Management of periprosthetic fracture following total knee arthroplasty- a retrospective study to decide when to fix or when to revise?

Revision total knee arthroplasty with periprosthetic distal femoral fracture

Treatment strategies for periprosthetic distal femoral fracture depend on the type of fracture, level with respect to the prosthesis, and prosthesis fixation. The usual treatment is internal fixation by nail or locking plate. This can be more difficult when the fracture is close to the joint, is destabilizing the prosthesis or is associated with reduced bone stock, and implant exchange should be considered, depending on the patient's health status. The aim is to obtain the fastest possible recovery while limiting complications and minimizing surgery time for often frail and elderly patients. The present study details the implant revision technique in periprosthetic distal femoral fracture, which requires experience in traumatology and prosthetic revision and material adapted to the situation. LEVEL OF EVIDENCE: V, expert opinion.

Revision surgery for periprosthetic fracture of distal femur after endoprosthetic replacement of knee joint following resection of osteosarcoma

Purpose

Periprosthetic fracture (PPF) is one of the severe complications in patients with osteosarcoma and carries the risk of limb loss. This study describes the characteristics, treatment strategies, and outcomes of this complication.

Methods

Patients were consecutively included who were treated at our institution between 2016 and 2020 with a PPF of distal femur. The treatment strategies included two types: 1) open reduction and internal fixation with plates and screws and 2) replacement with long-stem endoprosthesis and reinforcement with wire rope if necessary.

Results

A total of 11 patients (mean age 12.2 years (9-14)) were included, and the mean follow-up period was 36.5 (21-54) months. Most fractures were caused by direct or indirect trauma (n = 8), and others (n = 3) underwent PPF without obvious cause. The first type of treatment was performed on four patients, and the second type was performed on seven patients. The mean Musculoskeletal Tumor Society (MSTS) score was 20 (17-23). All patients recovered from the complication, and limb preservation could be achieved.

Conclusion

PPF is a big challenge for musculoskeletal oncologists, particularly in younger patients. Additionally, PPF poses a challenge for orthopedic surgeons, as limb preservation should be an important goal. Hence, internal fixation with plates and endoprosthetic replacement are optional treatment strategies based on fracture type and patient needs.

Machine Learning for Opportunistic Screening for Osteoporosis and Osteopenia Using Knee CT Scans

PURPOSE

To predict whether a patient has osteoporosis/osteopenia using the attenuation of trabecular bone obtained from knee computed tomography (CT) scans.

METHODS

Retrospective analysis of 273 patients who underwent contemporaneous knee CT scans and dual-energy X-ray absorptiometry (DXA) within 1 year. Volumetric segmentation of the trabecular bone of the distal femur, proximal tibia, patella, and proximal fibula was performed to obtain the bone CT attenuation. The data was randomly split into training/validation (78%) and test (22%) datasets and the performance in the test dataset were evaluated. The predictive properties of the CT attenuation of each bone to predict osteoporosis/osteopenia were assessed. Multivariable support vector machines (SVM) and random forest classifiers (RF) were used to predict osteoporosis/osteopenia.

RESULTS

Patients with a mean age (range) of 67.9 (50-87) years, 85% female were evaluated. Seventy-seven (28.2%) of patients had normal bone mineral density (BMD), 140 (51.3%) had osteopenia, and 56 (20.5%) had osteoporosis. The proximal tibia had the best predictive ability of all bones and a CT attenuation threshold of 96.0 Hounsfield Units (HU) had a sensitivity of .791, specificity of .706, and area under the curve (AUC) of .748. The AUC for the SVM with cubic kernel classifier (AUC = .912) was better than the RF classifier (AUC = .683, P < .001) and better than using the CT attenuation threshold of 96.0 HU at the proximal tibia (AUC = .748, P = .025).

CONCLUSIONS

Opportunistic screening for osteoporosis/osteopenia can be performed using knee CT scans. Multivariable machine learning models are more predictive than the CT attenuation of a single bone.

Should megaprosthesis implants be a viable option in elderly patients after distal femur and periprosthetic distal femur fractures?-a retrospective cohort study

Background

Distal femur fractures (DFF) and periprosthetic distal femur fractures (PDFF) in elderly patients are challenging to manage, often requiring the use of distal femur replacement (DFR) implants to manage severe bone loss and comminution. The study's main purpose was to analyze outcomes and complications of DFR implant after DFF or PDFF at our institution to understand the feasibility and reliability of this treatment considering a review of the current literature.

Methods

Fourteen consecutive patients undergoing total knee replacement with megaprosthesis implant from January 1st, 2017 to January 1st, 2021, at our institution were retrospectively analyzed. Inclusion criteria were age ≥65 years and DFF or PDFF after primary total knee arthroplasties (TKA) implantation. Patient-reported outcome measures (PROMs) such as Knee Society Score (KSS) and Oxford Knee Score (OKS) were analyzed, as well as radiographic pre- and post-operative imaging. Complications were recorded from the early postoperative period to the last follow-up.

Results

Nine patients were diagnosed with PDFF and five with DFF. At a mean follow-up of 30.7 months (range, 12 to 69 months), the mean KSS knee score was 79.5±11.2; the mean KSS function score was 69.0±17.9. The mean OKS was 31.6±8.9. The mean age at intervention was 82.1±7.6 years. Two delayed wound closures and one chronic prosthetic joint infection (PJI) were observed. No death was observed at the last follow-up.

Conclusions

Megaprosthesis implants could be a suitable option in elderly, arthritic patients diagnosed with complicated DFFs and PDFFs, allowing joint function preservation and a rapid return to daily activities. DFR remains an intervention burdened by devastating complications that must be considered in the treatment choice.

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.

Combination-type periprosthetic tibial fracture: Felix type (II+IV)A

Tibial periprosthetic fractures are rare but present a complicated problem for orthopaedic surgeons. Literature in relation to combination-type periprosthetic fractures is extremely scarce, and there is limited guidance available on its treatment. We report the case of a woman in her 60s, whose radiographs revealed a periprosthetic fracture of the tibia, which was a Felix type (II+IV)A fracture. The tibial tuberosity fragment was fixed with a cannulated cancellous screw. The fracture adjacent to the stem was managed conservatively as the prosthesis was stable. Follow-up radiographs revealed both fractures to have healed completely by 12 weeks. The patient returned to preinjury functional levels by 4 months. Our demonstrated treatment of a Felix type II+IV periprosthetic fracture could be a viable treatment option for such fractures.

New Classification for Periprosthetic Distal Femoral Fractures Based on Locked-Plate Fixation Following Total Knee Arthroplasty: A Multicenter Study

BACKGROUND

This study aimed to establish a new classification using locked-plate fixation for periprosthetic distal femoral fracture (PDFF) following total knee arthroplasty (TKA) and to determine when dual locked-plate fixation is necessary through defining this classification.

METHODS

One-hundred fifteen consecutive PDFFs that underwent operative treatment were reviewed from 2011 to 2019 with minimum 1-year follow-up. Most PDFFs were fixed with single or dual locked-plate fixations using the minimally invasive plate osteosynthesis technique. Based on preoperative radiographs, PDFFs were classified according to the level of main fracture line relative to the anterior flange of femoral component: type I and II, main fracture line located proximal and distal to the anterior flange; and type III, component instability regardless of fracture line requiring revisional TKA. Furthermore, type II fractures were subclassified based on the direction of fracture beak as follows: type II_L, lateral-beak; type II_M, medial-beak. The incidence, treatment methods, and complications were analyzed according to the classification.

RESULTS

Incidences of type I, II_L, II_M, and III were 64.4%, 8.7%, 24.3%, and 2.6%, respectively. Meanwhile, most PDFFs in type I and II were treated with lateral single locked-plate fixations, except for type II_M, which was treated with either single or dual locked-plate fixations. Overall complications were significantly higher in type II (28.9%) than in type I (10.8%, P = .019). In type II_M, bone union-related complications were significantly higher in single locked-plate fixation (50.0%) than in dual locked-plate fixation (5.6%; P = .013).

CONCLUSION

The new classification provides practical and obvious strategies for the treatment of PDFF following TKA using locked-plate fixation. For type II_M fracture, dual plate fixation is necessary to prevent fixation failure or nonunion.

Very Distal Femoral Periprosthetic Fractures: Replacement Versus Fixation: A Systematic Review

OBJECTIVES

To synthesize all-cause reoperations and complications data as well as secondary clinical and functional outcomes, after the management of very distal femur periprosthetic fractures (vDFPFs) in a geriatric patient population with either a distal femoral locking plate (DFLP) or distal femoral replacement (DFR).

DATA SOURCES

MEDLINE, Embase, and Web of Science were searched for English language articles from inception to March 16, 2020, in accordance to the PRISMA guidelines.

STUDY SELECTION

Studies reporting the management of vDFPFs in adults older than 65 years with either a DFLP or DFR were included. To ensure this review solely focused on very distal femoral periprosthetic fractures, only fractures of the following classifications were included: (1) Lewis and Rorabeck type II or III, (2) Su and Associates' Classification of Supracondylar Fractures of the Distal Femur type III, (3) Backstein et al type F2, and/or (4) Kim et al type II or III.

DATA EXTRACTION

Three reviewers independently extracted data from the included studies. Study validity was assessed using the methodological index for nonrandomized studies (MINORS), a quality assessment tool for nonrandomized controlled studies in surgery.

DATA SYNTHESIS

Twenty-five studies with 649 vDFPFs were included for analysis. There were 440 knees in the DFLP group (mean age range: 65.9-88.3 years) and 209 knees in the DFR group (mean age range: 71.0-84.8 years). Because of the literature's heterogeneity, the data were qualitatively synthesized.

CONCLUSIONS

vDFPFs in the elderly treated with DFR underwent fewer reoperations relative to DFLP (0%-45% vs. 0%-77%, respectively). Time to weight-bearing was observably shorter in DFR studies relative to DFLP studies. Functional outcomes and postoperative range of motion indicated a trend for DFLP knees to outperform DFR knees. Future research should include prospective studies and cost-effectiveness evaluations to better understand the utility of DFR for these fractures.

LEVEL OF EVIDENCE

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

A Review of Periprosthetic Tibial Fractures: Diagnosis and Treatment

Periprosthetic fracture occurring during or after total knee arthroplasty is a rare injury. Literature concerning periprosthetic tibial factures is sparse, and there is limited guidance for evidence-based management. This review aims to provide readers with an overview of the epidemiology, risk factors, and classification of these fractures. Management includes nonoperative treatment of nondisplaced fractures, fixation for those with stable implants, and revision for those with loose implants.