Introduction

SPECT/CT might be a promising diagnostic modality in patients with painful total knee arthroplasty. It was the purpose of our study to introduce a novel standardised SPECT/CT algorithm for assessing patients with painful primary total knee arthroplasty and to evaluate its clinical applicability and inter- and intra-observer variation and reliability.

Background: Traumatic dislocations of the knee are uncommon (< 1% of all dislocations), but they account to the most serious ligament and soft tissue injuries of the knee. Diagnosis and treatment of the dislocated knee present a major challenge to the orthopaedic surgeon. The purpose of our retrospective study was to critically analyze the clinical outcome of all traumatic knee dislocations treated operatively between 1996 and 2006 in our institution.

Methods: Retrospective clinical case series study of all patients treated for traumatic knee dislocation (m: w=12:4; mean age 31 yrs, range 17–63 yrs) from 1998–2006.

The mechanism of injury was a traffic accident (n=7), a sport trauma (n=8) and slip and fall (n=1). The charts of all patients were analyzed.

The clinical outcome was assessed by personal telephone interview by a modified SSK questionnaire by Insall. Surgery was performed by one team of surgeons 2–89 days after trauma.

Mean and range were reported for continuous variables and relative and absolute frequencies vor categorial variables. Data were analyzed using Stata version 8. The level of significance was defined as p< 0.05.

Results: The injury pattern is reported below:

15 anterior cruciate ligament (ACL) lesions (11x ACL reconstruction), 15 posterior cruciate ligament (PCL) lesions (9x refixation, 3x reconstruction), 13 medial collateral ligament (MCL) lesions (8x reconstruction), 6 medial posterior collateral ligament (MPCL) lesions (4x reconstruction), 4 lateral collateral ligament (LCL) lesions (1x reconstruction), 3 popliteal muscle injuries (2x reconstruction), 5 medial meniscal lesions, 10 lateral meniscal lesions (9x suture, 1x partial meniscectomy), 3 femoral fractures, 1 proximal tibial fracture.

Conclusions: Even though in a orthopaedic clinic specialized in the treatment of knee injuries traumatic knee dislocations remain a demanding therapeutic challenge. A highly specialized, customized and sophisticated treatment strategy of a experienced team of surgeons, nurses and physiotherapists is mandatory for acheivement of optimal functional and subjective outcome.

We have explored indentation-type scanning force microscopy (IT SFM) that allows for a direct, quantitative inspection of cartilage morphology and biomechanical properties from the millimeter to the nanometer scale ex vivo, and ultimately, in situ (Stolz et al., 2004). Here we present three examples of using IT SFM where morphological and biomechanical changes could only be spotted at the sub-micrometer scale:

We employed IT SFM for quality control of engineered cartilage cultured under various conditions. These measurements harbor the prospect to optimize and yield engineered cartilage that exhibits long-term mechanical stability, functionality and biocompatibility for joint arthroplasty.

Accordingly, the stiffness of the aging cartilage increased concomitant with a decrease of its glycosaminoclycan (GAG) moiety. Frequently, aging articular cartilage takes a pathological turn called osteoarthritis (OA), which usually ends with a complete disappearance of the articular cartilage layer. Towards an early detection of OA in the human body, we inspected the morphological and biomechanical status of articular cartilage biopsies representing different grades of OA according to the ‘Outerbridge scale’. Most significantly, the early changes (grades 0 to 2) were only detectable at the nanometer scale, but not at the micrometer or millimeter scale. Based on such ex vivo indentation testing, we started to move from the bench to the patient, aiming to directly inspect the quality of human articular knee cartilage by an arthroscopic SFM (Imer et al., 2006). The arthroscopic SFM might just be the beginning of a new generation of nano tools designed for endoscopic or catheter-based interventions of other parts of the body. For such prophylactic interventions to eventually being tolerated by the patient, not only have these to be ambulant and minimally invasive, but they will require a change of paradigm vis-à-vis the patient, namely to undergo an invasive procedure without feeling sick – indeed a big challenge for nanomedicine and managed health care!

Introduction: Cementless implantation of acetabular cups is the standard procedure of choice nowadays. We report on a new hemispheric acetabular socket with Trabecular-Metal-Surface made out of tantalum for cement-less implantation that meets all the requirements that are considered essential for direct osseointegration of cementless implants like porosity, surface roughness and biocompatibility. This multi-center study reports on the surgical technique and the early 5-year clinical results with this implant at three orthopaedic institutions.

Material und Methods: Since 1998 a total of 186 of these cups were implanted in three orthopaedic departments. All patients were followed-up prospectively. 32 implantations were performed with computer-assisted navigation, all others were done manually. In 18 cases the ceramic-on-ceramic articulation was used, all the other patients received Ceramic-on-HDPE as the standard articulation. The cup was combined with different stems including cementless Zweymueller stem, the cementless SBG stem and the cemented Weber-Stuehmer stem. A standard lateral or antero-lateral approach was used in all the patients. The first 112 consecutively patients with a minimum follow-up of 5 years were evaluated.

Results: Postoperative Harris-Hip-Score could be improved to median 92. The positions of all the cups implanted with computer navigation were within a +/−3 range with respect to the intended target whereas manual implantation yielded differences of up to 10. Radiographically all cups showed full osseointegration after one year in all zones. Initial gaps in zone II in 7 cases were filled-up completely. There was no migration and no radiolucency. Two well-fixed cups had to be removed because of infection around the stem. We encountered two dislocations within the first six weeks in patients with Ceramic-on-HDPE-articulation. Both of them could be successfully treated by closed reduction. There were no clinical or radiographic signs of aseptic loosening. No other complications like deep vein thrombosis, hematoma or wound infection did occur.

Conclusion: The new tantalum surface showed excellent osseointegration in all patients. Even in those cases of infection the cup was well-fixed. Due to its hemispheric surface it can be positioned quite easily and shows excellent primary stability. This new poro-coating surface ensures firm fixation of the implant and promises an unprecedented long-term stability.

Aims: To clarify whether joint loading after meniscus repair causes increased pressure on the femoral condyle and is responsible for early cartilage damage. Methods: In sixteen human cadaver knees a bucket handle tear was created at the posterior horn of the medial and lateral meniscus. The lesion was repaired using two biodegradable implants (either Stingerª, Arrow¨, Dartª or Meniscal Screwª) on each occasion. Loading was compared to intact menisci and menisci after suture repair using 2/0 Ethibond. The specimens were mounted into specially designed jigs, taking all degree of freedom of the knee joint into account, and þxed to a material testing machine (Bionix 858 MTS). Constant loading of 350 N was performed during knee motion of 0¡Ð90¡ of ßexion. The meniscofemoral pressure was measured using the Tekscansystem. All þxation techniques were tested þve times. Results: Increased joint loading at the posterior horn occurred with increased ßexion angle of 0¡, 30¡, 60¡ and 90¡ of knee ßexion in the medial and lateral compartment (p< 0.05). No signiþcant increase in joint loading was noticed after meniscus repair with biodegradable implants. Conclusions: Biodegradable implants do not cause higher meniscofemoral joint loading due to meniscus implants in the posterior horn and resulting cartilage damage at the femoral condyle is unlikely.

Introduction

There are numerous arthroscopic techniques available for the treatment of femorotibial osteoarthritis. Advances in arthroscopic technology have made arthroscopic treatment a widespread accepted treatment. Short-term pain relief after arthroscopic treatment in degenerative conditions of the knee has been well established, however this this not the case for the long-term results.

One of the reasons why arthroscopic procedures are well accepted is the favorable risk–benefit ratio, when compared to more invasive procedures like realignment osteotomies, unicompartmental or even total knee arthroplasty (15,16,17,18,19,21,26) Very often the arthroscopic procedure is offered to the patient as a temporizing or “time gaining” measures (11,23,24). However their efficacy is often unequal. Almost no prospective controlled studies are yet available. Arthroscopic mosaicplasty techniques as well as arthroscopically assisted autologous chondrocyte transplantations are – in this context – not regarded upon as treatment options for the osteoarthritic knee and are therefore described elsewhere.

Arthroscopic techniques in knee osteoarthritis

- (Partial) Meniscectomy

Results published in peer-reviewed journals

- (Partial) Meniscectomy: Results more dependent on the status of the knee joint, than on the age of the patient (15,17). For the treatment of chondrocalcinosis there are controversing results: Many authors found actually chondrocalcinosis to be an adverse prognostic factor (6,8,19). Meniscectomy is not always a benign procedure (5)