Distal Femoral Condyle Research Articles

The effect of obesity on the anatomical relationship of the popliteal artery and tibial nerve in the proximal and distal popliteal fossa: relevance to popliteal sciatic nerve block and a traceback technique using the popliteal artery

Study ObjectiveTo determine the effect of body mass index (BMI) on the relationship of the popliteal artery to the sciatic and tibial nerves in the popliteal fossa. DesignProspective, observational study. SettingUniversity medical center. SubjectsOne hundred patients scheduled for magnetic resonance imaging scans of the knee. MeasurementsBMI was recorded and magnetic resonance imaging scans were assessed at 3 different measurement points along the femur for the distance and angle between the popliteal artery and tibial nerve, or sciatic nerve if the sciatic nerve had not bifurcated at the measurement point. Main ResultsAt the distal femur, the tibial nerve was a mean of 2.9 mm from the popliteal artery. The nerve was consistently posterior to the artery; however, it was variably located medial or lateral to the artery. At the 5- and 8-cm measurement points, the nerve was 10.0 and 16.1 mm (SD, 4.1 and 5.2 mm), and 31° and 44° (SD, 15° and 16°) lateral to the popliteal artery, respectively. Zero degree was defined as directly posterior to the artery. Increasing BMI was correlated with increasing distance between the nerve and the artery at the 5- and 8-cm measurement points (r= 0.36 P> |t| .000 and .45 P> |t| .002). ConclusionsAt 5 cm proximal to the distal femoral condyles, the popliteal artery is a reliable sonographic landmark to locate the tibial nerve due to the close proximity and consistent location of the nerve 1 cm posterolateral to the artery, with only a moderate effect of BMI.

Femoral footprint of the popliteus tendon may be at the risk of damage during total knee arthroplasty.

The present study focused on the prevalence of incidental excision of the femoral footprint of the popliteus tendon during total knee arthroplasty and its associated risk factors. A total of 275 knee arthroplasties were performed for 226 patients with varus knee osteoarthritis. The status of the femoral footprint of the popliteus tendon was intraoperatively evaluated and classified into three groups (preserved, partially excised, and completely excised), and the prevalence of the excision was identified. Femoral component size, the thickness of the resected distal femoral condyle, and preoperative patient demographic data were compared for the three groups. Ordinal logistic regression analysis was performed to reveal risk factors associated with the excision. The femoral footprint of the popliteus tendon was preserved in 132 knees (48.0%), partially excised in 94 knees (34.2%) and completely excised in 49 knees (17.8%). The ordinal logistic regression analysis revealed thicker resection of the distal femoral condyle (p<0.0001) and shorter body height (p=0.0266) to be the independent risk factors for the excision. The incidental partial or complete excision of the femoral footprint of the popliteus tendon was identified in approximately half of the evaluated knees. Thicker resection of the distal femoral condyle and shorter body height were the most significant risk factors for the excision. Case-control study, Level III.

Anatomical landmarks of the distal femoral condyles are not always parallel to the tibial bone cut surface in flexion during total knee arthroplasty

BackgroundSoft tissue balancing is crucial to the success of total knee arthroplasty (TKA). To create a rectangular flexion joint gap, the rotation of the femoral component is important. The purpose of this study is to determine whether or not anatomical landmarks of the distal femoral condyles are parallel to the tibial bone cut surface in flexion. MethodsForty-eight patients (three male and 45 female) with a mean age of 74years were examined. During the operation, we estimated the flexion joint gap with the following three techniques. 1) a three degree external cut to the posterior condylar line (MR1), 2) a parallel cut to the surgical transepicondylar axis (MR2), and 3) a parallel cut to the anatomical transepicondylar axis (MR3). ResultsThe flexion joint gap was 1.1±3.0° (mean±standard deviation (SD)) in internal rotation in the case of MR1, 0.9±3.4° in internal rotation in the case of MR2, and 2.1±3.4° in external rotation in the case of MR3. An outlier (flexion joint gap >3.0°) was observed in 12 cases (25%) in MR1, 13 cases (27%) in MR2, and 15 cases (31%) in MR3. ConclusionsThe anatomical landmarks of the distal femoral condyles are not always parallel to the tibial bone cut surface in flexion. To create a rectangular flexion joint gap, the rotation of the femoral component rotation is based not only on the anatomical landmarks but also on the ligament balance.

Brodie’s abscess of medial distal femoral condyle after a thorn prick: rare clinical presentation

AbstractThorn prick injuries are generally conceded frivolous and rarely demand medical attention. How-beit deep seated injuries are well described in the literature. We presented a case of thorn prick injury to the knee that manifested as Brodie’s abscess of the medial distal femoral condyle and synovitis. Magnetic resonance imaging (MRI) and ultrasonography could only construe the affliction but not spot the thorn. Arthrotomy was undertaken for exploration and debridement. Empirical therapy with initial systemic Cefotaxime and subsequent Ofloxacin worked well after the surgery. Deep seated injuries by a thorn prick may take a protracted and torpid course. Thorough curettage of the bony lesion and debridement are vital for proper management.

Effects of cisplatin chemotherapy on the osseointegration of titanium implants.

The effect of chemotherapy on the osseointegration of dental implants has received less interest compared with radiotherapy. Thus, the aim of the current study was to investigate the effect of cisplatin chemotherapy on the osseointegration of dental implants in a rabbit model. Sixteen New Zealand White rabbits were randomly assigned to two groups of treatment of either cisplatin at 2.5mg/kg/week for 4 weeks (n=8) or placebo (n=8), in which the first dose was administered 2 days prior to the surgical procedure. Each rabbit received one titanium dental implant inserted in the right distal femoral condyle. Four rabbits from each group were sacrificed 4 and 8 weeks after implant insertion. Osseointegration of the dental implants was analysed using micro-computed tomography and histomorphometric evaluation. Analysis of micro-computed tomography data and histomorphometric data showed that the osseointegration parameters, including the ratio of bone volume to total volume (BV/TV) and bone-implant contact (BIC%) for the cisplatin group, were significantly lower compared to the control group at 4 and 8 weeks. (P≤0.05). Cisplatin chemotherapy had a negative effect on the osseointegration of dental implants when inserted throughout the chemotherapeutic regimens in a rabbit model.

Influence of pore size of porous titanium fabricated by vacuum diffusion bonding of titanium meshes on cell penetration and bone ingrowth

The present work assesses the potential of three-dimensional (3D) porous titanium (pore size of 188–390μm and porosity of 70%) fabricated by vacuum diffusion bonding of titanium meshes for applications in bone engineering. Rat bone marrow mesenchymal stem cells were used to investigate the proliferation and differentiation of cells on titanium scaffolds with different pore sizes at day 7, day 14 and day 21 based on DNA contents, alkaline phosphatase (ALP) activity, collagen (COL) secretion and osteogenic gene expressions including ALP, COL-1, bone morphogenetic protein-2 (BMP-2), osteopontin (OPN), runt-related transcription factor 2 (RUNX2), using smooth solid titanium plate as reference material. The rabbit models with distal femoral condyles defect were used to investigate the bone ingrowth into the porous titanium. All samples were subjected to Micro-CT and histological analysis after 4 and 12weeks of healing. A one-way ANOVA followed by Tukey post hoc tests was used to analyze the data. It was found that the differentiation stage of cells on the porous titanium delayed compared with the smooth solid titanium plate and Ti 188 was more inclined to promote cell differentiation at the initial stage (day 14) while cell proliferation (day 1, 4, 7, 10, 14 and 21) and bone ingrowth (4 and 12weeks) were biased to Ti 313 and Ti 390. The study indicates that the hybrid porous implant design which combines the advantages of different pore sizes may be meaningful and promising for bone defect restoration. Statement of SignificanceOne of the significant challenges in bone defect restoration is the integration of biomaterials and surrounding bone tissue. Porous titanium may be a promising choice for bone ingrowth and mineralization with appropriate mechanical and biological properties. In this study, based on porous titanium fabricated by vacuum diffusion bonding of titanium meshes, we have evaluated the influence of various pore sizes on rat bone marrow mesenchymal stem cells (rBMMSCs) penetration in vitro and bone ingrowth in vivo. It was interesting that we found the proliferation and differentiation abilities of rBMMSCs, as well as bone ingrowth were related to different pore sizes of such porous scaffolds. The results may provide guidance for porous titanium design for bone defect restoration.

Improving the accuracy of wide resection of bone tumors and enhancing implant fit: A cadaveric study

Background/AimsCustomized three-dimensional (3-D) jigs have been shown to increase the accuracy of skeletal tumor resection in comparison to freehand techniques. However, the utility of these jigs in subsequently enhancing the fit of endoprosthetic implants has yet to be determined. We hypothesized that custom jigs would improve implant fit compared to freehand resection. MethodsNine matched pairs of cadaveric femurs were scanned by CT. The images then had ‘virtual’ tumors positioned on the distal medial femoral condyle and preoperative resection plans were generated. Custom implants were designed to fit into the resected spaces and 3-D printed. Similarly, customized 3-D jigs were designed and printed for half of the femurs. Resections were then performed using the jigs or freehand. The implants were positioned in the resected femurs and the accuracy-of-fit was quantitatively assessed by re-scanning the resected femurs and calculating the deviation from the implant (in degrees) for each of the 3 cutting planes. The results were then compared between jig and freehand resections. ResultsFor the first plane, the jig resulted in less deviation than the freehand cut, but it did not achieve statistical significance. However, for the 2nd and 3rd planes, the jigs deviated 1.78° and 2.20° from the implants compared to 4.41° and 7.96° for the freehand cuts, both of which were statistically significant improvements (p=0.038 and p=0.003). ConclusionIn summary, customized 3-D jigs were shown to improve the accuracy-of-fit between implants and host bone, moving this technology closer to clinical implementation.

Comparison of Osteochondral Autografts and Allografts for Treatment of Recurrent or Large Talar Osteochondral Lesions.

The purpose of this study was to prospectively evaluate and compare the long-term clinical and radiographic outcomes of using osteochondral autograft and allograft to manage either recurrent or large osteochondral lesions of the talar dome (OLT) in a single surgeon's practice. Between January 2008 and January 2014, a total of 40 patients presented with either a recurrent OLT that failed initial arthroscopic treatment (ie, excision, curettage, debridement, and micro-fracture) or a primary OLT greater than 1.5 cm2 that had undergone no prior surgery. Before surgery, 20 patients were randomized to receive osteochondral autograft plugs (Arthrex, Naples, FL) from the ipsilateral superolateral distal femoral condyle whereas the remaining 20 were randomized to receive osteochondral allograft plugs from a fresh size-matched donor talus (Joint Restoration Foundation, Centennial, CO, and Arthrex, Naples, FL), but 4 of these were excluded that received a hemi-talus allograft with internal fixation. Preoperative and postoperative function and pain was graded using the Foot and Ankle Ability Measures (FAAM) scoring system and a Visual Analog Scale (VAS) of pain, respectively. Radiographs were assessed for osteochondral graft healing, joint congruency, and degenerative changes. Data regarding postoperative complications and revision surgeries were also recorded. Of the 20 patients who received osteochondral autograft, the mean FAAM score increased from 54.4 preoperatively to 85.5 at the time of final follow-up. The mean VAS pain score decreased from 7.9 of 10 preoperatively to 2.2 of 10 at final follow-up. Two patients (10%) that received osteochondral autograft, 1 for a recurrent OLT of 1.3 cm2 and 1 for a primary OLT of 2.0 cm2, developed a symptomatic nonunion at the entire graft site. Both of these patients had their autograft converted to talar allograft plugs and achieved full osteochondral healing. At the time of final follow-up, no patients who received osteochondral autograft developed ankle degenerative changes or knee complications. The mean FAAM score of the 16 patients who received osteochondral allograft plugs increased from 55.2 preoperatively to 80.7 at the time of final follow-up. This postoperative score was lower than that of the osteochondral autograft group, but not to a statistically significant degree (P = .25). The mean VAS pain score decreased from 7.8 of 10 preoperatively to 2.7 of 10 at final follow-up. This postoperative score was higher than that of the osteochondral autograft group but not to a statistically significant degree (P = .15). Three patients (18.8%) that received osteochondral talar allograft, 2 for recurrent OLTs less than 1.5 cm2 and 1 for a primary OLT of 2.2 cm2, developed a symptomatic nonunion at the entire graft site. Two of these 3 patients had their allograft converted to osteochondral autograft plugs harvested from the ipsilateral superolateral distal femoral condyle and achieved full osteochondral healing. At the time of final follow-up, 1 of these 16 (6.3%) patients who received talar allograft as OLT treatment had developed asymptomatic anterior ankle arthritis upon radiographs. Using fresh talar osteochondral allograft provided results that were comparable to the use of distal femoral osteochondral autograft for treating recurrent or large OLTs. Although the use of allograft avoided the risk of knee complications when harvesting autograft from the distal femur, fresh talar allograft may have lower healing rates than osteochondral autograft. Level II, comparative case series.

Injectable Bone Substitute Based on β-TCP Combined With a Hyaluronan-Containing Hydrogel Contributes to Regeneration of a Critical Bone Size Defect Towards Restitutio ad Integrum.

In the present in vivo study, the regenerative potential of a new injectable bone substitute (IBS) composed of beta-tricalcium phosphate (β-TCP) and hyaluronan was tested in a rabbit distal femoral condyle model. To achieve this, 2 defects of 6 mm in diameter and 10 mm in length were drilled into each femur condyle in a total of 12 animals. For each animal, 1 hole was filled with the substitute material, and the other was left empty to serve as the control. After 1, 3, and 6 months, the regenerative process was analyzed by radiography as well as by histological and histomorphometrical analysis. The results revealed that bone tissue formation took place through osteoconductive processes over time, starting from the defect borders to the center. Both the β-TCP content and the hydrogel support bone tissue growth. The histomorphometrical measurements showed that the amount of bone formation in the experimental group was significantly higher compared with that found in the control group after 3 months (19.51 ± 5.08% vs. 1.96 ± 0.77%, P < .05) and 6 months (4.57 ± 1.56% vs. 0.23 ± 0.21%, P < .05). The application of the IBS gave a restitutio ad integrum result after 6 months and was associated with its nearly complete degradation, in contrast to the results found in the control group. In conclusion, the results of the present study demonstrate that the IBS contributes to sufficient bone regeneration by serving as a scaffold-like structure, combined with its degradation within 6 months.

3D Printable Biophotopolymers for in Vivo Bone Regeneration

The present study investigated two novel biophotopolymer classes that are chemically based on non-toxic poly (vinyl alcohol). These vinylesters and vinylcarbonates were compared to standard acrylates in vitro on MC3T3-E1 cells and in vivo in a small animal model. In vitro, both vinylester and vinylcarbonate monomers showed about tenfold less cytotoxicity when compared to acrylates (IC50: 2.922 mM and 2.392 mM vs. 0.201 mM) and at least threefold higher alkaline phosphatase activity (17.038 and 18.836 vs. 5.795, measured at [10 mM]). In vivo, polymerized 3D cellular structures were implanted into the distal femoral condyle of 16 New Zealand White Rabbits and were observed for periods from 4 to 12 weeks. New bone formation and bone to implant contact was evaluated by histomorphometry at end of observation. Vinylesters showed similar rates of new bone formation but significantly less (p = 0.002) bone to implant contact, when compared to acrylates. In contrast, the implantation of vinylcarbonate based biophotopolymers led to significantly higher rates of newly formed bone (p < 0.001) and bone to implant contact (p < 0.001). Additionally, distinct signs of polymer degradation could be observed in vinylesters and vinylcarbonates by histology. We conclude, that vinylesters and vinylcarbonates are promising new biophotopolymers, that outmatch available poly(lactic acid) and (meth)acrylate based materials.

Distal femoral condyle is more internally rotated to the patellar tendon at 90° of flexion in normal knees.

BackgroundThe configuration of the distal surface of the femur would be more important in terms of the patellofemoral (PF) joint contact because the patella generally contacts with the distal surface of the femur in knee flexion. Some total knee arthroplasty (TKA) designs configurate medially prominent asymmetric femoral condyles. This difference in the design of distal femoral condyle may affect the PF joint congruity in knee flexion. Furthermore, some surgeons advocate a concept aligning the symmetric components parallel to the native joint inclination, not perpendicular to the mechanical axis. This concept would also make a difference on the PF joint congruity at the distal femur in knee flexion. However, no fundamental study has been reported on the PF congruity at the distal femur to discuss the theoretical priority of these concepts.The current study investigated the angular relationship between the tibial attachment of the patellar tendon and the distal surface of the femur at 90° of flexion in normal knees.MethodsThe open magnetic resonance images of 45 normal knees at 90° of flexion were used to measure the angles between the tibial attachment of the patellar tendon, the equatorial line of the patella, and the distal surface of femoral condyles.ResultsThe distal surface of femoral condyles was internally rotated relative to the tibial attachment of the patellar tendon and the equatorial line of the patella in all the knees (8.2° ± 3.5° and 5.8° ± 2.5°, respectively), not parallel.ConclusionsDistal femoral condyle is internally rotated to the patellar tendon at 90° of flexion in normal knees. When the symmetric femoral component is aligned perpendicular to the femoral mechanical axis, the patellar tendon would be possibly more twisted than the condition in normal knees, and the deviation of the PF contact force on the patellar component might be caused. The configuration and alignment of the distal condyle of the femoral component can affect the PF joint congruity in knee flexion. In this respect, our results provide important information in considering designs and alignment in the distal femur of TKA and the PF joint congruity in knee flexion.

Topographic Analysis of the Capitellum and Distal Femoral Condyle: Finding the Best Match for Treating Osteochondral Defects of the Humeral Capitellum

The purpose of this study was to determine the donor zone of most congruent topographic match by comparing 4 donor sites from the femur with 4 potential recipient sites of osteochondritis dissecans at the capitellum. Computed tomography was performed on 5 right elbows and 6 right medial and 6 right lateral distal femoral hemicondyles, which included the femoral notch. Three-dimensional computed tomography models were created and exported into point-cloud models. A local coordinate map of the distal humerus and distal femoral articular surfaces was created. The capitellum was compared with the medial and lateral distal femoral condyles, with 2 donor zones in each condyle (medial trochlea and medial intercondylar notch or lateral trochlea and lateral intercondylar notch). In each capitellum 4 combinations of 10-mm defects were simulated (central and lateral, 30° and 45° anterior to shaft of humerus), resulting in 480 capitellum-femur comparative combinations being tested. The capitellum surfaces were virtually placed on a point on the femoral articular surface in 3-dimensional space. The least distances (i.e., the shortest distance from the point in question to the corresponding point in space) between the point clouds on the distal humerus and distal femoral articular surfaces were calculated. There was a less than 0.1-mm difference in the topographic articular surface match among the 4 commonly used donor sites of the distal femur and 4 recipient sites of the capitellum. However, the best match for any given 10-mm capitellar defect (central 30°, central 45°, lateral 30°, and lateral 45°) was the same such that the lateral trochlea on the femur always yielded the best fit compared with the 3 other graft locations (P < .005). Our results indicate that there is a less than 0.1-mm difference in the topographic articular surface match among the 4 commonly used donor sites of the distal femur and the capitellum. The findings suggest that all 4 donor sites provide close articular matching for the capitellum articular surface, with the lateral trochlea articular surface providing the best match. These data suggest that a single donor plug may be obtained from multiple sites in the knee and placed into capitellar lesions with an excellent topographic articular surface match. The findings of our study will be useful to surgeons when managing capitellar osteochondritis dissecans lesions.

The effect of equine-derived bone protein extract (Colloss-E) in the treatment of cavitary bone defects: an experimental study.

Bone protein extract (BPE) usually requires a carrier or a scaffold for implantation. We aimed to compare the effect of equine-derived BPE, an osteoinductive agent composed of a high amount of type-I collagen and other bone proteins (Colloss-E), with that of human demineralized bone matrix (DBM) for treating cavitary bone defects not requiring scaffold use. Rabbit distal femoral condyle was used as a stable cavitary bone defect model. Bone defects of 6-mm diameter and 10-12-mm depth were created in the femoral condyles. Rabbits were assigned into the equine-derived BPE (BPE), human-derived DBM (DBM), and control (C) groups. Approximately 20 mg of BPE was implanted into the defect in the equine-derived BPE group (n=6), whereas 0.3 cc of DBM was implanted in the DBM group (n=6). Defects were left empty in the C group (n=6). The defect area was histologically examined after 6 weeks. There were no instances of macroscopic defect collapse or failure. Histopathological examination revealed that the BPE group had better scores (statistically significant) than both the other groups in terms of quality of union. The BPE group also had higher scores than the DBM group in terms of graft incorporation and new-bone formation. The current study revealed results consistent with those of the previous studies concerning BPEs. Equine-derived BPE was found to be successful for treating cavitary bone defects not requiring scaffold use.

Comparison Between Standard and Gender-Specific Knee Designs in Total Knee Arthroplasty in Female Patients

Objectives: Current study is a comparative, prospective, randomized, short-term outcome study to compare the early results of Total Knee Arthroplasty in female patients using either standard or gender-specific knee prosthesis for treatment of advanced osteoarthritis of the knee joint. Background: Gender-specific knee athroplasty prosthesis is designed to better accommodate the differences noted in distal femoral anatomy in female patients compared to males. Several studies have reported differences in knee morphometry between genders such as the height/width ratio of the distal femoral condyle, the quadriceps angle and the shape of the distal femur. The need for Gender-specific (GS) femoral prostheses is still debated and has led us to compare short-term outcomes of TKA using standard (STD) or GS femoral components. Methods: In the period between February 2012 and February 2013, a comparative prospective randomized study was conducted involving 34 female patients with 40 knees who underwent primary total knee arthroplasty for knee joint advanced osteoarthritis and divided into two groups , The first group included 20 knees underwent total knee arthroplasty using Gender-Specific Knee Design with Gender-Specific femoral component (Zimmer Gender Solutions NexGen High-Flex ( NexGen LPS-Flex ) Implant , The second group included 20 knees underwent total knee arthroplasty using standard Knee Design with Standard femoral component (Zimmer NexGen LPS Implant). Results: No statistically significant differences were observed between the two groups regarding pain improvement, range of motion improvement, pre and post operative OXFORD scores, Knee Society Scores, WOMAC scores, satisfaction, preference, complications, and radiographic results. Conclusion: Early clinical outcomes for the knees with a gender-specific NexGen LPS-Flex prosthesis were similar to those for the knees with a standard NexGen LPS prosthesis in female patients. gender-specific knee prosthesis showed no advantages over standard unisex knee prosthesis in terms of early clinical outcomes.

In vivo performance of novel soybean/gelatin-based bioactive and injectable hydroxyapatite foams

Major limitations of calcium phosphate cements (CPCs) are their relatively slow degradation rate and the lack of macropores allowing the ingrowth of bone tissue. The development of self-setting cement foams has been proposed as a suitable strategy to overcome these limitations. In previous work we developed a gelatine-based hydroxyapatite foam (G-foam), which exhibited good injectability and cohesion, interconnected porosity and good biocompatibility in vitro. In the present study we evaluated the in vivo performance of the G-foam. Furthermore, we investigated whether enrichment of the foam with soybean extract (SG-foam) increased its bioactivity. G-foam, SG-foam and non-foamed CPC were implanted in a critical-size bone defect in the distal femoral condyle of New Zealand white rabbits. Bone formation and degradation of the materials were investigated after 4, 12 and 20weeks using histological and biomechanical methods. The foams maintained their macroporosity after injection and setting in vivo. Compared to non-foamed CPC, cellular degradation of the foams was considerably increased and accompanied by new bone formation. The additional functionalization with soybean extract in the SG-foam slightly reduced the degradation rate and positively influenced bone formation in the defect. Furthermore, both foams exhibited excellent biocompatibility, implying that these novel materials may be promising for clinical application in non-loaded bone defects.

Can femoral rotation be localized and quantified using standard CT measures?

The terms "femoral anteversion" and "femoral torsion" have often been used interchangeably in the orthopaedic literature, yet they represent distinct anatomical entities. Anteversion refers to anterior tilt of the femoral neck, whereas torsion describes rotation of the femoral shaft. Together, these and other transverse plane differences describe what may be considered rotational deformities of the femur. Assessment of femoral rotation is now routinely measured by multiple axial CT methods. The most widely used radiographic technique (in which only two CT-derived axes are made, one through the femoral neck and one at the distal femoral condyles) may not accurately quantify proximal femoral anatomy nor allow identification of the anatomic locus of rotation. (1) What CT methodology (a two-axis CT-derived technique, a three-axis technique adding an intertrochanteric axis--the "Kim method," or a volumetric three-dimensional reconstruction of the proximal femur) most accurately quantifies transverse plane femoral morphology; (2) localizes those deformities; and (3) is most reproducible across different observers? We constructed a high-definition femoral sawbones model in which osteotomies were performed at either the intertrochanteric region or femoral shaft. Transverse plane deformity was randomly introduced and CT-derived rotational profiles were constructed using three different CT methods. Accuracy and consistency of measurements of femoral rotation were calculated using p values and Fisher's exact test and intraclass correlation coefficients (ICCs). All three CT methodologies accurately quantified overall transverse plane rotation (mean differences 0.69° ± 3.88°, 0.69° ± 3.88°, and -1.09° ± 4.44° for the two-plane, Kim, and volumetric methods, respectively). However, use of a single neck and single distal femoral axis does not reliably identify the anatomic locus of rotation, whereas the Kim and volumetric methods do (p < 0.0001). All three methods were highly reproducible between observers (ICCs of 0.9569, 0.9569, and 0.9359 for the traditional two-plane, Kim, and volumetric methods, respectively). Only the Kim and volumetric methods can identify the anatomic location of transverse plane rotation and we recommend using one of the two techniques. Accurate anatomic localization of transverse plane rotation enables using precise anatomic terminology ("femoral torsion" versus "femoral [ante]version"). Current descriptions and treatment of femoral rotational deformities do not discriminate the location of rotation. The transverse plane femoral rotation requires a precise definition based on its anatomic location to maintain consistent communication between clinicians, because version of the neck and torsion of the shaft may have different treatment.

Efficacy of a small cell-binding peptide coated hydroxyapatite substitute on bone formation and implant fixation in sheep.

Cylindrical critical size defects were created at the distal femoral condyles bilaterally of eight female adult sheep. Titanium implants with 2-mm concentric gaps were inserted and the gaps were filled with one of the four materials: allograft; a synthetic 15-amino acid cell-binding peptide coated hydroxyapatite (ABM/P-15); hydroxyapatite + βtricalciumphosphate+ Poly-Lactic-Acid (HA/βTCP-PDLLA); or ABM/P-15+HA/βTCP-PDLLA. After nine weeks, bone-implant blocks were harvested and sectioned for micro-CT scanning, push-out test, and histomorphometry. Significant bone formation and implant fixation could be observed in all four groups. Interestingly, the microarchitecture of the ABM/P-15 group was significantly different from the control group. Tissue volume fraction and thickness were significantly greater in the ABM/P-15 group than in the allograft group. Bone formation and bone ingrowth to porous titanium implant were not significantly different among the four groups. The ABM/P-15 group had similar shear mechanical properties on implant fixation as the allograft group. Adding HA/βTCP-PDLLA to ABM/P-15 did not significantly change these parameters. This study revealed that ABM/P-15 had significantly bone formation in concentric gap, and its enhancements on bone formation and implant fixation were at least as good as allograft. It is suggested that ABM/P-15 might be a good alternative biomaterial for bone implant fixation in this well-validated critical-size defect gap model in sheep. Nevertheless, future clinical researches should focus on prospective, randomized, controlled trials in order to fully elucidate whether ABM/P-15 could be a feasible candidate for bone substitute material in orthopedic practices.

How precise is computer-navigated gap assessment in TKA?

Methods to improve gap balancing in total knee arthroplasty (TKA) include the development of calibrated distractors and various devices to determine the distances of the gaps. However, few studies have validated the accuracy or precision of computer navigation to determine these measurements, especially gaps created after bone cuts have been made; doing so would be important, because optimal surgical technique relies on appropriate gap spacing. We investigated the ability of a new image-free computer navigation surface registration protocol to measure gap distances in TKA. Eight embalmed cadaveric specimens of the lower extremity were used. A surface registration software protocol defined the most distal and posterior surface points of the femoral condyles and the navigation system measured the distance of the most distal femoral condyle point to the surface of the tibia after tibial resection. The tibial resection was perpendicular to the mechanical axis and was cut with a 7° posterior slope. The navigation system measured gaps spaced by modular spacing blocks at 5° intervals from full extension to 120° of flexion. Repeatability assessed repeated measures by one surgeon. Reproducibility was assessed by performing the same measurements after complete reregistration of the computer protocol to the cadaver bones. The gaps measured by the computer were statistically the same as those assessed with the use of blocks with a maximum measurement error of 1mm. Reregistration did introduce error into the measurement. The gaps changed with position of knee flexion, and there was gradual and significant stretching of the gaps with repeated measurements. Preliminary testing shows that computer navigation can reproduce static measurements reliably and with equal accuracy as spacer blocks. We have not demonstrated that this could be applied in a dynamic setting. This computer navigation system has sufficient precision to warrant investigation in the clinical setting for measuring gaps created during the surgical procedure.

Tumor-Induced Osteomalacia Secondary to a Fibroblast Growth Factor 23-Secreting Phosphaturic Mesenchymal Tumor in the Foot.

Tumor-induced osteomalacia (TIO) is usually caused by humoral factors that are secreted by a phosphaturic mesenchymal tumor. Fibroblast growth factor 23 (FGF-23) is predominantly produced by osteocytes in a normal physiologic state, but is elevated in many cases of TIO. FGF-23 inhibits phosphate reabsorption in the proximal renal tubule and also inhibits 1α-hydroxylase, resulting in decreased 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) levels. We describe a patient who presented with symptoms of osteomalacia and was found to have a phosphaturic mesenchymal tumor in the soft tissue of the foot. The patient was informed that data concerning the case would be submitted for publication, and he provided consent. A fifty-eight-year-old man presented with multiple episodes of insufficiency fractures and diffuse pain involving the knees, hips, and feet. The patient was well and physically active until two and one-half years prior, when he experienced severe pain in the left knee and leg after playing soccer. Despite physical therapy and corticosteroid injections, the patient continued to have severe pain that gradually limited weight-bearing and walking. Laboratory tests revealed low phosphorus (1.3 mg/dL; reference range, 2.5-4.5 mg/dL), low 1,25(OH)2D3 (12 pg/mL; reference range, 18-72 pg/mL), and elevated alkaline phosphatase (260 U/L; reference range, 38-126 U/L). Rheumatologic workup, including erythrocyte sedimentation rate, antinuclear antibody, and rheumatoid factor, was negative. Radiographs did not reveal obvious fractures, but magnetic resonance imaging (MRI) and whole body technetium-99m bone scintigraphy revealed findings consistent with multiple stress and insufficiency fractures involving the sixth and eleventh ribs, the right tibial plateau, the left calcaneus, the distal part of the tibia, the distal femoral condyles, the fibular head, and the lateral tibial condyle. Bone densitometry revealed a T score of –2.6 in the femoral neck region, consistent with osteoporosis. Prior to presentation to our office, the patient continued …

Does Low-intensity pulsed ultrasound treatment repair articular cartilage injury? A rabbit model study

BackgroundLow-intensity pulsed ultrasound (LIPUS) regiment has been used to treat fractures with non-union and to promote bone union in general. The effect of LIPUS on articular cartilage metabolism has been characterized. Yet, the effect of LIPUS to repair articular cartilage injury remains unclear in vivo.MethodsWe designed a study to investigate the effect of LIPUS on articular cartilage repairing in a rabbit severe cartilage injury model. Eighteen rabbits were divided into three groups: Sham-operated group, operated group without-LIPUS-treatment, operated group with-LIPUS-treatment (a daily 20-minute treatment for 3 months). Full-thickness cartilage defects were surgically created on the right side distal femoral condyle without intending to penetrate into the subchondral bone, which mimicked severe chondral injury. MR images for experimental joints, morphology grading scale, and histopathological Mankin score were evaluated.ResultsThe preliminary results showed that the operated groups with-LIPUS-treatment and without-LIPUS-treatment had significantly higher Mankin score and morphological grading scale compared with the sham-operated group. However, there was no significant difference between the with-LIPUS-treatment and without-LIPUS-treatment groups. Cartilage defects filled with proliferative tissue were observed in the with-LIPUS-treatment group grossly and under MR images, however which presented less up-take under Alcian blue stain. Furthermore, no new deposition of type II collagen or proliferation of chondrocyte was observed over the cartilage defect after LIPUS treatment.ConclusionLIPUS has no significant therapeutic potential in treating severe articular cartilage injury in our animal study.