteotomy using polished cemented stem vs. modular cementless stem in patients with Crowe type IV developmental dysplasia of the hip.

INTRODUCTION: There is still little information regarding the advantages of a using a polished tapered stem for Crowe Type IV developmental dysplasia of the hip (DDH). This study aimed to investigate the mid-term clinical and radiological outcomes of primary total hip arthroplasty (THA) with femoral shortening osteotomy using modular and polished tapered stems and to compare the results between the modular and polished tapered stems. MATERIALS AND METHODS: This retrospective review included 32 patients (37 hips) with Crowe type IV DDH who underwent primary THA with femoral shortening osteotomy using a modular stem (cementless group, 14 hips) or a polished tapered stem (cement group, 23 hips) between 1996 and 2018. Clinical data and radiographic assessments were reviewed to analyze the differences between the two groups. RESULTS: The mean duration of patient follow-up of the cementless group (134.4 months) was longer than that of the cement group (75.5 months). There were no differences in clinical results, time of bone union, and survival rate between the two groups. However, the cementless group exhibited a higher ratio of intraoperative fracture and thinning of cortical bone including stress shielding, medullary changes, stem alignment changes, and osteolysis, compared to the cement group. CONCLUSIONS: The findings of this study suggest that THA with femoral shortening osteotomy using both cemented and modular stems can provide satisfactory results. However, considering the occurrence of intraoperative fracture and radiographic analysis in the current study, the cement stem may have an advantage for patients with bone fragility and deterioration in bone quality.

Revision Total Knee Arthroplasty Utilizing Threaded Pins in Cement for Tibial Bone Loss.

Introduction: a primary goal in revision total knee arthroplasty is to recreate and restore near-normal knee biomechanics by reapproximating the native anatomy. Tibial bone loss poses a challenge for surgeons. Bone cement, bone allograft, screws-in-cement, metaphyseal sleeves or cones, and metallic augments are some options for addressing bony deficiency, with endoprosthetic proximal tibia replacement a consideration for the most severe cases. Case Description: we present a case for the novel use of threaded Steinmann pins augmented with cement to reconstruct a massive tibial metaphyseal cortical defect during revision knee arthroplasty. A 76-year-old male presented with an infected primary total knee arthroplasty using MSIS (Musculoskeletal Infection Society) criteria and underwent a standard two-stage revision total knee arthroplasty once the knee was confirmed sterile. Intraoperatively, significant posteromedial and metaphyseal tibial bone loss was identified. In order to avoid proximal tibial replacement and the extensor mechanism complications seen with these, coupled with obligate gastrocnemius flap, a metaphyseal cone was utilized in the proximal tibia with four vertical threaded Steinmann pins spaced approximately 1 cm apart at its periphery, subsequently cut flush with the level of the cone after cementation to recreate the tibial cortex. The patient's function and range of motion continue to improve with no evidence of structural complication at 2.5 years of follow-up. Discussion: the implementation of threaded Steinmann pins was utilized in this case to stabilize a cemented metaphyseal cone in the revision of an infected total knee with significant tibial bone loss. The threaded property may help prevent migration of these pins in comparison to smooth pins. Creation of a stable platform in a revision total knee arthroplasty poses a substantial challenge in the context of significant bone loss, and our case depicts a good short-term outcome and another option for surgeons to consider before moving toward endoprostheses.

Cement Mantle Quality and Stem Alignment in Cemented Collarless Polished Tapered Stems Implanted via the Direct Anterior and Direct Lateral Approaches: A Single Institution Experience.

BACKGROUND: The aim of this study was to compare the stem alignment and the quality of cement mantle of collarless polished tapered cemented stems inserted through the direct anterior approach (DAA) and the direct lateral approach (DLA). METHODS: A comparative retrospective study of 232 hybrid total hip arthroplasties using a cemented collarless polished tapered stem through either the DAA (n = 147) or DLA (n = 85) was performed. Radiographic evaluation included stem alignment, cement mantle quality, and cement mantle thickness. RESULTS: On anteroposterior radiographs, stems implanted through the DLA were more likely to be in neutral alignment, than those implanted through the DAA (83.5%[n = 71] versus 71.4% [n = 105]; P = <.001). No difference between approaches was noted for stem alignment on lateral radiographs or cement mantle quality. Multivariate analysis revealed factors associated with suboptimal cement mantle and included Dorr type B or C femur as well as male gender. A mean cement mantle thickness ≥2mm was achieved in all Gruen zones for both approaches. CONCLUSION: In our series, the DAA was associated with a higher incidence of coronal plane stem malalignment compared to the DLA when using cemented tapered polished femoral components for total hip arthroplasty. No difference in lateral stem alignment or cement mantle quality was found.

Long-term survival of fully cemented stem in re-revision total knee arthroplasty performed on femur with diaphyseal deformation due to implant loosening.

PURPOSE: The study aims to analyze long-term clinical and radiographic results, and survival of re-revision total knee arthroplasty (TKA) using fully cemented stems performed on femurs with diaphyseal deformation. METHODS: Thirty-seven re-revision TKAs using fully cemented stems performed in femoral diaphyseal deformations, characterized as diaphyseal canal enlargement and cortex deformation due to aseptic loosening of previously implanted stems, between 2003 and 2015 were retrospectively reviewed. The mean follow-up period was 10.0 years. Clinically, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were evaluated. Radiographically, mechanical axis (MA) and component positions were measured. Complications and survival rates were also analyzed. RESULTS: Clinically, the WOMAC significantly improved at final follow-up (61.2 vs 47.2, p < 0.001), but not the ROM (95.5 vs 102.5, p = 0.206). Radiographically, the MA and component positions were appropriate, with no changes in component positions from immediately post-operative to final follow-up, but with MA change from varus 2.9° to 3.7° (p = 0.020). Two cases (5.4%) with history of previous infections developed periprosthetic joint infection (PJI). Debridement with polyethylene insert exchange following antibiotic suppression were performed in those cases because of concern for difficult implant-cement removal. The five and ten year survival rates were 100% and 93.2%, respectively. CONCLUSION: Fully cemented stems are viable in providing long-term satisfactory survival after re-revision TKA in patients with femoral diaphyseal deformation. However, it should be used carefully for those with previous infections.

The Effects of Rasp Oversize on the Clinical and Radiographic Outcomes of Total Hip Arthroplasty With a Collared Satin-Finished Composite Beam Cemented Stem.

BACKGROUND: This study aimed to compare the clinical and radiographic outcomes of using two different oversized rasps in total hip arthroplasty (THA) with a composite beam cemented stem (DCM-J). METHODS: A consecutive series of 105 hips underwent hybrid THA using the DCM-J stem between 2006 and 2010. Among the patients with a minimum 10-year follow-up, a 1.5-mm oversized rasp was used in 38 hips (group S), whereas a 0.5-mm oversized rasp was used in 36 hips (group M). The Japanese Orthopedic Association hip score and radiographic findings were evaluated, including cement mantle thickness, stress shielding, and cortical hypertrophy. RESULTS: The Japanese Orthopedic Association hip score was significantly improved postoperatively with 100% of the implant survival rate in both groups when septic loosening was excluded. Radiographic assessment performed immediately postoperatively revealed that the cement mantle thickness was significantly larger in group M than group S in Gruen zone 1 but did not differ between groups in zones 2-7. Stress shielding was significantly more frequent in group M than group S at 2 years (P = .011), 5 years (P = .012), and ≥10 years postoperatively (P = .038). Cortical hypertrophy appeared in a time-dependent manner; however, the prevalence did not significantly differ between groups at final follow-up at a mean of 11.7 years (range 10-14 years) postoperatively. CONCLUSIONS: The DCM-J stem achieved good clinical results in both groups. Stress shielding was significantly more frequent in THA using the 0.5-mm rasp than the 1.5-mm rasp, indicating that sufficient cement mantle room should be prepared for the cemented stem.

Biomechanical Comparison of Periprosthetic Femoral Fracture Risk in Three Femoral Components in a Sawbone Model.

BACKGROUND: The increasing use of orthopedic total hip arthroplasty implants has led to a consequent rise in the incidence of associated periprosthetic fractures (PPFs). Analysis of the National Joint Registry data showed the choice of cemented hip stem influenced the risk of a PPF occurring. However, the effect of implant design in relation to the risk of PPFs has not been investigated. METHODS: The main objective is to compare the biomechanics of PPFs as a failure of the Exeter V40, CPT, and DePuy C-Stem stems in a composite Sawbone model to identify whether a difference in the risk of fracture exists between them. Twenty-six Sawbones were divided into 3 groups, cemented with the Stryker Exeter, Zimmer CPT, or DePuy C-Stem and then torqued to fracture. RESULTS: When compared with the Exeter, the CPT- and C-Stem-implanted Sawbone models would sustain PPFs at a statistically significantly lower rotation to failure (20.1° and 26.7° vs 33.6°, P < .01) and torque to failure (124 Nm and 143 Nm vs 174 Nm, P < .01) values. The energy release rate at failure for the Exeter was significantly higher than that for the CPT and C-Stem (61.2 Nm vs 21.8 Nm and 38.6 Nm, P < .01), which led to more comminution. CONCLUSION: The CPT- and C-Stem-implanted femurs, although fracturing earlier, fractured in a simple pattern with less comminution. The differences in stem design mean higher stress at the critical point of failure in the CPT implanted femur compared with the Exeter and DePuy, which is likely the reason behind the observed increased risk of PPFs with the CPT implant.

Periprosthetic Femoral Fracture Is a Leading Cause of Early Revision With Taper-Slip Stems in Primary Total Hip Arthroplasty: An Analysis of 2765 Total Hip Arthroplasties From a High-Volume Hospital.

BACKGROUND: In 2016, the CPT stem replaced the Exeter stem as the main cemented stem at our institution. We assessed the prevalence of revision for periprosthetic femoral fracture (PFF) in patients operated on with either CPT or Exeter stem and compared the risk for revision between these stems. METHODS: Primary total hip arthroplasties either performed in 2012-2015 with Exeter stem (n = 1443) or in 2017-2018 with CPT stem (n = 1322) were included. The prevalence of revision for PFF was compared. The Kaplan-Meier estimated survivorships were calculated for the 2 stem designs. The risk for revision was analyzed using the Cox proportional hazard regression model. RESULTS: At 2 years, PFF was the most common reason for revision in the study population (1.3% prevalence, comprising 35% of all revisions). Moreover, 1.6% (95% confidence interval [CI] 1.0-2.4) of the CPT and 1.0% (95% CI 0.6-1.6) of the Exeter stems had been revised due to PFF. The 3-year Kaplan-Meier probability estimates for all-cause revision were 4.8% for the CPT (95% CI 3.6-6.0) and 3.3% for the Exeter stem (95% CI 2.3-4.3). The hazard ratio for revision due to any reason was 1.1 (95% CI 0.3-3.8) during the first 2 weeks, and 1.8 (95% CI 1.2-2.7, P = .006) from 2 weeks onwards for the CPT compared with the Exeter stem. CONCLUSION: The considerable number of PFF revisions with taper-slip stems, especially with CPT stems, is a matter of concern. Alternative cemented stems should be considered in patients at high risk for PFF.

Trabecular Metal Cones Combined With Short Cemented Stem Allow Favorable Outcomes in Aseptic Revision Total Knee Arthroplasty.

BACKGROUND: The purpose of this study was to compare the functional outcomes and implant survivorship at a minimum of 5 years of follow-up of several reconstruction techniques with or without metaphyseal cone and stems of variable length. METHODS: A retrospective comparative matched analysis was performed from 2 prospectively collected databases. Only patients who underwent revision total knee arthroplasty procedures for aseptic causes using a single design of rotating hinge knee with a minimum of 5 years of follow-up were analyzed. Patients were separated into 3 groups: trabecular metal (TM) cones + short cemented stems (TM + short stem [SS]), TM cones + long uncemented stems (TM + long stem [LS]), and no cone (NC) + long uncemented stems (NC + LS). A matching process based on age (±5 years) was realized. RESULTS: About 99 patients were included; 33 in the TM + SS group, 33 in the TM + LS group, and 33 in the NC + LS group. The mean time of follow-up was 9.3 years. A significant difference of the improvement of subscale pain, symptom, activities of daily living, quality of life of the Knee Injury and Osteoarthritis Outcome score and knee, function of the Knee Society Score was observed in favor of TM + SS group compared with the 2 other groups. At 8 years of survivorship, the components free of revision for any cause were 90.9% for the TM + SS group, 84.9% for the TM + LS group, and 90.6% for the NC + LS group. CONCLUSION: The use of a short cemented tibial stem combined with a TM cone in revision total knee arthroplasty offers identical survival rate with better functional outcome compared with the use of a long uncemented stem associated with TM cones or metallic augments at a minimum of 5 years of follow-up.

Hybrid stems are superior to cemented stems in revision total knee arthroplasty: a systematic review and meta-analysis of recent comparative studies.

INTRODUCTION: The demand for revision total knee arthroplasty (TKA) has grown significantly in recent years. The two major fixation methods for stems in revision TKA include cemented and 'hybrid' fixation. We explore the optimal fixation method using data from recent, well-designed comparative studies. METHODS: We performed a systematic review of comparative studies published within the last 10 years with a minimum follow-up of 24 months. To allow for missing data, a random-effects meta-analysis of all available cases was performed. The odds ratio (OR) for the relevant outcome was calculated with 95% confidence intervals. The effects of small studies were analyzed using a funnel plot, and asymmetry was assessed using Egger's test. The primary outcome measure was all-cause failure. Secondary outcome measures included all-cause revision, aseptic revision and radiographic failure. RESULTS: There was a significantly lower failure rate for hybrid stems when compared to cemented stems (p = 0.006) (OR 0.61, 95% CI 0.42-0.87). Heterogeneity was 4.3% and insignificant (p = 0.39). There was a trend toward superior hybrid performance for all other outcome measures including all-cause re-revision, aseptic re-revision and radiographic failure. CONCLUSION: Recent evidence suggests a significantly lower failure rate for hybrid stems in revision TKA. There is also a trend favoring the use of hybrid stems for all outcome variables assessed in this study. This is the first time a significant difference in outcome has been demonstrated through systematic review of these two modes of stem fixation. We therefore recommend the use, where possible, of hybrid stems in revision TKA.

A simple angle-measuring instrument for measuring cemented stem anteversion during total hip arthroplasty.

BACKGROUND: During total hip arthroplasty (THA), the accurate placement of the femoral components is an important determinant of the success of the procedure. This study assessed the accuracy of cemented stem placement using a new angle-measuring instrument. The primary objective was to investigate the accuracy of the intraoperative measurements of cemented stem anteversion obtained using the angle-measuring instrument. Our secondary objective was to evaluate the accuracy of stem positioning performed using the angle-measuring instrument. METHODS: We compared the intraoperative stem anteversion measurements obtained using the angle-measuring instrument with postoperative stem anteversion measurements obtained using computed tomography in 149 hips (measurement accuracy). We also compared the target angle and postoperative stem anteversion in 105 hips (implantation accuracy). RESULTS: The mean amount of intraoperative stem anteversion was 37.9° ± 10.1°, and the mean amount of postoperative stem anteversion was 37.0° ± 10.4°. The mean measurement accuracy was 0.9° ± 6.1°, and the absolute measurement accuracy was 4.9° ± 3.7°. The correlation coefficient for the relationship between the intraoperative and postoperative stem anteversion measurements was 0.824 (p = 0.000). The mean amount of target angle was 37.4° ± 7.6°, and the mean amount of postoperative stem anteversion was 35.9° ± 9.1°. The mean implantation accuracy was 1.4° ± 5.6°, and the mean absolute implantation accuracy was 4.3° ± 3.6°. The correlation coefficient for the relationship between the target angle and postoperative stem anteversion was 0.795 (p = 0.000). CONCLUSIONS: The angle-measuring instrument measured intraoperative stem anteversion accurately, and cemented stem was implanted accurately during THA with the angle-measuring instrument.

The Long-Term Results of Total Hip Arthroplasty With a Cemented ß-Titanium Stem.

BACKGROUND: We report on the outcomes of a double-tapered cemented stem made of ß-titanium alloys (Ti-15Mo-5Zr-3Al) at least 10 years after total hip arthroplasty. METHODS: We retrospectively analyzed 148 consecutive, primary total hip arthroplasties using this stem performed in 130 patients between January 2004 and August 2008. The patients' mean age was 59.6 years (range, 24-79). Implant survival was evaluated using Kaplan-Meier curves with the primary end point being stem revision for any reason and the secondary end point being stem revision for aseptic stem loosening. We also clinically and radiologically followed 140 hips (in 123 patients) for an average of 12.2 years (range, 10-15). RESULTS: The only revisions were for 2 stems with deep infection. Ten-year survival was 99.3% (95% confidence interval, 95.4%-99.9%) and 100% for the primary and secondary end point, respectively. The mean Japanese Orthopaedic Association hip score improved from 51.4 preoperatively to 88.7 at the last follow-up. Radiolucent lines at the stem-cement interface were seen in 14 hips (10.0%). None of the hips met the criteria of radiological stem loosening. Nineteen stems (13.6%) subsided by around 1 mm between 2 and 8 years after surgery. Distal femoral cortical hypertrophy occurred in 24 hips (17.0%), mostly with valgus alignment. CONCLUSION: The clinical outcomes of the femoral stems were excellent with survival at 10 years. Stem subsidence and distal femoral cortical hypertrophy did not affect the results. Long-term use of ß-titanium alloy stems is safe and effective.

High Incidence of Intraoperative Fractures With a Specific Cemented Stem Following Intracapsular Displaced Hip Fracture.

BACKGROUND: To reduce costs of orthopedic implants, the government decided to standardize implants used across different specialties in a group of hospitals located in the same geographic area. The usual cemented stem used in the context of intracapsular displaced geriatric hip fractures was replaced by another stem. Abnormal intraoperative calcar and trochanteric fractures were noted. The purpose of this study is to determine the incidence of intraoperative periprosthetic fractures following an intracapsular displaced hip fracture treated with this specific cemented stem compared to the previous implant. METHODS: This is a retrospective cohort study comparing an historic cohort of hip fractures treated with the OmniFit EON (Stryker, Kalamazoo, MI) cemented stem with a new cohort of patients who received the Corail (DePuy Synthes, Warsaw, IN) cemented stem. Four orthopedic surgeons reviewed operative reports and postoperative radiographs. RESULTS: The treatment group included 348 patients who received the Corail stem. The control group included 77 patients. The 2 groups had similar baseline characteristics (P > .05) except for the presence of dementia. Incidence of intraoperative calcar or greater trochanteric fracture was 15.5% for the Corail group and 2.7% for the control group (P < .05). No patient-related factors or surgeon-related factors were related to a higher number of fractures in the treatment group (P > .05). CONCLUSION: The Corail cemented stem presents an abnormal number of iatrogenic intraoperative fractures following displaced femoral neck fracture in our geriatric population. No external factor seems to explain this high number of fractures. Implant design should be questioned. LEVEL OF EVIDENCE: III.

Postoperative migration of the anatomical and functional anteversion angle following total hip arthroplasty with a well-fixed cemented femoral component with line-to-line implantation.

INTRODUCTION: Little is known about the association between well-fixed polished tapered cemented stems (PTCS) implanted by the line-to-line technique and changes of stem migration, or the change of functional anteversion of the femur after total hip arthroplasty (THA). MATERIALS AND METHODS: This retrospective study included 422 two-stage bilateral primary THAs performed using PTCS implanted by the line-to-line technique. CT scans were made on both the target side (first postoperative CT) and on the contralateral side (second postoperative CT) 1 week postoperatively. The mean follow-up was 7.8 months. CT data for each scan were transferred to 3D template software (Zed hip, Lexi, Japan). The postoperative changes of anatomical stem anteversion (ASA), functional femoral anteversion (FFA), and stem subsidence were evaluated. RESULTS: A total of 20 THAs with CT scans were available on 3D template software. The ASA and the FFA had migrated - 0.68° ± 0.62° and - 5.5° ± 9.7°, respectively, over the follow-up period. A significant positive correlation was observed between the change of subsidence and ASA (r2 = 0.34, p = 0.007), between the FFA on the second postoperative CT and ASA on the first postoperative CT (r2 = 0.26, p = 0.02) and between the FFA on the second postoperative CT and FFA on the first postoperative CT (r2 = 0.52, p = 0.0003). CONCLUSION: This study indicates that the change in axial rotation of a PTCS implanted by the line-to-line technique was less than that reported by other studies and the preoperative external rotation contracture was substantially improved after THA.

Effects of cemented versus press-fit primary humeral stem fixation in the setting of revision shoulder arthroplasty.

BACKGROUND: The influence of primary humeral stem fixation method (cemented or press fit) on intraoperative or postoperative outcomes in the setting of revision shoulder arthroplasty is unknown. METHODS: A retrospective analysis of a prospectively collected cohort of revision shoulder arthroplasty patients from a single tertiary center was performed. Demographic variables, intraoperative data, and 90-day complication rates were compared between cemented and press-fit primary stem fixation cohorts. Follow-up radiographs were graded and compared using a modified Gruen system for humeral lucencies. RESULTS: Eighty-six primary shoulder replacements (34 hemiarthroplasties, 39 anatomic total shoulder arthroplasties, 13 reverse total shoulder arthroplasties) underwent revision arthroplasty with humeral stem removal between 2004 and 2017. Forty-five patients had cemented primary humeral fixation and 41 had press-fit fixation. The cemented cohort was older than the cementless cohort (66.6 vs. 61.4 years; P = .03) but otherwise demonstrated no difference in gender, body mass index, type of primary prosthesis (hemi, total, or reverse), or time between primary and revision operations. The cemented and cementless cohorts showed similar rates of humeral osteotomy (28.9% vs. 29.3%; P = .97), operative time (133.5 vs. 121.3 minutes; P = .16), and 90-day complication rates (13.3% vs. 9.8%; P = .61). Cemented vs. press-fit primary stems also had similar rates of humeral lucencies seen on follow-up radiographs after revision (77.1% vs. 60.6%; P = .14). CONCLUSION: Humeral stem fixation with or without cement during primary shoulder arthroplasty demonstrated similar operative time, need for intraoperative humeral osteotomy, and postoperative complication rates in the setting of revision arthroplasty.

Long-term survival of the cemented Müller CDH stem: a minimum follow-up of 10 years.

INTRODUCTION: Total hip arthroplasty in patients with altered anatomy of the hip and femur, such as in congenital dysplasia of the hip, is challenging and often requires specially designed stems. Müller straight stems have shown excellent long-term results; however, long-term data on the analogous cemented Müller CDH stem are still missing. The aim of this study was to analyze long-term survival, identify potential risk factors for aseptic loosening, and analyze radiological outcome of the cemented Müller CDH stems. MATERIALS AND METHODS: Between 01/1985 and 06/2005, 95 Müller CDH stems (Zimmer, Winterthur, Switzerland) made up of 3 different materials were cemented using 2 different bone cements: 38 of stainless steel/high-viscosity cement, 31 of a cobalt-chrome-based alloy (CoCr)/low-viscosity cement, and 26 of a titanium-based alloy (Ti)/low-viscosity cement. All patients had a prospective clinical and radiological follow-up according to the standards of our institution. The cumulative incidence for revision of the stem was calculated using a competing risk model. To identify demographic and implant-related risk factors for aseptic loosening of the stem, a multivariate regression model for competing risks was performed. RESULTS: The cumulative risk of revision at 15 years was 12.5% (95% CI 6.6-20.5%) for aseptic loosening of the stem as endpoint, with marked differences for the various stem materials used: stainless steel 2.7% (0.2-12.3%), CoCr 12.9% (4.0-27.3%), and Ti 24.5% (9.6-43.1%). Regression modeling revealed that Ti stems in combination with low-viscosity cement (HR 10.2) and implantation with an axis deviation greater than 3° (HR 3.8) are risk factors for aseptic loosening. CONCLUSIONS: Long-term survival of the cemented Müller CDH stem is comparable to other Müller-type straight stems and uncemented implants. Similar to the original Ti Müller straight stem, the Ti Müller CDH stem also showed an increased risk for aseptic loosening and should, therefore, no longer be used.

Effect of Stem Size and Fixation Method on Mechanical Failure After Revision Total Knee Arthroplasty.

BACKGROUND: Although the need for stemmed components is well accepted to improve mechanical survival in revision total knee arthroplasty (TKA), the ideal fixation method and stem design remain controversial. METHODS: We performed a retrospective review of 223 patients who underwent revision TKA in whom stemmed components had not been used previously and with a mean follow-up of 61.6 months, including 108 components with fully cemented stems and 316 components with "hybrid" press-fit stems. RESULTS: Based on a time to event model, risk for mechanical failure was equivalent for both cemented and hybrid stems (relative risk, 0.991; P = .98). Young age was the single greatest risk factor for mechanical failure (P = .006). Although there was a trend toward increased failure with cemented stems in patients aged <65 years, there was no significant difference in risk after accounting for covariates (relative risk, 1.4; P = .50). Intramedullary canal fill, not stem length or diameter, was the strongest predictor of failure with hybrid stems, and risk was reduced by 41.2% for each additional 10% canal fill. CONCLUSION: In conclusion, both cemented and hybrid modular stems are viable options in revision TKA. Surgeons should attempt to maximize canal filling of hybrid stems to obtain a solid press-fit. In addition, further studies are needed to evaluate the long-term survival of cemented stem fixation in young patients.

Clinical significance of corrosion of cemented femoral stems in metal-on-metal hips: a retrieval study.

PURPOSE: The clinical significance of corrosion of cemented femoral stems is unclear. The purpose of this retrieval study was to: (1) report on corrosion at the stem-cement interface and (2) correlate these findings with clinical data. METHODS: We analysed cemented stems (n = 36) composed of cobalt-chromium (CoCr) and stainless steel (SS) in a series of revised metal-on-metal hips. We performed detailed inspection of each stem to assess the severity of corrosion at the stem-cement interface using a scale of 1 (low) to 5 (severe). We assessed the severity of corrosion at each stem trunnion and measured wear rates at the head taper and bearing surfaces. We used non-parametric tests to determine the significance of differences between the CoCr and SS stems in relation to: (1) pre-revision whole blood Co and Cr metal ion levels, (2) trunnion corrosion, (3) bearing surface wear and (4) taper material loss. RESULTS: The corrosion scores of CoCr stems were significantly greater than SS stems (p < 0.01). Virtually all stem trunnions in both alloy groups had minimal evidence of corrosion. The median pre-revision Co levels of implants with CoCr stems were significantly greater than the SS stems (p < 0.01). There was no significant difference in relation to pre-revision Cr levels (p = 0.521). There was no significant difference between the two stem types in relation to bearing wear (p = 0.926) or taper wear (p = 0.148). CONCLUSIONS: Severe corrosion of cemented femoral stems is a common finding at our retrieval centre; surgeons should consider corrosion of CoCr stems as a potential source of metal ions when revising a hip.