Functional, Spiroergometric, and Subjective Comparisons Between Forearm Crutches and Hands-Free Single Crutches in a Crossover Study.

Background: Following below-knee surgery, the optimal medical mobility device remains controversial as adequate nonweightbearing of the operated extremity is critical to ensure successful healing. The use of forearm crutches (FACs) is well established but requires using both upper extremities. The hands-free single orthosis (HFSO) is an alternative that spares the upper extremities. This pilot study compared functional, spiroergometric, and subjective parameters between HFSO and FAC. Methods: Ten healthy (5 females, 5 males) participants were asked to use HFSOs and FACs in a randomized order. Five functional tests were performed: climbing stairs (CS), an L-shaped indoor course (IC), an outdoor course (OC), a 10-meter walk test (10MWT), and a 6-minute walk test (6MWT). Tripping events were counted while performing IC, OC, and 6MWT. Spiroergometric measurements consisted of a 2-step treadmill test with speeds of 1.5 and 2 km/h, each for 3 minutes. Lastly, a VAS questionnaire was completed to collect data regarding comfort, safety, pain, and recommendations. Results: Significant differences between both aids were observed in CS and IC (HFSO: 29.3 seconds; FAC: 26.1 seconds, P < .03; and HFSO: 33.2 seconds, FAC: 18 seconds, P < .001, respectively). The other functional tests showed no significant differences. The trip events were not significantly different between the use of the 2 aids. Spiroergometric tests showed significant differences regarding heart rate (HFSO: 131.1 bpm at 1.5 km/h and 131 bpm at 2 km/h; FAC: 148.1 bpm at 1.5 km/h and 161.8 bpm at 2 km/h) and oxygen consumption (HFSO: 15.4 mL/min/kg at 1.5 km/h and 16 mL/min/kg at 2 km/h; FAC: 18.3 mL/min/kg at 1.5 km/h and 21.9 mL/min/kg at 2 km/h) at both speeds (all P < .01). In addition, significantly different ratings regarding the items comfort, pain, and recommendation were recorded. Both aids were equally rated for safety. Conclusion: HFSOs may be an alternative to FACs, especially in activities that require physical stamina. Further prospective studies in patients with below-knee surgical intervention concerning everyday clinical use would be interesting. Level of Evidence: Level IV pilot-study.

Establishing a New Patient-Specific Implantation Technique for Total Ankle Replacement: An In Vitro Study.

BACKGROUND: Revision rates after total ankle replacements (TARs) are higher compared with other total joint replacements. The present study aimed to establish a new patient-specific implantation (PSI) technique for TAR. MATERIAL AND METHODS: A total of 10 complete Caucasian cadaver legs had whole leg computed tomography scans. The individual geometrical ankle joint axis was determined, and based on this axis, the position of the prosthesis was planned. We assessed prosthesis placement, guiding block position, and preoperative and postoperative ankle rotational axes. RESULTS: The guiding block position interobserver reliability was 0.37 mm 0.45 (mean ± SD) for the tibial guiding block. The value for the first talar guiding block was 1.72 ± 1.3 mm and for the second talar guiding block, 0.61 ± 0.39 mm. The tibial slope as well as the frontal angles of the anatomical tibial axis compared to the tibial and talar articular surfaces showed no statistically relevant differences with numbers available. The deviation of the assessed preoperative joint axis to the postoperative joint axis was 14.6° ± 7.8. CONCLUSION: The present study describes the results of an establishing process of a new PSI technique for TAR. The reliability of guiding block positioning and, thereby, prosthesis placement is sufficient. LEVEL OF EVIDENCE: Biomechanical study.

[Diagnosis and Therapy of Acute Achilles Tendon Ruptures]. / Diagnose und Therapie der akuten Achillessehnenruptur.

Diagnosis and Therapy of Acute Achilles Tendon Ruptures Abstract. Acute Achilles tendon ruptures are a common pathology and often affect young athletic patients. Diagnosis is mostly clinical and by ultrasound. Conservative and operative treatment algorithms exist. The result of the treatment is mostly influenced by the elongation of the tendon during healing. Operative procedures tend to lead to less elongation but have a complication risk. After-treatment should be functional to reduce complication rate and faster rehabilitation. Treatment results are good in general, but some weakness is often found on the injured side.

Foot and Ankle Surgical Incision Closure With Three Different Materials.

There is no clear recommendation for wound closure material in foot and ankle surgery. Thus, we hypothesized that there was no difference in clinical outcomes among 3 suture materials, namely, absorbable sutures, nonabsorbable sutures, and metallic staples. This study compared the 3 materials for wound closure in foot and ankle surgery. In this prospective randomized study, 124 patients were randomly divided into the nonabsorbable suture group, absorbable suture group, and staple group. ASEPSIS score, Hollander Wound Evaluation Scale, and numerical rating scale (regarding pain and satisfaction) were collected at first dressing changes, suture removal, and 6 weeks after surgery. Suture time and incision length were recorded. No significant differences were detected for the ASEPSIS and Hollander Wound Evaluation Scale scores. There was significantly more pain after 6 weeks in the nonabsorbable suture group. The closure time (13 s/cm) with staples was significantly lower in the nonabsorbable suture group than in the other groups. Regardless of wound closure material, male sex and obesity appeared to be associated with a higher risk for the occurrence of wound complications. The 3 suture materials showed no significant differences regarding the frequency of wound complications. Staples and absorbable sutures should therefore be considered in the repertoire of suture materials used in foot and ankle surgery.

[Conversion osteotomy for arthrosis of the ankle joint (supramalleolar and inframalleolar)-What can be expected? : Critical review of the literature]. / Umstellungsosteotomien bei Arthrose am Sprunggelenk (supra- und inframalleolar) ­ Was kann man erwarten? : Kritische Übersicht der Literatur.

The aim of supramalleolar conversion osteotomy is to reduce the pain of the patient and stop or at least slow down joint degeneration. The indication for supramalleolar osteotomy is asymmetric osteoarthritis of the ankle joint with varus or valgus deformity. Good clinical results for arthritis can be achieved in the early or middle stages. Besides closing and opening wedge osteotomies dome osteotomy is sometimes indicated, especially for larger deformities. The preoperative preparation of individual patient-specific section blocks facilitates the intraoperative implementation and seems to increase the precision. Further studies are necessary to support this. The indications for additional procedures, such as fibular osteotomy are still being discussed. Inframalleolar osteotomy and soft tissue interventions are frequently necessary for balancing the foot.

Biomechanical Evaluation of Tarsometatarsal Fusion Comparing Crossing Lag Screws and Lag Screw With Locking Plate.

BACKGROUND: Tarsometatarsal (TMT) arthrodesis is a common operative procedure for end-stage arthritis of the TMT joints. To date, there is no consensus on the best fixation technique for TMT arthrodesis and which joints should be included. METHODS: Thirty fresh-frozen feet were divided into one group (15 feet) in which TMT joints I-III were fused with a lag screw and locking plate and a second group (15 feet) in which TMT joints I-III were fused with 2 crossing lag screws. The arthrodesis was performed stepwise with evaluation of mobility between the metatarsal and cuneiform bones after every application or removal of a lag screw or locking plate. RESULTS: Isolated lag-screw arthrodesis of the TMT I-III joints led to significantly increased stability in every joint (P < .05). Additional application of a locking plate caused further stability in every TMT joint (P < .05). An additional crossed lag screw did not significantly increase rigidity of the TMT II and III joints (P > .05). An IM screw did not influence the stability of the fused TMT joints. For TMT III arthrodesis, lag-screw and locking plate constructs were superior to crossed lag-screw fixation (P < .05). TMT I fusion does not support stability after TMT II and III arthrodesis. CONCLUSION: Each fixation technique provided sufficient stabilization of the TMT joints. Use of a lag screw plus locking plate might be superior to crossed screw fixation. An additional TMT I and/or III arthrodesis did not increase stability of an isolated TMT II arthrodesis. CLINICAL RELEVANCE: We report the first biomechanical evaluation of TMT I-III arthrodesis. Our results may help surgeons to choose among osteosynthesis techniques and which joints to include in performing arthrodesis of TMT I-III joints.

The Ankle Spacer-a hemiarthroplasty for treatment of severe osteochondral defects of the talus.

OBJECTIVE: The Ankle Spacer system has been developed as a joint-preserving option for patients with failed treatment of large talar osteochondral defects (OCDs). It is a one-piece implant system that replaces the articulating upper talus surface of the tibiotalar joint. INDICATIONS: Large OCDs with failed prior surgical intervention(s) and/or multiple talar OCDs on the talar surface, posttraumatic or degenerative osteoarthritis, or avascular necrosis of the talus. CONTRAINDICATIONS: Severe malalignment exceeding 7° and other ankle deformities that would not allow proper rasping of the talus, obesity, blood supply limitations, severe osteopenia, and previous or active infections. SURGICAL TECHNIQUE: The surgery is carried out via a central approach to the ankle joint. The tibiotalar joint was distracted to remove the cartilage on the upper talar surface with special talus rasps and to perform microfracture of the entire talar surface. The appropriate Ankle Spacer trial was then inserted into the joint and fluoroscopy was used to check for proper trial size and positioning. After thorough cleaning of the prepared bone bed, the Ankle Spacer was inserted with a special seating instrument. POSTOPERATIVE MANAGEMENT: One surgeon in our center implanted ten Ankle Spacers between April 2018 and October 2019. The first short-term data with follow-up of 3 months were collated. RESULTS: No implant-related complications were recorded. American Orthopaedic Foot and Ankle Society (AOFAS) score increased from 55.5 to 79.5 points, European Foot and Ankle Society (EFAS) score increased from 5.6 to 13.5 points, and pain score decreased from 3 to 1.1 points. None of the patients' radiographs showed signs of loosening or osteoarthritis progression.

Erratum: The computed tomography based anatomy of the ossa cuneiformia.

There is a lack of basic anatomic informations regarding the ossa cuneiformia. The aim of the present descriptive study was the detailed evaluation of the anatomy of the ossa cuneiformia. We analyzed 100 computer tomography scans of feet without deformities or previous trauma. The length, height and width of each cuneiforme and their articular surfaces were assessed. We itemized the data to gender differences and to foot length. The medial cuneiforme os had a length of 23.8±2.4 mm (mean ± standard deviation), a width of 15.9±2.7 mm and a height of 26.9±3.6 mm. The respective values for the intermediate cuneiforme were 17.7±1.9 mm, 12.4±3.1 mm and 20.8±2.9 mm and for the lateral cuneiforme 24.3±2.9 mm, 14.9±2.9 mm and 17.3±4.3 mm. We found statistical relevant differences regarding gender and foot length subgroups whereas not for all parameters. The present study illustrates basic anatomic data regarding the ossa cuneiformia. This information might be helpful for implant design and placement during midfoot surgery.

Comparison of Isolated Screw to Plate and Screw Fixation for Tarsometatarsal Arthrodesis Including Clinical Outcome Predictors.

BACKGROUND: The common treatment for end-stage tarsometatarsal (TMT) arthritis is an arthrodesis of the affected joints. This study was performed to examine the clinical and radiographic outcome after TMT arthrodesis and to identify risk factors for postoperative complications. METHODS: A total of 101 patients with tarsometatarsal arthritis of at least 2 joints were retrospectively examined. Data were acquired using clinical and radiographic examination, pedobarographic analysis, and standardized questionnaires, including the European Foot and Ankle Society Score, the Foot and Ankle Outcome Score, a pain numeric rating scale (NRS), the 36-Item Short Form Health Survey, and the University of California at Los Angeles Activity (UCLA) Score. The fixation technique, any complications, and revision surgery were recorded. RESULTS: All scores improved significantly, except for the UCLA Score. The mean pain NRS score was significantly reduced from 7.7 preoperative to 3.0 postoperative (P < .05). The overall nonunion rate was 12.6%. Compared with 2 crossed-screw fixation, locking plate plus compression screw fixation was associated with a decreased nonunion rate (odds ratio [OR] 0.165, 95% confidence interval [CI] 0.032-0.854; P = .017). A body mass index >27 was significantly associated with a higher nonunion rate and wound healing problems (OR 12.05, 95% CI 1.430-101.468; P = .006; OR 5.03, 95% CI 1.273-19.871; P = .013). The overall reoperation rate was 25.2%. CONCLUSION: TMT arthrodesis of the medial and central column resulted in significant improvement in foot function and pain. A major complication was nonunion. Locking plate plus compression screw fixation was associated with a lower nonunion rate. LEVEL OF EVIDENCE: Level III, comparative series.

Biomechanical evaluation of naviculocuneiform fixation with lag screw and locking plates.

BACKGROUND: There have been no biomechanical evaluations of naviculocuneiform (NC) joint fixation. This study compared biomechanically 3 different fixation constructs for NC-1-3 joint fixation. METHODS: The present study compared the three fixation constructs lag screw with locking plate for each NC joint, two crossed lag screws for each NC joint and a separate lag screw for each NC joint with bridging locking plates. NC-1-3 fixation was performed stepwise, and rotation of each joint was evaluated after the application of each lag screw or locking plate and their removal. RESULTS: All examined fixation techniques led to a significant reduced rotation of the NC joints. For NC-1 rotation decreased from 2.8° (Range 1.2-6.6°) to 0.6° (0.2-3.0°) for lag screw and locking plate (p = 0.002) and from 5.0° (1.7-9.8°) to 1.0° (0.1-3.6°) for crossed lag screws (p = 0.002). For NC-2, locking plate constructs were better with 0.2° (0.1-0.5°) compared to crossed lag screw osteosynthesis with 0.9° (0.2-1.6°) (p = 0.011). CONCLUSION: Each evaluated fixation technique led to a reduced NC joint rotation. The fixation of any NC joint had no relevant effect on the adjacent NC joints. The results might support surgeons treating NC joint disorders.

[Mini implants in foot and ankle surgery: an alternative to total joint replacement or joint fusion]. / Mini-Implantate am Fuß- und Sprunggelenk: Eine Alternative zur Vollprothese oder Versteifung.

Mini implants are increasingly used in foot and ankle surgery. They preserve the joints' functions, are easy to insert and easy to convert to an alternative treatment. Early surgical attempts using silastic implants did not bring the expected success. First achievements where reached with modern metallic mini implants in the first metatarsophalangeal (MTP) joint and the ankle joint. For a few years now, a polyvinyl alcohol implant has been used to treat the arthritic first MTP joint. Even severe arthritic joints can be treated with an implant made of polylactide. This implant can also be used in the treatment of Lisfranc joint pathologies. To address severe osteochondral defects of the talus, an innovative hemiarthroplasty implant has been suggested. This article gives a summary of currently used mini implants. Their application as possible alternatives to total joint replacement or joint fusion are critically reviewed in the light of the current literature.

Risk Analysis of Nonunion After First Metatarsophalangeal Joint Arthrodesis.

Objective: The standard therapy for a symptomatic hallux rigidus is still the arthrodesis of the first metatarsophalangeal (MTP) joint. A nonunion of the arthrodesis is a possible postoperative complication. This study aimed to evaluate the incidence of nonunion associated with first MTP joint arthrodesis and identify risk factors influencing this. Methods: This retrospective study included 197 patients who were treated with an isolated first MTP joint arthrodesis. The severity of MTP-related osteoarthritis was assessed clinically and radiologically prior to surgery according to the Waizy classification. Patient characteristics and radiological parameters were evaluated postoperatively. Results: A full clinical and radiological data set was collected from 153 out of 197 patients. We identified 14 cases of nonunion and found that nonunion was associated with higher incidence of male gender (P = .29), comorbidity (P = .035), higher grade of osteoarthritis (P = .01), and increased postoperative great toe dorsiflexion (P = .022). Conclusions: Arthrodesis of the first MTP joint is a safe operative treatment, as demonstrated by a nonunion rate of 9.2%. Negative influencing factors were the presence of preexisting diseases, higher grades of osteoarthritis, and a relative increased dorsiflexion position of the great toe after surgery. These factors should be considered during pre-, intra-, and postoperative planning.Levels of Evidence: Therapeutic, Level IV: Retrospective.

Feasibility and reliability of DEXA analysis after total ankle arthroplasty: A cadaver study.

BACKGROUND: Although the outcomes of total ankle arthroplasty (TAA) have improved, unsolved problems such as stress shielding remain. Although dual energy X-ray absorptiometry (DEXA) is the "gold standard" for evaluation of these issues, it is rarely used in patients after TAA. This study aimed to establish a scan technique and to assess the mechanical changes in bone density caused by bone stock preparation. METHODS: Eight fresh-frozen cadaver legs were investigated by DEXA before TAA, with implant in situ, and after implant removal. Scan surface, bone mineral content, and bone mineral density were analysed to assess mechanical bone mass changes. RESULTS: We examined data for density changes by bone compression after TAA, and found "good" results for internal reliability but only "acceptable" results for external reliability. CONCLUSIONS: The results were reliable and reproducible. Using the present data, mechanical and biological processes can be considered together to understand the postoperative phases of bone remodelling after TAA.

Treatment concepts for pes valgoplanus with concomitant changes of the ankle joint : Tibiotalocalcaneal arthrodesis, total ankle replacement and joint-preserving surgery.

Concomitant valgus deformities of the ankle joint are found in approximately 3% of patients with symptomatic flat foot deformities. Conservative treatment is mostly successful only in the short term or in low-demand patients. The operative treatment of flat foot deformities follows the standard algorithm for flat foot treatment. The ankle joint can be treated while retaining mobility or by arthrodesis depending on the degree and rigidity of the deformity, degenerative changes, patient factors and expectations. Achieving an orthograde hindfoot and midfoot is obligatory for successful treatment as well as in ankle reconstructive or arthrodesis procedures.

Manipulation under anesthesia as a therapy option for postoperative knee stiffness: a retrospective matched-pair analysis.

INTRODUCTION: Due to demographic changes, total knee arthroplasty (TKA) is one of the most frequently performed orthopedic surgeries. Therapies for associated postoperative complications, such as postoperative knee stiffness (PKS), are becoming increasingly important. The aim of this retrospective matched-pair analysis was to evaluate mid-term-results following manipulation under anesthesia (MUA). MATERIALS AND METHODS: Fifty-one patients with PKS were evaluated and 51 matched-pair patients without PKS after primary TKA were chosen for the control group. In addition to the range of motion, the functionality was recorded by Knee Society Score (KSS), Western Ontario and Mc Masters Universities Osteoarthritis Index (WOMAC), and Short-Form-12 Questionnaire (SF-12). Experience of pain was mapped using a 10-point Numeric Rating Scale (NRS), and the analgesic requirement was mapped using the WHO step scheme. A final follow-up examination was conducted approximately three years after TKA. To evaluate potential risk factors for the development of PKS, TKA alignment was measured via postoperative X-ray images. RESULTS: Improvement of the average knee flexion of 35.7° and total flexion of 107.4° was detected in PKS patients after MUA. The flexion of the control group was 112.4°; no significant between-group difference was present regarding prosthesis type, sex, age and BMI. Regarding KSS, WOMAC, and SF-12, the MUA cohort achieved statistically-relevant lower overall scores than the control group, p = 0.006, p = 0.005, p = 0.001, respectively. Significantly higher experiences of pain and a higher need for analgesics in MUA patients were reported (p = 0.001 and p < 0.001, respectively). Radiological evaluation of the prosthesis alignment did not show any differences between the two groups. CONCLUSIONS: MUA can improve mobility after PKS, whereby MUA seemed to be a functional therapy option for PKS. Compared to the control group, the MUA group showed lower functional values and an increased experience of pain. A correlation between prosthesis malalignment and MUA could not be detected radiologically. Further studies are necessary to investigate the reasons for PKS.

Short term results of dynamic splinting for hallux valgus - A prospective randomized study.

Background Hallux valgus is a common diagnosis in orthopedics. Only a few studies have analyzed the effects of conservative therapy. Therefore, the current study analyzed the effect of a dynamic hallux valgus splint. Methods Seventy patients were included in this prospective randomized trial. Patients with a hallux valgus were treated using a dynamic splint or underwent no treatment. Clinical and radiological parameters were evaluated. Results We found no significant changes in hallux valgus angle, intermetatarsal I-II angle, AOFAS score, FAOS or SF-36 score between the groups. However, a significant between-group difference was found for pain during walking and running and in the FAOS subscale for pain and pain at rest at follow-up. Conclusions Wearing a dynamic hallux valgus splint does provide some pain relief in patients with a symptomatic hallux valgus, but showed no effect on hallux valgus position. Level of evidence: 1.

Relevance of SPECT-CT in Complex Cases of Foot and Ankle Surgery: A Comparison With MRI.

BACKGROUND: Finding the right diagnoses in patients with complex foot and ankle disorders can be challenging. Single-photon emission computed tomography and computed tomography (SPECT-CT) has shown to be feasible in foot and ankle surgery. The aim of this study was to evaluate the reliability and accuracy of SPECT-CT and thereby its impact on final treatment decision compared with magnetic resonance imaging (MRI). METHODS: A retrospective study was performed on 49 patients treated at our institution. Experienced foot and ankle surgeons independently, and blinded, analyzed clinical data and radiographs together with MRI, SPECT-CT, or a combination of both. Based on the determined final treatment decision Cohen's kappa values were calculated to illustrate interrater and intrarater reliability. RESULTS: The kappa values for interrater reliability were higher for SPECT-CT at .68 and MRI + SPECT-CT at .71 compared to 0.38 for MRI alone (P < .05). The kappa values for intrarater reliability of MRI + SPECT-CT were higher at .75 compared with SPECT-CT alone at .67 (P < .05) and MRI at .35 (P < .01). CONCLUSION: We found a higher interrater and intrarater reliability for SPECT-CT compared with MRI alone for diagnosing complex foot and ankle pathologies. SPECT-CT has a high impact on final treatment decision. The main indications are bony pathologies with diagnostic uncertainty especially in closely adjacent structures as the joints of the midfoot, occult coalitio, stress fractures, verification or exclusion of nonfusion, periprosthetic disorders after total ankle replacement and osteochondral lesion in cases of combined pathologies.Levels of Evidence: Level IV: Retrospective study.

The computed tomographybased anatomy of the ossa cuneiformia.

There is a lack of basic anatomic information regarding the ossa cuneiformia. The aim of the present descriptive study was the detailed evaluation of the anatomy of the ossa cuneiformia. We analyzed 100 computer tomography scans of feet without deformities or previous trauma. The length, height and width of each cuneiforme and their articular surfaces were assessed. We itemized the data to gender differences and to foot length. The medial cuneiforme os had a length of 24.0 mm ± 2.4 (mean ± standard deviation), a width of 17.3 mm ± 2.8 and a height of 28.0 mm ± 3.4. The respective values for the intermediate cuneiforme were 18.2 mm ± 2.1, 15.8 mm ± 2.1 and 22.5 ± 2.2 and for the lateral cuneiforme 26.4 mm ± 2.7, 17.2 mm ± 2.9 and 22.8 mm ± 2.9. We found statistical relevant differences regarding gender and foot length subgroups whereas not for all parameters. The present study illustrates basic anatomic data regarding the ossa cuneiformia. This information might be helpful for implant design and placement during midfoot surgery.

Outcomes of Evans Versus Hintermann Calcaneal Lengthening Osteotomy for Flexible Flatfoot.

BACKGROUND: Evans (E) and Hintermann (H) lateral lengthening calcaneal osteotomies (LLCOTs) are commonly used to correct flexible flatfoot deformities. Both methods are well accepted and produce good clinical results. The aim of this study was to compare the postoperative outcomes of both osteotomies. METHODS: We retrospectively examined 53 patients with flatfoot deformities, who received surgery between October 2008 and March 2014. Seventeen E-LLCOT and 36 H-LLCOT procedures were performed during this time period, with a mean follow-up of 67.7 ± 20.6 and 40 ± 12.9 months, respectively. Data were collected using clinical and radiological examination, as well as clinical scores (Foot and Ankle Outcome Score [FAOS], University of California at Los Angeles [UCLA] activity score, numerical rating scale [NRS], and the Short-Form 36-item Health Survey [SF-36]) during regular follow-up. RESULTS: For both groups of patients, the FAOS score, pain-NRS, and SF-36 improved significantly following surgery ( P < .05). The talus-second metatarsal angle, talonavicular coverage, and naviculocuneiform overlap showed significant correction ( P < .05). Postoperatively, radiographic degenerative changes were detected in the calcaneocuboid (CC) and subtalar joint in both groups of patients: 41% and 18% after E-LLCOT compared with 25% and 14% after H-LLCOT, although these changes did not have any clinical relevance ( P < .05). No secondary arthrodesis was necessary. There were no significant differences in the clinical or radiological outcome parameters when compared between the 2 groups. CONCLUSION: Both surgical techniques resulted in a significant improvement of clinical outcome scores and led to good radiological correction of flatfoot deformities. It appears that the CC joint develops less degenerative changes following the H-LLCOT procedure. LEVEL OF EVIDENCE: Level III, comparative series.

The geometrical axis of the talocrural joint-Suggestions for a new measurement of the talocrural joint axis.

BACKGROUND: Despite intensive research there is no consensus about the talocrural joint axis. The aim of the present study is a new method to determinate the geometric rotational axis of the talocrural joint. METHODS: We analyzed 98 CT-scans of full cadaver Caucasian legs. We generated three-dimensional reconstruction models of the talus. A best fitting cone was orientated to the talar articular surface. The geometric rotational axis was defined to be the axis of this cone. RESULTS: The geometric rotational axis of the talocrural joint is orientated from lateral-distal to medial-proximal (85.6°±10 compared to anatomical tibial axis in torsional plane), from posterior-distal to anterior-proximal (81.43°±44.35 compared to anatomical tibial axis in sagittal plane) and from posterior-medial to anterior-lateral (169.2°±5.91 compared to intermalleolar axis in axial plane). CONCLUSIONS: The consideration of our results might be helpful for better understanding of ankle biomechanics.