Swelling and pain is a frequent finding after hallux valgus correction. Aim of our study was to detect clinical differences in the initial postoperative period after minimally invasive chevron osteotomy (MIS) and the open chevron technique (OC). From the included patients clinical outcome was assessed preoperatively, and then at two, four, six and 12 weeks postopertively in terms of the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot Score, the Japanese Society for Surgery of the Foot (JSSF) metatarsophalangeal-interphalangeal Scale, the Maryland Foot Score (MFS), the SF12 Life Quality Scale, the Visual Analogue Scores (VAS) of pain, swelling of the foot, range of motion (ROM) and patient satisfaction. Radiographic parameters were taken preoperatively, as well as two, six and twelve weeks after surgery. The Charlson Comorbidity Index (CCI) was recorded preoperatively only, pain medication consumption was documented for the intial two weeks after surgery. Sixty-three feet were analyzed (33 MIS; 30 OC). Patient demographic characteristics and amount of the deformity in both groups did not differ significantly. Both techniques demonstrated good radiographic correction of the hallux deformity without superiority of one technique. We detected lower pain levels and reduced pain medication consumption as well as reduced swelling in the MIS group at the time points two, four and six weeks postoperatively. AOFAS score and the satisfaction score showed significantly better results in the MIS group as well. Minimally invasive chevron osteotomy shows better clinical ultra-shortterm outcome and lower pain levels in comparision to the open technique with comparable radiographic results.

BACKGROUND:The purpose of this study was to identify radiographic risk factors for loss of correction (LOC) after hallux valgus surgery and to weight their importance for LOC. METHODS:We retrospectively assessed the radiographs of 1,082 consecutive chevron osteotomy cases regarding early LOC from initially postoperative to 6 and 12 weeks postoperative. The influence of preoperative and postoperative radiographic parameters on LOC of the hallux valgus angle (HVA) and the intermetatarsal 1-2 angle (IMA) was evaluated using nonparametric Spearman rank correlations and multiple linear regression analyses. RESULTS:Mean ± SD LOC from initially postoperative to 6 and 12 weeks postoperative were 1.4° ± 2.7° and 3.4° ± 2.6° for the IMA and 3.5° ± 5.4° and 7.6° ± 5.6° for the HVA, respectively. Significant correlations were found between LOC of the HVA or IMA for preoperative IMA, HVA, distal metatarsal articular angle, proximal to distal phalangeal articular angle (PDPAA), and joint congruity as well as for postoperative IMA, HVA, PDPAA, joint congruity, and sesamoid position. Categorization of outcome-predicting postoperative radiographic factors revealed the following parameters to be important, in descending order: HVA, sesamoid position, IMA, PDPAA, and joint congruity. CONCLUSIONS:Multiple preoperative and postoperative radiographic parameters correlate with early LOC after hallux valgus surgery. Relevancy grading revealed the postoperative HVA and sesamoid position to be the most important parameters, followed by the IMA, PDPAA, and joint congruity. Consequently, total deformity correction, taking all aspects of the hallux valgus deformity into account, seems reasonable.

Pathologische Torsionen des Oberschenkels und Unterschenkels sind häufig. Die negativen Auswirkungen auf das Knie sind evident und betreffen nicht nur das Patellofemoralgelenk. Die Verdachtsdiagnose auf eine Maltorsion wird durch die physische Untersuchung generiert, und durch die Schichtbildgebung verifiziert (MRT oder CT). Das von den Autoren durchgeführte Literatur-Review zum Thema Derotationsosteotomien an der Tibia erbrachte 35 Studien (1562 Osteotomien). Fast alle Studien berichteten, auf Basis der „patient-reported outcomes“ (Kujala, SF-36, Lysholm, KOOS, VAS und generelle Patientenzufriedenheit), von einer deutlichen Verbesserung im Vergleich zu vor der Operation. Aufgrund des Fehlens von vergleichenden Studien ist bis dato die beste Operationstechnik für die tibiale Derotationsosteotomie noch unbestimmt. Für komplexe Fälle, bei welchen Deformitäten in mehreren Körperebenen korrigiert werden sollen (z. B. Maltorsion und Valgus-Varus-Deformität), scheint die dreidimensionale Planung und Umsetzung mittels patientenspezifischer Schnittblöcke vielversprechend.

Pathological torsions of the femur and tibia are common. The negative effects on the knee are evident and do not only affect the patellofemoral joint. The suspected diagnosis of maltorsion is generated by physical examination and verified by tomographic imaging (MRI or CT). The literature review regarding tibial derotation osteotomies conducted by the authors yielded 35 studies (1562 osteotomies). Almost all of the studies reported a significant improvement compared to preoperatively based on patient-reported outcomes (Kujala, SF-36, Lysholm, KOOS, VAS and general patient wellbeing). Due to the lack of comparative studies, the best surgical technique for tibial derotation osteotomy is still undetermined. For complex cases in which deformities in several body planes are to be corrected (e.g., maltorsion and valgus varus deformity), three-dimensional planning and implementation using patient-specific incision blocks seems promising.

BACKGROUND:Outcome reports for Alpha Ankle Arthroplasty (AAA), a third-generation implant relying on a mobile bearing design for total ankle replacement, are sparse. This retrospective study evaluated the midterm survivorship, clinical, and radiologic outcomes after implantation of this implant.METHODS:For 64 patients who received 65 Triple A ankle implants between 2009 and 2020, implant survival was calculated using the Kaplan-Meier curve. Clinical outcomes were evaluated by measuring the range of motion, stability, Western Ontario and McMaster Universities Osteoarthritis Questionnaire score (WOMAC), and American Orthopaedic Foot & Ankle Society ankle-hindfoot score (AOFAS). The average pain level and satisfaction with the postoperative result were rated on a numeric rating scale (0-10). Additionally, radiologic analysis was performed using anteroposterior and lateral radiographs and tibiotalar alignment was assessed.RESULTS:The implant-survival rate was 61.5% at a mean follow-up of 8.2 years. Twenty-five patients (38.5%) required revision surgery (average time to revision, 3.1 years, 95% CI 2.1-4.1 years). For patients without revisions, the average range of motion in dorsiflexion and plantarflexion were 3.6 ± 4.2 degrees and 21.9 ± 7.8 degrees, respectively. The mean WOMAC and AOFAS scores were 44.7 ± 47.5 and 75.1 ± 14.0, respectively. The average pain and subjective satisfaction scores were 2.0 ± 1.7 and 8.5 ± 1.9, respectively. Mean alignment values did not differ significantly for patients who required revision surgery.CONCLUSION:We found a high revision rate with use of the AAA. However, patients who did not require revision surgery had, on average, high satisfaction and good functional outcomes.LEVEL OF EVIDENCE:Level IV, case series.

Purpose Arthroplasty registries gained increasing importance to the re-certification of orthopaedic implants according to the European Union (EU) Medical Device Regulation (MDR) adopted in 2017. Until recently, several European countries only had regional arthroplasty registries. Whether regional registries deliver data quality comparable with national registries remained unclear. Therefore, the purpose of this study was to validate the Austrian Tyrolean Hip Arthroplasty Registry (THAR) and to evaluate if this regional registry showed adequate adherence, completeness and correctness when compared with well-established national registries. Methods A consecutive series of 1100 primary total hip arthroplasties were identified from our institution’s medical database. Patients were interviewed by phone and completed questionnaires after a mean follow-up period of 8.05 years and were asked if they had had revision surgeries. The data were compared to the corresponding dataset from the THAR. Results Adherence was 97.91% for primary total hip arthroplasty. Clinical follow-up identified 10 missing cases, resulting in adherence of 81.48% for revisions. Completeness of patient-reported outcome measurements was 78.55% before surgery and 84.45% 1 year after surgery. Correctness was 99.7% for demographic data, 99.54% for implant specifications, and 99.35% for mode of fixation. Conclusion The data of this study showed that regional arthroplasty registries can deliver data quality comparable with well-established national registries. The main reason for unrecorded revision cases and wrongly recoded implants was human error. Further digitalization with more automatic data submission may have the potential to reduce these failure rates in the future. Overall, the THAR represents a valid data source for re-certification of medical implants according to the EU’s MDR.

Objectives: Injuries on alpine ski slopes have been described in cohorts of a reasonable sample size, but constant improvements in safety gear, increased use of airborne rescue, and safety measures during the coronavirus disease 2019 (COVID-19) pandemic mandate re-evaluation. Therefore, the purpose of this study was to evaluate skiing and snowboarding injuries, effectiveness of airborne rescue, and impact of the COVID-19 pandemic on a large sample size. Methods: Data on alpine injuries were prospectively collected from the state emergency services dispatch center in the state of Tyrol (Austria). A total of 10,143 patients were identified, with an average age of 33.5 years (SD = 20.36). The ski patrol was involved in 8,606 cases (84.9%) and some patients (n = 1,536; 15.1%) required helicopter rescue. Results: A total of 10,143 patients were identified from the dataset of the emergency dispatch center. The most frequently injured region was the knee (30.2%), and it was followed by the shoulder (12.9%), the lower leg (9.5%), and the head/skull (9.5%). Conclusion: The present findings indicate that the most frequent site of injuries on alpine slopes is the knee, and life-threatening injuries are rare. Airborne rescue is very time-effective, however clinical studies with patient follow-up should be emphasized to determine the impact of airborne rescue on patient outcome. The present findings indicate that the duration of all rescue operations has been prolonged as a result of the introduction of safety measures during the COVID-19 pandemic.

Primary total hip arthroplasty with cementless stems has numerous advantages over cemented total hip arthroplasty in patients with good bone quality. To enhance osseointegration with ingrowth into the implant, various surface treatments have been proposed. Multiple biomechanical studies in animals have shown that bioactive coatings enhance osseointegration and increase construct stability. Bony ingrowth in humans can only be assessed in rare instances of periprosthetic femoral fractures. In this case report, we describe the findings after a periprosthetic fracture mandating stem exchange in a patient who experienced a fall 8 weeks after implantation. The retrieved proximal Bonit (DOT GmbH, Rostock, Germany) coated stem showed substantial macroscopically visible trabecular bone. This finding supports results from animal studies that showed enhanced metaphyseal bone ingrowth with Bonit coating of implants.

Objective Clinical and radiographic analysis of a minimally invasive arthrodesis technique of the first metatarsophalangeal joint. Indications Symptomatic hallux rigidus, symptomatic hallux rigido-valgus, hallux varus. Contraindications Absolute contraindication (CI): osteomyelitis; relative CI: untreated diabetes mellitus, smoking. Surgical technique Under arthroscopic assistance, a minimally invasive arthrodesis technique of the first metatarsophalangeal joint is performed with removal of the subchondral sclerosis and remaining cartilage of the osteoarthritic joint. Postoperative management Immediate weight-bearing starts on day 1 using a ready-made hallux valgus shoe for 6 weeks. Physiotherapy without movement of the first metatarsophalangeal joint is allowed after surgery. Results A series of 5 patients with symptomatic hallux rigidus and relevant medical diseases were evaluated after minimally invasive arthroscopic arthrodesis of the first metatarsophalangeal joint. In all cases osseous union was found after 8.4 months. Follow-up was 22.6 months and the American Orthopedic Foot and Ankle Society (AOFAS) score increased significantly from 42.4 to 82.8 points. No complications requiring therapy were observed in our cohort nor was revision surgery necessary. The results of our series are in line with the published results of minimally invasive fusion techniques of the first metatarsophalangeal joint.

Introduction: The Chiari pelvic osteotomy (CPO) has been recommended as a salvage procedure to improve head coverage in case of hip joint incongruence in paediatric hip disease. In this study, we aimed to assess the long-term results of CPO for severe Legg-Calve-Perthes disease (LCPD). Methods: A total of 39 patients who underwent a CPO at our department between 1995 and 2010 were prospectively followed both radiologically (Stulberg classification) and clinically (Harris Hip Score [HHS], conversion into total hip arthroplasty). In this study, we retrospectively reviewed the cases of 12 hips (12 patients, 3 girls, 8 left hips) treated by CPO for severe LCPD (Catterall grade 3 or 4) with hip joint incongruence. Mean follow-up was 14.0 (range 7.6-21.3) years. Results: Mean age at surgery was 10.2 (range 8.2-17.8) years. Additional femoral osteotomy was performed in 8 patients. A good radiological result (Stulberg I or II) was achieved in 2 patients, a fair result (Stulberg III) in 4 patients, and a poor outcome (Stulberg IV or V) in 6 patients. Mean postoperative HHS averaged 93 (range 65-100) points. An excellent functional outcome (HHS 90-100 points) was achieved in 9 patients. No patient underwent total hip arthroplasty during follow-up. Postoperative limb-length discrepancy was found in 3 patients. Conclusions: CPO for severe LCPD with hip joint incongruence resulted in good long-term clinical outcome in about ? of our patients after a mean of 14 years. Our results suggest that CPO can still be considered as a salvage joint-conserving procedure in this selected group of younger patients.

Background: The newly described anteroposterior "off-axis view" (OAV) radiograph might help detect a hallux valgus interphalangeus (HVI) deformity more precisely compared to anteroposterior standing radiographs. Methods: A radiographic assessment of HVI angles was performed using preoperative standing anteroposterior and OAV radiographs for 67 ft. Intra-and interobserver agreement for all angles and their correlation with HV severity were analyzed. Results: The proximal-to-distal phalangeal articular angle showed less intra-and interobserver variance (intraclass correlation coefficient: 0.825) than did the other angles. OAV radiographs showed less interobserver reliability than did standing radiographs. HVI was underestimated significantly, by up to 5 degrees, on standing radiographs compared to OAV radiographs (p < 0.001). The mean differences between OAV and standing radiographs were 3.7 degrees and 5.0 degrees for the proximal-to-distal phalangeal articular and hallux interphalangeal angles, respectively, and were more pronounced for moderate-to-severe HV deformities. Conclusion: Angular measurements of HVI on traditional anteroposterior standing radiographs are significantly smaller than on OAV radiographs. Furthermore, angular measurements on OAV radiographs are associated with higher interobserver reliability. The most precise angle representing an HVI deformity might be the proximal-to-distal phalangeal articular angle. Clinical Relevance: Our findings may facilitate preoperative decision-making for additional akin osteotomy in HV correction. (C) 2020 Published by Elsevier Ltd on behalf of European Foot and Ankle Society.

BACKGROUND/AIM:To date, multiple different surgical techniques have been established for hallux valgus surgery, with each technique having its unique advantages and limitations. The open distal chevron osteotomy is widely accepted, but increasing patient demands have led several minimally invasive (MIS) techniques to be described in recent years. The aim of this study was to compare outcomes after minimally invasive (MIS) distal chevron osteotomy and the minimally invasive Reverdin-Isham method. PATIENTS AND METHODS:We assessed clinical and radiographic outcomes after MIS chevron osteotomy in 57 feet of 49 consecutive patients with a mean follow-up of 58.9 (range=39.0-85.4) months. Outcomes after MIS Reverdin-Isham osteotomy were analyzed by means of a systematic literature review with a minimum follow-up of 6 months. RESULTS:Radiographic outcomes were significantly better in the MIS chevron cohort for intermetatarsal angle (p<0.001), hallux valgus angle and distal metacarpal articular angle (p<0.05). Concerning clinical outcomes, both methods provided comparable improvement. CONCLUSION:MIS distal chevron osteotomy in mild to moderate hallux valgus deformity correction results in superior radiographic outcomes compared to the MIS Reverdin-Isham osteotomy. Sufficient correction of IMA cannot be achieved with the MIS Reverdin-Isham osteotomy.

Erreichen einer stabilen Fusion des MTP(Metatarsophalangeal)-1-Gelenks mittels minimal-invasiver Arthrodesetechnik. Symptomatischer Hallux rigidus, symptomatischer Hallux rigido-valgus, Hallux varus. Absolute KI: Osteomyelitis. Relative KI: unbehandelter bzw. entgleister Diabetes mellitus, Nikotinabusus. Unter arthroskopischer Kontrolle Durchführung der Restknorpelentfernung und Anfrischung der subchondralen Skleroseschicht. Perkutane Verschraubung unter Bildwandlerkontrolle. Postoperativ für 6 Wochen eine Verbandssandale mit steifer Sohle, Lymphdrainagen ab dem ersten postoperativen Tag. Anhand einer Serie von 5 Patienten mit symptomatischem Hallux rigidus und schwerwiegenden Vorerkrankungen wurde in allen Fällen eine stabile knöcherne Fusion nach 8,4 Monaten beobachtet. Das mittlere Follow-up betrug 22,6 Monate und zeigte eine signifikante Verbesserung des AOFAS-Scores von 42,4 auf 82,8 Punkte auf. Es wurden in dieser Patientenkohorte weder therapiebedürftige Komplikationen beobachtet noch wurde eine Revisionsoperation notwendig. Die Ergebnisse dieser Patientenkohorte decken sich mit den in der Literatur publizierten Resultaten nach minimal-invasiven Arthrodeseoperationen am Großzehengrundgelenk.

Loss of correction is frequently observed following hallux valgus correction and is associated with recurrence of a hallux valgus deformity. The purpose of this study was to correlate loss of correction and radiological parameters following distal chevron (Group C) and combined chevron/akin (Group AC) osteotomy. A total of 859 feet were included for analysis and grouped according to treatment with a distal chevron osteotomy alone or a combined chevron/akin osteotomy. Radiographs were evaluated preoperatively, postoperatively, after 6 weeks, 3 months and, if available, at long term follow-up with a mean of 34.2 (range 7.5-155.3) months. With the exception of the proximal to distal phalangeal articular angle (PDPAA), preoperative deformity was comparable between both groups. Significant correction of all examined parameters (p < .001) was seen. Loss of correction at 6 weeks with minor deterioration until follow-up was also detected, with group AC somewhat better than Group C. A strong correlation with loss of correction was found for the postoperative hallux valgus angle (HVA) (p < .002), intermetatarsal angle (IMA) (p < .001), distal metatarsal articular angle (DMAA) (p < .002), positioning of the sesamoids (p < .002) and joint congruity (p < .035) in Group C and for the DMAA (p < .033) and HVA (p < .046) in Group AC. Multiple postoperative radiological parameters correlated with loss of correction following distal chevron osteotomy. In Group AC only postoperative HVA and DMAA determined loss of correction. Correction of the deformity in Group AC showed greater stability.

BACKGROUND The aim of the present prospective randomized study was to evaluate the long-term outcomes of minimally invasive chevron osteotomy as compared with open distal chevron osteotomy for the correction of hallux valgus deformity. METHODS A randomized controlled design was applied. The following parameters were assessed at 6 and 12 weeks, 9 months, and 5 years postoperatively: the American Orthopaedic Foot & Ankle Society (AOFAS) Forefoot Score, a visual analog scale (VAS) score for pain, and a patient-satisfaction score. In addition, several radiographic parameters for hallux valgus correction and joint degeneration were collected. Range of motion was also assessed. Thirty-nine of 47 feet were available for analysis at the time of the latest follow-up. RESULTS During the 5-year study period, the outcomes of the minimally invasive technique were comparable with those of the open technique. No significant differences were seen between the 2 groups within 5 years postoperatively in terms of clinical outcomes (VAS, AOFAS, satisfaction), radiographic outcomes, joint degeneration, or range of motion. CONCLUSIONS Five years after treatment, the outcome following minimally invasive distal chevron osteotomy is comparable with that for the open technique for hallux valgus surgery. LEVELS OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Scarf osteotomy is a frequently used technique to correct moderate to severe hallux valgus deformities. Recurrence of a deformity is a commonly reported complication after surgery. The aim of our study was to evaluate the impact of preoperative deformity on radiological outcome in terms of postoperative loss of correction after scarf osteotomy.METHODS:102 patients, in which a hallux valgus deformity was corrected with an isolated scarf osteotomy were included. Weightbearing radiographs were analyzed preoperatively, postoperatively, after 6 weeks and after three months (mean 10.9 months SD 17.2 months). The following radiological parameters were used for analysis: the intermetatarsal angle (IMA), the hallux valgus angle (HVA), the distal metatarsal articular angle (DMAA), position of the sesamoids, first metatarsal length, and first metatarsophalangeal joint congruity.RESULTS:Significant correction of IMA, HVA, DMAA, sesamoid position and joint congruity was achieved (p < 0.001). The IMA improved from 15.8 ± 2.3 to 4.3 ± 2.8°, the HVA from 32.6 ± 6.8 to 9.1 ± 7.2, and the DMAA from 11.4 ± 6.9 to 8.4 ± 5.2°, respectively. In contrast to DMAA, throughout followup we could detect loss of correction for HVA and for IMA amounting 6.3° ± 5.8 and 3.8° ± 2.8 respectively. Loss of HVA correction revealed a significant correlation with preoperative DMAA, but not with the other preoperative radiological parameters.CONCLUSIONS:Preoperative deformity does not correlate with postoperative loss of correction after scarf osteotomy, except DMAA.CLINICAL RELEVANCE:Our results may be helpful in counseling patients regarding recurrence of hallux valgus deformity after scarf osteotomy.LEVEL OF EVIDENCE:Therapeutic, Level IV, retrospective case series.

The Chevron osteotomy is a frequently used surgical method for hallux valgus correction. This method is often combined with an Akin osteotomy. To date, clear guidelines for the implementation of an additional Akin osteotomy are missing. The purpose of this study was to elucidate the impact of concomitant phalangeal correction on the outcome after hallux valgus surgery and to define indication criteria for an additional Akin osteotomy. Patients (859 feet) undergoing distal Chevron osteotomy at our department were retrospectively grouped into group C (Chevron, 785 feet) and group AC (Chevron plus Akin, 74 ft). Radiological assessment including the intermetatarsal angle (IMA), the hallux valgus angle (HVA), the distal metatarsal articular angle (DMAA), and the proximal to distal phalangeal articular angle (PDPAA) was performed preoperatively, postoperatively, after 6 weeks, and after 3 months. Longer-term follow-up with a mean of 36.4 months was available for 248 cases (29%). A significant improvement of all parameters could be found to all points of survey (p < 0.001). Loss of correction was detected for HVA (p < 0.001) and IMA (p < 0.007) with higher levels in group C. Preoperative PDPAA exceeding 8° correlated significantly with loss of HVA correction in group C (p < 0.001). The combined Chevron and Akin osteotomy allowed for better correction of the hallux valgus deformity with better maintenance of the achieved correction. Recommendation for concomitant Akin osteotomy may be determined by a preoperative PDPAA exceeding 8°. Retrospectively registered. UN5080 . Therapeutic, Level III, retrospective comparative series.

Background: Recurrence is relatively common after surgical correction of hallux valgus. Multiple factors are discussed that could have an influence in the loss of correction. The aim of this study was to determine preoperative radiological factors with an influence on loss of correction after distal chevron osteotomy for hallux valgus. Methods: Five hundred twenty-four patients who underwent the correction of a hallux valgus by means of distal chevron osteotomy at our institution between 2002 and 2012 were included. We assessed weightbearing x-rays at 4 time points: preoperatively, postoperatively, and after 6 weeks and 3 months. We investigated the intermetatarsal angle (IMA), the hallux valgus angle (HVA), the distal metatarsal articular angle (DMAA), joint congruity, and the position of the sesamoids. Results: At all points of the survey, significant correction of the IMA and HVA was detected. The IMA improved from 12.9 (± 2.8) to 4.5 (± 2.4) degrees and the HVA from 27.5 (± 6.9) to 9.1 (± 5.3) degrees. Loss of correction was found in both HVA and IMA during follow-up with a mean of 4.5 and 1.9 degrees, respectively. Loss of correction showed a linear correlation with preoperative IMA and HVA, and a correlation between preoperative DMAA and sesamoid position. Conclusion: The chevron osteotomy showed significant correction for HVA, IMA, and DMAA. Preoperative deformity, in terms of IMA, HVA, DMAA, and sesamoid position, correlated with the loss of correction and could be assessed preoperatively for HVA and IMA. Loss of correction at 3 months persisted during the follow-up period. Level of Evidence: Level IV, retrospective case series.

The scarf osteotomy is a well-established surgical method for correcting a hallux valgus deformity. It is often combined with an Akin osteotomy. However, clear guidelines defining indication criteria are missing. The purpose of this study was to analyze the radiological outcome after scarf osteotomy in dependence of additional Akin osteotomy. This study included 184 patients in whom a hallux valgus deformity was corrected with a scarf osteotomy (group S), and 63 patients in whom an additional Akin osteotomy was performed (group SA). Weight-bearing radiographs were evaluated preoperatively, postoperatively, after 6 weeks, after 3 months and at a follow-up with a mean of 45.4 months. Analysis was made for the following radiological parameters: the intermetatarsal angle (IMA), the hallux valgus angle (HVA), the distal metatarsal articular angle (DMAA), the proximal to distal phalangeal articular angle (PDPAA), and the position of the sesamoids as well as the joint congruity. Radiographic recurrence (HVA > 20°) was detected in 1 patient (1.6% of recurrence) in the SA group, and in 27 patients in the S group (14.7% of recurrence) at follow-up. Outcome between the two groups differed significantly showing reduced loss of HVA correction in the SA group (p < 0.001). The subgroup with a preoperative PDPAA above eight degrees showed significant inferiority of outcome for the S group compared to the SA group. Radiological outcome after scarf osteotomy is superior with concomitant Akin osteotomy. A preoperative PDPAA above eight degrees makes additional Akin osteotomy recommendable. Therapeutic, Level III, retrospective comparative series

BackgroundBone defects can be filled with autografts, allografts and artificial bone-materials. The aim of this study was to evaluate whether the digitization of known defect models with a navigation system is a reliable measurement method for estimating the size of a bone defect.MethodsSix preformed, cylindrical and cone-shaped defects on an artificial hip-bone were digitalized by six different observers. Reference volumes were gathered by measuring the depth of the defects, using an alginate impression material to fill out the defects and calculating the volumes from a CT scan.ResultsOne out of the six preformed defects showed a statistically significant difference between the digitalization and the calculation, four showed a significant difference between the digitalization and the mould as well as between the digitalization and the CT calculation.ConclusionsThis technique offers satisfactory results and consistent reproducibility when digitalizing big defects with relatively simple shape. Decreasing size and increasing complexity of the defects leads to more imprecise measurements.