Proximal femoral replacement in non-oncologic patients undergoing revision total hip arthroplasty

Characteristics and Epidemiology of Megaprostheses Infections: A Systematic Review

BACKGROUND

Megaprostheses were first employed in oncological orthopedic surgery, but more recently, additional applications have arisen. These implants are not without any risks and device failure is quite frequent. The most feared complication is undoubtedly the implants' infection; however, the exact incidence is still unknown. This systematic review aims to estimate in the current literature the overall incidence of megaprosthesis infections and to investigate possible risk/protective factors.

METHODS

We conducted a systematic search for studies published from July 1971 to December 2023 using specific keywords. To be included, studies needed to report either the megaprosthesis anatomical site, and/or whether the megaprosthesis was coated, and/or the surgical indication as oncological or non-oncological reasons.

RESULTS

The initial literature search resulted in 1281 studies. We evaluated 10,456 patients and the overall infection rate was 12%. In cancer patients, the infection rate was 22%, while in non-oncological patients, this was 16% (trauma 12%, mechanical failure 17%, prosthetic joint infections 26%). The overall infection rates comparing coated and uncoated implants were 10% and 12.5%, respectively.

CONCLUSIONS

The number of megaprosthesis implants is increasing considerably. In traumatological patients, the infection rate is lower compared to all the other subgroups, while the infection rate remains higher in the cancer patient group. As these devices become more common, focused studies exploring epidemiological data, clinical outcomes, and long-term complications are needed to address the uncertainties in prevention and management.

Megaprosthesis use in Paprosky III/IV femoral defects in non-oncological patients: analysis of survival, clinical, and functional outcomes after an average follow-up of five years

PURPOSE

To determine the survival and patient-reported outcomes in non-oncological patients treated with proximal femoral resection (PFR) using MEG for femoral reconstruction.

MATERIALS AND METHODS

This retrospective study included 16 patients. Demographic variables and complications developed were analyzed. Clinical-functional outcomes were measured using the modified Harris score (mHSS), numeric Pain Rating Scale (NPRS) and Musculoskeletal Tumor Society (MSTS) score. MEG survival was estimated using a Kaplan-Meier survival analysis.

RESULTS

Average follow-up was 5 years (range, 1-9). The 75% of patients were overweight and women with an average age of 74.2 ± 5.9-years (BMI of 28.5 ± 4.2 kg/m2). The main cause of MEG was periprosthetic infection (43.7%). The 50% of patients had post-surgical complications regarding with MEG, being the most frequent seromas and MEG dislocation. Implant survival was 93.4% and 80.9% at 3 and 7 years of follow-up, respectively. The functional results at the end of the follow-up with respect to the pre-surgical state improved from 9.5 ± 2.6 to 3 ± 0.9 mean NPRS and 26.5 ± 6.8 to 69.5 ± 13.5 mean mHHS, p < 0.001, respectively. The mean MSTS score was 68.1% that these results were considered excellent.

CONCLUSIONS

The MEG for reconstruct III-IV femoral defects is a good therapeutic option that offers an acceptable clinical-functional result. Short-term and medium-term survival was greater than 80%. The most frequent complications are seromas and MEG dislocation. The use of constrained liner and abductor system reconstruction is essential to prevent the dislocation.

Factors Associated With Failure Following Proximal Femoral Replacement for Salvage Hip Surgery for Nononcologic Indications

BACKGROUND

Proximal femoral replacement (PFR) is used when extensive proximal femoral bone loss is encountered during revision total hip arthroplasty. However, further data on 5-to-10-year survivorship and predictors of failure are needed. Our aim was to assess the survivorship of contemporary PFRs used for nononcologic indications and determine factors associated with failure.

METHODS

A single-institution retrospective observational study was conducted between June 1, 2010 and August 31, 2021 for patients undergoing PFR for non-neoplastic indications. Patients were followed for a minimum of 6 months. Demographic, operative, clinical, and radiographic data were collected. Implant survivorship was determined via Kaplan-Meier analysis of 56 consecutive cemented PFRs in 50 patients.

RESULTS

At a mean follow-up of 4 years, the mean Oxford Hip Score was 36.2 and patient satisfaction was rated at an average of 4.7 of 5 on the Likert scale. Radiographic evidence of femoral-sided aseptic loosening was determined in 2 PFRs at a median of 9.6 years. The 5-year survivorship with all-cause reoperation and revision as end points was 83.2% (95% Confidence Interval [CI]: 70.1% to 91.0%) and 84.9% (95% CI: 72.0% to 92.2%), respectively. The 5-year survivorship was 92.3% (95% CI: 78.0% to 97.5%) for stem length > 90 mm compared to 68.4% (95% CI: 39.5% to 85.7%) for stem length ≤ 90 mm. A construct-to-stem length ratio (CSR) ≤ 1 was associated with a 91.7% (95% CI: 76.4% to 97.2%) survival, while a CSR > 1 was associated with a 73.6% (95% CI: 47.4% to 88.1%) survival.

CONCLUSION

A PFR stem length ≤ 90 mm and CSR > 1 were associated with increased rates of failure.

Megaprosthesis in Non-Oncologic Settings-A Systematic Review of the Literature

Modular megaprostheses (MPs) are commonly used after bone-tumor resection, but they can offer a limb salvage solution in massive bone defects. The aim of this systematic review of the Literature is to provide a comprehensive data collection concerning the use of MPs in non-oncologic cases, and to provide an overview of this topic, especially from an epidemiologic point of view. Three different databases (PubMed, Scopus, and Web of Science) were searched for relevant articles, and further references were obtained by cross-referencing. Sixty-nine studies met the inclusion criteria, reporting on cases of MP in non-oncologic cases. A total of 2598 MPs were retrieved. Among these, 1353 (52.1%) were distal femur MPs, 941 (36.2%) were proximal femur MPs, 29 (1.4%) were proximal tibia MPs and 259 (10.0%) were total femur MPs. Megaprostheses were most commonly used to treat periprosthetic fractures (1158 cases, 44.6%), in particular in the distal femur (859, 74.2%). Overall, complications were observed in 513 cases (19.7%). Type I (soft tissue failures) and type IV (infection) according to the Henderson classification were the most frequent (158 and 213, respectively). In conclusion, patients with severe post-traumatic deformities and/or significant bone loss who have had previous septic complications should be considered as oncologic patients, not because of the disease, but because of the limited therapeutic options available. The benefits of this treatment include relatively short operative times and immediate weight-bearing, thus making MP particularly attractive in the lower limb.

The major proximal femoral defects: megaprosthesis in non oncological patients - A case series

We identified 39 patients (23 female and 16 male) underwent hip revisions through mega-prosthesis. The most common causes were periprosthetic fractures, periprosthetic osteolysis and consequences of infected arthroplasty. The average follow-up was 5 years (2.1 to 6.5), and average age was 69 years (47 to 78). At the final follow-up all the implants resulted functional and osteointegrated. The Merle D'Aubignè and Postel hip rating scale was used for the evaluation, better results were observed in periprosthetic fractures. Postoperative complications occurred in eight patients. Thus, megaprosthesis were a reasonable surgical option in the management of major femoral defects.

[Strategies for stem revision : Surgery planning, implant removal and reimplantation]

BACKGROUND AND PLANNING

Femoral revision represents a challenging procedure in its surgical planning and technical execution. The results are mainly dependent on the bone loss present, the quality of the implant removal and the choice of revision system. Patient-specific factors such as age, comorbidities, bone quality or even the localization of the cement have a decisive influence on the surgical strategy. Appropriate preoperative preparation, including the presence of the necessary special instruments, which are essential for gentle implant removal, is indispensable to achieve the best possible result.

THERAPY

A bone-sparing implant removal can be particularly challenging, especially in the case of well-fixed stems and cement residues, which may extend far beyond the isthmus. In such situations, a transfemoral approach should be considered. Cementless reimplantation using modular or non-modular titanium stems is currently the preferred treatment of choice for most revisions. In elderly, low-demand patients or with poor bone quality, cemented revision remains a good alternative treatment option.

Modern Proximal Femoral Replacement in Revision Total Hip Arthroplasty for Nononcologic Indications

BACKGROUND

Advances in surgical technique and prosthesis design have expanded the non-neoplastic indications for proximal femoral replacement (PFR) to include fracture nonunion, periprosthetic fracture, and severe bone loss in the setting of revision total hip arthroplasty (THA). The purpose of this study is to assess outcomes of PFRs used for nononcologic indications.

METHODS

A single-institution, retrospective, cohort survey study was conducted between August 2015-February 2020 of consecutive patients undergoing PFR for nononcologic indications in revision THA. Patient demographics, surgical variables, complications, and revision procedures were collected. Patient satisfaction and Oxford Hip scores were assessed via a telephone questionnaire. Implant survivorship was estimated using the Kaplan-Meier method.

RESULTS

In total, 24 patients (27 PFRs) were available for analysis with an average age of 69.3 ± 12.9 years (range: 37-90). The average number of operations prior to PFR implantation was 3.1 ± 2.1 (range: 0-7). At a mean follow-up of 2.4 years (range: 0.5-5.1), the mean Oxford Hip Score was 31.7 ± 10.2, and mean patient satisfaction was 4.9/5. Six patients (20.7%) experienced a postoperative complication, with dislocation occurring in three patients (10.3%). None of the patients with dual mobility articulations (n = 4) had dislocation. Three-year survivorship was 85.2% (95% CI 71.8%-98.6%) with all-cause reoperations as the endpoint and 100% (95% CI 100.0%-100.0%) with revision for aseptic loosening as the endpoint.

CONCLUSION

The current study demonstrates excellent short-term survivorship, satisfactory patient-reported outcomes, and high patient satisfaction following PFR for nononcologic indications during revision THA utilizing modern techniques. The most common mode of failure was dislocation requiring reoperation with revision to constrained acetabular components.

Novel Design of the Compound Sleeve and Stem Prosthesis for Treatment of Proximal Femur Bone Defects Based on Topology Optimization

The loosening of traditional prosthetics is among the leading causes of surgical failure of proximal femoral bone defects. A novel compound sleeve and stem prosthesis was designed using an optimization methodology that combined an octet-truss porous structure with density-based topology optimization to improve stability, promote bone ingrowth, and enhance biomechanical properties. Biomechanical changes were assessed using finite element analysis. The distribution of stress, the strain energy density, and the relative micromotion in the optimized group were considered. The optimized sleeve prosthesis achieved a 31.5% weight reduction. The maximum stresses in the optimized group were observed to decrease by 30.33 and 4.74% at the back sleeve and neck part of stem prosthesis, with a 29.52% increase in the femur, respectively. The average stress in most selected regions in the optimized group was significantly greater than that in the original group (p &lt; 0.05). The maximum relative micromotion decreased by 15.18% (from 63.9 to 54.2 μm) in the optimized group. The novel designed compound sleeve and stem prosthesis could effectively improve the biomechanical performance of next-generation prosthetics and provide a microenvironment for bone ingrowth. The presented method could serve as a model for clinical practice and a platform for future orthopedic surgery applications.

Proximal femoral replacement using the direct anterior approach to the hip

OBJECTIVE

Proximal femoral replacement (PFR) is a salvage procedure originally developed for reconstruction after resection of sarcomas and metastatic cancer. These techniques can also be adapted for the treatment of non-oncologic reconstruction for cases involving massive proximal bone loss. The direct anterior approach (DAA) is readily utilized for revision total hip arthroplasty (THA), but there have been few reports of its use for proximal femoral replacement.

INDICATIONS

Aseptic, septic femoral implant loosening, periprosthetic femoral fracture, oncologic lesions of the proximal femur. The most common indication for non-oncologic proximal femoral placement is a severe femoral defect Paprosky IIIB or IV.

CONTRAINDICATIONS

Infection.

SURGICAL TECHNIQUE

In contrast to conventional DAA approaches and extensions, we recommend starting the approach 3 cm lateral to the anterior superior iliac spine and performing a straight incision directed towards the fibular head. After identification and incision of the tensor fasciae lata proximally and the lateral mobilization of the iliotibial tract distally, the vastus lateralis muscle can be retracted medially as far as needed. Special care should be taken to avoid injuries to the branches of the femoral nerve innervating the vastus lateralis muscle. If required, the distal extension of the DAA can continue all the way to the knee to allow implantation of a total femoral replacement. The level of the femoral resection is detected with an x‑ray. In accordance with preoperative planning, the proximal femur is resected. Ream and broach the distal femoral fragment to the femoral canal. With trial implants in place, leg length, anteversion of the implant and hip stability are evaluated. It is crucial to provide robust reattachment of the abductor muscles to the PFR prosthesis. Mesh reinforcement can be used to reinforce the muscular attachment if necessary.

POSTOPERATIVE MANAGEMENT

We typically use no hip precautions other than to limit combined external rotation and extension for 6 weeks. In most cases, full weight bearing is possible after surgery.

RESULTS

A PFR was performed in 16 patients (mean age: 55.1 years; range 17-84 years) using an extension of the DAA. The indication was primary bone sarcoma in 7 patients, metastatic lesion in 6 patients and massive periprosthetic femoral bone loss in 3 patients. Complications related to the surgery occurred in 2 patients (both were dislocation). Overall, 1 patient required reoperation and 1 patient died because of his disease. Mean follow-up was 34.5 months.

Dual mobility cups associated with proximal femoral replacement in nontumoral indications: Results and complications

INTRODUCTION

Reconstruction of extensive proximal femoral bone loss is a major challenge during total hip arthroplasty (THA). Proximal femoral replacement (PFR), initially used for bone tumors, is an alternative to allograft-prosthetic composite reconstruction. However, PFRs present a high complication rate, particularly related to dislocation. Moreover, dual mobility cups (DMCs) are effective in preventing dislocation, and no study has yet assessed their association with PFRs. Therefore, the aim of this study was to assess the dislocation and complication rates in THA using PFRs with DMCs.

HYPOTHESIS

The use of a DMC decreases the dislocation rate associated with PFRs in nontumoral indications.

METHODS

From 2008 to 2017, 66 PFRs associated with a DMC (40 women, mean age=71 years [26-94]) were included in our total joint registry and retrospectively reviewed. The main indications were complex periprosthetic and pertrochanteric fractures (26 THAs, 40%), aseptic loosening (22 THAs, 33%) and periprosthetic joint infections (18 THAs, 27%). A single design of PFR implant was used (Global Modular Replacement System (GMRS), Stryker, Mahwah, NJ, USA) with an uncemented stem in 54 THAs (82%).

RESULTS

Eighteen complications (27%) were reported at a mean follow-up of 4.6 years [2-10]: 5 dislocations (7.5%), 9 periprosthetic joint infections (13.6%), 2 aseptic loosening (3%) and 2 femur fractures (3%). Overall survivorship at 5 years was 72% (95% CI: 58-82). Survivorship free from dislocation was 94% (95% CI: 85-98) at 1 year. The mean Harris Hip Score was 70±16.4 [26-100] at latest follow-up.

CONCLUSION

The use of DMCs limits the risk of PFR dislocation, in comparison to other series in the literature that used large femoral heads, without compromising implant survivorship. In addition, DMCs make it possible to overcome the potential risks of mechanical failure associated with constrained acetabular components.

LEVEL OF EVIDENCE

IV; retrospective cohort.

Proximal femoral replacement for non-neoplastic conditions: a systematic review on current outcomes

Proximal femoral replacement (PFR) is a well-established treatment for neoplasia of the proximal femur. The use of this surgical technique for non-neoplastic conditions has increased over the years. We carried out a systematic review of the literature to study the indications, complications, and functional results when PFR is used for non-neoplastic conditions. Twenty-seven studies were included in the review with a total of 828 PFRs with a mean follow-up of 50 months (range 1-225 months). The main indications were infection (28%), periprosthetic fracture (27%), aseptic loosening (22%), and fracture (16%). The rate of reoperation was 20.3% overall. The overall revision rate was 15.4%. The main complications were dislocation (10.2%) and infection (7.3%). After 2010, the rates of reoperation (25.5% versus 18.2%), loosening (9.4% versus 3.2%), and dislocation (15.7% versus 7.9%) were lower than before 2010. The 30-day mortality ranged from 0% to 9%. The hip function scores improved post-surgery. In conclusion, the use of PFR in non-neoplastic conditions remains a marginal tool, associated with low direct mortality and high complication rates, but we expect its use to increase in the near future.

Clinical and radiological outcomes of combined modular prothesis and cortical strut for revision proximal femur in giant cell tumor of bone patients

BACKGROUND

Femoral bone deficiency is a challenging problem in revision proximal femoral replacement. The purpose of this study is to evaluate the clinical and radiological outcomes of revision proximal femoral replacement as a salvage treatment for severe bone loss after oncologic proximal replacement surgery in patient with benign giant cell tumor of bone.

METHODS

16 patients (6 men and 10 women) were included in this retrospective study, with a mean age of 46.6 year at the time of revision surgery. All patients underwent revision proximal femoral replacement with the use of modular prosthesis and cortical strut allografts. The modified Harris Hip Score, Short Form 36, and musculoskeletal Tumor Society Score were used for patient evaluation. Regular follow-up was performed to evaluate the recurrence and metastases rate, limb function, and long-term complications of patients.

RESULTS

The average follow-up was 46.3 months (range, 26-75 months), during which there was no local recurrence and metastases of patient. At the latest follow-up, the mean modified Harris Hip Score was 70.6 points, which was significantly improved compared with that of preoperative (p < 0.05). The final follow-up results of Short Form 36, Musculoskeletal Tumor Society Score, and limb-length discrepancy were also significantly improved compared to that of preoperative (p < 0.05). At the latest follow-up, the implanted femoral stems were all stable and all cortical strut allografts were also incorporated to their own bone.

CONCLUSION

Using modular prosthesis and cortical strut allografts in revision, proximal femur replacement is an acceptable procedure for relatively young patient with severe proximal femoral bone loss after oncologic surgery with benign giant cell tumor of bone. More attentions should be paid to reduce the risk of complications in these complex reconstructions.

Survivorship and clinical outcomes of proximal femoral replacement in non-neoplastic primary and revision total hip arthroplasty: a systematic review

BACKGROUND

Several studies have evaluated the survivorship and clinical outcomes of proximal femoral replacement (PFR) in complex primary and revision total hip arthroplasty with severe proximal femoral bone loss; however, there remains no consensus on the overall performance of this implant. We therefore performed a systematic review of the literature in order to examine survivorship and complication rates of PFR usage.

METHODS

A systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed. A comprehensive search of PubMed, MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews was conducted for English articles using various combinations of keywords.

RESULTS

In all, 18 articles met the inclusion criteria. A total of 578 PFR were implanted. The all-cause reoperation-free survivorship was 76.6%. The overall complication rate was 27.2%. Dislocation was the most common complication observed and the most frequent reason for reoperation with an incidence of 12.8 and 7.6%, respectively. Infection after PFR had an incidence of 7.6% and a reoperation rate of 6.4%. The reoperation rate for aseptic loosening of the implant was 5.9%. Overall, patients had improved outcomes as documented by postoperative hip scores.

CONCLUSION

PFR usage have a relatively high complication rate, however, it remains an efficacious treatment option in elderly patients with osteoporotic bone affected by severe proximal femoral bone loss. Modular designs have shown reduced dislocations rate and higher survivorship free from dislocation. However, PFR should only be used as salvage procedure when no other reconstruction options are available.

Different outcomes after proximal femoral replacement in oncologic and failed revision arthroplasty patients - a retrospective cohort study

Background

Proximal femoral replacement (PFR) is a technically demanding procedure commonly performed to restore extensive, oncological or non-oncological bone defects in a severely debilitated patient collective. Depending on different indications, a varying outcome has been reported. The aim of the study was to assess the functional outcomes and complication rates of PFR with the modular Munich-Luebeck (MML) femoral megaprosthesis (ESKA/Orthodynamics, Luebeck, Germany), and to highlight outcome differences in patients treated for failed revision total hip arthroplasty (THA) or malignant bone disease.

Methods

A retrospective review of patients treated with PFR for failed THA or malignant tumor disease between 2000 and 2012 was performed. Patient satisfaction, functional outcome (VAS, SF-12, MSTS, WOMAC, TESS), complications and failure types (Henderson’s failure classification) were assessed. A Kaplan-Meier analysis determined implant survival.

Results

Fifty-eight patients (age: 69.9 years, BMI: 26.7 kg/m², mean follow-up: 66 months) were included. The mean SF-12 (physical / mental) was 37.9 / 48.4. MSTS averaged 68% at final follow-up, while mean WOMAC and TESS scored 37.8 and 59.5. TESS and WOMAC scores demonstrated significantly worse outcomes in the revision group (RG) compared to the tumor group (TG). Overall complication rate was 43.1%, and dislocation was the most common complication (27.6%). Implant survival rates were 83% (RG) and 85% (TG; p = n.s.) at 5 years, while 10-year survival was 57% (RG) and 85% (TG, p < 0.05).

Conclusions

PFR is a salvage procedure for restoration of mechanical integrity and limb preservation after extensive bone loss. Complications rates are considerably high.

Functional outcomes and 10-year implant survival rate were worse in the RG compared to the TG. Strict indications and disease-specific patient education are essential in preoperative planning and prognosis.

Novel Cemented Technique for Trochanteric Fixation and Reconstruction of the Abductor Mechanism in Proximal and Total Femoral Arthroplasty: An Observational Study

Background

Little evidence exists regarding the clinical outcomes of cemented trochanteric fixation for abductor mechanism reconstruction in proximal or total femoral replacements. Clinical outcomes were assessed for a novel cemented technique for trochanteric fixation in femoral megaprostheses.

Methods

A descriptive series of 13 patients who underwent proximal or total femoral arthroplasty from 2016 to 2019 were reviewed. Radiographic trochanteric displacement >1 cm defined construct failure. A Kaplan-Meier survival analysis was performed to determine survival rates for these cemented constructs. Demographic information was obtained to better characterize the patient population in whom this technique was used.

Results

Eleven patients were included (age = 63.6 years; 45.4% females; body mass index = 31.7). Mean time to final radiographic follow-up was 73.8 weeks. Three of 11 (27.2%) patients had construct failure. Overall, survival at 1 year was 81.8%. At 2 years, survival of cemented constructs was 65.5%. More construct failures occurred in patients who sustained a postoperative dislocation than in those who did not (P = .05).

Conclusions

This novel cemented trochanteric fixation technique for reconstruction of the abductor mechanism in femoral megaprostheses had 81.8% survival at 1 year postoperatively. While longitudinal comparative studies with larger samples are needed, the cemented technique may provide a viable alternative to traditional cementless methods of trochanteric fixation. Increased construct failure rates after postoperative dislocation highlight the importance of robust abductor reconstruction in these implants.

Proximal femoral reconstruction with modular megaprostheses in non-oncological patients

Introduction

Multiple revision hip arthroplasties and critical trauma might cause severe bone loss that requires proximal femoral replacement (PFR). The aim of this retrospective study was to analyse complication- and revision-free survivals of patients who received modular megaprostheses in an attempt to reconstruct massive non-neoplastic bone defects of the proximal femur.

Questions/purposes

(1) What were general complication rates and revision-free survivals following PFR? (2) What is the incidence of complication specific survivals? (3) What were risk factors leading to a diminished PFR survival?

Materials and methods

Twenty-eight patients with sufficient follow-up after receiving a modular proximal femoral megaprosthesis were identified. The indications for PFR included prosthetic joint infection (PJI), periprosthetic fracture, aseptic loosening, non-union and critical femoral fracture. Complications were grouped according to the ISOLS-classification of segmental endoprosthetic failure by Henderson et al.

Results

Overall, the complication-free survival was 64.3% at one year, 43.2% at five years and 38.4% at ten years, with 16 patients (57%) suffering at least one complication. Complications were dislocation in eight patients (29%), PJI in 6 patients (21%), periprosthetic fracture in five patients (18%), and aseptic loosening in six patients (21%). Prosthesis stem cementation showed a lower risk for revision in a cox proportional hazard model (95% CI 0.04–0.93, HR 0.2, p = 0.04).

Conclusion

PFR with modular megaprostheses represents a viable last resort treatment with high complication rates for patients with severe proximal femoral bone loss due to failed arthroplasty or critical fractures. In revision arthroplasty settings, PFR cementation should be advocated in cases of impaired bone quality.

Minimum ten-year results in revision total hip arthroplasty using titanium fully porous long stem

PURPOSE

The fully porous long stem could be used for diaphyseal locking and achieve bypass fixation in revision total hip arthroplasty (THA). This study evaluated long-term results for fully porous long stems made of titanium alloy in revision THA.

METHODS

Between 2003 and 2010, 45 consecutive femoral revisions were performed using fully porous long stems. Thirty-eight hips had complete clinical and radiographic data for a mean of 13.8 years (range, 10-16.7 years). Femoral bone loss was Paprosky type II in 14 hips, type IIIA in 18 hips, and type IIIB in six hips. Clinical results were analyzed using the Merle d'Aubigné and Postel scoring system. Femoral stress shielding was graded. Radiological loosening of the femoral component was evaluated. Kaplan-Meier survival analysis was performed with revision for any reason as the end-point.

RESULTS

Mean Merle d'Aubigné and Postel score improved significantly from 10.7 before revision to 14.5 at latest follow-up (p < 0.001). Third-degree stress shielding was found in seven hips, and fourth degree in 11 hips. Radiological femoral loosening occurred in one hip, which was revised. Another hip was revised for stem fracture. Kaplan-Meier cumulative survival rate was 94.7% at both ten and 15 years.

CONCLUSION

Although stress shielding is a concern with fully porous stems, this stem was useful in revision THA and provided satisfactory long-term results in hips with Paprosky types II, IIIA, and IIIB.

Interlocking reconstruction-mode stem-sideplates preserve at-risk hips with short residual proximal femora

AIMS

We have evaluated the survivorship, outcomes, and failures of an interlocking, reconstruction-mode stem-sideplate implant used to preserve the native hip joint and achieve proximal fixation when there is little residual femur during large endoprosthetic reconstruction of the distal femur.

METHODS

A total of 14 patients underwent primary or revision reconstruction of a large femoral defect with a short remaining proximal femur using an interlocking, reconstruction-mode stem-sideplate for fixation after oncological distal femoral and diaphyseal resections. The implant was attached to a standard endoprosthetic reconstruction system. The implant was attached to a standard endoprosthetic reconstruction system. None of the femoral revisions were amenable to standard cemented or uncemented stem fixation. Patient and disease characteristics, surgical history, final ambulatory status, and Musculoskeletal Tumor Society (MSTS) score were recorded. The percentage of proximal femur remaining was calculated from follow-up radiographs.

RESULTS

All 14 at-risk native hip joints were preserved at a mean final follow-up of 6.0 years (SD 3.7), despite a short residual femur, often after proximal osteotomies through the lesser trochanter. Overall, 13 of 14 stems had long-term successful fixation. Eight patients required no reoperation. Three patients required reoperation due to implant-related issues, and three patients required reoperation for wound healing problems or infection. There were no dislocations or fractures. At final follow-up the mean MSTS score was 24.9 (SD 4.1). Nine patients required no ambulation aids, and only one had a Trendelenburg gait.

CONCLUSION

This interlocking, reconstruction-mode stem-sideplate reliably preserves native hip joint anatomy and function after large femoral resection with a short remaining proximal femur, both in the primary and revision setting. This is particularly important for preventing or delaying total femoral arthroplasty in young patients after oncological reconstruction. Hip abductor strength and function could be maintained by this method, and the risk of dislocation eliminated. The success of this technique in this modest series should be verified in a larger collaborative study and will be of interest to revision surgeons and oncologists. Cite this article: Bone Joint J 2021;103-B(2):398-404.

Hospital Resource Utilization Associated With Endoprosthetic Reconstruction Versus Primary Arthroplasty

Endoprosthetic reconstructions of the hip and knee are currently reimbursed as primary hip and knee arthroplasty according to Current Procedural Terminology (CPT) coding guidelines. The purpose of this study was to compare hospital resources consumed by patients undergoing endoprosthetic reconstruction with those consumed by patients undergoing primary arthroplasty. The authors' hypothesis was that the former group carries more comorbidities, experiences longer length of stay (LOS), and has greater resource consumption. A retrospective review was performed of 61 patients undergoing endoprosthetic reconstruction and 745 patients undergoing primary hip or knee arthroplasty between 2015 and 2018 at a single institution. Demographic, clinical, and financial data were compared. The Charlson Comorbidity Index (CCI) was used to measure patients' health status and identify comorbidities associated with prolonged LOS through linear regression analysis. Patients who underwent endoprosthetic reconstruction had a greater than 3.5 times average LOS compared with primary arthroplasty patients: 10.81 days vs 2.94 days (P<.01). They demonstrated a higher mean CCI, higher rates of malignancy and pulmonary disease, and a wider age range. Their mean cost of care totaled $73,730.29, compared with $24,940.84 imposed by primary arthroplasty patients (P<.01). Significant predictors of LOS were malignancy status (metastatic or localized) and age younger than 50 years, with increased LOS being associated with increased cost. Patients undergoing endoprosthetic reconstruction of the hip and knee represent a fundamentally different patient population than primary arthroplasty patients based on comorbidities, variability in health status, and surgical indications. They have higher comorbidity scores and longer hospitalizations and consume more financial resources than primary arthroplasty patients. [Orthopedics. 2021;44(1):e73-e79.].

A modified technique of mega prosthesis revision on non-neoplastic patient: Case report

Introduction

Mega prosthesis is mainly used for the treatment of the oncologic patient whose limb underwent salvage surgery that caused the limb to lose significant bone or soft tissue. In recent years, mega prosthesis can also be used to treat non-oncologic patients.

Presentation of case

We presented a case of a 40-year-old male with chief complain of pain on the right knee 5 months before admission. Four years previously, the patient sustained motor vehicle accident that fractured his head of femur dan distal femur. He underwent 2-staged surgery for his femoral head and distal femur. However, he presented a year later with signs of non-union and finally underwent mega prosthesis surgery on his distal femur. During his follow up, he experienced a fracture on his prosthesis 3 years later and was referred to our institution. Physical examination shows deformity and slight varus on the right knee, and limited range of motion. The patient then underwent implant revisions.

Discussion

After 12 months of post revision surgery follow-up, the patient was able to walk independently. Our patient has not had any sign or episode of failure after the follow up for 12 months. According to literature, the incidence of failure is mostly at 48-72 months post implantation.

Conclusion

The problem for this patient maybe caused by the mechanical fatigue of the implant due to stress addressed to the implant. Our current technique of revisions procedure hopefully will enhance the power of the mega prosthesis for further usage.

Survivorship of Megaprostheses in Revision Hip and Knee Arthroplasty for Septic and Aseptic Indications: A Retrospective, Multicenter Study With Minimum 2-Year Follow-Up

Background

The use of megaprostheses in nononcologic patients has been associated with complication rates greater than 50%. In patients with prior periprosthetic joint infection (PJI) with subsequent two-stage reimplantation, this complication rate may be even higher. This study was to investigate the outcomes of megaprostheses in nononcologic patients undergoing revision hip/knee arthroplasty.

Methods

We retrospectively studied patients who underwent megaprosthesis replacements from 1999 to 2017 at 5 hospitals with minimum 24 months of follow-up. Patients were stratified based on history of prior PJI (septic vs aseptic) and location of the megaprosthesis (the hip or knee). Postoperative complications were classified as soft-tissue failure, aseptic loosening, structural failure, and infection.

Results

Of the 42 patients, 19 were in the septic cohort and 23 were in the aseptic cohort. The overall complication rate was 28.6%. Complication rates for the septic and aseptic cohorts were 32% and 26%, respectively (P = .74). By anatomic location, there were 2 of 13 (15%) and 10 of 29 (34%) complications in the hip and knee groups, respectively (P = .28). In the septic cohort, there were no (0%) complications in the hip group and 6 of 14 (43%) complications in the knee group (P = .13), all due to infection. In the aseptic cohort, there were 2 of 8 (25%) and 4 of 15 (27%) complications in the hip and knee groups, respectively (P = 1.0).

Conclusions

There is no difference in the postoperative complication rates between the septic or aseptic cohorts undergoing revision hip or knee megaprosthesis replacements. In patients with prior PJI, proximal femoral replacements have improved short-term survivorship compared with distal femoral or proximal tibial replacements.