Modular Fluted Tapered Stems for Periprosthetic Femoral Fractures: Excellent Results in 171 Cases

Aseptic Revision Total Hip Arthroplasty Using Modular Fluted Tapered Stems

BACKGROUND

Modular fluted tapered (MFT) femoral components are frequently utilized in aseptic revision total hip arthroplasties (THAs). However, long-term follow-up has been limited. The purpose of this study was to update our prior series at long-term follow-up, with specific emphasis on implant survivorship, radiographic results, and complications in a large cohort of aseptic revision THAs using MFT stems.

METHODS

We retrospectively identified 515 aseptic femoral revisions performed with 2 MFT stem designs in the total joint registry of a single tertiary care academic institution from 1999 to 2013. Serial radiographs were reviewed for subsidence of >5 mm. The mean follow-up (and standard deviation) was 10 ± 5 years (range, 2 to 21 years). A competing risk model accounting for death was utilized.

RESULTS

The 15-year cumulative incidence of any revision was 12%. There were 57 revisions, 27 of which involved revision of the fluted tapered component (FTC). Dislocation (n = 19), periprosthetic joint infection (n = 15), and aseptic loosening of the FTC (n = 11) were the most common reasons for revision. The 15-year cumulative incidence of any reoperation was 16%. The 15-year cumulative incidences were 6% for any FTC revision and 2% for FTC revision for aseptic loosening. Stem subsidence of >5 mm occurred in 2% of unrevised cases, and all but 1 stem was stable at the most recent follow-up.

CONCLUSIONS

This large series of MFT stems used in aseptic revision THAs had a 2% incidence of subsequent revision of the FTC for aseptic loosening at 15 years. Dislocation and infection were the most common reasons for any revision.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Systemic Osteoporosis and Osteopenia Among Periprosthetic Fractures After Total Hip Arthroplasty

BACKGROUND

Most periprosthetic fractures following total hip arthroplasty (THA) are fragility fractures that qualify patients for osteoporosis diagnoses. However, it remains unknown how many patients were diagnosed who had osteoporosis before injury or received the proper evaluation, diagnosis, and treatment after injury.

METHODS

We identified 171 Vancouver B2 (109) and B3 (62) periprosthetic femur fractures treated with a modular fluted tapered stem from 2000 to 2018 at 1 institution. The mean patient age was 75 years (range, 35 to 94), 50% were women, and the mean body mass index was 29 (range, 17 to 60). We identified patients who had osteoporosis or osteopenia diagnoses, a fracture risk assessment tool (FRAX), bone mineral density (BMD) testing, an endocrinology consult, and osteoporosis medications. Age-appropriate BMD testing was defined as no later than 1 year after the recommended ages of 65 (women) or 70 years (men). The mean follow-up was 11 years (range, 4 to 21).

RESULTS

Falls from standing height caused 94% of fractures and thus, by definition, qualified as osteoporosis-defining events. The prevalence of osteoporosis diagnosis increased from 20% before periprosthetic fracture to 39% after (P < .001). The prevalence of osteopenia diagnosis increased from 13% before the fracture to 24% after (P < .001). The prevalence of either diagnosis increased from 24% before fracture to 44% after (P < .001). No patients had documented FRAX scores before fracture, and only 2% had scores after. The prevalence of BMD testing was 21% before fracture and 22% after (P = .88). By the end of the final follow-up, only 16% had received age-appropriate BMD testing. The proportion of patients who had endocrinology consults increased from 6% before the fracture to 25% after (P < .001). The proportion on bisphosphonate therapy was 19% before fracture and 25% after (P = .08).

CONCLUSIONS

Although most periprosthetic fractures following THA are fragility fractures that qualify patients for osteoporosis diagnoses, there remain major gaps in diagnosis, screening, endocrinology follow-up, and treatment. Like nonarthroplasty fragility fractures, a systematic approach is needed after periprosthetic fractures.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Modular fluted tapered stems in two-stage reimplantation of previously infected total hip arthroplasties

Aims

Uncemented implants are now commonly used at reimplantation of a two-stage revision total hip arthoplasty (THA) following periprosthetic joint infection (PJI). However, there is a paucity of data on the performance of the most commonly used uncemented femoral implants - modular fluted tapered (MFT) femoral components - in this setting. This study evaluated implant survival, radiological results, and clinical outcomes in a large cohort of reimplantation THAs using MFT components.

Methods

We identified 236 reimplantation THAs from a single tertiary care academic institution from September 2000 to September 2020. Two designs of MFT femoral components were used as part of an established two-stage exchange protocol for the treatment of PJI. Mean age at reimplantation was 65 years (SD 11), mean BMI was 32 kg/m2 (SD 7), and 46% (n = 109) were female. Mean follow-up was seven years (SD 4). A competing risk model accounting for death was used.

Results

The 15-year cumulative incidence of any revision was 24%. There were 48 revisions, with the most common reasons being dislocation (n = 25) and infection (n = 16). The 15-year cumulative incidence of any reoperation was 28%. Only 13 revisions involved the fluted tapered component (FTC), for a 15-year cumulative incidence of any FTC revision of 8%. Only two FTCs were revised for aseptic loosening, resulting in a 15-year cumulative incidence of FTC revision for aseptic loosening of 1%. Stem subsidence ≥ 5 mm occurred in 2% of unrevised cases. All stems were radiologically stable at most recent follow-up. Mean Harris Hip Score was 69 (SD 20) at most recent follow-up.

Conclusion

This series demonstrated that MFT components were durable and reliable in the setting of two-stage reimplantation THA for infection. While the incidence of aseptic loosening was very low, the incidence of any revision was 24% at 15 years, primarily due to dislocation and recurrent PJI.

What's New in Periprosthetic Femur Fractures?

BACKGROUND

Periprosthetic femur fracture (PFF) is one of the most common indications for reoperation following total hip arthroplasty.

METHODS/RESULTS

This article provides a review of a symposium on PFF that was presented at the American Association of Hip and Knee Surgeons 2023 annual meeting, including an overview of the Vancouver classification and its implications on treatment and subsequent complications, an updated approach to the management of intraoperative fractures, and finally, contemporary strategies for both osteosynthesis as well as revision arthroplasty for PFFs.

CONCLUSION

As the incidence of PPF continues to increase, arthroplasty and trauma surgeons must be prepared to address this challenging complication with a contemporary understanding of the treatment options and their outcomes.

Marlex Mesh Reconstruction of the Extensor Mechanism: A Concise 5-Year Follow-up of 2 Previous Reports

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Revision total hip arthroplasty using a modular fluted, tapered revision femoral component and interlocking screws in Vancouver B3 periprosthetic fractures with insufficient bone at the isthmus

Aims

Revision total hip arthroplasty in patients with Vancouver type B3 fractures with Paprosky type IIIA, IIIB, and IV femoral defects are difficult to treat. One option for Paprovsky type IIIB and IV defects involves modular cementless, tapered, revision femoral components in conjunction with distal interlocking screws. The aim of this study was to analyze the rate of reoperations and complications and union of the fracture, subsidence of the stem, mortality, and the clinical outcomes in these patients.

Methods

A total of 46 femoral components in patients with Vancouver B3 fractures (23 with Paprosky type IIIA, 19 with type IIIB, and four with type IV defects) in 46 patients were revised with a transfemoral approach using a modular, tapered, cementless revision Revitan curved femoral component with distal cone-in-cone fixation and prospectively followed for a mean of 48.8 months (SD 23.9; 24 to 112). The mean age of the patients was 80.4 years (66 to 100). Additional distal interlocking was also used in 23 fractures in which distal cone-in-cone fixation in the isthmus was < 3 cm.

Results

One patient (2.2%) died during the first postoperative year. After six months, 43 patients (93.5%) had osseous, and three had fibrous consolidation of the fracture and the bony flap, 42 (91.3%) had bony ingrowth and four had stable fibrous fixation of the stem. No patient had radiolucency around the interlocking screws and no screw broke. One patient had non-progressive subsidence and two had a dislocation. The mean Harris Hip Score increased from of 57.8 points (SD 7.9) three months postoperatively to 76.1 points (SD 10.7) 24 months postoperatively.

Conclusion

The 2° tapered, fluted revision femoral component with distal cone-in-cone-fixation, combined with additional distal interlocking in patients with bony deficiency at the isthmus, led to reproducibly good results in patients with a Vancouver B3 fracture and Paprosky type IIIA, IIIB, and IV defects with regard to union of the fracture, subsidence or loosening of the stem, and clinical outcomes.

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.

Effect of Fracture Type, Treatment, and Surgeon Training on Reoperation After Vancouver B Periprosthetic Femur Fractures

BACKGROUND

The treatment of Vancouver B periprosthetic proximal femur fractures (PPFFs) is complex due to the overlap between arthroplasty and orthopedic trauma techniques. Our purpose was to assess the effects of fracture type, treatment difference, and surgeon training on the risk of reoperation in Vancouver B PPFF.

METHODS

A collaborative research consortium of 11 centers retrospectively reviewed PPFFs from 2014 to 2019 to determine the effects of variations in surgeon expertise, fracture type, and treatment on surgical reoperation. Surgeons were classified as per fellowship training, fractures using the Vancouver classification, and treatment as open reduction internal fixation (ORIF) or revision total hip arthroplasty with or without ORIF. Regression analyses were performed with reoperation as the primary outcome.

RESULTS

Fracture type (Vancouver B3 versus B1: odds ratio [OR]: 5.70) was an independent risk factor for reoperation. No differences were found in reoperation rates with treatment (ORIF versus revision: OR 0.92, P = .883). Treatment by a nonarthroplasty-trained surgeon versus an arthroplasty specialist led to higher odds of reoperation in all Vancouver B fracture (OR: 2.87, P = .023); however, no significant differences were seen in the Vancouver B2 group alone (OR: 2.61, P = .139). Age was a significant risk factor for reoperation in all Vancouver B fractures (OR: 0.97, P = .004) and in the B2 fractures alone (OR: 0.96, P = .007).

CONCLUSION

Our study suggests that age and fracture type affect reoperation rates. Treatment type did not affect reoperation rates and the effect of surgeon training is unclear.

Monoblock tapered stems in management of UCS B2 and B3 periprosthetic fractures in revision total hip arthroplasty

Aims

United Classification System (UCS) B2 and B3 periprosthetic fractures in total hip arthroplasties (THAs) have been commonly managed with modular tapered stems. No study has evaluated the use of monoblock fluted tapered titanium stems for this indication. This study aimed to evaluate the effects of a monoblock stems on implant survivorship, postoperative outcomes, radiological outcomes, and osseointegration following treatment of THA UCS B2 and B3 periprosthetic fractures.

Methods

A retrospective review was conducted of all patients who underwent revision THA (rTHA) for periprosthetic UCS B2 and B3 periprosthetic fracture who received a single design monoblock fluted tapered titanium stem at two large, tertiary care, academic hospitals. A total of 72 patients met inclusion and exclusion criteria (68 UCS B2, and four UCS B3 fractures). Primary outcomes of interest were radiological stem subsidence (> 5 mm), radiological osseointegration, and fracture union. Sub-analysis was also done for 46 patients with minimum one-year follow-up.

Results

For the total cohort, stem osseointegration, fracture union, and stem subsidence were 98.6%, 98.6%, and 6.9%, respectively, at latest follow-up (mean follow-up 27.0 months (SD 22.4)). For patients with minimum one-year of follow-up, stem osseointegration, fracture union, and stem subsidence were 97.8%, 97.8%, and 6.5%, respectively.

Conclusion

Monoblock fluted stems can be an acceptable modality for the management of UCS B2 periprosthetic fractures in rTHAs due to high rates of stem osseointegration and survival, and the low rates of stem subsidence, and revision. Further research on the use of this stem for UCS B3 periprosthetic fractures is warranted to determine if the same conclusion can be made for this fracture pattern.

Revision Total Hip Arthroplasty with a Modular Fluted Tapered Stem for a Periprosthetic Femoral Fracture

Background

As the number of primary total hip arthroplasty procedures performed each year continues to rise, so too do the number of complications, including periprosthetic femoral fracture1-9. Vancouver B2 and B3 periprosthetic femoral fractures are difficult to treat because they require the surgeon to simultaneously manage a femoral fracture and gain new implant fixation. Fluted tapered stems have advanced the treatment of periprosthetic femoral fractures by providing immediate axial and rotational implant fixation distal to the fracture10-18. Modular fluted tapered stems provide the added practical advantage of allowing length and anteversion adjustment after implantation of the distal fixation portion of the stem.

Description

In this technique, a modified extended trochanteric osteotomy incorporating the fracture is utilized to gain access to the loose femoral implant and femoral diaphyseal canal. The femoral diaphyseal canal is then sequentially reamed in 1-mm increments. A fluted tapered stem with the appropriate length, diameter, and axial and rotational stability is inserted into the canal. A proximal body is then chosen that establishes the appropriate leg length, femoral offset, and version. The final proximal body is engaged into the fluted tapered stem. Finally, the fracture is fixed around the implant with a combination of cables or wires.

Alternatives

Historically, implants such as extensively porous coated stems were utilized to treat Vancouver B2 or B3 periprosthetic femoral fractures. Unfortunately, these implants were associated with high rates of failure and revision7,9.

Rationale

The introduction of a fluted tapered stem provided a more reliable implant that achieves immediate axial and rotational stability. In addition, utilizing a fluted tapered stem allowed for a more soft-tissue-preserving approach to these complex injuries, in turn allowing the fracture to be reduced around the implant proximally with cerclage cables and or wires. Modular fluted tapered stems provide the additional advantage of allowing the surgeon to modify leg length, offset, and femoral version, independently of the fluted tapered stem. As a result of these unique advantages, these stems were introduced several years ago for the treatment of Vancouver B2 or B3 periprosthetic femoral fractures.

Expected Outcomes

Contemporary series have demonstrated that the use of a modular fluted tapered stem leads to improved implant survivorship and clinical outcomes with lower complication rates for Vancouver B2 and B3 periprosthetic femoral fractures1,10-12,14-19.

Important Tips

Template both the fluted tapered stem and proximal body preoperatively. The proximal body should be templated at the ideal hip center of rotation that appropriately restores leg lengths and offset. Template the fluted tapered stem so that it provides appropriate isthmic fit and bypasses the most distal extent of the fracture by at least 2 cortical diameters.Utilize a modified extended trochanteric osteotomy for your exposure in order to facilitate visualization of the fracture and to provide direct access to the femoral canal.Place a prophylactic cable prior to preparing the femur for the implant in order to help prevent iatrogenic fracture.Place a trial stem and obtain intraoperative anteroposterior and lateral radiographs in order to assess the position of the implants and the risk of anterior cortical perforation.When placing the final implants, be sure the fluted tapered stem has both axial and rotational stability.Reduce and fix the fracture after the final implants are placed and the hip is reduced.

Acronyms and Abbreviations

AP = anteroposteriorMFT = modular fluted tapered (stem)ETO = extended trochanteric osteotomyTHA = total hip arthroplastyCT = computed tomographyPJI = periprosthetic joint infection.