Outcome of periprosthetic distal femoral fractures following knee arthroplasty

The Effects of Unitizing Nail-Plate Constructs in Distal Femur Fractures: A Biomechanical Study

OBJECTIVES

To assess the biomechanical differences between linked and unlinked constructs in young and osteoporotic cadavers in addition to osteoporotic sawbones.

METHODS

Intraarticular distal femur fractures with comminuted metaphyseal regions were created in three young matched pair cadavers, three osteoporotic matched pair cadavers, and six osteoporotic sawbones. Precontoured distal femur locking plates were placed in addition to a standardized retrograde nail, with unitized constructs having one 4.5 mm locking screw placed distally through the nail. Nonunitized constructs had seven 4.5 mm locking screws placed through the plate around the nail, with one 5 mm distal interlock placed through the nail alone. Cadaveric specimens were subjected to axial fatigue loads between 150 and 1500 N (R Ratio = 10) with 1 Hx frequency for 10,000 cycles. Sawbones were axially loaded at 50% of the ultimate load for fatigue testing to achieve runout, with testing performed with 30 and 300 N (R Ratio = 10) loads with 1 Hz frequency for 10,000 cycles.

RESULTS

In young cadavers, there was no difference in the mean cyclic displacement of the unitized constructs (1.51 ± 0.62mm) compared to the non-unitized constructs (1.34 ± 0.47mm) (Figure 4A), (p = 0.722). In osteoporotic cadavers, there was no difference in the mean cyclic displacement of the unitized constructs (2.46 ± 0.47mm) compared to the non-unitized constructs (2.91 ± 1.49mm) (p =0.639). There was statistically no significant difference in cyclic displacement between the unitized and non-unitized groups in osteoporotic sawbones(p = 0.181).

CONCLUSIONS

Linked constructs did not demonstrate increased axial stiffness or decreased cyclical displacement in comparison to unlinked constructs in young cadaveric specimens, osteoporotic cadaveric specimens, or osteoporotic sawbones.

Outcomes of operatively managed periprosthetic distal femur fractures compared to fractures in patients with native knees

Introduction

With the increasing incidence of total knee arthroplasty (TKA), there is an expected rise in rate of periprosthetic fractures in the coming years. It is unclear how the outcomes of patients with distal femur fractures (DFF) and a total knee arthroplasty compare to patients of the same age group with native knees (NK).

Materials and methods

A retrospective review was completed for distal femur fractures treated with surgical fixation from January 2019-March 2021. We excluded patients <50 years old, non-ambulatory patients, revision surgeries, and patients with less than 90 days of follow-up. A chart review was performed to collect age, gender, BMI, smoking status, American Society of Anesthesiology (ASA) classification, fracture type, fixation method, time to full weight bearing, and complications. Comparisons between the TKA vs native knee groups were performed using t-test, chi-square, and Fisher's exact test where appropriate.

Results

138 patients were included in our study with a mean age of 74 years. 69 DFF ipsilateral to a TKA were included in the study group and 71 DFF were included in the native knee group. Age, sex, BMI, smoking status, and ASA class were similar between the groups. All patients with periprosthetic femur fractures had 33A AO/OTA fracture classification. Patients with native knees were more likely to receive dual implant fixation, 15.5% compared to 4.3% (p = 0.02). Full weight bearing was achieved at 8.5 vs 8.6 weeks between the NK and TKA groups (p = 0.64). The complication rate was 16.9% in the NK group vs. 7.2% in the TKA group (p = 0.21).

Conclusion

Patients with periprosthetic femur fractures have similar time to weight bearing and complications rate with patients with distal femur fracture in native knees. We found a higher utilization rate of dual implant fixation in the native knee group.

Double plating is a suitable option for periprosthetic distal femur fracture compared to single plate fixation and distal femoral arthroplasty

Aims

The purpose of this study was to compare reoperation and revision rates of double plating (DP), single plating using a lateral locking plate (SP), or distal femoral arthroplasty (DFA) for the treatment of periprosthetic distal femur fractures (PDFFs).

Methods

All patients with PDFF primarily treated with DP, SP, or DFA between 2008 and 2022 at a university teaching hospital were included in this retrospective cohort study. The primary outcome was revision surgery for failure following DP, SP, or DFA. Secondary outcome measures included any reoperation, length of hospital stay, and mortality. All basic demographic and relevant implant and injury details were collected. Radiological analysis included fracture classification and evaluation of metaphyseal and medial comminution.

Results

A total of 111 PDFFs (111 patients, median age 82 years (interquartile range (IQR) 75 to 88), 86% female) with 32 (29%) Su classification 1, 37 (34%) Su 2, and 40 (37%) Su 3 fractures were included. The median follow-up was 2.5 years (IQR 1.2 to 5.0). DP, SP, and DFA were used in 15, 66, and 30 patients, respectively. Compared to SP, patients treated with DP were more likely to have metaphyseal comminution (47% vs 14%; p = 0.009), to be low fractures (47% vs 11%; p = 0.009), and to be anatomically reduced (100% vs 71%; p = 0.030). Patients selected for DFA displayed comparable amounts of medial/metaphyseal comminution as those who underwent DP. At a minimum follow-up of two years, revision surgery for failure was performed in 11 (9.9%) cases at a median of five months (IQR 2 to 9): 0 DP patients (0%), 9 SP (14%), and 2 DFA (6.7%) (p = 0.249).

Conclusion

Using a strategy of DP fixation in fractures, where the fracture was low but there was enough distal bone to accommodate locking screws, and where there is metaphyseal comminution, resulted in equivalent survival free from revision or reoperation compared to DFA and SP fixation.

Retrograde intramedullary nail fixation with oblique fixed angle screws versus locking plates in periprosthetic supracondylar fractures after total knee arthroplasty

PURPOSE

Common surgical procedures in the treatment of periprosthetic distal femur fractures (PPFF) include osteosynthesis with fixed angle locking plates (LP) and retrograde intramedullary nails (RIN). This study aimed to compare LPs to RINs with oblique fixed angle screws in terms of complications, radiographic results and functional outcome.

METHODS

63 PPFF in 59 patients who underwent treatment in between 2009 and 2020 were included and retrospectively reviewed. The anatomic lateral and posterior distal femoral angle (aLDFA and aPDFA) were measured on post-surgery radiographs. The Fracture Mobility Score (FMS) pre- and post-surgery, information about perceived instability in the operated leg and the level of pain were obtained via a questionnaire and previous follow-up (FU) examinations in 30 patients (32 fractures).

RESULTS

The collective (median age: 78 years) included 22 fractures treated with a RIN and 41 fractures fixed with a LP. There was no difference in the occurrence of complications (median FU: 21.5 months) however the rate of implant failures requiring an implant replacement was higher in fractures treated with a LP (p = 0.043). The aPDFA was greater in fractures treated with a RIN (p = 0.04). The functional outcome was comparable between both groups (median FU: 24.5 months) with a lower outcome in the post-surgery FMS (p =  < 0.001).

CONCLUSION

Fractures treated with RIN resulted in an increased recurvation of the femur however the rate of complications and the functional outcome were comparable between the groups. The need for implant replacements following complications was higher in the LP group.

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.

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.

Far cortical locking constructs for fixation of distal femur fractures in an Asian population: A prospective observational study

BACKGROUND

The stiffness of locked plates suppresses healing process, prompting the introduction of far cortical locking to address this issue. This study aimed to demonstrate the clinical efficacy of far cortical locking constructs in treating distal femoral fractures in an Asian population.

METHODS

This multicenter prospective observational study was conducted at four university hospitals between February 2018 and February 2021. Demographic data, the presence of metaphyseal comminution, and surgical fixation details were recorded. Clinical outcomes, including single-leg standing, EQ-5D, and EQ-VAS scores, and radiologic outcomes, including the RUST score of each cortex, were evaluated and compared according to the presence of metaphyseal comminution.

RESULTS

There were 37 patients (14 men and 23 women) with a mean age of 67.3 ± 11.8 years. Twenty-two patients had metaphyseal comminution (59%), and 15 presented simple fractures in metaphyseal areas. Four patients (13%) could stand on one leg >10s at 6 weeks, and 24 patients (92%) at 1 year. EQ-5D increased from 0.022 ± 0.388 to 0.692 ± 0.347, and the mean EQ-VAS 51.1 ± 13.1 to 74.1 ± 24.1 between discharge (n = 37) and post-operative 1 year (n = 33), respectively. RUST score presented increment for time, from 6.2 ± 1.8 at 6 week to 11.6 ± 1.1 at 1 year. Radiological healing demonstrated rapid increase from week 6 (16/28, 43%) to month 3 (27/31, 87%), with no obvious increase was observed in 6 months (23/26, 89%) or 12 months (25/28, 89%). Simple metaphyseal fractures presented significantly higher RUST scores at 6 weeks and 3 months, but there was no difference in RUST scores at 6 months or 1 year according to metaphyseal comminution.

CONCLUSIONS

Plate constructs with far cortical locking screws provided safe and effective fixation for distal femoral fractures, with consistent radiological and clinical results, regardless of metaphyseal comminution.

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%.

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.

Retrograde Intramedullary Nailing Versus Locked Plating for Extreme Distal Periprosthetic Femur Fractures: A Multicenter Retrospective Cohort Study

OBJECTIVES

To compare clinical and radiographic outcomes after retrograde intramedullary nailing (rIMN) versus locked plating (LP) of "extreme distal" periprosthetic femur fractures, defined as those that contact or extend distal to the anterior flange.

METHODS

DESIGN

Retrospective review.

SETTING

Eight academic level I trauma centers.

PATIENT SELECTION CRITERIA

Adult patients with periprosthetic distal femur fractures at or distal to the anterior flange (OTA/AO 33B-C[VB1]) treated with rIMN or LP.

OUTCOME MEASURES AND COMPARISONS

The primary outcome was reoperation to promote healing or to treat infection (reoperation for elective removal of symptomatic hardware was excluded from this analysis). Secondary outcomes included nonunion, delayed union, fixation failure, infection, overall reoperation rate, distal femoral alignment, and ambulatory status at final follow-up. Outcomes were compared between patients treated with rIMN or LP.

RESULTS

Seventy-one patients treated with rIMN and 224 patients treated with LP were included. The rIMN group had fewer points of fixation in the distal segment (rIMN: 3.5 ± 1.1 vs. LP: 6.0 ± 1.1, P < 0.001) and more patients who were allowed to weight-bear as tolerated immediately postoperatively (rIMN: 45%; LP: 9%, P < 0.01). Reoperation to promote union and/or treat infection was 8% in the rIMN group and 16% in the LP group ( P = 0.122). There were no significant differences in nonunion ( P > 0.999), delayed union ( P = 0.079), fixation failure ( P > 0.999), infection ( P = 0.084), or overall reoperation rate ( P > 0.999). Significantly more patients in the rIMN group were ambulatory without assistive devices at final follow-up (rIMN: 35%, LP: 18%, P = 0.008).

CONCLUSIONS

rIMN of extreme distal periprosthetic femur fractures has similar complication rates compared with LP, with a possible advantage of earlier return to weight-bearing. Surgeons can consider this treatment strategy in all fractures with stable implants and amenable prosthesis geometry, even extreme distal fractures.

LEVEL OF EVIDENCE

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

Dual Plate Fixation of Periprosthetic Distal Femur Fractures

OBJECTIVES

Dual implants for distal femur periprosthetic fractures is a growing area of interest for these challenging fractures with dual plating (DP) emerging as a viable construct for these injuries. In the current study, an experience with DP constructs is described.

METHODS

DESIGN

Retrospective case series with comparison group.

SETTING

Level 1 academic trauma center.

PATIENT SELECTION CRITERIA

Adults >50 years old sustaining comminuted OTA/AO 33-A2 or 33-A3 DFPF treated with either DP or a single distal femur locking plating (DFLP). Patients with simple 33-A1 fractures were excluded. Prior to 2018, patients underwent DFLP after which the treatment of choice became DP.

OUTCOME MEASURES AND COMPARISONS

Reoperation rate, alignment, and complications.

RESULTS

34 patients treated with DFLP and 38 with DP met inclusion and follow up criteria. Average follow up was 18.2 ± 13.8 months in the DFLP group and 19.8 ± 16.1 months in the DP group ( P = 0.339). The average patient age in the DFLP group was 74.8 ± 7.3 years compared to 75.9 ± 11.3 years in the DP group. There were no statistical differences in demographics, fracture morphology, loss of reduction, or reoperation for any cause ( P >.05). DP patients were more likely to be weight bearing in the twelve-week postoperative period ( P <0.001) and return to their baseline ambulatory status ( P = 0.004) compared to DFLP patients.

CONCLUSIONS

Dual plating of distal femoral periprosthetic fractures maintained coronal alignment with a low reoperation rate even with immediate weight bearing and these patients regained baseline level of ambulation more reliably as compared to patients treated with a single distal femoral locking plate.

LEVEL OF EVIDENCE

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

Robotic-assisted total knee arthroplasty results in decreased incidence of anterior femoral notching compared to posterior referenced instrumented total knee arthroplasty

OBJECTIVE

Periprosthetic fracture (PPF) is an uncommon but devastating complication after total knee arthroplasty (TKA). Anterior femoral notching (AFN) is one of a perioperative risk factor for PPF. The main purpose of this study was to compare between the rates of anterior femoral notching (AFN) and supracondylar periprosthetic femoral fracture (sPPF) of manual TKA and robotic arm-assisted TKA (RATKA). Meanwhile, blood loss, transfusion rates, inflammatory responses, complications, early clinical and radiological outcomes were also assessed.

METHODS

This retrospective study included 330 patients (133 RATKA and 197 manual TKA). Differences in risks of inflammatory, blood loss, complications (periprosthetic fracture and periprosthetic joint infection), pre-operative and post-operative distal lateral femoral angle (LDFA), distal femoral width (DFW), prosthesis-distal femoral width (PDFW) ratio, AFN, femoral component flexion angle (FCFA), peri-operative and post-operative functional outcomes between the RATKA and manual TKA groups were compared.

RESULTS

The operation time and postoperative CRP level in the RATKA group was significantly longer and higher than that in the manual TKA group (p < .001). However, there was no significant difference in postoperative WBC level (p = .217), hemoglobin loss (p = .362), postoperative drainage (p = .836), and periprosthetic fracture (p = 1.000). There was no significant difference in LDFA (p > .05), DFW(p = .834), PDFW ratio (p = .089) and FCFA (p = .315) between the two groups, but the rate of AFN in the RATKA group was significantly lower than that in the manual TKA group (p < .05). There was no significant difference in ROM between the two groups on POD3, POD 90 and 1 year (p < .05), but the FJS-12 score in the RATKA group was higher than that in the manual TKA group on 1 year (p = .001).

CONCLUSION

Robotic-assisted total knee arthroplasty can decrease the incidence of anterior femoral notching compared to posterior referenced instrumented total knee arthroplasty.

Does Far Cortical Locking Improve Fracture Healing in Distal Femur Fractures: A Randomised, Controlled, Prospective Multicentre Study

(1) Background: Bone healing is influenced by various mechanical factors, such as stability, interfragmentary motion, strain rate, and direction of loading. Far cortical locking (FCL) is a novel screw design that promotes bone healing through controlled fracture motion. (2) Methods: This study compared the outcome of distal femur fractures treated with FCL or SL (standard locking) screws and an NCB plate in a randomised controlled prospective multicentre trial. The radiographic union scale (RUST) and healing time was used to quantify bone healing on follow-up imaging. (3) Results: The study included 21 patients with distal femur fractures, 7 treated with SL and 14 treated with FCL screws. The mean working length for patients with SL screws was 6.1, whereas for FCL screws, it was 3.9. The mean RUST score at 6 months post fracture was 8.0 for patients with SL plates and 7.3 for patients with FCL plates (p value > 0.05). The mean healing time was 6.5 months for patients with SL plates and 9.9 months for patients with FCL plates (p value < 0.05). (4) Conclusions: Fractures fixed with SL plates had longer working lengths and faster healing times when compared to FCL constructs, suggesting that an adequate working length is important for fracture healing regardless of screw choice.

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.

Periprosthetic distal femoral fractures after total knee replacement treated by ORIF. Mid to long-term follow-up study in 12 patients

Periprosthetic fractures following total knee arthroplasty are a quite uncommon traumatic lesion that often are present in elderly patients with osteoporosis and comorbidities. The most common periprosthetic fracture affects the distal femur. The main internal fixation techniques are ORIF with a locking plate and retrograde intramedullary nailing. In the present study, we report the medium-long term results in 12 patients with a distal femoral periprosthetic fracture stabilized with a locking plate. We reviewed 12 patients affected by a periprosthetic distal femur fracture surgically treated between 2010 and 2016 by ORIF using a locking compression plate after an average follow-up of 5.75 years. The average age of the patients at diagnosis was 78 years. The mean interval time between knee arthroplasty and distal femoral fracture was 8.25 years. Clinical results were assessed using the WOMAC score, while radiographic results according to Beals and Tower's criteria. All fractures of our series were type II according to the Rorabeck and Taylor classification. At follow-up, the WOMAC score ranged from 40.5 to 76.5 points (average 53.92). Radiographic results, according to Beals and Tower's criteria, were excellent in 5 patients and good in 7. All patients returned to their previous daily activities. We believe that reduction and internal fixation with a locking plate is a surgical option of treatment that provides satisfactory clinical and radiological results in Rorabeck type II periprosthetic distal femoral fractures.

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.

Risk Factors for Reoperation to Promote Union in 1111 Distal Femur Fractures

OBJECTIVES

To identify modifiable and nonmodifiable risk factors for reoperation to promote union after distal femur fracture.

DESIGN

Multicenter retrospective cohort study.

SETTING

Ten Level-I trauma centers.

PATIENTS/PARTICIPANTS

Patients with OTA/AO 33A or C distal femur fractures (n = 1111).

INTERVENTION

Surgical fixation of distal femur fracture. Fixation constructs were classified as lateral plate, dual plate, nail, or nail plate combination.

MAIN OUTCOME MEASUREMENTS

The outcome of interest was unplanned reoperation to promote union.

RESULTS

There was an 11% (121/1111) rate of unplanned reoperation to promote union. In the multivariate analysis, predictive factors included body mass index [odds ratio (OR) = 1.18; 95% confidence interval (CI), 1.06-1.32; P < 0.01], intra-articular fracture (OR = 1.57; 95% CI, 1.01-2.45; P = 0.04), type III open injury (OR = 2.29; 95% CI, 1.41-3.72; P < 0.01), the presence of medial comminution (OR = 1.85; 95% CI, 1.14-3.06; P = 0.01), and medial translation on postoperative radiographs (OR = 1.23 per one 10th of condylar width; 95% CI, 1.01-1.48; P = 0.03). Construct type was not significantly predictive.

CONCLUSIONS

Eleven percent of distal femur fractures underwent unplanned reoperation to promote union. Body mass index, intra-articular fracture, type III open injury, medial comminution, and medial translation on postoperative radiographs were predictive factors. Construct type was not associated with unplanned reoperation; however, this conclusion was limited by small numbers in the dual plate and nail plate groups.

LEVEL OF EVIDENCE

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

Technical Trick: Supplemental Medial Column Screw Fixation of Distal Femur Fractures Treated With a Laterally Based Locked Plate

SUMMARY

Given known failure rates after lateral plating of distal femur fractures, there is an increasing interest in augmenting fixation to improve outcomes. The addition of medial plates or intramedullary nails have been described with promising results, decreasing nonunion and varus collapse rates. However, the use of dual implants increases implant costs, adds surgical complexity, and requires a second surgical approach that may increase morbidity. A supplemental, percutaneously placed, medial column screw may provide a less invasive means of improving stability and achieving fracture union compared with lateral plating alone.

Distal Femoral Replacement versus Operative Fixation for Periprosthetic Distal Femur Fractures: A Systematic Review and Meta-Analysis

BACKGROUND

Open reduction and internal fixation (ORIF) and distal femoral replacement (DFR) have been utilized in the management of periprosthetic distal femur fractures. At present, much of the literature has been limited to small retrospective series. The purpose of the current investigation was to present the results of pooled data to determine the complication rates associated with ORIF and DFR.

METHODS

Publications from 2010 to 2020 describing 10 or more periprosthetic distal femur fractures treated with ORIF (ie, single plate, intramedullary nail, and dual fixation) or DFR were included, resulting in 32 publications and 1,258 fractures (977 ORIF and 281 DFR). Occurrence of surgical complications, reoperations, and medical complications were evaluated and compared.

RESULTS

The rate of surgical complications (ORIF versus DFR, 20.5 versus 14.9%, P = 1.0) and reoperations (12.9 versus 12.5%, P = 1.0) following DFR were similar. However, pooled analyses demonstrated that patients treated with DFR had a higher medical complication rate (ORIF versus DFR, 8.5 versus 23.1%, P = .0006).

CONCLUSION

ORIF and DFR for the treatment of periprosthetic distal femur fractures have similar surgical complication and reoperation profiles. While this review found an increased rate of medical complication following DFR, there are limitations in quality reporting in the literature, which should be considered when interpreting the study's findings. Failed ORIF can be salvaged with DFR, but the difficulty of this reoperation is dependent on the ORIF technique that was used. With future prospective studies, this review can help guide management of these fractures.

[Techniques and results of primary hip arthroplasty in geriatric acetabular fractures]

As a result of demographic changes, there is an increase in geriatric acetabular fractures [1, 2]. Geriatric patients often have comorbidities, such as pre-existing coxarthritis, reduced bone quality or limited compliance, which makes injury-adapted follow-up treatment difficult [3]. As a result joint-preserving interventions often fail at an early stage, so that hip arthroplasty is necessary in the short term. The 1‑year mortality after surgically stabilized acetabular fractures is 8.1%, a significant increase by a factor of 4 compared to the age group [4]. This illustrates that differentiated criteria for the indication of joint-preserving surgery versus arthroplasty are necessary to avoid reoperations and complications. Criteria for the indications for primary arthroplasty are fracture type, pre-existing coxarthritis, poor bone quality, limited compliance and patient age (> 75 years) [5, 6].In the following article, three treatment strategies for geriatric acetabular fractures and periprosthetic acetabular fractures are presented; the 1‑stage prosthesis implantation without osteosynthesis, the 1‑stage prosthesis implantation with osteosynthesis and the 2‑stage approach with limited osteosynthesis and early total arthroplasty. The advantages and disadvantages of these options are presented based on cases and the various aspects of the treatment. The treatment of geriatric acetabular fractures is an operative challenge for the surgeon and requires a high level of expertise in both special trauma surgery and revision arthroplasty and thus represents a special interface in the fields of orthopedics and trauma surgery.

Surgical outcomes of periprosthetic distal femur fractures after total knee arthroplasty classified by Su et al. system

Background

Periprosthetic fractures of the distal femur remain a challenge to treat due to variations in both patient- and fracture-specific factors. This study was designed to analyze the outcomes of different subtypes of periprosthetic distal femur fractures based on the Su et al. classification system.

Methods

Thirty-six patients were classified with Su et al. system. All Type I and II fractures were managed with a locking plate. Most Type III fractures were managed with locking plate, while two were managed with long-stem revision arthroplasty due to evidence of implant loosening. Outcomes were measured and analyzed based on healing time, revision rate, and complication rate.

Results

Of the 36 patients, 30 (83.3%) achieved acceptable fracture union, while the remaining 6 (16.7%) experienced either delayed union or non-union. Type I fractures showed a significantly lower healing time than Type II and III fractures managed by locking plate. Delayed union was present in the Type II group, while non-union was recorded for two Type III fractures. Need for revision was more prevalent in fracture Types II and III.

Conclusion

The Su et al. system of classification for periprosthetic fractures of the distal femur matches the clinical outcomes of this study and would seem to be useful in the approach to the treatment of these fractures. The majority of these fractures can be managed with locking plate with reasonable results. However, if the implant is loosened in Type III fractures, revision arthroplasty is suggested.

Nonsurgical management of atraumatic early distal femoral periprosthetic insufficiency fracture after primary total knee arthroplasty, a report of two cases

Periprosthetic distal femoral fractures after primary total knee arthroplasty (TKA) are considered rare; however, they pose a challenge for the treating surgeon, and the management options are mostly surgical (open reduction and internal fixation or revision surgery). We present two female patients who developed atraumatic lateral femoral condyle fractures three weeks after primary TKA; both were treated nonsurgically with acceptable outcomes and patient satisfaction. We believe that nonsurgical management of periprosthetic distal femoral fractures could be an economical solution in selected cases; it also could help maintain the distal femoral bone stock till a revision surgery is performed.

Interprosthetic Femur Fractures: A Review Article

➢

The prevalence of interprosthetic femur fractures (IFFs) is rising with the aging population and increased prevalence of total joint arthroplasty.

➢

IFFs have high rates of complications and high associated morbidity and mortality.

➢

The main treatment methods available for IFFs include plate fixation, intramedullary nailing, combined plate fixation and intramedullary nailing, and revision arthroplasty including partial and total femur replacement.

➢

There have been several proposed classification systems and at least 1 proposed treatment algorithm for IFFs; however, there is no consensus.

➢

Whichever treatment option is chosen, goals of surgery should include preservation of blood supply, restoration of length, alignment, rotation, and sufficient stabilization to allow for early mobilization.

Results of Low Distal Femur Periprosthetic Fractures

OBJECTIVES

To compare retrograde intramedullary nail (RIMN) and open reduction internal fixation (ORIF) in very distal periprosthetic distal femur fractures (PDFFs) to determine whether RIMN is an acceptable option for these fractures that are often considered too distal for IMN due to limited bone stock.

DESIGN

Retrospective comparative series.

SETTING

Level 1 trauma center.

PATIENTS

Patients were treated with fracture fixation for a very distal PDFF, defined as the fracture extending to the anterior flange of the implant or distal. Fifty-six patients met inclusion criteria, with 8 excluded for less than 12 months of follow-up.

INTERVENTION

The intervention involved fracture fixation with RIMN or ORIF.

MAIN OUTCOME MEASUREMENTS

The primary outcome was unplanned return to surgery. Secondary outcomes included fracture union, radiographic alignment, visual analog score, and Patient-Reported Outcome Measurement Information System (PROMIS) Physical Function (PF) and Pain Interference.

RESULTS

The mean follow-up period was 27 months. Twelve patients were treated with ORIF and 36 with RIMN. Twenty-one fractures were at the flange, and 27 extended distal to the flange. There were no differences between fixation methods for reoperation, deep infection, nonunion, malunion, visual analog score pain score, and PROMIS Pain Interference score. The mean PROMIS PF score was higher in the RIMN group compared with that in the ORIF group. There were 5 reoperations in the RIMN group (14%) and 3 in the ORIF group (25%).

CONCLUSIONS

This is the largest series, to the best of our knowledge, of a subset of very distal PDFFs. The results suggest that RIMN may be an acceptable treatment option for these very difficult fractures.

LEVEL OF EVIDENCE

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

Practical approach to the native distal femur fractures in the elderly: A rapid review over the recent trends

Significant work has been done in recent years on treatment strategies for distal femur fractures. Inclusive reviews on periprosthetic fractures of distal femur have been carried out recently, but there is a lack of such reviews on the subject of native distal femur fractures in the recent literature. In this narrative review, we are set out to address the latest updates on geriatric non-periprosthetic distal femur fractures, and perform a rapid review over different treatment options, arriving at a summarized proposed treatment algorithm.

Comminuted periprosthetic distal femoral fractures have greater postoperative extension malalignment

INTRODUCTION

Comminution is a significant aspect of periprosthetic distal femoral fracture characterization and may influence post-surgical outcomes. Existing classification systems that guide treatment decisions do not take into account comminution and current literature is unclear on which surgical approach is optimal. We hypothesize that fractures with comminution will have poorer quality post-reduction alignment, especially with a lateral approach.

MATERIALS AND METHODS

37 study patients were identified with billing codes designating a distal femoral periprosthetic fracture. A retrospective chart review was performed to categorize fractures by absence or presence of comminution and medial parapatellar versus lateral surgical approach. These patients underwent an imaging evaluation for the primary outcome of reduction quality including the anatomic lateral distal femoral angle (LDFA) and the posterior distal femoral angle (PDFA). Differences in radiographic outcomes were analyzed with Wilcoxon/Kruskal-Wallis tests, and analysis by approach was through Fisher's exact test.

RESULTS

Patients with comminuted fractures had significantly greater extension of the fragment (PDFA = 95.4° vs 90.0°, p = 0.018) and similar coronal alignment (LDFA = 85.3° vs 86.3°, p = 0.83) of the knee compared to non-comminuted fractures after surgical reduction. This difference was more prominent amongst those treated with a lateral approach (PDFA = 96.1° vs 89.4°, p = 0.032) than with a medial approach (PDFA = 93.7° vs 91.5°, p = 0.41) (Table 1).

DISCUSSION

Current classification systems and treatment guidelines for periprosthetic distal femoral fractures do not adequately address several issues that may influence treatment outcomes, especially comminution. Comminuted fractures had greater post-reduction extension malalignment, falling outside the recommended PDFA range of 87-90°, especially with a lateral approach. Consideration should be given to surgical approach and techniques to reduce excessive extension when treating comminuted periprosthetic distal femoral fractures.

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.

Management, outcome, and novel classification system of periprosthetic fractures in patients with transcutaneous osseointegrated prosthetic systems (TOPS)-a retrospective cohort analysis

INTRODUCTION

Transcutaneous osseointegrated prosthetic systems (TOPS) are anchored prosthetic systems for major limb loss. Sometimes TOPS patients suffer from periprosthetic fractures. The aim of this study was to analyze the management and outcomes of periprosthetic fractures in patients with TOPS and to introduce a novel classification system for this entity.

MATERIAL/METHODS

Since 2010, 140 patients were treated with TOPS after transfemoral amputation in two centers in Germany. Fifteen patients sustained periprosthetic fractures, with five intra- and ten postoperative fractures. The outcome was analyzed by Prosthesis Mobility Questionnaire (PMQ), K-level and prosthesis wear time per day. A subgroup analysis for the body mass index (BMI) was performed.

RESULTS

All postoperative fractures were treated with implant-retaining osteosynthesis. Fourteen fractures healed without complications after a mean of 3 months. One postoperative fracture developed a clinically asymptomatic firm non-union. No Endo-Fixstem had to be removed. For the fracture and control group, a significant increase of the PMQ (p < 0.001) and K-level (p < 0.001) was observed after TOPS treatment compared to the preoperative baseline. Furthermore, the subgroup analysis showed a significant increase of the PMQ and K-level for both normal weight (p = 0.002) and overweight patients (p < 0.001). Of interest, overweight patients even showed a significantly higher increase in scores compared to normal weight patients, regardless of periprosthetic fracture.

CONCLUSION

Periprosthetic fractures do not necessarily worsen outcomes of TOPS treatment. Proper classification and standardized appropriate treatment strategies according to fracture morphology are paramount for reliably good outcomes. We recommend to not remove or exchange the implant (Endo-Fixstem) even if it is assembly. Higher BMI did not have an impact onto rehabilitation success after TOPS to major limb loss of the lower extremity.

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.

Surgical Tips and Tricks for Distal Femur Plating

Distal femur fractures are challenging fractures to treat, with nonunion rates as high as 22%. Precontoured locking plates have mitigated some earlier causes of failure, while introducing new challenges. The recognition of troublesome injury patterns and appropriate preoperative planning can avoid common pitfalls. Adjunctive techniques, including the use of a radiolucent triangle, an external fixator, unicortical plates, and crossing K-wires, can assist with fracture reduction and maintenance. It is important to understand the common pitfalls involved with distal femur plating and to consider a wide array of techniques to combat these challenges.

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.

Interprosthetic Femoral Fractures Surgical Treatment in Geriatric Patients

Background

Total hip (THA) and total knee arthroplasty (TKA) are becoming an increasingly standard procedure in the whole world. In conjunction with an aging population and increased prevalence of osteoporosis, proper management of periprosthetic, and interprosthetic fractures is of great interest to orthopedic surgeons. This study aims to report the clinical and radiographic outcomes, complications and reoperations of IFFs in geriatric patients.

Methods

A retrospective single-institution case series study was conducted. Between 2011 and 2019, 83 patients underwent surgical treatment for periprosthetic femoral fractures. Thirteen fractures were identified as IFFs. Patient demographics and comorbidities were collected preoperatively, and fractures were classified with the Vancouver and AO unified classification system (AO-UCS).

Results

We included 12 patients (13 hips) with IFFs (AO-UCS type IV.3 B (2/13) type IV.3 C (3/13), type IV.3 D (8/13)). The average patient age was 86.54 (range, 79-89) years. There were 10 females and 2 males. Perioperative morbidity has been identified in 10 of the 12 patients, and the 3-month and 1-year mortality were reported in 2 and 3 patients, respectively. Cerclage cables were used in 9 of 12 patients. One of 12 patients showed a local complication, with no documented implant failure or revision. Patients achieved complete union and returned to their preoperative ambulatory status, and full weight-bearing at an average of 5 (range, 2 to 7) months later.

Conclusion

Management of IFF can be challenging because these fractures require extensive surgical expertise. Locking plate seems to be a valuable treatment option for geriatric patients with IFFs. Despite the complexity of this type of fracture, the overall complication and revision rate, as well as the radiographic outcome are good to excellent.

Level of Evidence

Level III, Therapeutic study.

Anterior femoral notching ≥ 3 mm is associated with increased risk for supracondylar periprosthetic femoral fracture after total knee arthroplasty: a systematic review and meta-analysis

PURPOSE

Anterior femoral notching (AFN) may be associated with a higher risk for supracondylar periprosthetic fracture (sPPF) after total knee arthroplasty (TKA), although studies have yielded inconclusive results. We aimed to systematically investigate and meta-analyze the best available evidence regarding the association between AFN and the risk of sPPF after TKA.

METHODS

A comprehensive search of PubMed, Scopus, Mendeley, Google Scholar and Cochrane databases was performed, from conception to February 29, 2020. Data were expressed as odds ratio (OR) with 95% confidence intervals (CI). I²-index was employed for heterogeneity. Newcastle-Ottawa scale was implemented for quality assessment of the included studies.

RESULTS

Nine studies fulfilled the eligibility criteria, including a total of 3264 patients subjected to TKA. Among them, there were 150 patients who sustained a sPPF. Overall, patients exposed to AFN (AFN group) demonstrated an increased risk for sPPF compared to those not exposed (control group) (OR 3.91, 95% CI 1.22-12.58, p = 0.02; I² 68.52%). Subgroup analysis based on AFN depth with a cut-off value of 3 mm further clarified this association. Patients with AFN ≥ 3mm were at higher risk for sPPF compared to patients with AFN < 3 mm and control group (OR 4.85, 95% CI 2.08-11.33, p = 0.00; I² 0.0%). On the contrary, fracture risk was not significant for patients with AFN < 3 mm compared to the control group (OR 5.0, 95% CI 0.44-56.82, p = 0.19; I² 42.99%).

CONCLUSION

Patients, exposed to AFN ≥ 3 mm in depth, are at higher risk for sustaining a sPPF.

Comparison of different fixation techniques for periprosthetic fractures: a biomechanical study of a new implant

INTRODUCTION

The ideal treatment method for periprosthetic fractures is controversial due to the risks of current methods. Single-cortex screw fixation in prosthesis may lead to implant failure. Therefore, we aimed to develop an implant that lowers the risk for complications. For this study, we designed and tested two new implant models. The first model was a plate with a combination of U nails and cerclage holes. The second model was a U nail plate with a screw, which combines a plate screw with U nail (staples). Our study aimed to compare the stability of two newly designed implants with classical treatment modalities. We used 27 (in 3 groups) artificial bone models and 9 different test models.

METHODS

The ISO 7206-4:2010 (E) standards were used for 27 bones in nine groups tested under laboratory conditions. In our study, we examined nine different groups. In group 1, hip the prosthesis was extracted, and a revision femoral stem was embedded. In group 2, periprosthetic fractures were repaired with a plate and cable. In group 3, periprosthetic fractures were repaired with a plate and stapler. In group 4, periprosthetic fractures were repaired with a plate and stapler cable. In group 5, periprosthetic fractures were repaired with a plate stapler and screw. Groups 6 and 7 were the control groups. Group 6 was the only artificial bone group, and group 7 was the prosthesis embedded bone group. Group 8 was periprosthetic fractures treated with unicortical screw fixation with cerclage, and group 9 was periprosthetic fractures treated with unicortical screw fixation. Axial loading was applied to the bones. The yield strength of the system was determined by loading the synthetic bone models with a constant compression speed of 5 mm/min through the centre of motion using the Geratech SH 2000 testing system. During the tests, load and displacement values were recorded, and the stiffness of the models was calculated based on those values.

RESULTS

According to our results, the greatest durability was found in the revision hip prosthesis group (1511 N), and the weakest performance was found in the plate with the stapler implant group (163N). When comparing the data of groups according to compression, significant differences were found in group 2 with groups 1, 4, 5, and 7; group 3 with group 1; group 8 with groups 1 and 5; and group 9 with 1, 5, 7, and according to breakage, significant differences were found in group2 with groups 1, 3, 5, and 7; group 3 with group 1; group 8 with groups 1 and 5; and group 9 with groups 1, 5, and 7 (p<0.001).

DISCUSSION

The revision hip prosthesis treatment for periprosthetic fractures showed the best performance, followed by the plate with stapler screw. In older patients, U nail-augmented implants may be a good alternative for periprosthetic fractures. Unicortical screw and cerclage wire combination fixation results were unsatisfactory results in this study.

CONCLUSION

This is an experimental study, so further studies, especially patient-specific studies, should be made to expand the findings of this study.

Technical Trick: Dual Plate Fixation of Periprosthetic Distal Femur Fractures

Treatment of periprosthetic distal femur fractures remains challenging due to assuring adequate distal fixation. Traditional treatment options include lateral locked plating and retrograde nailing, although recently dual implant constructs have been explored with promising results. Allowing immediate weight-bearing in this patient population has benefits with regards to rehabilitation and outcome. Recent literature has focused on nail-plate constructs, however plate-plate constructs are preferred at our institution as they do not require arthroplasty component compatibility, facilitate the coronal plane reduction, and allow for immediate weight-bearing.

Excellent outcomes after double-locked plating in very low periprosthetic distal femoral fractures

INTRODUCTION

Very low periprosthetic distal femur fractures (PPDFFs) are rare injuries and often have a relatively high failure rate after single lateral locked plating. The double plating technique yields good outcomes in osteoporotic fractures of the distal femur. To date, there is limited information on double-locked plate fixation of very low PPDFFs. This study aimed to evaluate the outcomes and complications of surgically treated very low PPDFFs using double-locked plate fixation.

MATERIALS AND METHODS

Between January 2013 and December 2018, sixty-one consecutive patients with PPDFFs have been conducted. Only Su type III PPDFFs with double-locked plate fixation through a lateral minimally invasive approach and a medial subvastus approach to the distal femur were analyzed. Patients were encouraged to perform straight leg raising exercises and active knee motion on the second postoperative day. Assisted weight bearing from the early postoperative days was supported, and full weight-bearing was allowed after healing the fracture site. All patients were evaluated according to the time to union, limb alignment, range of knee motion, Knee Society Score, and presence of complications.

RESULTS

Twenty one patients (17 females and 4 males, mean age 76 years, range 56-90) were included in the study. There were 10 of 33-A1, 6 of 33-A2 and 5 of 33 A3 fractures, according to the AO classification. Of 21 patients, 20 achieved union at an average of 14 weeks postoperatively. Postoperative limb alignment was satisfactory in all cases, with an average mechanical distal lateral femur angle of 89° and average mechanical posterior distal femur angle of 86°. All patients recovered the knee joint motion similar to that of the contralateral side, and daily life pre-injury. The average knee and function scores were 94 and 89, respectively. There were one case of non-union and three cases of superficial wound infection, which resolved after intravenous antibiotic therapy.

CONCLUSIONS

Double locked plating showed excellent radiographic and functional outcomes with few complications in patients with very low PPDFFs. Based on these promising results, we propose the consideration of double-locked plate fixation in the treatment of very low PPDFFs.

Periprosthetic Fractures Through Tracking Pin Sites Following Computer Navigated and Robotic Total and Unicompartmental Knee Arthroplasty: A Systematic Review

BACKGROUND

Use of computer-assisted navigation (CAN) and robotic-assisted (RA) surgery in total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) both necessitate the use of tracking pins rigidly fixed to the femur and tibia. Although periprosthetic fractures through tracking pin sites are rare, there is a paucity of literature on this potential complication. Therefore, the purpose of this study was to perform a systematic review of the current literature to assess the incidence and clinical outcomes of periprosthetic fractures through tracking pin sites following CAN and RA TKA and UKA.

METHODS

A systematic review was performed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines using the PubMed, MEDLINE, and Cochrane databases in April 2020. Studies were assessed for the presence of pin site fractures, fracture characteristics, and clinical outcomes.

RESULTS

Seventeen clinical studies (5 case series, 1 cohort study, and 11 case reports) involving 29 pin-related fractures were included for review. The overall incidence ranged from 0.06% to 4.8%. The mean time from index arthroplasty to fracture was 9.5 weeks (range, 0 to 40 weeks). The majority of fractures occurred in the femoral diaphysis (59%). Nineteen fractures (66%) were displaced and 10 (34%) were nondisplaced or occult. The majority of cases were atraumatic in nature or involved minor trauma and were typically preceded by persistent leg pain. A transcortical pin trajectory, large pin diameter (>4 mm), diaphyseal fixation, multiple placement attempts, and the use of non-self-drilling, non-self-tapping pins were the most commonly reported risk factors for pin-related periprosthetic fractures following CAN or RA TKA.

CONCLUSIONS

Surgeons should maintain a high index of suspicion for pin-related fractures in patients with ongoing leg or thigh pain after CAN or RA TKA in order to avoid fracture displacement and additional morbidity. As CAN and RA TKA have unique complication risks, the debate regarding the value of technology-assisted TKA and its cost-effectiveness continues.

LEVEL OF EVIDENCE

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

Intraoperative Femoral Condyle Fracture during Bone Preparation in a Cruciate-retaining Primary Total Knee Arthroplasty

Introduction

Intraoperative fracture in revision knee arthroplasty is commonly described. Intraoperative fracture during primary total knee arthroplasty (TKA) is a significant yet infrequently reported complication. The literature about intraoperative fractures during primary TKA is limited. It is usually seen in posterior-stabilized prosthesis during primary TKA, however, its occurrence in cruciate-retaining (CR) primary TKA is rarely reported.

Case Report

The authors describe a unique case of intraoperative medial femoral condyle fracture in primary CR TKA during bone preparation. The fracture was managed successfully by fixation with a 3.5 mm screw followed by cemented primary CRTKA. Bony union was achieved with a good clinical outcome as shown by the Knee Society Knee Score of 86 and a Function Score of 90 without any signs of prosthesis failure/loosening at 2 years' follow-up.

Discussion

Careful pre-operative evaluation and planning are necessary for patients with risk factors to avoid poor outcome. A stable internal fixation abiding the standard principles of fracture fixation and arthroplasty is needed to achieve a satisfactory functional and radiographic outcome, thus avoids early prosthetic failure.

An Exploratory Study of the Texture Research Investigational Platform (TRIP) to Evaluate Bone Texture Score of Distal Femur DXA Scans - A TBS-Based Approach

Poor bone status is associated with increased complications following orthopedic surgery. Therefore, assessing site-specific skeletal status prior to or after orthopedic surgery to optimize outcomes is appealing. The trabecular bone score (TBS) approach, a surrogate for microarchitecture, was adapted to the Texture Research Investigational Platform (TRIP), which allows assessment of many skeletal sites imaged by various modalities. TRIP generates a bone texture score (TBS ORTHO), which could potentially guide surgical decision-making and offer insight into postsurgical fracture risk. As distal femur bone loss occurs following total knee arthroplasty (TKA), we hypothesized that TBS ORTHO after TKA would identify poorer texture in the operated femur compared to the nonoperated. We evaluated 30 subjects (15 M/15 F) with unilateral TKA 2-5 yr previously, mean age 67.9 yr and body mass index 30 kg/m². Using a Lunar iDXA, lumbar spine and entire femur scans were obtained, the latter using the atypical femur fracture feature. Distal femur bone mineral density (BMD) and TBS ORTHO were obtained using manual regions of interest (ROI) at 15% and 25% of leg length from the intercondylar notch. TBS ORTHO was determined using distal femur DICOM images and TRIP v1.0 (Medimaps, France). Differences in operated vs nonoperated femur were evaluated by paired t test. As previously reported, operated leg BMD was approx 10% lower at 15% and 25% ROIs. Similarly, TBS ORTHO values in the operated leg were approx 5% lower (p < 0.05) at these same ROIs. Distal femur TBS ORTHO and BMD were largely unrelated. TBS ORTHO reproducibility at these ROIs was approx 3.5%. In conclusion, this pilot study documents the feasibility of reproducibly obtaining distal femur TBS ORTHO values. Lower values were observed in the surgical leg, consistent with the bone loss that follows TKA. Further work is indicated to refine TRIP use and evaluate whether such data provides guidance for surgical decision-making and improves periprosthetic fracture prediction.

Distal Femoral Replacements for Acute Comminuted Periprosthetic Knee Fractures: Satisfactory Clinical Outcomes at Medium-Term Follow-up

Background

Fracture fixation techniques of comminuted periprosthetic distal femoral fractures have high risk of complications. The aim of this study was to evaluate short- to medium-term outcomes of comminuted periprosthetic distal femoral fractures treated with distal femoral replacements (DFR) at a tertiary arthroplasty unit.

Methods

Retrospective consecutive study of all patients who underwent DFR for periprosthetic fractures with minimum 2-year follow-up between 2010 and 2018. Clinical outcomes, surgical complications, revision for any cause, loosening, Knee Society Score and mortality data were collected at final follow-up.

Results

Thirty patients with average age 81 years (range, 65-90; 6 males and 24 females) were included. All had comminuted fractures (Rorabeck type-2/3). All patients had cemented DFRs. Three patients (10%) with multiple comorbidities died postoperatively. Average time from admission to being fit for discharge was 9 days (range, 3-14). Clinical outcomes and follow-up were available for 27 patients with a median follow-up duration of 4 years (2-13 years). Complication rate was 7.4% with one reoperation, change of polyethylene insert. None of the components have been revised to date. Average Knee Society Score at final follow-up was 78 (range, 57-92) with median arc of motion flexion-extension being 100° (range, 60°-125°).

Conclusions

In our experience, DFRs for comminuted periprosthetic fractures allow immediate mobilization and rehabilitation leading to satisfactory clinical outcomes with low complication rate for this challenging group of patients.

Level of evidence

level IV.

Medial femoral condyle fracture during an Oxford unicompartmental knee replacement surgery: case report

Oxford unicompartmental knee arthroplasty has been used as a good alternative for medial unicompartmental osteoarthritis due to its association with early rehabilitation and a low rate of intraoperative complications. This case describes a rare complication during the procedure of an intraoperative fracture of the medial condyle that was treated with osteosynthesis with 6.5 mm cannulated screws and a compression technique. The patient followed a non-weight-bearing protocol for 6 weeks and reached full range of motion at 3 months. Complete radiological fusion and good functional outcome were observed. Intraoperative fractures can benefit from stable osteosynthesis that allows free range of motion and does not jeopardise the final surgical result.

Contradictory working length effects in locked plating of the distal and middle femoral fractures-a biomechanical study

BACKGROUND

Working length have been reported to affect the plate stress and fixation stiffness. However, the results of previous studies have been controversial. The present study was to determine working length effects on different locations of femoral bone gap.

METHODS

Five composite femurs with wide bone gaps at five levels (G1, 2, 3, 5, and 7), were fixed with locking plates. G1-3, G5 and G7 represented gaps at distal femur, distal-middle femur and middle femur respectively. Strain gauges were applied near the screw holes. The plate-bone constructs were loaded through a hemicylinder on the femoral head with total constraints at the distal femur. The micro-strains, axial stiffness and interfragmentary motions were recorded. Then the locking screws were removed one by one and the tests were re-run. The working length effects were compared and correlated.

FINDINGS

In distal femurs (G1-3), long working length was negatively correlated with the highest strains (r = -0.97, -0.95 and - 0.95, p < 0.01) and axial stiffness (r = -1, -0.96 and -0.99, p < 0.01). In distal-middle femurs (G5), as the working length increased, the highest strain decreased initially and then increased (r = 0.81, p = 0.026) and the axial stiffness decreased (r = -0.98, p < 0.01). In middle femurs (G7), the highest strain and gap motions were much higher than that in the other groups and not significantly correlated with the working length change.

INTERPRETATION

Long working length could reduce the highest plate strain in distal femurs, but had no significant effects in middle femurs. The working length effects were markedly affected by the loading and boundary conditions.

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.

Management of periprosthetic fractures of knee arthroplasty with revision surgery

Objective

As periprosthetic knee fractures are becoming common with the increase in incidence of primary and revision total knee arthroplasty, their management and treatment have become important. The current study aims to evaluate the revision knee arthroplasty carried out due to the failure of primary treatment of periprosthetic femoral fractures.

Methods

The study was conducted from May 2012 to September 2019 at Orthopedics department of Xinjiang Medical University; out of 21 patients 11 were women and 10 men aged 44 to 80 (mean, 70.76 ± 8.31) years who underwent revision surgery for periprosthetic fractures of 19 distal femur, 1 patellar, and 1 proximal tibial fracture. Nineteen cases had definite trauma history leading to periprosthetic fracture, and 2 cases had fracture during post-operative functional exercise. All patients had revision surgery with extended stems with either constrained or limited condylar knee prosthesis.

Results

The duration of follow-up averaged 4.3 years. The Hospital for Special Surgery (HSS) knee score before fracture averaged 91 + 7.01 points (89-95 points) and 85.5 + 6.18 points (81-90 points) at the last follow-up. The average range of motion of knee joint before fracture was 115.7 [+7.6] (110 [~126]), and 101.3 [+9.8] (85 [~115]) at the last follow-up. There was no significant statistical difference. No complications such as infection, component loosening or nonunion. 2 patients had lower extremity vein thrombosis.

Conclusion

Revision surgery of the knee for the periprosthetic fractures with proper prosthetic selection can attain good outcomes after primary total knee arthroplasty. Reasonable and correct procedure is the main principle for a successful operation. The benefits and applicability of revision TKA is the reconstructive solution for the issues of prosthetic knee fractures, is highly recommended.

Periprosthetic fractures about total knee arthroplasty

Periprosthetic fracture after total knee arthroplasty presents a difficult complication for many orthopaedic surgeons. These fractures occur most frequently around the distal femur followed by the patella and then tibia. These fractures are frequently complicated by poor bone quality or compromised bone due to the presence of the implants. Surgical treatment is typically necessary and requires varied techniques of open fixation, intramedullary fixation, or revision arthroplasty. Outcomes of these injuries vary widely. This review aims to describe the epidemiology, classification, treatment options and outcomes for periprosthetic fractures following total knee arthroplasty.

Locking plates versus retrograde intramedullary nails in the treatment of periprosthetic supracondylar knee fractures. A retrospective multicenter comparative study

INTRODUCTION

Biomechanical studies demonstrated the superiority of retrograde supracondylar intramedullary nails (RIN) against locking plates (LP) for the treatment of periprosthetic supracondylar femoral fractures (PSFs); however, clinical results are still conflicting. This study aimed to compare LP and RIN, as well as, cemented and uncemented nails in the treatment of PSFs regarding fracture healing, complications and functional results.

MATERIALS AND METHODS

A retrospective multicenter analysis of 60 PSFs classified as Rorabeck type I or II was performed. Thirty-one cases were treated with LP while in 29 cases RIN were used. Out of the latter, 14 had nailed cementoplasty, while 15 an uncemented nail.

RESULTS

The two groups were comparable concerning gender, ASA score, operated side, follow-up time, fracture type and mechanism of injury. The LP was significantly younger than the RIN group. Forty-six cases had fracture union at an average of six months, 11 were healed between seven and twelve months (delayed unions), and three developed non-unions. There was no significant difference in the median union time between RIN and LP groups (six vs five months, p = 0.707) or cemented and uncemented nailing groups (5.5 vs six months, p = 0.354). The RIN group had fewer delayed unions or non-unions than LP group; however, not reaching significance (4 vs 10, p = 0.190). Complications were fewer but non-significantly different between cemented and uncemented nails (one vs five, p = 0.481). The mean postoperative flexion was comparable between RIN and LP groups (99.1° vs 94.9°, p = 0.547) or cemented and uncemented nails (102° vs 96.3°, p = 0.4). The mean Oxford Knee Score did not differ between LP and RIN groups (30.8 vs 31.3, p = 0.93) as well as between cemented and uncemented nails (31.5 vs 30.6, p = 0.801).

DISCUSSION

PSFs with good bone stock can be treated equally with LP or RIN. Nails demonstrated advantages concerning the fracture healing potential. Orthopaedic surgeons need to be trained in both treatment options to manage PSFs. Cemented nails may increase stability and healing capacity in elderly osteoporotic patients; however, further studies are needed.

A case series of mortality and morbidity in distal femoral periprosthetic fractures

Periprosthetic distal femoral fractures are occurring in increasing numbers. There is limited research into outcomes and mortality. This study aimed to assess the 1 year mortality and complications requiring further surgery in the two years following a presentation with a periprosthetic distal femoral fracture. A retrospective case series of periprosthetic distal femoral fractures at a single trauma centre was undertaken. All patients were included who presented with a distal femur periprosthetic fracture between 1st January and 2008 and 31st March 2015. 60 patients with 49 females and 11 males. Mean age was 80.7. Median time to surgery was 63 h 42 (70%) underwent open reduction internal fixation, 13 (21.7%) underwent revision arthroplasty and 5 (8.3%) underwent non-operative treatment. Median length of stay was 14 days. There were 12 (20%) complications requiring further surgery within 2 years. There were 2 (3.3%) deaths in 30 days and 8 (13.3%) within 1 year following fracture. Periprosthetic distal femoral fractures are becoming a common orthopaedic presentation. They occur in a complex group of patients and have high rates of mortality and complications.

Clinical outcomes in periarticular knee fractures with flexible fixation using far cortical locking screws in locking plate: a prospective study

PURPOSE

Periarticular fractures around the knee joint are treated traditionally by locking plates which provide excellent stability but suppress callus formation. Far cortical locking (FCL) screws allow axial motion and enhance uniform callus formation. Our study aims to evaluate the outcomes of FCL screws in traditional locking plate in periarticular fractures of the knee.

METHODS

Thirty patients with periarticular fractures of the knee joint were operated with locking plate using FCL screws. All patients were evaluated clinically and radiographically using X-rays at 6, 12, 24 weeks, 1 year and with CT scan at 12-weeks follow-up.

RESULTS

The average time for complete union was 20 weeks in tibial fractures and 24 weeks in femur fractures. Average time to full weight bearing ambulation was 4.8 ± 0.93 weeks. One patient had delayed union in which union was complete after 9 months.

CONCLUSION

This study shows that FCL screws in locking plates allow uniform callus formation and fracture union with minimal complication rates.