Cantilever Failure of Modular Uncemented Femoral Revision Stem in Patients with Poor Proximal Femoral Support; How to avoid it?

Objectives: Revision hip arthroplasty is a major surgical challenge and is even more difficult in cases with a deficient proximal femur. Modular uncemented cone body revision femoral stems were introduced as a solution. They have the advantage of optimising joint kinematics by allowing the variable degrees of version, offset and leg length. However, we noticed cantilever failure of such stems, particularly in patients with deficient proximal femoral support. Fatigue fracture of the revision femoral stems should raise questions about its use in patients with insufficient proximal femoral bone support. Methods: We present a case series of five patients with the cantilever failure of Stryker restoration modular stem conical distal femur prosthesis. These cases were identified during a retrospective review of revision hip surgeries performed at our trust. Results: The stem failed after an average of 22.6 months post-revision surgery. Primarily, poor proximal femur bone support with a well-fixed distal stem and secondarily high BMI led to this catastrophic failure in the absence of trauma. All five cases were re-revised to Stanmore proximal femoral replacement and achieved good functional outcomes after an average follow-up of seven years. Conclusion: Proximal femoral bone support should be restored to prevent early cantilever failure of distally fixed proximal modular revision femoral stems. Consider a proximal femoral replacement if we cannot ensure proximal bone support.

Risk factors for femoral stem fracture following total hip arthroplasty: a systematic review and meta analysis.

BACKGROUND: Femoral stem fracture following total hip arthroplasty (THA) is an infrequent but nevertheless devastating complication, with an increasing worldwide prevalence as demand for primary THA continues to increase. The aim of this study was to perform a systematic review and meta-analysis of risk factors for femoral stem fracture to help identify at risk patients. METHODS: A systematic search was conducted on EMBASE, MEDLINE and AMED to identify relevant studies. Data regarding study design, source, population, intervention, and outcomes was collated. Data extraction was performed on a custom form generated using Cochrane recommended methodology and analysis of risk factors performed including odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: A total of 15 studies reporting a total of 402 stem fractures in 49 723 THAs were identified. The median time from index procedure to stem fracture was 68 months (IQR 42.5-118) whilst mean age at index surgery was 61.8 years (SD 6.9). Male gender (OR = 3.27, 95% CI = 2.59-4.13, p < 0.001), patient weight above 80 kg (OR = 3.55, 95% CI = 2.88-4.37, p < 0.001), age under 63 years (OR = 1.22, 95% CI = 1.01-1.49, p < 0.001), varus stem alignment (OR = 5.77, 95% CI = 3.83-8.7, p < 0.001), use of modular implants (OR = 1.95, 95% CI = 1.56-2.44, p < 0.01) and undergoing revision arthroplasty (OR = 3.33, 95% CI = 2.70-4.1, p < 0.001) were significant risk factors for prosthetic stem fracture. A risk window of 15 years post-surgery was identified. CONCLUSIONS: This review concludes that patient weight, younger age, male sex, varus stem alignment, revision arthroplasty and use of modular stems are significant risk factors for femoral stem fracture. Modifying these risk factors where possible may help reduce incidence of femoral stem fracture in at risk patients.

Retrospective survival analysis of the use of uncemented modular tapered stems for revision in periprosthetic Vancouver B-type fractures. Is instability a threat to survival?

INTRODUCTION AND OBJECTIVES: Periprosthetic hip fractures show increasing incidence and complexity, representing a challenge for the surgeon. We aimed to evaluate the survival of uncemented modular tapered stems in the treatment of periprosthetic Vancouver B2 and B3 type fractures and review the main complications and factors associated with decreased survival. MATERIALS AND METHODS: We performed a retrospective study of patients submitted to revision arthroplasty for treatment of periprosthetic femoral stem Vancouver B2 and B3 type fractures with an uncemented modular fluted tapered stem (MRP-Titan). Demographic and radiographic parameters were analyzed. The survival rate (free of reoperation) was calculated at 2- and 5-years using the Kaplan-Meier survivorship analysis. RESULTS: Thirty-nine patients were included with a mean age of 73.5 years and a mean follow-up of 5 years. Arthroplasty survivorship at 2 years was 73.7% and at 5 years was 67.5% (mean 8.4 years; range 6.7-10.2). Survivorship was inferior in the patients with episodes of instability (mean 2.5 years; range 0-5.42) (p<0.001). At least one episode of instability occurred in 26.3% of patients and 60% of these patients had a femoral head size 32mm or lower. At least one episode of instability occurred in 71.4% of patients with a greater trochanter fracture (p=0.008). The consolidation rate was 90.6% and the mortality rate was 23.7%. In the group of patients that died, 55.6% were submitted to at least one revision surgery (p=0.044). CONCLUSION: Survivorship of an uncemented modular stem (MRP-Titan) in revision for PHF is significantly reduced by episodes of instability.

A Consecutive Series of Vancouver B2 Periprosthetic Femur Fractures Treated With Contemporary Monoblock Versus Modular Revision Stems: Clinical and Radiographic Outcomes.

BACKGROUND: Tapered fluted titanium (TFT) stems are the implant design of choice for managing Vancouver B2 periprosthetic femur fractures (PFFs), producing reliable results over the past few decades. The aim of this study was to compare the radiographic and clinical outcomes of Vancouver B2 PFFs treated with contemporary monoblock versus modular TFTs. METHODS: A consecutive series of 113 patients (72 women, 64%, mean age 70 years [range, 26 to 96]) who had a B2 PFF were treated with either a monoblock (n = 42) or modular (n = 71) TFT stem between 2008 and 2021. The mean body mass index was 30 ± 7. The mean follow-up was 2.9 years. A radiographic review was performed to assess leg length and offset restoration, endosteal cortical contact length, and stem subsidence. Kaplan-Meier analyses were used to determine survivorship without revision, reoperation, or dislocation. RESULTS: There was no difference in the restoration of leg length (0.3 ± 8.0 mm) or offset (2.8 ± 8.2 mm) between the monoblock and modular cohorts (P > .05). Mean endosteal cortical contact length (47.2 ± 26.6 versus 46.7 ± 2 6.4 mm, P = .89) and stem subsidence (2.7 ± 3.5 versus 2.4 ± 3.2 mm, P = .66) did not differ. No difference in patient-reported outcome measures (Hip Disability and Osteoarthritis Outcome Score-Joint Replacement; Veterans RAND 12 Item Health Survey Physical and Mental; visual analog score; and Lower Extremity Activity Scale) between the groups was observed. Survivorship at 2 years free from reoperation, revision, and dislocation was 90.4, 90.3, and 97.6%, respectively, for the monoblock cohort; and 84.0, 86.9, and 90.0%, respectively, for the modular cohort. CONCLUSIONS: No significant differences in radiographic or clinical outcomes were observed between patients treated with monoblock or modular TFTs in this large series of B2 PFFs.

Last generation fluted modular titanium stem in revision hip arthroplasty: a narrative review of mid- and long-term outcomes.

Background and Objective: Tapered fluted titanium stems (TFTS), were introduced to overcome proximal femur bone defects. They obtain stable fixation even in catastrophic proximal bone loss. Modular ones have the advantage to adjust length, rotation, off-set independently from the distal module. Short-term publications have been showing favorable outcomes burdened by an unacceptably high rate of stem failure. Still, there is a paucity of mid- and long-term reports. This narrative review aims at analyzing recent literature on modular TFTS with at least 5 years of minimum follow-up to gain a better understanding of implant survival, performance, and complications. Methods: A search of the PubMed database was performed with selected key terms. Results were screened after the application of strict inclusion and exclusion criteria. Extracted data were subsequently evaluated to obtain an up-to-date overview of the results and complications of TFTS. Key Content and Findings: Modular TFTS showed a consistent increase in patient reported outcomes that persists at 10 years and above. Femoral fractures were the most common intraoperative complication. Despite modularity, dislocation still occurs at a variable rate (1.2-12%). With revision for any cause as an endpoint, overall survival approaches 83% after 10 years of follow-up. If femoral revision only is evaluated, excellent survival rates (>95%) have been published. Stem subsidence over 5 mm was reported in less than 5% of patients, only 1 requiring femoral revision. The mean incidence of stem mechanical failure was 3.39%, although most breakages occurred in stems eventually retired from the market. Conclusions: Satisfactory survival rates were observed, with an acceptable rate of complications. Stem mechanical failure, excluding those stems eventually retired from the market, remains a marginal event. Therefore, the use of modular TFTS in revision surgery is safe and effective even in the long term.

Mean 23-Year Outcomes of Total Hip Arthroplasty Using a Modular Femoral Stem With Metaphyseal Fixation Sleeve.

BACKGROUND: Although the modular sleeve concept for femoral implants has several advantages, studies reporting on greater than 20-year outcomes are limited. This study aimed to report the mean 23-year results of total hip arthroplasty (THA) using a modular stem with metaphyseal fixation sleeve. METHODS: This study reviewed primary THAs performed using a modular stem between October 1994 and April 1998. Of the 272 hips (221 patients) identified, 220 hips (177 patients) satisfying the minimum 20-year follow-up were included. The Harris Hip Score was used for clinical evaluation. Final hip radiographs were analyzed to evaluate the implant stability and the extent of femoral osteolysis. The mean follow-up duration was 23 years (range, 20 to 28). RESULTS: The mean Harris Hip Score improved from 38 points (range, 26 to 67) preoperatively to 90 points (range, 71 to 100) at the final follow-up (P < .001). Femoral osteolysis was observed in 146 hips (67.1%), but 145 were located proximal to the osseo-integrated sleeve. Overall, 4 femoral revisions were performed; 2 for chronic infection, one for aseptic loosening, and one for periprosthetic femoral fracture. Of the 19 (8.6%) periprosthetic femoral fractures, the most common type was Vancouver AG (13 hips). One (0.5%) asymptomatic distal stem fracture occurred, while no complications were identified at the stem-sleeve junction. Implant survivorship free of any femoral revision was 98.3% at 23 years. CONCLUSIONS: A THA using a modular stem with metaphyseal fixation sleeve demonstrated 98.3% stem survivorship with excellent clinical outcomes at a mean follow-up of 23 years in non-obese patients.

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.

The Early- to Mid-term Outcome of Novel Cementless Modular Femoral Stem in East Asian Patients.

Background: Early firm fixation of the femoral implant is crucial in total hip arthroplasty (THA) with unstable metaphysis or a large degree of femoral bone loss. This study aimed to evaluate the outcomes of THA using a novel cementless modular, fluted, tapered stem in such cases. Methods: From 2015 to 2020, 105 hips (101 patients) had surgery performed by two surgeons at two tertiary hospitals using a cementless modular, fluted, tapered stem for periprosthetic fractures, massive bone loss, prosthetic joint infection sequelae, or tumorous condition. Clinical outcomes, radiographic results, and survivorship of the implant were evaluated. Results: The average follow-up period was 2.8 years (range, 1-6.2 years). The Koval grade was 2.7 ± 1.7 preoperatively and maintained at 1.2 ± 0.8 at the latest follow-up. The plain radiograph showed bone ingrowth fixation in 89 hips (84.8%). The average stem subsidence at postoperative 1 year was 1.6 ± 3.2 mm (range, 0-11.0 mm). Five reoperations (4.8%) were needed, including 1 for acute periprosthetic fracture, 1 for recurrent dislocation, and 3 for chronic periprosthetic joint infection. Kaplan-Meier survivorship with reoperation for any reason as the endpoint was 94.1%. Conclusions: The early- to mid-term results of THA with the novel cementless modular, fluted, tapered THA stem system were satisfactory clinically and radiologically. The shortcomings inherent to its modularity were not identified. This modular femoral system may provide adequate fixation and be a practical option in the setting of complicated THA.

Does the Periprosthetic Fracture Pattern Depend on the Stem Fixation Method in Total Hip Arthroplasty?

Background: Management of periprosthetic femoral fractures (PFFs) is reportedly challenging. Different patterns of PFFs would occur based on whether stem fixation was primarily cemented or cementless and whether these patterns would be associated with clinical outcomes, such as subsidence, fracture union, and complications, after stem revision. Methods: A retrospective comparative study was performed, involving 52 PFF patients treated with tapered fluted modular stems (TFMSs). In the 52 patients with Vancouver B2 or B3, including 21 cemented stems and 31 cementless stems, fracture patterns and bone stock were analyzed. Clinical outcomes after revision surgery using the TFMSs were compared between the two groups. Results: Transverse or short oblique type PFFs occurred around the cemented stem with loosening at the bone-cement interface. The Paprosky type III femoral deficiency and Vancouver type B3 fracture were observed more frequently in the cemented stem group. Otherwise, spiral fractures occurred more frequently in the cementless group (p < 0.001). Excessive subsidence of > 5 mm was observed more frequently in the cemented stem group (p < 0.001). The re-revision rates were higher in the cemented group than in the cementless group (p = 0.047). Conclusions: In our study, it was found that the patterns of transverse or oblique PFFs were more frequently produced with cemented stems, while long spiral fractures were more frequent with cementless stems. Stem subsidence and reoperation related to complications were more common in patients with PFFs around cemented stems than those with PFFs around cementless stems.

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 Hip Arthroplasty Using a Modular, Cementless Femoral Stem: Long-Term Follow-Up.

BACKGROUND: As the number of primary total hip arthroplasty (THA) cases increase, so does the demand for revision operations. However, long-term follow-up data for revision THA is lacking. METHODS: A retrospective review was completed of patients who underwent revision THA at a single institution between January 2002 and October 2007 using a cementless modular stem. Patient demographic, clinical, and radiographic data was collected. Preoperative and postoperative patient-reported outcome scores were compared at a minimum of fourteen-year follow-up. RESULTS: Eighty-four patients (89 hips) with a median age of 69 years (range, 28 to 88) at operation were included. Indications for revision included aseptic loosening (84.2%), infection (12.4%), and periprosthetic fracture (3.4%). Twenty-two hips sustained at least 1 complication: intraoperative fracture (7.9%), dislocation (6.7%), prosthetic joint infection (4.5%), deep venous thrombosis (3.4%), and late periprosthetic fracture (2.2%). There were no modular junction complications. Eight patients underwent reoperations; only three involved the stem. Thirty-eight patients (45%) were deceased prior to final follow-up without known reoperations. Twenty-seven patients (32%) were lost to follow-up. Twenty-one patients (23%) were alive at minimum fourteen-year follow-up. Complete patient-reported outcomes were available for nineteen patients (range, 14 to 18.5 years of follow-up). Significant improvement was seen in UCLA activity, VR-12 physical, hip disability and osteoarthritis outcome score, joint replacement., and Harris Hip score pain and function scores. CONCLUSION: Challenges of long-term follow-up include patient migration, an unwillingness to travel for re-examination, medical comorbidities, advanced age, and death. The cementless modular revision stem demonstrated long-term clinical success and remains a safe and reliable option for complex revision operations.

Similarly low blood metal ion levels at 10-years follow-up of total hip arthroplasties with Oxinium, CoCrMo, and stainless steel femoral heads. Data from a randomized clinical trial.

The use of inert head materials such as ceramic heads has been proposed as a method of reducing wear and corrosion products from the articulating surfaces in total hip arthroplasty, as well as from the stem-head taper connection. The aim of the present study was to compare the blood metal ion levels in patients with Oxinium and CoCrMo modular femoral heads, as well as monoblock stainless steel Charnley prostheses at 10 years postoperatively. The 150 patients with osteoarthritis of the hip joint included in a randomized clinical trial were grouped according to femoral head material. One group (n = 30) had received the Charnley monoblock stainless steel stem (DePuy, UK). The other patients (n = 120) received a Spectron EF CoCrMo stem with either a 28 mm CoCrMo or Oxinium modular head (Smith & Nephew, USA). After 10 years, 38 patients had withdrawn, 19 deceased, 7 revised due to aseptic loosening and 5 revised due to infection. The 81 patients with median age of 79 years (70-91) were available for whole blood metal ion analysis. The levels of Co, Cr, Ni and Zr in the blood were generally low with all the head materials (medians <0.3 micrograms/L) and no statistical difference between the groups were found (p = .2-.8). Based on the low blood metal ion values in our study groups, no indication of severe trunnion corrosion in patients with CoCrMo heads was observed, neither was there any beneficial reduction in metal ion exposure with the Oxinium femoral heads.

Modular versus monoblock stem in revision total hip arthroplasty: a systematic review and meta-analysis.

Background: Total hip arthroplasty (THA) is estimated to grow in the following decades with a consequent increase of THA revisions (rTHA). This systematic review and meta-analysis aims to compare modular and monoblock stem in rTHA surgery, focusing on clinical and radiological outcomes and complication rates. Methods: A literature search was performed using the following search strategy: ((Modular stem) OR (monolithic stem)) AND (hip review) on PubMed, Scopus, and Cochrane. Randomized controlled trials (RCTs) and observational studies (OS) compared clinical and radiological outcomes, and complication rates for monoblock and modular revision femoral stem were included. The risk of bias was assessed through the Methodological Index for Non-Randomized Studies (MINORS) score. The Review Manager (RevMan) software was used for the meta-analysis. The rate of complications was assessed using odds ratio (OR) with 95% confidence intervals (CIs). Results: The authors included 11 OS and one RCT with 3,671 participants (mean age: 68.4 years old). The mean follow-up was 46.9 months. There was no prevalence of subsidence for one type of stem. Mean subsidence was from 0.92 to 10 mm for modular stem and from 1 to 15 mm for monoblock stem. Postoperative Harris Hip Score (HHS) showed better results with modular stems without statistical significance [mean difference (MD) =1.32; 95% CI: -1.62 to 4.27; P=0.38]. No statistically significant difference was found for dislocations (OR =2.48; 95% CI: 0.67 to 9.14; P=0.17), infections (OR =1.07; 95% CI: 0.51 to 2.23; P=0.86), intraoperative fractures (OR =1.62; 95% CI: 0.42 to 6.21; P=0.48), and postoperative fractures (OR =1.60; 95% CI: 0.55 to 4.64; P=0.39). Conclusions: Modular and monoblock stems show comparable and satisfactory clinical and radiological outcomes for rTHA. Both stems are valid and effective options for managing femoral bone deficit in hip revision surgery. The main limitation of this study is the small number and low quality of enclosed studies that compared the two stems. Moreover, the modular stem is usually used for more complex cases with lower quality femoral bone stock.

Comparison of radiographic vs. computed tomography canal filling ratio measurement of stems in revision knee prostheses.

Background: Lack of consensus on which measurement method gives the most accurate results for medullary canal filling ratio (CFR) of stems used in revision knee prostheses causes confusion when interpreting scientific studies. Therefore, the present study aims to find the most accurate measurement method of CFR on direct radiographs. Methods: Twenty-eight femoral and 27 tibial components of 29 patients with a mean age of 72.86 ± 6.32 years were included in the study. Two different methods were used for computerized tomography CFR measurement. These methods and five different radiographic measurement methods used for CFR were compared statistically. Results: There was no statistically significant difference between the real tomographic CFR of the femoral stem and the CFR calculation made by using ellipse area (p > 0.05). There was also no statistically significant difference between the tomographic CFR measurement calculated according to the largest stem size that can be implanted, and the method that accepted the smallest value as CFR after the measurement made according to Parsley's method on AP and lateral radiographs (p > 0.05). The results obtained by using all other tests were statistically different from each other. Conclusion: CFR calculation made by using ellipse area, is the most accurate method for femoral stem CFR. The method that accepted the smallest value as CFR after the measurement made according to Parsley's method on AP and lateral radiographs is the most accurate method for tibial stem CFR.

Long-Term Outcomes of Revision Total Hip Arthroplasty Using a Tapered and Fluted Modular Stem: A Mean Follow-Up of 16 Years.

BACKGROUND: Tapered modular stems are increasingly used in revision total hip arthroplasty (THA) with deficient femoral bone stock. This study aimed to report the long-term outcomes of revision THA using a tapered and fluted modular stem. METHODS: Between December 1998 and February 2006, 113 revision THAs (110 patients) were performed with a tapered and fluted modular stem at a single institution. Hip radiographs were used to identify stem subsidence, stability, and femoral radiolucency. Final outcomes were assessed in 72 hips (70 patients), with a minimum follow-up of 10 years. RESULTS: The mean follow-up duration was 16 years (range, 10-23). At the final evaluation, the Harris Hip Score improved from a mean of 41 points (range, 10-72) preoperatively to 83 points (range, 56-100) (P < .001). Six femoral re-revisions were performed for the following reasons: 1 aseptic loosening, 2 stem fractures, and 3 infections. One stem fracture occurred at the modular junction after 14 years, and the other at a more distal location after 15 years. Stem subsidence was >5 mm in 6 hips (9.1%), but secondary stability was achieved in all stems. Osseointegration was observed in 63 (95.5%) hips. Stem survivorship was 91.1% with an end point of any re-revision and 94.6% for aseptic re-revision. CONCLUSION: A tapered and fluted modular stem demonstrated excellent implant survivorship with reliable bony fixation at a mean follow-up of 16 years. This type of stem can be a durable option for revision THA in patients who have femoral defects.

Femoral revision with the direct anterior approach.

OBJECTIVE: The advantages of the direct anterior approach (DAA) in primary total hip arthroplasty as a minimally invasive, muscle-sparing, internervous approach are reported by many authors. Therefore, the DAA has become increasingly popular for primary total hip arthroplasty (THA) in recent years, and the number of surgeons using the DAA is steadily increasing. Thus, the question arises whether femoral revisions are possible through the same interval. INDICATIONS: Aseptic, septic femoral implant loosening, malalignment, periprosthetic joint infection or periprosthetic femoral fracture. CONTRAINDICATIONS: A draining sinus from another approach. SURGICAL TECHNIQUE: The incision for the primary DAA can be extended distally and proximally. If necessary, two releases can be performed to allow better exposure of the proximal femur. The DAA interval can be extended to the level of the anterior superior iliac spine (ASIS) in order to perform a tensor release. If needed, a release of the external rotators can be performed in addition. If a component cannot be explanted endofemorally, and a Wagner transfemoral osteotomy or an extended trochanteric osteotomy has to be performed, the skin incision needs to be extended distally to maintain access to the femoral diaphysis. POSTOPERATIVE MANAGEMENT: Depending on the indication for the femoral revision, ranging from partial weight bearing in cases of periprosthetic fractures to full weight bearing in cases of aseptic loosening. RESULTS: In all, 50 femoral revisions with a mean age of 65.7 years and a mean follow-up of 2.1 years were investigated. The femoral revision was endofemoral in 41 cases, while a transfemoral approach with a lazy­S extension was performed in 9 patients. The overall complication rate was 12% (6 complications); 3 patients or 6% of the included patients required reoperations. None of the implanted stems showed a varus or valgus position. There were no cases of mechanical loosening, stem fracture or subsidence. Median WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score before surgery improved significantly from preoperative (52.5) to postoperative (27.2).

A Modified Modular Stem in Primary Total Hip Arthroplasty for Developmental Dysplasia of the Hip: Average 11-year Follow-Up in Cases With Previously Reported 3-year Clinical Results.

BACKGROUND: Modular stems require careful follow-up, especially after any design modification. This study investigated the mid- to long-term outcomes of total hip arthroplasty in patients with developmental dysplasia of the hip using the S-ROM-A stem, a modified S-ROM stem for Asians. METHODS: We previously reported short-term outcomes for all 220 dysplastic hips that underwent primary total hip arthroplasty with the S-ROM-A stem. Here, we followed the clinical and radiological outcomes of 201 of the 220 hips (91%) for a mean 11.4 years postoperatively. We also performed multivariate analysis to determine whether large anteversion angle adjustment was associated with increased osteolysis. RESULTS: The cumulative survival rate of the stem at 168 months postoperatively was 97.4%. Two hips underwent revision surgery, including 1 due to neck trunnionosis. Characteristic distal stem fracture occurred in 3 hips (1.5%). Most partial radiolucent lines observed around the sleeve early postoperatively disappeared by 7 years, postoperatively. Mild osteolysis occurred relatively frequently (20%), but a multivariate model adjusted for polyethylene type showed no significant association between the occurrence of osteolysis and anteversion adjustment of the modular stem (stem anteversion decreased ≤-20°, P = .829; stem anteversion increased ≥+20°, P = .619). CONCLUSION: Partial radiolucent lines early postoperatively do not affect long-term outcomes. The clinical benefits of actively adjusting the stem anteversion angle outweigh the mechanical risks. Mild osteolysis, stem fracture, and trunnionosis were relatively frequent complications. Analysis with longer follow-up and more cases are necessary to clearly determine if these complications are associated with the design modification.

Revision Total Hip Arthroplasty Using the Modular Proximal Stem Modified for Asians: Medium-Term Clinical Results and Perioperative Complications.

BACKGROUND: This study aimed to examine the medium-term clinical and radiological outcomes of revision THA using the S-ROM-A stem, a modification of the S-ROM stem intended for Asians. METHODS: Femoral reconstruction using the S-ROM-A stem was performed in 126 hips that underwent revision THA. All patients were followed for perioperative complications. In addition, clinical and radiographic outcomes at a mean of 8 (range 5-14) years postoperatively were evaluated in 96 hips of 86 patients (76%). RESULTS: The most common perioperative complication was a femoral fracture, occurring in 16 hips (13%), including 11 intraoperative and 5 postoperative fractures. Dislocation occurred in five hips (4.0%), infection in three hips (2.4%), and trunnionosis in two hips (1.6%), including late complications. The total second stem revision was performed in two hips while stem only second revision preserving the bone ingrown sleeve was performed in four hips. With a second revision for aseptic loosening as the endpoint, the 13-year stem survival rate was 100%. Hip function as assessed by the Japanese Orthopedic Association score improved from a mean of 48 points preoperatively to 87 points 8 years postoperatively (P < .05). Radiological evaluation at the final follow-up showed that 95 hips (99%) achieved bone ingrowth fixation and one hip (1%) achieved fibrous stable status. CONCLUSION: Revision THA using the S-ROM-A stem resulted in good medium-term outcomes. Although modifications of the stem length and shape may be effective in preventing fractures in Asians with relatively small body sizes, attention should be paid to the occurrence of trunnionosis, which may be associated with the decreased taper size.

The different failure modes of the connecting elements of the modular hip arthroplasty revision stem Revitan.

INTRODUCTION: Fracture of the femoral stem is the cause of ~1 % of revisions after total hip arthroplasty. The risk increases intrinsically with modularity, whereby modularity is particularly useful in revision arthroplasty. We present 7 cases of failure of a specific modular, tapered, fluted, titanium alloy Revitan stem and analyse the different failure modes. METHODS: Retrospective review of all Revitan stems revised at our institutions due to implant failure and analysis of clinical presentation, diagnostic workup, and failure mode. The retrieved components were analyzed by optical and scanning electron microscopy. RESULTS: A total of 7 cases were included. There was a significant time lag between symptom onset and correct diagnosis. Conventional radiographs and low-dose CT scans (CT scout imaging) were decisive for diagnosis. All failures occurred at the level of the connection between the proximal component and the distal part of the stem. Three different failure modes were identified: loosening of the proximal component, fatigue fracture of the connection pin, and distal loosening of the connection pin. No alterations of the microstructure or deviation from manufacturing specifications regarding dimensions were observed. Failure was caused by mechanical overload. CONCLUSION: Conventional radiographs are the mainstay in identifying failed modular stems. Repeated radiographs and low-dose CT scans may be helpful additions. No single modification of the connection will address all possible failure modes. Modularity of revision stems offers advantages up until insertion of the definitive stem. Monoblock definitive stems might overcome the potential mechanical weaknesses of modularity and should be considered in relatively young, heavy and active patients.

Extended trochanteric osteotomy (ETO) and fluted tapered modular stems in revision hip arthroplasty. Does ETO integrity or consolidation, really matter?

INTRODUCTION: The objective of this study was to assess if the fracture and/or non-union of extended trochanteric osteotomy (ETO) affected the behavior and survival of modular fluted and tapered distal fixation stems in revision total hip arthroplasties (rTHA). METHODS: We retrospectively analyzed 52 rTHA in 52 patients. Preoperative diagnoses were mechanical loosening (42 cases), septic loosening (8), periprosthetic fracture (1), and femoral stem fracture (1). According to the Paprosky classification, femoral bone stock deficiencies were 19 type-II, 26 type IIIA, and 7 type IIIB. We assessed the behavior of the osteotomy (union, fracture, migration) and the survival and behavior (integration and subsidence) of prosthetic femoral stems. RESULTS: ETO union and non-union rates were 84.61% (44 patients) and 15.38% (8 cases) respectively. There were twelve (23%) intra-operative fractures of the osteotomy fragment and 11 (21.15%) migrations (4.5 mm on average). We observed bone union in 39 (75%) stems and 13 (25%) stable fibrous unions. Nine (17.3%) stems subsided 7 mm (2-15 mm) on average before becoming stable. Stem subsidence and integration was not significantly affected by ETO fracture/no fracture or union/non-union. The postoperative Harris Hip Score (HHS) improved significantly as compared to the pre-operative HHS (38.41 ± 3.54 vs 85.29 ± 3.36; p < 0.01). Patients were followed up for 55 (24-100) months. The overall implant survival at the end of follow-up was 100%. CONCLUSIONS: In this series, neither the non-union nor the intra-operative fracture of the ETO segment affected the behavior or medium-term survival of femoral stems.