Zusammenfassung Der „AGA Therapiealgorithmus der Patellainstabilität“ (ATAPI) basiert auf der klinischen Untersuchung, der Bildgebung und dem daraus resultierenden Risikoprofil. Im ersten Schritt wird eine mögliche Flake-Fraktur mittels Bildgebung detektiert. Im zweiten Schritt wird das individuelle Risiko einer Reluxation in Abhängigkeit der vorliegenden anatomischen und epidemiologischen Parameter erfasst. Bei niedrigem Risikoprofil ohne Flake-Fraktur wird primär die konservative Therapie empfohlen. Bei vorhandener Flake-Fraktur wird eine Refixation des Fragments angestrebt. Eine zusätzliche Rekonstruktion des medialen patellofemoralen Ligaments (MPFL) senkt das Reluxationsrisiko deutlich und wird auch als Grundpfeiler der operativen Therapie gesehen. Je nach Risikoprofil werden weitere Zusatzeingriffe in Erwägung gezogen. Somit besteht auch bei Patellaluxation ohne Flake-Fraktur aber hohem Risikoprofil die Indikation zur Operation.

Background Patellar instability has a high incidence and occurs particularly in young and female patients. If the patella dislocates for the first time, treatment is usually conservative. However, this cautious approach carries the risk of recurrence and of secondary pathologies such as osteochondral fractures. Moreover, there is also risk of continuous symptoms apparent, as recurrent patella dislocation is related to patellofemoral osteoarthritis as well. An initial surgical treatment could possibly avoid these consequences of recurrent patella dislocation. Methods A prospective, randomized-controlled trial design is applied. Patients with unilateral first-time patella dislocation will be considered for participation. Study participants will be randomized to either conservative treatment or to a tailored patella stabilizing treatment. In the conservative group, patients will use a knee brace and will be prescribed outpatient physical therapy. The surgical treatment will be performed in a tailored manner, addressing the pathologic anatomy that predisposes to patella dislocation. The Banff Patellofemoral Instability-Instrument 2.0, recurrence rate, apprehension test, joint degeneration, and the Patella Instability Severity Score will serve as outcome parameters. The main analysis will focus on the difference in change of the scores between the two groups within a 2-year follow-up. Statistical analysis will use linear mixed models. Power analysis was done for the comparison of the two study arms at 2-year follow-up with regard to the BPII Score. A sample size of N = 64 per study arm (128 overall) provides 80% power (alpha = 0.05, two-tailed) to detect a difference of 0.5 standard deviations in a t-test for independent samples. Discussion Although several studies have already dealt with this issue, there is still no consensus on the ideal treatment concept for primary patellar dislocation. Moreover, most of these studies show a unified surgical group, which means that all patients were treated with the same surgical procedure. This is regarded as a major limitation as surgical treatment of patella dislocation should depend on the patient’s anatomic pathologies leading to patellar instability. To our knowledge, this is the first study investigating whether patients with primary patella dislocation are better treated conservatively or operatively with tailored surgery to stabilize the patella. Trial registration The study will be prospectively registered in the publicly accessible database www.ClinicalTrials.gov .

Acute patellar luxation is a typical injury in adolescence with a higher risk of reluxation compared to adults. Despite the multitude of surgical options the treatment represents a special situation due to the open growth plates. The occurrence of a primary dislocation necessitates an exact clarification of the risks, even in children and adolescents. In the case of an unfavorable risk profile, a primary operative stabilization must be contemplated, taking the risk factors into consideration as an untreated instability can lead to irreversible chondral damage of the patellofemoral joint, especially in early adulthood.

Die Luxation der Patella ist eine typische Erkrankung der Adoleszenz mit im Vergleich zu Erwachsenen höherem Reluxationsrisiko. Die Behandlung stellt aufgrund der offenen Wachstumsfugen trotz der Vielzahl der operativen Möglichkeiten eine Besonderheit dar. Bei Auftreten einer Erstluxation ist auch bei Kindern und Jugendlichen eine genaue Risikoabklärung erforderlich. Liegt ein ungünstiges Risikoprofil vor, muss eine primäre operative Stabilisierung unter Berücksichtigung der Risikofaktoren in Erwägung gezogen werden, da eine unbehandelte Instabilität bereits im frühen Erwachsenenalter zu irreversiblen Knorpelschäden am Patellofemoralgelenk führen kann.

Stabile Rezentrierung der Patella durch die kombinierte Rekonstruktion des MPFL und vertiefende Trochleaplastik.

The double-row rotator cuff repair is discussed controversially. Despite improved biomechanical properties, reduced re-tear rates and higher costs, no significant difference compared to single-row fixation in the clinical results is found. Mid-term results of an open double-row fixation with titanium anchor screws are presented.237 patients (m = 142, f = 95, median age: 56.3 years) were operated in 2007 with this technique by the senior author (M. G.). Preoperatively, 2 years and 4,5 years postoperatively a subjective shoulder score (SSG) with follow-up rates of 86, 87 and 83 %, was evaluated. 5.1 years postoperatively an objective evaluation of 131 patients using the Constant-Murley scores (CS), the simple shoulder tests (SST), Gerber's shoulder value and the evaluation with school grades followed. The integrity of the cuff was checked with ultrasound. The absolute (re-tears and partial re-tears) and the relative (re-tears, partial re-tears, thinning and thickening of the cuff) re-tear rates were evaluated.In SSG a highly significant improvement from 51 to 83 points was found (p < 0.001). In CS 80 points (min.: 18; max.: 100), and in SST 11 points (min.: 2; max.: 12) were achieved. The shoulder value of Gerber increased significantly from preoperative 28.1 to 84.5 % 5.1 years postoperative (p < 0.001).The absolute re-tear rate, evaluated in ultrasound was 7.6 %, the relative re-tear rate 17.6 %. For primary rotator cuff reconstructions a higher CS with 82 points and a lower relative re-tear rate with 10.5 % were found. The patient's age had no significant influence on the clinical outcome. The rupture size showed a significant impact on the re-tear rate and the scores (p < 0.05). Between the operated and healthy shoulder neither strength nor mobility were found to be significantly different. Men reached a highly significant better strength than women (p < 0.001) which also resulted in a significantly better outcome in the CS (p < 0.01). The costs for open titanium transfixation technique with 330 € per case are markedly less than for arthroscopic suture bridge technique with 600 to 1000 € per case.Open double-row cuff repair with titanium screws is a safe and cost effective technique with a low re-tear rate with comparable clinical results regarding open and arthroscopic procedures.

BACKGROUND:The double-row rotator cuff repair is discussed controversially. Despite improved biomechanical properties, reduced re-tear rates and higher costs, no significant difference compared to single-row fixation in the clinical results is found. Mid-term results of an open double-row fixation with titanium anchor screws are presented.MATERIAL AND METHODS:237 patients (m = 142, f = 95, median age: 56.3 years) were operated in 2007 with this technique by the senior author (M. G.). Preoperatively, 2 years and 4,5 years postoperatively a subjective shoulder score (SSG) with follow-up rates of 86, 87 and 83 %, was evaluated. 5.1 years postoperatively an objective evaluation of 131 patients using the Constant-Murley scores (CS), the simple shoulder tests (SST), Gerber's shoulder value and the evaluation with school grades followed. The integrity of the cuff was checked with ultrasound. The absolute (re-tears and partial re-tears) and the relative (re-tears, partial re-tears, thinning and thickening of the cuff) re-tear rates were evaluated.RESULTS:In SSG a highly significant improvement from 51 to 83 points was found (p < 0.001). In CS 80 points (min.: 18; max.: 100), and in SST 11 points (min.: 2; max.: 12) were achieved. The shoulder value of Gerber increased significantly from preoperative 28.1 to 84.5 % 5.1 years postoperative (p < 0.001).The absolute re-tear rate, evaluated in ultrasound was 7.6 %, the relative re-tear rate 17.6 %. For primary rotator cuff reconstructions a higher CS with 82 points and a lower relative re-tear rate with 10.5 % were found. The patient's age had no significant influence on the clinical outcome. The rupture size showed a significant impact on the re-tear rate and the scores (p < 0.05). Between the operated and healthy shoulder neither strength nor mobility were found to be significantly different. Men reached a highly significant better strength than women (p < 0.001) which also resulted in a significantly better outcome in the CS (p < 0.01). The costs for open titanium transfixation technique with 330 € per case are markedly less than for arthroscopic suture bridge technique with 600 to 1000 € per case.CONCLUSION:Open double-row cuff repair with titanium screws is a safe and cost effective technique with a low re-tear rate with comparable clinical results regarding open and arthroscopic procedures.

Trochlear dysplasia is an important aetiological factor for the development of patellofemoral instability (PFI). The aim of the study was to identify the arthroscopic morphology of trochlear dysplasia that can be helpful when planning operative treatment for PFI.

Trochlear dysplasia is considered to be one of the major factors causing patellofemoral instability (PFI). Dejour’s classification is widely used to assess the severity of trochlear dysplasia. Additionally, in current literature, different quantitative parameters are recommended to distinguish between a normal trochlea and a dysplastic trochlea. In order to achieve a more objective evaluation of the trochlea, the aim of this study was to evaluate whether specific measurements of the femoral trochlea can be assigned to the qualitative classification system of Dejour.

Femoral osteotomies are the preferred treatment in significant torsional deformity of the femur. The influence of torsional osteotomies on frontal plane alignment is poorly understood. Therefore, the aim of the present study was to evaluate the effects of external derotational osteotomies on proximal, mid-shaft and distal levels onto frontal plane alignment.

Nail-patella syndrome (NPS) or hereditary onycho-osteodysplasia is a relatively rare autosomal dominant disorder with the classic tetrad of fingernail abnormalities, hypoplastic patellae, radial head dislocation and iliac horns. The anatomic abnormalities in NPS often lead to subluxation or dislocation of the patellae causing knee instability and pain. Although most existing literature regarding the knee manifestation of this syndrome has focused on the clinically and radiological changes, only a few articles discussed the surgical treatment. This study reports the clinical, radiological and arthroscopical findings and a 24-month follow-up after operative stabilisation considering the underlying pathomorphology of malformative patellar instability in an 11-year-old girl. The findings of this study confirm the unique pathology of NPS with a synovial band preventing the engagement of the patella into the trochlear groove. Nail-patella syndrome is a rare disorder and has to be considered in cases with untypical patella dislocation. The underlying pathology differs completely from patients with patellofemoral instability. The aim of orthopaedic surgery should be correction of the underlying pathology with resection of the synovial band and an additional realignment of the patella by recentering of the quadriceps muscle. Considering the underlying pathology, good clinical results can be expected.

Nail-patella syndrome (NPS) or hereditary onycho-osteodysplasia is a relatively rare autosomal dominant disorder with the classic tetrad of fingernail abnormalities, hypoplastic patellae, radial head dislocation and iliac horns. The anatomic abnormalities in NPS often lead to subluxation or dislocation of the patellaeca causing knee instability and pain. Although most existing literature regarding the knee manifestation of this syndrome has focused on the clinically and radiological changes, only a few articles discussed the surgical treatment. This study reports the clinical, radiological and arthroscopical findings and a 24-month follow-up after operative stabilisation considering the underlying pathomorphology of malformative patellar instability in an 11-year-old girl. The findings of this study confirm the unique pathology of NPS with a synovial band preventing the engagement of the patella into the trochlear groove. NPS is a rare disorder and has to be considered in cases with untypical patella dislocation. The underlying pathology differs completely from patients with patellofemoral instability. The aim of orthopaedic surgery should be correction of the underlying pathology with resection of the synovial band and an additional realignment of the patella by recentering of the quadriceps muscle. Considering the underlying pathology good clinical results can be expected.

Osteochondral autologous transplantation (OAT) from the ipsilateral femoral lateral condyle in osteochondritis dissecans (OD) of the talus has shown good clinical results in the past. To further define, indications and limitations of OAT various factors have been discussed which might influence the clinical outcome.

Die Rekonstruktion des medialen patellofemoralen Ligaments (MPFL) wird zunehmend auch zur Behandlung der patellofemoralen Instabilität bei Kindern und Jugendlichen durchgeführt. Aufgrund der offenen Wachstumsfugen setzt eine anatomische MPFL-Rekonstruktion die Kenntnis des femoralen Insertionspunktes des MPFL zur distalen femoralen Wachstumsfuge voraus. Röntgenbilder in 2 Ebenen von 27 Kindern und Jugendlichen mit noch offenen Wachstumsfugen und bekannter patellofemoraler Instabilität wurden ausgewertet. Die Ergebnisse der Studie zeigen, dass die femorale Insertion des MPFL distal der femoralen Wachstumsfuge liegt. Da eine zu proximale femorale Insertion des Transplantats bei der MPFL-Rekonstruktion zu einer ungewollten Spannungszunahme der Knieflexion führen kann, sollten diese Ergebnisse bei der MPFL-Rekonstruktion bei Kindern und Jugendlichen mit offenen Wachstumsfugen berücksichtigt werden. Eigene Ergebnisse dieser Operationstechnik zeigen nach einem Follow-up von mindestens 2 Jahren gute bis sehr gute Ergebnisse ohne Reluxation.

Recurrent lateral patellar dislocation is a common knee injury in the skeletally immature adolescent. In adults, anatomical reconstruction of the medial patellofemoral ligament (MPFL) is recommended, but due to the open physis, operative therapy in children is more challenging. We present a minimal invasive technique for anatomical reconstruction of the MPFL in children respecting the distal femoral physis. This technical note considers the important fact that the femoral insertion is distal to the femoral physis. Since the importance of an anatomical reconstruction respecting the femoral insertion of the ligament has been proven an insertion proximal of the physis has to be strictly avoided.

Melorheostosis is a rare condition of bone and surrounding tissues with different clinical presentations, ranging from clinically inapparent radiographic incidental findings to deformity, resistant chronic pain, swelling, restricted range of motion of the affected joints, leg length discrepancy or even cervical myelopathy. It is characterized by a hyperostosis of long or short bones. It is often associated with cutaneous and vascular changes like naevi, haemangiomas, scleroderma, lymphedema and arteriovenous malformations. Pain is the most common symptom of the condition. The therapy is individual and depends on the clinical manifestation. There are about 350 cases described in the literature until today. The current article presents an actual and most comprehensive review of literature to this rare condition, including 313 cases, focusing on symptomatology, diagnostic steps and the therapeutic options.

The purpose of this study was to analyse true lateral radiographs of children and adolescents to determine the relation of the origin of the MPFL and the distal femoral physis considering the complex anatomy of the physis. The hypothesis was that the femoral insertion of the MPFL is distal to the growth plate.

Metaphyseal chondrodysplasia represents a complex challenge for the orthopaedic surgeon as it potentially affects all long bones of the growing human skeleton.

We report on a 20-year-old female patient with a fracture of the patella after she fell on"black ice" 2 months after medial patellofemoral ligament (MPFL) reconstruction for patellar instability. For reconstruction of the MPFL, a single hamstring tendon graft was passed through the medial intermuscular septum and was fixed to the superomedial pole of the patella. The fracture was reduced by wire cerclage. Intraoperatively it was shown that the fracture line went through the patellar drill hole. No complications occurred during the further postoperative period. The literature contains only a few case reports describing fractures of the patella after MPFL reconstruction without any specific trauma. In this case, an interruption in blood supply with resulting avascular necrosis was suspected as a causal factor.