Automatic software-based 3D-angular measurement for weight-bearing CT (WBCT) is valid.

BACKGROUND: The purpose of this study was to compare automatic software-based angular measurement (AM) with validated measurement by hand (MBH) regarding angle values and time spent for Weight-Bearing CT (WBCT) generated datasets. METHODS: Five-hundred WBCT scans from different pathologies were included in the study. 1st - 2nd intermetatarsal angle, talo-1st metatarsal angle dorsoplantar and lateral, hindfoot angle, calcaneal pitch angle were measured and compared between MBH and AM. RESULTS: The pathologies were ankle osteoarthritis/instability, n = 147 (29%); Haglund deformity/Achillodynia, n = 41 (8%); forefoot deformity, n = 108 (22%); Hallux rigidus, n = 37 (7%); flatfoot, n = 35 (7%); cavus foot, n = 10 (2%); osteoarthritis except ankle, n = 82 (16%). The angles did not differ between MBH and AM (each p > 0.36). The time spent for MBH / AM was 44.5 / 1 s on average per angle (p < .001). CONCLUSIONS: AM provided angles which were not different from validated MBH and can be considered as a validated angle measurement method. The time spent was 97% lower for AM than for MBH. LEVELS OF EVIDENCE: Level III.

Comparison of Total Joint Replacement With Arthrodesis of the First Metatarsophalangeal Joint.

BACKGROUND: The aim of this study was to compare outcome (clinical, patient-reported outcome measures, radiologic, joint motion and pedographic) of total joint replacement with Roto-Glide (RG) and arthrodesis (A) for severe osteoarthritis of the first metatarsophalangeal joint (MTP1). METHODS: All consecutive patients with arthrodesis and RG from January 23, 2011, until September 18, 2019, at the authors' institution were considered for inclusion in the study. Preoperatively and at follow-up (FU), radiographs, and/or weightbearing computed tomographic imaging were obtained. Standard dynamic pedography was performed. Visual analog scale foot and ankle (VASFA), European Foot and Ankle Society (EFAS) score, MTP1 range of motion for dorsiflexion/plantarflexion (DF/PF) were registered and compared preoperatively and at FU. RESULTS: Seventy RG and 72 arthrodesis patients were included. Preoperative VASFA and EFAS scores did not differ between the RG and arthrodesis groups (average scores: VASFA, 50.6 and 45.6; EFAS score, 10.7 and 10.6, respectively; each P > .05). Wound healing delays without further operative measures were registered in 4 patients (6%) for RG and 5 (7%) for arthrodesis (P = .67), and 5 revisions in 5 patients (7%) for RG and 12 in 8 (11%) for arthrodesis (P = .05). The longest available FU was higher in RG than in arthrodesis (47 vs 37 months on average, P < .001). Pedography showed higher first metatarsal head or sesamoids and lower great toe force percentage from force of entire foot in RG than in arthrodesis (P = .05) resulting in physiological pattern in RG only. VASFA and EFAS scores at FU was higher in RG than in arthrodesis (average scores: VASFA, 72.6 and 63.6; EFAS score, 16.1 and 14.1, respectively; each P < .05). DF/PF measurement was only possible in RG (average value: DF/PF, 36.1/14.0). CONCLUSION: We found marginally lower revision rates and higher patient-reported outcome measures, joint motion (DF/PF), and more physiologic force distribution at slightly longer FU for the RG group than the arthrodesis group. Longer follow-up and broader clinical reporting are needed to identify the potential deficits of RG. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Autologous matrix induced chondrogenesis plus peripheral blood concentrate (AMIC+PBC) in chondral lesions at the ankle as part of a complex surgical approach - 5-year follow-up.

BACKGROUND: The aim of the study was to assess 5-year-follow-up (5FU) after Autologous Matrix Induced Chondrogenesis plus Peripheral Blood Concentrate (AMIC+PBC) in chondral lesions at the ankle as part of a complex surgical approach. METHODS: In a prospective consecutive non-controlled clinical follow-up study, all patients with chondral lesion at the ankle treated with AMIC+PBC from July 17, 2016 to May 31, 2017 were included. Size and location of the chondral lesions, the Visual-Analogue-Scale Foot and Ankle (VAS FA) and the EFAS Score before treatment and at 5FU were analysed and compared with previous 2-year-follow-up (2FU). Peripheral Blood Concentrate (PBC) was used to impregnate a collagen I/III matrix (Chondro-Gide, Wolhusen, Switzerland) that was fixed into the chondral lesion with fibrin glue. RESULTS: One hundred and twenty-nine patients with 136 chondral lesions were included in the study. The chondral lesions were located as follows (n (%)), medial talar shoulder only, 62 (46); lateral talar shoulder only, 42 (31); medial and lateral talar shoulder, 7 (10); tibia, 18 (13). The average for lesion size was 1.8 cm2, for VAS FA 45.7 and for EFAS Score 9.8. 2FU/5FU was completed in 105 (81 %)/104(81 %) patients with 112/111 previous chondral lesions. VAS FA improved to 79.8/84.2 and EFAS Score to 20.3/21.5 (2FU/5FU). No parameter significantly differed 2FU and 5FU. CONCLUSIONS: AMIC+PBC as part of a complex surgical approach led to improved and high validated outcome scores at 2FU/5FU. 2FU and 5FU did not differ.

Autologous matrix induced chondrogenesis plus peripheral blood concentrate (AMIC+PBC) in chondral defects of the first metatarsophalangeal joint - 5-year follow-up.

BACKGROUND: The aim of the study was to assess the 5-year-follow-up (5FU) after Autologous Matrix Induced Chondrogenesis plus Peripheral Blood Concentrate (AMIC+PBC) in chondral defects at the first metatarsophalangeal joint (MTP1). MATERIAL AND METHODS: In a prospective consecutive non-controlled clinical follow-up study, all patients with chondral lesion at MTP1 that were treated with AMIC+PBC from July 17, 2016 to May 31, 2017 were included. Size and location of the chondral lesions, the Visual-Analogue-Scale Foot and Ankle (VAS FA) and the EFAS Score before treatment and at 5FU were analysed and compared with previous 2-year-follow-up (2FU). Peripheral Blood Concentrate (PBC) was used to impregnate a collagen I/III matrix (Chondro-Gide, Wolhusen, Switzerland) that was fixed into the chondral lesion with fibrin glue. RESULTS: One hundred and ninety-eight patients with 238 chondral defects were included. In 21 % of patients no deformities in the forefoot were registered. The average degree of osteoarthritis was 2.2. The chondral defect size was 1.0 cm2 on average. The most common location was metatarsal dorsal (33 %), and in most patients one defect was registered (74 %). Corrective osteotomy of the first metatarsal was performed in 79 %. 176 (89 %)/164 (83 %) patients completed 2FU/5FU. VAS FA/EFAS Score were preoperatively 46.8/11.9 and improved to 74.1/17.1 at 2FU and 75.0/17.3 at 5FU on average. No parameter significantly differed between 2FU and 5FU. CONCLUSIONS: AMIC+PBC as treatment for chondral defects at MTP1 as part of joint preserving surgery led to improved and high validated outcome scores at 2FU and 5FU. The results between 2FU and 5FU did not differ.

Semi-automatic software-based 3D-angular measurement for Weight-Bearing CT (WBCT) in the foot provides different angles than measurement by hand.

BACKGROUND: The purpose of this study was to compare semi-automatic software-based angular measurement (SAM) with previously validated measurement by hand (MBH) regarding angle values and time spent for the investigator for Weight-Bearing CT (WBCT). METHODS: In this retrospective comparative study, five-hundred bilateral WBCT scans (PedCAT, Curvebeam, Warrington, PA, USA) were included in the study. Five angles (1st - 2nd intermetatarsal angle (IM), talo-metatarsal 1-angle (TMT) dorsoplantar and lateral projection, hindfoot angle, calcaneal pitch angle) were measured with MBH and SAM (Bonelogic Ortho Foot and Ankle, Version 1.0.0-R, Disior Ltd, Helsinki, Finland) on the right/left foot/ankle. The angles and time spent of MBH and SAM were compared (t-test, homoscesdatic). RESULTS: The angles differed between MBH and SAM (mean values MBH/SAM; IM, 9.1/13.0; TMT dorsoplantar, -3.4/8.2; TMT lateral. -6.4/-1.1; hindfoot angle, 4.6/21.6; calcaneal pitch angle, 20.5/20.1; each p < 0.001 except the calcaneal pitch angle, p = 0.35). The time spent for MBH / SAM was 44.5 ± 12 s / 12 ± 0 s on average per angle (p < 0.001). CONCLUSIONS: SAM provided different angles as MBH (except calcaneal pitch angle) and can currently not be considered as validated angle measurement method (except calcaneal pitch angle). The investigator time spent is 73% lower for SAM (12 s per angle) than for MBH (44.5 s per angle). SAM might be an important step forward for 3D-angle measurement of WBCT when valid angles are provided.

Automatic software-based 3D-angular measurement for Weight-Bearing CT (WBCT) provides different angles than measurement by hand.

BACKGROUND: Purpose of this study was to compare automatic software-based angular measurement (AM, Autometrics, Curvebeam, Warrington, PA, USA) with previously validated measurement by hand (MBH) regarding angle values and time spent for the investigator for Weight-Bearing CT (WBCT). METHODS: Five-hundred bilateral WBCT scans (PedCAT, Curvebeam, Warrington, PA, USA) were included in the study. Five angles (1st - 2nd intermetatarsal angle, talo-metatarsal 1-angle (TMT) dorsoplantar and lateral projection, hindfoot angle, calcaneal pitch angle) were measured with MBH and AM on the foot/ankle (side with pathology). Angles and time spent of MBH and AM were compared (t-test, homoscedatic). RESULTS: The specific pathologies were ankle osteoarthritis/instability, n = 147 (29%); Haglund deformity/Achillodynia, n = 41 (8%); forefoot deformity, n = 108 (22%); Hallux rigidus, n = 37 (7%); flatfoot, n = 35 (7%); cavus foot, n = 10 (2%); osteoarthritis except ankle, n = 82 (16%). The angles differed between MBH and AM (each p < 0.001) except the calcaneal pitch angle (p = 0.05). The time spent for MBH / AM was 44.5 ± 12 s / 1 ± 0 s on average per angle (p < 0.0011). CONCLUSIONS: AM provided different angles as MBH and can currently not be considered as validated angle measurement method. The investigator time spent is 97% lower for AM (1 s per angle) than for MBH (44.5 s per angle). Cases with correct angles in combination with almost no time spent showed the real potential of AM. The AM system will have to become reliable (especially in diminishing positive and negative angle values as defined) and valid which has to be proven by planned studies in the future. LEVEL OF EVIDENCE: Level III.

Comparison of clinically used bilayer collagen membrane and trilayer collagen prototype fixation stability in chondral defects at the talus - An experimental human specimen study.

BACKGROUND: The purpose of this human specimen experimental study was to compare the fixation stability of clinically used bilayer collagen membrane with fibrin glue with trilayer collagen prototype without fibrin glue in chondral defects at the medial or lateral talar shoulder (both matrices from Geistlich Pharma AG, Wollhusen, Switzerland). METHODS: Eleven human specimens were used. The membranes were implanted in standardized chondral defects at the medial and lateral talar shoulder randomized. All tests were performed in load-control 15 kg. Range of motion ROM of each ankle was examined individually before testing. The average ROM was 10° dorsiflexion range 0°-20° and 30° plantarflexion range 20°-45°. 1,000 testing cycles with the defined ROM were performed. Two independent investigators, blinded to membrane and fixation type, visually assessed the membrane fixation integrity for peripheral detachment, area of defect uncovered, membrane constitution and delamination. RESULTS: The clinically used bilayer collagen membrane plus fibrin glue showed higher fixation stability than the trilayer prototype (all p < 0.05). No significant differences occurred between medial and lateral talar shoulder location (all p > 0.05). CONCLUSIONS: The fixation stability of the trilayer collagen prototype without fibrin glue is lower than of the clinically used bilayer membrane with fibrin glue in chondral defects at the medial and lateral talar shoulder in an experimental human specimen test. Clinical use of trilayer collagen prototype without fibrin glue has to be validated by clinical testing to evaluate if the lower stability of fixation is still sufficient.

Comparison Matrix-Associated Stem Cell Transplantation (MAST) with Autologous Matrix Induced Chondrogenesis plus Peripheral Blood Concentrate (AMIC+PBC) in chondral lesions at the ankle-A clinical matched-patient analysis.

BACKGROUND: The aim of the study was to compare Matrix-Associated Stem Cell Transplantation (MAST) with Autologous Matrix Induced Chondrogenesis plus Peripheral Blood Concentrate (AMIC+PBC) in chondral lesions at the ankle. METHODS: In a matched-patient clinical follow-up study, patients with chondral lesion at the ankle that were treated with MAST from April 1, 2009 to July 15, 2016, and patients that were treated with AMIC+PBC from July 17, 2016 to May 31, 2017 were included and compared. Size and location of the chondral lesions and the Visual-Analogue-Scale Foot and Ankle (VAS FA) before treatment and at follow-up were analysed. Bone Marrow Aspirate Concentrate (BMAC) was used for MAST and Peripheral Blood Concentrate (PBC) for AMIC+PBC to impregnate a collagen I/III matrix (Chondro-Gide, Wollhusen, Switzerland) that was fixed into the chondral lesion with fibrin glue. RESULTS: One hundred and twenty-nine patients with 136 chondral lesions were included in both groups. The chondral lesions were located as follows (MAST/AMIC+PBC, n (%)), medial talar shoulder only, 59 (43)/62 (46); lateral talar shoulder only, 44 (32)/42 (31); medial and lateral talar shoulder, 7 (10)/7 (10); tibia, 19 (14)/18 (13). The lesion size was 1.6/1.8cm2 on average and VAS FA was 46.9/45.7 (MAST/AMIC+PBC). For MAST/AMIC+PBC groups, 107 (83%)/105 (81%) with 112/110 previous chondral lesions completed the defined 2-year-follow-up after 24.4/23.8 months on average. VAS FA improved to 82.3/79.8 (MAST/AMIC+PBC). No parameter significantly differed between MAST and AMIC+PBC groups. CONCLUSIONS: MAST and AMIC+PBC as part of a complex surgical approach led to improved and high validated outcome scores in 2-year-follow-up. MAST and AMIC+PBC showed similar results.

Matrix-associated stem cell transplantation (MAST) in chondral lesions at the ankle as part of a complex surgical approach- 5-year-follow-up in 100 patients.

BACKGROUND: The aim of the study was to assess the 5-year-follow-up after matrix-associated stem cell transplantation (MAST) in chondral lesions at the ankle as part of a complex surgical approach. METHODS: In a prospective consecutive non-controlled clinical follow-up study, all patients with chondral lesion at the ankle that were treated with MAST from April 1, 2009 to May 31, 2012 were included. Size and location of the chondral lesions, method-associated problems and the Visual-Analogue-Scale Foot and Ankle (VAS FA) before treatment and at follow-up were analysed. Stem cell-rich blood was harvested from the ipsilateral pelvic bone marrow and centrifuged (10min, 1500RPM). The supernatant was used to impregnate a collagen I/III matrix (Chondro-Gide) that was fixed into the chondral lesion with fibrin glue. RESULTS: One hundred and twenty patients with 124 chondral lesions were included in the study. Age at the time of surgery was 35 years on average (range, 12-65 years), 74 (62%) were male. VAS FA before surgery was 45.2 on average (range, 16.4-73.5). Lesions were located at medial talar shoulder, n=55; lateral talar shoulder, n=58 (medial and lateral, n=4); tibia, n=11. Lesion size was 1.7cm2 on average (range, .8-6cm2). One hundred patients (83%) completed 5-year-follow-up after. VAS FA improved to 84.4 (range, 54.1-100; t-test, p<0.01). CONCLUSIONS: MAST as part of a complex surgical approach led to improved and high validated outcome scores in the mid-term-follow-up. No method related complications were registered. Even though a control group is missing, we conclude that MAST as part of a complex surgical approach is an effective method for the treatment of chondral lesions of the ankle for at least five years.

Combination of PedCAT Weightbearing CT With Pedography Assessment of the Relationship Between Anatomy-Based Foot Center and Force/Pressure-Based Center of Gravity.

BACKGROUND: A customized pedography sensor (Pliance; Novel, Munich, Germany) was inserted into a pedCAT (Curvebeam, Warrington, PA). The aim of this study was to analyze the relative position of the anatomical foot center (FC) and the pedographic center of gravity (COG). The hypothesis was that FC should be a good predictor of mediolateral position of COG but not longitudinal since hindfoot anatomy allows free anteroposterior movement but limited mediolateral movement. METHODS: In 90 patients (180 feet), a pedCAT scan with simultaneous pedography with full weightbearing in a standing position was performed. The morphology-based definition of the FC was performed with the pedCAT data following the Torque Ankle Lever Arm System (TALAS) algorithm. The force/pressure-based COG was defined with the pedography data using a software-based algorithm. The distance between FC and COG and the direction of a potential shift (distal-proximal, mediolateral) was measured and analyzed. COG motion during data acquisition was recorded and analyzed. Mean age of patients was 53.8 (range, 17-84) years, and 57 (63%) were female. RESULTS: The distance between FC and COG was 28.7 mm on average (range, 0-60). FC was distal to COG in 175 feet (97%; mean, 27.5 mm; range, -15 to 60) and lateral in 112 feet (62%; mean, 2.0 mm; range, -18 to 20). CONCLUSIONS: There was a constant and major distal longitudinal shift of COG relative to FC and an inconstant minor mediolateral shift. CLINICAL RELEVANCE: The data might be taken into consideration for planning and follow-up in foot and ankle surgery.

Matrix-associated stem cell transplantation (MAST) in chondral defects of the ankle is safe and effective - 2-year-followup in 130 patients.

BACKGROUND: The aim of the study was to assess the 2-year-follow-up of matrix-associated stem cell transplantation (MAST) in chondral defects of the ankle. METHODS: In a prospective consecutive non-controlled clinical follow-up study, all patients with chondral defect that were treated with MAST from October 1, 2011 to July 31, 2013 were analyzed. Size and location of the chondral defects, method-associated problems and the Visual Analogue Scale Foot and Ankle (VAS FA) before treatment and at follow-up were analyzed. Stem cell-rich blood was harvested from the ipsilateral pelvic bone marrow and centrifuged (10min, 1500rpm). The supernatant was used to impregnate a collagen I/III matrix (Chondro-Gide). The matrix was fixed into the chondral defect with fibrin glue. RESULTS: One hundred and forty-four patients with 150 chondral defects were included in the study. The age of the patients was 35 years on average (range, 12-68 years), 85 (59%) were male. The VAS FA before surgery was 48.5 on average (range, 16.5-78.8). The defects were located as follows, medial talar shoulder, n=62; lateral talar shoulder, n=66 (medial and lateral talar shoulder, n=6), tibia, n=22. The defect size was 1.6cm2 on average (range, .6-6cm2). 130 patients (90%) completed 2-year-follow-up. The VAS FA improved to an average of 87.5 (range, 62.1-100; t-test (comparison with preoperative scores), p=.01). CONCLUSIONS: MAST led to improved and high validated outcome scores. No method related complications were registered. Even though a control group is missing, we conclude that MAST is a safe and effective method for the treatment of chondral defects of the ankle.

Matrix-associated stem cell transplantation (MAST) in chondral defects of the 1st metatarsophalangeal joint is safe and effective-2-year-follow-up in 20 patients.

The aim of the study was to assess the 2-year-follow-up of matrix-associated stem cell transplantation (MAST) in chondral defects of the 1st metatarsophalangeal joint (MTPJ). In a prospective consecutive non-controlled clinical follow-up study, 20 patients with 25 chondral defect at the 1st MTPJ that were treated with MAST from October 1st, 2011 to March, 30th, 2013 were analysed. The size and location of the chondral defects range of motion (ROM), and the Visual-Analogue-Scale Foot and Ankle (VAS FA) before treatment and at follow-up were registered. Stem cell-rich blood was harvested from the ipsilateral pelvic bone marrow and centrifuged (10min, 1500 RPM). The supernatant was used to impregnate a collagen I/III matrix (Chondro-Guide). The matrix was fixed into the chondral defect with fibrin glue. The age of the patients was 42 years on average (range, 35-62 years). The VAS FA before surgery was 50.5 (range, 18.3-78.4). The defects were located as follows, dorsal metatarsal head, n=12, plantar metatarsal head, n=5, dorsal & plantar, n=8 (two defects, n=5). The defect size was 0.7cm2 (range, .5-2.5cm2). ROM was 10.3/0/18.8° (dorsal extension/plantar flexion). All patients completed 2-year-follow-up. VAS FA improved to 91.5 (range, 74.2-100; t-test, p<.01). ROM improved to 34.5/0/25.5 (p=.05). The surgical treatment including MAST led to improved clinical scores and ROM. Even though a control group is missing, we conclude that MAST is a safe and effective method for the treatment of chondral defects of the 1st MTPJ.

Tibiotalocalcaneal arthrodesis with a triple-bend intramedullary nail (A3)-2-year follow-up in 60 patients.

BACKGROUND: The aim of the study was to analyze the clinical aspects including 2-year follow-up of tibiotalocalcaneal arthrodesis (TTCA) with a triple-bend retrograde intramedullary nail (A3, Stryker, Airview Boulevard, MN, USA). METHODS: All patients with TTCA with A3 between October 18, 2011 and April 29, 2013 were included. Visual Analogue Scale Foot and Anklenkle (VAS FA), indications for surgery, details of surgery, radiographic measurements, and complications were analyzed. RESULTS: A total of 66 patients were included. The mean VAS FA was 29.6. Most common indications were arthrosis (n=43; 65%) and deformity (n=36; 55%). The accuracy of correction and implant position was 9.4 (maximum 10) on average. Infection rate was 3% (n=2). Sixty (91%) patients completed follow-up: VAS FA 59.9, fusion rate 100%, high accuracy of correction and implant position. CONCLUSIONS: TTCA with the A3 implant system showed accurate correction and implant position. Two-year follow-up in 60 patients (91%) showed good clinical outcome scores and 100% fusion rate.

Combination of pedCAT® for 3D Imaging in Standing Position With Pedography Shows No Statistical Correlation of Bone Position With Force/Pressure Distribution.

pedCAT(®) (CurveBeam, Warrington, PA) is a technology for 3-dimensional (3D) imaging with full weightbearing that has been proved to exactly visualize the 3D bone position. For the present study, a customized pedography sensor (Pliance; Novel, Munich, Germany) was inserted into the pedCAT(®). The aim of our study was to analyze the correlation of the bone position and force/pressure distribution. A prospective consecutive study of 50 patients was performed, starting July 28, 2014. All patients underwent a pedCAT(®) scan and simultaneous pedography with full weightbearing in the standing position. The following parameters were measured on the pedCAT(®) image for the right foot by 3 different investigators 3 times: lateral talo-first metatarsal angle, calcaneal pitch angle, and minimum height of the fifth metatarsal base, second to fifth metatarsal heads, and medial sesamoid. From the pedography data, the following parameters were defined using the standardized software algorithm: midfoot contact area, maximum force of midfoot, maximum force of midfoot lateral, maximum force of entire foot, and maximum pressure of first to fifth metatarsal. The values of the corresponding pedCAT(®) and pedographic parameters were correlated (Pearson). The intra- and interobserver reliability of the pedCAT(®) measurements were sufficient (analysis of variance, p > .8 for each, power >0.8). No sufficient correlation was found between the pedCAT(®) and pedographic parameters (r < 0.05 or r > -0.38).3D bone position did not correlate with the force and pressure distribution under the foot sole during simultaneous pedCAT(®) scanning and pedography. Thus, the bone positions measured with pedCAT(®) do not allow conclusions about the force and pressure distribution. However, the static pedographic parameters also do not allow conclusions about the 3D bone position.one position and force/pressure distribution are important parameters for diagnostics, planning, and follow-up examinations in foot and ankle surgery.

PedCAT for 3D-imaging in standing position allows for more accurate bone position (angle) measurement than radiographs or CT.

BACKGROUND: PedCAT (Curvebeam, Warrington, USA) is a new technology that allows 3D-imaging with full weight bearing which is not influenced by projection and/or foot orientation (as radiographs). The aim of this study was to compare time spent of the image acquisition, and comparison of specific bone position (angle) measurements between three imaging methods (radiographs, CT, pedCAT), and to analyze and compare measurement differences and inter- and intraobserver reliability. METHODS: In a prospective consecutive controlled study, 30 patients in which standard digital radiographs with full weight bearing in standing position (feet bilateral dorsoplantar and lateral views and Saltzman hindfoot view), CT without weight bearing, and pedCAT scan with full weight bearing in standing position were included, starting July 1, 2013. The following angles were measured for the right foot by three different investigators three times: 1st - 2nd intermetatarsal angle, talo-metatarsal 1-angle (TMT) both dorsoplantar and lateral projection, hindfoot angle, calcaneal pitch. The angles were digitally measured and compared (ANOVA with Post Hoc Scheffe test). RESULTS: The angles differed between radiographs, CT and pedCAT (ANOVA, all p≤.01). The angles differed between pedCAT and both radiographs and CT (Post Hoc Scheffe test, each p≤.05 except for TMT dorsoplantar and calcaneal pitch angels versus radiographs). CONCLUSIONS: The angles differed between radiographs, CT and pedCAT, indicating that only pedCAT is able to detect the correct angles. PedCAT includes weight bearing in contrast to CT. PedCAT prevents inaccuracies of projection and foot orientation in contrast to radiographs due to the 3D dataset which is principally independent from projection and foot orientation.

Biomechanical comparison of stability of tibiotalocalcaneal arthrodesis with two different intramedullary retrograde nails.

BACKGROUND: The aim of the study was to compare the initial construct stability of two retrograde intramedullary nail systems for tibiotalocalcaneal arthrodesis (TTCF) (A3, Small Bone Innovations; HAN, Synthes) in a biomechanical cadaver study. METHODS: Nine pairs of human cadaver bones were instrumented with two different retrograde nail systems. One tibia from each pair was randomized to either rod. The bone mineral density was determined via tomography to ensure the characteristics in each pair of tibiae were similar. All tests were performed in load-control. Displacements and forces were acquired by the sensors of the machine at a rate of 64Hz. Specimens were tested in a stepwise progression starting with six times ±125N with a frequency of 1Hz for 250cycles each step was performed (1500cycles). The maximum load was then increased to ±250N for another 14 steps or until specimen failure occurred (up to 3500cycles). RESULTS: Average bone mineral density was 67.4mgHA/ccm and did not differ significantly between groups (t-test, p=.28). Under cyclic loading, the range of motion (dorsiflexion/plantarflexion) at 250N was significantly lower for the HAN-group with 7.2±2.3mm compared to the A3-group with 11.8±2.9mm (t-test, p<0.01). Failure was registered for the HAN after 4571±1134cycles and after 2344±1195cycles for the A3 (t-test, p=.031). Bone mineral density significantly correlated with the number of cycles to failure in both groups (Spearman-Rho, r>.69, p<0.01). CONCLUSIONS: The high specimen age and low bone density simulates an osteoporotic bone situation. The HAN with only lateral distal bend but two calcaneal locking screws showed higher stability (higher number of cycles to failure and lower motion such as dorsiflexion/plantarflexion during cyclic loading) than the A3 with additional distal dorsal bend but only one calcaneal locking screw. Both constructs showed sufficient stability compared with earlier data from a similar test model. CLINICAL RELEVANCE: The data suggest that both implants allow for sufficient primary stability for TTCF in osteoporotic and consequently also in non-osteoporotic bone. LEVEL OF EVIDENCE: Not applicable, experimental basic science study.

Arthrorisis with calcaneostop screw in children corrects Talo-1st Metatarsal-Index (TMT-Index).

BACKGROUND: Arthrorisis (other terms: Arthrorhisis or Arthroreisis) with calcaneostop screw is one option for the treatment of flatfoot (Pes abductoplanovalgus) in children. The aim of the study was to analyze the amount of correction (for example Talo-1st Metatarsal-Index (TMT-Index)) and clinical outcome including pedographic assessment. METHODS: In a prospective consecutive non-controlled clinical follow-up study, all patients that were treated with arthrorisis with calcaneostop screw from September 1st 2006 to August 31st, 2009 were included. One foot was operated at a time, and the contralateral foot was operated 3 months later if indicated. Postoperatively, 15 kg partial weight-bearing was performed for 6 weeks. The screws were removed after 2-year-followup. Assessment was performed before surgery, at two-year-followup, and at 2.5-year-followup. The assessment staging of posterior tibialis insufficiency, radiographs with full weight bearing (TMT-Index), pedography, and Visual-Analogue-Scale Foot and Ankle (VAS FA). RESULTS: 18 patients/31 feet were included in the study (age, 10.6 [8-12], 45% male). No complications were observed. In comparison with the preoperative parameters, the parameters posterior tibialis insufficiency stage, percentage of increased pedographic midfoot contact area and force were decreased, and TMT dorsoplantar/lateral/Index and VAS FA scores were increased at both followups (each p<.05). The parameters did not differ between followups (each p ≥.4). CONCLUSIONS: All relevant parameters (stage of posterior tibialis insufficiency, TMT dorsoplantar/lateral/Index, pedographic midfoot contact area and force, VAS FA) improved after arthrorisis with calcaneostop screw (before and after screw removal) in pes abductoplanovalgus in children. Since the complication rate is very low, this method allows safe and predictable correction.

Matrix-associated stem cell transplantation (MAST) in chondral defects of foot and ankle is effective.

BACKGROUND: The aim of the study was to assess the feasibility and clinical results of matrix-associated stem cell transplantation (MAST) and 2-year-follow-up in chondral defects of foot and ankle. METHODS: In a prospective, consecutive, non-controlled clinical follow-up study, all patients with chondral defects, that were treated with MAST from April 1st to November 30th, 2009 were analyzed. The size and location of the chondral defects, method-associated problems and the Visual Analogue Scale Foot and Ankle (VAS FA) before treatment and at follow-up were registered and analyzed. RESULTS: Twenty-six chondral defects in 25 patients were included in the study. The mean age of the patients was 33 years (range, 16-48 years), 18 (72%) were male. The VAS FA before surgery was 49.2 on average (range, 24.3-68.4). The defects were located as follows: medial talar shoulder, n=9; lateral talar shoulder, n=13 (medial and lateral talar shoulder, n=1); distal tibia, n=1; posterior calcaneal facet, n=1; head of 1st metatarsal, n=2. The defect size was 1.1cm(2) on average (range, .5-6 cm(2)). All patients completed 2-year-followup. No complications or consecutive surgeries were registered. The mean VAS FA at follow-up was 94.5 (range, 73.4-100; t-test, p<.01). CONCLUSIONS: MAST led to good clinical scores. No complications were registered. Even though a control group is missing, we conclude that MAST is a safe and effective method for the treatment of chondral defects. The main advantage of MAST in comparison with ACI and MACI is the single procedure methodology. The advantage in comparison with AMIC is the potential higher concentration of stem cells.

Lengthening osteotomy of the calcaneus and flexor digitorum longus tendon transfer in flexible flatfoot deformity improves talo-1st metatarsal-Index, clinical outcome and pedographic parameter.

Lengthening osteotomy of the calcaneus (LO) and flexor digitorum longus tendon (FDL) transfer to the navicular is one option for the treatment of flexible flatfoot deformity (FD). The aim of the study was to analyse the amount of correction and clinical outcome including pedographic assessment. In a prospective consecutive non-controlled clinical followup study, all patients with FD that were treated with LO and FDL from September 1st 2006 to August 31st, 2009 were included. Assessment was performed before surgery and at 2-year-followup including clinical examination (with staging of posterior tibialis insufficiency) weight bearing radiographs (Talo-1st metatarsal angles (TMT)), pedography (increased midfoot contact area and force) and Visual Analogue Scale Foot and Ankle (VAS FA). 112 feet in 102 patients were analysed (age, 57.6 (13-82), 42% male). In 12 feet (9%) wound healing delay without further surgical measures was registered. All patients achieved full weight bearing during the 7th postoperative week. Until followup, revision surgery was done in 3 patients (fusion calcaneocuboid joint (n=2), correction triple arthrodesis (n=1)). 101 feet (90%) completed 2-year-followup. TMT dorsoplantar/lateral/Index and VAS FA scores were increased, and posterior tibialis insufficiency stage, pedographic midfoot contact area and force percentage were decreased (each p<.05). All relevant parameters (stage of posterior tibialis insufficiency, TMT angles and Index, pedographic midfoot contact area and force percentage, VAS FA) were improved 2 years after LO and FDL transfer to the navicular in FD. The complication rate was low. This method allows safe and predictable correction.

Four-stage regimen for operative treatment of diabetic foot ulcer with deformity - a results of 300 patients.

BACKGROUND: An operative four-stage regimen (stage 1, debridement; stage 2, closure; stage 3, unloading; stage 4, correction) for operative treatment of diabetic foot ulcer with deformity, and first clinical results are introduced. METHODS AND RESULTS: 335 patients entered stage 1 between 01/09/2006 and 31/08/2010. Stage 1: In 189 cases (56%), one debridement resulted in sterile postoperative specimens. Stage 2: 210 cases (63%) sustained secondary closure, 97 (29%) local shifted skin graft, and 20 (6%) functional amputation. Stage 3: 304 (90%) finished stage 3, 14 (4%) presented with recurrent ulcer. Stage 4: In 185 cases (55%), correction arthrodeses were performed successfully. FOLLOW-UP: 300 (90%) completed follow-up at 26months on average (12-48months). Recurrent ulcer was registered in 46 (15%). Overall amputation rate was 14%, the majority at digital or midfoot level. Four cases (1%) required a below-knee amputation. CONCLUSIONS: The management of diabetic foot ulcer combined with deformity with the introduced regimen showed low major amputation rate and low recurrent ulcer rate compared with the literature.