Uncemented Stem Research Articles

Bone mineral density 10 years after a Zweymller uncemented stem prosthesis

The effect of a Zweymuller uncemented stem prosthesis on the long-term bone remodelling of femoral bone was examined using dual-energy X-ray absorptiometry (DEXA). Thirty-two patients (11 males, 21...

Cementless Stem for Femoral Neck Fractures in a Patient's 10th Decade of Life: High Rate of Periprosthetic Fractures.

Background:Subsidence of cementless femoral stems in hemiarthroplasty (HA) and increased fracture rates are ongoing concerns of orthopedic surgeons when treating fractures in very old patients. Additionally, bone cement implantation syndrome may result in perioperative cardiac or pulmonary complications, especially in older patients, leading to morbidity and mortality. This study was performed to analyze possible subsidence and intraoperative fractures in a cohort of very old patients treated with cementless stems.Methods:We retrospectively analyzed a consecutive cohort of patients aged ≥90 years with femoral neck fractures treated by uncemented HA and an anterior minimally invasive approach. Immediate full-weight bearing was allowed postoperatively. Pelvic radiographs were examined for subsidence immediately postoperatively and 6 weeks later.Results:We treated 109 patients (74% women; mean age, 93 years; range, 90-102 years) by HA from January 2010 to March 2016. The 30-day mortality rate was 16%, and the morbidity rate was 47%. There were 11 (12%) intraoperative fractures: 8 (Vancouver B2) had to be addressed immediately during the primary operation, while 3 (1 Vancouver B1 and 2 Vancouver AG) were treated conservatively. One periprosthetic femoral fracture (Vancouver B1) was documented during follow-up. In 17 patients, subsidence of >2.0 mm (median, 3.9 mm; range, 2.5-9.0 mm) was documented.Conclusion:Early subsidence was low in this very old cohort treated with an uncemented stem and not showing a periprosthetic fracture. The risk of intraoperative periprosthetic fractures was high. The use of uncemented implants in osteoporotic bone continues to be an intervention with high risk and should only be performed by experienced surgeons.Level of Evidence:Level III, Therapeutic study.

Periprosthetic stress fracture around a well-fixed type 2B short uncemented stem.

Despite the theoretical advantages of uncemented short stems, postoperative thigh pain is still matter of concern and can be attributed to different causes. We report a peculiar case of a stress fracture around a short cementless stem with cervico-metaphyseal fixation in an otherwise healthy patient. We implanted a MiniHipTM stem in a 43 year-old male professional golf player for the treatment of primary osteoarthritis using a ceramic on ceramic bearing. Against medical advice, the patient started to play soccer at the 4th postoperative month and was completely asymptomatic to that extent; but at 8 months follow-up and without a history of trauma he started complaining about progressive hip pain. After ruling out infection and loosening, histological analysis from a bone biopsy confirmed the diagnosis of stress fracture. Although revision surgery was initially scheduled, pain started to decrease gradually with protected weight-bearing (crutches) and disappeared around the first postoperative year, remaining the patient asymptomatic at 2 and half years of follow-up, with radiographs depicting a healed fracture with a hypertrophic callus. We encourage surgeons to be aware of the existence of periprosthetic stress fractures as a source of thigh pain (sometimes intractable), and despite being infrequent, they should always be contemplated, providing that these cases can be managed conservatively with rest and limited weight-bearing. After this uncommon case, we suggest to align the stem in order to equally distribute loads onto the medial calcar and the lateral femoral cortical.

Vibro-acoustic and nonlinear analysis of cadavric femoral bone impaction in cavity preparations

Owing to an ageing population, the impact of unhealthy lifestyle, or simply congenital or gender specific issues (dysplasia), degenerative bone and joint disease (osteoarthritis) at the hip pose an increasing problem in many countries. Osteoarthritis is painful and causes mobility restrictions; amelioration is often only achieved by replacing the complete hip joint in a total hip arthroplasty (THA). Despite significant orthopaedic progress related to THA, the success of the surgical process relies heavily on the judgement, experience, skills and techniques used of the surgeon. One common way of implanting the stem into the femur is press fitting uncemented stem designs into a prepared cavity. By using a range of compaction broaches, which are impacted into the femur, the cavity for the implant is formed. However, the surgeon decides whether to change the size of the broach, how hard and fast it is impacted or when to stop the excavation process, merely based on acoustic, haptic or visual cues which are subjective. It is known that non-ideal cavity preparations increase the risk of peri-prosthetic fractures especially in elderly people. This study reports on a simulated hip replacement surgery on a cadaver and the analysis of impaction forces and the microphone signals during compaction. The recorded transient signals of impaction forces and acoustic pressures (≈ 80 μs - 2 ms) are statistically analysed for their trend, which shows increasing heteroscedasticity in the force-pressure relationship between broach sizes. Tikhonov regularisation, as inverse deconvolution technique, is applied to calculate the acoustic transfer functions from the acoustic responses and their mechanical impacts. The extracted spectra highlight that system characteristics altered during the cavity preparation process: in the high-frequency range the number of resonances increased with impacts and broach size. By applying nonlinear time series analysis the system dynamics increase in complexity and demand for a larger minimum embedding dimension. The growing number of resonances with similar level of the transfer function indicates a higher propensity to dissipate energy over sound; the change in embedding dimension indicates a decrease in linearity. The spectral changes as well as the altered dimension requirements indicate either an improved coupling between the bone and the broach or the onset of micro-fractures caused by growing stress levels within the bone.

Risk factors related to periprosthetic femoral fracture following hemiarthroplasty for displaced femoral neck fracture in aged patients

Objective To analyze the risk factors associated with periprosthetic femoral fracture following hemiarthroplasty (HA) for displaced femoral neck fracture in aged patients. Methods From January 2013 to June 2016, 120 patients over 80 years old were treated by HA for displaced femoral neck fractures. They were 45 males and 75 females, with an average age of 85.2 years (from 80 to 97 years). Their fractures were Garden type Ⅲ(72 cases) and Garden type Ⅳ(48 cases). The time from injury to op-eration averaged 5.1 days. The patients were divided into a fracture group and a non-fracture group according to the presence or absence of the periprosthetic fracture. The general data of the 2 groups were compared; multivariate logistic regression analyses were done to indentify the influencing factors associated with periprosthetic femoral fracture. Results The 120 patients obtained a mean follow-up of 26.1 months (from 13 to 48 months). Periprosthetic femoral fracture occurred in 11 cases, giving an overall incidence of 9.2% (11/120). Compared with the non-fracture group, the average age was significantly older, the inci-dence of past fractures was significantly higher, significantly more types of uncemented stem were used, and American Society of Anesthesiologists (ASA) grading was significantly more severe for the fracture group (P 0.05). Multivariate Logistic regression analyses revealed that age [OR=1.268, 95%CI (1.059, 1.517), P=0.010] and type of uncemented stem [OR=0.072, 95%CI (0.008, 0.625), P=0.017] were independent risk factors for periprosthetic fracture. Conclusions The incidence of periprosthetic femoral fracture in the elderly pa-tients may be high following HA for femoral neck fractures. Since age and uncemented stem may be independent risk factors for periprosthetic femoral fracture, surgeons should pay enough attention to them in clinic. Key words: Femoral neck fractures; Arthroplasty, replacement, hip; Periprosthetic fractures; Risk factors; Aged, 80 and over

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.].

Anchoring and resulting primary stability of a kinked compared to a straight uncemented femoral stem.

The number of revision hip arthroplasties being performed is growing and implantation of a cementless stem has become established as the gold standard. For producing a primary stability, the press-fit procedure is the method of choice, but also can be achieved by multiple-point impactions. Specific femoral stems should follow the anatomical shape and provide a more extensive anchorage. The objective of this study was to evaluate the type, localization of the impaction and resulting primary stability of two different femoral revision stem designs (kinked vs. straight) after implantation via an endofemoral approach in the case of more extensive defects of the proximal femur. Cementless stems of two different designs were implanted in synthetic femurs. The specimens were analyzed by CT and tested considering axial/torsional stiffness and migration resistance in a servohydraulic testing machine. The present data do not show any significant differences between the two endofemorally implanted conical stems in contact area or in biomechanics with regard to migration and axial or torsional stiffness, despite having different designs. The location, type and length of the stem anchorage are not only influenced by the kinked or straight design, but in particular also by the surgical approach. Also in the case of an extensive proximal bone defect, in the endofemoral approach, both a conical and a three-point anchorage occur. Here, the length of the conical anchorage determines the primary stability and should be at least 55mm.

Load transfer in the proximal femur and primary stability of a cemented and uncemented femoral stem: An experimental study on cadaver femurs

There are principally two fixation methods in total hip arthroplasty, cemented and uncemented. Both methods have in general good long-time survival. Studies comparing cemented and uncemented femoral stems indicate that the cemented stems perform somewhat better, at least in the elderly population. The aim of this study was to compare load transfer and the initial micromotion pattern for an uncemented and a cemented stem. A total of 12 human cadavers were tested in a hip simulator during single leg and stair climbing. Strain was measured on the proximal femur before and after implantation of the prostheses, and the values were presented as percentage of physiological strain. The micromovements between the stem and bone were measured and a total point motion was calculated. The results showed small statistically significant differences between the fixation methods, the largest difference being 8.1 percentage points. The uncemented stem had somewhat higher micromotion than the cemented stem, but less than 10 µm. Both stems thus had acceptable primary stability. The main finding of this study is the strain and micromotion pattern of a cemented and an uncemented stem of similar geometry is overall equal. There were small statistical significant differences between the two fixation methods regarding strain and micromotion levels. The differences are considered too small to be clinically relevant.

The Rate of Radial Head Prosthesis Removal or Revision: A Systematic Review and Meta-Analysis.

We conducted a meta-analysis and systematic review with the primary objective to determine the overall incidence of radial head prosthesis removal or revision. Our secondary objectives addressed the incidence of removal or revision based on the type of prosthesis fixation (cemented, uncemented smooth stem, uncemented press-fit), material (metal, Vitallium, titanium, pyrocarbon), and design (short vs long stem and monopolar vs bipolar), and the reasons for prosthetic removal or revision. We included 30 studies with a total of 1,017 patients out of whom 77 prostheses were removed and 45 prostheses were revised. The pooled rate of radial head prosthesis removal or revision was 10.0% (95% confidence interval, 7.3%-13.6%) with a mean follow-up of 38 months. Subgroup analysis showed that the incidence of removal/revision was lowest with the cemented fixation, longer-stem, Vitallium material, and bipolar prosthesis. More than half of the prostheses were removed/revised for excision of the heterotopic ossification (47%) and for the treatment of stiffness and limitation of motion (42%). Other reasons recorded were pain (19%), loosening (16%), overstuffing (13%), instability (12%), infection (8%), and prosthesis disassembly (4%). The current data show that the highest incidence of removal/revision occurred within 2 years after implantation. There was no major difference in the incidence of removal/revision among different designs and materials. Implant removal was often performed as part of a procedure to manage elbow stiffness and heterotopic ossification at the surgeon's preference, not necessarily because the implant was malfunctioning. It appears that most radial head arthroplasties have an acceptable and comparable mid-term longevity; however, it is unclear whether long-term longevity will differ between devices. Prognostic II.

Is a short stem suitable for patients with hip dysplasia? A report on technical problems encountered during femoral reconstruction.

A wide variety of stems have been used for the treatment of osteoarthritis secondary to advanced hip dysplasia. Since evidence for using short stems in dysplastic hips is limited, we planned to analyse the technical problems encountered when reconstructing the proximal femur of patients with osteoarthritis secondary to congenital dysplasia of the hip treated with total hip arthroplasty (THA) using a type 2B short stem. We prospectively analysed 17 patients (22 hips) treated with primary THA performed with a single-branded short uncemented stem with metaphyseal fixation (MiniHip™; Corin). We excluded cases in which other type of stems were used, or in which retrospective data was only available. Mean follow-up was 41.22 months (minimum 24). We analysed clinical outcome using the modified Harris Hip Score (mHHS) and pain using the visual analogue scale (VAS). Radiographs were examined in order to determine causes of complications and revision surgery. All patients showed statistically significant improvement when preoperative and postoperative values for mHHS (54.19 vs. 94.57; p = 0.0001) and for pain VAS (8.71 vs. 0.71; p = 0.0003) were compared. No cases of thigh pain, instability or infection were found. 1 case of acetabular cup loosening and 1 case of periprosthetic fracture were diagnosed at 8 months and 45 days, respectively. Overall survival was 84.7% at 5 years (CI 95%, 64.4-105.3) with revision for any reason as an end point. When stem performance was separately evaluated, it showed a survival rate of 100% at 5 years with revision for aseptic loosening as an end point. THA with a type 2B short stem for the treatment of dysplastic osteoarthritis showed very few technical intraoperative problems, being a useful alternative for femoral reconstruction.

Primary stability in total hip replacement: A biomechanical investigation.

Background:In total hip replacement (THR), it is essential to achieve a primary stability to guarantee good long-term results. A novel locking screw hip (LSH)-stem, anchored to the medial cortex of the proximal femur by 5 monocortical locking screws, was developed to overcome the shortcomings of uncemented press-fit and cemented straight stems while simultaneously achieving primary stability. The aim of this study was to investigate the biomechanical competence of the LSH-stem in comparison to an uncemented press-fit stem.Methods:Six pairs of embalmed human cadaveric femora from donors aged 68 to 84 years were assigned to 2 study groups (n = 6) with equal number of right and left bones. The specimens in each group and pair were implanted with either an uncemented press-fit stem or an LSH-stem and tested biomechanically under progressively increasing cyclic axial loading until catastrophic failure. Axial construct stiffness, failure load, and cycles to failure were detected and statistically evaluated at a level of significance P = .05.Results:Although the axial stiffness was comparable for both prosthesis types, the uncemented press-fit stem showed a significant lower stability in terms of failure load and cycles to failure in comparison to the LSH-stem, P = .04.Conclusion:Converting our results to percentage of bodyweight (BW) in an assumed adult patient of 80 kg shows that the LSH-stem achieves a primary stability allowing to carry average loads of up to 507% BW, whereas the uncemented press-fit stem carried average loads of up to 404% BW. We conclude that both stems achieve a primary stability strong enough to carry hip joint loads experienced in the immediate rehabilitation period after THR.

Midterm outcomes of titanium modular femoral necks in total hip arthroplasty.

Modular femoral necks present surgical and biomechanical advantages in total hip arthroplasty (THA), but their benefits remain controversial due to risks of corrosion and fracture at the additional junction. This study aimed to report 10-year survival and clinical outcomes of a titanium femoral stem with a titanium modular neck in consecutive series. The authors reviewed the records of 97 patients (99 THAs) using uncemented modular stem and ceramic-on-ceramic acetabular components. Patients were evaluated at minimum follow-up of 5 years using the Harris Hip Score (HHS) and Postel Merle-D'Aubigné score (PMA). Survival was calculated using the Kaplan-Meier (KM) method with any reoperation or revision as endpoint. From the original cohort, 14 patients died, 6 were lost to follow-up, and 5 had revision operations with exchange of the femoral stem. The KM survival at 10 years was 94.2% (CI, 86.5-97.5). Clinical assessment was performed on 67 of the 72 patients (69 of the 74 hips) presently living with their original THA components. At mean follow-up of 9.4±1.0 years (median, 10; range, 5-11), the HHS was 93.6±8.2 and the PMA score 17.0±1.6. The X-rays revealed no signs of adverse reactions or bone loss. The uncemented titanium hip stem with modular titanium neck provided a satisfactory 10-year survival and clinical outcomes. Neck modularity enabled restoration of patient-specific femoral offset and limb length thanks to five possible neck configurations, though greater follow up is required to confirm the long-term benefits and safety of this design concept.

Short-Term Results of Ultra-Short Anatomic vs Ultra-Short Non-Anatomic Proximal Loading Uncemented Femoral Stems

BackgroundQuestion arises as to whether rigid fixation of ultra-short anatomic or ultra-short non-anatomic proximal loading uncemented femoral stem can be obtained without diaphyseal stem fixation. The purpose of this study is to compare the short-term clinical results, radiographic results, revision and survival rates, and complication rates of ultra-short anatomic versus ultra-short non-anatomic uncemented femoral stems. MethodsThis study consisted of 50 patients (56 hips) in the ultra-short anatomic uncemented stem group (mean age 61.4 ± 14.7 years) and 50 patients (56 hips) in the ultra-short non-anatomic uncemented stem group (mean age 59.5 ± 15.2 years). The mean follow-up was 3.4 years (range 3-4) in the ultra-short anatomic stem group and 3.5 years (range 3-4) in the ultra-short non-anatomic stem group. ResultsAt the final follow-up, the mean Harris hip scores (92 vs 93 points), Western Ontario and McMaster Universities Osteoarthritis scores (16 vs 15 points), University of California at Los Angeles activity scores (6.5 vs 6.8 points), the incidence of thigh pain (0% vs 4%), revision rates (0% vs 4%), aseptic loosening rate (0% vs 2%), and complication rates (2% vs 4%) were not significantly different between 2 groups. ConclusionBoth ultra-short anatomic and ultra-short non-anatomic proximal loading uncemented femoral stems obtained rigid fixation without diaphyseal stem fixation in the short-term follow-up. This finding suggests that an ultra-short anatomic uncemented femoral stem can be replaced with an ultra-short non-anatomic uncemented stem to reduce inventory of the femoral stems, and consequently reduce manufacturing and delivery cost of these femoral stems.

Combined Intracapsular And Extracapsular Neck Of Femur Fractures Case Series, Literature Review And Management Recommendations

Concomitant ipsilateral intracapsular and extracapsular fractures of the femoral neck are rare injuries with only 14 cases described in the literature as single case reports. We present three cases that were successfully and uniquely treated by uncemented hip arthroplasties. Two patients underwent complex primary uncemented total hip replacements, and one patient underwent an uncemented bipolar fluted stem hemiarthroplasty. The level of bearing constraint varied between implants. After describing our cases we review the literature and make recommendations on the management of these injuries. We believe that these are significant injuries and best functional results can be achieved with an early diagnosis and patient-specific approach that can include a total hip replacement in appropriate cases.

Humeral bone resorption after anatomic shoulder arthroplasty using an uncemented stem

Bone resorption around the femoral stem after total hip arthroplasty is a well-known phenomenon. However, only a few studies have evaluated bone resorption after shoulder arthroplasty. This study investigated the prevalence of humeral bone resorption after different shoulder arthroplasty procedures. The study included 147 shoulders that underwent total shoulder arthroplasty (TSA) or humeral head replacement (HHR) with an uncemented humeral stem from November 2008 to May 2015 and were monitored for more than 1 year. The prevalence of humeral bone resorption and risk factors were investigated. The most advanced grade of bone resorption, grade 0, occurred in 21 shoulders (14.3%). Grade 1 bone resorption occurred in 10 (6.8%), grade 2 in 28 (19.0%), grade 3 in 61 (41.5%), and grade 4 in 27 (18.4%). High occurrence of bone absorption was observed in zones 1, 2, and 7. Grade 4 bone resorption did not occur in zones 3 and 5. HHR, on-growth type stem coating, and occupation ratio were significant independent risk factors for grade ≥3 bone resorption, whereas female sex and HHR were significant independent risk factors for grade 4. Bone resorption was observed in 126 shoulders (85.7%), and full-thickness cortical bone resorption occurred in 27 shoulders (18.4%). Bone resorption was frequently observed at the greater tuberosity, lateral diaphysis, and calcar region (zones 1, 2, and 7). Significant risk factors included female sex, HHR with rotator cuff reconstruction, on-growth type stem coating, and high occupation ratio of the implant.

K-Wire Technique for the Removal of Uncemented Femoral Stem in Revision THA

In this work, K wires were used for 5 patients undergoing revision total hip arthroplasty to remove well-fixed, uncemented femoral stem without osteotomy. The technique was successful and considered to be safer and more economic than osteotomy with shorter operative time and easier surgical set up.

Implant Survival After Minimally Invasive Anterior or Anterolateral Vs. Conventional Posterior or Direct Lateral Approach

Since 2008, there has been an increase in the use of minimally invasive surgery (MIS) through an anterior or anterolateral approach for total hip arthroplasty (THA) in Norway. We compared the MIS approaches with the conventional posterior and direct lateral approaches in terms of revision rates and risk of revision. On the basis of data in the Norwegian Arthroplasty Register, 21,860 THAs with an uncemented stem, performed between 2008 and 2013, were identified and included in the cohort. Of these THAs, 2,017 were done through an MIS anterior approach; 2,087, through an MIS anterolateral approach; 5,961, through a posterior approach; and 11,795, through a direct lateral approach. Follow-up ended on December 31, 2015. Two and 5-year survival rates were calculated using Kaplan-Meier survival analysis. Relative risk (RR) was calculated using Cox regression analysis, with adjustment for age, sex, primary diagnosis, American Society of Anesthesiologists (ASA) grade, femoral head size, cup fixation, type of articulation, and duration of surgery and using 6 revision end points based on cause: any cause, infection, dislocation, femoral fracture, aseptic loosening, and other/unknown cause. The median duration of follow-up was 4.3 years. There were no significant differences among the surgical approaches with regard to the 2 and 5-year survival rates or RR of revision due to any cause. The RR of revision due to infection was 0.53 (95% confidence interval [CI] = 0.36 to 0.80, p = 0.002) for the MIS anterior and anterolateral approaches and 0.57 (95% CI = 0.40 to 0.80, p = 0.001) for the posterior approach compared with the direct lateral approach. The RR of revision due to dislocation was 2.1 (95% CI = 1.5 to 3.1, p < 0.001) for the posterior approach compared with the direct lateral approach but no significant difference in risk was found when the MIS anterior and anterolateral approaches were compared with the direct lateral approach (RR = 0.71, 95% CI = 0.40 to 1.3, p = 0.25). The revision rates and risk of revision associated with the MIS anterior and anterolateral approaches were not increased compared with those of the conventional posterior and direct lateral approaches. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Total Hip Intraoperative Femur Fracture: Do the Design Enhancements of a Second-Generation Tapered-Wedge Stem Reduce the Incidence?

BackgroundIntraoperative femur fracture (IFF) is a well-known complication in primary uncemented total hip arthroplasty (THA). Variations in implant instrumentation design and operative technique may influence the risk of IFF. This study investigates IFF between a standard uncemented tapered-wedge femoral stem and its second-generation successor with the following design changes: size-specific medial curvature, proportional incremental stem growth, modest reduction in stem length, and distal lateral relief. MethodsA single experienced surgeon's patient database was retrospectively queried for IFF occurring during primary uncemented THA using a standard tapered-wedge femoral stem system or a second-generation stem. All procedures were performed using soft tissue preserving anatomic capsule repair and posterior approach. The primary outcome measure was IFF. A z-test of proportions was performed to determine significant difference between the 2 stems with respect to IFF. Patient demographics, Dorr classification, and implant characteristics were also examined. ResultsForty-one of 1510 patients (2.72%) who received a standard tapered-wedge femoral stem sustained an IFF, whereas 5 of 800 patients (0.63%) using the second-generation stem incurred an IFF. No other significant associations were found. ConclusionA standard tapered-wedge femoral stem instrumentation system resulted in greater than 4 times higher incidence of IFF than its second-generation successor used for primary uncemented THA. Identifying risk factors for IFF is necessary to facilitate implant system improvements and thus maximize patient outcomes.

Total hip arthroplasty after failed osteosynthesis of proximal femoral fractures: Revision and mortality of 80 patients.

Total hip arthroplasty (THA) after failed osteosynthesis for proximal femoral fractures is associated with higher revision rates, particularly for dislocation. The purpose of this study was to report our results with THA after failed osteosynthesis within a treatment period of 10 years. A retrospective cohort study including 80 consecutive patients was conducted. After a minimum follow-up of 1 year, we evaluated revision for any cause including dislocation, outcome, and mortality. We performed 48 THAs with standard components only and 32 THAs with revision implants. Routinely, a 36-mm femoral head was used, and trochanteric fixation was performed in one-third of the cases. Total revision rate for any cause was 21%, which included six infections, six periprosthetic fractures, and five hematomas. One hip dislocation was also treated. Treatment with uncemented revision stem revealed significantly higher number of revisions-compared to standard cemented or uncemented stem. The mortality rate after 1 year was 9%, and the mean Parker score at follow-up was 6.6 (range: 0-9). THA was associated with an increased surgical revision rate, but hip dislocation was documented only once. In most cases, a standard implant with a large 36-mm femoral head size was sufficient. Uncemented revision stem revealed significantly higher number of revisions-compared to standard cemented or uncemented stem. One-year mortality was lower than expected.

Stable migration pattern of an ultra-short anatomical uncemented hip stem: a prospective study with 2 years radiostereometric analysis follow-up.

Shorter, anatomically shaped and proximally loading stems have been developed to achieve better stress distribution and be more bone preserving. The purpose of this prospective study was to evaluate the migration pattern of the Proxima™ ultra-short uncemented stem using radiostereometric analysis (RSA), and to review the literature regarding the migration of short stemmed hip arthroplasty. 25 patients (28 hips) with hip osteoarthritis received a Proxima stem during total hip arthroplasty (THA). To measure stem migration, repeated RSA examinations were done during a 2 year follow up period. The patients were evaluated with the hip specific (HOOS) and the generic health (EQ5D) scores up to 1 year, and clinically for 6 years postoperatively. Almost all migration occurred within the first 3 months, with mean subsidence of 0.22 mm and varus rotation of 1.04°, being the primary effect variables. After the third postoperative month and up to the 2 year RSA follow up no further significant migration occurred. The outcome scores showed substantial improvement after 1 year. No revisions were performed or indicated for any stem after a mean clinical follow up of 72.1 months. Like many other uncemented stems, the Proxima showed early migration up to 3 months hereafter osseointegration seems to have occurred. The achieved stability and clinical outcomes indicate favorable early results for this stem in younger patients who have good bone quality and average BMI. We found, however, the surgical technique to be slightly more demanding compared to conventional stems owing to the unique implant design that necessitates specific adjusted femoral cutting and broaching procedures.