Walter Dick

The role of ankle arthroscopy in the treatment strategies of osteochondritis dissecans lesions of the talus.

Thirty-six cases of osteochondritis dissecans (OD) of the talus were diagnosed among 413 ankle arthroscopies performed within a period of six years. In 52.8% of the cases the OD was found on the medial and in 41.7% on the lateral talus. 53.3% of the lateral OD presented stage III and IV lesions while only 26.3% of the medial OD were to be graded stage III and IV. Patients with grade I and II lesions had mostly excellent outcome scores between 90 and 100. However, four patients with medial OD at less severe stages who were treated surgically, showed a particularly unfavorable outcome with scores between 11 and 36. All these patients needed either ankle arthrodesis or total ankle joint replacement. For stage II and III medial lesions, our experience has led to a more conservative approach due to the unfavorable outcome of surgical treatment observed in these patients. Despite the usefulness of MRI in the diagnosis of OD of the talus, arthroscopy has been proven to represent a very helpful diagnostic tool in assessing extent and in particular stability and integrity of the osteochondritic lesion. Apart from enabling the various minimally invasive surgical treatment options, ankle arthroscopy should be performed in all patients with OD of the talus in order to help define the treatment strategy and avoid unnecessary surgery on stable lesions.

Nonmodular flexible press-fit cup in primary total hip arthroplasty : 15-year followup

The key rationale for a nonmodular flexible press-fit cup was to maximize long-term stability with a cementless, porous metal-coated cup that is low in stiffness (no metal shell) and to achieve fixation solely through biradial eccentricity between the cup and the acetabular cavity. We asked whether the promising results achieved at 5 and 10 years would be maintained at 15 years. We reviewed 261 patients who received the first 280 Morscher Press-Fit™ Cups. One hundred twenty patients (126 hips) died. One hundred one patients (112 hips) had a clinical and radiographic followup after a minimum of 13.5 years (mean, 14.7 years; range, 13.5-17.0 years). Twenty-four patients with 26 hips were clinically examined or interviewed by telephone. Three of the 101 patients were lost to followup. We judged the results excellent or good in 96% of the hips. The 15-year overall survivorship was 95.3% and with the end point of aseptic loosening, the survivorship was 97.5%. Wear was greater in cups with an inclination greater than 45° and in metal-polyethylene pairings compared with ceramic-polyethylene pairings. This cup design performs well over the long term. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Muscular lower leg asymmetry in middle-aged people

Background: The purpose of this study was to determine whether muscular asymmetries were present in the lower legs of recreationally active middle-aged people grouped by leg dominance. Methods: Twelve healthy middle-aged subjects were analyzed bilaterally. The clinical variables included leg dominance, sports level, range of motion, lower leg alignment, calf circumference, and AOFAS (American Orthopaedic Foot and Ankle Society) ankle score. The biomechanical variables included maximal voluntary isometric ankle joint torque and surface electromyography (EMG) with determination of mean EMG frequency and intensity of four lower leg muscles: anterior tibial (AT), medial gastrocnemius (MG), soleus (SO), and peroneus longus (PL). Results: The mean EMG frequency was significantly lower in the dominant leg for the AT (dominant, 148.6 Hz; nondominant, 157.8 Hz) and MG muscles (dominant, 183.9 Hz; nondominant, 196.8 Hz). A significantly higher plantarflexion torque was found in the dominant leg (27.1 Nm) compared to the nondominant leg (22.9 Nm). Higher (not significant) dorsiflexion torque was found in the dominant leg (dominant, 27.3 Nm; nondominant, 24.8 Nm). The calf circumference was marginally significantly higher (p = 0.039) in the dominant leg (34.2 cm; nondominant leg, 33.8 cm). The dominant leg had a higher but not significantly different mean EMG intensity for all four muscles. Conclusions and Clinical Relevance: Differences in muscle EMG and torque were found between the dominant and nondominant lower leg. These results might be applicable to treatment, rehabilitation, and future research of lower leg and foot and ankle disorders.

Muscle biomechanics in total ankle replacement

ZusammenfassungDas Ziel dieser orthopädisch-biomechanischen Studie war die Evaluation der Muskelfunktion von Patienten, bei welchen infolge unilateraler, schwerer Arthrose am oberen Sprunggelenk (OSG) eine Prothese eingesetzt wurde.Bei 10xa0Patienten wurde vor und 1xa0Jahr nach Implantation einer OSG-Prothese eine orthopädische und biomechanische Untersuchung durchgeführt. Dabei wurden der Schmerzscore, der „American Orthopaedic Foot and Ankle Society“- (AOFAS-)Ankle-Score, der Bewegungsumfang (ROM) des Sprunggelenks und der Unterschied zwischen dem Umfang des Unterschenkels des betroffenen und des kontralateralen gesunden Beins gemessen. Die biomechanische Beurteilung bestand aus einer simultanen Messung des maximal willkürlichen, isometrischen Drehmoments bei Plantarflexion und Dorsalextension des OSG sowie aus einem Oberflächenelektromyogramm (EMG; mittlere Frequenz und Intensität) von 4 Unterschenkelmuskeln: Tibialis anterior (TA), Gastrocnemius medialis (GM), Soleus (SO) und Peroneus longus (PL).Im Vergleich zur präoperativen Evaluation verbesserten sich der Schmerzscore von 6,7 auf 0,8xa0Punkte, der AOFAS-Ankle-Score von 35,6 auf 92,3xa0Punkte und der ROM nach Implantation der OSG-Prothese signifikant. Die mittlere Differenz des Unterschenkelumfangs zwischen den beiden Beinen nahm von 2,2xa0cm auf 1,4xa0cm ab. Dies war jedoch nicht signifikant. Das mittlere Drehmoment des betroffenen Sprunggelenks bei Dorsalextension stieg von 17,0 auf 25,8xa0Nm und bei Plantarflexion von 15,7 auf 24,6xa0Nm signifikant an. Bei der 1-Jahres-Nachkontrolle war die mittlere EMG-Frequenz in allen atrophischen Muskeln tiefer als bei den gesunden Muskeln der kontralateralen Seite. Ein Unterschied der mittleren EMG-Intensität zur kontralateralen gesunden Seite konnte nicht verifiziert werden.Daraus kann gefolgert werden, dass Patienten mit symptomatischer OSG-Arthrose mit einer Prothese eine bessere Funktion erlangen; 1xa0Jahr nach der Operation entspricht dies jedoch nicht dem Ausmaß derjenigen des kontralateralen gesunden Beins.AbstractThe purpose of this orthopaedic-biomechanical study was to evaluate the muscle function in total ankle replacement (TAR) patients 1xa0year after surgery.Ten patients underwent a combined clinical and muscle biomechanical assessment prior to implantation and at the 1-year follow-up. Pain score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle score, ankle range of motion (ROM), and calf circumference difference between the affected leg and contralateral healthy leg were assessed. Biomechanically, isometric maximal voluntary torque for ankle dorsiflexion and plantar flexion was measured simultaneously with surface electromyography of four lower leg muscles.At follow-up, a significant improvement of the pain score (from 6.7 to 0.8 points), AOFAS ankle score (from 35.6 to 92.3 points), and ROM could be shown. Not significantly, the mean calf circumference difference between legs decreased from 2.2 to 1.4xa0cm. However, a significant increase was seen in the mean dorsiflexion (from 17.0 to 25.8xa0Nm) and plantar flexion torque (15.7 to 24.6xa0Nm) of the TAR-treated ankle. The mean EMG frequency content of the affected lower leg at TAR follow-up was lower than in the muscles of the contralateral healthy side. In contrast, the mean EMG intensity at TAR follow-up in side-comparison was statistically the same for all muscles.Ankle OA patients have better muscle function with TAR than under the arthritic condition, but they do not reach the normal level of the contralateral healthy leg 1xa0year after surgery.The purpose of this orthopaedic-biomechanical study was to evaluate the muscle function in total ankle replacement (TAR) patients 1 year after surgery. Ten patients underwent a combined clinical and muscle biomechanical assessment prior to implantation and at the 1-year follow-up. Pain score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle score, ankle range of motion (ROM), and calf circumference difference between the affected leg and contralateral healthy leg were assessed. Biomechanically, isometric maximal voluntary torque for ankle dorsiflexion and plantar flexion was measured simultaneously with surface electromyography of four lower leg muscles. At follow-up, a significant improvement of the pain score (from 6.7 to 0.8 points), AOFAS ankle score (from 35.6 to 92.3 points), and ROM could be shown. Not significantly, the mean calf circumference difference between legs decreased from 2.2 to 1.4 cm. However, a significant increase was seen in the mean dorsiflexion (from 17.0 to 25.8 Nm) and plantar flexion torque (15.7 to 24.6 Nm) of the TAR-treated ankle. The mean EMG frequency content of the affected lower leg at TAR follow-up was lower than in the muscles of the contralateral healthy side. In contrast, the mean EMG intensity at TAR follow-up in side-comparison was statistically the same for all muscles. Ankle OA patients have better muscle function with TAR than under the arthritic condition, but they do not reach the normal level of the contralateral healthy leg 1 year after surgery.

Muskuläre Biomechanik in der Sprunggelenkprothetik

ZusammenfassungDas Ziel dieser orthopädisch-biomechanischen Studie war die Evaluation der Muskelfunktion von Patienten, bei welchen infolge unilateraler, schwerer Arthrose am oberen Sprunggelenk (OSG) eine Prothese eingesetzt wurde.Bei 10xa0Patienten wurde vor und 1xa0Jahr nach Implantation einer OSG-Prothese eine orthopädische und biomechanische Untersuchung durchgeführt. Dabei wurden der Schmerzscore, der „American Orthopaedic Foot and Ankle Society“- (AOFAS-)Ankle-Score, der Bewegungsumfang (ROM) des Sprunggelenks und der Unterschied zwischen dem Umfang des Unterschenkels des betroffenen und des kontralateralen gesunden Beins gemessen. Die biomechanische Beurteilung bestand aus einer simultanen Messung des maximal willkürlichen, isometrischen Drehmoments bei Plantarflexion und Dorsalextension des OSG sowie aus einem Oberflächenelektromyogramm (EMG; mittlere Frequenz und Intensität) von 4 Unterschenkelmuskeln: Tibialis anterior (TA), Gastrocnemius medialis (GM), Soleus (SO) und Peroneus longus (PL).Im Vergleich zur präoperativen Evaluation verbesserten sich der Schmerzscore von 6,7 auf 0,8xa0Punkte, der AOFAS-Ankle-Score von 35,6 auf 92,3xa0Punkte und der ROM nach Implantation der OSG-Prothese signifikant. Die mittlere Differenz des Unterschenkelumfangs zwischen den beiden Beinen nahm von 2,2xa0cm auf 1,4xa0cm ab. Dies war jedoch nicht signifikant. Das mittlere Drehmoment des betroffenen Sprunggelenks bei Dorsalextension stieg von 17,0 auf 25,8xa0Nm und bei Plantarflexion von 15,7 auf 24,6xa0Nm signifikant an. Bei der 1-Jahres-Nachkontrolle war die mittlere EMG-Frequenz in allen atrophischen Muskeln tiefer als bei den gesunden Muskeln der kontralateralen Seite. Ein Unterschied der mittleren EMG-Intensität zur kontralateralen gesunden Seite konnte nicht verifiziert werden.Daraus kann gefolgert werden, dass Patienten mit symptomatischer OSG-Arthrose mit einer Prothese eine bessere Funktion erlangen; 1xa0Jahr nach der Operation entspricht dies jedoch nicht dem Ausmaß derjenigen des kontralateralen gesunden Beins.AbstractThe purpose of this orthopaedic-biomechanical study was to evaluate the muscle function in total ankle replacement (TAR) patients 1xa0year after surgery.Ten patients underwent a combined clinical and muscle biomechanical assessment prior to implantation and at the 1-year follow-up. Pain score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle score, ankle range of motion (ROM), and calf circumference difference between the affected leg and contralateral healthy leg were assessed. Biomechanically, isometric maximal voluntary torque for ankle dorsiflexion and plantar flexion was measured simultaneously with surface electromyography of four lower leg muscles.At follow-up, a significant improvement of the pain score (from 6.7 to 0.8 points), AOFAS ankle score (from 35.6 to 92.3 points), and ROM could be shown. Not significantly, the mean calf circumference difference between legs decreased from 2.2 to 1.4xa0cm. However, a significant increase was seen in the mean dorsiflexion (from 17.0 to 25.8xa0Nm) and plantar flexion torque (15.7 to 24.6xa0Nm) of the TAR-treated ankle. The mean EMG frequency content of the affected lower leg at TAR follow-up was lower than in the muscles of the contralateral healthy side. In contrast, the mean EMG intensity at TAR follow-up in side-comparison was statistically the same for all muscles.Ankle OA patients have better muscle function with TAR than under the arthritic condition, but they do not reach the normal level of the contralateral healthy leg 1xa0year after surgery.The purpose of this orthopaedic-biomechanical study was to evaluate the muscle function in total ankle replacement (TAR) patients 1 year after surgery. Ten patients underwent a combined clinical and muscle biomechanical assessment prior to implantation and at the 1-year follow-up. Pain score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle score, ankle range of motion (ROM), and calf circumference difference between the affected leg and contralateral healthy leg were assessed. Biomechanically, isometric maximal voluntary torque for ankle dorsiflexion and plantar flexion was measured simultaneously with surface electromyography of four lower leg muscles. At follow-up, a significant improvement of the pain score (from 6.7 to 0.8 points), AOFAS ankle score (from 35.6 to 92.3 points), and ROM could be shown. Not significantly, the mean calf circumference difference between legs decreased from 2.2 to 1.4 cm. However, a significant increase was seen in the mean dorsiflexion (from 17.0 to 25.8 Nm) and plantar flexion torque (15.7 to 24.6 Nm) of the TAR-treated ankle. The mean EMG frequency content of the affected lower leg at TAR follow-up was lower than in the muscles of the contralateral healthy side. In contrast, the mean EMG intensity at TAR follow-up in side-comparison was statistically the same for all muscles. Ankle OA patients have better muscle function with TAR than under the arthritic condition, but they do not reach the normal level of the contralateral healthy leg 1 year after surgery.

PRÄVENTION: Prävention der akuten Distorsion und chronischen Instabilität des oberen Sprunggelenkes

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.

MICHAEL-JÄGER-PREIS 2001

Zusammenfassung Ziel der vorliegenden Studie war es, an einem in vivo -Modell das Rehabilitationspotential des Tibialis posterior-Muskels wie auch die Sehnenheilung zu bestimmen. 14 Patienten wurden einheitlich mit Naht der Sehne und der Bander sowie einer Kalkaneusverlangerungsosteotomie versorgt. Nach 47 (24–76) Monaten erhohte sich der AOFAS-Hindfoot-Score von 49,1 (32–60) Punkten auf 93,1 (76–100) Punkte. Weder die Dauer der Symptome noch das funktionelle Resultat korrelierten mit der maximalen Muskelkraft. Die Patientenzufriedenheit und die sportliche Aktivitat hingen weder von der Muskelkraft noch vom Muskelquerschnitt ab. In jedem Fall scheint der Aufwand einer verspateten Sehnenrekonstruktion selbst bei nachweislich schlechter Gewebequalitat und fortgeschrittener Verfettung des Muskels gerechtfertigt.