B. Schliemann

Medial Patellofemoral Ligament Reconstruction: Fixation Strength of 5 Different Techniques for Graft Fixation at the Patella

PURPOSE To compare the structural properties of 5 different fixation strategies for a free tendon graft at the patella in medial patellofemoral ligament (MPFL) reconstruction under cyclic loading and load to failure testing. METHODS We used porcine patella and flexor tendons. We tested the following fixation techniques: 3.5-mm titanium anchor, transosseous 1-mm braided polyester suture, interference screw fixation, medial bone bridge, and transpatellar tunnels. We preconditioned each graft between 5 and 20 Nm before cyclic loading with 100 Nm for 1,000 cycles was started, and then performed load to failure testing. We recorded maximum load, stiffness, and elongation. RESULTS In the bone bridge group, 60% of all specimens failed during cyclic testing. Fixation by transosseous sutures showed significantly less stiffness compared with all other techniques (P < .05). The bone bridge technique showed significantly lower load to failure compared with all other techniques (P < .05). Differences between the other groups were not significant. CONCLUSIONS Fixation of a free tendon graft by transosseous sutures provides similar load to failure and elongation but less stiffness compared with fixation by anchors, interference screws, or transverse tunnels. Load to failure for the bone bridge technique was significantly lower than that for all other techniques. Furthermore, this fixation technique had a lower load to failure than that of the native MPFL. CLINICAL RELEVANCE Fixation of soft tissue grafts at the patella by 1-mm braided polyester suture provides adequate fixation strength without implants in the patella, which might cause soft tissue irritation. Further studies will have to show if the lesser stiffness of this technique causes problems in the clinical setting or if this laxity might even be an advantage because it makes this reconstruction more forgiving concerning overtensioning the graft. Significantly lower load to failure of the bone bridge technique should be considered in postoperative treatment.

Accidental Perforation of the Lateral Femoral Cortex in ACL Reconstruction: An Investigation of Mechanical Properties of Different Fixation Techniques

PURPOSE The aim of this study was to evaluate the mechanical properties of anterior cruciate ligament (ACL) reconstruction using the medial portal technique with cortical fixation and hybrid fixation after penetration of the lateral cortex by use of different drill sizes. METHODS In this biomechanical study a porcine in vitro model was used. The testing protocol consisted of a cyclic loading protocol (1,000 cycles, 50 and 250 N) and subsequent ultimate failure testing. Number of cyclic loadings survived, stiffness, yield load, maximum load, and graft elongation, as well as failure mode, were analyzed after ACL reconstruction with 5- to 9-mm soft-tissue grafts. In the control group, conventional penetration of the lateral cortex with a 4.5-mm drill and cortical fixation were performed. In the tested groups, the lateral cortex was penetrated with a drill matching the graft size. In the first part of the study, we used cortical fixation. In the second part, we used hybrid fixation with an interference screw. RESULTS In the first part of the study, ACL reconstruction with 5- to 6-mm perforation of the lateral cortex showed no significant differences in ultimate failure load after cyclic loading compared with the control group (P > .05). Specimens with reconstruction with 7- to 9-mm perforation of the lateral cortex and cortical fixation did not survive the cyclic loading protocol. In the second part of the study, with a hybrid fixation technique, ultimate failure testing after cyclic loading of specimens with 7- to 9-mm penetration showed no significant differences in tested parameters compared with the control group (P > .05). CONCLUSIONS After penetration of the lateral cortex with a drill size of more than 6 mm, cortical ACL fixation results in poor mechanical properties. Hybrid fixation increases the mechanical properties significantly after penetration with a 7- to 9-mm drill. CLINICAL RELEVANCE We advise caution to avoid penetration of the lateral femoral cortex when using cortical flip-button fixation. In case of accidental perforation of the lateral cortex with a diameter greater than 6 mm, we recommend performing hybrid fixation.

Comparison between conservative and surgical treatment of midshaft clavicle fractures: Outcome of 151 cases

INTRODUCTION Midshaft clavicle fractures comprise up to 15% of all adult upper extremity fractures and account for 76% of all clavicle fractures. The treatment of choice remains controversial. The aim of our retrospective study was to compare the outcome of the surgical and conservative procedure in a trauma care unit (single center study). MATERIAL AND METHODS In a cohort of 151 (mean age 36,1y/male 115/female 36) cases, between 2005 and 2009, 70 patients (46.4%) were treated conservatively (mean age 40.8y) and 81 (53.6%) underwent either surgical treatment with a locking compression plate (n=73/mean age 40.3y) or an intramedullary nail system (n=8, mean age 27.1y). Mean follow up was 15 months. Nine patients (5.9%) were lost to follow-up, due to poor compliance. The clinical outcome was assessed by the Disability of Arm, Shoulder and Hand (DASH) score and the Constant shoulder score. RESULTS The average DASH score was 7.3 and the Constant score measured 91.7 in the surgical group. The conservative group achieved a DASH score of 11.1 and a Constant score of 88.1. The clinical scores showed a significant superiority for the benefit of the surgical treatment for the DASH (p=0.037) and Constant score (p=0.036). Totally nine patients had a non-union in the conservative group and six a hardware failure in the surgical group which were revised. DISCUSSION The treatment options for midshaft clavicle fractures have to be discussed carefully for each patient with regard to the non-union risk, function, cosmesis and revision surgery. CONCLUSION Both therapeutic modalities demonstrated comparable efficacy. For active and younger patients we would favour a surgical treatment due to the short time of rehabilitation, the return to sport activities and the high non-union rate after conservative treatment.

Dynamische intraligamentäre Stabilisierung frischer Rupturen des vorderen Kreuzbandes (Ligamys)

ZusammenfassungDie Ersatzplastik des vorderen Kreuzbandes (VKB) mittels körpereigener Sehne hat sich als Standardverfahren in der Behandlung der VKB-Ruptur etabliert. Dennoch wurden immer wieder Versuche unternommen, das frisch rupturierte VKB zu nähen. Die Ergebnisse waren jedoch eher enttäuschend. Die dynamische intraligamentäre Stabilisierung (DIS) wurde entwickelt, um die biomechanische Stabilität nach primärer Naht des VKB zu gewährleisten und somit eine stabile Einheilung zu ermöglichen. Im Gegensatz zur einfachen Augmentation mittels nichtresorbierbarer Fäden wird bei der DIS ein Federmechanismus verwendet, um der Anisometrie des VKB gerecht zu werden und die Tibia über den gesamten Bewegungsumfang in der hinteren Schublade zu halten. Erste biomechanische und klinische Studien sind vielversprechend, eine erfolgreiche Wiederherstellung der Kniegelenkkinematik ist möglich. Weitere Studien sind allerdings notwendig, um die Wertigkeit dieses neuen Verfahrens für den klinischen Alltag zu belegen.AbstractAnterior cruciate ligament (ACL) reconstruction with the use of autologous tendon grafts is the gold standard in the treatment of ACL instability; however, many different techniques have been proposed to suture freshly ruptured ACLs. Unfortunately, the rate of recurrent instability is high. A new technique, dynamic intraligamentary stabilization (DIS), was developed to restore biomechanical stability after primary ACL repair and therefore to allow stable healing. In order to compensate for the anisometry of the ACL, in contrast to simple augmentation a spring mechanism is used in DIS that helps to maintain the tibia in a posterior drawer position during all degrees of flexion. Initial results of biomechanical and clinical studies are promising, indicating that reconstruction of knee joint kinematics after ACL repair with DIS is possible; however, further clinical studies are required to determine its usefulness in the clinical setting.

Endoprothetik nach Trauma

ZusammenfassungDie Indikation für die Prothesenimplantation nach Trauma ergibt sich in der Regel aus der Schwere und dem Typ der Fraktur sowie dem hohen Alter des Patienten. Somit ist die Ausgangslage für den operativen Eingriff allein aufgrund dieser Bedingungen deutlich schlechter als bei der primären endoprothetischen Versorgung degenerativer Gelenkerkrankungen. Auch die Planung der Operation erfordert eine sensitivere und meist aufwändigere Diagnostik als in der elektiven Situation, zudem geht die Prothesenimplantation nach Trauma mit einer höheren Komplikationsrate einher. Somit stellen sich folgende Fragen, die im vorliegenden Beitrag behandelt werden: Ist die notfallmäßige endoprothetische Versorgung nach Fraktur vertretbar? Wie sollte der Patient aufgeklärt werden? Stellt die endoprothetische Versorgung immer eine „Programmoperation“ dar und wann ist folglich der günstigste Operationszeitpunkt? Gilt der elektive Versorgungsansatz auch für die einfache mediale Schenkelhalsfraktur als klassische Indikation für die Endoprothesenversorgung nach Knochenbruch? Welches sind die operativen Besonderheiten der endoprothetischen Frakturversorgung und welcher Chirurg kann und sollte diesen Eingriff durchführen?AbstractThe indication for arthroplasty following trauma is generally established on the basis of the severity and type of the fracture, as well as on patient age. Thus, the initial situation in terms of surgery, as a result of these conditions alone, is significantly worse than in the case of primary endoprosthetic treatment of degenerative joint disease. Surgical planning also requires a more sensitive and usually more intensive diagnostic workup than for elective surgery, in addition to which arthroplasty following trauma is associated with a higher complication rate. For this reason, the present article examines the following questions: Is emergency endoprosthetic treatment following fracture justifiable? How should the procedure be explained to the patient? Does endoprosthetic treatment always represent “programmed surgery” and, if so, when is the optimal time for surgery? Does elective treatment even for simple medial femoral neck fractures count as a classic indication for endoprosthetic treatment following bone fracture? What are the particular surgical features of endoprosthetic fracture treatment and which surgeon can and should perform this type of surgery?

Die distale Humerusfraktur – wann und welche Osteosynthese?

ZusammenfassungHintergrundFrakturen des distalen Humerus sind für den Unfallchirurgen nach wie vor eine Herausforderung. Trotz zahlreicher Innovationen im Hinblick auf Implantatdesign und Operationstechniken sind die Ergebnisse insbesondere bei komplexeren Frakturen mit höhergradigen Weichteilschäden nicht immer zufriedenstellend. Zahlreiche Komorbiditäten in einem immer älter werdenden Patientenkollektiv erschweren das perioperative Management und tragen zur hohen Komplikationsrate bei.MethodenWährend bei einfachen, nur partiell intraartikulären Frakturen die Schraubenosteosynthese ihren Stellenwert hat, ist die winkelstabile Doppelplattenosteosynthese mittlerweile der Goldstandard in der Versorgung intraartikulärer distaler Humerusfrakturen. Als Standardzugang hat sich hier die Exposition des Gelenks über eine Olekranonosteotomie bewährt. Neben der Plattenosteosynthese hat aber auch der externe Fixateur eine Bedeutung, insbesondere im Rahmen der Primärversorgung bei offenen Frakturen.SchlussfolgerungEin anerkannter Therapiealgorithmus existiert nicht und die Wahl des geeigneten Therapieverfahrens muss immer individuell und an den Patienten angepasst getroffen werden.AbstractBackgroundThe surgical treatment of comminuted fractures of the distal humerus remains a challenging problem for orthopedic surgeons. Despite improved implant designs and new developments in surgical techniques these fracture are associated with high complication rates and poor clinical outcomes. Comorbidities, such as diabetes and osteopenia in combination with severe soft tissue damage worsen the healing capacity and make the rehabilitation more difficult.MethodsInternal fixation with locking plates has become the current gold standard in the operative treatment of intra-articular fractures of the distal humerus, although locking screw osteosynthesis still has a place for simple, only partial intra-articular fractures. The standard approach has been established as exposure of the joint by olecranon osteotomy; however, complex fractures with severe soft tissue damage may require primary external fixation prior to definitive treatment.ConclusionTo date, there is still no generally accepted treatment algorithm and the decision on how to treat these fractures has to made on an individual basis, taking fracture patterns, soft tissue damage, general condition of the patient and comorbidities into account.