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Background Asymptomatic acromioclavicular osteoarthritis (AC-OA) is a frequent finding in shoulder magnetic resonance imaging (MRI). Its natural course is unknown. Therefore, the question arises whether a resection should be performed simultaneously with shoulder surgery for another reason to prevent future pain and reoperation. The purpose of this study was to investigate the mid-term course of asymptomatic AC-OA. Methods Overall, 114 asymptomatic AC-OA diagnosed on MRI were followed for 7 years between 2011 and 2018. At baseline, MRI signal enhancement in the clavicle and acromion, OA grade, physical demand as well as the parameters (1) Constant Score Visual Analogue Scale, (2) pain on AC-joint compression, and (3) cross-body adduction test were measured. All patients were followed up after 7 years by interview, and in case of symptoms by clinical examination. The endpoint “deterioration” was reached if 2 of the 3 parameters turned worse. Results Asymptomatic AC-OA remained asymptomatic in 83% of cases, 7% turned better, 10% turned worse. Physical demand and osteoarthritis grade increased the risk of deterioration, whereas MRI signal enhancement in the clavicle or acromion had no influence on outcome. During follow-up, the frequency of pain on AC-joint compression increased from 11% to 16% (P = .24), the frequency of a positive cross-body adduction test increased from 6% to 20% (P = .017), and the mean Constant Score Visual Analogue Scale increased from 10 to 13 points (P Conclusions Asymptomatic AC-OA remained asymptomatic in 90% over 7 years. A simultaneous resection of an asymptomatic AC-OA during shoulder surgery for another reason is not indicated in every patient.

Background: Stiffness after open hallux valgus surgery affects 7% to 38% of patients. Minimally invasive surgery (MIS) is thought to decrease this rate by reducing soft tissue trauma. MIS, now in its third generation, is advertised as delivering results superior to open surgery. However, no studies have reported stiffness or range of motion (ROM). Methods: Between January 2014 and December 2015, a total of 50 patients received open scarf-Akin surgery and 48 received minimally invasive Chevron Akin (MICA) surgery. The endpoints were American Orthopaedic Foot & Ankle Society (AOFAS) score, range of motion, visual analog scale for pain, scar length, and subjective foot value. The minimal follow-up time was 2 years. Results: Moderate stiffness occurred in 3 cases in both groups. In MICA, extension increased by 10 degrees while it remained unchanged in scarf. Both groups showed similar improvements in AOFAS score, pain, and subjective foot value. Radiographic evidence of correction was comparable, except for an increased shortening of the first metatarsal by 3 mm in MICA. The scars were smaller in MICA (1.2 cm) than in scarf (5 cm). Wound problems included delayed healing in 10% in scarf and wound infections in 4% in MICA. The rate of recurrence and other complications were comparable, except for reoperations, which were higher in MICA (27% mainly for protruding screws) than in scarf (8% mainly for stiffness). In MICA, 14% were intraoperatively converted to open surgery. Conclusion: MICA showed no advantages over scarf other than a shorter scar. The observed gain in extension could be related to the increased shortening of the first metatarsal because of the size of the burr. Level of Evidence: Level II, prospective cohort (nonrandomized, comparative) study.

Background: Gait analysis after total ankle replacement and ankle arthrodesis is usually measured barefoot. However, this does not reflect reality. The purpose of this study was to compare patients barefoot and with footwear. Methods: We compared 126 patients (total ankle replacement 28, ankle arthrodesis 57, and tibiotalocalcaneal arthrodesis 41) with 35 healthy controls in three conditions (barefoot, standardized running, and rocker bottom shoes). Minimum follow-up was 2 years. We used dynamic pedobarography and a light gate. Main outcome measures: relative midfoot index, forefoot maximal force, walking speed. Findings: The relative midfoot index decreased in all groups from barefoot to running shoes and again to rocker bottom shoes (p < 0.001). The forefoot maximal force increased wearing shoes (p < 0.001), but there was no difference between running and rocker bottom shoes. Walking speed increased by 0.06 m/s with footwear (p < 0.001). Total ankle replacement and ankle arthrodesis were equal in running shoes but both deviated from healthy controls (total ankle replacement/ankle arthrodesis smaller RMI p = 0.07/0.017; increased forefoot maximal force p = 0.757/0.862; slower walking speed p < 0.001). In rocker bottom shoes, this ranking remained the same except the relative midfoot index merged to similar values. Tibiotalocalcaneal arthrodesis were inferior in both shoes. Interpretation: Runners are beneficial and the benefit is greater for fusions and replacements. Rocker bottom shoes have little added benefit. Total ankle replacement and ankle arthrodesis were equal but inferior to healthy controls. Tibiotalocalcaneal arthrodesis has an inferior outcome.

Background Pedobarography offers dynamic information about the foot, but the interpretation of its large data is challenging. In a prior study it was shown that attention can be restricted to pedobarographic midfoot load data. We aim to verify this observation in ankle osteoarthritic and contralateral feet. Methods We assessed both feet of 120 patients with end-stage ankle osteoarthritis (OA) and 35 healthy volunteers with AOFAS-score and dynamic pedobarography in barefoot condition. We introduce a new parameter, the Relative Midfoot Index (RMI), representing the depth of the midfoot weighted by the maximal force (MF) in the hindfoot and forefoot. Main outcome measures were the RMI, MF and contact times in the hindfoot, midfoot and forefoot. Ankle OA, contralateral and healthy feet were compared with ANOVA. Results The RMI was significantly smaller in OA feet (0.65 ± 0.19) and contralateral feet (0.69 ± 0.15) than in healthy feet (0.84 ± 0.08, p

Zusammenfassung: Die Arthrose des oberen Sprunggelenks (OSG) ist häufig mit einer Fehlstellung verbunden, dabei ist die Valgusarthrose seltener als die Varusarthrose. Die Ursachen für eine Valgusarthrose sind eine mediale Bandinstabilität, ein Pes planovalgus und posttraumatische Fehlstellungen z.B. nach Fibulafraktur oder Stauchung des lateralen Tibiaplateaus. Damit eine OSG-Prothese kurz- wie auch langfristig korrekt und schmerzfrei funktionieren kann, muss die Biomechanik entsprechend den Prinzipien der mechanischen Achse, deren Wichtigkeit in der Orthopädie allgemein akzeptiert ist, wiederhergestellt werden. Richtlinien sind dabei (1) ein anteriorer tibiotalarer Winkel von etwa 90° und (2) eine neutrale Rückfußstellung. Diese wird vorzugsweise mit der Rückfußaufnahme nach Saltzman gemessen. Dabei ist zu beachten, dass der normale Rückfuß in einer Neutralstellung bis 1-2° Varusposition und nicht wie bisher angenommen in einer Valgusstellung ist. Je nach Ausmaß und Lokalisation der Valgusdeformität werden in unterschiedlicher Reihenfolge (1) die OSG-Prothese implantiert, (2) supra- und (3) inframalleoläre Korrekturosteotomien/-Arthrodesen, (4) eine mediale Bandplastik, (5) eine Fibulaosteotomie (6) mit eventueller Rekonstruktion der Syndesmose durchgeführt

Zusammenfassung: Die Beurteilung des Ausmaßes von Bandinstabilitäten des oberen Sprunggelenks (OSG) mittels klinischer und radiologischer Diagnostik fällt oft schwer. Umfang und Häufigkeit insbesondere der medialen Instabilität werden dabei häufig unterschätzt. Werden bei einer operativen Rekonstruktion nicht alle betroffenen Bänder eingeschlossen, können Instabilität und Beschwerden persistieren. In einer konsekutiven Serie von 281 chronisch instabilen Sprunggelenken (188Frauen, 93Männer, Alter 35,8 [15-61] Jahre) fand sich in 140Fällen (50%) eine Verletzung des Lig.deltoideum, und diese war in 103Fällen (37%) mit einer Verletzung der lateralen Bänder kombiniert. Eine isolierte laterale Instabilität lag in 121Fällen (43%) und eine isolierte mediale Instabilität in 38 Fällen (14%) vor. Die präoperative arthroskopische Untersuchung des Sprunggelenks hat sich als hilfreich erwiesen, den Umfang der ligamentären Insuffizienz sowie begleitende Schäden zu erkennen. Diese Informationen hätten meist auch mit aufwändigen bilddiagnostischen Maßnahmen nicht in diesem Ausmaß gewonnen werden können. Die Erkenntnisse aus der funktionellen Prüfung der medialen und lateralen Bandstrukturen erlauben dem Chirurgen, die notwendige operative Rekonstruktion optimal dem Verletzungsmuster anzupassen. Dies ist deshalb so wichtig, weil gezeigt werden konnte, dass die Sprunggelenkinstabilität nicht einer einzigen Entität entspricht, sondern eine hohe Variabilität aufweist. Obschon nicht in einer randomisierten Studie nachgewiesen, sind wir doch der Meinung, dass die präoperative Arthroskopie die Effizienz der operativen Behandlung der symptomatischen, konservativ erfolglos behandelten Instabilität des Sprunggelenks verbessert. Die arthroskopische Untersuchung wird deshalb dem Patienten Nutzen bringen, aber auch volkswirtschaftlich sinnvoll sein

Zusammenfassung: Achillessehnenrupturen (ASR) sind mit zunehmender Tendenz die häufigsten Sehnenrupturen der unteren Extremität, wohingegen weniger als 100Fälle von Tibialis-anterior-Sehnenrupturen (TASR) in der Literatur beschrieben wurden. Beiden Sehnen gemeinsam sind die in der Regel degenerativ verursachten Rupturen in einem dafür anfälligen Sehnenabschnitt, wohingegen die traumatischen Durchtrennungen selten und ohne Ortsbeziehung vorkommen. Triceps surae und Tibialis anterior sind hauptverantwortlich für die sagittale Bewegung im oberen Sprunggelenk und führen bei Ruptur zu einem unverwechselbaren funktionellen Defizit. Trotzdem werden ASR in bis zu 25% und der TASR noch häufiger verspätet diagnostiziert. Die frühzeitige primäre Naht hat die besten funktionellen Ergebnisse. Durch zunehmende Retraktion und Muskelatrophie kann eine verspätete chirurgische Sehnenrekonstruktion nur ein weniger gutes funktionelles Resultat erreichen. Jedoch braucht nicht jeder Patient eine volle Belastbarkeit, Kraft und Ausdauer dieser Muskeln und so dürfen konservative Maßnahmen nicht vergessen werden. Inaktive Patienten mit eingeschränktem Allgemeinzustand und geringen Beschwerden sollten aufgeklärt werden, dass die chirurgische Therapie der TASR eine hohe Rerupturrate aufweist und der ASR selten transplantationspflichtige Wundheilungsstörungen verursachen kann

Background: Locking plates are widely used in fracture fixation, mainly for meta-diaphyseal fractures, comminuted fractures, fractures with a critical-size bone defect, periprosthetic fractures, osteotomies, and fractures in osteoporotic bone. The aim of this animal study was to evaluate the effect on bone-healing of dynamization of locking plate constructs by means of new 5.0-mm dynamic locking screws (in the DLS group), which allow near-cortex micromotion, compared with a more rigid construct utilizing standard bicortical locking-head screws (in the LS group). Use of dynamic locking screws allows modulation of the stiffness of existing locking compression plate systems via parallel interfragmentary micromotion. Methods: A standardized diaphyseal tibial osteotomy (90°, 3-mm fracture gap) was performed and stabilized with a six-hole large-fragment locking compression plate in twelve female sheep (six in each group). Radiographs were made postoperatively and then weekly from week three until sacrifice at nine weeks. Macroscopic, biomechanical, histologic, and radiographic assessments and microcomputed tomography were performed. Results: The callus in the tested specimens in the DLS group had better biomechanical stability, with a significantly greater maximum failure moment (mean and standard deviation [SD] as a percentage of intact, 55.15 ± 20.65 compared with 26.80 ± 14.96 in the LS group; p = 0.021). The DLS group also had greater periosteal callus volume at the near cortex (mean volume and SD as a percentage of the tibial shaft volume, 36.21% ± 10.08% compared with 18.98% ± 8.61% in the LS group; p = 0.026) and in the intercortical region (mean volume and SD as a percentage of the bone volume of the tibial shaft, 3.56% ± 0.52% compared with 2.64% ± 0.98% in the LS group; p = 0.045), as shown by microcomputed tomography. The DLS group also had significantly greater torsional stiffness (mean and SD as a percentage of intact, 84.88 ± 13.51 compared with 58.89 ± 20.61 in the LS group; p = 0.027). Conclusions: Controlled micromotion and nearly homogeneous interfragmentary strain at the fracture site, together with the stable bicortical fixation achieved by the new dynamic locking screw, led to more uniform callus formation, significantly more callus formation at the near cortex, and biomechanically more competent bone-healing compared with use of rigid locking plate constructs with locking-head screws.

The purpose of this study was to evaluate survival and clinical outcome of the Scandinavian total ankle replacement (STAR) prosthesis after a minimum of ten years up to a maximum of 19 years. Fifty STAR prostheses in 46 patients with end stage ankle osteoarthritis operated between 1996 and 2006 by the same surgeon (MH) were included. Minimal follow-up was ten years (median 14.6 years, 95% confidence interval [CI] 12.9-16.4). Clinical (Kofoed score) and radiological assessments were taken before the operation and at one, ten (+2), and 16 (±3) years after implantation. The primary endpoint was defined as exchange of the whole prosthesis or conversion to arthrodesis (def. 1), exchange of at least one metallic component (def. 2), or exchange of any component including the inlay (due to breakage or wear) (def. 3). Survival was estimated according to Kaplan-Meier. Further reoperations related to STAR were also recorded. The ten year survival rate was (def. 1) 94% (CI 82-98%), (def. 2) 90% (CI, 77-96%), and (def. 3) 78% (CI 64-87%). The 19-year survival rate was (def. 1) 91% (CI 78-97%), (def. 2) 75% (CI 53-88%), and (def. 3) 55% (CI 34-71%). Considering any re-operations related to STAR, 52% (26/50) of prostheses were affected by re-operations. Mean pre-operative Kofoed score was 49, which improved to 84 after one year (n = 50), to 90 after ten years (n = 46), and to 89 after 16 years (n = 28). The survival rate for def. 1 and 2 was high. However, re-operations occurred in 52% of all STAR prosthesis. Retrospective cohort study, evidence Level 4.

Background:Depending on the direction of the subtalar joint, a foot deformity generally tends towards pronation (pes planovalgus) or supination (pes cavovarus). However, the combination of hindfoot varus and flat midfoot/forefoot (pes planovarus) is an exception to this rule. Pes planovarus has so far only been referred to in connection with Müller-Weiss disease and congenital disease. We diagnosed pes planovarus in otherwise healthy patients without these diseases.Methods:Forty patients with 54 symptomatic feet who were treated between August 2012 and July 2016 were included (mean age, 44.1 ± 15.7 years; 15 male/25 female). They were selected from 1064 consecutive cases (3.8%). Inclusion criteria were hindfoot varus and flat midfoot/forefoot. Their symptoms, radiographs, and therapies within the first 3 months were retrospectively analyzed. The position in the hindfoot alignment view (HAV), talometatarsal-1 angle lateral (TMT1lat) and dorsoplantar (TMT1dp), talocalcaneal angle lateral (TCAlat) and dorsoplantar (TCAdp), and calcaneal pitch angle (CPA) were measured on a DICOM/PACS system.Results:The mean radiological results (standard values from the literature in brackets) were as follows: the hindfoot was significantly in varus in the HAV (−6.9 ± 3.6 mm [−1.6 ± 7.2 mm]; P < .001), the TMT1lat was significantly flatter (−6.7 ± 5.8 degrees [8.4 ± 5.9 degrees]; P < .001), the TMT1dp was significantly less in abduction (1.5 ± 7.9 degrees [7.7 ± 8.2 degrees]; P = .005), the TCAdp showed no difference (25.9 ± 7.9 degrees [24.1 ± 5.7 degrees]; P = .118), the TCAlat was significantly larger (47.5 ± 6.1 degrees [43.4 ± 7.1 degrees]; P < .001), and the CPA was significantly flatter (17.6 ± 3.9 degrees [24.5 ± 3.0 degrees]; P < .001). The most frequent symptoms were stress-induced foot pain (n = 33), hallux valgus (n = 20), chronic ankle instability (n = 17), metatarsalgia (n = 15), chronic midfoot pain (n = 13), heel pain (n = 12), and lesser toe deformities (n = 8). Thirty-one feet were treated conservatively and 23 operatively.Conclusion:This study showed the existence of pes planovarus without Müller-Weiss disease or congenital disease. This unusual foot form leads to difficulties if standard treatment strategies are applied, which raises the issue of the correct treatment for such patients.Level of Evidence:Level IV, retrospective case series.

The resection of os trigonum or posterior talar process as treatment for posterior ankle impingement is an established operation. However, the authors encountered several painful stress reactions in the posterior subtalar joint during follow-up resulting in persisting incapacity to do sports. From March 2011 to July 2015, 29 patients with 30 feet were operated (22 endoscopic, 8 open resections). Average follow-up time was 43 ± 13 months. Complications were grouped into “none”, “temporary disadvantage” and “permanent damage”. The following radiographic parameters were measured: (1) length of posterior talar process or os trigonum, (2) length of the uncovered calcaneal joint surface after resection, (3) amount of resection. The rate of permanent damage was 13.3% (4 of 30 feet), and all four of these patients developed a painful stress reaction in the posterior subtalar joint. One temporary disadvantage (persistent pain for three months) was found. All patients with major complications showed retrospectively what we call the “risk configuration” —the radius of the talus ending within the subtalar joint. The length of the uncovered calcaneal joint surface was therefore significantly larger (6.4 mm ± 3.33) in feet with permanent damage than in feet without (1.06 mm ± 2.15, P

The Saltzman-el-Khoury hindfoot alignment view (HAV) is considered the gold standard for assessing the axis from hindfoot to tibia. However, it is unclear whether radiographic alignment influences dynamic load distribution during gait.We evaluated varus-valgus alignment by the HAV and its influence on dynamic load distribution in ankle and tibiotalocalcaneal (TTC) arthrodesis.We clinically assessed 98 patients (ankle, 56; TTC, 42) with SF-36 and American Orthopaedic Foot and Ankle Society (AOFAS) scores, visual hindfoot alignment, HAV angle, and dynamic pedobarography using a five-step method. For comparison, 70 normal feet were evaluated. Minimum followup was 2 years (average, 4.11 years; range, 2-6 years).The mean HAV angle was -0.8° ± 7.8° for ankle and -1.2° ± 6.9° for TTC arthrodesis. The HAV angle correlated with pedobarographic load distribution (r = 0.35-0.53). Radiographic alignment did not influence SF-36 or AOFAS scores; however, load distribution correlated to qualities of these scores. Visual alignment only predicted the corresponding HAV angle in 48%. To reproduce the dynamic load of healthy subjects, HAV angles of 5° to 10° valgus were needed.Visual positioning is inadequate to determine intraoperative positioning and resulted in a varus position with a relatively large SD. The HAV should be used to assess the hindfoot alignment correctly. HAV angles of 5° to 10° valgus are needed to reproduce a physiologic gait pattern.

Background: Alignment is instrumental for success and long-term survival of Total Ankle Replacement (TAR). At this point in TAR, only coronal alignment in the region of the tibiotalar joint or above has been assessed because inframalleolar deformity is difficult to visualize radiographically. The Hindfoot Alignment View (HAV) allows visualization of the hindfoot position relative to the tibia. The purpose of this study was to evaluate the clinical relevance of this view in assessing patients with TAR. Materials and Methods: Twenty-eight consecutive patients with a Hintegra-TAR with an average followup of 4.1 ± 1.5 years were followed with (1) AOFAS and SF-36 scores, (2) visual judgment of the hindfoot position, (3) HAV and AP/lateral radiographs, (4) dynamic pedobarography (Novel emed m/E, Munich, Germany). Results: The HAV position correlated well with different load parameters on heel strike ( r = 0.44 to 0.62) but not with the varus-valgus load pattern of the rest of the foot. Visual judgment and TAR joint line did not correlate to radiographic hindfoot alignment or to pedobarographic load distribution. The hindfoot alignment measured by the HAV correlated significantly to the Physical Function and Role Physical of SF-36. No correlation was found to other SF36-qualities or the AOFAS-score. Conclusion: Inframalleolar alignment, as assessed by the HAV, influenced the dynamic pedobarographic load pattern and clinical outcome. Visual judgment and TAR joint line were not accurate enough to estimate the hindfoot alignment or dynamic load pattern. We believe adjusting the hindfoot correctly with HAV might improve long-term outcome and survival of TAR. Level of Evidence: IV, Retrospective Case Series

Summary Treatment of clavicular midshaft fractures with the Titanium Elastic Nail (TEN) combined with free range of motion (ROM) postoperatively revealed a high complication rate of 78% without endcap and 60% with endcap in our experience. This study examined how to reduce this high complication rate. From 4/04 to 12/09 63 patients were treated percutaneously using TEN without endcap (n=19, group A) and with endcap (n=44, group B+C). In group B (n=15) the TEN was advanced with the oscillating drill and free ROM was allowed postoperatively. In group C (n=29) the TEN was inserted carefully with a T-handle and ROM was limited to 90°. Mean follow-up was 23 months (12-52). The complication rate decreased from 78% to 60% from group A to group B. The complications were then significantly reduced to 10% in group C. There were no more medial perforations with the Endcap. Limitation of ROM during 6 weeks postoperatively as well as careful advancement of the TEN reduced the complication rate significantly to an acceptable level. Intramedullary stabilisation of claviclular midshaft fractures with TEN is a minimally invasive technique with results comparable to the current gold standard of plate osteosynthesis.

Background Intramedullary nailing of clavicular midshaft fractures using the titanium elastic nail has been described as a technically easy, minimally invasive operation with few complications and an early return to competitive sports. Hypothesis The results reported thus far have been positive. The titanium elastic nail is associated with multiple intraoperative and postoperative problems. Study Design Case series; Level of evidence, 4. Methods From April 2004 to March 2007, 34 patients at our institution were treated with intramedullary nailing. A standard titanium elastic nail was used in 19 cases and a titanium elastic nail with an end cap in 15 cases. The titanium elastic nail was inserted and advanced under fluoroscopic control. A short incision at the fracture site was made for open reduction if needed. Postoperatively, free range of motion was allowed. Results In 62% of patients, open reduction was necessary independent of fracture type, flattening of the titanium elastic nail, or transverse fragments. Operating time was 44 minutes (range, 10—105 minutes) and fluoroscopy time 9 minutes (range, 2—25 minutes). In 70% of patients, problems or complications occurred (7 medial perforations, 7 lateral penetrations, 1 titanium elastic nail breakage, 1 titanium elastic nail dislocation, 7 hardware irritations). The reoperation rate was 36%. Medial migration and pain were significantly reduced by using an end cap. Conclusion Intramedullary nailing of clavicular midshaft fractures using the titanium elastic nail is a technically demanding operation with various complications in the postoperative phase. This study might explain why the implant has not yet achieved widespread application, despite the fact that other authors have reported good results. Amending the operative technique and postoperative treatment might improve the outcome in the future.

The osseous ankle configuration (tibiotalar sector, talar radius and height) has been discovered as intrinsic risk factor for chronic ankle instability (CAI). These measurements were done on lateral radiographs only. In this study, the osseous characteristics in the frontal plane and further lateral values were measured.Level III case-control study.Radiological measurement of frontal and lateral radiographs by one independent, blinded radiologist using a digital DICOM/PACS system.A group of 52 patients with CAI was compared with an age- and sex-matched control group of 52 healthy subjects.In the frontal plane, the depth of the talar curvature (frontal curvature (froCu)) and the lateral and medial malleolar lengths were measured. In the lateral plane, the position of the centre of rotation to the tibial axis (talar centre of rotation to the anatomical axis of the tibia (TibCOR)) and the tibial lateral surface angle (TLS) were also measured.The froCu was deeper in patients with CAI (1.8 (0.5) mm) than in healthy subjects (1.0 (0.5) mm, p0.05). The TibCOR was more anterior in patients with CAI (2.5 (1.9) mm) than in healthy subjects (1.6 (2.2) mm, p0.05). The distance from the fibular tip to the centre of rotation was smaller in patients with CAI (3.5 (3.4) mm) than in healthy subjects (6.5 (3.3) mm, p0.05). The TLS and the length of the lateral and medial ankle were not significantly different.This study supports that the osseous joint configuration is an intrinsic risk factor for CAI. It could be shown that CAI is characterised by a deeper frontal curvature of the talus and a more anterior position of the talus to the tibia.

Zusammenfassung: Die chronische Sprunggelenkinstabilität ist eine typische Pathologie im Sport und entwickelt sich bei 20 bis 40% der Sportler nach erlittener akuter Sprunggelenkdistorsion. Man unterscheidet zwischen einer lateralen und medialen Sprunggelenkinstabilität, wobei die Kombination beider als Rotationsinstabilität des oberen Sprunggelenks bezeichnet wird. Des Weiteren kann pathophysiologisch eine mechanische oder funktionelle Sprunggelenkinstabilität unterschieden werden, die sich durch eine strukturelle Bandläsion bzw. durch eine Schwächung der neuromuskulären Kontrolle manifestiert. Durch die erschwerte Diagnose und eine komplexe Therapie, die oft eine operative Rekonstruktion bedingt, stellt die chronische Sprunggelenkinstabilität für den behandelnden Arzt eine vielschichtige Entität dar. Die vorliegende Übersichtsarbeit erörtert Pathomechanismen, Möglichkeiten der Diagnostik, Indikationen zur konservativen und operativen Therapie sowie potenzielle Langzeitschäden wie die posttraumatisch-ligamentäre Sprunggelenksarthrose

Chronic ankle instability represents a typical sports injury which can mostly be seen in basketball, soccer, orienteering and other high risk sports. 20 to 40 % of the acute ankle sprains develop into chronic ankle instability. From a sports orthopaedic point of view, chronic ankle instability can be subdivided into a lateral, medial or a combination of both so called rotational ankle instability. From a pathophysiological point of view, chronic ankle instability can be either mechanical with a structural ligament lesion or functional with loss of the neuromuscular control. For the sports physician, the chronic ankle instability is a difficult entity as the diagnosis is usually complex and the therapy usually surgical. This review on chronic ankle instability addresses pathomechanism, diagnostics, indications for conservative and surgical treatments, and possible long-term sequelae, as ligamentous osteoarthritis.

The combination of spontaneous anterior tibial tendon rupture and posterior tibial tendon dysfunction has rarely been reported in the literature. This is a case report of a 78-year-old patient presenting with a history of longstanding, progressive flatfoot deformity, clinically grade III posterior tibial tendon dysfunction, and dropfoot gait. Radiographic films revealed severe flatfoot, and the clinical examination was consistent with a complete rupture of the anterior tibial tendon and severe posterior tibial tendon degeneration as well as rupture of the spring and deltoid ligaments. Treatment by triple arthrodesis and repair of the anterior tibial tendon affected pain relief and clinical as well as radiographic correction at the 4-month postoperative assessment.

Zusammenfassung Bandlasionen des oberen Sprunggelenkes sind die haufigste Verletzung im Sport. Das Risiko einer Distorsion des oberen Sprunggelenkes (OSG) zu erleiden, hangt von intrinsischen (Ruckfusstellung, Laxitat, Kraft, neuromuskulare Reaktion u.a.) sowie extrinsischen Faktoren (Schuhwerk, Sportart, Aufwarmen u.a.) ab. Entsprechende Masnahmen zur primaren Pravention sind das Aufwarmen vor dem Sport, Training der Muskulatur und neuromuskularen Reaktion sowie korrektes Schuhwerk und ggf. ausere stabilisierende Masnahmen. Die korrekte Behandlung des Erstereignisses einer OSG-Distorsion konservativ und operativ sowie die Behandlung der Risikofaktoren und klinische Nachkontrollen stellen die wichtigsten Bausteine zur sekundaren Pravention der chronischen Instabilitat dar. Die Behandlung der chronischen Instabilitat stellt einen wichtigen Punkt in der tertiaren Pravention einer posttraumatisch-ligamentaren OSG-Arthrose dar.

Die chronische Instabilitat des oberen Sprunggelenkes (OSG) ist eine haufige Entitat im Sport. Das Risiko, eine Distorsion des OSG zu erleiden, hangt von intrinsischen (Ruckfus-Stellung, Laxitat, Kraft, neuromuskulare Reaktion u. a.) sowie extrinsischen Faktoren (Schuhwerk, Sportart, Aufwarmen u. a.) ab. Die chronische OSG-Instabilitat wird in eine laterale, mediale und kombinierte Rotationsinstabilitat unterteilt. Zur korrekten Therapie gehort auch die Behandlung der Begleitverletzungen, damit eine rasche Ruckkehr zum Sport wieder moglich ist. Grundsatzlich gilt primar eine konservative Therapie, da ein mechanisches Defizit mit Training der neuromuskularen Kontrolle ausgeglichen werden kann. Sollte dennoch eine symptomatische chronische OSG-Instabilitat vorliegen, ist eine anatomische Bandrekonstruktion indiziert. Dies ist entscheidend, um Verletzungspausen kurz zu halten und die Progredienz von der chronischen Instabilitat zur OSG-Arthrose zu verhindern.

Stressfrakturen von Unterschenkel und Fus sind eine haufige Verletzung des Sportlers, insbesondere des Langstreckenlaufers. Die Stressfraktur entsteht dabei oft aufgrund einer Progredienz von chronischen Uberlastungsschaden (z. B. shin splint). Verschiedenste Ursachen konnen als Ausloser oder zusatzliche Risikofaktoren dazu fuhren, dass das ossare Remodellierungspotential nicht ausreicht, den applizierten Belastungen standzuhalten. Fur den Sportler stellen sich drei wichtige Punkte in den Vordergrund: rasches Erzwingen der Diagnose, funktionelle Nachbehandlung mit aktiver (Alternativ)- Belastung, praventive Masnahmen zur Rezidivprophylaxe.

Some major complications of internal fixation with plates, such as infections and disturbance of healing, have been shown to be related to necrosis of bone and to the soft tissues immediately deep to the plate. This is attributable to plate contact. To deal with this phenomenon, an internal fixator, the Point Contact Fixator, was developed according to a new concept. The Point Contact Fixator resembles a plate but functions like a fixator, that is, the fracture is stabilized using a splint fixed to the bone by monocortical, angularly locked screws that are designed not to exert pressure between the splint and the bone, thereby minimizing implant-to-bone contact. Vascular damage to the osseous blood supply consequently is avoided. The new internal fixator is the first of a new family of implants in addition to nails, plates, and external fixators. To study the potential of the Point Contact Fixator in a prospective study, 79 forearm fractures in 55 patients were treated in a consecutive series by one surgeon using the same technique throughout. Followup to union is reported for 100% of the patients. Handling the fixator was simple; healing was uneventful; and the rate of complication was low.

Chronic ankle instability (CAI) is a frequent sport orthopaedic entity. Although many risk factors have been studied extensively, little is known how it is influenced by the osseous joint configuration. Based on lateral X-rays, the radius of the talar surface and the tibial coverage of the talus (sector alpha) were measured on a DICOM/PACS system in 52 patients with CAI and an age- and sex-matched control group. The talar radius was found to be larger in patients with CAI (21.2 +/- 2.4 mm) than in the control group (17.7 +/- 1.9 mm; P < 0.0001). The tibio-talar sector was smaller in patients with CAI (80 degrees +/- 5.1 degrees ) than in the control group (88.4 degrees +/- 7.2 degrees ; P < 0.0001). The aim of this study is to analyse the biomechanical influence of the clinical data on stability of the ankle joint. A two-dimensional model of the tibio-talar joint in the sagittal plane was developed. The joint configuration was described by the tibio-talar sector (alpha) and the radius (r) of the talus. The force (F = F (BW) tan alpha/2) and energy (E = F (BW) r [1 - cos alpha/2]) to dislocate the talus out of the tibial plafond were deduced. Ankle stability is a function of the tibio-talar sector: the force necessary to dislocate the joint is decreasing with a smaller sector. The clinical data show that the force needed to dislocate the ankle of CAI patients was 14% weaker than the one needed in the case of healthy subjects (P < 0.0001). The energy to dislocate the ankle depends both on the sector and the radius. The clinical data do not show a significant difference between the energy needed to dislocate the joint of CAI patients and the one of healthy subjects. This is because there is a correlation of a small sector and a large radius for CAI ankles. CAI is associated with an unstable osseous joint configuration, which is characterized by a larger radius of the talus and a smaller tibio-talar sector. The findings of the biomechanical model explain the clinical observations and demonstrate how stability of the ankle joint is influenced by the osseous configuration. Surgical ankle ligament stabilization might be more recommended in patients with an unstable osseous configuration as such patients have a disposition for recurrent sprains. Removing anterior osteophytes for anterior impingement should be done carefully in CAI patients because this would decrease the tibial coverage of the talus and thus dispose the talus to dislocate anteriorly. People who have an unstable ankle configuration and who nevertheless engage in activities with high risk of ankle sprains could be asked to wear ankle protecting sports equipment.

OBJECTIVE To measure the differences in intramedullary (IM) pressure for commercial reamer systems. DESIGN IM pressure values for the following systems were measured: AO, Biomet, Howmedica grey reamer, Richards, and Zimmer. To investigate the influence of shaft diameter, the AO reamer head was additionally connected to a small shaft (A6/A7). The pressures were measured in plexiglass tubes filled with a mixture of petroleum jelly and paraffin oil with flow properties at 20 degrees C equivalent to those of bovine medullary fat at 36 degrees C. The reaming assemblies were inserted into the tubes using a materials testing machine at a constant speed. In addition, pressure measurements were made using five pairs of human femora to compare Biomet reamers with the AO reamer with thin, flexible drives (A6/A7). RESULTS The following pressure distributions were obtained (millimeters of mercury; mean value +/- standard deviation): 9.5-millimeter reamer: low for Biomet (272+/-39); moderate for Richards (810+/-101); and high for Howmedica (990+/-132), AO conventional (1,000+/-97), and Zimmer (1,140+/-183); 13.0-millimeter reamer: low for Biomet (132+/-21), Howmedica (204+/-45), and Zimmer (226+/-33); moderate for AO conventional (474+/-42); and very high for Richards (1,734+/-127). The second worst system (AO conventional: 1,000+/-97) became the second best system by simple reduction of the shaft diameter (A6/A7: 378+/-33). CONCLUSION A comparison of shaft diameters and pressure increase clearly showed that the system with the thinnest shaft produced the lowest pressure values and vice versa.

Conservation of bone perfusion, protection of the soft tissue envelope and reduction of systemic stress by strengthening the host defence mechanism are general and essential aspects of a biological osteosynthesis. The minimal invasive operating techniques with the use of technical aids and tricks form the necessary presupposition for successful bone healing with a low complication rate. For an epiperiosteal, percutaneous plate osteosynthesis, the technique using a sliding tip and a manipulation handle is demonstrated.

OBJECTIVE: To measure and compare the mechanical properties in bending of the four-ring, and three-ring/one-tube hybrid external fixation frames. DESIGN. IN VITRO: measurements of the mechanical behaviour of ring and ring-tubular external fixation frames. In the latter, one ring of the full circular frame was replaced by one tube and Schanz screws. BACKGROUND: The mechanical properties of the classical Ilizarov four-ring external fixation frames has been compared to those of other external fixation frames by various authors. However, in clinical practice the hybrid fixation frame is being used with increasing frequency. Therefore the mechanical properties of the latter are of immediate interest and clinical value. METHODS: On explanted sheep tibiae with single and double osteotomies, frame stiffness in the four-point bending mode was measured at different K-wire tensions, comparing the values obtained from four-ring frames, to those of three-ring-tubular hybrid frames. These measurements were made under conditions of (a) bone distraction (BD), and (b) segment transport (ST), both at the initial and final stages of this procedure. RESULTS: In circular frames, frame stiffness in bending for increasing K-wire tension showed a Gaussian distribution both in distraction and post-ST with an optimum at 1000 N. In ring tubular hybrid frames, however, frame stiffness showed a more linear relationship to K-wire tension. CONCLUSIONS: In the four-ring Ilizarov external fixation frame, the exchange of one ring with one tube and one Schanz screw both reduced frame stiffness in bending and converted to linear its relationship to K-wire tension. RELEVANCE: Under clinical conditions, the use of a similar ring tubular hybrid external fixator allows the adjustment of frame stiffness in a simple and practical way. This is not the case with the original ring fixation frame.

Background: In a previous study, intraoperative positioning of the hindfoot by visual means resulted in the wrong varus/valgus position by 8 degrees and a relatively large standard deviation of 8 degrees. Thus, new intraoperative means are needed to improve the precision of hindfoot surgery. We therefore sought a hindfoot alignment guide that would be as simple as the alignment guides used in total knee arthroplasty. Methods: A novel hindfoot alignment guide (HA guide) has been developed that projects the mechanical axis from the tibia down to the heel. The HA guide enables the positioning of the hindfoot in the desired varus/valgus position and in plantigrade position in the lateral plane. The HA guide was used intraoperatively from May through November 2011 in 11 complex patients with simultaneous correction of the supramalleolar, tibiotalar, and inframalleolar alignment. Pre- and postoperative Saltzman views were taken and the position was measured. Results: The HA guide significantly improved the intraoperative positioning compared with visual means: The accuracy with the HA guide was 4.5 ± 5.1 degrees (mean ± standard deviation) and without the HA guide 9.4 ± 5.5 degrees ( P < .05). In 7 of 11 patients, the preoperative plan was changed because of the HA guide (2 avoided osteotomies, 5 additional osteotomies). Conclusions: The HA guide helped to position the hindfoot intraoperatively with greater precision than visual means. The HA guide was especially useful for multilevel corrections in which the need for and the amount of a simultaneous osteotomy had to be evaluated intraoperatively. Level of Evidence: Level IV, case series.

Summary:Even though the problems of intramedullary pressure increase and its effects on pulmonary function have not yet been resolved, intramedullary nailing after reaming remains a relevant treatment procedure, especially for pseudarthrosis of the tibial and femoral shaft, because good results have

Background:Long-standing rotator cuff tendon tearing is associated with retraction, loss of work capacity, irreversible fatty infiltration, and atrophy of the rotator cuff muscles. Although continuous musculotendinous relengthening can experimentally restore muscular architecture, restoration of atrophy and fatty infiltration is hitherto impossible.Hypothesis:Continuous relengthening with pharmacological stimulation of muscle growth using an anabolic steroid or insulin-like growth factor (IGF) can reverse atrophy and fatty infiltration as well as improve the work capacity of chronically retracted rotator cuff muscles in sheep.Study Design:Controlled laboratory study.Methods:Sixteen weeks after tenotomy of the infraspinatus (ISP) tendon, atrophy and fatty infiltration had developed in the retracted ISP muscle. The musculotendinous unit was continuously relengthened in 14 sheep during 6 weeks: Four sheep were treated without pharmacological stimulation, 4 with intramuscular administration of an anabolic steroid, and 6 with IGF before final repair and rehabilitation (12 weeks). Changes were documented by intraoperative measurements of muscle work capacity, histology, and computed tomography/magnetic resonance imaging.Results:Musculotendinous relengthening by continuous traction resulted in gains of length ranging from 0.7 cm in the IGF group to 1.3 cm in the control group. Fatty infiltration progressed in all groups, and the muscle’s cross-sectional area ranged from 71% to 74% of the contralateral side at sacrifice and did not show any differences between groups in weight, volume, histological composition, or work capability of the muscle. The contralateral muscles in the anabolic steroid group, however, showed significantly higher (mean ± standard deviation) muscle work capacity of 10 ± 0.9 N·m than the contralateral muscles of the control group (6.8 ± 2.4 N·m) ( P < .05). This was accompanied by an increased mean muscle fiber area as well as by an unusual gain in the animals’ weight after injection of the anabolic steroid.Conclusion:Subcutaneous continuous relengthening of a chronically retracted musculotendinous unit is feasible and advances the retracted musculotendinous junction toward its original position. This does not change the muscle work capacity. Whereas anabolic steroids have been shown to be effective in preventing classic degenerative muscle changes after tendon tears, neither an anabolic steroid nor IGF contributes to regeneration of the muscle once degenerative changes are established.Clinical Relevance:The findings demonstrate that muscle cells lose reactiveness to an anabolic steroid and IGF once retraction has led to fatty infiltration and atrophy of the muscle. Retraction of the muscle after tendon tears must be avoided by early repair, particularly in an athlete, as no regeneration can be achieved by mechanical or pharmacological means at this time.

article i nfo Keywords: Ankle Tibiotalocalcaneal Arthrodesis Pedobarography Outcome Midfoot load Background: A large number of parameters are registered by pedobarography, usually requiring a research setting for interpretation. The purpose of this study was to evaluate which pedobarographic parameters (adjusted for walking speed and body weight) discriminate between healthy volunteers and patients after ankle or tibiotalocalcaneal arthrodesis. Furthermore, we evaluated which parameters are associated with the American Orthopaedic Foot and Ankle Society (AOFAS) score. Methods: Thirty-five healthy volunteers, 57 patients with ankle and 42 with tibiotalocalcaneal arthrodesis were assessed by AOFAS scores and dynamic pedobarography. The arthrodesis patients were further investi- gated with radiographs. Median follow up was 4 years. Eighteen basic parameters were measured each in the hind-, mid-, and forefoot. For dimension reduction, we represented a pre-selected set of 9 parameters by two indices (load, rollover). We used ordinal logistic and multiple linear regression to address the questions. Findings: The midfoot index of load was the most important pedobarographic predictor (interquartile range odds ratio 100; 95% confidence interval 13, 771) for belonging to the healthy volunteers rather than the ankle or tibiotalocalcaneal arthrodesis groups. Similarly, it was an independent predictor for the AOFAS score (interquartile range effect 5 points; 95% confidence interval 1, 9). Healthy volunteers had a deeper midfoot depression in the force/pressure time graphs compared to patients after arthrodesis. Interpretation: When evaluating foot function after ankle or tibiotalocalcaneal arthrodesis, the interpretation of a large number of pedobarographic parameters can be reduced to the interpretation of the midfoot index of load and the evaluation of the force/pressure time graphs.

Background In the present study, 4 different metallic implant materials, either partly coated or polished, were tested for their osseointegration and biocompatibility in a pelvic implantation model in sheep. Methods Materials to be evaluated were: Cobalt-Chrome (CC), Cobalt-Chrome/Titanium coating (CCTC), Cobalt-Chrome/Zirconium/Titanium coating (CCZTC), Pure Titanium Standard (PTST), Steel, TAN Standard (TANST) and TAN new finish (TANNEW). Surgery was performed on 7 sheep, with 18 implants per sheep, for a total of 63 implants. After 8 weeks, the specimens were harvested and evaluated macroscopically, radiologically, biomechanically (removal torque), histomorphometrically and histologically. Results Cobalt-Chrome screws showed significantly (p = 0.031) lower removal torque values than pure titanium screws and also a tendency towards lower values compared to the other materials, except for steel. Steel screws showed no significant differences, in comparison to cobalt-chrome and TANST, however also a trend towards lower torque values than the remaining materials. The results of the fluorescence sections agreed with those of the biomechanical test. Histomorphometrically, there were no significant differences of bone area between the groups. The BIC (bone-to-implant-contact), used for the assessment of the osseointegration, was significantly lower for cobalt-chrome, compared to steel (p = 0.001). Steel again showed a lower ratio (p = 0.0001) compared to the other materials. Conclusion This study demonstrated that cobalt-chrome and steel show less osseointegration than the other metals and metal-alloys. However, osseointegration of cobalt-chrome was improved by zirconium and/or titanium based coatings (CCTC, TANST, TAN, TANNEW) being similar as pure titanium in their osseointegrative behavior., BMC Musculoskeletal Disorders, 13, ISSN:1471-2474

Charcot medial column and midfoot deformities are associated with rocker bottom foot, recurrent plantar ulceration, and consequent infection. The primary goal of surgical intervention is to realign and stabilize the plantar arch in a shoe-able, plantigrade alignment. Different fixation devices, including screws, plates, and external fixators, can be used to stabilize the Charcot foot; however, each of these methods has substantial disadvantages. To assess the effectiveness of rigid, minimally invasive fixation of the medial column and midfoot, 8 cases of solid intramedullary bolt fixation for symptomatic Charcot neuroarthropathy were reviewed. The patients included 6 males (75%) and 2 females (25%), with a mean age of 63 (range 46 to 80) years. The Charcot foot deformity was caused by diabetic neuropathy in 7 cases (87.5%) and alcoholic neuropathy in 1 (12.5%). The mean duration of postoperative follow-up period was 27 (range 12 to 44) months. The mean radiographic correction of the lateral talar–first metatarsal angle was 15° (range 3° to 19°), and the mean radiographic correction of the dorsal midfoot dislocation was 9 (range −4 to 23) mm. The mean loss of correction of the lateral talar–first metatarsal angle and midfoot dislocation after surgery was 7° (range 0° to 26°) and 1 (range 0 to 7) mm, respectively. No bolt breakage was observed, and no cases of recurrent or residual ulceration occurred during the observation period. Bolt removal was performed in 3 cases (37.5%), 2 (25%) because of axial migration of the bolt into the ankle joint and 1 (12.5%) because of infection. The results of the present review suggest that a solid intramedullary bolt provides reasonable fixation for realignment of the medial column in cases of Charcot neuroarthropathy.

Background: We found treatment of clavicular midshaft fractures using titanium elastic nails (TENs) in combination with postoperative free ROM was associated with a complication rate of 78%. The use of end caps reduced the rate to 60%, which we still considered unacceptably high. Thus, we explored an alternative approach. Questions/purposes: We investigated whether (1) the complication rate could be reduced by cautious lateral advancement of the TENs, intraoperative oblique radiographs to rule out lateral perforation, and limited ROM postoperatively; (2) fluoroscopy time could be reduced; and (3) shoulder function would be reasonable. Patients and Methods: From March 2006 to December 2009, we treated 44 patients with midshaft clavicular fractures with TENs and end caps. In the first group (n = 15), the TEN was advanced laterally using an oscillating drill. The patients were permitted free ROM. In the second group (n = 29), the TEN was advanced by hand, conversion to open reduction followed two failed closed attempts and lateral perforation was checked with an intraoperative oblique radiograph. Furthermore, anteversion and abduction of the shoulder were limited to 90° for the first 6weeks. Minimum followup was 12months (mean, 16.7months; range, 12-28months). Results: The total complication rate was reduced from nine of 15 in the first group to five of 29 in the second group. Medial perforations ceased with the use of the end cap. Fluoroscopy time was reduced from a mean of 10 to 4 minutes by converting to open reduction after two failed closed attempts. All but three patients exhibited full shoulder ROM at three months and these three had a slight deficit of 10° to 20° in anteversion and/or abduction. At last followup, the mean American Shoulder and Elbow Surgeons score was 92 (range, 88-100) and the Disability of the Arm, Shoulder, and Hand score 1.4 (range, 0-12.5). Conclusions: Cautious insertion of the TENs, intraoperative oblique radiographs, and limiting the ROM for 6weeks postoperatively reduced the complication rate. Using TENs with end caps for midshaft clavicular fractures is minimally invasive while associated with comparable complication rates and function to plate osteosynthesis. Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence

Wie bei allen rontgendurchlassigen Verfahren: Einstellung der beiden Verriegelungslocher des Nagels deckungsgleich im Zentralstrahl des Bildwandlers. Zentralstrahl wird Zielstrahl fur orthogrades Einstellen des “Zielinstrumentes” (Abbildung 1). Besonderheit

A structural graft often is needed to fill gaps during reconstructive procedures of the ankle and hindfoot. Autograft, the current gold standard, is limited in availability and configuration and is associated with donor-site morbidity in as much as 48%, whereas the alternative allograft carries risks of disease transmission and collapse. Trabecular metal (tantalum), with a healing rate similar to that of autograft, high stability, and no donor-site morbidity, has been used in surgery of the hip, knee, and spine. However, its use has not been documented in foot and ankle surgery. We retrospectively reviewed nine patients with complex foot and ankle arthrodeses using a tantalum spacer. Minimum followup was 1.9 years (average, 2 years; range, 1.9–2.4 years). Bone ingrowth into the tantalum was analyzed with micro-CT in three of the nine patients. All arthrodeses were fused clinically and radiographically at the 1- and 2 year followups and no complications occurred. The American Orthopaedic Foot and Ankle Society score increased from 32 to 74. The micro-CT showed bony trabeculae growing onto the tantalum. Our data suggest tantalum may be used as a structural graft option for ankle and subtalar arthrodesis. All nine of our patients achieved fusion and had no complications. Using tantalum obviated the need for harvesting of the iliac spine. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Hypothesis Chronic rotator cuff tears are associated with irreversible architectural muscle changes and a high rate of repair failure. The changes observed in man and their irreversibility with a single stage repair can be reproduced in sheep. It was the purpose of this experiment to test the hypothesis that slow, continuous elongation of a retracted musculotendinous unit allows reversal of the currently irreversible structural muscle changes. Materials and methods The infraspinatus tendon of 12 sheep was released using a greater tuberosity osteotomy and allowed to retract for 4 months. Then, a new device was mounted on the scapular spine and used to extend the infraspinatus muscuculotendinous unit transcutaneously by 1 mm per day. Thereafter, the tendon was repaired back to the greater tuberosity. We assessed the muscular architecture using magnetic resonance imaging, macroscopic dissection, histology, and electron microscopy. Fatty infiltration (in Hounsfield units 1/4 HU) and muscular cross-sectional area (in % of the control side) were monitored with computed tomography at tendon release, initiation of elongation, repair, and at sacrifice. Results Sixteen weeks after tendon release, the mean tendon retraction was 29 ± 6 mm (14% of original length, P = .008). In 8 sheep, elongation was achieved as planned (group I), but in 4, the elongation failed technically (group II). The mean traction time was 24 ± 6 days with a mean traction distance of 19 ± 4 mm. At sacrifice, the mean pennation angle in the infraspinatus of group I was not different from the control side (29.8°±7.5° vs. 30°±6°, P = .575). In group II, the pennation angle had increased from 30°±6° to 55°±14° ( P = .035). There was no fatty infiltration at the time of tendon release. After retraction, there was a significant increase in fatty infiltration of the infraspinatus muscle and a decrease of its cross-sectional area to 57% of the contralateral side ( P = .0001). During traction, the degree of fatty infiltration remained unchanged (36 HU to 38 HU, P = .381), and atrophy improved to a muscle square area of 78% of the contralateral side ( P = .0001) in group I. In group II, an increase of fatty infiltration was measured from 36 HU to 28 HU; however, this increase was not significant ( P = .144). Atrophy did not change in group II (57-55%, P = .946). At sacrifice, the remaining muscle mass was 64% in group I and 46% in group II ( P = .019). Discussion Our preliminary results document, that continuous elongation of a retracted, fatty infiltrated and atrophied musculotendinous unit is technically feasible. Conclusion In the sheep, continuous elongation can lead to restoration of normal muscle architecture, to partial reversal of muscle atrophy, and to arrest of the progression of fatty infiltration. Level of evidence Basic science level 2; Prospective comparative therapeutic study.

Background: Chronic ankle instability (CAI) is a common orthopaedic entity in sport. Although other risk factors have been studied extensively, little is known about how it is influenced by the osseous joint configuration. Aim: To study the effect of osseous ankle configuration on CAI. Design: Case–control study, level III. Setting: Radiological examination with measurement of lateral x rays by an independent radiologist using a digital DICOM/PACS system. Patients: A group of 52 patients who had had at least three recurrent sprains was compared with an age-matched and sex-matched control group of 52 healthy subjects. Main outcome measures: The radius of the talar surface, the tibial coverage of the talus (tibiotalar sector) and the height of the talar body were measured. Results: The talar radius was found to be larger in patients with CAI (21.2 (2.4) mm) than in controls (17.7 (1.9) mm; p 95%). The tibiotalar sector, representing the tibial coverage of the talus, was smaller in patients with CAI (80° (5.1°)) than in controls (88.4° (7.2°); p 95%). No significant difference was observed in the height of the talar body between patients with CAI (28.8 (2.6) mm) and controls (27.5 (4.0) mm; p = 0.055). Conclusion: CAI is associated with an unstable osseous joint configuration characterised by a larger radius of the talus and a smaller tibiotalar sector. There is evidence that a higher talus might also play some part, particularly in women.

Background: Total contact casting (TCC) has become established as standard treatment for Wagner grades 1 and 2 diabetic foot ulcers. However, the recurrence rate after TCC is unacceptably high, and a clear concept to prevent recurrences is still lacking. The purpose of this study was to evaluate recurrences and the effectiveness of preventive measures in a group of diabetic patients treated with TCC. Methods: From January of 1999, to June of 2004, 28 patients (20 men and 8 women; average age 63 years) with 34 ulcers were treated using TCC. Thereafter, orthopaedic shoes were provided and patients were followed regularly. Recurrences were treated first by TCC, and operative correction was carried out in patients with an underlying foot deformity. Mean followup was 2.8 (1 to 5) years. Results: Primary TCC treatment lasted 4 (1 to 17) months. Complete healing was achieved in 85% of ulcers; 57% of patients had a total of 26 recurrences, and 18 new ulcers were found in a different area or on the other foot. Sixteen recurrences were treated successfully by TCC, but the rate of new recurrences during followup was 50%. Eight recurrences were treated by operative correction of foot deformities. Most patients stayed ulcer-free thereafter. An unloading shoe was applied twice. No amputations were required. Conclusions: The first TCC showed an effective healing rate of 85%. The high recurrence rate of 57% in the presence of optimal instruction, shoes, and followup suggests that these measures are not sufficient. However, because patients who had operative corrections stayed ulcer-free thereafter, it is suggested that foot deformities should be operatively corrected immediately after primary healing rather than waiting until further recurrences occur.

Medullary nails have only been used with reluctance in the treatment of open fractures since reaming interferes with the cortical circulation. The technique of interlocking offers the interesting possibility of inserting a relatively stiff nail which does not necessarily require reaming. The effects of reaming prior to nail insertion upon the cortical circulation was investigated in the canine tibia. Intravital staining with procion red was used to trace areas of disturbed circulation. Nail insertion without reaming provided clear advantages for the bone's blood supply, while reaming disturbed perfusion in two-thirds of the cortical area and regionally extended through the entire thickness of the cortex. The disturbance without reaming was limited to the inner layer of the cortex and involved only one-third of the cortical cross-section.

Conventional interlocking nails for the femur use an inclined proximal interlocking screw; the AO/ASIF universal interlocking nail utilizes a transverse interlocking screw which is anchored in cortical bone. The transverse position of the screw allows one to employ the nail for either the right or left side. The yield strength of the thinner diameter transverse screw, (thread 4.5 mm. core 3.0 mm) was compared with that of the Grosse-Kempf nail oblique screw (thread 6.3 mm, core 4.5 mm) by testing in cadaver femora to evaluate the risk of fatigue failure. The test, performed using slow loading rates (50 N/s), simulated either a diaphyseal or a subtrochanteric fracture situation. The test rig applied a load corresponding to body weight and pull at the trochanter. Taking the highest load without plastic deformation as a criterion, the mechanical strength of the two screws was evaluated for each fracture situation. The thinner but shorter transverse interlocking screw demonstrated higher strength (4500 N vs. 3000 N; P less than or equal to 0.02) than the thicker inclined screw in the diaphyseal and the subtrochanteric fracture situation (2300 N vs. 1100 N; P less than or equal to 0.06). The biomechanical test showed the transverse screw to have sufficient and superior strength.

A major drawback of conventional fixator systems is the penetration of the fixator pins into the medullary canal. The pins create a direct link between the medullary cavity and the outer environment. The new AO pinless fixator bypasses this disadvantage by clamping its trocar points onto the outer cortex without penetrating it. Thus, exposure and consequent contamination of the medullary cavity does not occur. The clinical use of this easily manageable fixator with no drilling requirement is for tibial fractures in which the general and local conditions are poor or the infrastructure of the clinic is inadequate for primary internal stabilization or both. All options for a later conversion to internal fixation remain open. For highly unstable tibial shaft fractures, the pinless fixator can be applied as an additional, minimally invasive, external, locked system to increase the stability of intramedullary nail fixation. The pinless external fixator can be combined favorably with the standard AO tubular system and is a valuable addition to the existing fixator systems.