Revision total hip arthroplasty using third-generation cementing technique

The use of a standard-length conical tapered stem in hip revision arthroplasty to address Paprosky type I-II femoral defects: a prospective study of 87 patients

INTRODUCTION

Low-grade femoral defects in revision total hip arthroplasty (rTHA) might be preferably treated with a primary implant. Almost no previous study reported the use of standard-length conical tapered (SLCT) stems in these cases. We analyzed a series of cases using a SLCT stem in rTHA with Paprosky type I-II femoral defects. The purpose of the study was to determine clinical and radiographic outcomes in this series of rTHA.

MATERIALS AND METHODS

We prospectively followed 87 patients undergoing a femoral component rTHA: 53 Paprosky type I and 34 type II femoral defects. Patient-reported measures (Oxford Hip Score, EQ-5D, VAS pain during rest and activity) were administered at baseline, 1 and 2 years post-operatively. Radiographic subsidence overtime was scored. Kaplan-Meier curves were used to evaluate the subsidence over time, the complication-free survival, and the implant survivorship with reoperation and stem revision as endpoints.

RESULTS

The mean follow-up was 72.5 (SD ± 23.9) months. All PROMs significatively improved over time. The average subsidence was 2.8 (SD ± 3.2), 3.6 (SD ± 4.4), and 4.0 (SD ± 4.9) mm at 4, 12, and 24 months respectively. 6 stems had subsidence > 10 mm. The survival without complication was 0.85 (95% CI 0.94-0.77), while the implant survival without reoperation was 0.83 (95% CI 0.95-0.72). The overall stem survival rate was 93.7% (95% CI 0.91-0.97) at 2 years.

CONCLUSION

The use of a SLCT stem in rTHA with Paprosky type I-II femoral defects demonstrated good survival with low subsidence rates during the first 2 years after surgery. Surgeons should consider the use of this primary prosthesis as a potential treatment during stem revision in cases with limited femoral bone loss.

Stay Short or Go Long in Revision Total Hip Arthroplasty With Paprosky Type II Femoral Defects: A Comparative Study With the Use of an Uncemented Distal Fixating Modular Stem and a Primary Monobloc Conical Stem With 5-Year Follow-Up

BACKGROUND

In the revisions for Paprosky type II femoral defects, diaphyseal fixating femoral stems are commonly used. To preserve bone stock, the use of a shorter primary conical stem could be an adequate alternative. The objective of this study is to compare the results of a primary conical stem to the more commonly used diaphyseal fixating modular revision stem in revision total hip arthroplasty surgery with Paprosky type II femoral defects.

METHODS

A total of 59 consecutive patients with Paprosky type II femoral defects from our prospective revision registry were included. Thirty patients who received a long distal fixating modular stem (Revision Stem, Lima Corporate) and 29 patients who received a primary conical short stem (Wagner Cone, Zimmer) were prospectively followed. Minimal follow-up time was 2 years for subsidence and patient-reported outcome measures and 5 years for complications, reoperation, and revision. We compared subsidence, perioperative complications, reoperations, femoral component survival, Oxford Hip Score, EuroQol 5 Dimension, visual analog scale (VAS) for pain at rest, and VAS for pain during activity between stems.

RESULTS

Both groups were comparable regarding demographic, clinical, and surgery-related characteristics. We found more perioperative complications and stem revisions with the modular revision stem than with the primary conical stem. There were no statistical differences in subsidence, EuroQol 5 Dimension, Oxford Hip Score, and VAS for pain at rest or during activity between both stems.

CONCLUSION

In revision total hip arthroplasty with Paprosky type II femoral defects, uncemented primary monobloc conical femoral stems showed the same clinical result as distal fixating modular stems with fewer complications and fewer stem revisions.

A Role for Modern Primary Cementless Femoral Stems in Revision Hip Arthroplasty

BACKGROUND

In revision total hip arthroplasty (THA) cases with preserved femoral metaphyseal bone, tapered proximally porous-coated "primary" femoral stems may be an option. The objective of this study was to compare outcomes of patients with Paprosky I or II femoral bone loss undergoing revision THA with either a primary metaphyseal-engaging cementless stem or a revision diaphyseal-engaging stem.

METHODS

This was a retrospective analysis of 70 patients with Paprosky I or II femoral bone loss who underwent femoral revision. 35 patients who were revised using a primary cementless femoral stem were compared with 35 patients who underwent femoral revision using a revision diaphyseal-engaging stem. The groups were similar regarding age, gender, body mass index, and American Society of Anesthesiologists. Clinical and radiographic outcomes and complications were compared over an average follow-up of 2.9 years (SD 1.4).

RESULTS

Revision THA was most commonly performed for periprosthetic joint infection (N = 27, 38.6%). The groups were similar with regards to Paprosky femoral classification (P = .56), length of stay (P = .68), discharge disposition (P = .461), operative time (P = .20), and complications (P = .164). There were no significant differences between primary and revision femoral stem subsidence (0.12 vs. 0.75 mm, P = .18), leg length discrepancy (2.3 vs. 4.05 mm, P = .37), and Hip Disability and Osteoarthritis Outcome Score Jr (73.1 [SD 21.1] vs. 62.8 [SD 21.7], P = .088). No patient underwent additional revision surgery involving the femoral component.

CONCLUSION

Use of modern primary cementless femoral stems is a viable option for revision hip arthroplasty in the setting of preserved proximal femoral metaphyseal bone. Outcomes are not inferior to those of revision stems and offer potential benefits.

Charnley femoral cemented stem with a permeable and resorbable cement restrictor and low-viscosity cement - Clinical and radiographical evaluation of 100 cases at a mean follow-up of 6.55 years

INTRODUCTION

In 1979, in his first book dealing with low-friction arthroplasty (LFA), Charnley highlighted the use of a cement restrictor. Breusch and Malchau described in 2005 the "second-generation cementing technique." The main objective of this study was to report on the clinical survival of 100 cases of Charnley femoral component implanted in 2007 and 2008 using a permeable and resorbable cement restrictor and a low-viscosity antibiotic-loaded cement. The secondary objectives were to analyze the complications and side effects and the accuracy of the device positioning.

MATERIAL AND METHODS

This was a monocentric retrospective review of a prospectively compiled database. Diaphyseal restrictor was biodegradable and permeable to gas, blood, and fluids to avoid intramedullary over pression during cementation. The cement was a low-viscosity antibiotic-loaded cement. Among 3555 patients, we selected the first continuous 100 cases of patients where we implanted the device. Survival probability was computed according to Kaplan-Meier method.

RESULTS

Mean follow-up was 6.55 ± 2.6 (range 1-11). Considering femoral component revision as the endpoint, survival rate was 100%. No patients died intraoperatively, none in the first month and the first year after surgery. No early periprosthetic fractures have been reported.

DISCUSSION

As described initially by Charnley, the use of a cement restrictor was highly recommended through the different generations of cementing techniques. Hypotensive episodes and cardiac arrest have been reported during cement insertion. In our series, we did not deplore any adverse effect related to the cementation.

CONCLUSION

Our study demonstrates a 100% survival rate of a cemented femoral component without adverse effects when using routinely a resorbable and permeable cement restrictor and a low-viscosity cement. Bone cement is still a fantastic ally for the surgeon and the patients.

Femoral revision with primary cementless stems: a systematic review of the literature

The use of primary cementless stems in femoral revision has gained popularity, but no clear consensus about the correct indication is still present. The aim of our systematic review is to: (1) summarize the available literature focused on the use of cementless primary stem in revision total hip arthroplasty (THA); (2) evaluate whether the use of cementless primary stems could represent a feasible option in hip revision; (3) define the proper indication of this surgical approach. A systematic literature review was performed about the use of cementless primary stems in revision THA. The PRISMA 2009 checklist was considered to edit our review. A total of nine articles were included. The current evidence is primarily Level IV. A total of 439 patients (454 hips) underwent THA revision with primary cementless stem. Partial cementless porous coated stems were used in 246 hips (54.2%). The majority of patients were affected by type I or II Paprosky femoral defects. The mean stem-related survival rate is 95.6% ± 3.8 with a mean follow-up of 4.7 years ± 1.3. Poor standardization of methodological analysis was observed. Current literature shows lacking evidence about primary cementless stems in revision THA. Despite these limitations, we can affirm that primary cementless stems in femoral revision surgery represent a viable option in selected patients. The proper indication is a patient with femoral Paprosky defect types I or II, with low number of previous surgeries and a previous cementless stem.

Optimization of a Functionally Graded Material Stem in the Femoral Component of a Cemented Hip Arthroplasty: Influence of Dimensionality of FGM

The longevity of hip prostheses is contingent on the stability of the implant within the cavity of the femur bone. The cemented fixation was mostly adopted owing to offering the immediate stability from cement-stem and cement-bone bonding interfaces after implant surgery. Yet cement damage and stress shielding of the bone were proven to adversely affect the lifelong stability of the implant, especially among younger subjects who tend to have an active lifestyle. The geometry and material distribution of the implant can be optimized more efficiently with a three-dimensional realistic design of a functionally graded material (FGM). We report an efficient numerical technique for achieving this objective, for maximum performance stress shielding and the rate of early accumulation of cement damage were concurrently minimized. Results indicated less stress shielding and similar cement damage rates with a 2D-FGM implant compared to 1D-FGM and Titanium alloy implants.

Minimizing Stress Shielding and Cement Damage in Cemented Femoral Component of a Hip Prosthesis through Computational Design Optimization

The average life expectancy of many people undergoing total hip replacement (THR) exceeds twenty-five years and the demand for implants that increase the load-bearing capability of the bone without affecting the short- or long-term stability of the prosthesis is high. Mechanical failure owing to cement damage and stress shielding of the bone are the main factors affecting the long-term survival of cemented hip prostheses and implant design must realistically adjust to balance between these two conflicting effects. In the following analysis we introduce a novel methodology to achieve this objective, the numerical technique combines automatic and realistic modeling of the implant and embedding medium, and finite element analysis to assess the levels of stress shielding and cement damage and, finally, global optimization, using orthogonal arrays and probabilistic restarts, were used. Applications to implants, fabricated using a homogeneous material and a functionally graded material, were presented.

Femoral Component Revision of Total Hip Arthroplasty

Modern primary total hip arthroplasty (THA) is among the most successful operations in medicine. It has been a consistently effective treatment for end-stage osteoarthritis of the hip. With the increasing number of primary THA procedures being performed and the decreasing age of patients undergoing the procedure, there is an inevitable associated increase in revision burden for arthroplasty surgeons. Revision THA is most often indicated for instability, aseptic loosening, osteolysis, infection, periprosthetic fracture, component malposition, and catastrophic implant failure. Understanding the etiology of THA failure is essential for guiding clinical decision making. Femoral component revision presents a complex challenge to the arthroplasty surgeon because of modern implant design as well as bone loss in the proximal femur. Thorough patient evaluation, defect classification, and well-executed surgical reconstruction based on comprehensive preoperative planning may determine the postoperative results. Knowledge of various reconstructive options and the indications for each is necessary to achieve a successful outcome. This article highlights the most common indications for revision after THA and offers recommendations for how to approach revision of the femoral component. Specifically, the authors review preoperative assessment, common classification systems for femoral deficiency, techniques for component extraction, and modalities of femoral component fixation. [Orthopedics. 2016; 39(6):e1129-e1139.].

Performance of bioactive PMMA-based bone cement under load-bearing conditions: an in vivo evaluation and FE simulation

In the past, bioactive bone cement was investigated in order to improve the durability of cemented arthroplasties by strengthening the bone-cement interface. As direct bone-cement bonding may theoretically lead to higher stresses within the cement, the question arises, whether polymethylmethacrylate features suitable mechanical properties to withstand altered stress conditions? To answer this question, in vivo experiments and finite element simulations were conducted. Twelve rabbits were divided into two groups examining either bioactive polymethylmethacrylate-based cement with unchanged mechanical properties or commercially available polymethylmethacrylate cement. The cements were tested under load-bearing conditions over a period of 7 months, using a spacer prosthesis cemented into the femur. For the finite element analyses, boundary conditions of the rabbit femur were simulated and analyses were performed with respect to different loading scenarios. Calculations of equivalent stress distributions within the cements were applied, with a completely bonded cement surface for the bioactive cement and with a continuously interfering fibrous tissue layer for the reference cement. The bioactive cement revealed good in vivo bioactivity. In the bioactive cement group two failures (33 %), with complete break-out of the prosthesis occurred, while none in the reference group. Finite element analyses of simulated bioactive cement fixation showed an increase in maximal equivalent stress by 49.2 to 109.4 % compared to the simulation of reference cement. The two failures as well as an increase in calculated equivalent stress highlight the importance of fatigue properties of polymethylmethacrylate in general and especially when developing bioactive cements designated for load-bearing conditions.

Medium-term follow-up of 92 femoral component revisions using a third-generation cementing technique

BACKGROUND AND PURPOSE

Very little has been published on the outcome of femoral cemented revisions using a third-generation cementing technique. We report the medium-term outcome of a consecutive series of patients treated in this way.

PATIENTS AND METHODS

This study included 92 consecutive cemented femoral revisions performed in our department with a third-generation cementing technique and without instrumented bone impaction grafting between 1996 and 2007. The average age of the patients at revision was 66 (25-92) years. None of the patients were lost to follow-up. At review in December 2013, 55 patients were still alive and had a non-re-revised femoral revision component in situ after a mean follow-up of 11 (5-17) years.

RESULTS

The mean preoperative Harris hip score was 50, and improved to 73 at final follow-up. 2 patients died shortly after the revision surgery. 1 stem was re-revised for aseptic loosening; this was also the only case with radiolucent lines in all 7 Gruen zones. A femoral reoperation was performed in 19 hips during follow-up, and in 14 of these 19 reoperations the femoral component was re-revised. Survivorship at 10 years, with femoral re-revision for any reason as the endpoint, was 86% (95% CI: 77-92). However, excluding 8 patients with reinfections after septic index revisions and 1 with hematogenous spread of infection from the survival analysis, the adjusted survival for re-revision for any reason at 10 years was 92% (95% CI: 83-96). With re-revision for aseptic loosening as endpoint, the survival at 10 years was 99% (CI: 90-100).

INTERPRETATION

Femoral component revision with a third-generation cemented stem results in acceptable survival after medium-term follow-up. We recommend the use of this technique in femoral revisions with limited loss of bone stock.

Successful Outcomes Using Interlocking Prostheses for Periprosthetic Fractures with Loose Femoral Components

Periprosthetic femoral fractures with implant loosening are difficult to treat, especially when accompanied by severe bone loss. We report here the treatment outcomes of 4 patients (1 man, 3 women; age range 69-86 years) with periprosthetic femoral fractures and implant loosening after bipolar hemiarthroplasty. Fractures were classified according to the Vancouver classification as type B2 and B3, with adequate or compromised bone stock, respectively. One patient was initially treated conservatively but symptoms due to implant loosening persisted and revision surgery was required. All patients underwent revision using a long-stem cementless implant with interlocking screws as well as a cancellous allograft to augment the bone stock. At final follow-up (mean, 25 months), all patients had stable implant fixation, bony union of the fracture, and marked recovery of the proximal femoral bone stock through allograft use. This revision procedure achieved implant fixation and fracture healing with reconstitution of the femur even in the short term and even in cases with severe bone deficiency.

Mid-Term Outcomes and Complications with Cementless Distal Locking Hip Revision Stem with Hydroxyapatite Coating for Proximal Bone Defects and Fractures

We revised the first 100 revision total hip arthroplasties using a cementless distal locking revision stem conducted in our referral centre. Average follow-up was 9.2 years (range: 5.5-12 years). Harris Hip Score improved from 42.5 to 81.6, and none had thigh pain at last follow-up. No significant stress shielding, osteolysis, or radiologic loosening was found. All patients showed radiological evidence of secondary implant osseointegration. Overall survival was 97% with three patients being revised: two stem ruptures and one subsidence. We could trace these complications to technical errors. These findings suggest that a diaphyseal fixation of the revision stem with distal locking can provide the needed primary axial and rotational stability of the prosthesis. This would allow further bony ingrowth, enhanced by the hydroxyapatite coating.

Long term results with the interlocking uncemented long stem in revision hip arthroplasty: a mean 15-year follow-up

Stem fixation is difficult to achieve in severe proximal bone loss in revision hip surgery. In this study, we sought to present the results of distally-locked stem with screws (HUCKESTEP HIP stem) in 21 revision hips with mean follow-up period of 15 years. The preoperative mean Japanese Orthopaedic Association hip score had improved from 54 to 75 points. Further revisions were required for 2 stems, in one because of infection and the other because of screws fracture and subsidence. With removal of the stem for any reason as an end-point, the cumulative survival at 15 years was 90.4%. While this study had small number, the use of this interlocking stem for revision hips with extensive proximal bone defects provided satisfactory 15-year clinical and radiographic results.

Results of a tapered proximally-coated primary cementless stem for revision hip surgery

Nineteen patients (nineteen hips) who had undergone revision total hip arthroplasties using a proximally-coated primary cementless stem were evaluated to determine if a subset of revision arthroplasty patients could be identified where the use of this stem would be appropriate. Of these 19 revisions, 15 were performed for the second stage treatment of infection. The femoral bone deficiency was classified as Paprosky Type I in 6 hips and Type II in 13 hips. At a mean follow-up of 49 months, aseptic stem survivorship was 95% with one revision due to aseptic stem failure. The mean Harris hip scores had improved from a mean of 44 points pre-operatively to 89 points post-operatively. Intra-operatively, there was one complication which included a peri-prosthetic fracture distal to the stem which was treated with an allograft strut with cerclage wires. The authors believe that in type I or II femoral defects, the use of this specific cementless stem may be beneficial in the setting of a revision total hip arthroplasty.

Bone cement

The knowledge about the bone cement is of paramount importance to all Orthopaedic surgeons. Although the bone cement had been the gold standard in the field of joint replacement surgery, its use has somewhat decreased because of the advent of press-fit implants which encourages bone in growth. The shortcomings, side effects and toxicity of the bone cement are being addressed recently. More research is needed and continues in the field of nanoparticle additives, enhanced bone-cement interface etc.

Revision total hip replacement with a cemented long femoral component: minimum 9-year follow-up results

BACKGROUND

Surgical revision after failed total hip replacement is a technically challenging procedure. The aim of this study was to analyze the long-term results of revision total hip replacement using a cemented long femoral component and identify factors that influence the results.

METHODS

We retrospectively reviewed 34 hips in 33 patients who had undergone revision total hip replacement using a cemented long femoral component between 1994 and 2001. Hip function was evaluated according to the scoring system of the Japanese Orthopaedic Association. Radiographic examination was performed for evaluation of stem loosening, and its possible risk factors were investigated.

RESULTS

The mean follow-up duration was 11.3 years (9-15). Perioperative complications included intraoperative femoral cortex perforation (six hips, 18 %), dislocation (five hips, 15 %), deep venous thrombosis (one hip, 3 %) and postoperative periprosthetic fracture (one hip, 3 %). The mean preoperative Japanese Orthopaedic Association hip score was 50.3 ± 14.9 vs 78.2 ± 11.5 at the latest follow-up. The Kaplan-Meier survival rate at 15 years, calculated using radiological failure or re-revision of the femoral component for any reason as the end point, was 87 or 100 %, respectively. The failure-free survival rate for the subgroup with a good-quality cement mantle was significantly higher than that for the subgroup with poor quality (p = 0.033).

CONCLUSIONS

The quality of cementation was identified as a significant risk factor for further loosening. Revision total hip replacement using a cemented long femoral component yielded satisfactory long-term results in this series.

De-escalation exchange of loosened locked revision stems to a primary stem design: complications, stem fixation and bone reconstruction in 15 cases

INTRODUCTION

Femoral stem revision with a locked stem after total hip arthroplasties treats severe bone defects by favoring spontaneous bone reconstruction. Initially, once reconstruction was obtained, the temporary implant was to be replaced by a standard primary component. The use of locked stems has increased, but repeat revision with a short stem which is also called "de-escalation" has not been extensively studied.

HYPOTHESIS

Repeat revision of a locked stem with a short stem is not associated with any specific morbidity and does not affect the quality of reconstruction obtained, or fixation of the subsequent standard length primary design stem.

PATIENTS AND METHODS

Fifteen patients whose locked femoral stem was exchanged due to thigh pain and/or radiographic images showing failed osteointegration were analyzed. These 15 patients were all followed-up and evaluated by the Postel Merle d'Aubigné score. Progression of bone defects was evaluated using the Hofmann cortical index.

RESULTS

There were no difficulties extracting the locked stem and a standard length primary stem was inserted with no associated procedures or bone complications in any of the cases. At a mean follow-up of 55 months (36-84months), thigh pain had disappeared and the Postel Merle d'Aubigné score had increased from 12.6±2.9 (7-16) to 16.5±0.9 (15-18) (P=0.0001). The use of a locked femoral stem resulted in bone reconstruction in all cases, the Hofmann index increased from 30.5%±17.9% (12-71%) before insertion of the locked stem to 43.6%±25.6% (19-90%) at exchange (P<0.05). Bone reconstruction was durable after the exchange with a stable Hofmann index 43.7%±26.2% (17-92%) at the final follow-up (P=0.9). No recurrent loosening occurred.

DISCUSSION

Revision of a loosened locked femoral stem with a standard design primary stem does not result in any specific increased morbidity, or modify bone reconstruction obtained with the locked stem and results in stable fixation of a new standard length stem.

LEVEL OF EVIDENCE

IV: retrospective or historical series.

Distal locking stem for revision femoral loosening and peri-prosthetic fractures

Revision total hip arthroplasty in the setting of a large proximal femoral deficiency or a peri-prosthetic fracture remains a challenging problem. We describe the development, surgical technique and the use of cementless revision stems with distal inter-locking screws to provide immediate stability of the femoral implant. Results were assessed in a large multicentre French study conducted with the french hip and knee surgery society (SFHG). We retrospectively reviewed 725 revisions using interlocking stems from 14 French orthopaedic departments. Seven different stems were used in this series. In-patient records were retrieved, and in addition to demographic data the indication for revision, the preoperative and postoperative PMA and Harris hip scores were documented. The bone deficiency was classified on the basis of the French National Orthopaedic Meeting (SOFCOT) classification. Intraoperative complications and problems if any were retrieved from operative notes. Clinical status and radiographs at the final follow-up were evaluated, paying special attention to the metaphyseal filling index. Average follow-up was 4.5 years. As for the clinical results, the mean Harris hip score at last follow-up was 81. Therefore, it increased by an average of 31 points. Bone reconstruction was assessed on the cortico-medullary index in the metaphyseal area and at mid-shaft increasing from 36 to 45 and 54 to 63, respectively. Radiologically, 637 implants were stable, and 40 demonstrated subsidence. Forty-eight implants have been revised. We found a significant relation between the metaphyseal filling index, the stability of the stem and the quality of bone reconstruction. Results were analysed with respect to three groups of stems: group 1 was a straight, partially HA-coated implant; group 2 was a curved, fully HA-coated implant; and group 3 was a curved, partially-coated implant. Group 1 showed a significantly higher rate of failure when compared with the others types of implants. Group 2 had better functional results than group 3, which in turn reported better results than group 1. With regard to implant fixation, group 2 had significantly better results. Both groups 2 and 3 induced less thigh pain than group 1. The distal interlocking stem has shown promising results for femoral revisions. The advantages are initial axial and rotational stability and consistent bony in-growth owing to hydroxyapatite coating. Distal locked stems are mainly indicated to treat complex femoral revision with severe bone loss and peri-prosthetic fractures.

Comparative finite element analysis of the debonding process in different concepts of cemented hip implants

Damage accumulation in the cement mantle and debonding of the bone-cement interface are basic events that contribute to the long-term failure of cemented hip reconstructions. In this work, a numerical study with these two process coupled is presented. Previously uniform bone-cement interface mechanical properties were only considered. In this work, a new approach assuming nonuniform and random bone-cement interface mechanical properties was applied to investigate its effect on cement degradation. This methodology was also applied to simulate and compare the degradation process of the cement and bone-cement interface in three different concepts of design: Exeter, Charnley, and ABG II stems. Nonuniform and random mechanical properties of the bone-cement interface implied a simulation closer to reality. The predicted results showed that the cement deterioration and bone-cement interface debonding is different for each implant depending on the stem geometry. Lower cement deterioration was obtained for the Charnley stem and lower bone-cement interface debonding was predicted for the Exeter stem, while the highest deterioration (cement and bone-cement interface) was produced for the ABG II stem.

Primary aseptic revision of the femoral component of a cemented total hip arthroplasty using a cemented technique without bone graft

BACKGROUND

Primary revisions using cement without bone graft reconstruction are less frequently used because of their supposed higher failure rate. The results, in fact, depend on multiple parameters: number of prior revisions, cementing technique quality, and residual bone stock; these intricate factors are rarely taken together into account when analyzing this treatment method.

HYPOTHESIS

Femoral component fixation with cement can be a valid option in total hip arthroplasty primary revision.

OBJECTIVES

The objective of this investigation was to study the long-term results of cemented femoral stems in total hip arthroplasty primary revisions in terms of the quality of the cementing technique and the residual bone stock.

PATIENTS AND METHODS

This is a retrospective study of a series of 80-cemented primary femoral stems revised for aseptic loosening using a new-cemented femoral stem without bone graft. Seventy implants were analyzed at the longest follow-up. The Postel Merle D'Aubigné and the Harris Hip Scores were used for clinical assessment. The French Academy SOFCOT 99 bone loss grading system was used to classify preoperative bone compromise severity. The Barrack classification assessed the quality of the postoperative cementation. The radiographic study at the last follow-up sought signs of femoral implant loosening classified according to Harris.

RESULTS

The mean follow-up was 10 years and 10 months. The functional evaluation of the hip showed a significant overall gain (p<0.0001) after surgical revision. In our series, the existence of severe grade III or IV bone loss on the SOFCOT 99 classification exposed the patient to a significant risk of intraoperative complications (p=0.03). The grade III and IV femurs had a significantly higher risk (p=0.0001) of having type C or D cementation according to the Barrack classification. Type D cementation was a risk factor for significant iterative radiographic loosening (p=0.005) compared to A, B or C cementations. The 10-year survival rate of the femoral implant was 90% (95% confidence interval [95% CI]: 79.2-94.9%). This survival rate was significantly better (p=0.0016) for revisions with type A or B cementations on the Barrack scale (96% survival; 95% CI: 85.1-99%) than for type C or D (70% survival; 95% CI: 41.4-86.1%).

CONCLUSION

This study shows that revised cemented femoral stems without bone graft added are a valid therapeutic option in primary cemented total hip arthroplasty revisions provided that a good-quality cement technique can be achieved. Sufficient bone stock (SOFCOT 99 grade 0, I or II) was indispensable for good cementation.

LEVEL OF EVIDENCE

IV: therapeutic retrospective study.

Does increased bone-cement interface strength have negative consequences for bulk cement integrity? A finite element study

Implant loosening is one of the most important modes of failure of cemented total hip replacement. It may be related to the cement strength, cement-prosthesis interface, cement-bone interface, surgical technique, or stem design. The main purpose of this study is to investigate the effect of bone-cement interface mechanical properties on cement degradation. The computational methodology proposed herein combines a previously developed bone-cement interface damage model and an accumulative damage model for bulk cement. This has been applied to a finite element model of an Exeter cemented hip implant. A higher strength of the bone-cement interface due to a higher amount of interdigitated bone results in faster cement deterioration. Over time, damage both at the bone-cement interface and in the cement mantle worsens. Also, a larger debonded area was predicted proximally, as observed in clinical practice. We conclude that the computational model proposed herein allows a realistic simulation of the bone-cement interface debonding and cement degradation, being a useful tool in the design of this kind of medical devices.

One-stage cementless revision arthroplasty for infected hip replacements

We hypothesised that one-stage cementless revision hip arthroplasty may have advantages and a role in the treatment of selected patients with an infected hip replacement. We retrospectively reviewed all patients with an infected hip replacement treated with one-stage revision using cementless implants. Twelve patients were reviewed and followed up for at least three years (average: 7.2 years, range: 3.3-11.3 years) postoperatively. One recurrence of infection and one aseptic stem loosening were detected during follow-up. Grafted bone, which was used in eight patients, appeared to have united to host bone in all patients. The success rate of treatment was 83.3% when infection recurrence or component loosening were regarded as failure. One-stage revision hip arthroplasty using cementless implants appears to have a role in the treatment of carefully selected patients with an infected hip replacement if meticulous débridement is performed and appropriate antibiotics are properly used.

A prospective outcomes analysis of femoral component fixation in revision total hip arthroplasty

A prospective, surgeon-allocated, matched cohort analysis of patient outcomes compared cementless, modular metaphyseal and cemented femoral fixation used for revision total hip arthroplasty. First-time femoral revision operations (with and without acetabular revision) with Paprosky types I and II femoral bone stock were included. This series of 86 patients was matched for age, weight, diagnosis, Charnley class, Demand category, femoral bone stock, and outcome measures. At 8-year average follow-up (range, 4-13 years), there were no significant differences in visual analog pain scores (VAPS), Harris Hip Scores (HSS), and SF-36 Physical Function and Bodily Pain scores. One femoral rerevision (2.3%) occurred in the cementless group, and 2 (4.6%) occurred in the cemented group (P = .557). Five-year survivorship for femoral rerevision was 94% for patients with cementless, modular metaphyseal fixation and 92% for patients with cemented fixation. In this study, cementless, modular metaphyseal fixation and cemented femoral fixation were both successful at intermediate-term follow-up in Paprosky types I and II femoral bone (level of evidence: therapeutic study; level II, prospective comparative study).

Good results with an uncemented proximally HA-coated stem in hip revision surgery: 62 hips followed for 2-13 years

BACKGROUND AND PURPOSE

Proximal bone loss due to stress-shielding is a matter of concern after uncemented femoral hip revision. We have used short, proximally hydroxyapatite-coated prostheses in revision since 1989, and we now report the results.

METHODS

60 patients (62 hips) were revised because of aseptic loosening. Bone defects prior to revision were mostly of type II according to the Gustilo-Pasternak and Endo-Klinik classifications. Follow-up time was 73 (24-161) months. 9 patients had died before follow-up; 8 of these still had the stem in place. Clinical assessment was performed with the Harris hip score. Radiographs were evaluated for bone defects at revision, postoperative stem fixation, and periprosthetic bone remodeling.

RESULTS

Mean Harris hip score was 75 (30-100) points. There was no stem loosening or progressive subsidence. 8 patients had mild to moderate thigh pain. Osteolysis, present at revision, had diminished, partially or completely, in four-fifths of the hips at follow-up. 4 hips had required re-revision due to fracture or dislocation. The 6-year prosthesis survival rate was 95% (95% CI: 0.83-0.98).

INTERPRETATION

Uncemented revision with a short, proximally hydroxyapatite-coated prosthesis is a reliable procedure with encouraging results in the medium term if bone defects at revision are moderate.

Strontium-containing hydroxyapatite bioactive bone cement in revision hip arthroplasty

Clinical outcome of cemented implants to revision total hip replacement (THR) is not as satisfactory as primary THR, due to the loss of bone stock and normal trabecular pattern. This study evaluated a bioactive bone cement, strontium-containing hydroxyapatite (Sr-HA) bone cement, in a goat revision hip hemi-arthroplasty model, and compared outcomes with polymethylmethacrylate (PMMA) bone cement. Nine months after operation, significantly higher bonding strength was found in the Sr-HA group (3.36+/-1.84 MPa) than in the PMMA bone cement group (1.23+/-0.73 MPa). After detached from the femoral component, the surface of PMMA bone cement mantle was shown relatively smooth, whereas the surface of the Sr-HA bioactive bone cement mantle was uneven, by SEM observation. EDX analysis detected little calcium and no phosphorus on the surface of PMMA bone cement mantle, while high content of calcium (14.03%) and phosphorus (10.37%) was found on the surface of the Sr-HA bone cement mantle. Even higher content of calcium (17.37%) and phosphorus (10.84%) were detected in the concave area. Intimate contact between Sr-HA bioactive bone cement and bone was demonstrated by histological and SEM observation. New bone bonded to the surface of Sr-HA cement and grew along its surface. However, fibrous tissue was observed between PMMA bone cement and bone. The results showed good bioactivity of Sr-HA bioactive bone cement in this revision hip replacement model using goats. This in vivo study also suggested that Sr-HA bioactive bone cement was superior to PMMA bone cement in terms of bone-bonding strength. Use of bioactive bone cement may be a possible solution overcoming problems associated with the use of PMMA bone cement in revision hip replacement.

Extensively hydroxyapatite-coated stems in revision hip arthroplasty: A radiological mid-term follow-up study

Femoral revision surgery involves the placement of a stable stem and the regeneration of the damaged bone structure. We retrospectively reviewed 36 cases of femoral revision surgery in which an extensively hydroxyapatite-coated porous stem was implanted with a five-year minimum follow-up. Nine of the cases had type I defects, 12 had type II defects, six had III-A defects and nine had III-B defects. The mean follow-up was 7.7 years (range 5-11). No cases of revision surgery, subsidence or displacement were detected. In 35 cases the integration of the stem had been achieved, the bone structure had been restored and there was no fibrous interface visible between the implant and the bone. The fully hydroxyapatite-coated stems thus proved a valuable alternative for femoral revision surgery in mild and moderate bone defects. (Hip International 2005; 15: 38-45).

Revision total hip arthroplasty with use of a cemented femoral component. Results at a mean of ten years

BACKGROUND

Revision of the femoral component of a total hip replacement with use of cement has been associated with early mechanical failure due to aseptic loosening. The purpose of the present study was to determine the long-term survival after revision of the femoral component with cement and to identify factors that were predictive of failure.

METHODS

The results of 129 revision total hip arthroplasties that had been performed with use of a cemented femoral stem were reviewed to determine component survival. Ninety-seven hips that had been followed for a minimum of five years were included in survival analysis and tests of significance. Harris hip scores were used to quantify clinical outcomes. Clinical and surgical factors were analyzed to determine whether they were predictive of failure.

RESULTS

The mean Harris hip score improved from 52 points preoperatively to 71 points at the time of the most recent follow-up (p < 0.001). The ten-year survival rate was 91% with rerevision of the femoral component because of aseptic loosening as the end point and 71% with mechanical failure as the end point. Patients who were more than sixty years old had greater long-term component survival and less pain than younger patients did (p < 0.05). A good-quality postoperative cement mantle was associated with better long-term radiographic signs of fixation (p < 0.001). Poor femoral bone quality was associated with an increased rate of rerevision for aseptic loosening (p = 0.021).

CONCLUSIONS

Revision with use of a cemented femoral component remains an option for selected patients, with an acceptable ten-year survival rate and fair radiographic evidence of fixation. Our patients had acceptable clinical outcomes at ten years, and few had notable pain. The best results may be achieved in older patients (those who are sixty years old or more) with adequate bone stock who are managed with modern cementing techniques.

Cement penetration using a tibial punch cement pressurizer in total knee arthroplasty

This study describes a new tibial cement punch pressurizer to enhance cement penetration into the metaphyseal cancellous bone of the tibial plateau. Thirty knees of 15 patients undergoing simultaneous bilateral total knee arthroplasty (TKA) were randomly selected to receive the tibial cement punch pressurizer on one side, with the opposite side serving as control. Using computerized and radiographic evaluation of both knees 2 weeks postoperatively, the punch pressurizer achieved 132 times better penetration of the cement. The tibial punch cement pressurizer offers a simple technique to provide reliable cement penetration and tibial component fixation in TKA.

Experiences with the BiCONTACT revision stems with distal interlocking

The first consecutive 68 revision total hip arthroplasties of a cementless distal interlocking femoral stem (BiCONTACT; Aesculap AG, Tuttlingen, Germany) are included in this study. Average follow-up time was 40 months (range, 36-49 months). At follow-up evaluation, one patient had died, and one could not be located. The average Harris hip score improved from 60 points to 88 points. All cases showed radiographic evidence of a bone ingrown prosthesis, and no subsidence was seen. No osteolysis and no radiologic loosening were noted. No repeat revision was needed during the follow-up period. The results of the distal interlocking femoral stems (BiCONTACT) in cementless revision total hip arthroplasty were satisfactory. These findings suggest that a diaphyseal fixation of the revision femoral stem with distal interlocking screws can provide primary axial and rotational stability of the prosthesis in revision surgery.