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Impaction bone grafting for femoral revision hip arthroplasty with Exeter stem in Japan: An extended 10- to 15-year stem survival analysis of the previously reported series
Femoral impaction bone grafting (IBG) was introduced in the late 1990s in Japan and has gradually become recognized as a useful option for femoral revision. The aim of the present study was to retrospectively analyze 10 to 15 years of clinical results of femoral revision arthroplasties of IBG using Exeter stem performed by experienced Japanese surgeons.
Methods
We investigated radiographic and clinical records more than 2 years after surgery in 99 hips of 93 patients. The average age was 66.3 years (36–84 years) and the average follow-up period was 11 years (2–23 years and 8 months). Merle d’Aubigné and Postel hip score was used for clinical assessment, and re-operations for any reason were recorded. The survival curve was estimated using Kaplan-Meier method.
Results
The mean Merle d’Aubigné and Postel hip score improved from 9.0 points to 14.5 points at the final follow-up. Re-operations were undertaken in 15 hips of 14 patients for aseptic acetabular component loosening (n = 1 hip), recurrent dislocation (n = 2 hips), infection (n = 4 hips), and periprosthetic femoral fracture (n = 8 hips). The survival rates at 10 and 15 years after operation were 87.1% and 81.1% with any type of re-operation as the endpoint, 92.2% and 92.2% with stem removal or exchange as the endpoint, 94.9% and 88.1% with re-operation for periprosthetic femoral fracture as the endpoint, and 99.0% and 99.0% with re-operation for aseptic stem loosening as the endpoint, respectively.
Conclusions
The present study showed encouraging results of femoral IBG over 10 years by experienced surgeons in Japan. Although femoral IBG is recognized as a technically complex procedure, survivorship of the stem is excellent, with a 15-year stem survival rate of 99.0% at the end point of aseptic loosening.
Periprosthetic bone stock loss is a challenging condition both for patients and surgeons following revision total hip arthroplasty. Since impaction bone grafting [
], an increasing number of surgeons are adopting femoral side revision.
The authors have already reported short-term encouraging results (average 5.2 years follow-up) of revision total hip arthroplasty with femoral impaction bone grafting using Exeter stem (Stryker International, Mahwah, NJ, USA) in 99 hips of 93 cases, and reported survival rates at 8 years after operation of 94.8% with femoral fractures as the end point, 93.1% with any stem removal or exchange as the end point, and 99.0% with aseptic stem loosening as the end point [
Recently, good long-term follow-up results concerning this technique have been published from centers in European countries. They reported that femoral impaction bone grafting is a valuable biological revision technique for cases with femoral bone stock loss, as it results in a stable and durable treatment option [
The outcome of femoral component revision arthroplasty with impaction allograft bone grafting and a cemented polished Exeter stem. A prospective cohort study of 208 revision arthroplasties with mean follow-up of ten years.
It is clinically beneficial to verify whether the therapeutic effect of surgical interventions can be maintained for a long period of time; thus, the follow-up of the patient cohort of this study was continued. As the postoperative follow-up period increases, so does the patient's age; thus, the incidence of additional periprosthetic fractures was also investigated.
The aim of this paper was to follow up a previous study conducted 10 years ago about the outcome of femoral impaction grafting performed in 99 hips of 93 patients at our institutions.
2. Patients and methods
Between February 1997 and December 2007, four surgeons (TI, HO, NK, HF) performed 103 femoral revisions with the impaction bone grafting technique using Exeter stem in 97 patients. One patient died because of an unrelated disease within 2 years of surgery, and three patients were lost from follow-up within 2 years after surgery; therefore, we investigated radiographic findings and clinical records more than 2 years after surgery in 99 hips of 93 patients. The indications for surgery were aseptic loosening of the femoral stem (n = 79 hips), secondary reconstruction after controlled deep infection (n = 11 hips), femoral osteolysis (n = 6 hips), and periprosthetic fracture with aseptic loosening (n = 3 hips). The average age of the patients at revision surgery was 66.3 years (range 36–84 years), comprising 72 women and 21 men. The average follow-up period was 11 years (range 2–23 years and 8 months). Femoral bone defects were classified according to Endo-Klinik classification [
]: grade I, radiolucent lines confined to the upper half of the cement mantle and clinical signs of loosening (n = 4 hips); grade II, generalized radiolucent zones and endosteal erosion of the upper femur leading to widening of the medullary cavity (n = 37 hips); grade III, widening of the medullary cavity by expansion of the upper femur (n = 42 hips); and grade IV, gross destruction of the upper third of the femur with involvement of the middle third that precluded the insertion of even a long-stemmed prosthesis (n = 16 hips).
Operative techniques have been described in detail elsewhere [
] was used in all cases using the X-change revision system (Stryker International, Mahwah, NJ, USA). If the femoral canal was too narrow to use the smallest proximal packer in the X-change system, manual bone packing was performed using appropriate stem trials. After enough bone packing within the femoral canal, retrograde cement dough (Simplex P Bone Cement, Stryker Limerick, Limerick, Ireland) filling using a cement gun followed by cement pressurization was performed. An appropriately sized Exeter stem was then inserted to the appropriate level to reproduce the trial setting.
2.1 Assessment
All assessment data were collected by one of the authors (TI), and a database was created for the following retrospective analysis.
For clinical assessment, the Merle d’Aubigné and Postel hip score [
] was assessed preoperatively and at the final follow-up. Post-operative regional complications, such as dislocation, periprosthetic joint infection (PJI), and periprosthetic femoral fractures, were recorded throughout the follow-up period. Periprosthetic fractures were classified using the Vancouver classification [
For radiological assessment, antero-posterior (AP) hip radiographs of all hips were evaluated at the final follow-up and compared with all earlier pre- and post-operative radiographs by all co-authors, who agreed a consensus opinion. The radiographs were evaluated for subsidence according to the method of Fowler et al. [
]. All the measurements were corrected for magnification using the known dimensions of the femoral head. Radiographic failure was defined as a circumferential radiolucent line or osteolysis in all seven Gruen zones on an AP view and/or a progressive stem subsidence >5 mm/year.
Furthermore, any re-operations to the ipsilateral hip joint or femur were recorded.
2.2 Statistical analysis (survival curves)
We analyzed details of the cases and recorded the reasons for re-operation. Survival curves were estimated by the Kaplan–Meier method [
], a graphical user interface for R 3.4.3 (R Foundation for statistical Computing, Vienna, Austria). The primary endpoints were any type of femoral re-operation, stem removal or exchange, re-operation for periprosthetic femoral fracture, and re-operation for aseptic stem loosening at 10 and 15 years.
2.3 Ethical approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
2.4 Informed consent
Informed consent was obtained from all patients prior to the start of the study according to respective institutional regulations.
Furthermore, the institute's Local Review Board approved this study (R1-No. 16).
3. Results
3.1 Clinical assessment
Two hips that had undergone resection arthroplasty for recurrent deep infection were excluded from the clinical scoring assessment in the previous study. The mean Merle d’Aubigné and Postel hip score of the remaining 97 hips improved from 9.0 points (SD 3.6; range 1–17 points) before operation to 14.5 points (SD 2.1; range 9–18 points) at the latest follow-up assessment.
Recurrent dislocation occurred in two hips and cup revisions were performed in these cases (stem exchange = 1 hip, stem preservation = 1 hip).
For periprosthetic joint infection (n = 4 hips), implant removal (n = 2 hips), and successful two stage revision (n = 2 hips) were performed.
In the previous follow-up of the present series, five periprosthetic fractures (Vancouver type B1 fracture = 3 hips, type B2 fracture = 1 hip, and type C fracture = 1 hips) occurred within 2 years and 2 months after operation, and four of them had pre-operative or intraoperative fractures. Three more periprosthetic fractures (one Vancouver B1 fracture and two Vancouver type C fractures) occurred until the latest follow-up period and all of them are treated by internal fixation with stem in situ. Those additional three periprosthetic fractures occurred from 11 years 4 months–12 years and 8 months post-operatively; thus, there may be little influence of impaction bone grafting itself on those cases, because more than ten years had passed after surgery.
Post-operative periprosthetic femoral fractures during the whole follow-up period occurred in eight hips (Vancouver type B1 fracture in 4 hips, type B2 fracture in 1 hip, and type C fracture in 3 hips).
As treatment for periprosthetic fractures, open reduction and internal fixation (ORIF) was performed in Vancouver type B1 fractures (n = 4) and in type C fractures (n = 3); furthermore, re-revision was performed in one Vancouver type B2 fracture (Table 1).
Table 1List of re-operations during follow-up period.
Comparison between the distribution of stem subsidence amount at the former follow-up (average 5 years and 2 months) and at the latest follow-up (average 11 years) is shown in Fig. 1. Between the two follow-ups, although stem subsidence had slightly progressed, no additional case showed more than 5-mm stem subsidence compared to the earlier follow-up.
Fig. 1Comparison of the distribution of stem subsidence amount between the former follow-up (average 5 years and 2 months) and the latest follow-up (average 11 years).
No case showed radiographic failure with circumferential radiolucent line, osteolytic region, or progressive stem subsidence >5 mm/year.
3.3 Re-operations
During the follow-up period, re-operations were performed in 15 hips of 14 patients (Table 1) for aseptic acetabular component loosening (one hip of one patient), recurrent dislocation (two hips of two patients), for PJI (four hips of three patients), and for periprosthetic femoral fracture (eight hips of eight patients). Of those re-operations, stem removal was performed in three hips and stem exchange in four hips (in-cement technique = 2 hips, cement-in-cement technique = 1 hip, revision with cementless long stem = 1 hip).
3.4 Survival curves
Kaplan-Meier survival analysis revealed that the survival rates with any type of re-operation as the endpoint were 87.1% (95% confidential interval [CI]: 78.4–92.5%) at 10 years and 81.1% (95% CI: 69.7–88.5%) at 15 years (Fig. 2a). The survival rate with stem removal or exchange as the endpoint was 92.2% (95% CI: 84.2–96.2%) at both 10 and 15 years (Fig. 2b). The survival rates with re-operation for periprosthetic femoral fracture as the endpoint were 94.9% (95% CI: 88.2–97.9%) at 10 years and 88.1% (95% CI: 76.4–94.3%) at 15 years (Fig. 2c). The survival rates with re-operation for aseptic stem loosening as the endpoint were 99.0% (95% CI: 93.0–99.9%) at both 10 years and 15 years (Fig. 2d).
Fig. 2Kaplan-Meier survival curves of the stem with various endpoints. Dotted lines indicate 95% confidential interval (95% CI). (a) Survival curve with an endpoint of any type of re-operation. (b) Survival curve with an endpoint of stem removal or exchange. (c) Survival curve with an endpoint of re-operation for periprosthetic femoral fracture. (d) Survival curve with an endpoint of re-operation for aseptic stem loosening.
There are several options for reconstruction of femoral deficiencies. Since the late 1990s, we have used femoral impaction bone grafting revision as the main option for femoral revision hip arthroplasty, as it has good mid-term clinical results [
The outcome of femoral component revision arthroplasty with impaction allograft bone grafting and a cemented polished Exeter stem. A prospective cohort study of 208 revision arthroplasties with mean follow-up of ten years.
]. Survival rates at 5 years after the operation were 94.8% with femoral fractures as the end point, 95.3% with any stem removal or exchange as the end point, and 99.0% with aseptic stem loosening as the end point.
As the patients have been followed continuously, we verified the longer time effect of this femoral revision technique, which was adopted at an early stage.
Including the center where it originated and several western countries, more than 10 years of follow-up results have been reported [
The outcome of femoral component revision arthroplasty with impaction allograft bone grafting and a cemented polished Exeter stem. A prospective cohort study of 208 revision arthroplasties with mean follow-up of ten years.
]. Wilson et al. from Princess Elizabeth Orthopaedic Centre (Exeter, UK), which was the center where femoral impaction bone grafting originated, reported the 20-year survival rate for the entire series of 705 revisions was 98.8% with aseptic loosening as the endpoint, and 87.7% for revision for any reason (mean follow-up = 14.7 years) [
]. Te Stroet et al. from Radboud University Medical Center (Nijmegen, Netherlands), which was the joint development facility of femoral impaction bone grafting, reported a 10-year survival rate for 208 revisions of 94.9% with femoral re-revision for any reason as the endpoint, 99.4% with femoral re-revision for aseptic loosening as the endpoint, and 84.5% with femoral re-operation for any reason as the endpoint (mean follow-up = 10.6 years) [
The outcome of femoral component revision arthroplasty with impaction allograft bone grafting and a cemented polished Exeter stem. A prospective cohort study of 208 revision arthroplasties with mean follow-up of ten years.
In the present study, we reported the 10-year survival rate for 99 revisions, which were 87.1% with any type of re-operation as the endpoint, 92.2% with stem removal or exchange as the endpoint, 94.9% with re-operation for periprosthetic femoral fracture as the endpoint, and 99.0% with re-operation for aseptic stem loosening as the endpoint. To the best of our knowledge, the present study was the first follow-up report of over 10 years of a relatively large number of femoral impaction bone grafting cases for Asian patients. Asian patients tend to have small physiques and a relatively narrow femoral canal and have almost comparable stem survival rate to those from the previous studies from the centers where the technique originated. This suggests that femoral impaction bone grafting is globally useful femoral revision option.
To achieve good long-term results, it is necessary to recognize the failure mode of femoral impaction bone grafting and prevent it from occurring.
As intraoperative and postoperative femoral fractures are the most frequent failure modes, surgeons should strive to avoid these complications. Aggressive augmentation with metal or bone plates to confirm femoral configuration and using a long stem to bypass the weak point of the femoral shaft (stress riser) are important for avoiding post-operative femoral periprosthetic fracture [
The effect of preoperative planning and impaction grafting surgical technique on intraoperative and postoperative complication rate for femoral revision patients with moderate to severe bone loss mean 4.7 year results.
] (Fig. 3, Fig. 4). In a previous follow-up of the present series, five periprosthetic fractures occurred within 2 years and 2 months after operation; moreover, four of them had pre-operative or intraoperative fractures. In addition, three more periprosthetic fractures (Vancouver B1 fracture = 1, and Vancouver type C fractures = 2) occurred until the latest follow-up period and all of them were treated by internal fixation with stem in situ. Those additional three periprosthetic fractures occurred from 11 years 4 months–12 years and 8 months post-operatively, and there may be little influence of impaction bone grafting itself on those cases, as more than ten years had passed after the surgery. However, the Vancouver C fractures occurred in two octogenarians; thus, they may have required continuous postoperative care for osteoporosis.
Fig. 3Seventy-year-old female showing aseptic loosening of cemented long stem of right hemiarthroplasty with Endo-Klinik grade IV femoral bone defect. (a) Preoperative radiographic finding. (b) Intra-operative findings showing thin femoral cortex with massive femoral wall defect. (c) Impaction bone grafting with aggressive augmentation using metal mesh and strut allogenic bone plates are performed for reconstruction.
The influence of cemented femoral stem choice on the incidence of revision for periprosthetic fracture after primary total hip arthroplasty: an analysis of national joint registry data.
Reduced periprosthetic fracture rate when changing from a tapered polished stem to an anatomical stem for cemented hip arthroplasty: an observational prospective cohort study with a follow-up of 2 years.
More reoperations for periprosthetic fracture after cemented hemiarthroplasty with polished taper-slip stems than after anatomical and straight stems in the treatment of hip fractures. A study from the Norwegian hip fracture register 2005 to 2016.
]. On the other hand, according to the analysis of the National Joint Registry of England & Wales, Exeter stem showed the highest 8-year survival rate with the end point of revision for any reason compared to the other type of polished tapered stem and composite beam stem [
]. Lamb et al. reported risk factors associated with periprosthetic fracture revision following total hip arthroplasty with cemented polished tapered stems such as increasing age, intraoperative fracture, ovaloid and round cross-sectional shapes, increasing stem offset, increasing head size, cobalt-chromium stem material, and cobalt-chromium stems with low-viscosity cement [
Risk factors for revision of polished taper-slip cemented stems for periprosthetic femoral fracture after primary total hip replacement: a registry-based cohort study from the national joint registry for England, Wales, Northern Ireland and the Isle of Man.
in: Gie G.A. Timperley A.L. Crawford R. Hubble M.J.W. Howell J.R. Charity J. The Exeter Hip. 2nd edition. 50 years of innovation in total hip arthroplasty. Exeter hip publishing,
Exeter, UK)2020: 7-15
The effect of preoperative planning and impaction grafting surgical technique on intraoperative and postoperative complication rate for femoral revision patients with moderate to severe bone loss mean 4.7 year results.
]. Biomechanical examination showed Exeter stem was stronger than other brands of cemented polished tapered stem in terms of periprosthetic fracture generation torque [
], which may protect femoral bone atrophy due to stress shielding.
There were several limitations to our study. First, because it involved a retrospective clinical case cohort design, we lacked a control group of patients who underwent other techniques. Second, it was also a multi-surgeon series. This study represents a consecutive series of patients and includes the first cases and learning curve of each surgeon responsible for the development of their own operative technique. Third, manual measurements of the stem subsidence were also less accurate than other methods such as computer-assisted technologies.
This is the first study series report with an average of over 10 years follow-up, which consisted of about 100 complex femoral stem revision cases in Asian countries. The present findings will encourage hip surgeons to continue using femoral impaction bone grafting as an essential technique for revision arthroplasty.
5. Conclusions
In conclusion, this was a multi-center, multi-surgeon, over 10-year follow-up series of the use of impaction grafting for revision total hip arthroplasty in Japan. Although impaction bone grafting is recognized as technically complex procedure, we have shown survivorship of the stem to be excellent, with a 15-year stem survival rate of 99.0% at the end point of aseptic loosening.
Declaration of competing interest
None of the authors has anything to declare regarding conflict of interest, nor does any author have a relationship with any funding companies.
Acknowledgments
The authors would like to express our deepest gratitude to Mr. Graham A Gie, Prof. Andrew John Timperley, Prof. Ross Crawford, Mr. Matthew J. W. Hubble, and colleagues in Princess Elizabeth Orthopaedic Centre (Exeter, UK) for their kind technical guidance in introducing the impaction bone grafting technique in Japan.
References
Gie G.A.
Linder L.
Ling R.S.
Simon J.P.
Slooff T.J.
Timperley A.J.
Impacted cancellous allografts and cement for revision total hip arthroplasty.
The outcome of femoral component revision arthroplasty with impaction allograft bone grafting and a cemented polished Exeter stem. A prospective cohort study of 208 revision arthroplasties with mean follow-up of ten years.
The effect of preoperative planning and impaction grafting surgical technique on intraoperative and postoperative complication rate for femoral revision patients with moderate to severe bone loss mean 4.7 year results.
The influence of cemented femoral stem choice on the incidence of revision for periprosthetic fracture after primary total hip arthroplasty: an analysis of national joint registry data.
Reduced periprosthetic fracture rate when changing from a tapered polished stem to an anatomical stem for cemented hip arthroplasty: an observational prospective cohort study with a follow-up of 2 years.
More reoperations for periprosthetic fracture after cemented hemiarthroplasty with polished taper-slip stems than after anatomical and straight stems in the treatment of hip fractures. A study from the Norwegian hip fracture register 2005 to 2016.
Risk factors for revision of polished taper-slip cemented stems for periprosthetic femoral fracture after primary total hip replacement: a registry-based cohort study from the national joint registry for England, Wales, Northern Ireland and the Isle of Man.
in: Gie G.A. Timperley A.L. Crawford R. Hubble M.J.W. Howell J.R. Charity J. The Exeter Hip. 2nd edition. 50 years of innovation in total hip arthroplasty. Exeter hip publishing,
Exeter, UK)2020: 7-15
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