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Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IX | Pages 76 - 76
1 Mar 2012
Iranpour F Konala P Cobb JP Friederich N Hirschmann MT
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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.

Methods

A novel SPECT/CT localisation scheme, which consists of 9 tibial, 9 femoral and 4 patellar regions on standardised transverse, coronal, and sagittal slices was introduced. It was assessed in 18 consecutive patients with painful knees after total knee arthroplasty. The localisation and level of the tracer uptake on SPECT/CT were noted using a color coded 10 steps graded scale (0-100). The inter and intra-observer reliability were assessed. The femoral and tibial prosthetic component position was assessed in the CT images after 3D reconstruction and aligning them to standardised frames of reference. The average root mean square difference±standard deviations and ranges of these measured angles are presented along with the intraclass correlation coefficients for inter- and intraobserver reliability.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 9 - 9
1 Mar 2009
Hirschmann M Rychen T Lorez L Friederich N
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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.

One angiography was performed. No vascular lesion was observed.

The follow up rate was 93% complete. The mean follow up time was 58 months (range 35–156).

83% of patients were able to return to work without any impairment. 62% of patients returned to the same level of sport activity. 54% of patients were absolutely painfree.

Based on a modified SSK score by Insall a mean of 182 points (range 129–200) on a scale with maximum 200 points could be noted.

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.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 171 - 172
1 Mar 2009
Stolz M Raiteri R Gottardi R Daniels D Friederich N Imer R Staufer U Fässler R Aebi U
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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.

For a more rational understanding of cartilage biology and pathology, we have recently investigated the articular cartilage of mice lacking the β1-integrin in chondrocytes. The β1-integrin gene knock-out mice differed only in stiffness when measured at the nanometer scale, i.e., exhibiting a softer extracellular matrix compared to their wild-type controls.

We inspected the changes of aging articular cartilage by employing a mouse model.

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!


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_I | Pages 52 - 52
1 Mar 2006
Widmer K Bereiter H Ackermann J Friederich N
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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.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_III | Pages 344 - 344
1 Mar 2004
Becker R Wolf C Neumann H Friederich N Nebelung W Wirz D
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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.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 352 - 352
1 Nov 2002
Friederich N König U Petsinis G
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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

- Chondral Shaving

- Removal of osteophytes

- Removal of loose bodies

- Synovectomy

- Subchondral drilling techniques (Pridie)

- Abrasive chondroplasty

- Microfracturing techniques

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)

- Chondral Shaving: This technique of chondral debridement, removal of cartilaginous flaps etc. has become very accepted with the advent of motorized instruments. Positive short-term results have been published, on the long-term this treatment however still fails to have proven efficacy (1,2,3,9,10,11). In some studies simple needle lavage, as performed by many rheumatologists, proved as effective as the arthroscopic method (4,8,17).

- Removal of osteophytes: Several studies show a benefit, when mechanically disturbing osteophytes are removed (3,16)

- Removal of loose bodies: One of the most rewarding arthroscopic techniques. Only free bodies in the anterior compartment of the knee are responsible for blocking, catching and/or pain (6,9)

- Synovectomy: At the first moment making sense – removing inflamed synovia may be of benefit to the patient, we caution. Even when utilizing some of the newer radio-frequency ablation devices (Arthro-care® etc), important postoperative hemarthrosis may occur and may cause longstanding postoperative problems after knee arthroscopy (18,19)

- Subchondral drilling: Originally described by Pridie in 1959, this technique of “subchondral stimulation” creating and stimulating re-growth of type I collagen layers has been adapted to arthroscopic techniques (22)

- Abrasive chondroplasty: This rather aggressive technique, introduced by Lanny Johnson in 1986, has a decreased popularity, since almost nobody but the creator reported good mid- to long-.term results (7,12,13,25)

- Microfracturing: A similar technique to the Pridie drilling technique, however avoiding any heat damage due to the fact that the perforations of the subchondral plate are performed by “ice-picks”. Its advocates report good to excellent results on the short-term (20,27,28)