Periprosthetic Distal Femur Fracture after Total Knee Arthroplasty: A Systematic Review

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.

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.

Clinical differences between periprosthetic and native distal femur fractures: a comparative observational study

INTRODUCTION

The incidence of periprosthetic distal femur fractures (PDFF) is increasing as the number of total knee replacements becomes more common. This study compared the demographics, fracture characteristics, treatment, and outcomes of periprosthetic versus native distal femur fractures (NDFF).

MATERIALS AND METHODS

This was a retrospective cohort study of patients ≥ 18 who underwent surgical fixation of NDFF or PDFF from 2012 to 2020 at a level-1 trauma center. The main variables collected included demographics, AO/OTA fracture classification, fixation construct, concomitant fractures, polytrauma rates, bone density, and reduction quality. Primary outcomes were unexpected return to the operating room (UROR), hospital length of stay, and quality of reduction. T-tests, Fisher's exact tests, and multivariate analyses were used for statistical analysis.

RESULTS

209 patients were identified, including 70 PDFF and 139 NDFF. PDFF patients were elderly females (81%) with isolated (80%) and comminuted (85%) 33 A.3 (71%) fractures. NDFF patients included 53% females, were commonly middle-aged, and displayed comminuted (92%) 33 C.2 fractures. 48% of NDFF patients had concomitant fractures. Intramedullary nailing was the primary fixation for both groups, followed by nail-plate combination (37%) for PDFF and lateral locking plates (21%) for NDFF. NDFF patients experienced significantly longer hospital stays, higher UROR rates, and worse quality of reduction (p < 0.05). PDFF patients had a significantly greater prevalence of low bone density (p < 0.05).

CONCLUSION

PDFF occur as isolated injuries with significant metaphyseal comminution in elderly females with low bone quality. NDFF commonly occurs in younger patients with less metaphyseal comminution and concomitant fractures. Intramedullary nailing was the most common treatment for both groups, although preference for nail-plate combination fixation is increasing. NDFF type 33 C fractures are at greater risk of UROR.

Management of periprosthetic femoral fractures following total knee arthroplasties using locking plates or intramedullary nailing. Comparative study of 567 cases

INTRODUCTION

Proximal femur fractures in elderly patients pose a common problem that requires surgical management. The main objective of this study was to compare the results of treatment by locked plate (LP) and by anterograde (AIN) or retrograde (RIN) intramedullary nailing. The secondary objective was to analyze the complications related to each group. The hypothesis of this study was that the radiological and clinical results of each group were comparable.

MATERIALS AND METHODS

The data of 438 patients from 8 centers were studied retrospectively with 365 LP and 69 cases of intramedullary nailing (49 AIN and 20 RIN). The groups were comparable in terms of mean age (75±2years), mean preoperative Parker score (5.3±0.5) and mean KOOS score (74±2). Most patients lived at home before their fracture [n=375 (86%)]. At follow-up, the joint range of motion, the KOOS and Parker scores, living premises, the time required to regain full weight-bearing, the time required for consolidation as well as the reduction alignment: frontal, sagittal, horizontal.

RESULTS

The average follow-up was: 79±2weeks (65 to 82). The functional and radiological results were comparable, although nailing allowed a faster return to weight-bearing (1±2weeks for nailing versus 7±2weeks for LP, p=0.048) and a better postoperative Parker score (5.5±0.5 for nailing versus 4.7±0.2 for LP, p=0.045). Rotational malalignment in femoral nailing was often in the direction of internal rotation, compared to the LP (p=0.045). Complications were comparable with the exception of mortality, which was more frequent for LP [22.5% in the LP group versus 13% in the nailing group (p=0.045)]. Complications were categorized as: mechanical complications 6.8% of LP, 5.7% of nailing (p>0.05), infections [11% of LP, 5.8% of nailing (p>0.05)], surgical revisions [2% of LP, 10% of nailing (p>0.05)].

DISCUSSION AND CONCLUSION

The hypothesis was refuted. These results show that nailing conferred a faster recovery of weight-bearing, a better Parker score, and is associated with a lower mortality rate. The morbidity rate is comparable between the two techniques. Indeed, when the indication for osteosynthesis by LP or by nailing is made, and both choices are technically justifiable, it would be prudent to favor the technique, which carries the least risk, which in this case is nailing. This conclusion must, however, be taken in to consideration with regard to the reduced number of nailing. A larger series of nailing, particularly retrograde, would be necessary to be able to confirm this last difference between the 2 groups.

LEVEL OF EVIDENCE

IV; comparative retrospective study.

Therapy aspects of peri-implant femoral fractures-a retrospective analysis of 64 patients

PURPOSE

The incidence of peri-implant femoral fractures (PIFF) is increasing. Information regarding outcomes, timing of surgery, risk factors, and a clinically applicable treatment algorithm are lacking. The aim of this study was to identify outcome-related risk factors and to derive a treatment algorithm.

METHODS

Sixty-four PIFFs treated between 01.01.2006 and 31.12.2020 in a level I trauma centre were evaluated retrospectively for fracture pattern, surgical technique, risk factors, complications, and 1-year mortality. The study was approved by the ethics committee (No. 21-2714-104).

RESULTS

One-year mortality was 24.1%. Surgical complications occurred in 4.7%, and general complications in 15.6% of the patients. General complications, low haemoglobin level at admission, elevated CHA2DS2-VASc, and Charlson score resulted in increased 1-year mortality. Time to surgery > 24 h did not increase complication or mortality rates. The three predominant fracture patterns were fractures close or distal to cephalomedullary nails, close or proximal to distal lateral plates, and close or distal to sliding hip screws. Recommendations for surgical treatment were derived: Osteosynthesis should enable as much weight-bearing as possible; the initial implant should only be removed, if this is essential for the new osteosynthesis; lateral locking plates should span the whole femur; antegrade nails should have a cephalomedullary component to avoid consecutive femoral neck fractures; implants should overlap to reduce the risk of consecutive inter-implant fractures.

CONCLUSION

Risk factors for 1-year mortality in patients with PIFFs were identified. A treatment algorithm and general principles for surgery of PIFFs were developed.

Load transfer in bone after partial, multi-compartmental, and total knee arthroplasty

Introduction: Arthroplasty-associated bone loss remains a clinical problem: stiff metallic implants disrupt load transfer to bone and, hence, its remodeling stimulus. The aim of this research was to analyze how load transfer to bone is affected by different forms of knee arthroplasty: isolated partial knee arthroplasty (PKA), compartmental arthroplasty [combined partial knee arthroplasty (CPKA), two or more PKAs in the same knee], and total knee arthroplasty (TKA). Methods: An experimentally validated subject-specific finite element model was analyzed native and with medial unicondylar, lateral unicondylar, patellofemoral, bi-unicondylar, medial bicompartmental, lateral bicompartmental, tricompartmental, and total knee arthroplasty. Three load cases were simulated for each: gait, stair ascent, and sit-to-stand. Strain shielding and overstraining were calculated from the differences between the native and implanted states. Results: For gait, the TKA femoral component led to mean strain shielding (30%) more than three times higher than that of PKA (4%-7%) and CPKA (5%-8%). Overstraining was predicted in the proximal tibia (TKA 21%; PKA/CPKA 0%-6%). The variance in the distribution for TKA was an order of magnitude greater than for PKA/CPKA, indicating less physiological load transfer. Only the TKA-implanted femur was sensitive to the load case: for stair ascent and gait, almost the entire distal femur was strain-shielded, whereas during sit-to-stand, the posterior femoral condyles were overstrained. Discussion: TKA requires more bone resection than PKA and CPKA. These finite element analyses suggest that a longer-term benefit for bone is probable as partial and multi-compartmental knee procedures lead to more natural load transfer compared to TKA. High-flexion activity following TKA may be protective of posterior condyle bone resorption, which may help explain why bone loss affects some patients more than others. The male and female bone models used for this research are provided open access to facilitate future research elsewhere.

Minimally invasive surgery of femoral periprosthetic fractures increases the rate of consolidation and decreases time to bone healing without a higher rate of complications

BACKGROUND

Knee periprosthetic femoral fractures (KPPFF) are becoming more frequent due to the increasing number of arthroplasties and the aging population, for whom maintaining autonomy and function remains a challenge. The use of locking plates has improved functional results and promoted the development of "minimally invasive" surgical (MIS) approaches. Despite the availability of literature comparing between different types of osteosynthesis for KPPFF, there is a paucity of information available on the complications of osteosynthesis using locking plates, depending on the approach. We therefore carried out a retrospective multicenter study (nine centers: Dijon, Grenoble, Lille, Marseille, Nice, Paris, Saint-Étienne, Strasbourg, Colmar) as part of a Symposium of the French Society of Orthopedic Surgery and Traumatology (SOFCOT). Following osteosynthesis of KPPFF by locking plates carried out by a standard approach or by a minimally invasive approach (MIS), the objectives were: (1) to compare the complications, (2) to evaluate whether the radiological and clinical results (rate and time of consolidation, resumption of weight bearing, lack of reduction, postoperative autonomy) were comparable in the two groups.

HYPOTHESIS

The hypothesis was that performing an MIS approach in these indications does not confer more complications than a standard approach, and rather, the MIS approach offers better functional and radiological results.

MATERIAL AND METHOD

Five hundred and seventy-three patients presented with KPPFF over the periods studied (retrospective series from January 2012 to December 2016, then prospective series from January to December 2019). After applying the inclusion criteria (KPPFF by locking plate) and exclusion criteria (tumor context, infectious, intraoperative fractures, fractures on loose prostheses, other osteosynthesis methods, treatment by prosthetic revision, patients under the age of 18, follow-up less than 1-year, incomplete files), a global series of 306 patients was retained. Two groups were created according to the approach performed: a standard approach group (S, n=228) and a minimally invasive approach group (MIS, n=78). The demographic data of the population were recorded, as was the criteria for autonomy (Parker score, place of living). Postoperative complications were sought (infection, mechanical complication, surgical revision). Finally, the radiological and clinical results were evaluated (rate of, and time to consolidation, resumption of weight bearing, lack of reduction, postoperative autonomy).

RESULTS

The comparison of the two subgroups, S and MIS, found complication rates are comparable in the two groups in terms of infections [S group: n=18 (7.9%), MIS group: n=2 (2.6%)], mechanical complications [S: n=23 (10.1%), MIS: n=2 (2.6%)], and surgical revision [S: n=33 (14.5%), MIS: n=7 (8.9%)], and a lack of difference in postoperative autonomy [Parker; S group: 4.7±2.4 (0-9) vs. MIS group: 5±2, 7 (0-9)]. On the other hand, the time to return to weight bearing was shorter in the MIS group [4.3±3.5weeks (0-12) versus 10.1±10.1weeks (0-110), p<0.001]. The rate of nonunion was lower in the MIS group [n=1 vs. n=20, i.e. 1.7% vs. 11.1% (p=0.031)] and the time to consolidation was shorter [7.5±4.3weeks (6-30) versus 15.2±9.4weeks (5-78) (p<0.001)].

CONCLUSION

Performing an MIS approach in the management of KPPFF by locking plate osteosynthesis does not cause any more complications than a standard approach. In addition, higher consolidation rates can be obtained in shorter periods of time. This study suggests that it proposing osteosynthesis using the MIS approach as a primary surgery is a reasonable choice when treatment using locking plates is chosen for a KPPFF, subject to technical expertise.

LEVEL OF EVIDENCE

III; observational study.

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%.

Surgery Within 24 Hours Reduces Mortality and General Complication Rates in Patients Who Have Periprosthetic Femoral Fractures at the Hip

BACKGROUND

In patients who have hip fractures, treatment within 24 hours reduces mortality and complication rates. A similar relationship can be assumed for patients who have hip periprosthetic femoral fractures (PPFs) owing to the similar baseline characteristics of the patient populations. This monocentric retrospective study aimed to compare the complication and mortality rates in patients who had hip PPF treated within and after 24 hours.

METHODS

In total, 350 consecutive patients who had hip PPF in a maximum-care arthroplasty and trauma center between 2006 and 2020 were retrospectively evaluated. The cases were divided into 2 groups using a time to surgery (TTS) of 24 hours as the cutoff value. The primary outcome variables were operative and general complications as well as mortalities within 1 year.

RESULTS

Overall, the mean TTS was 1.4 days, and the 1-year mortality was 14.6%. The TTS ≤ 24 hours (n = 166) and TTS > 24 hours (n = 184) groups were comparable in terms of baseline characteristics and comorbidities. Surgical complications were equally frequent in the 2 groups (16.3 versus 15.2%, P = .883). General complications occurred significantly more often in the late patient care group (11.4 versus 28.3%, P < .001). In addition, the 30-day mortality (0.6 versus 5.5%, P = .012), and 1-year mortality (8.3 versus 20.5%, P = .003) rates significantly increased in patients who had TTS > 24 hours. Cox regression analysis yielded a hazard ratio of 4.385 (P < .001) for the TTS > 24 hours group.

CONCLUSIONS

Prompt treatment is required for patients who have hip PPF to reduce mortality and overall complications.

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.

Distal Femur Replacement: An Option for Osteoporotic Fractures in the Elderly

Background A distal femur fracture (DFF) around the native or prosthetic knee is commonly seen in the osteoporotic elderly population. Surgical management is required to restore the function. Fracture fixation requires a period of restricted weight-bearing; however, distal femoral replacement (DFR) allows immediate weight-bearing and quicker recovery. Methods All patients who underwent distal femur replacement from 2020 to 2023 at our hospital were retrospectively reviewed. Data related to the patient's demographics, medical comorbidities, preinjury mobility status, perioperative management and length of stay were collected. Results Eleven patients with 13 distal femoral replacements were included. There were 10 periprosthetic and 3 native fractures around the distal femur. Two patients had bilateral periprosthetic fractures. The median age was 84 years (range 62-95) with all patients being females. Eight patients were living in their homes while three were care home residents. The median duration of surgery was 120 min. The mean blood loss was 350 ml. Patients were mobilised out of bed at a median of three days and were able to walk for 2 meters with a frame at a mean of 10 days (range 3-15) except for two patients whose mobility was limited to the chair. The mean length of hospital stay was 32 days (range 8-54). All patients were discharged back to their original destination except for one who was shifted to a care home instead of her own home. Conclusion In our opinion, distal femur replacement provided a more favourable outcome with respect to pain management, early rehabilitation with full weight-bearing immediately following the surgery and fewer complications. Furthermore, in our hands, the surgical time was short with limited blood loss.

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 Fractures After a Total Knee Arthroplasty

As the number of total knee arthroplasties performed continues to increase, complications such as postoperative periprosthetic fractures are becoming increasingly more common. Femoral periprosthetic fractures are the most common type of fractures around a total knee arthroplasty, whereas tibial and patellar periprosthetic fractures are infrequent. Treatment principles depend on the bone the fracture is located, the status of the implant fixation, bone stock, and the type of implants available. The Vancouver classification allows for a standardized system to describe and manage these injuries, incorporating these factors. A systematic approach is vital in obtaining the best possible outcomes because complications and mortality rates mimic those of hip fractures.

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.

Treatment of Bifocal Periprosthetic Fractures above and below a Knee after Tumor using Spanning Ilizarov Device: A Case Report

Introduction

Multiple treatment options and internal and external devices have been recommended for periprosthetic fractures management around total knee arthroplasty.

Case Report

We present the case of the high-energy bifocal periprosthetic fractures of the femur and the tibia after total knee prosthesis following excision of a tumor. One of the fractures was an open tibial fracture Gustilo Type IIIB and the other - comminuted subtrochanteric fracture of the femur with extrusion of periprosthetic cement pieces out from the bone defect. The Ilizarov circular external fixator was used for the skeletal stabilization and early functional treatment in this compound case.

Conclusion

The use of Ilizarov external fixator for patients with complex periprosthetic fractures, who present severe technical difficulties in bone stabilization, especially by concomitant severe soft-tissue damage after high-energy injuries, is a good surgical alternative.

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

Background

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

Methods

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

Results

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

Conclusions

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

Awareness of Stress Concentration Points for Prevention and Management of Periprosthetic Fractures Following Plate Installation Reinforcement: A Case Report

Introduction

In an aging society, the incidence of periprosthetic fractures will increase owing to the increasing number of patients undergoing joint replacement surgery. We experienced a case of recurrent periprosthetic fracture in a patient who had undergone ipsilateral hip bipolar hemiarthroplasty (BHA) and total knee arthroplasty. Based on our experience, we discuss the treatment strategy for periprosthetic fractures in patients at a high risk of fall.

Case Report

An 84-year-old woman, who had undergone total knee arthroplasty 9 years ago and ipsilateral hip BHA 2 years ago, sustained a knee condylar fracture (Su classification type III) due to fall. This knee periprosthetic fracture posed a challenge for osteosynthesis; therefore, revision total knee arthroplasty was performed using a hinge-type prosthesis. During this surgery, we installed a reinforcement plate on the femoral shaft to prevent fractures because of the short stem tip distance between the hip and knee prosthesis (53 mm). The procedure was successful, and the patient regained her walking ability. However, 6 months after surgery, the patient sustained a hip periprosthetic fracture (Vancouver type B2) due to a fall, despite precautionary plate installation. In case of hip stem insertion, the stress caused by fall is concentrated on the infratrochanteric region, as reflected in her fracture site. From a mechanical perspective, this fracture was not accidental. The plate reinforcement procedure may have been inadequate because the top of the plate was located at the infratrochanteric region.

Conclusion

Periprosthetic fractures may occur despite the installation of a plate for fracture prevention. With a total hip arthroplasty or hip BHA stem inserted, a fall could result in a subtrochanteric fracture.

Iodine-supported implants in prevention and treatment of surgical site infections for compromised hosts: a prospective study

BACKGROUND

Surgical site infection (SSI) is a common complication following orthopedic implantation. We developed an iodine coating for titanium implants to reduce implant-related infections and conducted a prospective clinical study to evaluate the efficacy and potential drawbacks of iodine-supported implants.

PATIENTS AND METHODS

Between July 2008 and July 2017, 653 patients (377 male and 27 female patients; mean age, 48.6) with postoperative infection or a compromised status were treated using iodine-loaded titanium implants. The mean follow-up period was 41.7 months. In 477 patients, iodine-supported implants were used to prevent infection and in 176 patients, to treat active infection (one-stage surgery, 89 patients; two-stage surgery, 87 patients). In the limbs and pelvis, the primary diagnoses included the following: 161 tumors, 92 deformities/shortening, 47 pseudarthrosis, 42 fractures, 32 infected TKA, 25 osteoarthritis, 21 pyogenic arthritis, 20 infected THA, and 6 osteomyelitis. In the spinal cases, there were 136 cases of tumors, 36 cases of pyogenic spondylitis, and 35 cases of degeneration. Five modes of implant failure were identified and classified as follows: soft tissue failure (type 1), aseptic loosening (type 2), structural failure (type 3), infection (type 4), and tumor progression (type 5).

RESULTS

The overall failure rate in our series was 26.3% (172/653). There were 101 mechanical failures, including 22 type 1, 20 type 2, and 59 type 3 failures. Non-mechanical causes accounted for 71 failures, including 45 type 4 and 26 type 5 failures. The overall incidence of infections was 6.8%. The mean time to the onset of infection after implantation was 9.1 months. The overall infection rate was 3.7% in the prevention cases and 15.3% in the treatment cases. There was no difference between one-stage replacement (14.6%) and two-stage replacement (16.0%). There were 11 cases of treatment for SSI of spine surgery, and the re-infection rate was 0% using iodine-coated instruments.

CONCLUSIONS

The five modes of failure of the iodine-supported implant were satisfactory compared with previous reports. In particular, because the infection rate of iodine-coated implants used for compromised hosts is low compared with other methods, postoperative infection is more easily controlled. It can be considered highly effective for spinal infections that require one-stage revision surgery.

LEVEL OF EVIDENCE IV

Trial registration Prospective, Observation study.

Treatment of periprosthetic knee infection and coexistent periprosthetic fracture: A case report and literature review

BACKGROUND

Periprosthetic joint infection (PJI) and periprosthetic fracture (PPF) are among the most serious complications following total knee arthroplasty. Herein, we present one patient with these two complications with details on the characteristics, treatment strategy, and outcome.

CASE SUMMARY

A 69-year-old female patient who suffered from PJI and PPF following total knee arthroplasty was treated by a two-stage revision surgery. After thorough foreign material removal and debridement, we used a plate that was covered with antibiotic-loaded bone cement to link with a hand-made cement spacer to occupy the joint space and fix the fracture. Although the infection was cured, the fracture did not heal and caused bone defect due to the long interval between debridement and revision. In the revision surgery, a cemented stem and cortical allogenic splints were used to reconstruct the fracture and bone defect. At the final follow-up 27 mo after revision, the patient was satisfied with postoperative knee functions with satisfactory range of motion (104º) and Hospital for Special Surgery knee score (82 points). The radiographs showed no loosening of the prosthesis and that the bone grafts healed well with the femur.

CONCLUSION

Our two-stage revision surgery has proved to be successful and may be considered in other patients with PJI and PPF.

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.

Novel classification system for periprosthetic distal femoral fractures: a consideration for comminution

PURPOSE

Comminution is an aspect of periprosthetic distal femoral fractures (PDFFs) that can influence postoperative outcomes and treatment selection, but is not included in current classification systems. We propose a new classification system for PDFFs based on comminution and cortical reads. This study aims to prove its reliability and efficacy to predict fracture severity and guide treatment.

METHODS

A retrospective chart review of patients treated with single or dual locking plates for PDFFs was performed. Two fellowship-trained orthopedic joint reconstruction specialists used available imaging to classify each PDFF as either type 1 (minimal or no comminution allowing for reconstruction of medial and lateral cortices), type 2 (comminution reasonably allowing for reconstruction of either medial or lateral cortex), and type 3 (extensive comminution not allowing reasonable reconstruction of medial or lateral cortex). Each PDFF was then analyzed for radiographic outcomes including lateral distal femoral angle (LDFA) and the posterior distal femoral angle (PDFA).

RESULTS

Interobserver reliability assessed by Cohen's Kappa statistic was 0.707, and average intraobserver reliability was 0.843, showing substantial reliability. Type 3 PDFFs had greater varus deformity than type 1 (p = 0.0457) or 2 (0.0198).

CONCLUSION

The proposed classification system accounts for comminution, demonstrates strong interobserver and intraobserver reliability, and can be used to guide treatment in regard to single versus dual plating.

LEVEL OF EVIDENCE

Retrospective comparative study, Level IV.

Short-term outcomes of periprosthetic compared to native distal femur fractures, a national database study

BACKGROUND

Distal femur fractures (DFFx) are highly morbid injuries with a complication rate comparable to hip fractures. Rising rates of total knee arthroplasty (TKA) have led to increasing rates of periprosthetic DFFx (pDFFx). We sought to determine how pDFFx complication rates differed from native DFFx (nDFFx).

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) was used to identify patients who sustained pDFFx or nDFFx between 2012 and 2018. Patients were further stratified by operative treatment: open reduction internal fixation (ORIF) or distal femur replacement (DFR). Multivariate logistic regression was used to compare 30-day complication rates between pDFFx versus nDFFx and, among pDFFx patients, ORIF versus DFR or revision TKA (rTKA).

RESULTS

563 patients with pDFFx and 2259 patients with nDFFx were identified between 2012 and 2018. pDFFx patients had significantly lower rates of ORIF than nDFFx patients (36.4 vs 95.4%, p < 0.001). On multivariate analysis, pDFFx were associated with a higher rate of surgical site complications (OR 2.48, p = 0.009) compared to nDFFx. There were no differences in mortality, reoperations, major complications, rate of blood transfusion, venous thromboembolism and disposition. In patients with pDFFx, patients undergoing DFR/rTKA were more likely to be discharged home versus a rehab facility, compared to those undergoing ORIF (OR 2.62, p < 0.001).

CONCLUSIONS

In this first large registry study comparing pDFFx and nDFFx, we find similar outcomes between these groups in the first 30 days after surgery. Patients with pDFFx did have higher rates of surgical site complications, including infection and dehiscence. In pDFFx patients, those undergoing DFR were more likely to return home post-operatively.

Modified fixation for periprosthetic supracondylar femur fractures: Two case reports and review of the literature

BACKGROUND

Periprosthetic supracondylar femoral fractures (PSFs) present a challenge in terms of optimizing fixation in patients with poor bone quality. Surgical treatment and peri-operative management of PSFs in the elderly remain a burden for orthopedic surgeons. Among different treatment options, locking plate (LP) and retrograde intramedullary nail (RIMN) have shown favorable results. However, reduced mobility and protected weight-bearing are often present in the postoperative older population. With a purpose of allowing for early weight-bearing, a modified nail plate combination (NPC) was redesigned for PSF management.

CASE SUMMARY

In our cases, two elderly osteoporotic female underwent total knee arthroplasty (TKA), and then suffered from low energy trauma onto their knees after falling to the floor. Plain radiographs or computed tomography scans demonstrated oblique or transverse PSFs, both of which occurred at the distal femur above TKA. The modified NPC technique was performed for treatment of PSFs. The patient was made foot flat weight bearing in 1 wk. At 6-mo follow-up, the union was ultimately achieved using modified NPC with satisfactory implant outcomes.

CONCLUSION

Neither LP nor RIMN alone may provide adequate support to allow for union in circumstances where the patient has severely osteopenic bone. Therefore, developing a modified implant offer an alternative choice for treating PSFs. These two cases revealed that this technique is a viable option for the geriatric osteoporotic PSFs, offering safe, early weight bearing and favorable clinical outcomes.

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.

Outcomes of dual plating for unstable distal femoral fractures: a subgroup comparison between periprosthetic and non-periprosthetic fractures

PURPOSE

This study aimed to evaluate the outcomes of dual plating for unstable distal femoral fractures via a subgroup analysis between periprosthetic and non-periprosthetic fractures.

METHODS

This retrospective cohort study analyzed the outcomes of dual plating for unstable distal femoral fractures among 49 consecutive patients (43 women and 6 men) enrolled from July 2008 to August 2020. The patients were divided into periprosthetic (group P, n = 29) and non-periprosthetic (group N, n = 20) groups. The radiographic outcomes included the mechanical lateral distal femoral angle (mLDFA) and union rate based on the computed tomography findings. The clinical parameters included the knee range of motion and knee society score (KSS).

RESULTS

The mean patient age was 71.1 years, and the average follow-up period was 37 months (range, 12-138 months). Union was achieved in 47 patients (96%). The average final mLDFA was 90.5° in group P and 88.3° in group N. The average final knee range of motion was 130° in group P and 107° in group N. The average final KSS was 73.8 in group P and 87.1 in group N.

CONCLUSION

Dual plating for distal femoral fractures yielded an excellent union rate and limb alignment with a low complication rate.

Early peri-implant fractures after distal femur fracture locked plating?

PURPOSE

To report the peri-implant fracture rates after locked plating of distal femur fractures and examine risk factors.

METHODS

Over a 7 year period, 89 AO/OTA 33A/C distal femur fractures were identified and reviewed. After excluding treatment with intramedullary nails, age under 50, those with the proximal femur protected, or those without 6 months of follow-up, 42 distal femur fractures in 41 patients, mean age 72.3 were studied. All were treated with lateral locked plating of distal femur fractures. The details of the constructs were recorded. Mean follow-up was 562 days (18.7 months).

RESULTS

3/42 were open injuries, 9/42 were type C, 16/42 were type A, and 17 were periprosthetic above a knee arthroplasty. Two patients were treated with a dynamic plating construct using all far-cortical locking (FCL) screws in the diaphysis. 40 patients were treated with a variety of non-dynamic diaphyseal constructs including locking, non-locking, and four with 1-2 FCL screws distally. There was one asymptomatic nonunion. 2/2 patients in the dynamically plated group experienced a peri-implant fracture versus 1/40 in the non-dynamically plated group (p = 0.001). 3/9 with an all-locked construct versus 0/25 patients with a most proximal non-locking screw experienced a fracture.

CONCLUSIONS

The overall peri-implant fracture risk was 7.1% (3/42), 3/17 patients with a locking screw most proximal experienced a peri-implant fracture, 3/9 with an all-locking construct, and 2/2 patients with a dynamic construct experienced a fracture. These findings merit additional clinical and biomechanical study.

Successful Plate Fixation with Long Intramedullary Fibula Bone Graft for Periprosthetic Femur Fracture: A Case Report

Background and objectives: Treatment of a displaced or comminuted periprosthetic distal femur fracture is challenging, especially in patients with osteoporosis. In this case report, we shared our successful surgical experience of using a long intramedullary fibula bone graft in a plate fixation surgery for a periprosthetic distal femur fracture in an extremely elderly patient with osteoporosis. Case report: A 95-year-old woman with severe osteoporosis (bone mineral density level: −3.0) presented with right knee pain and deformity after a fall, and a right periprosthetic distal femur fracture was identified. The patient underwent an open reduction and an internal plate fixation surgery with the application of a long intramedullary fibular bone graft. Due to a solid fixation, immediate weight-bearing was allowed after the surgery. She could walk independently without any valgus or varus malalignment or shortening 3 months after the surgery. A solid union was achieved 4 months postoperatively. Conclusions: We present a case wherein a long intramedullary allogenous fibula strut bone graft was used successfully to treat a right periprosthetic femur fracture in an extremely elderly patient. A long allogenous fibula bone graft can act not only as a firm structure for bridging the bone defect but also as a guide for precise component alignment. We believe this treatment option for periprosthetic fractures is beneficial for achieving biological and mechanical stability and facilitates early mobilization and weight-bearing for the patient.

Does distance from joint line influence complications after distal femur fractures in native and periprosthetic knees?

BACKGROUND

Distal femur fractures are projected to increase in incidence secondary to an aging population and growing utilization of total knee arthroplasty. Surgical management is the standard of care, but optimal treatment for far distal fractures is still unclear. Our study investigates if there are distal femur fractures too distal to be treated with lateral locked plating in periprosthetic fractures.

METHODS

One hundred and ten consecutive patients treated with locked plating for distal femur fractures around a total knee replacement were identified using CPT codes. Fractures were classified by length of the distal fracture segment and Su classification. Complications studied were nonunion, malunion, infection, further fracture related surgery, readmission within 90 days, and mortality within 1 year of surgery. Sixty six fractures met inclusion criteria of 180 days of follow-up or sustaining a complication prior to180 days.

RESULTS

The size of the distal fracture segment and Su classification did not correlate with increased complication rate in periprosthetic distal femur fractures.

CONCLUSIONS

There was no difference between complications following lateral locked plating of distal femur fractures based on the size of the distal fracture segment in periprosthetic fractures. Lateral locked plating is an effective treatment modality for these fractures regardless of how distal the fracture extends.

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.

The geriatric distal femur fracture: nail, plate or both?

Surgical fixation of distal femur fractures in geriatric patients is an evolving topic. Unlike hip fractures, treatment strategies for distal femur fractures are ill-defined and lack substantive high-quality evidence. With an increasing incidence and an association with significant morbidity and mortality, it is essential to understand existing treatment options and their supporting evidence. Current fixation methods include the use of either retrograde intramedullary nails, or plate and screw constructs. Due to the variability in fracture patterns, the unique anatomy of the distal femur, and the presence or absence or pre-existing implants, decision-making as to which method to use can be challenging. Recent literature has sought to describe the advantages and disadvantages of each, however, there is currently no consensus on a standard of care, and little randomized evidence is available that directly compares intramedullary nails with plating. Future randomized studies comparing intramedullary nails with plating constructs are necessary in order to develop a standard of care based on injury characteristics.

Comparable Outcomes Between Native and Periprosthetic Fractures of the Distal Femur

Despite the rising prevalence of arthroplasty and aging population, limited data exist regarding differences in periprosthetic fracture clinical outcomes compared with native counterparts. This study compares differences in hospital treatment, morbidity, and mortality associated with periprosthetic distal femur fractures at an urban level 1 trauma center. We retrospectively reviewed all adult AO/OTA type 33 fractures (526) that presented to our institution between 2009 and 2018. In total, 54 native and 54 periprosthetic fractures were matched by age and gender. We recorded demographics, operative measures, length of stay (LOS), discharge disposition, and mortality. We used McNemar's and paired t-tests for analysis where appropriate (p < 0.05) (IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY; IBM Corp.). The average age at injury was 74 years ± 12 (native) compared with 73 years ± 12 (periprosthetic). After 1:1 matching, the groups had similar body mass index (31.01 vs. 32.98, p = 0.966 for native and periprosthetic, respectively) and mechanisms of injury with 38 native and 44 periprosthetic (p = 0.198) fractures from low-energy falls. Both groups had 51/54 fractures managed with open reduction internal fixation with a locking plate. The remaining were managed via amputation or intramedullary nail fixation. Mean operative time (144 minutes (±64) vs. 132 minutes (±62), p = 0.96) and estimated blood loss (319 mL (±362) vs. 289 mL (±231), p = 0.44) were comparable between the native and periprosthetic groups, respectively. LOS: 9 days ± 7 (native) versus 7 days ± 5 (periprosthetic, p = 0.31); discharge disposition (to skilled nursing facility/rehab): n = 47 (native) versus n = 43 (periprosthetic, p = 0.61); and mortality: n = 6 (native) versus n = 8 (periprosthetic, p = 0.55). No significant differences were observed. We found no statistical differences in morbidity and mortality in periprosthetic distal femur fractures treated over 10 years at a level 1 trauma center. Native and periprosthetic AO/OTA type 33 distal femur fractures are serious injuries with similar outcomes at a level 1 trauma center.

Deep Learning-Based Muscle Segmentation and Quantification of Full-Leg Plain Radiograph for Sarcopenia Screening in Patients Undergoing Total Knee Arthroplasty

Sarcopenia, an age-related loss of skeletal muscle mass and function, is correlated with adverse outcomes after some surgeries. Here, we present a deep-learning-based model for automatic muscle segmentation and quantification of full-leg plain radiographs. We illustrated the potential of the model to predict sarcopenia in patients undergoing total knee arthroplasty (TKA). A U-Net-based deep learning model for automatic muscle segmentation was developed, trained and validated on the plain radiographs of 227 healthy volunteers. The radiographs of 403 patients scheduled for primary TKA were reviewed to test the developed model and explore its potential to predict sarcopenia. The proposed deep learning model achieved mean IoU values of 0.959 (95% CI 0.959–0.960) and 0.926 (95% CI 0.920–0.931) in the training set and test set, respectively. The fivefold AUC value of the sarcopenia classification model was 0.988 (95% CI 0.986–0.989). Of seven key predictors included in the model, the predicted muscle volume (PMV) was the most important of these features in the decision process. In the preoperative clinical setting, wherein laboratory tests and radiographic imaging are available, the proposed deep-learning-based model can be used to screen for sarcopenia in patients with knee osteoarthritis undergoing TKA with high sarcopenia screening performance.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Retrograde Intramedullary Nailing and Locked Plating for the Treatment of Periprosthetic Supracondylar Femur Fractures: A Meta-Analysis and Quantitative Review

BACKGROUND

As the prevalence of Total Knee Arthroplasty increases, there is still debate over the preferred method of treatment of supracondylar periprosthetic femoral fractures. The aim of this study was to compare two of the common methods of fixation: Locked Plating and Retrograde Intramedullary Nailing with respect to nonunion, delayed union and surgical revision rate.

METHODS

A comprehensive database search via Pubmed was conducted, yielding 16 eligible studies. Six of those studies were comparative and were used in the meta-analysis section. All 16 studies were used in the pooled sample analysis section. The primary outcome analyzed was nonunion and delayed union rate while the secondary outcome was the surgical revision rate. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by comparing incidences of nonunion and delayed union, and surgical revision rates among the studies.

RESULTS

The meta-analysis showed that there is no statistically significant difference among the two groups in terms of nonunion and delayed union rate (OR = 1.43, CI = 0.74, 2.74, P=0.28), but there is a significant difference in the surgical revision rate favoring locked plating over retrograde intramedullary nailing (OR = 2.71, CI = 1.42, 5.17, P=0.003). The pooled sample analysis showed that there is no significant difference in the nonunion and delayed union rates (P=0.210) or the surgical revision rates (P=0.038).

CONCLUSION

Both locked plating and Retrograde Intramedullary Nailing are reliable options for treating supracondylar femoral fractures around Total Knee Arthroplasty. Locked plating demonstrated a trend towards decreased nonunion and delayed union rates and a significantly lower surgical revision rate in the meta-analysis.

The value of megaprostheses in non-oncological fractures in elderly patients: A short-term results

INTRODUCTION

The management of both hip and distal femur fractures as well as periprosthetic fractures can be challenging for orthopaedic surgeons. The use of megaprosthetic implants could provide substantial advantages in elderly population affected by complex fractures. The aim of the study was to evaluate the effectiveness of megaprosthetic implants for treating hip and distal femur fractures as well as periprosthetic fractures in elderly.

MATERIAL AND METHODS

From January 1st 2015 to December 31st 2019, patients treated for proximal or distal femoral fractures with severe bone loss or failure of previous surgery were retrospectively reviewed. Patients were divided into two group based on diagnosis: proximal femur fractures (group A) and distal femur fractures (group B). Subsequently, patients underwent hip (group A) or knee (group B) megaprosthesis. Self-assessed questionnaires were administered to all patients pre and postoperatively. Primary outcome was the Activity Daily Living. Secondary outcomes were: Instrumental Activity Daily Living, Short Form-12, Oxford knee or hip score, complications. Charlson score, Harris classification for hip or Anderson Orthopaedic Research Institute score and complication were recorded. All patients underwent a radiological follow up to rule out implant loosening and mobilization. Pre and postoperative functional score comparisons in each group were undertaken. Significance was set p ≤ 0.05.

RESULTS

Twelve patients were finally included in the study. There were 6 male and 6 females, the mean age was 72,9 years old (± 7,4); the mean BMI was 29,8 points (± 4.5). The mean follow-up was 2.9 years (± 1.4). No differences could be found between pre and postoperative evaluation in each group. No aseptic loosening, dislocation, mobilization or radiolucency were recorded during the follow-up. In group A, two surgical site infections (2/6 patients) and one pneumonia (1/6 patients) were recorded. In group B, two surgical site infections occurred (2/6 patients). All patients were treated by antimicrobial oral therapy with complete regression.

CONCLUSION

The use of hip and knee megaprosthetic implants in traumatology is a safe and viable option in elderly patients.

A modified anterolateral swashbuckler approach for distal femoral fractures: description and outcomes

BACKGROUND

The treatment of distal femur fractures represents a challenging task. General and local factors, including bone quality, articular surface involvement, fracture comminution, associated soft tissue injuries and ultimately fixation system, all play a role in the final clinical outcome. Current surgical approaches often undermine patellar vascularization and integrity of the extensor apparatus, not guaranteeing sufficient visualization of the medial condyle. This technical note presents the efficacy and safety a new surgical technique to address distal femoral fractures.

METHODS

The original "swashbuckler" surgical approach was modified in order to obtain a better visualization of the lateral and medial femoral condyles without affecting the knee extensor mechanism and the anastomotic arterial supply of the patella. This modified surgical approach was utilized in a consecutive series of patients presenting with an AO Foundation/Orthopaedic Trauma Association (AO/OTA) 33 distal femur or periprosthetic fracture of the knee. The final outcome was recorded according to a functional evaluation scoring system.

RESULTS

Twelve patients (2 males and 10 females) with a mean age of 67,8 years were included in this series. The same, modified "swashbuckler" surgical approach was applied in all cases. Multiple internal fixation techniques, including a single lateral plate, a combination of a lateral and medial plate, a single lateral plate associated with lag screws, were used to obtain a satisfactory stabilization of the fracture site. All patients were reviewed at a minimum one-year follow up (median 15 months): all patients regained their level of activities of daily living. No major intraoperative or postoperative complications were recorded.

CONCLUSIONS

The modified swashbuckler approach allows anatomical reduction and appropriate fixation without sacrificing the blood supply to the patella and ensures rapid weight bearing resumption thanks to an intact extensor mechanism.

To Fix or Revise: Differences in Periprosthetic Distal Femur Fracture Management Between Trauma and Arthroplasty Surgeons

INTRODUCTION

This study sought to determine the effect of trauma fellowship training on the surgical decision to fix or revise to distal femoral replacement in periprosthetic distal femur fractures.

METHODS

An anonymous online survey including nine cases of geriatric periprosthetic distal femur fractures was distributed through the Orthopaedic Trauma Association website. Respondents were asked whether they would recommend fixation or revision to distal femoral replacement. Fractures were classified by the location relative to the anterior flange (proximal or distal) and the presence or absence of comminution. Recommendations were compared between type of fellowship completed (trauma, arthroplasty, or both), practice setting, and number of periprosthetic distal femur fractures treated monthly.

RESULTS

One hundred fifty-one surgeon survey responses were included. Completion of a trauma fellowship was associated with a higher likelihood of recommending fixation for any periprosthetic distal femur fracture compared with arthroplasty training (odds ratio [OR] 2.55, 95% confidence interval [CI] 1.97 to 3.29; P < 0.0001). Disagreement was significant for comminuted proximal (OR 6.90, 95% CI 3.24 to 14.68; P < 0.0001), simple distal (OR 20.90, 95% CI 6.41 to 67.71; P < 0.001), and comminuted distal fractures (OR 2.47, 95% CI 1.66 to 3.68; P < 0.0001). Dual fellowship-trained surgeons were less likely to recommend fixation than surgeons who completed a trauma fellowship alone (OR 0.60, 95% CI 0.39 to 0.93; P = 0.027) and more likely to recommend fixation than surgeons who completed an arthroplasty fellowship alone (OR 1.70, 95% CI 1.13 to 2.63; P = 0.012). Surgeons who treat three or more periprosthetic distal femur fractures monthly showed a significant preference for fracture fixation compared with lower volume surgeons (OR 2.45, 95% CI 1.62 to 3.68; P < 0.0001).

DISCUSSION

Fellowship-trained trauma surgeons show a notable preference for fracture fixation over distal femoral replacement for periprosthetic distal femur fractures, as compared with arthroplasty-trained surgeons. Additional research is needed to clarify surgical indications that maximize outcomes for these injuries.

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.

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

OBJECTIVES

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

DATA SOURCES

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

STUDY SELECTION

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

DATA EXTRACTION

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

DATA SYNTHESIS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

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

Current Reconstruction Options in Periprosthetic Fractures Around the Knee

Background:

Periprosthetic fractures are a rare complication after total knee arthroplasty (TKA). However, the incidence of these fractures is growing after the increasing number of TKAs performed every year and the progressive aging of the population. In addition, the surgical treatment and peri-operative management of these complications are demanding, representing a challenge for the orthopedic surgeon.

Significance:

A thorough understanding of these fractures and a correct classification are necessary in order to select the most suitable surgical treatment. The aim of this review was to analyze the epidemiology, classification, diagnosis, surgical treatment, and outcomes of periprosthetic knee fractures in order to give an exhaustive overview.

Results:

Reduction and internal fixation with locking plates or intramedullary nails represents the preferred option in case of a stable prosthetic implant. Conversely, in case of loose tibial and/or femoral component, implant revision is mandatory. Conservative treatment is rarely indicated.

Conclusion:

A deep understanding of the characteristics and patterns of periprosthetic knee fractures, and the determination of the stability of the prosthetic implant are necessary in order to establish the correct treatment.

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.

Early complications and reoperation rates are similar amongst open reduction internal fixation, intramedullary nail, and distal femoral replacement for periprosthetic distal femur fractures: a systematic review and meta-analysis

BACKGROUND

Our purpose was to perform a systematic review and meta-analysis to evaluate complication and revision rates for periprosthetic distal femur fractures (PPDFF) treated with: (1) ORIF using periarticular locking plates (ORIF), (2) retrograde intramedullary nail (IMN), and (3) distal femoral replacement (DFR).

METHODS

Systematic review of the literature was performed to identify eligible studies (N = 52). Identified treatment groups were: ORIF (N = 1205 cases), IMN (N = 272 cases), and DFR (N = 353 cases). Median follow-up was 30 months (range 6-96 months). Primary outcomes were: (1) major complication rates and (2) reoperation rates over the follow-up period. Secondary outcomes were incidence of deep infection, periprosthetic fracture, mortality over the follow-up period, 1-year mortality, non-union, malunion, delayed union, and hardware failure. Data for primary and secondary outcomes were pooled and unadjusted analysis was performed. Meta-analysis was performed on subset of individual studies comparing at least two of three treatment groups (N = 14 studies). Odds-ratios and their respective standard errors were determined for each treatment group combination. Maximum likelihood random effects meta-analysis was conducted for primary outcomes.

RESULTS

From the systematic review, major complication rates (p = 0.55) and reoperation rates (p = 0.20) were not significantly different between the three treatment groups. DFR group had a higher incidence of deep infection relative to IMN and ORIF groups (p = 0.03). Malunion rates were higher in IMN versus ORIF (p = 0.02). For the meta-analysis, odds of major complications were not significantly different between IMN versus DFR (OR 1.39 [0.23-8.52]), IMN versus ORIF (OR 0.86 [0.48-1.53]), or the ORIF versus DFR (OR 0.91 [0.52-1.59]). Additionally, odds of a reoperation were not significantly different between IMN versus DFR (OR 0.59 [0.08-4.11]), IMN versus ORIF (OR 1.26 [0.66-2.40]), or ORIF versus DFR (OR 0.91 [0.51-1.55]).

CONCLUSIONS

There was no difference in major complications or reoperations between the three treatment groups. Deep infection rates were higher in DFR relative to internal fixation, malunion rates were higher in IMN versus ORIF, and periprosthetic fracture rates were higher in DFR and IMN versus ORIF.

Peri-implant fractures of the upper and lower extremities: a case series of 61 fractures

PURPOSE

To assess outcomes for patients who sustained peri-implant fractures (PIFs).

METHODS

Medical records of patients who sustained a PIF were reviewed for demographic, injury, outcome, and radiographic data. PIFs were classified using a reproducible system and stratified into cohorts based on fracture location. Clinical outcomes were evaluated for each cohort.

RESULTS

Fifty-six patients with 61 PIFs with at least 6 months of follow-up were included. The mean age of the cohort was 60.4 ± 19.5 years. Twenty-two (36.1%) PIFs occurred in males, while 39 (63.9%) occurred in females. Fifty-two (85.2%) PIFs were sustained from a low-energy injury mechanism. PIFs were most often treated with plate/screw constructs (50.8%). Complications included: 6 (9.8%) nonunions, 5 of which were successfully treated to healing, 5 (8.2%) fracture related infections (FRI), and 1 (1.6%) hardware failure. Sixty (98.4%) PIFs ultimately demonstrated radiographic healing.

CONCLUSION

PIFs are usually treated surgically and have a relatively high incidence of complications, with nonunion in femoral PIFs being the greatest. Despite this, the rate of ultimate healing is quite high.

Periprosthetic Tibial Fractures After Total Knee Arthroplasty: Early and Long-Term Clinical Outcomes

BACKGROUND

Although periprosthetic fractures are increasing in prevalence, evidence-based guidelines for the optimal treatment of periprosthetic tibial fractures (PTx) are lacking. Thus, the purpose of this study is to assess the clinical outcomes in PTx after a total knee arthroplasty (TKA) which were treated with different treatment options.

METHODS

A retrospective review was performed on a consecutive series of 34 nontumor patients treated at 2 academic institutions who experienced a PTx after TKA (2008-2016). Felix classification was used to classify fractures (Felix = I-II-III; subgroup = A-B-C) which were treated by closed reduction, open reduction/internal fixation, revision TKA, or proximal tibial replacement. Patient demographics and surgical characteristics were collected. Failure of treatment was defined as any revision or reoperation. Independent t-tests, one-way analysis of variance, chi-squared analyses, and Fisher's exact tests were conducted.

RESULTS

Patients with Felix I had more nonsurgical complications when compared to Felix III patients (P = .006). Felix I group developed more postoperative anemia requiring transfusion than Felix III group (P = .009). All fracture types had >30% revision and >50% readmission rate with infection being the most common cause. These did not differ between Felix fracture types. Patients who underwent proximal tibial replacement had higher rate of postoperative infection (P = .030), revision surgery (P = .046), and required more flap reconstructions (P = .005).

CONCLUSION

PTx after a TKA is associated with high revision and readmission rates. Patients with Felix type I fractures are at higher risk of postoperative nonsurgical complications and anemia requiring transfusion. Fractures treated with proximal tibial replacement are more likely to develop postoperative infections and undergo revision surgery.

Locked compression plating versus retrograde intramedullary nailing in the treatment of periprosthetic supracondylar knee fractures: a systematic review and meta-analysis

Background

Periprosthetic fractures of the distal femur above a total knee arthroplasty (TKA) have traditionally been managed by locking compression plating (LCP). This technique is technically demanding and is associated with high rates of non-union and revision. More recently, retrograde intramedullary nailing (RIMN) has been proposed as an acceptable alternative. This meta-analysis aims to evaluate clinical outcomes in patients with periprosthetic supracondylar femoral fractures who were treated with LCP and RIMN.

Methods

An up-to-date literature search was carried out using the pre-defined search strategy. All studies that met the inclusion criteria were assessed for methodological quality with the Cochrane’s collaboration tool. Operative time, functional score, time-to-union, non-union rates and revision rates were all considered.

Conclusion

Ten studies with a total of 531 periprosthetic fractures were included. This meta-analysis has suggested that there is no significant difference in any of the outcome measures assessed. Further, more extensive literature is required on the subject to draw more robust conclusions.

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.

[Locking plate fixation of distal periprosthetic femoral fractures : Clinical outcome and mortality]

Hintergrund

Die Versorgung distaler periprothetischer Femurfrakturen (PFF) stellt aufgrund des geriatrischen Patientenkollektivs eine große interdisziplinäre Herausforderung dar und erfolgt (abhängig vom Frakturtyp) häufig mittels winkelstabiler Plattenosteosynthese (WPO), wobei bisher nur wenige Daten zum klinischen Outcome existieren. Ziel der Untersuchung ist die Identifikation von Risikofaktoren für ein schlechtes Outcome und erhöhte Mortalität.

Methoden

In dieser retrospektiven Studie wurden 36 Fälle mit distaler PFF untersucht. Eingeschlossen wurden nur Versorgungen mit WPO. Neben relevanten Vorerkrankungen (ASA-Score, Charlson Index), der Frakturmorphologie und relevante Komplikationen, wurden u.a. die 1- und 3-Jahres-Mortalität, sowie das klinische Outcome mit Hilfe des Lysholm-Scores erfasst.

Ergebnisse

Die 1- und 3- Jahres Mortalität betrug 9% bzw. 26%, wobei dies ausschließlich ASA 3 und 4 Patienten betraf. Der Lysholm Score zeigte eine hohe Variabilität (65 ± 27 Punkte) mit höheren Werten in der ASA 1-2 Subgruppe (82 vs. 63 Punkte) aber unabhängig vom Frakturtyp. Als Risikofaktoren für die 3-Jahres Mortalität konnten der präoperative ASA-Score, der Charlson Komorbiditätsindex und das Patientenalter identifiziert werden.

Diskussion

Die dargestellte Fallserie weist eine hohe absolute Mortalitätsrate auf, auch wenn diese im Vergleich zu bisher publizierten Daten, etwas geringer war. Die Rate an Sekundärdislokationen, fehlender Frakturheilung oder Folgeoperationen war ebenfalls gering. Die WPO erscheint daher als geeignete Versorgung für Frakturen mit stabiler Prothese. Jedoch besteht eine hohe Variabilität im klinischen Outcome unabhängig vom Frakturtyp, sowie signifikant erhöhte Mortalitätsraten bei vorerkrankten Patienten.

Biomechanical evaluation of the docking nail concept in periprosthetic fracture fixation around a stemmed total knee arthroplasty

Intramedullary femoral nails provide an ideal mechanical axis for periprosthetic fracture fixation. Slotted nails allow a connection to a total knee arthroplasty (TKA) stem. This study aims to compare implant and construct stiffness, interfragmentary movement and cycles to failure between an antegrade slotted femoral nail construct docked to a TKA stem and a distal femoral locking plate in a human periprosthetic femoral fracture model. In eight pairs of fresh-frozen human femora with stalked TKA, a 10 mm transverse osteotomy gap was set simulating a Rorabeck type II, Su type I fracture. The femora were pairwise instrumented with either an antegrade slotted nail coupled to the prosthesis stem, or a locking plate. Cyclic testing with a progressively increasing physiologic loading profile was performed at 2 Hz until catastrophic construct failure. Relative movement at the osteotomy site was monitored by means of optical motion tracking. In addition, four-point bending implant stiffness, torsional implant stiffness and frictional fit of the stem-nail connection were investigated via separate non-destructive tests. Intramedullary nails exhibited significantly higher four-point bending and significantly lower torsional implant stiffness than plates, P < 0.01. Increasing difference between nail and stem diameters decreased frictional fit at the stem-nail junction. Nail constructs provided significantly higher initial axial bending stiffness and cycles to failure (200 ± 83 N/mm; 16'871 ± 5'227) compared to plate constructs (93 ± 35 N/mm; 7'562 ± 1'064), P = 0.01. Relative axial translation at osteotomy level after 2'500 cycles was significantly smaller for nail fixation (0.14 ± 0.11 mm) compared with plate fixation (0.99 ± 0.20 mm), P < 0.01. From a biomechanical perspective, the docking nail concept offers higher initial and secondary stability under dynamic axial loading versus plating in TKA periprosthetic fracture fixation.