Management and outcome of periprosthetic fractures after total knee arthroplasty

Chronic Oral Corticosteroid Use and 10-Year Incidence of Major Complications Following Total Knee Arthroplasty

BACKGROUND

Oral corticosteroids are the primary treatment for several autoimmune conditions. The risk of long-term implant, bone health, and infectious-related complications in patients taking chronic oral corticosteroids before total knee arthroplasty (TKA) is unknown. We compared the 10-year cumulative incidence of revision, periprosthetic joint infection (PJI), fragility fracture (FF), and periprosthetic fracture following TKA in patients who had and did not have preoperative chronic oral corticosteroid use.

METHODS

A retrospective cohort analysis was conducted using a national database. Primary TKA patients who had chronic preoperative oral corticosteroid use were identified using Current Procedural Terminology and International Classification of Disease 9 and 10 codes. Exclusion criteria included malignancy, osteoporosis treatment, trauma, and < 2-year follow-up. Primary outcomes were 10-year cumulative incidence and hazard ratios (HRs) of all-cause revision (ACR), aseptic revision, PJI, FF, and periprosthetic fracture. A Kaplan-Meier analysis and a multivariable Cox proportional hazards model were utilized. Overall, 611,596 patients were identified, and 5,217 (0.85%) were prescribed chronic corticosteroids. There were 10,000 control patients randomly sampled for analysis.

RESULTS

Corticosteroid patients had significantly higher 10-year HR of FF (HR; 95% confidence interval); P value (1.47; 1.34 to 1.62; P < .001)], ACR (1.21; 1.05 to 1.40; P = .009), and PJI (1.30; 1.01 to 1.69; P = .045) when compared to the control.

CONCLUSIONS

Patients prescribed preoperative chronic oral corticosteroids had higher risks of ACR, PJI, and FF within 10 years following TKA compared to patients not taking corticosteroids. This information can be used by surgeons during preoperative counseling to educate this high-risk patient population about their increased risk of postoperative complications.

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.

Surgical outcomes of subtypes of periprosthetic tibia fractures after total knee arthroplasty

Surgical outcomes of subtypes of periprosthetic tibia fractures after total knee arthroplasty were evaluated by using the Felix et al. classification system. Type 3 fractures were the most common classification of periprosthetic tibial fractures. Type 2 fractures had the highest rates of revision and nonunion. Type 3 fractures exhibited longer healing times than types 2 and 4. Far type 3 fractures showed the longest healing time of all fracture types but had very minimal complications. Type 4 fracture managed by K-wire/cerclage wire may require hardware removal or debridement but exhibited the shortest healing time compared to types 2 and 3.

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.

Outcomes of periprosthetic distal femur fractures following total knee arthroplasty: Intramedullary nailing versus plating

BACKGROUND

Periprosthetic distal femur fractures (PPDFFs) present a challenge in terms of optimizing fixation in patients with poor bone quality and limited bone stock. The main treatment options include laterally based plating and intramedullary nailing. We hypothesized that treatment of PPDFFs with intramedullary nails would result in improved union rate, fewer complications, and an equivalent rate of malalignment compared to plating.

MATERIALS AND METHODS

Cases of PPDFFs were identified through a query of our institutional trauma database between 2011-2018. Adult patients (>18 years) were included if they sustained a fracture of the distal femur around a total knee arthroplasty (TKA) that was not initially treated at another institution. The anatomic lateral distal femoral angle (aLDFA) and the anatomic posterior distal femoral angle (aPDFA) were measured on the follow-up radiographs.

RESULTS

Ninety-seven PPDFFs in 97 patients, with a mean age of 76 years and 74% female were identified. Plating was used in 74 patients (76%) and 23 patients (24%) were treated with intramedullary nailing. Extension deformity in the sagittal plane was more common following intramedullary nailing compared to plating (10/23 nailing versus 10/74 plating) (p=0.002). There were 12 reoperations (12/75, 16%), and the method of fixation was not associated with rate of reoperation (p=0.9).

CONCLUSION

Intramedullary nailing was associated with an increased risk of malalignment, most commonly an extension deformity, in this series. However, malalignment was not associated with worse outcomes.

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.

Sister, Sister! Siblings With Simultaneous Early Femoral Insufficiency Fractures After Total Knee Arthroplasty

Early periprosthetic fractures after total knee arthroplasty are rare but devastating complications which require revision surgery and lead to poor patient satisfaction. We present 2 siblings who underwent primary total knee arthroplasty on the same day and then both presented 2 weeks after surgery with atraumatic periprosthetic femur fractures. The first patient underwent revision for a cemented distal femoral replacement with stemmed tibial fixation. The second patient underwent an isolated femoral component revision with a stemmed femoral component and distal augment. Histological evaluation identified significant peri-implant osteoporosis. The variation in complexity associated with early periprosthetic femoral insufficiency fractures is highlighted by these 2 cases. Surgeons may consider using stemmed femoral components in similar patients if poor distal femoral bone stock is encountered intraoperatively.

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.

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.

Periprosthetic tibial fracture after total knee arthroplasty with popliteal artery injury-A case report

We present the case of a 79-year-old woman who presented at our center with a periprosthetic tibial fracture with a popliteal artery injury after total knee arthroplasty. Anastomosis of the popliteal artery was performed on the day of injury, and was later treated by open reduction and internal fixation. The patient was able to walk 3 months after injury. The present case was difficult to treat because of the arterial injury associated with periprosthetic fracture. Although revision of the implant was considered, open reduction and internal fixation was selected because of the severity of soft-tissue damage. The mechanism of injury is not uncommon, and it is expected that similar fractures will become more prevalent in the future as the number of knee replacement surgeries increases.

Increased Intercondylar Femoral Box Cut-to-Femur Size Ratio During Posterior-Stabilized Total Knee Arthroplasty Increases Risk for Intraoperative Fracture

Background

Iatrogenic intraoperative fractures are preventable complications in total knee arthroplasty. As press-fit fixation becomes more popular, further investigation into risk factors is needed. Some authors have suggested that smaller femurs may be at higher risk in posterior-stabilized constructs owing to industry designs trending toward larger, constant box sizes that increase the amount of bone resection relative to bone stock.

Methods

Finite element analysis (FEA) was used to investigate the effect of insertion of posterior-stabilized femoral components on stress distributions in small femurs and whether common bony preparation techniques could further affect risk for intraoperative fracture. The FEA results were validated with mechanical testing by loading to failure with varying resection depths of the distal femur and varying lateralization of the box cut.

Results

With a standard distal resection depth and neutral box position, a decrease in femur size led to an increase in maximal von Mises stresses by 43.6% medially and 44.3% laterally. Box lateralization and increased distal resection depth had minimal changes on the maximal stresses (3.3% medially and −0.4% laterally) on average-sized femurs while having a much larger effect on the stress distribution in small femurs (118.3% medially and 6.7% laterally).

Conclusions

A subset of intraoperative femur fractures is potentially preventable. Small femur sizes, especially ones that would require increased distal resection or change in implant positioning, may benefit from an alternative design without the need for a cam/post mechanism.

Outcomes and Review of Periprosthetic Tibial Fractures

Periprosthetic fractures around total knee arthroplasties (TKA) are well documented in the literature. Fractures of the tibial side occur least frequently and often pose reconstructive challenges to the treating surgeon. As use of arthroplasty continues to rise, periprosthetic fractures of the tibia will likely become more prevalent. Periprosthetic fracture management is based on recommendations (Mayo classification) made 20 years ago. With newer design technology, the adjuvant use of locking plates in the presence of implant stable periprosthetic tibial fractures (Felix types IIA and IIIA) is unknown. The authors retrospectively reviewed 19 patients who sustained periprosthetic Felix type IIA or IIIA fractures that were treated with operative stabilization using plate and screw constructs. Union rate, time to union, incidence of need for revision on an acute or delayed basis, and restoration of ambulation were investigated. Fourteen patients were followed for the entire course of treatment. Preoperative range of motion was unable to be obtained due to the nature of the injuries. After primary surgical stabilization, 78.6% of the patients obtained successful union of their fracture at a mean of 25 months, but no arthroplasty component revision was necessary in any patient. Three (21.4%) patients required revision surgery, resulting in an overall union rate of 92.9%. Mean time to union in this cohort was 8.4±3.4 months, and the overall complication rate was 28.6%. Treatment of periprosthetic (TKA) tibial fractures carries a relatively high risk of complications and nonunion after primary stabilization, and patients should be counseled accordingly. [Orthopedics. 2020;43(3):182-186.].

Ilizarov external fixation for a periprosthetic tibial fracture in severe osteoporosis: a case report

Background

The incidence of periprosthetic fractures after total knee arthroplasty (TKA) is rising due to the increasing number of TKAs performed annually and the growing elderly population. A periprosthetic fracture of the proximal tibia following TKA is a rare injury that may be a challenging clinical scenario.

Case presentation

The case of an 84-year-old woman who sustained a periprosthetic tibial fracture 10 years after a TKA is presented. This patient had multiple risk factors. The fracture was not deemed amenable to conventional treatment because the bone fragment was too small. This patient underwent fixation of her tibial fracture above the TKA using a five-ring Ilizarov external fixator. This allowed immediate full weight-bearing. The fixator was removed at 12 weeks, at which time the fracture was solidly healed. At the most recent follow-up, 2 years from injury, she was fully weight-bearing without walking aids and had a knee range of motion (ROM) of 0–110°.

Conclusion

To the best of our knowledge, this is the first report in which Ilizarov external fixation has been used for a periprosthetic tibial fracture after TKA.

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.

Interprosthetic femoral fractures: management challenges

Interprosthetic femur fractures are a rare but serious complication following total hip and knee arthroplasty. Classification systems have focused not only on diagnosis but also on treatment algorithm. Critical to the evaluation of patients with these fractures are an assessment of fracture location, bone quality, and the presence of stemmed implants. The gold standard for fracture fixation is locked plating with bicortical and unicortical screws, supplemented with wires or cables as needed. For patients with compromised bone stock or insufficient bony area for fixation, allograft augmentation with struts or interprosthetic sleeves may be used. For fractures with severe bone loss, conversion to a megaprosthesis or total femur replacement may be warranted.

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.

Outcomes of fixation for periprosthetic tibia fractures around and below total knee arthroplasty

INTRODUCTION

The incidence of periprosthetic fractures after total knee arthroplasty (TKA) is rising due to an increasing number of TKAs performed annually and the growing elderly population. Like periprosthetic fractures of the distal femur, periprosthetic tibia fractures are primarily treated with operative fixation; however, there is limited scientific literature that has reported outcomes of periprosthetic tibia fractures treated with modern plating techniques. To our knowledge, this is the largest series of non-intraoperative periprosthetic tibia fractures treated with open reduction internal fixation (ORIF) ever reported.

METHODS

Retrospective chart review of 4557 operatively treated tibia fractures with ORIF over a 16-year period at two Level 1 Trauma Centers.

RESULTS

38 patients with an average follow-up of 15.3 months (range 3-24) were identified. 11 (28.9%) fractures were in the proximal tibia (four with extension into the plateau (Felix 1A) and seven adjacent to the tibial stem (Felix 2A)), six (15.8%) in the midshaft/diaphysis (Felix 3A), and 21 (55.3%) in the distal 1/3rd (metaphysis, Felix 3A). 76.3% (29/38) of fractures united by 6 months following the index procedure, leaving 9 nonunions. The overall re-operation rate was 31.6% (12/38). There were no significant differences in rates of union (p = 1.00), reoperation (p = 0.66), superficial infection (p = 0.66), or deep infection (p = 0.31) in patients treated with single versus dual plating.

CONCLUSION

Periprosthetic tibia fractures are difficult to treat and have a high risk of nonunion and reoperation even with modern plating techniques. Most patients can be treated to union with operative fixation and do not require revision arthroplasty, if the components are stable initially. We recommend dual plating for fractures in the proximal third, and either single plating or nailing for fractures in the middle and distal thirds depending on bone quality, implant positioning, and fracture morphology.

DXA evaluation of femoral bone mineral density and cortical width in patients with prior total knee arthroplasty

Periprosthetic fractures after total knee arthroplasty (TKA) have devastating consequences. Osteoporosis increases periprosthetic fracture risk, but distal femur bone mineral density (BMD) is not measured post-TKA. This study measured distal femur BMD and cortical width; both were lower in the TKA compared to the non-operated leg. BMD measurement reproducibility was good. Standardized DXA regions of interest are proposed.

INTRODUCTION

Periprosthetic fractures following total knee arthroplasty (TKA) are not rare. We hypothesized that TKA is associated with low BMD, potentially increasing periprosthetic fracture risk. However, distal femur dual energy x-ray (DXA) measurement is virtually never performed after TKA due to lack of standardized approaches. Thus, this study's aims were to develop standard DXA femur regions of interest (ROIs), assess cortical width, and determine measurement reproducibility in TKA patients.

METHODS

Thirty adults (15 M/15 F) age 59-80 years with unilateral, primary TKA within 2-5 years had femoral DXA scans performed in duplicate using a Lunar iDXA densitometer. In prior work, we established that femur BMD was lowest in the distal metaphysis and highest in mid-shaft. Thus, BMD and cortical width were measured at 15%, 25%, and 60% of the femur length measured from the distal notch. Femur BMD and cortical width were compared between limbs (TKA vs. non-operated side) by paired t test.

RESULTS

BMD was 3.2-9.9% lower (p < 0.001) in the operated femur at all custom ROIs; substantial between individual differences existed with some up to 30% lower. Cortical width was lower (p < 0.05) at the 25% ROI on the TKA side. BMD reproducibility was excellent; CV 0.85-1.33%.

CONCLUSIONS

Distal femur BMD can be reproducibly measured using DXA and is ~ 10% lower on the TKA leg. Similarly, medial and lateral cortices are thinner at the 25% ROI. These bone changes likely increase periprosthetic fracture risk. Further work to define and mitigate periprosthetic fracture risk after TKA is needed.

Cadaveric study of the infrapatellar branch of the saphenous nerve: Can damage be prevented in total knee arthroplasty?

BACKGROUND

The infrapatellar branch of the saphenous nerve (IPBSN) is a purely sensory nerve innervating the anteromedial aspect of the knee and anteroinferior knee joint capsule. Total knee arthroplasty (TKA) is commonly used to treat end-stage arthritis, but the IPBSN is often injured and results in numbness around the anteromedial knee. The aim of this cadaveric study was to describe the course and variability of the IPBSN and to assess whether it is possible to preserve during a standard midline surgical approach in TKA.

METHODS

Ten fresh-frozen cadaver legs were dissected using a midline approach to the knee. Skin and subcutaneous flap were reflected to expose both the saphenous nerve and its branches. The branches of the IPBSN were identified, and their vertical distances above the tibial tuberosity (TB) were recorded: TB to inferior branch, to middle branch, and to superior branch.

RESULTS

There were 10 left-sided specimens (6 female, 4 male) with a mean age of 79.9 ± 9.8 years. 8 (80%) specimens had 2 branches of IPBSN while 2 (20%) specimens had 3 branches. The average distance from TB to the inferior branch was 16.8 ± 8.3 mm (3.0-28.0); middle branch, 24.0 ± 1.4 mm (23.0-24.9); and superior, 45.9 ± 7.7 mm (32.0-54.5).

CONCLUSION

Our cadaveric study found no consistent way to preserve the IPBSN using a standard midline approach in TKA. It is important to provide proper patient education on this complication, and surgeons should be aware of approximate locations and variations of IPBSN while performing other knee procedures.

Impact of time to surgery from injury on postoperative infection and deep vein thrombosis in periprosthetic knee fractures

PURPOSE

Periprosthetic fracture (PPF) is a serious complication that occurs in 0.3%-2.5% of all total knee arthroplasties used to treat end-stage arthritis. To our knowledge, there are no studies in the literature that evaluate the association between time to surgery after PPF and early postoperative infections or deep vein thrombosis (DVT). This study tests our hypothesis that delayed time to surgery increases rates of postoperative infection and DVT after PPF surgery.

METHODS

Our study cohort included patients undergoing PPF surgery in the American College of Surgeons National Surgical Quality Improvement Program database (2006-2015). The patients were dichotomized based on time to surgery: group 1 with time ≤2 days and group 2 with time >2 days. A 2-by-2 contingency table and Fisher's exact test were used to evaluate the association between complications and time to surgery groups, and multivariate logistic regression was used to adjust for demographics and known risk factors.

RESULTS

A total of 263 patients (80% females) with a mean age of 73.9 ± 12.0 years were identified receiving PPF surgery, among which 216 patients were in group 1 and 47 patients in group 2. Complications in group 1 included 3 (1.4%) superficial infections (SI), 1 (0.5%) organ space infection (OSI), 1 (0.5%) wound dehiscence (WD), and 4 (1.9%) deep vein thrombosis (DVT); while complications in group 2 included 1 (2.1%) SI, 1 (2.1%) OSI, 1 (2.1%) DVT, and no WD. No significant difference was detected in postoperative complications between the two groups. However, patients in group 2 were more likely (p = 0.0013) to receive blood transfusions (57.5%) than those in group 1 (32.4%).

CONCLUSION

Our study indicates patients with delayed time to surgery have higher chance to receive blood transfusions, but no significant difference in postoperative complications (SI, OSI, WD, or DVT) between the two groups.

Periprosthetic Tibial Fractures

Periprosthetic fractures around total knee arthroplasty have become an increasingly common and challenging orthopaedic problem. Appropriate management of these fractures depends on careful scrutiny of radiographs and a thorough clinical history to exclude the diagnosis of a periprosthetic infection. In a periprosthetic tibial fracture with a stable, well-aligned tibial component and well-aligned mechanical tibial axis, the fracture can be successfully managed with closed reduction and cast immobilization; meticulous follow-up is essential to ensure that the alignment is maintained. Major fracture displacement, tibial component instability, and tibial component malalignment are all indications for surgical intervention. The ideal surgical intervention depends on the fracture characteristics and the stability and alignment of the tibial component.

Acute exposure of white-tailed deer cortical bone to Staphylococcus aureus did not result in reduced bone stiffness

Staphylococcus aureus (S. aureus) is the main source of osteomyelitis in adults. The end-result of untreated osteomyelitis is bone necrosis and distraction of bone structure. While bone tissue can heal and remodel its structure to ameliorate its mechanical properties, so far no study has tested the mechanical properties of cortical bone tissue exposed to S. aureus. With the increase usage of bone banks as a source of bone graft supply, it is important to screen for any possible pathology that may affect the bone graft success to function normally in the receiving patient. This study tested the effect of acute exposure to S. aureus on cortical bone stiffness. We have postulated that the incubation of cortical bone with S. aureus for 48 h will result in a significant decrease in bone stiffness. Sixty-five bone cubes (2 × 2 × 2 mm) were prepared from the cranial and caudal aspects of four white-tailed deer mid-diaphysis humeri. First, all bone samples were tested to determine their stiffness in the three principle orientations (axial, radial and transverse). Next, bone samples were incubated for 48 h with S. aureus (32 cubes, experimental group) or with sterile distilled water (33 cubes, control group). Finally, all cubes were mechanically tested again and each stiffness value was compared to the original value obtained from the same cube. Our results revealed that overall, acute exposure to S. aureus did not significantly decrease bone stiffness and thus our working hypothesis could not be supported. Therefore, our findings support the current tissue collection screening methods employed by bone-graft banks.

Equivalent mortality and complication rates following periprosthetic distal femur fractures managed with either lateral locked plating or a distal femoral replacement

INTRODUCTION

Management of distal femur fractures above total knee arthroplasty (TKA) remains challenging. Two common surgical options are locked lateral plating (LLP) and distal femoral arthroplasty (DFR). Unfortunately, approximately 30-50% of patients may die within one year of injury, require further surgery, or not regain prior mobility performance. We compared 87 LLP to 53 DFR patients - to our knowledge the largest comparative study - focusing on 90- and 365-day mortality, mobility maintenance, and further surgery.

METHODS

We performed a retrospective review of patients at least 55 years old who sustained femur fractures near a primary TKA (essentially OTA-33 or Su types 1, 2, or 3) from 2000 to 2015 assigning cohort based on treatment: LLP or DFR. We excluded patients having prior care for the injury, whose surgery was not for fracture (e.g. loosening), or having other surgical intervention (e.g. intramedullary nail).

RESULTS

Results Cohorts were similar based on body mass index and age adjusted Charlson Comorbidity Index (aaCCI). LLP was more common than DFR for fractures above and at the level of the implant, but similar for fractures within the implant for patients with aaCCI ≥ 5. LLP and DFR had similar mortality at 90 days (9% vs 4%) and 365 days (22% vs 10%), need for additional surgery (9% vs 3%), and survivors maintaining ambulation (77% vs 81%). Patients whose surgery occurred 3 or more days after presentation had similar mortality risk to those whose surgery was before 3days. The mean age of one year survivors was 77 whereas for patients who died it was 85. Neither surgical choice nor aaCCI was associated with increased risk in time to surgery.

CONCLUSIONS

Fracture location, remaining bone stock, and patient's prior mobility and current comorbidities must guide treatment. Our study suggests that 90- and 365-day mortality, final mobility, and re-operation rate are not statistically different with LLP vs DFR management.

Circular hexapod external fixation for periprosthetic tibial fracture

A poor soft tissue envelope often accompanies periprosthetic tibia fracture around a well-fixed total knee arthroplasty and the tibial stem leaves little room for screw fixation. This article describes the practicability and effectiveness of a novel surgical technique using circular hexapod external fixation, in patients with this clinical scenario. It was applied for fixation of periprosthetic tibia fracture in 2 patients. Contact between the external fixation pins and the prosthesis was avoided. Using a web-based software program, a gradual reduction in all planes was achieved. Adequate fixation, stability, reduction, and quick healing were obtained in the 2 cases, with minimal complications. The patients returned to their activity level a few months after external fixation removal.

Periprosthetic fractures: epidemiology and current treatment

Periprosthetic fractures are becoming increasingly frequent due to aging population and growing number of total joint replacements involving joints different from hip and knee, such as shoulder and elbow. The treatment of these fractures still represents one of the major challenges for the orthopedic surgeon. Despite all efforts to understand and treat these patients, high rate of failure and mortality are still reported. In this review, the epidemiology of periprosthetic fractures, risk factors and results of surgical treatment are disclosed. Moreover, we propose a treatment algorithm based on the findings of the New Unified Classification System.

Periprosthetic fractures of the distal femur after total knee arthroplasty : Plate versus nail fixation

The incidence of periprosthetic fractures about a TKA is increasing. Traditionally, these fractures are classified by their location and prosthesis integrity. In the setting of a supracondyar fracture about a well-fixed prosthesis, both plate and nail fixation of the fracture present themselves as options, each with unique benefits and pitfalls. Through review and discussion of the literature, we aim to describe some of the patient, fracture, and implant related factors that should be considered when planning fixation of periprosthetic fractures about a TKA. Additionally, we present several technical pearls that may be useful in the successful treatment of these difficult injuries.

LEVEL OF EVIDENCE

4.

Successful outcome with minimally invasive plate osteosynthesis for periprosthetic tibial fracture after total knee arthroplasty

INTRODUCTION

The incidence of periprosthetic fractures after total knee arthroplasty (TKA) is increasing, and treatment is becoming more necessary. In periprosthetic tibial fractures, the stem of the tibial component largely occupies the medullary canal of the proximal tibia, which limits the selection of implants. The purpose of this study was to evaluate the effectiveness of the minimally invasive plate osteosynthesis (MIPO) technique with locking plates for periprosthetic tibial fractures after TKA.

MATERIALS AND METHODS

Sixteen patients with periprosthetic tibial fracture after TKA were included. There were 6 type II and 10 type III fractures according to the Felix classification. Ten patients had fractures in the proximal metaphysis, and 6 in the diaphysis. MIPO using locking plates was performed on the medial side in 4 cases, the lateral side in 2 cases, and both in 10 cases. Radiographic results included time to union, alignment, and malunion. Clinical results included range of motion (ROM), functional activity data, Knee Society scores, and complications.

RESULTS

Fourteen of 16 fractures achieved union at 17.1 weeks (range, 14-24) postoperatively. There were 2 failures that required a secondary procedure. Except one for 1 case with varus malunion, all had acceptable alignment. Mean ROM at the final follow-up was 108.8° (range, 15-135°), and 15 patients recovered pre-injury knee joint activity. Mean knee and function scores were 88.9 (range, 77-100) and 83.3 (range, 60-100), respectively. Knees with fewer than 8 cortices giving purchase to screws in the proximal segment showed higher failure rates (P=0.025).

DISCUSSION

MIPO with locking plates can achieve satisfactory results for periprosthetic tibial fractures after TKA. Rigid fixation of the proximal segment may be necessary for successful outcome.

LEVEL OF EVIDENCE

IV.

Bilateral distal femoral fracture after total knee arthroplasty

The number of total knee arthroplasties has increased exponentially and their indications have been expanded. This procedure presents challenging complications for orthopedic surgeons that are potentially catastrophic for patients. Here, a rare case of simultaneous bilateral periprosthetic fracture of the knee is reported, with discussion of the causal factors, possible management and prophylaxis.

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

This study was designed to itemize and analyze the classification of fracture types and their corresponding outcomes in an attempt to provide a better understanding of the current treatment methods. Two PubMed searches were performed using the words "periprosthetic distal femur fracture" and "periprosthetic supracondylar femur fracture" in studies that were published in the previous 10 years (2004-2014). Data from 41 articlesthat met the general inclusion criteria, were collected and categorized into fracture type and treatment method groupings. Healing outcome and complications were the two parameters used to analyze the data. Treatment techniques were grouped in the following categories: locking plate, non-locking plate, intramedullary nail/rod, screw, blade plate, cerclage wires, allograft, external fixation, revision arthroplasty, non-operative, and other. Classification systems by Lewis and Rorabeck, the Association for Osteosynthesis/Orthopedic Trauma Association (AO/OTA), Su et al., Neer et al., Kim et al., Backstein et al., and the Société Française de Chirurgie Orthopédique et Traumatologique were reported. In total 448 fractures were identified, of which Rorabeck type II was the most common fracture studied. The two most successful treatment options for periprosthetic distal femur fractures were locking plate (87%) and intramedullary nail/rod (84%). The most frequent complications associated with periprosthetic distal femur fractures included non/mal/delayed union and the need for revision. Locking plates used to treat Rorabeck type II fractures had a complication rate of 35% and those treated with intramedullary nailing had a higher complication rate of 53%. In conclusion, the most frequent type of periprosthetic distal femur fracture after total knee arthroplasty was Rorabeck type II. The most common treatments for these types of fractures are locked plating and intramedullary nailing, with similar healing rates of 87% and 84%, respectively. However, the complication rate for locked plating was lower than for intramedullary nailing.

Preliminary testing of a novel bilateral plating technique for treating periprosthetic fractures of the distal femur

BACKGROUND

Current stabilization methods for periprosthetic fractures of the distal femur are inadequate in achieving fracture fixation, with complication rates as high as 29%. A major contributor to poor outcomes is that these methods rely only on screw purchase in the bone to maintain fracture reduction. We designed, manufactured and evaluated a novel plating method that utilizes the femoral prosthesis to enhance stability for treatment of distal femoral periprosthetic fractures.

METHODS

Medial and lateral plates were designed and manufactured based on geometry of a synthetic femur and femoral prosthesis. The two plates were linked via a compression screw and a small tab on each plate that inserted into pre-existing slots on the prosthesis. Mechanical tests (500N compression or 250N anterior directed cantilever bending), were performed on synthetic femurs with simple transverse fractures (3mm gap) just superior to the distal femoral prosthesis that were stabilized using either the prototype plates or a single lateral plate. Translational movements of the fracture site during loading were measured using 3D motion tracking.

FINDINGS

With the single lateral plate, the distal fragment experienced a resultant displacement of 0.40mm under cantilever bending and 0.61mm under compression (13% and 20% respectively of fracture gap width). With the bilateral plates, fracture gap motion was significantly reduced to 0.13mm under bending and compression (4.3% of the fracture gap).

INTERPRETATION

Our results indicate that a bilateral plating method is capable of improving stabilization of periprosthetic fractures compared to the traditional lateral plating technique.

Locked plate versus retrograde intramedullary nail for periprosthetic femur fractures above total knee arthroplasty: a meta-analysis

PURPOSE

Locked plate (LP) and retrograde intramedullary nail (RIN) are the most commonly used treatment options for periprosthetic femur fracture above total knee arthroplasty (TKA). Controversy still exists regarding which is better. Therefore we performed a meta-analysis to compare their clinical results.

METHODS

A comprehensive search was conducted through PubMed, EMBase and the Cochrane Collaboration Library. Six comparative studies (265 patients) were included for the meta-analysis.

RESULTS

No statistically significant differences were found between the LP group and RIN group in terms of six month union rate (OR, 1.19; 95 % CI, 0.52-2.69; P = 0.68), union time (WMD, 0.22; 95 % CI, -0.41 to 0.84; P = 0.50), operation time (WMD, 0.54; 95 % CI, -13.09 to 14.17; P = 0.94) or complication rate (OR, 0.79; 95 % CI, 0.22-2.91; P = 0.73). The LP fixation may have a relatively higher re-operation rate (OR, 5.17; 95 % CI, 1.02-26.27; P = 0.05) compared with RIN. The mean union time was 4.0 months in the LP group and 3.7 months in the RIN group.

CONCLUSION

This meta-analysis found no statistically significant difference in six month union rate, union time, operation time and complication rate between the LP group and RIN group. The RIN fixation may have a potential of lower re-operation rate compared with LP. The mean union time was 4.0 months in the LP group and 3.7 months in the RIN group.

Plate failure following plate osteosynthesis in periprosthetic femoral fractures

BACKGROUND

Increasing numbers of total knee and hip arthroplasties result in a growing number of periprosthetic femoral fractures (PPFF). PPFF with a stable stem component are treated commonly with plate osteosynthesis. Therefore plate failure is seen as a major complication. The aim of this retrospective study was to investigate the patients' outcome after plate failure.

METHODS

The database of a Level 1 trauma center was searched for all patients treated for a PPFF with plate osteosynthesis. Patients with plate failure were investigated specifically. Standard demographic data, details on initial arthroplasty, trauma, and treatment were recorded for all patients. All fractures were classified and their outcome reviewed.

RESULTS

Seven (8.8%) out of 80 patients treated with plate osteosynthesis following PPFF met our inclusion criterion being plate failure. All these patients were female, with an average age at primary surgery of 74 ± 13 years and a mean follow-up of 885 days (range, 264-2549). Four patients suffered a PPFF after total hip arthroplasty (THA) (2 Vancouver Type B1 and 2 Type C) and three after total knee arthroplasty (TKA) (Lewis-Rorabeck Type II). Following plate failure, four patients healed uneventfully and three patients experienced complications such as pseudarthrosis, screw loosening, and further plate failure.

CONCLUSION

In patients with poor bone quality, bone graft, bone cement, and bone biologics have to be considered in revision surgery. Furthermore, long-stem revision and tumor prosthesis are an additional solution.

How to interpret postoperative X-rays after total knee arthroplasty

Today, total knee arthroplasty (TKA) is one the most commonly performed surgeries worldwide. The purpose of this article is to review the appearance of normal post-TKA roentgenographs and describe the correct sequence for their interpretation. It is unwise to depend solely on patients' symptoms when diagnosing TKA complications because serial radiographs can foresee failures well before they manifest clinically. Ideal post-TKA radiographs comprise whole lower extremity anteroposterior and lateral views taken under weight bearing conditions along with a skyline view of the patellofemoral joint. Among other things, weight bearing exposes the true alignment, ligamentous laxity and polyethylene wear. On the basis of follow-up of our TKA cases, we have drawn up a protocol for assessing postoperative X-ray films after TKAs. Following the proposed sequence, surgeon can easily decide how to proceed with follow-up and foresee complications. Careful interpretation of postoperative radiographs after TKA is essential to careful monitoring of patients and implant survival.

Periprosthetic supracondylar femoral fractures above total knee arthroplasty: comparison of the locking and non-locking plating methods

PURPOSE

The purpose of this study was to compare the results and complications of periprosthetic supracondylar femoral fracture treatment using locking or non-locking plates.

METHODS

A locking compression plate was used in 14 patients, and a non-locking condylar buttress plate was used in 19 patients. There were no significant differences in the demographic data between the two groups. The primary healing rate and bone union time were compared. The Knee Society knee score and range of motion (ROM) were reviewed. The femorotibial angle and α and γ angles were measured using the Knee Society radiological evaluation method. The clinical and radiographic results, complications, and additional surgeries were compared between the two groups.

RESULTS

Thirteen of 14 locking plating patients and 11 of 19 non-locking plating patients healed without any additional surgeries. There were no differences in the average bone union time, knee score, or ROM between the two groups. The alignment and position of the implants were better without a loss in the reduction angle of >3° in the locking plating group compared with the non-locking plating group. Locking plate fixation reduced the incidence of overall complications, non-union, malunion, loss of reduction, and additional surgeries compared with non-locking plate fixation.

CONCLUSION

Fixation of periprosthetic supracondylar femoral fractures with a locking plate provided satisfactory results with a low risk of complications and additional surgeries compared with fixation with a non-locking plate.

LEVEL OF EVIDENCE

III.

[Retrograde intramedullary nailing for periprosthetic fractures of the distal femur]

OBJECTIVE

Intramedullary stabilization of periprosthetic distal femoral fractures by interlocking nailing. Closed reduction by retrograde nail can be combined with the use of transmedullary support screws (TMS principle of Stedtfeld).

INDICATIONS

Supracondylar fractures above stable knee arthroplasty (Rorabeck types I and II), femoral shaft fractures ipsilateral of stable hip and/or knee arthroplasty, contraindications for antegrade nailing

CONTRAINDICATIONS

Closed box design of femoral implant, intercondylar distance of the femoral component smaller than nail diameter, more than 40° flexion deficit of the knee, inability to place two bicortical distal interlocking screws. Relative contraindication: insufficient overlap with proximal implants

SURGICAL TECHNIQUE

Supine position and knee flexion of approximately 45°. Fluoroscopy should be possible between the knee and hip. Longitudinal skin incision into the pre-existing scar over the patellar tendon which is then split. The nail entry point is located in the intercondylar groove at the deepest point of Blumensaat's line, often predetermined by the femoral arthroplasty component. Reaming is rarely necessary. Transmedullary support screws may correct axial malalignment during nail insertion. Static interlocking in a direction from lateral to medial by the aiming device. Insertion of locking cap.

POSTOPERATIVE MANAGEMENT

Retrograde nailing normally allows full weight bearing. Range of motion does not need to be restricted.

RESULTS

Out of 101 fractures treated between 2000 and 2013 with a Targon RF nail (Aesculap, Tuttlingen, Germany) 10 were periprosthetic, all were classified as Rorabeck type II and of these 6 fractures were metaphyseal and 4 were diaphyseal. In four cases proximal implants were present. The mean operative time for periprosthetic fracture fixation did not significantly differ from that for normal retrograde femoral nailing. There were no postoperative infections, fixation failures or delayed unions. There was one revision for secondary correction of maltorsion.

A Comparison of Mortality following Distal Femoral Fractures and Hip Fractures in an Elderly Population

Introduction. Patients suffering a distal femoral fracture are at a high risk of morbidity and mortality. Currently this cohort is not afforded the same resources as those with hip fractures. This study aims to compare their mortality rates and assess whether surgical intervention improves either outcome or mortality following distal femoral fractures. Methods. Patients over sixty-five admitted with a distal femoral fracture between June 2007 and 2012 were retrospectively identified. Patients mobility was categorised as unaided, walking aid, zimmer frame, or immobile. The 30-day, six-month, and one-year mortality rates were recorded for this group as well as for hip fractures during the same period. Results. 68 patients were included in the study. The mortality rate for all patients with distal femoral fractures was 7% at 30 days, 26% at six months, and 38% at one year, higher than hip fractures during the same period by 8%, 13%, and 18%, respectively. Patients managed surgically had lower mortality rates and higher mobility levels. Conclusion. Patients suffering a distal femoral fracture have a high mortality rate and surgical intervention seems to improve both mobility and mortality.

Periprosthetic fractures around the knee: current concepts and advances in management

Knee replacement is an effective treatment for pain and functional impairment secondary to degenerative joint conditions. The number of knee replacements performed continues to rise. Periprosthetic fractures around total knee arthroplasties are a relatively rare complication but are complex injuries that require the treating surgeon to be familiar with and proficient at arthroplasty and trauma reconstructive techniques. An increase in life expectancy and in the functional demands of elderly patients may lead to an increased incidence of periprosthetic fractures. Supracondylar fractures of the femur are the most common type and this review will focus on the incidence, risk factors, classification, investigation, and treatment options for periprosthetic fractures around total knee arthroplasties.

Locking plate fixation of periprosthetic femur fractures with and without cerclage wires

OBJECTIVE

The number of patients requiring knee and hip arthroplasty has been steadily increasing, and periprosthetic fractures are on the rise. Locking plates are the most common treatment for periprosthetic fractures, but the use of cerclage wires with locking plate fixation has been controversial.

METHODS

Forty-seven patients with periprosthetic femur fractures were reviewed retrospectively. Twenty-four patients received locking plate alone and twenty-three patients were treated with locking plate and cerclage wires. Patients were evaluated for clinical and radiographic signs of union at two, six, twelve, twenty-four, and forty-eight weeks postoperatively.

RESULTS

The average follow-up time in the plate group was 9.4 ± 6.7 months, while it was 6.0 ± 4.2 months in the cerclage wire group. The time to union in the cerclage wire group (3.6 ± 1.0 months) was significantly less than the plate group (4.8 ± 2.6 months). The group with the cerclage wires had a significantly lower revision rate of 0% compared to 20.8%. There was no statistical significance of union rate and complication rate between the two groups.

CONCLUSION

Cerclage wires used with locking plate fixation successfully treats periprosthetic fractures of the femur with faster time to union, less complication, and fewer revisions.

Changes in bone mineral density of the distal femur after total knee arthroplasty: a 7-year DEXA follow-up comparing results between obese and nonobese patients

BACKGROUND AND PURPOSE

Periprosthetic femoral bone mineral density (BMD, g/cm2) decreases after total knee arthroplasty (TKA) as a result of the stress-shielding phenomenon. It is not known whether obesity has an effect on this phenomenon or not. The aim of this study was to assess long-term periprosthetic BMD changes after TKA and compare whether there is a difference between obese and nonobese patients.

METHODS

A total of 69 TKAs in 61 patients were performed, and BMD measurements of the distal femur were followed up to 7 years postoperatively. The patients were divided into two study groups according to their body mass index, and the groups were compared in relation to BMD and functional outcome.

RESULTS

The mean of periprosthetic bone loss during the 7-year follow-up varied from 10.3% to 30.6% depending on the region of interest (p<0.0005). The highest bone-loss rates were detected during the first three postoperative months. A total of 26 patients were categorized as obese with a body mass index value of ≥30 kg/m2. The obese patients' total periprosthetic BMD was higher at both baseline (8.6%) and 7 years after operation (p=0.05) (15.2%).

CONCLUSION

Periprosthetic bone loss around the femoral component continued for up to 7 years postoperatively. The loss of bone density was not associated with any negative clinical outcome in this study, but periprosthetic bone loss was of a smaller quantity in the obese which is probably due to higher weight induced stresses on bone.

Distal femoral replacement for selective periprosthetic fractures above a total knee arthroplasty

BACKGROUND AND AIM

The management of distal femur periprosthetic fractures in the elderly remains a challenge. The aim of this study was to evaluate the results of distal segmental femur replacement as an alternative to fixation in complex distal femoral periprosthetic fractures in elderly patients.

METHODS

Twelve patients were included in this prospective study, with a mean age of 78 years (range 68-90 years); incidentally, all were female. Fractures of the distal femur were classified as per Kim et al.'s classification (Clin Orthop Relat Res 446:167-175, 2006); our series included eight patients with type III and four patients with type II periprosthetic fractures. All 12 patients were treated with segmental distal femur replacement (Zimmer Inc., Warsaw, IN, USA). Nine patients required 90 cm and three patients required 130 cm of distal femur segment with a rotating hinge knee prosthesis.

RESULTS

The mean follow up period was 20 months (range 15-28 months), with no major surgical complications reported. The mean duration of hospital stay following surgery was 12 days (range 7-36 days). All patients were mobilising full weight-bearing by day 3. All patients returned to their prior living arrangements. Ten patients returned to their original domicile, with one patient being discharged to a care home requiring minimal ambulatory assistance. The remaining two patients returned to their care homes.

CONCLUSIONS

WOMAC scores improved from the pre-injury state with a mean of 49.62 to 72.54 post-surgery (p-value of 0.0001). The Knee Society scores, possible only following surgery, had a mean value of 72. The mean VAS pain score was 1.75 (0 = no pain to 10 = worst pain ever felt). The average range of knee flexion was from 4° to 89° (range -5° to 110°). The mean SF-36 physical functioning score was 45.64 [range 40.70-48.90; standard deviation (SD) -2.62] and the mean SF-36 mental functioning score was 52.94 (range 45.8-57.70; SD -3.38).

Outcome and incidence of periprosthetic supracondylar femoral fractures in TKA

BACKGROUND

Periprosthetic supracondylar femoral fractures following total knee arthroplasty (TKA) are infrequent, but is a devastating complication. The purpose of this study was to evaluate the incidence and outcomes of periprosthetic supracondylar femoral fractures following TKA using nonoperative as well as open reduction and internal fixation (ORIF) techniques.

MATERIALS AND METHODS

Between January 2004 and December 2010, we followed 3,920 operated patients of total knee arthroplasty (TKA) and identified 23 patients with periprosthetic supracondylar fractures. A retrospective analysis of the records of these patients was conducted. Details regarding pre fracture status, treatment offered and the present status were also recorded and analyzed. Time from index arthroplasty to periprosthetic fracture ranged from five days to six years. There were 17 women and 6 men and the average age was 68.26 years (range 52-83 years). Of the 23 patients, 20 patients were treated by operative method, whereas only three patients with relatively undisplaced fractures were treated nonoperatively.

RESULTS

The total incidence of periprosthetic fractures in operated cases of TKA was 0.58%. Three patients had infection after surgery. As per radiological assessment, two of three conservatively treated cases had malunion, whereas among 20 cases treated operatively, 16 had primary union with one malunion. Two patients had union after bone grafting, whereas two had nonunion. The average reduction in the knee score after fracture was 20.53%. Twenty one patients were able to achieve limited but independent activity.

CONCLUSIONS

Desirable results for periprosthetic fractures can be obtained if proper and timely intervention is done, taking into account the other comorbid conditions. However, short duration of followup and small number of patients were major limiting factors in this study.

Functional outcome of total knee arthroplasty after periprosthetic distal femoral fracture

A prospective matched cohort study was performed to compare functional outcomes between 28 patients with periprosthetic femoral fractures and 28 with primary total knee arthroplasties (TKA). The mean follow-up was 6.7 years (range, 5-9). Radiographic osteopenia was a predisposing factor, but not notching, body mass index, or preinjury knee scores or motion. At last follow-up, the Knee Society scores, knee motion, Womac, and SF-12 were significantly lower in the fracture group, and were significantly decreased compared to the preinjury status. We found that periprosthetic distal femoral fracture after TKA worsens functional outcomes at the medium term, but arthroplasty complication and survival rates were similar in both groups.

Complications after total knee arthroplasty: periprosthetic fracture after extensor mechanism transplantation

With the increase in total knee replacements in Brazil there is also an increase in the number of complications. The authors report a case in which 3 serious complications happened after a total knee replacement and the treatment was based on the literature, but individualized to the patient in some important points. The outcome was considered very good.

Combining of small fragment screws and large fragment plates for open reduction and internal fixation of periprosthetic humeral fractures

Operative treatment of periprosthetic humeral fractures in elderly patients with osteoporotic bone requires a stable fixations technique. The combination of 3.5 cortical screws with washers in a 4.5 Arbeitsgemeinschaft für Osteosynthesefragen, Limited-contact dynamic compression plate or Locking plate, allows a stable periprosthetic fixation with the small 3.5 screws and 4.5 screws above and below the prosthesis, respectively. This combination is a cost-effective technique to treat periprosthetic humeral fractures.

Periprosthetic fractures around total knee arthroplasty

INTRODUCTION

The number of total knee arthroplasties performed continues to rise annually and it would be expected that complications, which include periprosthetic fractures, will also therefore become more commonplace. This article reviews the current literature regarding this injury and identifies the treatment principles that enable patients to regain optimal function.

METHODS

A comprehensive search of the Pubmed and Embase™ databases was performed to identify relevant articles. Keywords and MeSH (Medical Subject Headings) terms included in the search strategy were 'periprosthetic fracture(s)', 'femur', 'tibia', 'patella(r)', 'complication(s)', 'failure(s)', 'risk(s)', 'prevalence', 'incidence', 'epidemiology' and 'classification(s)'. The search was limited to all articles published in English and reference lists from the original articles were reviewed to identify pertinent articles to include in this review. A total number of 43 studies were identified.

RESULTS

Common treatment aims have been identified when managing patients with a periprosthetic fracture around total knee arthoplasty. The main criterion that determines which option to choose is the degree of remaining bone stock and the amount of fracture displacement.

CONCLUSIONS

Treatment of a periprosthetic fracture around total knee arthroplasty will either be non-operative, osteosynthesis or revision arthroplasty. It is imperative that a suitable option is chosen and based on the published literature, pathways are outlined to aid the surgeon.