Management of complete intra-articular distal femur and patellar fractures in an achondroplastic young adult; small is challenging' revisited: a case-report

BACKGROUND

People with achondroplasia exhibit distinct physical characteristics, but their cognitive abilities remain within the normal range. The challenges encountered during surgical procedures and perioperative care for achondroplastic individuals, are underrepresented in the existing literature.

CASE PRESENTATION

In this report, the management of a 26-year-old North-African achondroplastic male is highlighted. The patient suffered a complete intra-articular distal femur fracture (AO/OTA 33-C1) and an ipsilateral patella fracture (AO/OTA 34-C1). The patient's unusual anatomical variations and the lack of suitable orthopedic implants posed significant surgical challenges, particularly in the context of a resource-limited developing country. Facial and spinal deformities, which are common in patients with achondroplasia, further complicated the anesthetic approach.

CONCLUSIONS

The limited information on operative management of fractures in achondroplastic patients necessitated independent decision-making and diverging from the convenient approach where clear guidance is available in the literature.

Titanium versus stainless steel alloy bridge plates for distal femur fractures: Does callus form earlier with titanium?

INTRODUCTION

Distal femur fractures account for 3-6% of all femur fractures. Internal fixation of most distal femur fractures with an anatomic lateral locking plate should permit some motion at the metaphyseal portion of the fracture when secondary bone healing is planned by the operating surgeon. While several studies have been performed evaluating union rates for distal femur fractures with stainless steel and titanium plates, the timing of callus formation between stainless steel and titanium implants used as bridge plates for distal femur fractures (AO/OTA 33-A and -C) has been investigated to a lesser extent. We hypothesize that callus will be visualized earlier with post-operative radiographs with titanium versus stainless steel bridge plates.

METHODS

We retrospectively reviewed a consecutive cohort of patients over 18 years of age with acute AO/OTA 33-A and 33-C fracture patterns treated with an isolated stainless steel or titanium lateral bridge plate within 4 weeks of injury by a single fellowship-trained orthopedic trauma surgeon from 2011 to 2020 at one academic Level 1 trauma center. An independent, fellowship-trained orthopedic trauma attending surgeon reviewed anterior-posterior (AP) and lateral radiographs from every available post-operative clinic visit and graded them using the Modified Radiographic Score for Tibia (mRUST).

RESULTS

Twenty-five subjects were included in the study with 10 with stainless steel and 15 with titanium plates. There were no significant differences in demographics between both groups, including age, sex, BMI, injury classification, open versus closed, mechanism, and laterality. Statistically significant increased mRUST scores, indicating increased callus formation, were seen on 12-week radiographs (8.4 vs. 11.9, p = 0.02) when titanium bridge plates were used. There were no statistically significant differences in mRUST scores at 6 or 24-weeks, but scores in the titanium group were higher in at every timepoint.

DISCUSSION

In conclusion, we observed greater callus formation at 12 weeks after internal fixation of 33-A and 33-C distal femur fractures treated with titanium locked lateral distal femoral bridge plates compared to stainless steel plates. Our data suggest that titanium metallurgy may have quicker callus formation compared to stainless steel if an isolated, lateral locked bridge plate is chosen for distal femur fracture fixation.

Revision total knee arthroplasty with periprosthetic distal femoral fracture

Treatment strategies for periprosthetic distal femoral fracture depend on the type of fracture, level with respect to the prosthesis, and prosthesis fixation. The usual treatment is internal fixation by nail or locking plate. This can be more difficult when the fracture is close to the joint, is destabilizing the prosthesis or is associated with reduced bone stock, and implant exchange should be considered, depending on the patient's health status. The aim is to obtain the fastest possible recovery while limiting complications and minimizing surgery time for often frail and elderly patients. The present study details the implant revision technique in periprosthetic distal femoral fracture, which requires experience in traumatology and prosthetic revision and material adapted to the situation. LEVEL OF EVIDENCE: V, expert opinion.

Risk of reverse golf club deformity with medial plating of distal femur fracture

INTRODUCTION

This study described a deformity induced by medial plating of supracondylar distal femur fractures using plates that are precontoured for other anatomic locations.

MATERIALS AND METHODS

OTA/AO 33A fractures were created in 12 sawbone femurs and fixed with either a proximal humerus locking plate (PH), an ipsilateral lateral tibial plateau plate (LTP), or an ipsilateral medial distal tibial plate (MDT). A motion capture system measured changes in length and rotation of the distal femur as the plate was applied. Each plate underwent four trials and the mean and standard deviation (SD) for each measurement was reported. An analysis of variance with post hoc Tukey test compared malreduction measures between plate types.

RESULTS

All plates consistently created a varus deformity. There was lateral lengthening with a compensatory medial shortening and an increase in the lateral distal femoral angle. The distal fracture fragment was laterally translated, and internally rotated. The PH plate had significantly greater lateral length (27.39 mm SD 4.78, p = 0.007), shorter medial length (13.57 mm SD 4.99, p = 0.028), greater lateral translation (28.82 mm SD 5.70, p = 0.010) and greater widening of the lateral distal femoral angle (28.54° SD 4.98, p < 0.001) than the LTP and MDT plates. The MDT plate had significantly greater angulation anteriorly (8.40° SD 1.07, p < 0.001) and laterally (7.63° SD 3.10, p = 0.002) than the PH and LTP plates. There was no significant difference between plates in internal rotation (PH: 3.07° SD 2.79; LTP: 2.05° SD 1.05; MDT 3.81° SD 3.56; p = 0.659).

CONCLUSION

When dual plating supracondylar distal femur fractures, poor plate positioning and a mismatch between plate contour and the slope of the medial distal femur can lead to varus angulation, internal rotation, and lateral translation or a "reverse golf club deformity". After comparing three types of precontoured plates, the authors recommend initial evaluation of the ipsilateral proximal tibial plate when placing a plate along the medial distal femur.

LEVEL OF EVIDENCE

IV.

A Simple Intraoperative Technique for Restoring Rotational and Length Alignment After Distal Femur Resection and Endoprosthesis Reconstruction: A Technical Note

Restoring femoral rotation alignment and limb length after distal femur resection and endoprosthetic reconstruction is crucial to avoid poor outcomes. This technical note presents a simple and reliable intraoperative technique for restoring femoral rotation and length during distal femur resection and endoprosthetic reconstruction without the need for extensive preoperative planning or complex perioperative modalities. The method utilizes an external fixator frame as a guiding device to assess and restore the native alignment. This approach provides a practical alternative to relying solely on the position of the linea aspera, which has been shown to be an unreliable landmark for rotational alignment. Implementing this technique can contribute to improved functional outcomes in patients undergoing distal femur endoprosthetic reconstruction.

The sacroiliac joint: An original and highly sensitive tool to highlight altered bone phenotype in murine models of skeletal disorders

Bone disorders may affect the skeleton in different ways, some bones being very impaired and others less severely. In translational studies using murine models of human skeletal diseases, the bone phenotype is mainly evaluated at the distal femur or proximal tibia. The sacroiliac joint (SIJ), which connects the spine to the pelvis, is involved in the balanced transfer of mechanical energy from the lumbar spine to the lower extremities. Because of its role in biomechanical stress, the SIJ is a region of particular interest in various bone diseases. Here we aimed to characterize the SIJ in several murine models to develop a highly reliable tool for studying skeletal disorders. We performed a 12-month in vivo micro-computed tomography (micro-CT) follow-up to characterize the SIJ in wild-type (WT) C57BL/J6 mice and compared the bone microarchitecture of the SIJ and the distal femur at 3 months by micro-CT and histology. To test the sensitivity of our methodology, the SIJ and distal femur were evaluated at 3 and 6 months, in 2 murine models of skeletal disorder, X-linked hypophosphatemia (Hyp mice) and HLA-B27 transgenic mice and compared to WT mice. A multimodal analysis was performed, using a combination of microCT and histological analysis. With the Hyp model, the SIJ displayed more bone microarchitecture alterations than the distal femur. Hyp mice showed a significant reduction in trabecular bone at both the distal femur and sacral slope as compared with WT mice, with a significant positive correlation between trabecular bone parameters of the distal femur and sacral side of the SIJ. Furthermore, trabecular bone parameters (Bone Volume/Total Volume (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N), trabecular pattern factor (Tb.Pf)) were significantly increased compared to femoral parameters at the SIJ. The sacral articular cortical bone, which is indicative of osteoarticular lesions, was altered in Hyp mice. Interestingly, in accordance to previous studies, HLA-B27 transgenic mice did not show any osteoarticular lesions as compared with WT mice. Cortical bone parameters (thickness, porosity), as well as scoring performed with double blinding, did not show difference between the 2 genotypes. The characterization and evaluation of the SIJ surface appears very sensitive to emphasize alterations of bone and joint. The SIJ may represent a valuable tool to investigate both bone and local osteoarticular alterations in murine models of skeletal disorders and might be a relevant site for assessing the response to treatment of chronic bone diseases.

Five or more gender- and size-diverse customizations of distal femur prostheses are needed to improve fit for Chinese knees

PURPOSE

Mismatch between partial imported prostheses and Chinese anatomy affects the clinical outcome of the procedure. The purpose of this study was to measure the anatomical dimensions of Chinese distal femurs to provide guidance for the design of more compatible distal femoral prostheses.

METHODS

A total of 406 healthy distal femurs were reconstructed and measured. Consistency of these measurements and differences in sides, gender, and populations were examined. Parameter correlations were analyzed, and pairs with strong correlations underwent linear regression analysis. The design of distal femoral prostheses was referenced from the results of K-means and hierarchical clustering analysis.

RESULTS

Ten parameters were measured, including the trans-epicondylar axis, width of the distal femur (ML), anteroposterior diameter of the distal femur (AP), etc. The intra-class correlation coefficient ranged from 0.795 to 0.999 for intra-observer consistency, and from 0.796 to 0.998 for inter-observer consistency. Males exhibited significantly larger parameters than females, except for the posterior condylar angle (all P values < 0.05). Compared to other populations, substantial differences were observed for most parameters, such as ML, AP, width of lateral femoral condyle, etc. (all P values < 0.05). Clustering analysis suggested that distal femoral prostheses should include at least five sizes to adequately accommodate the sampled population. ML sizes for males were 68, 70, 83, 73, and 89 mm, and for females 64, 65, 71, 67, and 77 mm. AP sizes for males were 56, 60, 60, 64, and 64 mm, and for females 48, 52, 54, 57, and 58 mm.

CONCLUSIONS

Chinese distal femur morphology, as analyzed using 3D techniques, varies significantly between genders and when compared with international data. For improved patient fit, the creation of five or more distal femur prostheses, diversified by gender and size and informed by the associated morphological parameters, is recommended.

LEVEL OF EVIDENCE

IV.

Management of segmental defects post open distal femur fracture using a titanium cage combined with the Masquelet technique A single-centre report of 23 cases

INTRODUCTION

The segmental bone defects post open distal femur fracture presents a reconstructive challenge, which often requires extreme solutions. The present study reviewed a new treatment strategy which used a cylindrical titanium mesh cage as an adjunct to the Masquelet technique.

METHODS

We retrospectively reviewed a consecutive series of 23 patients treated for segmental bone defects post open distal femur fracture using a titanium mesh cage combined with the Masquelet technique under a 2-staged protocol in our institution from 2017 to 2021. The study group consisted of 13 men and 10 women with an average age of 44.1 years. The surgical debridement was performed with antibiotic polymethylmethacrylate (PMMA) cement spacer implanted into the bone defect combined with cement-wrapped plate stabilization, or antibiotic beads with vacuum sealing drainage (VSD) to cover the wound. The second stage of the Masquelet technique for bone defect repair began at least 4-6 weeks after the first stage, once all signs of possible infection were eliminated. After the cement spacer was removed, the definitive reconstruction was completed with exchange to a cylindrical titanium mesh cage filled with cancellous autograft within the induced membrane. The bone defect with cage was stabilized with a distal femoral Less Invasive Stabilization System (LISS). The radiological and clinical records of the enrolled patients were retrospectively analyzed.

RESULTS

The mean follow-up was 38.6 months. The average number of operations before the second stage was 1.3. The mean interval between the two stages was 12.7 weeks. The average length of the defect measured 8.3 cm (ranging from 6.1 to 12.4 cm). All the defects filled with autograft within the cage achieved bony union, with a mean healing time of 8.4 months. At the latest follow-up, the mean knee extension measured 6.2° (ranging from 0° to 20°), and the mean flexion measured 101.8° (ranging from 60° to 120°). Complications included two instances of superficial stitch abscess, which eventually healed.

CONCLUSIONS

The use of a titanium cage implanted into an induced membrane in a 2-staged Masquelet protocol could achieve satisfactory clinical outcomes in cases of segmental defects following open distal femur fractures.

Recurrent chondromyxoid fibroma of the distal femur treated with percutaneous cryoablation

Chondromyxoid fibroma is a rare, benign tumor of the bone with excellent prognosis but a high rate of recurrence. We report a patient presenting with pain and a history of chondromyxoid fibroma of the distal left femur previously treated with multiple prior curettage and bone graft procedures. Magnetic resonance imaging and histopathology indicated a recurrence of tumor. Due to the small size of the tumor recurrence and challenges associated with prior open surgery, the patient underwent cryoablation of the lesion with computed tomography guidance. Follow-up 18 months later indicated a resolution of pain and improvement on magnetic resonance imaging, and no concerns after 20 months. To our knowledge, this is the first reported case of chondromyxoid fibroma treated with cryoablation. This case suggests cryoablation could be considered in the setting of recurrent chondromyxoid fibroma for local tumor control.

What to improve: Results of fixed-hinge knee endoprosthesis reconstructions over 40 years in a single tumor center

INTRODUCTION

Over the past decades, numerous structural changes in implants, medical treatments, and surgical techniques have been made for Malignant Bone Tumors (MBT) around the knee. However, the overall care improvement is still unclear. The method is crucial when analyzing outcomes in surveys involving tumors, and a thorough assessment of the mortality is mandatory because death acts as competing event. The aims of this study were: 1) a comprehensive and longitudinal assessment of the revisions with an extensive follow-up and adequate methods; 2) a complete mortality review to consider competing risks.

HYPOTHESIS

The hypothesis was that some prosthesis's structural improvements were made while the surgical toll increased as well as an improvement of mortality was also expected.

MATERIAL AND METHODS

Analyses were performed on 248 patients with MBT (mean follow-up was 8.7 years, surgeries between 1972 and 2017). Three prosthesis models were successively used over time: 120 Guepar (older model), 42 Tornier, and 86 Stanmore (more recent model). The primary outcome was the assessment of revisions sorted out according to Henderson: type-1 soft-tissue failures or instability, type-2 aseptic loosening, type-3 structural failures, type-4 periprosthetic infections, type-5 tumoral progression. Death and amputations were considered as competing events. An extensive assessment of mortality was performed by merging the dataset with the French register of Deaths (INSEE). Cumulative probabilities were computed at 2, 5, 10, and 15 years and compared with Gray's tests.

RESULTS

The overall 5-year survival was, 80% (95% CI: 73-87) for Guepar, 69% (95% CI: 56-84) for Tornier, and 71% (95% CI: 62-82) for Stanmore (p=0.4). The 5-year cumulative risks for type-1 were 5% (95% CI: 1-9), 9% (95% CI: 0-18), and 17% (95% CI: 9-25) for Guepar, Tornier, and Stanmore, respectively (p=0.01). The 15-year cumulative risks for type-2 were 22% (95% CI: 15-39), 8% (95% CI: 0-17) and 8% (95% CI: 2-14) for Guepar, Tornier, and Stanmore, respectively (p=0.10). Ten patients had an implant failure, nine Guepar, and one Tornier. The 5-year cumulative risks for type-4 were 7% (95% CI: 2-12), 19% (95% CI: 7-31), and 12% (95% CI: 5-18) for Guepar, Tornier, and Stanmore, respectively (p=0.08). There were 29 tumoral progressions; the 15-year risks were 16% (95% CI: 2-22), 2% (95% CI: 0-7%), and 12% (95% CI: 4-19%) for Guepar, Tornier, and Stanmore, respectively (p=0.08). No difference whatsoever was found between the proximal tibial and distal femur.

CONCLUSION

There were some improvements in prosthesis design (forged steel instead of cast steel) and probably also in cemented stem fixation, but not in prosthetic joint infection and local recurrence over forty years. The overall mortality did not change significantly over the last 40 years amongst this specific cohort of patients who benefited from a hinge reconstruction prosthesis.

LEVEL OF EVIDENCE

III; comparative case series with sensibility analysis.

Current standard of care for distal femur fractures in Germany and Switzerland

BACKGROUND

Distal femur fractures occur with an incidence of 4.5/100,000 and show a prevalence of 0.4%. Causes include low-impact trauma in older patients and high-impact trauma in younger patients without pre-existing medical conditions. The aim of this study was to perform a comprehensive evaluation of trauma mechanisms, trauma-promoting factors, comorbidities, medication history and type of surgical care to provide an overview of the causes of injury and the most appropriate therapeutic approach.

METHODS

In this multicenter cohort study a retrospective analysis of 229 patients who sustained a distal femur fracture between January 2011 and December 2020 was performed. Individual fracture patterns, fracture predisposing factors, concomitant disease profiles, medication history, treatment strategy and associated complications were analyzed.

RESULTS

229 patients were included in the retrospective analysis. A total of 113-type 33 A, 50-type 33 B and 66-type 33 C fractures were diagnosed, of whom 92% received a lateral locking plate osteosynthesis. There was a complication in 14.4% of all cases, of which 6.1% were attributable to infection. Significant risk factors for developing a complication were an increased BMI (29.9 ± 8.5 kg/m2; p = 0.04), fracture displacement of over half a shaft width (p < 0.001) and AOC fractures (p < 0,016), specifically C2 fractures (p < 0,008).

CONCLUSION

In this multicenter retrospective cohort study, lateral locking plate osteosynthesis was the method of choice and was selected in over 90% of cases, regardless of the fracture classification and risk factors. A complication rate of 14.4% emphasizes the necessary analysis of patient- and care-specific risk factors and a resulting adjustment of the therapy strategy. An increased BMI (29.9 ± 8.5 kg/m2; p = 0.04), fracture displacement of over half a shaft width (p < 0.001) and AOC fractures (p < 0,016), specifically C2 fractures (p < 0,008) increase the risk of developing a complication and should prompt an early switch to a treatment strategy that provides more stability.

Medial augmentation plating of aseptic distal femoral nonunions

BACKGROUND

Distal femur nonunions are well-recognized contributors to persistent functional disability, with limited data regarding their treatment options. In the current study, we asked whether additional medial augmentation plating is a feasible treatment option for patients with aseptic distal femoral nonunion and intact lateral implants.

METHODS

We conducted a single-center, retrospective study including 20 patients treated for aseptic distal femoral nonunion between 2002 and 2017. The treatment procedure included a medial approach to the distal femur, debridement of the nonunion site, bone grafting and medial augmentation plating utilizing a large-fragment titanium plate. Outcome measures were bone-related and functional results, measured by the Hospital for Special Surgery Knee Rating Scale (HSS) and the German Short Musculoskeletal Function Assessment questionnaire (SMFA-D).

RESULTS

Eighteen of 20 nonunions showed osseous healing at 8.16 ± 5.23 (range: 3-21) months after augmentation plating. Regarding functional results, the mean HSS score was 74.17 ± 11.12 (range: 57-87). The mean SMFA-D functional index was 47.38 ± 16.78 (range 25.74-71.32) at the last follow-up. Index procedure-associated complications included two cases of persistent nonunion and one case of infection.

CONCLUSIONS

According to the assessed outcome measures, augmentation plating is a feasible treatment option, with a high proportion of patients achieving bony union and good functional outcomes and a few patients experiencing complications.

Aseptic loosening of tumor prostheses in distal femur after revision surgery: a retrospective study

BACKGROUND

Tumor prostheses of the distal femur after revision surgery is associated with high rates of aseptic loosening, which has introduced great challenges to the survival of patients, but only a few studies have evaluated their X-ray imaging. The purpose of this study was to analyze the risk factors for recurrence of aseptic loosening and make recommendations to reduce the incidence of aseptic loosening after revision surgery of tumor prostheses in the distal femur.

METHOD

A retrospective analysis was performed on 23 patients who had revision surgery for distal femur prostheses due to aseptic loosening between June 2002 and June 2021. They were divided into two groups based on the condition of the prostheses after revision surgery: loosening group (9 patients) and control group (14 patients). Following the initial replacement, the length and diameter of the prosthetic intramedullary stem were measured through the standard full-length anteroposterior X-ray imaging of both lower limbs. The osteotomy length, femoral length and diameter, femoral intramedullary stem diameter, hip-knee-ankle angle (HKAA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and so on were measured as well. Following that, statistical analysis was performed.

RESULTS

Patients in the loosening group had statistically significant differences in the ratio of prostheses length to femur length (71.89 ± 6.62) and the ratio of intramedullary stem diameter to femoral diameter (25.50 ± 6.90) (P < 0.05), when compared to the control group. The HKAA (175.58 ± 2.78), mLDFA (94.42 ± 2.57), and the deviation angle between the lower limb alignment and the tibial prostheses force line (2.23 ± 1.09) in the loosening group were significantly different from those in the control group (P < 0.05) on postoperative radiographs of the entire length of the lower limbs. The lowest score in intramedullary manubrium I indicated less osteolysis, while the highest score in intramedullary manubrium III indicated the most serious osteolysis, and the difference was statistically significant (P < 0.05).

CONCLUSIONS

Our study suggests that the use of longer and thicker intramedullary stems can effectively decrease the occurrence of aseptic loosening. Additionally, it is important to avoid using the original prostheses and reconstruct the standard line of lower limb force to further reduce the incidence of aseptic loosening. It is crucial to closely monitor the distal segment of the intramedullary stem for osteolysis after surgery.

Perioperative allogenic blood transfusions are associated with increased fracture related infection rates, but not nonunion in operatively treated distal femur fractures

INTRODUCTION

Distal femur fractures are common injuries that remain difficult for orthopedic surgeons to treat. High complication rates, including nonunion rates as high as 24% and infection rates of 8%, can lead to increased morbidity for these patients. Allogenic blood transfusions have previously been identified as risk factors for infection in total joint arthroplasty and spinal fusion surgeries. No studies have explored the relationship between blood transfusions and fracture related infection (FRI) or nonunion in distal femur fractures.

METHODS

418 patients with operatively treated distal femur fractures at two level I trauma centers were retrospectively reviewed. Patient demographics were collected including age, gender, BMI, medical comorbidities, and smoking. Injury and treatment information was also collected including open fracture, polytrauma status, implant, perioperative transfusions, FRI, and nonunion. Patients with less than three months of follow up were excluded.

RESULTS

366 patients were included in final analysis. One hundred thirty-nine (38%) patients received a perioperative blood transfusion. Forty-seven (13%) nonunions and 30 (8%) FRI were identified. Allogenic blood transfusion was not associated with nonunion (13% vs 12%, P = 0.87), but was associated with FRI (15% vs 4%, P<0.001). Binary logistic regression analysis identified a dose dependent relationship between number of perioperative blood transfusions and FRI: total transfusion ≥2 U PRBC RR= 3.47(1.29, 8.10, P = 0.02), ≥3 RR= 6.99 (3.01, 12.40, P<0.001), and ≥4 RR= 8.94 (4.03, 14.42, P<0.001).

DISCUSSION

In patients undergoing operative treatment of distal femur fractures, perioperative blood transfusions are associated with increased risk of fracture related infection, but not the development of a nonunion. This risk association increases in a dose-dependent relationship with increasing total blood transfusions received.

Intraoperative physician assessment of bone: correlation to bone mineral density

This study evaluated the intraoperative physician assessment (IPA) of bone status at time of total knee arthroplasty. IPA was highly correlated with distal femur and overall bone mineral density. When IPA identifies poor bone status, formal bone health assessment is indicated.

PURPOSE

Intuitively, intraoperative physician assessment (IPA) would be an excellent measure of bone status gained through haptic feedback during bone preparation. However, no studies have evaluated the orthopedic surgeon's ability to do so. This study's purpose, in patients undergoing total knee arthroplasty (TKA), was to relate IPA with (1) the lowest bone mineral density (BMD) T-score at routine clinical sites; and (2) with distal femur BMD.

METHODS

Seventy patients undergoing TKA by 3 surgeons received pre-operative DXA. Intraoperatively, bone quality was assessed on a 5-point scale (1 excellent to 5 poor) based on tactile feedback to preparation. Demographic data, DXA results, and IPA score between surgeons were compared by factorial ANOVA. Lowest T-score and distal femur BMD were associated with IPA using Spearman's correlation.

RESULTS

The mean (SD) age and BMI were 65.8 (7.6) years and 31.4 (5.1) kg/m², respectively. Patient demographic data, BMD, and IPA (mean [SD] = 2.74 [1.2]) did not differ between surgeons. IPA correlated with the lowest T-score (R = 0.511) and distal femur BMD (R = 0.603-0.661). Based on the lowest T-score, no osteoporotic patients had an IPA above average, and none with normal BMD was classified as having poor bone.

CONCLUSIONS

IPA is highly correlated with local (distal femur) and overall BMD. This study supports the International Society for Clinical Densitometry position that surgeon concern regarding bone quality should lead to bone health assessment. As IPA is comparable between surgeons, it is logical this can be widely applied by experienced orthopedic surgeons. Future studies evaluating IPA at other anatomic sites are indicated.

Is lateral femoral condyle hypoplasia a feature of genu valgum? A morphological computed tomography study of 200 knees

BACKGROUND

Young surgeons are taught that genu valgum deformity is associated with hypoplasia of the lateral femoral condyle, despite the absence of supporting evidence. The objective of this study was to determine whether the lateral condyle was hypoplastic in genu valgum, by assessing the morphological features of the distal femur and their variations according to the severity of the coronal deformity.

HYPOTHESIS

The lateral femoral condyle is not hypoplastic in genu valgum deformity.

MATERIAL AND METHODS

The 200 included patients treated by unilateral total knee arthroplasty were divided into five groups based on their preoperative hip-knee-ankle (HKA) angle. The HKA angle, valgus cut angle (VCA), and anatomical lateral distal femoral angle (aLDFA) were measured on long-leg radiographs. Computed tomography images were then used to measure the medial and lateral anterior-posterior condylar lengths (mAPCL and lAPCL) and condylar thicknesses (mCT and lCT), distal femoral torsion (DFT), medial and lateral posterior condylar heights (mPCH and lPCH), and medial and lateral condylar volumes (mCV and lCV).

RESULTS

No significant differences were demonstrated across the five mechanical-axis groups for mAPCL, lAPCL, mCT, lCT, mPCH, or lPCH. The groups differed significantly regarding the VCA (p<0.0001), aLDFA (p<0.0001), DFT (p<0.0001), and mCV/lCV ratio (p<0.0001). VCA and aLDFA were smaller when the valgus exceeded 10°. DFT was similar in all varus knees (2.2°-2.6°) but significantly greater for knees with moderate (4.0°) or severe (6.2°) valgus. Finally, lCV was greater than mCV in valgus knees compared to varus knees.

CONCLUSION

The presence of lateral condyle hypoplasia in knees with genu valgum seems open to question. Apparent hypoplasia noted during the standard physical examination may be chiefly ascribable to distal valgus of the femoral epiphysis in the coronal plane and, with the knee flexed, to distal epiphyseal torsion, whose severity increases with the degree of valgus deformity. These considerations should be taken into account when performing distal femoral cuts for TKA, to ensure the restoration of normal anatomy in patients with genu valgus.

LEVEL OF EVIDENCE

IV.

A Morphometric Study of the Distal Femoral Resected Surface In Osteoarthritis Knees of the Patients in Southwest China and a Comparison with Femoral Components in Six Total Knee Arthroplasty Systems

OBJECTIVE

Mismatch between the femoral component and the resected surface is related to the postoperative clinical outcome. This study aimed to measure the morphometric features of the distal femoral resected surfaces in patients with osteoarthritis in southwestern China and to compare the measured morphometric data with six commonly used total knee arthroplasty (TKA) femoral components in China.

METHOD

The computer tomography (CT) images of a total of 406 knees from 203 osteoarthritis patients who underwent TKA from January 2018 to December 2021 were imported into Mimics 21.0 software to reconstruct the three-dimensional (3D) model of the femur. Morphometric data of the distal femoral resected surfaces were measured after the completion of simulated bone resection in the software. The data included the medial-lateral (ML) dimension, anterior-posterior (AP) dimension, and the aspect ratio (AR) (AR = ML/AP), which were compared between genders with independent sample t-tests. In addition, we plotted the scatter diagram of those morphometric data in Origin software, and the linear fits of ML versus AP and AR versus AP were performed and compared for the six femoral components commonly used in enrolled patients in China.

RESULTS

The mean ML dimension, the mean AP dimension, and the mean AR value measured for Chinese knees were 66.62 ± 4.57 mm, 58.10 ± 3.74 mm, and 1.15 ± 0.06 respectively. All dimensions were significantly larger in males than in females, including the calculated values for AR (P < 0.05). The fitted lines for males showed that the ML dimensions tended to be wider compared to femoral components of a given AP dimension. Females tended to have wider ML dimensions compared to small femoral components and, on the other hand, narrower ML dimensions compared to large femoral components.

CONCLUSION

The femoral component of the current commonly used TKA prosthesis in China may not be perfectly matched to the distal femoral resected surface of patients in southwestern China. Male patients tended to underhang in all dimensions of the ML dimension. Female patients with shorter AP lengths are more likely to experience underhang, whereas those with longer AP lengths are more likely to develop overhangs. Therefore, we recommend multiple ML width options for a given AP length to more appropriately match the Chinese femoral anatomy.

The anatomical shape of the distal femur is an independent risk factor for aseptic loosening following one-stage septic knee revision using rotating hinge knee prosthesis

PURPOSE

Aseptic loosening (AL) is the second most common reason for failure after one-stage septic knee revision. In this context, the goal of the study is to identify risk factors for AL following one-stage septic knee revision using rotating hinge implants. We aimed to answer the following research question: How does the anatomical shape of the distal femur represent an independent risk factor for AL following one-stage septic knee revision arthroplasty?

METHODS

Patients, who had undergone re-revision surgery due to AL of the rotating hinge knee prosthesis after one-stage septic knee revision arthroplasty between January 2008 and December 2018, were included. For this purpose, 41 patients with AL after one-stage septic knee revision using rotating hinge implants and 37 controls without any revision surgery at latest follow-up were included in this study. Using standardized anteroposterior (AP) views of the knee in all patients, we measured the inner diameter of the femur 20 cm proximally from the joint line and at a point 2 cm proximally from the adductor tubercle.

RESULTS

Among the vast majority of AL cases, we identified an isolated loosening of the femoral component. The AL group showd a high distribution of the Type C according to the Citak classification with 75.7%. Contrary to this, with 24.3% (p < 0.001) the amount of Type C cases was relatively low in the control group. Consequently, Type C configurations of the distal femur represent an independent risk factor for AL with an approximately sevenfold higher risk for AL compareed to Type A and Type B.

CONCLUSIONS

The novel radiological classification system of the distal femur shows that the Type C subtype is an independent and main risk factor for AL after one-stage septic knee revision using rotating hinge knee implants.

Distal Femoral Valgus Resection Angle in Conventional Total Knee Arthroplasty - a CT Scanogram Study

Objectives

In conventional total knee arthroplasty (TKA), the distal femur valgus resection angle (DFVA) is decided either by measuring the specific resection angle for each patient on preoperative anteroposterior hip-knee-ankle (HKA) weight-bearing radiograph or using a fixed resection angle of five to seven degrees, when such facilities are not available. This study aims to measure the DVFA in TKA patients using preoperative HKA non-weight-bearing computerized tomography (CT) scanogram scout films and determine its relation with preoperative coronal plane lower-limb deformities.

Methods

In this retrospective radiological study, various measurements were performed on bilateral, preoperative hip-knee-ankle CT scanograms of 73 knee osteoarthritis patients who had presented for total knee replacement surgery using a standard protocol. The angle between the femoral anatomical axis and femoral mechanical axis was measured as the femoral mechanical anatomical angle (FMAA), which corresponds to the surgical DFVA. The angle between the femoral and tibial mechanical axes was measured as mechanical femorotibial angle (MFTA). The correlation between FMAA and MFTA was studied.

Results

The mean FMAA for the study group was 6.45° (range 3° to 11°, SD 1.17°). The MFTA for the study group ranged from 24° varus to 14° valgus. The alignment was valgus in 14.4% (n=21), varus in 84.2% (n=123), and "0 degrees" in 1.3% (n=2). With valgus coronal alignment taken as positive and varus as negative, the Pearson's correlation coefficient for MFTA with FMAA was r = -0.5183 (p<0.001), indicating that valgus knees tended to have a smaller FMA angle and varus knees tended to have a larger FMA angle.

Conclusion

In the non-availability of individualized measurements, in primary TKA, we recommend setting DFVA as five degrees for valgus deformities, six degrees for mild/moderate varus deformities (MFTA <15°) and seven degrees for severe varus deformities (MFTA > 15°).

Endosteal plating for the treatment of malunions and nonunions of distal femur fractures

PURPOSE

To describe the surgical technique and the outcome of a case series of nonunion and malunion of distal femur fractures treated with an endosteal medial plate combined with a lateral locking plate and with autogenous bone grafting.

METHODS

We retrospectively analyzed a series of patients with malunion or nonunion of the distal femur treated with a medial endosteal plate in combination with a lateral locking plate, in a period between January 2011 and December 2019, Database from chart review was obtained including all the clinical relevant available baseline data (demographics, type of fracture, mechanism of injury, time from injury to surgery, number of previous surgical procedures, type of bone graft, and type of lateral plate). Time to bone healing, limb alignment at follow-up and complications were documented.

RESULTS

Ten patients were included into the study: 7 male and 3 female with mean age of 48.3 years (range 21-67). The mechanism of trauma was in 8 cases a road traffic accident and in 2 cases a fall from height. According to AO/OTA classification 5 fractures were 33 A3, 3 were 33 C1, 1 was 33 C2 and 1 was 33 C3. The average follow up was 13.5 months. In all cases but one bony union was achieved. Bone healing was observed in average 3.3 months after surgery. No intraoperative or postoperative complications were reported.

CONCLUSION

A medial endosteal plate is a useful augmentation for lateral plate fixation in nonunion or malunion following distal femur fractures, particularly in cases of medial bone loss, severe comminution, or poor bone quality.

LEVEL OF EVIDENCE

Level IV (retrospective case series).

Physeal fusion status and lesion size are more important than patient age for healing of juvenile osteochodritis dessicans lesions of the distal femur

PURPOSE

The purpose of the study was to evaluate the effect of skeletal age and lesion size, location, and grade on the success of nonoperative treatment for juvenile osteochondritis dissecans (OCD). It is hypothesized that skeletal maturity, including a combination of maturation phenotypes, correlates with nonoperative lesion healing.

METHODS

The clinical and radiographic data on 52 patients aged 7-20 years treated for OCD of the distal femur between 2010 and 2019 were retrospectively reviewed. Knee radiographs were assessed for number of lesions present and lesion location, size, and stage. Assessments of skeletal maturation were performed on all antero-posterior knee radiographs using the Roche, Wainer, and Thissen (RWT) method. Patients were categorized as healed if they demonstrated no pain on clinical examination. The relationship between skeletal maturity and nonoperative lesion healing was determined using Spearman rank correlations on available variables.

RESULTS

Neither chronological nor skeletal age was associated with surgical status (Rho = 0.03, n.s., and Rho = 0.13, n.s., respectively) or the healing status of nonoperatively treated OCD lesions (Rho = 0.44, n.s., and Rho = 0.03, n.s., respectively). Epiphyseal fusion status of the distal femoral physis was moderately correlated with nonoperative healing, but was not statistically significant (lateral femoral physis: Rho = 0.43, p = 0.05; medial femoral physis: Rho = 0.43, n.s.). Lesion length correlated with surgical status (Rho = - 0.38, p = 0.009).

CONCLUSION

The extent of fusion of the distal femoral physis (multi-stage grading) may be more strongly correlated with nonoperative healing than other markers of skeletal maturity or chronological age. Clinicians can use this as an additional radiographic sign when considering nonoperative treatment for juvenile OCD lesions in the distal femur. OCD lesion length and physeal fusion status appear to be more important for healing than patient age.

Three-dimensional printed customized uncemented unipolar prosthesis combined with ligament reconstruction for tumorous defect of the distal femur in children

BACKGROUND

Hemiarthroplasty following tumor resection of the distal femur in children provides a chance to preserve the proximal tibial physis for limb elongation. Based on three-dimensional (3D) printing technology, the uncemented unipolar prosthesis with joint stability reinforced structures (JSRSs) was custom-designed for our cases. This study aimed to describe the design and assess the short-term outcomes of this refined prosthetic hemiarthroplasty.

METHODS

Seven patients (four females and three males) received 3D-printed customized uncemented unipolar prosthesis for hemiarthroplasty after removal of the distal femur, from September 2019 to October 2020 at our Orthopedics department. The limb function, growth of the preserved proximal tibial physis, joint stability, and limb length discrepancy (LLD) were assessed. Complications were recorded.

RESULTS

Six patients survived with no evidence of metastasis or local recurrence at the last follow-up, and one patient died of lung metastasis at 19 months postoperatively. Follow-up ranged from 19 to 32 months, with an average of 26 months. Elongation of the tibia was observed in all cases. At the last follow-up, four patients exhibited equal growth length compared with the healthy contralateral tibia. LLD ranged from 0.8 to 1.6 cm with a mean of 1.3 cm. The average knee range of motion was 95.3° of flexion and 4.5° of extension. All patients achieved satisfactory postoperative limb function with a mean MSTS score of 25.8. The results of the drawer, Lachman, and pivot shift tests were negative in all patients. During follow-up, painless joint space narrowing was observed in two patients. The screw for ligament fixation loosened in one of the seven patients at 17 months postoperatively. No subluxation of the joint, angular deformity, or breakage of the implant was detected in the remaining patients.

CONCLUSIONS

3D-printed customized uncemented unipolar prosthesis with JSRS would be a good choice for reconstructing tumorous defect in the distal femur in children.

The flexibility and convenience of using a standard orthopaedic table in peri-articular knee fractures: Allowing ligamentotaxis and improving imaging accessibility

Tibial plateau and distal femoral fractures are common injuries presenting a significant operative challenge. Complexity of the fracture often needs multi-planar surgical access. A combined two-staged procedure is frequently suggested both in supine and prone position to address this issue. However, this will significantly increase the operative time and eventually impact the outcome, in addition to the complications associated with prone positioning. In this study we used a standard orthopaedic table to position these patients in order to grant access to the postro-medial and a postro-lateral structures while the patient stays in supine setup, at the same time, giving the flexibility to change the alignment from valgus to varus and vice versa. This facilitates fracture reduction while addressing the anatomical structure of the knee. A further advantage is the unobstructed imaging access throughout the surgical fixation. This facilitates the reduction in operative time hence leading to a better outcome in these difficult fractures. We tested this positioning technique in more than 40 patients over a 4-year period at two different centres in the United Kingdome. We found that this approach is safe, reproducible and relatively easy to set up in the two centres.

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 non-periprosthetic distal femur fragility fractures treated with a locking plate

Background

Management of distal femur fractures can be challenging, particularly in the aged female population. This retrospective study aims to analyze the surgical outcomes of aged female patients with non-periprosthetic distal femur fractures treated with a locking plate.

Methods

This is an IRB approved retrospective review conducted at a level 1 trauma center. Fifty-five female patients (mean age of 71 years) with non-periprosthetic distal femur fractures underwent open reduction internal fixation using a locking plate from 2005 to 2019. The average follow-up time was 67 weeks from the date of injury. Criteria used for diagnosis of nonunion included one or more of the following: (I) three consecutive months without progression of healing on postoperative radiographs, (II) a total of nine months postoperative without complete healing, or (III) the physician diagnosed nonunion using clinical judgement. Outcome data was analyzed and compared amongst patients with and without obesity or diabetes. Statistical analysis was performed utilizing Microsoft Excel 2022 Data Analysis ToolPak with a standard statistically significant P value of <0.05.

Results

Thirty-two patients (58%) with distal femur fractures achieved union after initial treatment while 23 patients (42%) were diagnosed with nonunion. Fourteen patients (61%) underwent revision with 9 of these patients (64%) achieving union while 5 patients (36%) had persistent nonunion. Average healing time from initial treatment to union was 29 weeks, while average time from definitive treatment to union was 22 weeks. Obese patients [body mass index (BMI) >30 kg/m2] had a nonunion rate of 65%, while non-obese patients had a nonunion rate of 28%. Patients with diabetes had a nonunion rate of 65%, while patients without diabetes had a nonunion rate of 28%.

Conclusions

Union can be successfully achieved in aged female patients with distal femur fractures treated with locking plates; however, the risks for nonunion and revision remain high. Patients with obesity and diabetes appear to be at an increased risk of nonunion (P=0.008 and 0.008, respectively). However, further research should be conducted with a prospective study or multivariate analysis and increased number of patients to reaffirm this data.

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

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

A comparison of osteoarticular allografts and allograft-prosthesis composites for reconstruction of the distal femur after resection of a bone tumour in childhood : a retrospective study

AIMS

Osteoarticular reconstruction of the distal femur in childhood has the advantage of preserving the tibial physis. However, due to the small size of the distal femur, matching the host bone with an osteoarticular allograft is challenging. In this study, we compared the outcomes and complications of a resurfaced allograft-prosthesis composite (rAPC) with those of an osteoarticular allograft to reconstruct the distal femur in children.

METHODS

A retrospective analysis of 33 skeletally immature children with a malignant tumour of the distal femur, who underwent resection and reconstruction with a rAPC (n = 15) or osteoarticular allograft (n = 18), was conducted. The median age of the patients was ten years (interquartile range (IQR) 9 to 11) in the osteoarticular allograft group and nine years (IQR 8 to 10) in the rAPC group (p = 0.781). The median follow-up of the patients was seven years (IQR 4 to 8) in the osteoarticular allograft group and six years (IQR 3 to 7) in the rAPC group (p = 0.483). Limb function was evaluated using the Musculoskeletal Tumor Society (MSTS) score.

RESULTS

At final follow-up, the knee was unstable in 9/18 patients (50%) in the osteoarticular allograft group and 2/15 patients (13%) in the rAPC group (p = 0.026). The median range of motion (ROM) of the knee was 117° (IQR 115° to 120°) in the osteoarticular allograft group and 100° (IQR 95° to 105°) in the rAPC group (p < 0.001). The median MSTS score was 25 (IQR 23 to 26) in the osteoarticular allograft group and 28 (IQR 26 to 29) in the rAPC group (p = 0.007). Osteoarthritic change was detected in 11/18 patients (61%) in the osteoarticular allograft group and in 4/15 (26%) patients in the rAPC group (p = 0.048).

CONCLUSION

In our series, a resurfaced allograft-prosthesis composite provided better knee stability and function, with a lower rate of osteoarthritis; an osteoarticular allograft was associated with better knee ROM.Cite this article: Bone Joint J 2022;104-B(10):1174-1179.

A Rare Case of Distal Femur Physeal Fracture Dislocation with Positional Vascular Compromise in an Adolescent Male

Introduction

Physeal fractures are a rare entity to occur around the knee. However, they may prove to be dangerous when encountered due to their proximity to the popliteal artery and associated risk of premature physeal closure. A distal femur displaced, SH type I, physeal fracture is very uncommon and is most likely caused by high velocity trauma.

Case Report

Here is a case of right sided distal femur physeal fracture dislocation in a 15-year-old boy having positional vascular compromise (popliteal vessel involvement) as a result of the fracture displacement. He was immediately planned for open reduction and fixation using multiple K wires due to limb threatening condition. We focus on the potential immediate and remote complications, the treatment modality and the functional outcome of the fracture.

Conclusion

Due to the potential risk of immediate limb-threatening complication due to vascular compromise, this kind of injury needs emergency fixation. Furthermore, long-term complications like growth disturbances have to be considered and prevented by early definitive treatment.

Three-dimensional fracture mapping and analysis of coronal fractures in AO/OTA types 33-B3 and C3

Background

Although the relatively high incidence of coronal fractures in the supracondylar–intercondylar fractures is well established, little is currently known about the morphology of those fractures. Herein, we characterized the coronal fractures in AO/OTA type 33-C3 and assessed their differences with Busch–Hoffa fractures (33-B3).

Methods

We retrospectively collected 61 cases of AO/OTA type 33-B or C fractures with coronal plane fragments and generated three-dimensional fracture maps of those with coronal fractures based on CT imaging and measured angle α (the angle between the coronal fracture and the posterior condyle axis in the axis plane) and angle β (the angle between the coronal fracture and the posterior femoral cortex in the sagittal plane).

Results

Thirty-three cases (32%) of AO/OTA type 33-C fractures contained coronal fragments. Most of them were type 33-C3 fractures. Angles α and β for type 33-C3 were significantly smaller than for type B3 at the lateral condyle, while the angles at the medial condyle were not significantly different. The fracture maps showed that the coronal fractures and the articular comminution area were more anterior in type 33-C3.

Conclusions

The incidence of coronal fractures was 32% and 67% in AO/OTA types 33-C and 33-C3, respectively. Our findings suggest that coronal fractures differed between both types, emphasizing the potential need for different treatment approaches.

Cementless curved endoprosthesis stem for distal femoral reconstruction in a Chinese population: a combined anatomical & biomechanical study

Background

The endoprosthetic knee reconstruction using a current universal femoral stem might not be suitable for local population due to the anatomical difference between Chinese and Western populations. We measured the anatomical parameters of Chinese femurs as reference for stem design, and proposed a cementless, curved, short endoprosthesis stem for the reconstruction of distal femur. This study analyzed the biomechanical performance of the newly designed stem aimed at the identification of better operative strategy.

Methods

The CT–scanning data of femurs derived from 96 healthy Chinese volunteers were imported into the Mimics software, and a segmental measurement strategy was applied to evaluate the radius of curvature (ROC) of the femoral medullary cavity. Then, 4 kinds of endoprosthetic replacement models were created based on the measurement results. Model A: the distal tumor resected femora + straight stem A; Model B: the distal tumor resected femora + curved stem B; Model C: the distal tumor resected femora + curved stem C; Model D: the distal tumor resected femora + curved stem D. Finally, the mechanical difference among these models were compared by finite element analysis.

Results

The mean femoral ROC of Segment_{1, 2, 3, 4, 5} measured in the present study was 724.5 mm, 747.5 mm, 1016.5 mm, 1286.5 mm, and 1128 mm, respectively. Based on the femoral ROC of Segment_2, the stem ROC of the curved stem B, C, and D was designed as 475 mm, 700 mm, and 1300 mm, respectively. Generally, all endoprosthetic replacement models showed a normal–like stress distribution on the femurs. However, compared to the straight stem, the biomimetic curved stem showed better biomechanical performance both in terms of reducing the extent of the stress shielding of the femur and in terms of minimizing the stress distribution of the implant.

Conclusions

The uncemented, curved, short stem with suitable ROC can perfectly match the Chinese femoral canal morphology which has better mechanical properties than the conventional femoral stem. Thus, this newly designed femoral stem might be an optimized method for treatment of malignant femoral tumours in the Chinese populations in the case that the numerical results are supported by future experimental studies.

Scattering and clustering the proximal screw construct in unilateral locking plate osteosynthesis of distal femoral fractures

INTRODUCTION

The importance of fixation construct in locking compression plate (LCP) is not well enlightened until recently. The aim of this study was to investigate radiological and clinical outcomes of scattering and clustering of the proximal screw fixation construct in unilateral LCP treatment of the distal femoral fractures.

MATERIALS AND METHODS

Patients who were treated for distal femoral fractures using unilateral LCP between January 2014 and December 2019 in our institute were included in this retrospective study. They were divided into groups 1 (35 cases, scattered proximal screw fixation) and 2 (35 cases, clustered proximal screw fixation). Mean follow-up period was 23.6 months for group 1 and 21.3 months for group 2. Medical history, patient demographics, injury characteristics, and surgical characteristics were reviewed and analyzed. Radiological findings including time to callus formation, bridging callus formation, union, and symmetry of the union were assessed and compared between the groups. Clinical outcomes included total blood loss during the operation, postoperative range of motion, and number of revision surgery.

RESULTS

The time for callus formation (5.8 weeks in group 1 vs. 4.1 weeks in group 2, p = 0.009) and bridging callus formation (12.5 weeks in group 1 vs. 10.7 weeks in group 2, p = 0.009) was significantly earlier in group 2. Despite similar union rates between groups, the mean time for radiological union was longer in group 2 (10.7 vs 7.4 months, p = 0.001). Though statistically insignificant, more asymmetric union was observed in group 2 (17 vs 11 cases).

CONCLUSIONS

Despite a delay in initial callus and bridging callus formation, scattering the proximal screws was better in achieving earlier and more balanced radiographic union than the clustered fixation. We recommend to avoid bridging more than five holes in the whole plate fixation construct to lessen the asymmetric callus formation and to prevent eventual plate breakage.

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

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

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

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

Radiographic Assessment of Aseptic Loosening of Tumor-Type Knee Prosthesis in Distal Femur

OBJECTIVE

To measure the full-length anteroposterior and lateral radiographs of lower limbs after the resection of a tumor in the distal femur and tumor-type knee prosthesis replacement and to analyze the factors leading to aseptic loosening of the prosthesis.

METHODS

A total of 26 cases of tumor-type knee prosthesis replacement or revision due to the distal femoral tumor at our hospital from January 2007 to December 2019 were retrospectively analyzed. The patients were divided into the loosening and unloosening groups depending on whether aseptic loosening occurred after surgery. Full-length anteroposterior and lateral radiographs of lower limbs were used to measure bone resection length, length of prosthesis, distance of proximal apex of the medullary stem of the femoral prosthesis from the maximum arc of the anterior femoral arch, diameter of the medullary stem, etc. Data were analyzed, and the risk factors for aseptic loosening of the prosthesis were explored.

RESULTS

The ratio of the prosthetic length to the femoral length (63.72 ± 5.21) and the ratio of the femoral medullary stem diameter to the femoral diameter (26.03 ± 8.45) were smaller in the loosening group than in the unloosening group. The difference was statistically significant (p < 0.05). The distance between the apex of the medullary stem and the maximum arc of the anterior femoral arch was significantly shorter in the loosening group (3.47 ± 2.96) than in the unloosening group, and the difference was statistically significant (p < 0.05). The measurement of the lower limb alignment showed significant differences between the loosening and unloosening groups in terms of HKAA, mLDFA, and distance between the lower limb alignment and the center of the knee joint (p < 0.05). The logistic regression analysis showed that less than 30% ratio between the medullary stem diameter and the femoral diameter, less than 3 cm distance between the apex of the medullary stem and the maximum curvature of the anterior arch of the femur, distance between the lower limb alignment and the center of the knee joint, and presence of varus knee and valgus knee after the surgery were the risk factors for aseptic loosening of the prosthesis.

CONCLUSIONS

The diameter of the femoral medullary stem of the prosthesis, the apex position of the prosthetic stem, and the lower limb alignment are the risk factors for aseptic loosening of the prosthesis.

A novel approach to distal femur: a minimally invasive technique for supracondylar and intercondylar fracture

Background

For treating distal femur fractures, minimally invasive plating techniques with indirect reduction of the metadiaphysis while minimizing the damage to the peripheral soft tissue has gradually become the standard. However, all the current approaches use a straight or lazy curved incision adjacent to the patella or along the lateral side of the femur, which allows for easier proximal extension but increases the incision length.

Methods

In order to achieve a more physiological and esthetic outcome while leaving the metadiaphysis untouched, we developed an approach using a lambda-shaped incision, which sacrifices the potential for proximal extension but preserves much more peripheral soft tissue. Here, we describe our technique and our experience with it in 19 patients (12 men and 7 women).

Results

Fractures healing by first intention was observed in all patients. The postoperative knee range of motion can reach up to 90° in most of the patient. Clinically, 9 patients had excellent results, 6 had good results, 3 had fair results, and 2 had loss of follow-up.

Conclusions

Our minimally invasive lambda-incision approach allows sufficient visual access to almost the entire joint surface, including the entire lateral femoral condyle, trochlear surface, and distal medial condyle, where reduction is required. The lambda incision provides a much larger window than that offered by a same-length straight incision. The vertical turn at the mid-patellar level parallels the skin crease and geniculate artery, reducing soft tissue damage and resulting in a smooth healing wound. Moreover, plate and distal screw insertion is easier than that through a straight incision. Because the metadiaphysis region is mostly left untouched, ideal fracture-healing environment is preserved.

Using Blumensaat's line to determine the sagittal alignment of the distal femur

BACKGROUND

A coherent measurement approach for sagittal alignment of the distal femur after fracture reduction or distal femur osteotomies is not available. The present study aims to introduce a new method using Blumensaat's line and tangent lines to the femoral cortexes to determine the sagittal alignment of the distal femur.

METHODS

113 patients who had true lateral knee radiographs were included. All of the radiographs were evaluated by one fellowship-trained knee surgeon and one radiologist using the PACS system. The Blumensaat's line was determined on the true lateral knee radiographs. Then, three long lines were drawn on the distal third of the femoral shaft. The first line is tangent to the anterior cortex of the femur, the second line is along with the anatomical axis of the femur, and the third line is tangent to the posterior cortex of the femur. The angles between Blumensaat's line and these lines were measured. Intraclass Correlation Coefficient (ICC) was used to measure the strength of inter-and intra-rater agreement.

RESULTS

The mean angle between the Blumensaat's line and the anatomical axis of the femur was 35.4 ± 3°. The mean angle between the Blumensaat's line and the line tangent to the anterior femoral cortex and the line tangent to the posterior femoral cortex were 34.5 ± 3° and 35.2 ± 3°, respectively. Excellent inter-and intra-rater reliabilities were observed between the measurements (ICC = 0.96 and ICC = 0.98, respectively). The angle between the Blumensaat's line and the line tangent to the posterior femoral cortex was significantly higher in participants aged < 38 years (p = 0.049). No other significant association was found between the angles and demographic characteristics of the patients.

CONCLUSIONS

The expected mean angles between the Blumensaat's line and the distal femur were 34.3 to 35.4 degrees. This finding could be useful to determine the normal sagittal alignment of the distal femur.

LEVEL OF EVIDENCE

II.

A biomechanical comparison between cement packing combined with extra fixation and three-dimensional printed strut-type prosthetic reconstruction for giant cell tumor of bone in distal femur

BACKGROUND

The most common reconstruction method for bone defects caused by giant cell tumor of bone (GCTB) is cement packing combined with subchondral bone grafting and extra fixation. However, this method has several limitations involving bone cement and bone graft, which may lead to poor prognosis and joint function. A titanium-based 3D-printed strut-type prosthesis, featured with excellent biocompatibility and osseointegration ability, was developed for this bone defect in our institution. The goal of this study is to comparatively analyze the biomechanical performance of reconstruction methods aimed at the identification of better operative strategy.

METHODS

Four different 3D finite element models were created. Model #1: Normal femur; Model #2: Femur with tumorous cavity bone defects in the distal femur; Model #3: Cavity bone defects reconstructed by cement packing combined with subchondral bone grafting and extra fixation; Model #4: Cavity bone defects reconstructed by 3D-printed strut-type prosthesis combined with subchondral bone grafting. The femoral muscle multiple forces were applied to analyze the mechanical difference among these models by finite element analysis.

RESULTS

Optimal stress and displacement distribution were observed in the normal femur. Both reconstruction methods could provide good initial stability and mechanical support. Stress distributed unevenly on the femur repaired by cement packing combined with subchondral bone grafting and extra fixation, and obvious stress concentration was found around the articular surface of this femur. However, the femur repaired by 3D-printed strut-type prosthetic reconstruction showed better performance both in displacement and stress distribution, particularly in terms of the protection of articular surface and subchondral bone.

CONCLUSIONS

3D-printed strut-type prosthesis is outstanding in precise shape matching and better osseointegration. Compared to cement packing and extra fixation, it can provide the almost same support and fixation stiffness, but better biomechanical performance and protection of subchondral bone and articular cartilage. Therefore, 3D-printed strut-type prosthetic reconstruction combined with subchondral bone grafting may be evaluated as an alternative for the treatment of GCTBs in distal femur.

Survivorship, complications, and outcomes following distal femoral arthroplasty for non-neoplastic indications

Aims

Endoprosthetic reconstruction with a distal femoral arthroplasty (DFA) can be used to treat distal femoral bone loss from oncological and non-oncological causes. This study reports the short-term implant survivorship, complications, and risk factors for patients who underwent DFA for non-neoplastic indications.

Methods

We performed a retrospective review of 75 patients from a single institution who underwent DFA for non-neoplastic indications, including aseptic loosening or mechanical failure of a previous prosthesis (n = 25), periprosthetic joint infection (PJI) (n = 23), and native or periprosthetic distal femur fracture or nonunion (n = 27). Patients with less than 24 months’ follow-up were excluded. We collected patient demographic data, complications, and reoperations. Reoperation for implant failure was used to calculate implant survivorship.

Results

Overall one- and five-year implant survivorship was 87% and 76%, respectively. By indication for DFA, mechanical failure had one- and five-year implant survivorship of 92% and 68%, PJI of 91% and 72%, and distal femur fracture/nonunion of 78% and 70% (p = 0.618). A total of 37 patients (49%) experienced complications and 27 patients (36%) required one or more reoperation. PJI (n = 16, 21%), aseptic loosening (n = 9, 12%), and wound complications (n = 8, 11%) were the most common complications. Component revision (n = 10, 13.3%) and single-stage exchange for PJI (n = 9, 12.0 %) were the most common reoperations. Only younger age was significantly associated with increased complications (mean 67 years (SD 9.1)) with complication vs 71 years (SD 9.9) without complication; p = 0.048).

Conclusion

DFA is a viable option for distal femoral bone loss from a range of non-oncological causes, demonstrating acceptable short-term survivorship but with high overall complication rates.

Cite this article: Bone Jt Open 2022;3(3):173–181.

An automatic measurement system of distal femur morphological parameters using 3D slicer software

In the field of joint surgery, the computer-aided design of knee prostheses suitable for the Chinese population requires a large quantity of anatomical knee data. In this study, we propose a new method that uses 3D Slicer software to automatically measure the morphological parameters of the distal femur. First, 141 femur samples were segmented from CT data to establish the femoral shape library. Next, balanced iterative reducing and clustering using hierarchies (BIRCH) combined with iterative closest point (ICP) and generalised procrustes analysis (GPA) were used to achieve fast registration of the femur samples. The statistical model was automatically calculated from the registered femur samples, and an orthopaedic surgeon marked the points on the statistical model. Finally, we developed an automatic measurement system using 3D Slicer software, and a deformable model matching method was applied to establish the point correspondence between the statistical model and the other samples. By matching points on the statistical model to corresponding points in other samples, we measured all other samples. We marked six points and measured eight parameters. We evaluated the performance of automatic matching by comparing the points marked manually with those matched automatically and verified the accuracy of the system by comparing the manual and automatic measurement results. The results indicated that the average error of the automatic matching points was 1.03 mm, and the average length error and average angle error measured automatically by the system were 0.37 mm and 0.63°, respectively. These errors were smaller than the intra-rater and inter-rater errors measured manually by two different surgeons, which showed that the accuracy of our automatic method was high. Taken together, this study established an accurate and automatic measurement system for the distal femur based on the secondary development of 3D Slicer software to assist orthopaedic surgeons in completing the measurements of big data and further promote the improved design of Chinese-specific knee prostheses.

A novel radiological classification system of the distal femur

INTRODUCTION

In our previous studies, we were able to identify anatomical differences as a predictor for aseptic loosening following primary and revision surgery with the use of rotating hinge prosthesis. This study was performed to answer following question: can a novel radiological classification system of the distal femur be identified?

MATERIALS AND METHODS

A total of 200 patients who received standardized anteroposterior (AP) and lateral views of the knee joint were included in this study. On AP radiographs, we measured the distance between inner diameter of the femur at 20 cm proximally from the knee and at a point 2 cm proximally from the adductor tubercle. The ratio of the inner diameter of the femoral canal at 20 cm proximal of knee joint to the inner diameter of medullary canal at 2 cm proximal of adductor tubercle was used as a novel index ratio. Two observers blindly and independently reviewed the anteroposterior radiographs twice.

RESULTS

Three groups of anatomical classification can be constructed for each sex according to the 25th and 75th percentiles. A higher distribution of Type C was found in female patients. The median intra-observer reliability for rater 1 was 0.995 (IQR 0.994-0.997). We had also a high inter-observer reliability with ICC of 0.997 (95% CI 0.996-0.998).

CONCLUSIONS

The novel classification presents three different types of the knee joint for male and female patients. Type C has a wider inner diaphyseal diameter compared to Type A with a narrow inner diaphyseal diameter.

Locked Plating Versus Retrograde Intramedullary Nailing for Distal Femur Fractures: a Systematic Review and Meta-Analysis

Modern advances in techniques and implants have allowed for a better operative fixation for distal femoral fractures. Both locked plating and retromedullary nail have allowed surgeons to stabilize these fractures with minimal soft tissue dissection and preserve blood supply. Although both the implants have been used extensively for such types of fractures, the superiority of one implant over the other is still doubtful. Therefore, we conducted this meta-analysis to compare locked plating and retrograde intramedullary nailing in distal femoral fractures. Based on prisma guidelines, electronic databases, including PubMed, Embase, Scopus, and Ovid Medline were searched using a well-defined search strategy. Outcome measures which were studied included blood loss, implant failure, infection, knee range of motion, malunion, non-union, pain, surgical duration and union time Surgical duration (95% CI 2.90 to 17.13, p <0.01) and blood loss (95% CI 69.60 to123.18, p <0.01) favoured plating group and the difference is significant. But while analysing parameters like implant failure, knee range of motion, non-union and union time, our analysis favoured nailing group, but the difference is not significant. Overall, both locked plating and retrograde intramedullary nailing are comparable with respect to union and complications in distal femur fractures, but we need further larger and high quality randomized studies to evaluate the difference.

Outcomes of Primary Total Knee Arthroplasty in Fractures Around the Knee in the Elderly: A Systematic Review and Pooled Analysis of 212 Patients Across 11 Studies

BACKGROUND

Treatment of fractures around the knee in the elderly is somewhat controversial with primary total knee arthroplasty (TKA) gaining prominence over the past decade or so, as an alternative for open reduction and internal fixation. The present review was conceptualized to review the published literature and evaluate outcomes of TKA in these patients, and to understand whether this is a viable treatment option for these fractures. We have further tried to identify complications and the challenges faced while performing this surgery.

METHODS

PRISMA guidelines were followed and search was conducted on three databases-PubMed, EMBASE and SCOPUS. Studies evaluating multiple factors related to outcomes and complications in primary TKA performed for fractures around the knee in the elderly were included. Cadaveric studies, conference abstracts, case reports, and any studies that included non-traumatic cases or revision after failed internal fixation, were all excluded.

RESULTS

Eleven studies, published between 2011 and 2021 were included in our review. There was significant female preponderance in the study population (M:F = 1:3). Implants with higher constraint (high post, hinged prosthesis) were frequently required to compensate for ligamentous laxity due to the fractures. On pooled analysis the mean Knee Society Score (KSS) knee score was 84.62 (excellent), and mean knee range of motion was 107.25°. However, the mean KSS function score was 56.71 (poor), which could have been due to co-morbid conditions and pre-operative status. Overall complication rate was 14.6%; surgical site infection was the most commonly reported.

CONCLUSION

There remains limited evidence for the use of TKA as a primary treatment option for these injuries. In the presence of specific conditions, and in expert hands-it may be a viable alternative to osteosynthesis with comparable outcomes. More focused studies are needed to compare the two treatment options and to formulate guidelines.

Do the distal femur and the proximal tibia have narrower aspect ratios in smaller knees? : A morphological analysis of osteoarthritic knees in the Japanese population using computed tomography

BACKGROUND

Whether the distal femur and the proximal tibia have narrower aspect ratios in smaller knees has not been clarified. The purpose of this study was to confirm the dimensional characteristics of the distal femur and the proximal tibia using a novel method for consistently determining knee size.

METHODS

A total of 220 Japanese osteoarthritic knees (160 female and 60 male knees) were analyzed using computed tomography. The mediolateral (ML) and the anteroposterior (AP) dimensions of the distal femur (fML, fAP) and the proximal tibia (tML, tAP) were measured. The aspect ratios (ML/AP) of the distal femur (fML/fAP) and the proximal tibia (tML/tAP) were assessed against the product of AP × ML as a consistent determination of knee size.

RESULTS

The fML/fAP ratios positively correlated with knee size (fAP × fML) (r = 0.420, p < 0.001), only in the combined cohort, attributable to the narrower aspect ratios of female knees. No correlations were found between the tML/tAP ratios and knee size (tAP × tML) among females, males, nor all subjects (p = 0.299, 0.994, and 0.996, respectively). Aspect ratio correlations to knee size diverged between the three knee size indices, AP, ML, and AP × ML.

CONCLUSIONS

AP × ML was the meaningful option for knee size indexing in our morphological analyses. The distal femur, but not the proximal tibia, was found to have a narrower aspect ratio in female knees in the Japanese population.

Distal femur versus humeral or tibial IO, access in adult out of hospital cardiac resuscitation

BACKGROUND

Intraosseous (IO) vascular access is a well-established method for fluid and drug administration in the critically ill. The Food and Drug Administration has approved adult IO access at the proximal humerus, proximal tibia, and the sternum; all three sites have significant limitations. The Distal Femur is away from the chest, with high flow rates. The objective of this study was to evaluate the distal femur site during resuscitation of adult out-of-hospital cardiac arrest.

METHODS

A retrospective analysis of adult out of hospital cardiac arrest patients treated by the San Antonio Fire Department. IO access was obtained by first-responders (paramedics or EMT-basic) or EMS paramedics. All resuscitation attempts from 2017 to 2018 data were analyzed. The protocol did not dictate the preference of IO site. The primary measure: number of OHCA patients in each subgroup: IO femur, IO humerus, IO tibia. Secondary measures: paramedic or basic operator, dislodgement rate, and total fluid infused.

RESULTS

There were 2,198 patients meeting inclusion criteria: 888 femur, 696 humerus, 432 tibia. Distal femur increased 2.5 times in the 2018 cohort compared to the 2017 cohort, with a corresponding decrease in humerus (factor of 0.29). Proximal tibia remained unchanged. Dislodgement rates and total infusion (ml) remained unchanged.

CONCLUSIONS

The distal femur IO was feasible and associated with similar measured performance parameters as other IO sites in adult OHCA for both advanced and basic life support personnel.

Intercalary reconstruction of the distal femur with or without physeal preservation: results and impact on limb growth

PURPOSE

Allograft reconstruction with or without vascularized fibula can be a valuable solution to treat childhood intercalary tumours of the distal femur. We aimed to assess the oncological status, complication rate and survival of distal femur intercalary reconstruction after trans-metaphyseal (TMR) and trans-epiphyseal resection (TER). We also evaluated the impact of distal temporary graft fixation on skeletal growth after TMR.

METHODS

We retrospectively reviewed 23 skeletally immature patients affected by distal femur osteosarcoma (18) and Ewing sarcoma (5). Mean patients age was 10.3 years. In 11 cases, TMR was performed with physis preservation and temporary distal graft fixation. In 9 patients, TER was performed with growth plate sacrifice. The last 3 cases were treated with TMR and sliding plate fixation.

RESULTS

Mean follow-up was 8.4 years. No deaths occurred, but 3 patients presented lung metastasis and 2 cases presented local recurrence in soft tissues. 10 implant-related complications occurred, all surgically treated. At skeletal maturity, mean femoral dysmetria was 2.3 cm after TMR and temporary epiphysiodesis, and 3.1 cm after TER. In TMR group, a strong trend towards physeal recovery was observed after epiphyseal screws removal (p = 0.061), but valgus deformity in distal femur was more frequent (p = 0.049). MSTS score was good or excellent in all patients, with no statistically significant difference between TMR and TER.

CONCLUSIONS

Intercalary graft reconstruction after TMR and TER allows good local disease control and excellent functional results with long-term follow-up. Temporary distal fixation might reduce the final limb discrepancy after TMR, but valgus deformity could develop.

LEVEL OF EVIDENCE

Level IV.

New versus old: 95 degree angled blade plate versus distal femoral locking plate. A randomized clinical trial

INTRODUCTION

The purpose was to compare the locking condylar plate (LCP) with the 95° angled blade plate (ABP) for distal femoral fracture patterns amenable to either device. Our hypothesis was that LCP would outperform ABP with primary outcome of nonunion and secondary outcomes of reoperation and malunion.

METHODS

78 adult patients with 79 eligible fractures and mean age of 60 years were prospectively randomized to LCP (n = 45) or ABP (n = 34). Mean ISS was 16. 22% fractures were open. Patient-reported functional outcomes were assessed with the Musculoskeletal Function Assessment (MFA).

RESULTS

All patients were followed to union, and mean follow-up was 25 months. There were no differences in age, sex, fracture pattern, co-morbidities or mechanism for the two groups. Three patients had infections, one superficial after LCP and one deep infection each after ABP and LCP. Three patients developed nonunion after LCP versus none after ABP (p = 0.06). Nine patients healed with minor deformity after LCP versus 5 following ABP. One fracture had major deformity after ABP versus two after LCP. Eight patients had a secondary procedure following LCP versus two after ABP (p = 0.05).

CONCLUSIONS

The investigation failed to support newer technology being better. Evidence did not indicate the LCP was superior to the ABP. Trends for primary union and fewer secondary procedures suggest that ABP may have superior performance to LCP for fracture patterns which may be treated with either implant.

Three-dimensional morphology of the distal femur based on surgical epicondylar axis in the normal elderly population

BACKGROUND

We aimed to analyze the surface morphology of the distal femur in three dimensions for the healthy elderly, based on the concept that the surgical epicondylar axis (SEA) is a better surrogate for the flexion-extension axis of the knee joint.

METHODS

We studied 77 healthy elderly volunteers (40 males and 37 females; age, 68 ± 6 years). The medial and lateral contact lines were calculated three-dimensionally, using the highest points of the medial and lateral condyles in 201 cross-sectional planes around the SEA (every 1°, -60° (hyperextension) to 140° (flexion)). A piecewise fitting function consisting of two linear segments was applied to detect the inflection point of the constant radii in the sagittal plane. The main assessment parameters were knee flexion angle at the inflection point of the radius (inflection angle), mean radius from 0° to the inflection angle (constant radius), and coronal tilt angle of the contact line.

RESULTS

The inflection angles, constant radii, and coronal tilt angles were 78.2 ± 8.6°, 26.1 ± 2.3 mm, and -0.6 ± 3.2° and 65.6 ± 9.2°, 23.9 ± 2.2 mm, and 6.2 ± 3.2° in the medial and lateral condyles, respectively (all, P < 0.001). The coronal alignment was 88.7 ± 2.2°.

CONCLUSIONS

The medial and lateral femoral condyles showed asymmetrical morphologies with the almost 'constant' radius of sagittal curvature from 0° to around 80° and 65° of knee flexion, respectively.

Comparison of three methods of Müller type C2 and C3 distal femoral fracture repair

Background

We compared the outcomes of three fixation techniques for Müller type C2 and C3 distal femoral fractures.

Methods

We retrospectively analyzed patients undergoing internal fixation for Müller type C2 and C3 distal femoral fractures via locking plate (Group A), lateral locking condylar plate and medial contoured reconstruction plate (Group B), and lateral locking condylar plate and anterior reconstruction plate (Group C). Knee joint functional recovery and functional outcomes were evaluated 12 months postoperatively.

Results

Patients included 34 men and 24 women aged 25 to 74 years (mean, 50.3 ± 10.73 years). Operating times were longest in Group B and similar in Groups A and C. Bleeding volume in Group A was smaller than in Group B and similar to that of Group C. Functional outcomes were excellent in 18 (31%) fractures, good in 24 (41%), moderate in 11 (19%), and poor in 5 (9%). Good-to-excellent results were achieved in 56%, 82%, and 83% of patients (Groups A, B, and C, respectively). Groups B and C's outcomes were superior to Group A's outcomes. No significant difference in postoperative complications between the groups existed.

Conclusion

Lateral locking condylar and anterior reconstruction plating was useful for complex type C distal femoral fractures.

Long-term outcomes and improved risk of revision following tumor endoprosthetic replacement of the distal femur: Single institutional results

Purpose

This study assessed revision characteristics following distal femur tumor endoprosthetic replacement.

Methods

Fifty-seven procedures were performed between 2005 and 2019. The cumulative incidence of implant revision was calculated with death as a competing risk.

Results

The all-cause revision rate was 21.1% (n = 12) at a mean 65.3 ± 47.3 months. Competing risk analysis revealed a cumulative revision incidence of 12.0% (95% CI, 3.6-25.9%) at five years and 36.5% (95% CI, 12.8-61.0%) at ten years.

Conclusions

We provide an accurate assessment of revision risk which is slightly lower than historical controls, with identification of failure modes to reliably inform patient expectations.

Level of evidence

III. Retrospective Study.

Resurfaced allograft-prosthetic composite for distal femur reconstruction in children with bone tumor

INTRODUCTION

Reconstruction of the distal femur in children following resection of bone sarcoma is challenging. The main problem in children is the small size of bone and a possible limb-length discrepancy at the end of skeletal growth secondary to the loss of the physes. We reported the results of a new surgical technique for distal femur reconstruction after bone tumor resection in children.

MATERIAL AND METHODS

We analyzed 5 patients with distal femoral sarcomas who underwent intra-articular resection and reconstruction with resurfaced allograft-prosthetic composite at a mean follow-up of 70 months. There were 2 males and 3 females, with a mean age of 10 years (range 8-12) at the time of the diagnosis. All patients were affected by high-grade osteosarcoma. The patients' medical records were reviewed for clinical and functional outcomes as well as post-operative complications. The functional evaluation of the patients was done at the end of the follow-up using Musculoskeletal Tumor Society scoring system. The minimal follow-up was 24 months.

RESULTS

At the last follow-up, 4 patients were continuously disease-free. We excluded one patient who died of disease secondary to lung metastases 16 months after the surgery. Complications occurred in 2 of 4 patients at 17 months and 24 months, respectively. One patient developed deep infection who required the removal of the original reconstruction and, once the infection was treated, the patient underwent reconstruction with an expandable prosthesis. An allograft fracture occurred in another of the 4 patients at 24 months after the first surgery, thus the original reconstruction was removed and the patient underwent reconstruction with modular prosthesis. In the two patients who retained the original reconstruction at the time of their latest follow-up, the mean implant survival time was 70 months. These patients had an excellent MSTS score (29.5 points) and walked without support or limitations with an active knee range of motion of > 90° and complete active extension of the knee. No degenerative changes of the articular surface of the proximal tibia and the patella were observed at the time of the last follow-up. Growth of the physis of the proximal tibia was observed in all the patients during follow-up and no angular deformity of the joint was observed. The limb discrepancy was 4 cm and 2 cm, respectively.

CONCLUSIONS

Resurfaced allograft-prosthetic composite may represent an alternative surgical technique for distal femur reconstruction in children with bone sarcomas. Although its success is limited by high risk of complications, resurfaced allograft-prosthetic composite seems to be a viable option to preserve the bone stock and the physis of the proximal tibia in selected young patients, minimizing a potential limb-length discrepancy at the end of the skeletal growth.