Radiographic and Clinical Outcomes of Periprosthetic Distal Femur Fractures Treated With Open Reduction Internal Fixation

Clinical and Radiographic Results of a Retrograde Nail-Washer Combination Versus Lateral Locked Plating for Distal Femur Fractures

OBJECTIVES

The objective of this study was to report outcomes of the Retrograde Femoral Nail-Advanced with Lateral Attachment Washer (RFNA-LAW) (Synthes, Paoli, PA) compared with laterally locked plates (LLP) when treating AO/OTA type 33 distal femoral fractures.

METHODS

DESIGN

Retrospective chart review.

SETTING

Single, academic, Level-1 Trauma Center.

PATIENT SELECTION CRITERIA

All adult patients who had fixation of an AO/OTA type 33 distal femoral fracture with the RFNA-LAW combination or LLP from 2018 to 2023 with follow-up to union or a minimum of 1 year.

OUTCOME MEASURES AND COMPARISONS

The main outcome measure was union. Secondary outcomes included implant failure, infection, and alignment immediately postoperatively and at final follow-up. Primary and secondary outcome measures were compared between the RFNA-LAW and LLP groups.

RESULTS

Forty-eight patients (19 female) with a mean age of 56 years (range 19-94 years) were in the RFNA-LAW group. Fifty-three patients (29 female) with a mean age of 66 years (24-91 years) were in the LLP group. There were no significant differences when comparing body mass index, diabetes, smoking status, mechanism of injury, or fracture classification between groups ( P > 0.05). There was no difference in immediate, postoperative alignment ( P = 0.49). When comparing anatomic lateral distal femoral angle measurements at final follow-up, there was significantly more malalignment in the LLP group ( P = 0.005). There were 8 implant failures (15%) in the LLP group compared with 1 in the RFNA-LAW group (2%) ( P = 0.02). There were 14 reoperations (26%) in the LLP group compared with 4 (8%) in the RFNA-LAW group ( P = 0.02).

CONCLUSIONS

The Retrograde Nail Advanced-Lateral Attachment Washer combination demonstrated a high union rate when treating complex fractures of the distal femur. When compared with lateral locked plating, this implant combination demonstrated significantly lower rates of nonunion and reoperation.

LEVEL OF EVIDENCE

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

Weightbearing versus non-weight bearing in geriatric distal femoral fractures: a systematic review and meta-analysis

BACKGROUND

Demographics of patients who sustain geriatric distal femoral fractures (DFF) match those of patients with neck-of-femur fractures but have limited evidence with which to support post-operative weightbearing protocols.

PURPOSE

This systematic review sought to identify any difference in outcomes for elderly patients with DFF who were allowed early versus delayed weightbearing postoperatively.

METHODS

DATA SOURCES: PubMed, Medline, Embase and The Cochrane Library, reference lists of retrieved articles.

STUDY SELECTION

English language papers published between January 2010 and February 2023 with AO-OTA type 33A, B and C femoral fractures as well as Lewis and Rorabeck Type I and II periprosthetic DFF surgically treated with either a lateral locking plate or retrograde intramedullary nail and an average patient age of ≥ 60 years.

DATA EXTRACTION

Studies were assessed for inclusion by two authors and quality was assessed using the MINORS tool.

DATA SYNTHESIS

Sixteen studies were included, Meta-analysis of non-union, malunion, infection, delayed union and implant complications was performed using Microsoft Excel and the MetaXL extension. The data on return to mobility were presented in narrative form. The analyses demonstrated no difference between the early and delayed weightbearing groups.

CONCLUSIONS

There are no significant differences in complication rates between early versus delayed weightbearing after surgery for DFF in an elderly population. The study results are limited by high heterogeneity and low-quality studies. High quality, prospective studies are needed to determine the ideal postoperative weightbearing protocol.

LEVEL OF EVIDENCE

Level III, Systematic Review and Meta-analysis of Level III studies. International Prospective Register of Systematic Reviews registration-Prospero CRD42022371460.

Comparative study of retrograde intramedullary nailing versus locking extramedullary plating in complete articular fractures with metaphyseal comminution of the distal femur

INTRODUCTION

Fractures of the distal femur with metaphyseal comminution and complete intra-articular involvement (AO/OTA classifications 33C2 and 33C3) present challenges for reduction and fixation. However, an optimal fixation method remains unknown. This study aimed to compare the clinical and radiographic outcomes of locking extramedullary plating (LEP) and retrograde intramedullary nailing (RIN) for complete distal femoral intra-articular fractures with metaphyseal comminution.

MATERIALS AND METHODS

Between January 2016 and May 2022, 80 patients (45 men and 35 women; average age, 56.7 years) diagnosed with AO/OTA 33C2 and 33C3 were treated with either LEP or RIN and followed up for at least one year. Post-operative evaluations included radiographic assessments of bone union rate, timing, and alignment. Clinically, the knee joint range of motion (ROM), lower extremity functional scale (LEFS), and Kellgren and Lawrence (KL) grade were analyzed. The complications were also compared.

RESULTS

36 underwent LEP and 44 underwent RIN. Bone union was observed in 69.4% and 63.6% of the patients in the LEP and RIN groups, respectively (p = 0.64). The average union time was 6.9 months for the LEP group and 6.6 months for the RIN group (p = 0.51). A tendency toward varus deformity was observed in the RIN group, although the difference was not statistically significant. No significant differences were observed in knee ROM, LEFS, or KL grade. Complications included non-union (33.8%; RIN, 11; LEP, 16), varus deformity (5%; RIN, 4; LEP, 0), infection (1.3%; RIN, 0; LEP, 1), heterotrophic ossification (1.3%; RIN, 0; LEP, 1), and wound dehiscence (2.5%; RIN, 2; LEP, 0).

CONCLUSIONS

The surgical fixation methods, RIN and LEP, for complete distal femoral intra-articular fractures with metaphyseal comminution showed similar clinical and radiological outcomes. However, regardless of the type of fixation device used, there was a reduced rate of bone union owing to high energy and a less favorable prognosis.

Risk Factors of Failure in 228 Periprosthetic Distal Femur Fractures: A Multicenter Study

OBJECTIVES

To identify risk factors of reoperation to promote union or to address deep surgical-site infection (DSSI) in periprosthetic distal femur fractures treated with lateral distal femoral locking plates (LDFLPs).

METHODS

DESIGN

Multicenter retrospective cohort study.

SETTING

Ten level-I trauma centers.

PATIENT SELECTION CRITERIA

Patients with Orthopaedic Trauma Association/Association of Osteosynthesis (OTA/AO) 33A or 33C periprosthetic distal femur fractures who underwent surgical fixation between January 2012 and December 2019 exclusively using LDFLPs were eligible for inclusion. Patients with pathologic fractures or with follow-up less than 3 months without an outcome event (unplanned reoperation to promote union or for deep surgical infection) before this time point were excluded. Fracture fixation constructs used medial plates, intramedullary nails, or hybrid fixation constructs were excluded from analysis.

OUTCOME MEASURES AND COMPARISONS

To examine the influence of patient demographics, injury characteristics, and features of the fracture fixation construct on the occurrence of unplanned reoperation to promote union or to address a DSSI.

RESULTS

There was an 8.3% rate (19/228) of unplanned reoperation to promote union. Predictive factors for the need for reoperation to promote union included increasing body mass index (odds ratio [OR] = 1.09; 95% confidence interval [CI]: 1.02-1.16; P = 0.01), increasing number of screws in the distal fracture segment (OR = 1.73; 95% CI: 1.06-2.95; P = 0.03), and decreasing proportion of proximal segment screws that are locking (OR = 0.17; 95% CI: 0.03-0.70; P = 0.02) There was a 4.8% rate (11/228) of reoperation to address DSSI. There were no statistically significant predictive factors identified as risk factors of the need for reoperation to address DSSI ( P > 0.05).

CONCLUSIONS

8.3% of periprosthetic distal femur fractures treated at 10 centers with LDFLPs underwent unplanned reoperation to promote union. Increasing patient body mass index and increasing number of screws in the distal fracture segment were found to be predictive factors, whereas increased locking screws in the proximal segment were found to be protective. 4.8% of patients in this cohort underwent reoperation to address DSSI.

LEVEL OF EVIDENCE

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

Severity of Complications after Locking Plate Osteosynthesis in Distal Femur Fractures

Background: Locked plating for distal femur fractures is widely recommended and used. We systematically reviewed clinical studies assessing the benefits and harms of fracture fixation with locked plates in AO/OTA Type 32 and 33 femur fractures. Methods: A comprehensive literature search of PubMed, Embase, Cinahl, Web of Science, and the Cochrane Database was performed. The studies included randomized and non-randomized clinical trials, observational studies, and case series involving patients with distal femur fractures. Studies of other fracture patterns, studies conducted on children, pathological fractures, cadaveric studies, animal models, and those with non-clinical study designs were excluded. Results: 53 studies with 1788 patients were found to satisfy the inclusion and exclusion criteria. The most common harms were nonunion (14.8%), malunion (13%), fixation failure (5.3%), infection (3.7%), and symptomatic implant (3.1%). Time to full weight-bearing ranged from 5 to 24 weeks, averaging 12.3 weeks. The average duration of follow-up was 18.18 months, ranging from 0.5 to 108 months. Surgical time ranged between 40 and 540 min, with an average of 141 min. The length of stay in days was 12.7, ranging from 1 to 61. The average plate length was ten holes, ranging from 5 to 20 holes. Conclusion: This review aimed to systematically synthesize the available evidence on the risk associated with locked plating osteosynthesis in distal femur fractures. Nonunion is the most common harm and is the primary cause of reoperation. The overall combined risk of a major and critical complication (i.e., requiring reoperation) is approximately 20%.

Substantial Loss of Skeletal Muscle Mass Occurs After Femoral Fragility Fracture

BACKGROUND

Femoral fragility fractures in older adults can result in devastating loss of physical function and independence. Skeletal muscle atrophy likely contributes to disability. The purpose of this study was to characterize the change in skeletal muscle mass, investigate the relationship with malnutrition and physical function, and identify risk factors for skeletal muscle loss.

METHODS

Adults ≥65 years of age who were treated with operative fixation of an isolated femoral fragility fracture were enrolled in this multicenter, prospective observational study. Skeletal muscle mass was assessed within 72 hours of admission using multifrequency bioelectrical impedance analysis, which was repeated at 6 weeks, 3 months, and 6 months. Sarcopenia was defined by sex-specific cutoffs for the appendicular skeletal muscle mass index. The Mini Nutritional Assessment was used to measure nutritional status at the time of injury. Physical function was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function domain. Linear mixed models were used to evaluate changes in skeletal muscle mass and PROMIS Physical Function scores over time and to evaluate factors associated with skeletal muscle mass changes.

RESULTS

Ninety participants (74% female) with a mean age of 77.6 ± 9.0 years were enrolled. At the time of injury, 30 (33%) were sarcopenic and 44 (49%) were at risk for malnutrition or had malnutrition. Older age was associated with lower skeletal muscle mass (age of ≥75 versus <75 years: least squares mean [and standard error], -3.3 ± 1.6 kg; p = 0.042). From the time of injury to 6 weeks, participants lost an average of 2.4 kg (9%) of skeletal muscle mass (95% confidence interval [CI] = ‒3.0 to ‒1.8 kg; p < 0.001). This early loss did not recover by 6 months (1.8 kg persistent loss compared with baseline [95% CI = ‒2.5 to ‒1.1 kg]; p < 0.001). Participants with normal nutritional status lost more skeletal muscle mass from baseline to 6 weeks after injury compared with those with malnutrition (1.3 kg more loss [standard error, 0.6 kg]; p = 0.036). A 1-kg decrease in skeletal muscle mass was associated with an 8-point decrease in the PROMIS Physical Function (model parameter estimate, 0.12 [standard error, 0.04]; p = 0.002).

CONCLUSIONS

We found that older adults with femoral fragility fractures lost substantial skeletal muscle mass and physical function. Participants with adequate baseline nutrition actually lost more muscle mass than those who were malnourished, indicating that future investigations of interventions to prevent muscle loss should focus on older adults regardless of nutritional status.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Outcomes of Geriatric Periprosthetic Distal Femur Fractures: Comparison of Fixation Versus Reconstruction

OBJECTIVE

Comparing outcomes of periprosthetic distal femur fractures treated with open reduction and internal fixation (ORIF) versus distal femoral replacement (DFR).

SETTING

Three major academic hospitals within one metropolitan area.

DESIGN

Retrospective.

PATIENTS/PARTICIPANTS

Three hundred seventy patients >64 years old with periprosthetic distal femur fractures were identified and 115 were included (65 ORIF vs. 50 DFR).

INTERVENTION

ORIF with locked plating versus DFR.

MAIN OUTCOME MEASUREMENT

One-year mortality, ambulatory status at 1 year, reoperations, and hospital readmissions.

RESULTS

No differences were observed between ORIF and DFR cohorts regarding demographics or medical history, including Charleston Comorbidity Index. DFR was associated with longer hospital stay (6.09 days ORIF vs. 9.08 days DFR, P < 0.001) and more frequent blood transfusion (12.3% ORIF vs. 44.0% DFR, P < 0.001). Logistic regression analysis using propensity score matching (PSM) demonstrated no statistically significant difference in reoperation, hospital readmission, ambulatory status at 1 year, or 1-year mortality between the 2 cohorts. Finally, applying Bayesian model averaging using PSM to identify risk factors for 1-year mortality demonstrated that increasing age, length of index hospital stay, and 90-day hospital readmission were significantly associated with 1-year mortality, regardless of type of surgical treatment.

CONCLUSION

Rehospitalization, reoperation, ambulatory status, and 1-year mortality are no different between ORIF and DFR in the treatment of geriatric periprosthetic distal femur fractures when PSM is applied to mitigate selection bias. Further study is warranted to elucidate functional outcomes, long-term sequelae, and costs of care related to these treatment options to better guide treatment planning.

LEVEL OF EVIDENCE

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

Subsidence of a Single-Taper Femoral Stem in Primary Total Hip Arthroplasty: Characterization, Associated Factors, and Sequelae

BACKGROUND

We characterized subsidence of an uncemented single-taper femoral stem in primary total hip arthroplasty (THA), determined factors associated with subsidence, and evaluated the impact of subsidence on outcome.

METHODS

This retrospective study included 502 primary THAs performed using a single-taper stem in Dorr type A and B femora between 2014 and 2018. Subsidence was measured based on distance from the greater trochanter to stem shoulder on calibrated X-rays. Demographics, case-specific data, and outcomes were collected. Changes in subsidence and variables associated with subsidence were determined.

RESULTS

Stem subsidence was 1.5 ± 2.3 mm, 1.6 ± 2.0 mm, 2.0 ± 2.6 mm, 2.3 ± 2.3 mm, 2.6 ± 2.5 mm, and 2.7 ± 3.0 mm at 6 weeks, 3 months, 6 months, 1 year, 2 years, and ≥3 years from THA, respectively. Subsidence across all patients at final mean follow-up of 24 months (range, 1 to 101 months) was 2.2 ± 2.6 mm. Pairwise comparison demonstrated that subsidence occurred predominantly within the first 6 months. Significant subsidence (≥5 mm) occurred in 17.3% and was associated with a body mass index (BMI) ≥25 (P=0.04). Dorr type, age, sex, and American Society of Anesthesiologists class were not associated with subsidence. There were two patients (0.4%) who underwent a revision that could be attributed to subsidence. There was no association between subsidence and pain, limp, need for ambulatory aid, or analgesic use.

CONCLUSION

In primary THAs performed using a single-taper prosthesis, average subsidence was 2.2 mm and significant subsidence occurred in 17.3%. Patient BMI was associated with subsidence. Revision surgery related to subsidence was infrequent (0.4%).

Periprosthetic distal femur fractures around total knee replacements: A comprehensive review

With a growing number of patients undergoing total knee replacements globally, coupled with an elderly population, the incidence of periprosthetic fractures around total knee replacements is increasing. As such, this is a highly topical subject that is gaining increasing interest within the orthopaedic community. This review provides a narrative synthesis of the most contemporary literature regarding distal femoral periprosthetic fractures. We review the related epidemiology, initial patient evaluation, the evolution and relevance of the classification systems and treatment options, particularly related to endoprosthetics and hybrid fixation constructs. The latest orthopaedic evidence related to this topic has been included.

Periprosthetic distal femur fractures treated by retrograde intramedullary nails with a 10-degree distal bend achieve significantly better post-operative radiographic alignment when compared to conventional retrograde nails

INTRODUCTION

Periprosthetic distal femur fractures (PPDFFs) are a common complication after total knee arthroplasty (TKA). In the setting of well-fixed TKA components, treatment options include retrograde intramedullary nailing (rIMN) or lateral locked plating. Treatment with rIMN has historically been associated with potential for extension deformity when using conventional nails. We hypothesized that the PPDFFs treated with an intramedullary nail with a specifically designed 10-degree distal bend for periprosthetic fractures would result in improved post-operative sagittal alignment compared to conventional intramedullary nails.

MATERIALS AND METHODS

The study was conducted at a level-1 trauma center over a 12-year period (2010 - 2022). Patients over the age of 18 who sustained a PPDFF treated with rIMN were identified. The primary outcomes of the study were post-operative coronal and sagittal alignment determined by reviewing post-operative radiographs.

RESULTS

A total of 50 patients were included. Twenty-three patients were treated with a rIMN with a 10° distal bend. Twenty-seven patients were treated with a rIMN with distal bend of 5° The mean aPDFA for the 10° distal bend group was 81.7° compared to 92.8° in the 5° distal bend group (p<0.001). There were 3/23 (13%) significant sagittal plane deformities the 10° distal bend group compared to 11/27 (41%) in the 5° distal bend group (p = 0.03). There was one patient with a post-operative extension deformity in the 10° distal bend group compared to 11 patients in the 5° distal bend group (p = 0.02).

CONCLUSION

Retrograde intramedullary nailing of PPDFF with a 10° distal bend results in significantly better alignment in the sagittal plane when compared to a conventional 5° nail. The use of a 5° nail resulted in an extension deformity significantly more frequently. We therefore recommend the utilization of a rIMN with a 10° distal bend when treating PPDFFs.

SUMMARY

Periprosthetic distal femur fractures are a common complication following total knee arthroplasty. While several studies report on the use of retrograde intramedullary nails in the treatment of periprosthetic distal femur fractures, there are limited reports of the use of a novel retrograde intramedullary nail with a 10° distal bend in the treatment of these injuries. Herein we present a radiographic study comparing coronal and sagittal postoperative alignment following treatment with retrograde intramedullary nails with a 10° distal bend versus conventional retrograde nails with a 5° distal bend.

Cost-effectiveness of fixation versus arthroplasty for geriatric distal femur fractures

INTRODUCTION

Geriatric distal femur fractures are challenging to treat. The high mortality rate associated with a loss of mobility in this population has led some authors to compare distal femur fractures to femoral neck fractures with respect to the importance of rapidly regaining mobility in the geriatric population. Acute distal femur replacement has been advocated by some as a preferred treatment over internal fixation because arthroplasty may facilitate a more rapid return to a patient's baseline mobility level. The purpose of this study was to systematically review the literature on the costs and outcomes of fixation and arthroplasty in the geriatric distal femur fracture population and to employ decision modeling techniques to generate evidence-based treatment recommendations.

METHODS

A systematic literature review of clinical studies published since 2000 was conducted to synthesize the available data on outcomes, reoperation rates, and mortality rates after fixation or arthroplasty for distal femur fractures in patients with an average age greater than 70 years. A Markov decision analysis model was created. Costs, health state utilities, reoperation rates, and mortality rates were derived from the systematic literature review and publicly available data. The model was analyzed via probabilistic statistical analysis as well as sensitivity analyses with a willingness-to-pay threshold set at $100,000 per QALY and a 5-year time horizon.

RESULTS

From a US societal perspective, fixation was associated with a greater quality of life benefit (2.44 QALYs vs. 2.34 QALYs) and lower cost ($25,556 vs. $65,536) compared with distal femur replacement for geriatric distal femur fractures. Probabilistic analysis demonstrated that 82 in 100 model outcomes favored fixation over arthroplasty and 18 in 100 model outcomes favored distal femur replacement. Sensitivity analyses demonstrated that this result was robust to small deviations in the cost and functional outcome variables in the model.

CONCLUSION

Compared to distal femur replacement, ORIF is likely to be a more cost-effective treatment for distal femur fractures in the geriatric patient population, though this recommendation is tempered by the relatively low quality of evidence available on the comparative functional outcomes of these treatments.

Distal Femur Replacement Versus Open Reduction and Internal Fixation for Treatment of Periprosthetic Distal Femur Fractures: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare complications and functional outcomes of treatment with primary distal femoral replacement (DFR) versus open reduction and internal fixation (ORIF).

DATA SOURCES

PubMed, Embase, and Cochrane databases were searched for English language studies up to May 19, 2020, identifying 913 studies.

STUDY SELECTION

Studies that assessed complications of periprosthetic distal femur fractures with primary DFR or ORIF were included. Studies with sample size ≤5, mean age <55, nontraumatic indications for DFR, ORIF with nonlocking plates, native distal femoral fractures, or revision surgeries were excluded. Selection adhered to the PRISMA criteria.

DATA EXTRACTION

Study quality was assessed using previously reported criteria. There were 40 Level IV studies, 17 Level III studies, and 1 Level II study.

DATA SYNTHESIS

Fifty-eight studies with 1484 patients were included in the meta-analysis. Complications assessed {incidence rate ratio [IRR] [95% confidence interval (CI)]: 0.78 [0.59-1.03]} and reoperation or revision [IRR (95% CI): 0.71 (0.49-1.04)] were similar between the DFR and ORIF cohorts. The mean knee range of motion was greater in the ORIF cohort (DFR: 90.47 vs. ORIF: 100.36, P < 0.05). The mean Knee Society Score (KSS) (DFR: 79.41 vs. ORIF: 82.07, P = 0.35) and return to preoperative ambulatory status were similar [IRR (95% CI): 0.82 (0.48-1.41)].

CONCLUSIONS

In comparing complications among patients treated for periprosthetic distal femur fracture with DFR or ORIF, there was no difference between the groups. There were also no differences in functional outcomes, although knee range of motion was greater in the ORIF group. This systematic review and meta-analysis highlights the need for future prospective trials evaluating the outcomes of these divergent treatment strategies.

LEVEL OF EVIDENCE

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

Contemporary Distal Femoral Replacements for Supracondylar Femoral Fractures Around Primary and Revision Total Knee Arthroplasties

BACKGROUND

There is a paucity of data on the outcomes of distal femoral replacements (DFRs) in patients with total knee arthroplasty (TKA) periprosthetic fractures. We sought to characterize these patients' survivorship free from rerevision.

METHODS

We retrospectively identified 49 patients, including 34 after primary TKA (primary cohort), 9 after revision TKA, and 6 conversions for failed open reduction and internal fixation (revision cohort) that underwent DFR for a periprosthetic femur fracture. The mean age was 76 years, and 40 patients (82%) were female. The mean follow-up was 4 years. Femoral fixation included 44 cemented stems (90%) and 5 cementless stems (10%). Survivorship free from rerevision was characterized by the Kaplan-Meier method; cox proportional regression was used to analyze the risk factors for rerevision.

RESULTS

Survivorship free from any rerevision at 5 years in the primary and revision cohort was 93% and 18%, respectively. The revision cohort had a 5.3× higher risk of re-revision (P = .008). Survivorship free from re-revision for aseptic loosening at 5 years in the primary and revision cohort was 93% and 53%, respectively. Two of the 3 patients with cementless stems in the primary cohort underwent early rerevision for aseptic loosening, but patients with prior primary TKAs treated with cemented femoral fixation (n = 31) had a 97% 5-year survivorship free from re-revision.

CONCLUSION

Patients with periprosthetic fractures around prior primary TKAs treated with DFRs with cemented femoral fixation had a 97% 5-year survivorship free from any re-revision. DFRs for periprosthetic femur fractures around revision TKAs or conversions of failed open reduction and internal fixations have a 5× increased risk of rerevision.

Review of patient-reported outcomes in periprosthetic distal femur fractures after total knee arthroplasty: a plate or intramedullary nail?

Purpose

This study reviewed the literature regarding the patient-reported treatment outcomes of using either open reduction and internal fixation (ORIF) with a plate and screw system or intramedullary nail (IMN) fixation for periprosthetic distal femur fractures around a total knee arthroplasty.

Methods

A total of 13 studies published in the last 20 years met the inclusion criteria. The studies included 347 patients who were allocated to ORIF (n = 249) and IMN (n = 98) groups according to the implants used. The primary outcome measures were the Knee Society Score or the Western Ontario and McMaster Universities osteoarthritis index. The secondary outcome measures included knee range of motion and the rates of complications, including non-union, malunion, infection, revision total knee arthroplasty, and reoperation. Statistical significance was set at P < 0.05.

Results

The mean Knee Society Scores of ORIF and IMN groups were 83 and 84, respectively; the mean postoperative range of motion of the knee were 99° and 100°, respectively (P < 0.05); the non-union rates were 9.4 and 3.8%, respectively (P > 0.05); the malunion rates were 1.8 and 7.5%, respectively (P < 0.05); surgical site infection rates were 2 and 1.3%, respectively (P > 0.05); the reoperation rates were 9.6 and 5.1%, respectively (P > 0.05); and revision rates of total knee arthroplasty were 2 and 1%, respectively (P > 0.05).

Conclusion

Based on the patient-reported outcome assessments, both ORIF with a plate and screw system and IMN fixation are well-accepted techniques for periprosthetic distal femur fractures around a TKA, and they produce similar functional outcomes.

Biomechanics of periprosthetic femur fractures and early weightbearing

PURPOSE

The incidence of periprosthetic fractures is expected to rise increase by 4.6% every 10 years between 2015 and 2060. There are few large series examining optimal fixation constructs or the influence of early ambulation on outcome. The purpose of this narrative review is to investigate the published biomechanical considerations for periprosthetic fracture fixation, with specific consideration of early postoperative weightbearing.

METHODS

A literature review was performed to identify fracture incidences, etiology, and current trends in weightbearing after fixation. Benefits of early weightbearing, current constructs, and biomechanics are reviewed.

RESULTS

The limited data available support medical benefits and increased union rates with early mobilization. Optimal fixation constructs are not agreed upon, but mechanical studies suggest that dual implant constructs can support physiologic weightbearing loads.

CONCLUSION

Further clinical trials are required to investigate fracture union and hardware complications in dual implant construct.

Periprosthetic femoral re-fractures pathogenesis, classification, and surgical implications

Periprosthetic femoral re-fractures (PFRFs) represent an emerging challenge for orthopaedic surgeons, since their incidence is growing in the last years, but very few experiences about their management have been currently published. The present study aims to (1) introduce, for the first time, an etiologic classification for PRFRs and (2) to provide surgical and pharmacological tips for the correct management of these injuries. Periprosthetic femoral re-fractures (PFRFs) could be classified into traumatic-PFRFs (T-PFRFs) and pathological-PFRFs (P-PFRFs). T-PFRFs, i.e. the "true" periprosthetic re-fractures, present as new fracture lines occurring proximally or distally to a previous periprosthetic fracture, that has correctly healed. They are generally unpredictable injuries but, in selected cases, it is possible to predict them by analyzing the construct used in the treatment of the previous periprosthetic fracture. P-PFRFs, on the other hand, define re-fractures occurring on a previous periprosthetic non-union or delayed union: the new fracture line appears in the same district of the old one. According to the etiologic factors influencing the P-PFRFs pathogenesis, it is possible to define re-fractures caused by mechanical failures, biological failures, septic failures and multifactorial failures, i.e., a combination of the previously mentioned concerns. A successful postoperative outcome, following the surgical management of PFRFs, requires the correct identification of all the underlying causes, which should be promptly and appropriately managed.

The Treatment of Periprosthetic Distal Femoral Fractures After Total Knee Replacement: A Critical Analysis Review

Periprosthetic distal femoral fracture after total knee arthroplasty carries substantial morbidity and mortality regardless of fixation technique. Surgical treatment is favored in most patients compared with conservative therapy because of high rates of nonunion, malunion, and reoperation after casting or bracing. Internal fixation techniques including retrograde intramedullary nailing and locked plating are favored for surgical treatment in most fractures when bone stock in the distal fragment allows for appropriate fixation. In the setting of deficient distal femoral bone stock or femoral component loosening, revision arthroplasty with distal femoral replacement is the favored technique. Further studies with regard to the use of intramedullary nailing, locked plating, and distal femoral replacement are necessary to refine the indications for each technique and to define the use of combinations of these fixation techniques.

Complication Rates after Lateral Plate Fixation of Periprosthetic Distal Femur Fractures: A Multicenter Study

OBJECTIVE

Periprosthetic fractures of the distal femur can be challenging injuries to treat; nonunion rates of up to 22% have been reported. The purpose of this study was to determine the rate of complications and nonunion in a multicenter series, and to identify patient or surgical factors that were associated with nonunion.

DESIGN

Retrospective comparative study SETTING: Three Level 1 trauma centers PATIENTS: Fifty-five patients with a periprosthetic distal femur fracture proximal to a total knee arthroplasty. Minimum follow up for inclusion was six months or until union or failure.

INTERVENTION

Surgical fixation using a precontoured lateral locking plate MAIN OUTCOME MEASUREMENT: Fracture union was the primary outcome. Patient demographic and injury variables (age, comorbidities, fracture classification and characteristics) and surgical technique factors (mode of plate fixation, plate material, working length, screw density, and proximal screw type) were identified and compared between patients who developed a nonunion and those who did not. Regression analysis was performed to identify independent risk factors for nonunion.

RESULTS

The overall rate of nonunion was 18% and the total complication rate was 24%. After additional surgery, 49 of 55 patients went on to heal (89%). There were no statistical differences in patient demographic or injury variables between the union and nonunion groups, and none of the variables studied were independent risk factors for nonunion in the regression analysis.

CONCLUSIONS

In this series of 55 patients with periprosthetic distal femur fractures treated with precontoured lateral locking plates, 18% developed nonunion and the overall complication rate was 24%. No patient or surgical variables were identified as risk factors. Future research should seek to identify patients at high risk for complication and nonunion who could benefit from alternative fixation strategies or distal femoral replacement.

Analysis of the fit of modern pre-contoured distal femur plates: Expect an imperfect contour

The purpose of this study was to determine if the contour of current distal femur plates can reliably be used as a reduction tool and to determine if the presence of a total knee arthroplasty (TKA) influences fit. Thirty-two patients were retrospectively reviewed. Radiographs of 19 patients with normal knees and 21 patients who had undergone TKA were evaluated. Using TraumaCad templating software, the contours of 4 different modern distal femur plates (Depuy Synthes, Stryker, Zimmer Biomet, and Smith & Nephew) were analyzed using a novel measurement technique to evaluate plate fit. To mimic non-locking screws in the shaft, the template was placed on the shaft and the plate to bone (PTB) and condyle to plate (CTP) distances were recorded. The PTB distance measured how closely the plate matched the contour of the metaphyseal flare, while the CTP value represented the distance from the plate to the distal articular surface. Larger PTB and CTP distances represent a higher mismatch between the patient's anatomy and the contour of the plate. There was significant variability in plate fit in all patients. None of the plates fit the patient's anatomy well, with PTB values averaging from 5.5 mm to 9.2 mm. There was no significant difference between normal radiographs and TKA radiographs, suggesting that the presence of a TKA may not contribute to plate fit. The results of this study show that current plate designs may not match the patient's native anatomy prior to fracture. Therefore, caution should be utilized when using non-locking screws in the shaft and using the pre-contoured nature of the plate as a template for reduction. The authors advocate for careful preoperative planning and using contralateral radiographs for templating purposes to prevent malreduction and to assist in device selection for the best device fit per patient.

Biomechanics of Periprosthetic Fixation: Plates, Nails, Cables, and Allografts

Periprosthetic fractures (PPFs) present unique challenges to orthopaedic surgeons in terms of limited cortical fixation options, poor bone quality, cement mantles, and stress risers introduced from the prosthesis. Various fixation strategies have been used in PPFs including the use of intramedullary nails, locked plates, unicortical locking screws, cerclage wires and cables, double-plating techniques, and allograft struts. Here, we will review the biomechanics of various fixation strategies used in PPFs.

Setting Yourself Up for Success: Locked Plating in Periprosthetic Fractures About Total Knee Arthroplasty

As the incidence of total knee arthroplasty increases, a concurrent increase in periprosthetic fractures will also occur. This article focuses on the most common fracture types and current strategies adopted to overcome this challenging clinical problem. Our goal is to outline the role of locking plates in the management of knee periprosthetic fractures.

Comparison of outcomes and analysis of risk factors for non-union in locked plating of closed periprosthetic and non-periprosthetic distal femoral fractures in a retrospective cohort study

BACKGROUND

The primary aim was to compare the outcomes of locked plating of closed distal femur periprosthetic and non-periprosthetic fractures by testing the hypothesis that outcomes would be worse in the periprosthetic group. The secondary aim of this study was to identify risk factors for non-union.

METHODS

A single-center study over an 8-year period utilizing a retrospective cohort design was performed. Sixty-eight patients with periprosthetic fractures and 57 patients with non-periprosthetic fractures met inclusion criteria for the study. There was a significant difference between groups in mean age (80.1 years periprosthetic vs. 70.9 years non-periprosthetic (p < 0.001)). Statistical analysis between groups was used to assess the outcomes of time to union, incidence of non-union, post-operative functionality, incidence of complications, progression to revision surgery, and mortality. A secondary multivariable analysis was used to assess risk factors for non-union and factors positively associated with union.

RESULTS

There were no significant differences in outcomes between groups. Union rates were 83.8% (57/68) in the periprosthetic group and 78.9% (45/57) in the non-periprosthetic group (p = 0.648). Comminution was identified as a significant risk factor for non-union (p = 0.005). Use of a submuscular technique had a significant positive association with union (p = 0.006).

CONCLUSIONS

Outcomes of surgical treatment for periprosthetic and non-periprosthetic distal femur fractures are similar. There is a significant risk of non-union in locked plating of both groups.

Distal Femur Locking Plates Fit Poorly Before and After Total Knee Arthroplasty

OBJECTIVE

To evaluate the fit of distal femur locking plates. Secondarily, we sought to compare plate fit among patients with and without a total knee arthroplasty (TKA).

DESIGN

Retrospective.

SETTING

University hospital.

INTERVENTION

Standard length precontoured distal femur locking plates from 4 manufacturers were digitally templated onto each patient's pre-TKA and post-TKA radiographs.

MAIN OUTCOME MEASUREMENTS

The maximum distance from the plate to the lateral femoral cortex (plate-bone distance) was measured in the metaphyseal region. Mean plate-bone distances were compared between manufacturers and between pre-TKA and post-TKA radiographs.

RESULTS

All implants tested were undercontoured in all patients. Plate-bone distances ranged from 6.6 ± 0.4 mm to 8.0 ± 0.4 mm (mean ± SE) pre-TKA and 8.2 ± 0.3 mm to 8.6 ± 0.3 mm after TKA, indicating worse fit after arthroplasty (P < 0.001). There were also intermanufacturer differences, with Synthes and Smith & Nephew implants demonstrating the lowest plate-bone distances in the pre-TKA and post-TKA groups, respectively. Proportionally, plate-bone increase was greater in the female cohort (16%) compared with the male cohort (8%).

CONCLUSIONS

There was plate-bone mismatch for the distal femur locking plates tested in this study, due to undercontouring of the implants. After patients underwent TKA, poor implant fit was exacerbated. Surgeons must be aware of the potential for deformity if the proximal segment is brought into contact with the implant. These finding may help optimize implant design for the treatment of periprosthetic distal femur fractures.