Distal Femoral Replacement Research Articles

Survival and functional outcomes after hemiarthroplasty in children with proximal tibial osteosarcoma

BackgroundTreatment options for correcting limb-length discrepancy after limb-salvage reconstruction for proximal tibial osteosarcoma in children have several limitations. Therefore, we aimed to evaluate the feasibility, complications, prognosis, and clinical outcomes of reconstruction using hemiarthroplasty after tumor resection in pediatric patients with proximal tibial osteosarcoma.MethodsWe conducted a comprehensive retrospective analysis of the data of pediatric patients with osteosarcoma of the proximal tibia who underwent surgery between December 2008 and November 2018 at our center. We enrolled 49 consecutive patients who underwent hemiarthroplasty. The cruciate ligaments of all patients were reconstructed using special spacers, and the medial and lateral collateral ligaments of the knee and joint capsule were reconstructed using a mesh. Postoperatively, if the unequal length of both lower limbs exceeded 4 cm or knee instability occurred, a second-stage surgery was performed for limb lengthening and replacing the distal femoral prosthesis. We analyzed the oncological prognosis, complications of hemiarthroplasty, postoperative stability, and postoperative function.ResultsThe follow-up period ranged between 11 and 159 months, with a median of 84 (62, 129) months. The overall 5-year survival rate was 83.2%. Thirty-nine patients survived at the end of the follow-up period with 34 prostheses (87.2%). The overall prosthesis survival rate was 87.4% after 5 years, indicating the long-term benefits of the procedure. Limb length was measured in 28 adult patients. The average limb-length discrepancy was 33 ± 15 mm with a median of 33 mm (21, 47); the femur and tibia caused a discrepancy of 8.5 ± 9.9 mm and 24.8 ± 15.5 mm, respectively. The patients had 30–135° of knee motion, with a mean of 82 ± 24°. The femoral tibial angle was greater on the affected side than on the healthy side, with a mean difference of 4.5°±3.6°. The Musculoskeletal Tumor Society (MSTS) score was 25 ± 3. Five patients underwent second-stage distal femoral prosthesis replacement, with mean MSTS scores of 24 ± 2 and 28 ± 1 before and after second-stage surgery, respectively.ConclusionsHemiarthroplasty in children reduces limb-length discrepancy in adulthood by rebuilding cruciate ligaments, lateral collateral ligaments, and the joint capsule, thereby improving knee stability.

Fix or Replace? Comparable Outcomes with Internal Fixation and Distal Femoral Replacement for Periprosthetic Fractures above Total Knee Arthroplasty

IntroductionThe optimal treatment for periprosthetic fracture (PPfx) around total knee arthroplasty (TKA) remains a topic of debate. Due to its low incidence, comparative studies analyzing arthroplasty and fixation are lacking in the literature. The purpose of this study was to compare the outcomes of distal femoral replacement (DFR) and open reduction and internal fixation (ORIF) for distal femur PPfx. MethodsWe reviewed a consecutive series of 99 patients who underwent DFR (n = 54) or ORIF (n = 45) for distal femur PPfx. The indications for DFR were reviewed. Fractures were classified based on their relation to the implant using the Su classification. The primary outcome was re-revision, while secondary endpoints included inpatient complications, mortality within the first year, and mechanical complications such as loosening and non-union. ResultsType 2 fractures were the most prevalent type in both groups (DFR 37 versus ORIF 48.9%), while Type 1 fractures were more commonly treated with ORIF (35.6 versus 16.7%) and Type 3 with DFR (46.3 versus 15.6%) (P = 0.003). The preferred techniques in the ORIF group were plate osteosynthesis (66.7%) and retrograde nailing (31.1%). At a mean follow-up of 4.2 years (range, 1 to 14.1), DFR and ORIF did not demonstrate any difference in revision rates (13 versus 24.4%, P = 0.140) or mortality (3.7 versus 4.4%, P = 0.887). However, more mechanical complications were noted in the ORIF group (22.2 versus 7.4%, P = 0.035). ConclusionBoth distal femoral replacement and open reduction and internal fixation have comparable revision rates, complications, and clinical outcomes when used in supracondylar periprosthetic distal femur fractures. Longer-term studies are needed to assess DFR survivorship as well as outcomes of newer trauma techniques such as nail-plate combinations.

Distal femur fractures in elderly treated with internal fixation or distal femoral replacement - retrospective cohort study on 75 patients assessing functional outcomes, reoperations, and mortality.

This cohort study aimed to describe the functional outcomes, complications, and mortality of patients over 65 with acute distal femur fractures treated with open reduction and internal fixation (ORIF) or distal femoral replacement (DFR). We retrospectively analyzed all patients older than 65, operated consecutively for a distal femur fracture treated with ORIF or DFR. We included 75 patients (9 33A, 5 33B, and 61 33C AO/OTA fractures), 55 treated with ORIF, and 20 with DFR. We used Parker's mobility index (PMI) to assess functional outcomes at 1, 3, and 12months and study closure. We analyzed complications, reoperations, and mortality at 30days, one year, and at the end of the study. The PMI was significantly higher in the DFR group at months 1 (p = 0.023) and 3 (p = 0.032). We found no significant differences between cohorts at one year and the end of follow-up. Postoperative complications were significantly more frequent in the ORIF group (38.10% vs. 10%, p = 0.022). Reoperations were similar in both cohorts (p = 0.98). Mortality at one month was 4% and 20% at one year, and at the end of follow-up, there were no significant differences between groups. The outcomes of this study suggest that DFR offers a faster functional recovery with lower complication rates than those treated with ORIF. Additionally, both options have similar reoperation and mortality rates. Appropriately designed studies are needed to define the best treatment strategy for this type of patient.

The Role of a New Hinged Total Knee Arthroplasty System for Use in a Variety of Complex Knee Scenarios: A Case Series.

Hinged knee arthroplasties are commonly used in scenarios where there are major ligament deficiencies or bone loss around the knee. They are applicable in native knees with major deformities and during revisions. They can also be used as a salvage procedure after distal femoral resection. The new modular hinged device system, namely the Triathlon Hinge Knee (THK) System (Stryker, Mahwah, New Jersey), reflects the advancements of third-generation design and enhances surgical flexibility by allowing streamlined integration with the Triathlon Total Stabilized (TS) System (Stryker, Mahwah, New Jersey) and the Global Modular Replacement System (GMRS, Stryker, Mahwah, New Jersey). Additionally, the Triathlon Revision Tibial Baseplate (Stryker, Mahwah, New Jersey) has been launched as part of THK and is compatible with the Modular Rotating Hinge (MRH , Stryker, Mahwah, New Jersey) femur, which allows the Revision Baseplate to replace the existing tibial component while leaving the existing MRH Femoral Component in place. The Triathlon Revision Tibial Baseplate enables orthopaedic surgeons to use constrained or hinged prostheses, including both distal and total femoral replacement options, without changing the Tibial Baseplate. This is because the TS, MRH, THK, and GMRS femurs are compatible with the new Triathlon Revision Tibial Baseplate. Additionally, the system can be augmented with metaphyseal cone constructs to help provide a stable foundation for reconstruction. This report explores the application of a new modular hinged device system in various scenarios, starting with (1) complex primary hinged knee arthroplasty, followed by revision hinged knee arthroplasty cases including (2) failed TKA with medial collateral ligament (MCL) dysfunction, (3) severe arthrofibrosis post-TKA, (4) revisions for prosthetic joint infection, (5) extensor mechanism deficiency, and (6) arthrofibrosis with extensor mechanism disruption, concluding with a case of (7) distal femoral arthroplasty for periprosthetic fracture post-failed TKA.

Staged Management for Distal Femur Fractures: Impacts on Reoperation, Stiffness, and Overall Outcomes.

To evaluate the outcomes of staged management with external fixation (ex-fix) prior to definitive fixation of distal femur fractures. Design: Retrospective cohort. Single Level I Trauma Center. Adults treated operatively between 2004 and 2019 for distal femur fractures (OTA/AO 33A/33C) were identified using Current Procedural Terminology codes. Excluded cases were those with screw only fixation, acute distal femur replacement, 33B fracture pattern, no radiographs available, or did not have 6-months of follow-up. Postoperative complication rates including surgical site infection [SSI], reoperation to promote bone healing, final knee arc of motion <90 degrees, heterotopic ossification formation, and reoperation for stiffness were compared between patients treated with ex-fix prior to definitive fixation and those not requiring ex-fix. A total of 407 patients were included with a mean follow-up of 27 months (median [IQR] of 12 [7,33] months), (range 6-192 months). Most patients were male (52%) with an average age of 48 [Range: 18-92] years. Ex-fix was utilized in 150 (37%) cases and 257 (63%) cases underwent primary definitive fixation. There was no difference in SSI rates (p=0.12), final knee arc of motion <90 degrees (p=0.51), and reoperation for stiffness (p=0.41) between the ex-fix and no ex-fix groups. The 150 patients requiring ex-fix spent an average of 4.2 days (SD 3.3) in the ex-fix before definitive fixation. These patients were further analyzed by comparing the duration of time spent in ex-fix, <4 days (n=82) and ≥4 days (n=68). Despite longer time spent in ex-fix prior to definitive fixation, there was again no significant difference in any of the complication and reoperation rates when comparing the two groups, including final knee arc of motion <90 degrees (p=0.63), reoperation for stiffness (p=1.00), and SSI (p=0.79). Ex-fix of distal femur fractures as a means of temporary stabilization prior to definitive ORIF does not increase the risk of complications such as SSI, final knee arc of motion <90 degrees, or reoperations for bone healing or stiffness when compared to single stage ORIF of distal femur fractures. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Total Femur Replacement as a Salvage Procedure for Failed Distal Femur Megaprosthesis: A Case Report and Literature Reviews

Abstract Total femoral replacement (TFR) is not a common surgery and most indications are for oncological pathologies. However, there are few instances where non-oncological indications might necessitate TFR; this may be a salvage surgery for failed previous hip and/or knee surgeries with consequent significant femur bone loss. We present a 59-year-old obese woman with right thigh pain and difficulty with walking of 5 years duration. She had undergone bilateral total knee replacement 10 years earlier on account of severe knee osteoarthritis. She had a fall 3 years prior to presentation and sustained a periprosthetic fracture around the right knee which was managed with a fixed angle blade plate and screws. This was complicated by implant breakage and non-union. She subsequently had implant removal and a right distal femur replacement (DFR) surgery 2 years prior to presentation. A year after the DFR surgery, she began to experience “start-up” pain, instability around the knee and difficulty with walking without support. A clinical and radiologic diagnosis of aseptic loosening of the distal femur megaprosthesis was made and she was offered a revision DFR surgery which also failed due to poor cementing technique, bone loss at the proximal femur, and severe osteoporosis. Patient ended up with a right total femur replacement to salvage the limb. She had improved Lower Extremity Functional Score of 27 after 12-month follow-up. TFR is a viable salvage procedure for severely compromised femur and/or significant bone loss from multiple non-oncological surgeries of the femur.

OUTCOMES OF DISTAL FEMUR FRACTURE IN THE ELDERLY TREATED WITH EITHER SINGLE PLATE OR DUAL PLATING OR NAIL-PLATE COMBINATION: A RETROSPECTIVE ANALYSIS FROM A SINGLE CENTRE

IntroductionDistal femur fracture fixation in elderly presents significant challenges due to osteoporosis and associated comorbidities. There has been an evolution in the management of these fractures with a description of various surgical techniques and fixation methods; however, currently, there is no consensus on the standard of care. Non-union rates of up to 19% and mortality rates of up to 26 % at one year have been reported in the literature. Delay in surgery and delay in mobilisation post-operatively have been identified as two main factors for high rate of mortality. As biomechanical studies have proved better stability with dual plating or nail-plate combination, a trend has been shifting for past few years towards rigid fixation to allow early mobilisation. Our study aims to compare outcomes of distal femur fractures managed with either single plate (SP), dual plating (DP) or nail-plate construct (NP).MethodsA retrospective review of patients aged above 65 years with distal femur fractures (both native and peri-prosthetic) who underwent surgical management between June 2020 and May 2023 was conducted. Patients were divided into three groups based on mode of fixation - single plate or dual plating or nail-plate construct. AO/OTA classification was used for non-periprosthetic, and Unified classification system (UCS) was used for periprosthetic fractures. Data on patient demographics, fracture characteristics, surgical details, postoperative complications, re-operation rate, radiological outcomes and mortality rate were evaluated. Primary objective was to compare re-operation rate and mortality rate between 3 groups at 30 days, 6 months and at 1 year.ResultsA cohort of 32 patients with distal femur fractures were included in this study. 91% were females and mean age was 80.97 (range 68–97). 18 (53%) were non-periprosthetic fracture and 14 (47%) were periprosthetic fractures.18 patients underwent single plate fixation (AO/OTA 33A – 8, 33B/C – 2, UCS V3B – 5, V3C – 3),10 patients had dual plate fixation (AO/OTA 33A – 1, 33B/C – 4, UCS V3B – 3, V3C – 2) and 4 patients underwent nail-plate combination fixation (AO/OTA 33A – 4). 70.5% patients had surgery within 36 hours of admission and 90% within 48 hours. Analysis showed no re-operation at 30 days, 6 months in all 3 groups. At 1 year one patient had re-operation in dual-plating periprosthetic group (Distal femur replacement done for failed fixation). Three patients (16%) in single plate group had re-operation at 2 years (2 for peri-implant fracture and 1 for infection). None of the patients treated with Nail-plate combination had re-operation. Mortality rate at 30 days was 0% in among all the 3 groups. At 6 months, it was 16% in single plate group and 0% in DP and NP groups at 6 months and at 1 year mortality rate was 27% in SP group, 10% in DP and 0% in NP group. Combined mortality rate was 0% at 30 days, 9% at 6 months and 18.7% at one year.ConclusionOur analysis provides insights into fixation methods of distal femur fractures in elderly patients. We conclude that a lower re-operation rate and mortality rate can be achieved with early surgery and rigid fixation with either dual plating or nail-plate construct to allow early mobilisation. Further prospective studies are warranted to confirm these findings and guide the selection of optimal surgical strategies for these challenging fractures.

Fixation Vs Arthroplasty for Management of Geriatric Distal Femur Fractures

Abstract Background Distal femur fractures are considered challenging to manage, particularly in geriatric patients. Double plating (DP) is a technique that helps with earlier rehabilitation and return to pre-injury level of activity. Distal femoral replacement (DFR) is an alternative technique in the management of these fractures that may help to solve problems like associated knee osteoarthritis, osteoporosis, and severely comminuted condyles. The current study compares the functional and radiological outcomes of DFR and DP in the management of these fracture among geriatric patients. Methods This randomized, comparative, interventional study was performed at a university hospital. A total of 30 patients who underwent DFR or DP after distal femur fractures (AO/OTA 33 A3, 33 C) were analyzed. The primary outcome was Knee Society Score (KSS), whereas secondary outcomes included postoperative complications rate, knee range of motion (ROM), reoperation rate, and operative time. Results No significant difference was observed between DFR and DP except for the knee component of the KSS at 12-month interval (p = 0.03), and knee ROM at 12-month interval (p = 0.001), both of which were in favor of DP. No significant difference in postoperative complications (p = 0.06), reoperation rate (p = 1.00), or operative time (p = 0.06) were noted. Conclusion DFR and DP had comparable functional (KSS) and radiological outcomes with no significant difference in postoperative complications, reoperation rate, or operative time.

The Patient Acceptable Symptom State (PASS) after proximal and distal femoral replacement

IntroductionFemoral megaprostheses are used for bone reconstruction surgery in patients with local tumors or who require multiple revisions. Patient reported outcome measures (PROMs) provide a subjective result and, like patient satisfaction, have become an integral part of the outcomes in orthopedics. However, the threshold of satisfaction (PASS: Patient Acceptable Symptom State) has not yet been defined in a French population after this type of arthroplasty. This led us to carry out a retrospective study on a population of patients who received a femoral reconstruction megaprosthesis in order to 1) define the PASS for the Harris Hip Score (HHS), Knee Society Score (KSS) and the Musculoskeletal Tumor Society score (MSTS), 2) study the complications. HypothesisThe PASS threshold for proximal femur and distal femur reconstruction prothesis for the HHS and the KSS, respectively, will be lower than the threshold for these same scores for primary arthroplasty. Materials and methodsForty-four patients who were operated on between 2009 and 2020 were included: 23 received a proximal femur prosthesis and 21 received a distal femur prosthesis. The PASS threshold was defined using an anchoring strategy by analyzing ROC curves for the HSS for the proximal femur, KSS for the distal femur and the MSTS for all the prostheses. Complications were classified according to Henderson. ResultsThe mean follow-up was 4.5 ± 3.6 (1–12.5) years. The PASS threshold was 47.5 (area under curve (AUC) 0.71 (0.45–0.97)) for the HHS, 69.5 (AUC 0.97 (0.92–1.0)) for the KSS knee and 62.5 (AUC 0.81 (0.61–0.99)) for the KSS function. Thirteen patients (29%) had complications, nine of whom required another surgery (20%). The most frequent were Henderson type 1 (soft tissue lesions, n = 5/44 [11%]) and type 2 (loosening, n = 5/44 [11%]) There was no relationship between satisfaction and postoperative complications (p = 0.071). DiscussionMost of the patients who undergo femoral resection and reconstruction (59%) are satisfied with their function, albeit reduced, despite a high complication rate (29%). Our hypothesis is confirmed for the PASS threshold for the HHS (47.5 versus 93) and the KSS knee and function (69.5 and 62.5 versus 85.5 and 72.5). Level of evidenceIV; retrospective observational single-center study.

Outcomes of distal femoral replacement versus internal fixation for metastatic bone diseases of the distal femur

BackgroundIn clinical practice, internal fixation (IF) is a commonly utilized technique for metastatic bone disease (MBD) to the distal femur. Additionally, distal femoral reconstruction (DFR) has shown to be an effective surgical technique for primary tumors and MBD in the distal femur. The existing body of research comparing these methods has not focused on MBD or pathological fractures and thus does not guide surgical approach in the case of distal femoral MBD. MethodsA multi-institutional retrospective review of musculoskeletal oncology patients treated surgically with IF (n = 29) or DFR (n = 34) for distal femoral MBD between 2005 and 2023. Overall survival, revision risk, and functional status were assessed. Results5-year patient overall survival was 47.9 % (CI, 29.5–77.6 %) and 46.6 % (CI, 31.5–68.8 %), for DFR and IF, respectively (p = 0.91). After competing risk analysis, the 5-year risk of implant revision for DFR was 18 % (95 % CI: 5.1–37 %) and 11 % for IF (95 % CI: 2.4–28 %) (p = 0.3). DFR had longer operative times (p = 0.002), higher blood loss (p < 0.001), and greater postoperative (p = 0.006) complications than IF. In addition, patients undergoing DFR had more distal lesions than patients who received IF (p = 0.003). ConclusionDespite similar overall survival and revision rates, IF may be preferable for patients due to its shorter operative time and lower rates of complication than DFR. However, specific anatomic location in the distal femur must be considered prior to deciding which procedure is optimal.

Patients Regularly Return to Medium- and Low-Impact Types of Sporting Activities Following Distal Femoral or Proximal Tibial Replacement After Resection of a Primary Bone Sarcoma

BackgroundLittle is known about the resumption of sporting activities following megaprosthetic reconstruction of the distal femur and proximal tibia after resection of a bone sarcoma. Thus, the aims of our study were: (1) to assess the functional outcome; (2) to evaluate pre- and post-operatively performed sporting activities; and (3) to identify potential beneficial and limiting factors. MethodsBetween 1993 and 2015, a total of 230 patients underwent distal femoral replacement (DFR), and 96 patients underwent proximal tibial replacement (PTR). The exclusion criteria were death, amputation, living overseas, and a congenital disability. Functional outcome and sporting activities were assessed using the Musculoskeletal Tumor Society Score (MSTS), Toronto Extremity Salvage Score (TESS), Forgotten Joint Score (FJS), subjective knee value (SKV), the Tegner activity score (TS), and the modified weighted activity score (WAS). ResultsThere were 93 patients who had a median follow-up of 182 months (interquartile range (IQR) 130 to 260) after DFR with the following median scores: MSTS 18 (IQR 12 to 23), TESS 75% (IQR 60 to 84), FJS 25 (IQR 8 to 40), SKV 53% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 0 to 8). There were 42 patients who had a median follow-up of 193 months (IQR 137 to 244) after PTR had the following median scores: MSTS 17 (IQR 15 to 22), TESS 78% (IQR 68 to 88), FJS 32 (IQR 20 to 46), SKV 60% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 1 to 10). Postoperatively, 61% of DFR and 76% of PTR patients participated in at least one sporting activity. ConclusionsThe functional outcome is overall good with a regular resumption of sporting activities. Patients’ age at surgery and higher preoperative sporting levels were associated with better functional outcomes and higher postoperative sporting activity.

3D-Printed Metaphyseal Cones in Revision Total Knee Arthroplasties: Excellent Survivorship of 740 Cones at 5 Years.

Porous metaphyseal cones are frequently utilized during revision total knee arthroplasty (TKA) procedures. The purpose of the present study was to evaluate 3D-printed metaphyseal cones used for revision TKA, with specific emphasis on implant survivorship, radiographic appearance, and clinical outcomes after short-term follow-up. We identified 740 cones (498 tibial, 242 femoral) that had been inserted during 533 revision TKA procedures that had been performed at a single tertiary care academic institution. Aseptic loosening (n = 199), periprosthetic joint infection (PJI) (n = 183), and instability (n = 84) were the most common reasons for the index revision. Type-2B or 3 bone loss was present in 67% of the knees. The mean age was 66 years, the mean body mass index was 34 kg/m2, and 55% of the patients were female. Serial radiographs were reviewed. The mean duration of follow-up was 4 years. The 5-year cumulative incidence of cone revision for aseptic loosening was 1% (95% confidence interval [CI], 0% to 3%). The 5-year cumulative incidence of any cone revision or removal was 6% (95% CI, 4% to 9%). In total, 37 cones (19 femoral, 18 tibial) were revised, with PJI (n = 23; 14 recurrent), periprosthetic femoral fracture (n = 3), arthrofibrosis (n = 3), and aseptic loosening of the femoral component and femoral cone (n = 3) as the most common reasons for cone revision. The 5-year cumulative incidence of any TKA re-revision was 14% (95% CI, 11% to 18%). There were a total of 67 re-revisions, with PJI (n = 38), persistent drainage (n = 6), and extensor mechanism disruption (n = 3) being the most common reasons. Radiographically, 2 unrevised femoral cones and 1 unrevised tibial cone appeared to be possibly loose; all 3 cones were in knees with distal femoral replacements or hinged constructs. This large series showed that 3D-printed titanium metaphyseal cones were very durable at short-term follow-up, with a 5-year cumulative incidence of cone revision for aseptic loosening of 1%. PJI was the most common reason for cone revision and any revision. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

High Rate of Unplanned Reoperation for Interprosthetic Femur Fractures After Total Hip and Knee Arthroplasty

BackgroundInterprosthetic femur fractures (IPFFs) are a rare, but devastating complication following total joint arthroplasty. There is limited evidence to help guide their management. The purpose of this study was to describe the features, treatment, and outcomes of surgically managed IPFFs. MethodsWe retrospectively identified 75 patients who had 76 IPFFs. The mean age at the time of IPFF was 75 years (range, 29 to 94), and 78% were women. The mean body mass index was 30 (range, 19 to 51), and the mean follow-up was 3 years (range, 0 to 14). There were 16 Vancouver B1 fractures, 28 Vancouver B2 fractures, 2 Vancouver B3 fractures, and 30 Vancouver C fractures. All B1 fractures underwent open reduction internal fixation (ORIF). All Vancouver B2 and B3 fractures underwent revision arthroplasty, including 1 proximal femur replacement and 1 total femur replacement. Vancouver C fractures were treated with ORIF (n = 20), distal femoral replacement (n = 9), and in 1 case, total femur replacement (n = 1). Kaplan-Meier survivorship was used to calculate 2-year survival free from all-cause reoperation and periprosthetic joint infection (PJI). ResultsThe 2-year survivorship-free rate from reoperation was 71%. There were 18 reoperations following initial surgical management of the IPFF, including 9 for infection, 3 for refracture, 3 for nonunion, 2 for hardware failure, and 1 for instability. An initial IPFF involving a stemmed femoral total knee arthroplasty component was associated with increased risk for reoperation (P = .007) and PJI (P = .044). There was no difference in survivorship free of reoperation between IPFFs managed with ORIF or revision arthroplasty (P = .72). ConclusionsAn IPFF is a devastating complication following total joint arthroplasty with high reoperation rates, most commonly secondary to PJI. Those IPFFs that occurred between 2 stemmed components were at the highest risk for reoperation.

Distal femoral replacement for the treatment of periprosthetic distal femoral fractures around a total knee arthroplasty: a meta-analysis.

Periprosthetic fracture is a rare complication of arthroplasty but can have devastating consequences for the patient and presents a complex surgical challenge. Locking compression plate and retrograde intramedullary nail are both widely accepted surgical fixation techniques for distal femoral periprosthetic fractures around a total knee arthroplasty. Although there is still a need for further high-quality research into both techniques, there is even less literature concerning the use of distal femoral replacement to treat distal femoral periprosthetic fractures. Interest has been piqued in distal femoral replacements for the treatment of distal femoral periprosthetic fractures due to the theoretical advantages of immediate post-operative weight-bearing and lack of dependence on fracture union, but there are still understandably reservations about performing such an extensive and invasive procedure when an accepted alternative is available. This meta-analysis aims to evaluate the current literature to compare the complication rates and return to pre-operative ambulatory status of distal femoral replacement and locking compression plate. A literature search was performed to identify articles related to the management of distal femoral periprosthetic fractures around a total knee arthroplasty in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Methodological quality was assessed using the methodological index for non-randomized studies (MINORS) criteria. Articles were reviewed, and data extracted for analysis. Five articles met the inclusion criteria, reporting on 345 periprosthetic fractures. The overall rates of complications for distal femoral replacement and locking compression plate were: re-operation (6.1% vs 12.1%), infection (3.0% vs 5.3%), mortality (19.7% vs 19.3%), and return to pre-operative ambulatory status (60.9% vs 71.8%) (respectively). This meta-analysis shows no statistically significant difference in the rates of re-operation, infection, mortality or return to pre-operative ambulatory status when comparing distal femoral replacement to locking compression plate.

Dual Plating of Distal Femoral Fractures.

Dual plating of the distal femur is indicated for the treatment of complex intra-articular fractures, supracondylar femoral fractures, low periprosthetic fractures, and nonunions. The aim of this procedure is anatomical alignment of the articular surface, restoration of the articular block, and prevention of varus collapse. Following preoperative planning, the patient is positioned supine with the knee flexed at 30°. The lateral incision is made first, with a mid-lateral incision that is in line with the femoral shaft. If intra-articular work is needed this incision can be extended by curving anteriorly over the lateral femoral condyle. Next, the iliotibial band is transected in line with its fibers. The vastus lateralis fascia is incised and elevated off the septum, working distal to proximal. Care should be taken to maintain hemostasis when encountering femoral artery perforating vessels. Once there is adequate exposure, several reduction aids can be utilized, including a bump under the knee, Schanz pins, Kirschner wires, and reduction clamps. A lateral precontoured plate is placed submuscularly, and the most proximal holes are filled percutaneously. The medial incision begins distally at the adductor tubercle and is a straight incision made proximally in line with the femoral shaft. The underlying fascia is transected in line with the skin incision, and the vastus medialis is elevated. Care should be taken to avoid the descending geniculate artery, as well as its articular branch and the muscular branch to the vastus medialis. A lateral tibial plateau plate is contoured and placed. Nonoperative treatment of distal femoral fractures is rare, but relative indications for nonoperative treatment include frailty of the patient, lack of ambulatory status, a non-reconstructible fracture, or a stable fracture. These patients are placed in a long-leg cast followed by a hinged knee brace1. There are several other surgical fixation options, including lateral plating, retrograde intramedullary nailing, distal femoral replacement, and augmentation of a retrograde nail with a plate. Dual plating has several benefits, depending on the clinical scenario. Biomechanical studies have found that dual plating results in increased stiffness and construct strength2,3. Additional construct stability can be offered through the use of locking plates, particularly in osteoporotic bone. Taken together, this increased stability and construct strength can allow for earlier weight-bearing, which is particularly important for fractures in the geriatric population. Furthermore, the increased stiffness and construct strength make this procedure a favorable treatment option for nonunion, and it has been shown to result in lower rates of postoperative nonunion compared with lateral plating alone4-7. Adjunctive use of a medial plate also has been suggested to prevent varus collapse, particularly with metaphyseal comminution and poor bone quality2,3,8. Finally, in the periprosthetic fracture population, dual plating also removes the concern of incompatibility with a retrograde nail. The outcomes of dual plating are promising, given the severity of the injury. When comparing operative to nonoperative treatment outcomes, nonoperatively managed patients had worse functional outcomes and higher rates of complications related to immobility1. Dual plating of supracondylar fractures and intra-articular distal femoral fractures yields nonunion rates ranging from 0% to 12.5%, lower than the 18% to 20% reported with lateral locking plates4-7,9-12. This reduction in nonunions has been shown to lead to fewer revisions when compared with single-plating techniques7. In prior studies, 95% of nonunions treated with the dual-plating technique achieved union postoperatively11. One concern when utilizing the medial approach is critical damage to medial vascularity; however, this result has not been reported in the literature, and there is a safe operating window13. Despite the benefits of dual plating, there are relatively high rates of infection following dual plating (0% to 16.7%) compared with lateral plating alone (3.6% to 8.5%)5,14-17. However, many of these studies are small case series, highlighting that a surgeon's comfort and skill with these procedures is paramount to patient outcomes. Meticulous placement and contouring of lateral and medial plates are required to prevent malreduction of the articular block that creates a "golf-club deformity."18,19During the medial approach, be aware of descending geniculate artery-particularly its muscular branch, which is ∼5 cm from the adductor tubercle/medial epicondyle, and its root, which enters the compartment at the adductor hiatus at ∼16 cm13.

Are Femoral Stems in Primary Total Knee Arthroplasty Cost Effective in High Fracture Risk Patients? A Risk Model and Cost Analysis.

Femoral stemmed total knee arthroplasty (FS TKA) may be used in patients deemed higher risk for periprosthetic fracture (PPF) to reduce PPF risk. However, the cost effectiveness of FS TKA has not been defined. Using a risk modeling analysis, we investigate the cost effectiveness of FS in primary TKA compared with the implant cost of revision to distal femoral replacement (DFR) following PPF. A model of risk categories was created representing patients at increasing fracture risk, ranging from 2.5 to 30%. The number needed to treat (NNT) was calculated for each risk category, which was multiplied by the increased cost of FS TKA and compared with the cost of DFR. The 50th percentile implant pricing data for primary TKA, FS TKA, and DFR were identified and used for the analysis. FS TKA resulted in an increased cost of $2,717.83, compared with the increased implant cost of DFR of $27,222.29. At 50% relative risk reduction with FS TKA, the NNT for risk categories of 2.5, 10, 20, and 30% were 80, 20, 10, and 6.67, respectively. At 20% risk, FS TKA times NNT equaled $27,178.30. A 10% absolute risk reduction in fracture risk obtained with FS TKA is needed to achieve cost neutrality with DFR. FS TKA is not cost effective for low fracture risk patients but may be cost effective for patients with fracture risk more than 20%. Further study is needed to better define the quantifiable risk reduction achieved in using FS TKA and identify high-risk PPF patients.

Influence of build orientation and support structure on additive manufacturing of human knee replacements: a computational study.

Developing patient-specific implants has an increasing interest in the application of emerging additive manufacturing (AM) technologies. On the other hand, despite advances in total knee replacement (TKR), studies suggest that up to 20% of patients with elective TKR are dissatisfied with the outcome. By creating 3D objects from digital models, AM enables the production of patient-specific implants with complex geometries, such as those required for knee replacements. Previous studies have highlighted concerns regarding the risk of residual stresses and shape distortions in AM parts, which could lead to structural failure or other complications. This article presents a computational framework that uses CT images to create patient-specific finite element models for optimizing AM knee replacements. The workflow includes image processing in the open-source software 3DSlicer and MeshLab and AM process simulations in the commercial platform 3DEXPERIENCE. The approach is demonstrated on a distal femur replacement for a 50-year-old male patient from the open-access Natural Knee Data. The results show that build orientations have a significant impact on both shape distortions and residual stresses. Support structures have a marginal effect on residual stresses but strongly influence shape distortions, whereas conical support exhibits a maximum distortion of 18.5 mm. Future research can explore how these factors affect the functionality of AM knee replacements under in-service loading.

Geriatric Distal Femur Fractures Treated with Arthroplasty Are Associated with Lower Mortality but Greater Costs Compared with Open Reduction and Internal Fixation at 30 Days.

Distal femur fractures (DFFs) are common injuries with significant morbidity. Surgical options include open reduction and internal fixation (ORIF) with plates and/or intramedullary devices or a distal femur endoprosthesis (distal femur replacement [DFR]). A paucity of studies exist that compare the two modalities. The present study utilized a 1:2 propensity score match to compare 30-day outcomes of geriatric patients with DFFs who underwent an ORIF or DFR. The National Surgical Quality Improvement Program data from 2008 to 2019 were utilized to identify all patients who sustained a DFF and underwent either ORIF or DFR. This yielded 3,197 patients who underwent an ORIF versus 121 patients who underwent a DFR. A final sample of 363 patients (242 patients with ORIF vs. 121 with DFR) was obtained after a 1:2 propensity score match. Costs were obtained from the National Inpatient Sample database using multiple regression analysis and validated with a 7:3 train-test algorithm. Independent samples t-tests and chi-square analysis were conducted to assess cost and outcome differences, respectively. Patients who received a DFR had higher transfusion rates than ORIF (p = 0.021) and higher mean inpatient hospital costs (p = 0.001). Subgroup analysis for patients 80 years of age or older revealed higher 30-day unplanned readmission (0 vs. 18.2%; p < 0.001) and 30-day mortality (0 vs. 18.2%; p < 0.001) rates for patients undergoing ORIF compared with DFR. The total number of DFR cases needed to prevent one ORIF-related 30-day mortality for DFR for patients 80 years of age was 6 (95% confidence interval: 3.02-19.9). The mean hospital costs associated with preventing one case of death within 30 days from operation by undergoing DFR compared with ORIF was $176,021.39. Our results demonstrate higher rates of transfusion and increased inpatient costs among the DFR cohort compared with ORIF. However, we demonstrate lower rates of mortality for patients 80 years and older who underwent DFR versus ORIF. Future studies randomized controlled trials are necessary to validate the results of this study.

Management of Bone Loss in Revision Total Knee Arthroplasty: An International Consensus Symposium.

The evaluation, classification, and treatment of significant bone loss after total knee arthroplasty (TKA) continue to be a complex and debated topic in revision TKA (rTKA). Despite the introduction of new evidence and innovative technologies aimed at addressing the approach and care of severe bone loss in rTKA, there is no single document that systematically incorporates these newer surgical approaches. Therefore, a comprehensive review of the treatment of severe bone loss in rTKA is necessary. The Stavros Niarchos Foundation Complex Joint Reconstruction Center Hospital for Special Surgery, dedicated to clinical care and research primarily in revision hip and knee replacement, convened a Management of Bone Loss in Revision TKA symposium on June 24, 2022. At this meeting, the 42 international invited experts were divided into groups; each group was assigned to discuss questions related to 1 of the 4 topics: (1) assessing preoperative workup and imaging, anticipated bone loss, classification system, and implant surveillance; (2) achieving durable fixation in the setting of significant bone loss in revision TKA; (3) managing patellar bone loss and the extensor mechanism in cases of severe bone loss; and (4) considering the use of complex modular replacement systems: hinges, distal femoral, and proximal tibial replacements. Each group came to consensus, when possible, based on an extensive literature review and interactive discussion on their group topic. This document reviews each these 4 areas, the consensus of each group, and directions for future research.

Larger stem to bone diameter ratio predicts lower cemented endoprosthesis failure.

With continued advances in treatment options, patients with endoprosthetic reconstruction are living longer and consequently relying upon their devices for a longer duration. Major causes of endoprosthesis failure include aseptic loosening and mechanical failure. In the setting of tumor resection, loss of bone stock and use of radiation therapy increase the risk for these complications. As such, considerations of remaining native bone and stem length and diameter may be increasingly important. We asked the following questions: (1) What was the overall rate of endoprosthesis failure at a minimum of 5-year follow-up? (2) Does resection length increase implant failure rates? (3) Does implant size and its ratio to cortical width of bone alter implant failure rates? We retrospectively analyzed patient outcomes at a single institution between the years of 1999-2022 who underwent cemented endoprosthetic reconstruction at the hip or knee and identified 150 patients. Of these 150, 55had a follow-up of greater than 5 years and were used for analysis. Radiographs of these patients at time of surgery were assessed and measured for resection length, bone diameter, stem diameter, and remaining bone length. Resection percentage, and stem to bone diameter ratios were then calculated and their relationship to endoprosthesis failure were analyzed. Patients in this cohort had a mean age of 55.8, and mean follow-up of 59.96 months. There were 78 distal femoral replacements (52%), 16 proximal femoral replacements (10.7%), and 56 proximal tibial replacements (37.3%). There were five patients who experienced aseptic loosening and six patients who experienced mechanical failure. Patients with implant failure had a smaller mean stem to bone diameter (36% vs. 44%; p = 0.002). A stem to bone diameter of 40% appeared to be a breaking point between success and failure in this series, with 90% of patients with implant failure having a stem: bone ratio less than 40%. Stem to bone ratio less than 40% increased risk for failure versus stems that were at least 40% the diameter of bone (6/19 [31.6%] vs. 0/36 [0%]; odds ratio 0.68; p < 0.001). Resection length did not appear to have an impact on the rates of aseptic loosening and mechanical failure in this series. Data from this series suggests a benefit to using stems with a larger diameter when implanting cemented endoprostheses at the hip or knee. Stems which were less than 40% the diameter of bone were substantially more likely to undergo implant failure.