[Partial replacement of the knee joint with patient-specific instruments and implants (ConforMIS iUni, iDuo)]. / Patientenspezifische Instrumente und Implantate beim Teilgelenkersatz des Kniegelenkes (ConforMIS iUni, iDuo).

Knee arthroplasty is a successful standard procedure in orthopedic surgery; however, approximately 20 % of patients are dissatisfied with the clinical results as they suffer pain and can no longer achieve the presurgery level of activity. According to the literature the reasons are inexact fitting of the prosthesis or too few anatomically formed implants resulting in less physiological kinematics of the knee joint. Reducing the number of dissatisfied patients and the corresponding number of revisions is an important goal considering the increasing need for artificial joints. In this context, patient-specific knee implants are an obvious alternative to conventional implants. For the first time implants are now matched to the individual bone and not vice versa to achieve the best possible individual situation and geometry and more structures (e.g. ligaments and bone) are preserved or only those structures are replaced which were actually destroyed by arthrosis. According to the authors view, this represents an optimal and pioneering addition to conventional implants. Patient-specific implants and the instruments needed for correct alignment and fitting can be manufactured by virtual 3D reconstruction and 3D printing based on computed tomography (CT) scans. The portfolio covers medial as well as lateral unicondylar implants, medial as well as lateral bicompartmental implants (femorotibial and patellofemoral compartments) and cruciate ligament-preserving as well as cruciate ligament-substituting total knee replacements; however, it must be explicitly emphasized that the literature is sparse and no long-term data are available.

[Rehabilitation after periprosthetic fractures]. / Rehabilitation nach periprothetischen Frakturen.

Periprosthetic fractures of the upper and lower extremities not only represent a challenge for surgeons but also for the rehabilitation team. The sometimes multimorbid patients have often undergone several surgical operations and need special planning and cooperation between an interdisciplinary team in order to achieve the best possible functional result and social reintegration. A structured rehabilitation planning after surgical treatment is a prerequisite for the patient to return to life as normal as possible. The aim is always rapid mobilization to achieve independence in activities of daily living. Special attention should be paid to postoperative immobilization and weight bearing.

[Risk of Developing Clinical Symptomatically Postmeniscectomy Bone Marrow Edema]. / Risiko des Auftretens eines klinisch symptomatischen Knochenmarködems nach arthroskopischer Meniskusteilresektion.

BACKGROUND: Bone marrow edema (BME) of the knee is often seen in MRI and has several different underlying pathologies. The correlation between disorders of the knee joint and a BME is not fully understood yet. Persistent or progressive postoperative pain and/or functional impairment after arthroscopic partial meniscectomy is still a common phenomenon in many patients. The aim of this prospective clinical trial was to find a correlation between the typical postoperative disorders and BME in MRI and to identify possible therapeutic consequences. PATIENTS, MATERIAL AND METHODS: 150 consecutive patients with preoperatively diagnosed meniscus defects and without any previous operation and no BME underwent arthroscopic partial meniscectomy. A two- to three-day resting period was established postoperatively. The patients then rapidly returned to full weight bearing. No crutches were used. As a standard analgetic, we used diclofenac 50 mg three times a day for three days. Clinical control and removal of the sutures was performed on day 8 postoperatively. The patients' pain status was controlled by using the IKDC score and the Visual Analogue Scale (VAS) before and six weeks after surgery. Six weeks after the surgical intervention, the patients underwent a standardized physical examination and, if there was ongoing functional impairment or discomfort of the knee, a new MRI was performed. However, if patients showed signs or severe discomfort prior to the end of the six-week observation period an MRI was scheduled earlier. RESULTS: Postoperatively 11 of the 150 patients (7,3 %) developed progressive discomfort with pain during stress and also by night. A postoperative BME in the MRI was seen in all 11 symptomatic patients (100 %). We saw a significant correlation to women older than 70 years (p < 0.05). The VAS score six weeks after arthroscopy was significant reduced in the group without any clinical symptoms (2.63 ± 2.83 after arthroscopy and 4.27 ± 2.36 MW ± SEM before arthroscopy) compared to the group with proven BME (5.09 ± 2.74 before arthroscopy and 5.27 ± 2.57 MW ± SEM after arthroscopy; p < 0.05). The IKDC score was significantly enhanced in the clinical asymptomatic group: 58.1 ± 10.53 in comparison to the patients with proven BME, with 35.32 ± 13.2 MW ± SEM (p < 0.05). CONCLUSION: Patients with clinical symptomatic BME showed a significantly higher VAS score and a significantly lower IKDC score postoperatively. Therefore, in patients with postoperative discomfort, a prompt MRI should be performed and, if a BME is proven, further therapy should be modified.

Therapeutic effect of methotrexate encapsulated in cationic liposomes (EndoMTX) in comparison to free methotrexate in an antigen-induced arthritis study in vivo.

OBJECTIVES: Cationic lipid complexes bind to angiogenic endothelial cells of solid tumours and microvessels of chronic inflammatory tissue. Methotrexate (MTX) is one of the drugs used in the therapy of rheumatoid arthritis (RA); it is applied systemically but can have serious side-effects. The aim of this study was to investigate the impact of MTX encapsulated in cationic liposomes (EndoMTX) in comparison to treatment with free MTX. METHOD: We used an antigen-induced arthritis (AiA) model and investigated the leucocyte- and platelet-endothelial cell interaction in arthritic female C57/Bl6 mice and in healthy controls. The arthritic animals were divided into four different groups receiving either trehalose, free MTX, EndoMTX placebo, or EndoMTX. These parameters and functional capillary density (FCD) were measured and assessed by intravital microscopy (IVM). We controlled clinical parameters such as the knee joint diameter (KJD) throughout the observation period. RESULTS: Animals treated with EndoMTX showed a significant and superior reduction in leucocyte- and platelet-endothelial cell interaction, FCD, and KJD. Free MTX or empty liposomes also showed a reduction in these parameters but not to a significant level. FCD decreased in the EndoMTX group in comparison to using free drugs or empty carrier-like liposomes. CONCLUSIONS: This study demonstrates the advantage of using MTX encapsulated in cationic liposomes in contrast to free and generic MTX, with a higher efficacy in anti-inflammatory and anti-angiogenic abilities. Targeting with cationic liposomes may be a promising treatment option and should be elucidated in further experiments regarding dose reduction and side-effects due to MTX usage.

Development of a new suturing technique for tendon graft preparation: an animal cadaver study.

BACKGROUND: This study should analyze ten different suturing techniques for tendon graft preparation to allow the development of an entirely new suturing technique. METHODS: Extensor tendon grafts of fattening bulls' forelegs were sutured with Ethibond Excel size three (six metric) fibers (Ethicon, Somerville, New York, USA). The tendon/suture complexes were biomechanically tested with a hydraulic testing machine applying traction according to a standardized protocol. The testing was observed to find out why the failure at the maximum traction load occurred. The mean values for the maximum tension and extension stiffness were recorded for each suturing technique. FINDINGS: An entirely new suturing technique was developed based on the observations and biomechanical results. The newly developed suture was also tested and provided a higher traction stability than the other ten techniques that had been evaluated. Compared to the other ten techniques the new technique was ranked 3rd in terms of extension stiffness and reached 10.3 N/mm. INTERPRETATION: The new technique evolved in the course of this study provided promising results. Therefore this study provides initial evidence that this technique could be useful in clinical routine.

[Rehabilitation after sports injuries. Current concepts and data]. / Rehabilitation nach Sportverletzungen. Aktuelle Konzepte und Daten.

Sports injuries and their treatment have become increasingly more important in recent years due to the leisure behaviour of our society. Besides the aspects of acute care and medical treatment there often remains the question of optimal rehabilitative care and return to sports. Overall, the correct early planning of rehabilitation has a great influence on the prognosis of sports injuries and the date of resumption of sporting activities. One of the key aspects to consider is the phase-dependent course of rehabilitation with appropriate therapy focus. A multidisciplinary and interdisciplinary, phase-dependent, individual treatment plan that also complies with the biopsychosocial background of the athlete must be created for this purpose. Increasingly relevant is also the sport psychological support during all phases of rehabilitation, including the use of cognitive behavioral therapy. Before an athlete returns to sports and competition, objectified sport-specific criteria must be met.

Dynamic in vitro analysis of tractile forces of the anterior cruciate ligament (ACL) transplant using patellar and semitendinosus muscle tendon: a cadaver study.

PURPOSE: The presented biomechanical study focused on the in vitro analysis of tractile forces working on the anterior cruciate ligament (ACL) and the ACL transplants, respectively, using a semitendinosus and/or patellar tendon during a passive flexion-extension movement (150-0°). MATERIAL AND METHODS: Overall, 15 fresh frozen human knee joint pairs were examined. At first during arthroscopy, the tibial insertion of the ACL was drilled using a special hollow drill. Thereby, a bone cylinder was exposed at which a dynamometer was attached to enable for direct registration of tractile forces on the ACL via the connection between ACL-dynamometer and computer. The ACL transplant was fixed at the femur using a so-called endo-button, whereas the dynamometer was attached to the tibial end of the ACL transplant. The dynamic part of the examination was performed using the knee kinemator device developed by Plitz and Wirth et al. using different preload. RESULTS: The curves of the tractile forces of the ACL were qualitatively homogeneous with only low force values in the middle flexion position, whereas during maximum flexion and extension the forces increased reaching a maximum in the 0° position. Also, in testing the ACL transplants a force decrease between 0 and 50° flexion was recognized with even greater forces resulting at the 150° position depending on the anterior position of the femoral drill channel for implanting the ACL transplant. The amount of pre-loading showed no influence on the form of the tractile force curve. However, by enhancing the preload to 70 N, the maximal force in the ACL transplant increased significantly. CONCLUSION: The tractile forces assessed within the ACL during passive flexion movements between 10 and 90° were not greater than the forces measured in the ACL transplants. Thus, the clinical consequence is that in the early postoperative phase passive mobilization might be performed in this motion range without putting the ACL transplant at risk for damage.

Simvastatin reduces leucocyte- and platelet-endothelial cell interaction in murine antigen-induced arthritis in vivo.

OBJECTIVES: The use of statins in the prevention and treatment of cardiovascular diseases is well established. Their use as anti-inflammatory and immunomodulatory agents in the treatment of rheumatoid arthritis (RA) has also been investigated, with several clinical and experimental studies indicating an anti-inflammatory effect of statins for RA, but other studies showing no effect or even the opposite. The current study was designed to examine the effect of simvastatin in an in vivo murine model of arthritis using intravital microscopy. METHOD: We assigned four groups (n = 7, female C57Bl6 mice), two with and two without antigen-induced arthritis (AiA), from which one of the non-AiA groups and one of the AiA groups were treated with simvastatin 40 mg/kg i.p. daily for 14 consecutive days after induction of arthritis. Platelet- and leucocyte-endothelial cell interaction was assessed by measurement of rolling and adherent fluorescence-labelled platelets and leucocytes, functional capillary density (FCD) was evaluated, and knee joint diameter was determined as a clinical parameter. RESULTS: In arthritic mice treated with simvastatin, a significant reduction in platelet- and leucocyte-endothelial cell interaction was observed in comparison to arthritic mice treated with vehicle. In addition, a significant reduction in FCD was seen in arthritic mice treated with simvastatin, along with a reduction in knee joint swelling of the AiA mice. CONCLUSIONS: Treatment of AiA mice with simvastatin showed significant reductions in platelet- and leucocyte-endothelial cell interactions, in FCD, and in the swelling of the knee joint. These results support the hypothesis of the anti-inflammatory effects of statins in the treatment of RA.

Biological activity and migration of wear particles in the knee joint: an in vivo comparison of six different polyethylene materials.

Wear of polyethylene causes loosening of joint prostheses because of the particle mediated activity of the host tissue. It was hypothesized that conventional and crosslinked polyethylene particles lead to similar biological effects around the knee joint in vivo as well as to a similar particle distribution in the surrounding tissues. To verify these hypotheses, particle suspensions of six different polyethylene materials were injected into knee joints of Balb/C mice and intravital microscopic, histological and immunohistochemical evaluations were done after 1 week. Whereas the biological effects on the synovial layer and the subchondral bone of femur and tibia were similar for all the polyethylenes, two crosslinked materials showed an elevated cytokine expression in the articular cartilage. Furthermore, the distribution of particles around the joint was dependent on the injected polyethylene material. Those crosslinked particles, which remained mainly in the joint space, showed an increased expression of TNF-alpha in articular cartilage. The data of this study support the use of crosslinked polyethylene in total knee arthroplasty. In contrast, the presence of certain crosslinked wear particles in the joint space can lead to an elevated inflammatory reaction in the remaining cartilage, which challenges the potential use of those crosslinked polyethylenes for unicondylar knee prostheses.

[Approach to painful hip resurfacing]. / Vorgehen bei schmerzhafter Kappenprothese.

Hip resurfacing in young patients has been increasingly performed within the last decade. In comparison to standard total hip arthroplasty the failure rate remains high. Age and implant size have a significant effect on the risk of revision for primary total resurfacing and the risk of revision increases with increasing age. At 7 years the cumulative revision rate for patients is 5% and females have more than twice the cumulative revision rate as males. Even in hip resurfacing arthroplasty which has been performed in a perfect manner, a certain percentage of patients suffer from persistent pain for various reasons, such as neck fracture, iliopsoas tendinopathy, metal hypersensitivity, such as aseptic lymphocytic vasculitis associated lesions (ALVAL) and aseptic loosening. Diagnostic work-up of the painful hip resurfacing is challenging even for experienced surgeons. Recommendations for the diagnostic procedure are described.

[Rehabilitation and sport following total hip replacement]. / Rehabilitation und Sport nach Hüfttotalendoprothese.

The number of total hip replacement (THR) surgeries has increased significantly over the last few years and patients undergoing surgery are of decreasing age. In consequence the question of the influencing factors for the survival of artificial hip joints becomes more and more urgent. The expected survival time of an implant is nowadays 15-20 years and it seems that factors for a shorter lifetime are female gender, overweight, younger age and certain indications which led to surgery, such as rheumatoid arthritis or fractures. In the early phase of rehabilitation, measures against dislocation including training of the abductor muscles are most important. Starting rehabilitation programs early after surgery has positive effects on outcome, especially when strengthening programs are included. There are different opinions concerning the question how the lifetime of a THR is influenced by sports activities. However, it seems to have been demonstrated that suitable sports activities have a positive effect and do not necessarily correlate with higher loosening rates after THR. In general, high-impact sports should be avoided. Recommended activities are cycling, swimming, aquajogging, hiking, rowing and dancing.

[Uncemented arthroplasty of the hip]. / Zementfreie Endoprothetik des Hüftgelenks.

Prognosis of cemented total hip replacement seems to be excellent for elderly patients. In younger age the outcome is less favourable and early revision is more common. Thus, different concepts with better prognosis and preservation of bone stock for possible revisions were needed. After more than 30 years of application with excellent short-term and long-term results, uncemented total hip arthroplasty is nowadays generally regarded as the standard procedure for younger patients. New bone-preserving implants, such as surface replacement or short-stemmed femoral shaft prostheses, have been introduced especially for younger patients. Some of these new procedures are still under development, and the long-term results of new implant concepts have to be evaluated over the next decades. Regarding recently published scientific studies an overview about non-cemented total hip arthroplasty is given and current concepts and developments are presented.

Timing of cervical spine stabilisation and outcome in patients with rheumatoid arthritis.

One complication of rheumatoid arthritis (RA) is the involvement of the cervical spine (CS). Although prophylactic stabilisation is recommended, the timing at which this should occur is poorly defined. The aim of our study was to evaluate the course of neurological symptoms in terms of the timing of surgery. A total of 34 patients with RA and CS involvement were surgically stabilised. These patients were classified using the Ranawat (RW) score both preoperatively and at an average of 54 months post-operatively. For each patient, the presence of atlantoaxial and subaxial subluxation as well as vertical migration of the odontoid was recorded. The anterior atlantodental interval was also assessed pre- and post-operatively. Improvement was obtained in 20 patients, the clinical situation remained unchanged in three patients and three patients manifested disease progression. In terms of the RW score, the 16 patients with pre-operative RW grades I-II showed no deterioration at the post-operative follow-up, with 13 of these patients showing an improvement; the 12 patients with pre-operative RW grades IIIA-IIIB did not show any improvement of neurological symptoms at follow-up, although seven of these patients subjectively assessed the symptoms to be less severe after surgery; three other patients showed a worsening of symptoms. Our results suggest that preventive stabilisation of CS in RA leads to acceptable results, although the complications of the surgery are obvious. However, early operative treatment may delay the detrimental course of cervical myelopathy in RA.

Selective inhibition of platelets by the GPIIb/IIIa receptor antagonist Tirofiban reduces leukocyte-endothelial cell interaction in murine antigen-induced arthritis.

OBJECTIVE: Inflammation is associated with the invasion of leukocytes into affected tissues and with the up-regulation of platelet activation and adhesion. Assuming that leukocyte accumulation is linked to platelet aggregation, the aim of our study was to examine the effects of selective platelet inhibition by the glycoprotein (GP) IIb/IIIa receptor antagonist Tirofiban on the leukocyte-endothelial cell interaction. MATERIAL AND METHODS: We used the model of antigen-induced arthritis (AiA) to induce inflammatory changes in the synovial microcirculation. Ex vivo labelled platelets and in vivo fluorescence-labelled leukocytes were visualized by intravital microscopy (IVM). C57/Bl6 mice were allocated to four groups; two control groups with saline or Tirofiban and two groups with AiA that also received either saline or Tirofiban (0.5 microg/g BW) intravenously. RESULTS: There was no significant change in platelet- or leukocyte- endothelial cell interaction in the endothelium in healthy control animals. In contrast, after selective inhibition of platelets, the platelet- and leukocyte-endothelial cell interaction was significantly reduced in arthritic mice and reached the level of the healthy control groups. CONCLUSION: Selective platelet inhibition by Tirofiban resulted in reduced leukocyte-endothelial cell interactions in AiA. Consequently, platelets contribute to leukocyte adhesion in AiA via GPIIb/IIIa and therefore platelet inhibition could become an additional therapy option in chronic arthritic disease.

In vivo interactions of platelets and leucocytes with the endothelium in murine antigen-induced arthritis: the role of P-selectin.

OBJECTIVE: Platelets are thought to participate in the pathogenesis of chronic inflammatory diseases such as rheumatoid arthritis (RA). We showed recently an in vivo increase in platelet-endothelial cell interactions in mice with antigen-induced arthritis (AiA). The underlying mechanisms are not yet clear. The aim of this study was to investigate the impact of P-selectin in AiA by means of intravital fluorescence microscopy (IVM). METHODS: C57/Bl6 mice and P-selectin-deficient mice were divided into four groups (n = 7; control/AiA per strain). The extent of AiA was assessed by measuring knee joint swelling and by histological scoring. Rolling and adherent fluorescence-labelled platelets and leucocytes were investigated by IVM. RESULTS: In arthritic P-selectin-deficient mice (rolling: 0.05+/-0.01; adherent: 130+/-20 mm(-2)), compared to arthritic C57/Bl6 mice (rolling: 0.20+/-0.04; adherent: 1910+/-200 mm(-2)), platelet interaction was significantly reduced (p<0.05) and reached the level of both control groups without AiA. In addition, interaction of leucocytes in P-selectin-deficient arthritic animals (rolling: 0.12+/-0.06; adherent: 387+/-37 mm(-2)) was significantly decreased in comparison to arthritic C57/Bl6 animals (rolling: 0.21+/-0.06; adherent: 1492+/-284 mm(-2); p<0.05). Swelling of the knee joint and histological scoring were reduced in arthritic P-selectin-deficient mice compared to arthritic C57/Bl6 mice. CONCLUSION: We have demonstrated for the first time in vivo a significant decrease in the interaction of platelets and leucocytes with the endothelium in P-selectin-deficient mice with AiA and a reduction in clinical and histological symptoms of arthritis. These findings suggest that leucocyte-endothelial cell interactions depend at least partially on platelet P-selectin and therefore platelets may be responsible for the leucocyte tissue damage in AiA.

Platelet P-selectin is significantly involved in leukocyte-endothelial cell interaction in murine antigen-induced arthritis.

There is growing evidence that platelets play an important role in the development and maintenance of rheumatoid arthritis. Activation and adherence of platelets in the synovial microcirculation might be in part responsible for endothelial damage and activation of leukocytes. Recent findings show a direct influence of P-selectin on platelet- and leukocyte-endothelial cell interaction in mice with Antigen-induced Arthritis (AiA). P-selectin is only expressed by platelets and endothelial cells, not by leukocytes. Therefore, the aim of the present study was to investigate the differential influence of platelet and endothelial P-selectin on the extent of inflammation in AiA. AiA was induced in wild-type mice and in P-selectin-deficient mice from the same genetic background (four groups: each n = 7). Intravital fluorescence microscopy (IVM) was used to visualize platelets and leukocytes in the synovial microcirculation at day 8 after AiA. Platelets from either strain were fluorescence-labelled ex vivo and transferred into either strain. We were able to demonstrate a significant decrease of platelet- and leukocyte-endothelial cell interaction in P-selectin-deficient mice with AiA in comparison to wild-type mice with AiA. When wild-type platelets were donated into P-selectin-deficient AiA recipients, the leukocyte-endothelial cell interaction was significantly increased compared to the group consisting of P-selectin-deficient recipient and donor mice. These are the first in vivo results showing that the P-selectin stored in platelets is at least partly responsible for the leukocyte-endothelial cell interaction and the resulting tissue damage in AiA. In the future, a suppression of platelet P-selectin could potentially become a treatment option for reducing the effects of rheumatoid arthritis.

Endothelial iNOS versus platelet iNOS: responsibility for the platelet/leukocyte endothelial cell interaction in murine antigen induced arthritis in vivo.

OBJECTIVE: Since an increase of platelet-endothelial cell interactions has been observed in mice with Antigen- induced-Arthritis (AiA) as well as an increase of NO expression, the aim of our study was to investigate in vivo the influence of NO, especially the platelet and endothelial inducible NO Synthase, on the platelet- and leukocyte endothelial cell interaction. MATERIAL AND METHODS: C57/Bl6 mice and iNOS deficient mice were disposed in 6 groups (each=7). After induction of AiA, rolling and adherent fluorescence labelled platelets and leukocytes were investigated by intravital microscopy (IVM) on day 8 after AiA. Rank SUM Test and ANOVA on ranks have been performed regarding the data. RESULTS: All arthritic mice presented an increase in platelet and leukocyte interaction with the endothelium compared to control groups. The arthritic iNOS deficient mice showed a more intense interaction of platelets and leukocytes with the endothelium in comparison with the wild-type arthritic mice. The group using arthritic wild-type recipient and iNOS deficient donor mice showed an increase in cell-interactions, leading to an endothelial effect, compared to the group using iNOS deficient arthritic recipient and wild-type donor mice. CONCLUSION: The IVM data lead to an anti-inflammatory effect of NO, since NO followed an increase in platelet- and leukocyte- endothelial cell interaction in iNOS deficient mice with AiA. In addition, we have shown for the first time in vivo that platelet NO produced by iNOS seems to have a minor influence on the leukocyte induced tissue damage in contrast to endothelial iNOS. Therefore, selective platelet inhibition would not interfere with the protective effect of NO.

Aggressive scapular chondroblastoma with secondary metastasis--a case report and review of literature.

Chondroblastoma is a benign bone tumor, accounting for approximately one percent of all benign bone tumors. It mostly occurs in typical locations such as long bones. Malignant transformation including metastasis has been described in only a few cases. Therefore, we report a unique case of chondroblastoma with tumor manifestation in the 7th decade of life, location of the tumor in the scapula and occurrence of metastasis in the soft tissue of the mandible branch. Due to aggravation of the clinical course, a scapula en bloc resection was performed. The differential diagnosis is discussed and the current literature concerning malignant transformation of chondroblastoma is reviewed.

Retrograde intramedullary nailing in tibiotalocalcaneal arthrodesis: a short-term, prospective study.

In this prospective study, tibiotalocalcaneal arthrodesis was performed in 29 patients with a retrograde femur nail (Interlocking Compression Nail; Stryker Trauma, Schönkirchen, Germany) inserted through a plantar approach. Patients were evaluated by a standardized follow-up examination using the American Foot and Ankle Society ankle-hindfoot scale and the main criteria of the short-form health survey (36 items). Special emphasis was placed on surgical approach, bony consolidation, and postoperative quality of life. Solid fusion was achieved in 90% of the patients after a mean follow-up of 25 months. Twenty-two patients (76%) showed primary bone healing after an average of 5.2 months; a delayed union was observed in 7 patients. In 79% of the patients, pain was reduced effectively and quality of life substantially improved with the intramedullary nail arthrodesis. The average ankle-hindfoot score improved from 46 (range, 41-53) to 71 (range, 49-83) points. Complications occurred in 6 patients (21%), including 2 deep infections, 3 nonunions, and 1 case of postoperative flexion deformity. The authors found retrograde intramedullary nailing in tibiotalocalcaneal arthrodesis to be an effective technique in obtaining solid fusion, an effective relief from pain, and an improvement of quality of life.

[Diagnosis specific differences in knee joint geometry. A challenge for the correct axial implantation of long stems in total knee arthroplasty]. / Diagnosespezifische Unterschiede der Kniegelenkgeometrie. Herausforderung bei der achsgerechten Implantation langstieliger Kniegelenkendoprothesensysteme.

BACKGROUND: Arthrotic deformities with changes in knee geometry can produce difficulties in implanting long stem knee prosthesis systems using intramedullary alignment. They can result in incorrect lower limb axis and prosthesis positioning. The aim of the presented study was to measure knee geometry in patients with varus and valgus gonarthrosis in order to define diagnosis related differences. METHODS: A total of 75 patients with indication for total knee arthroplasty were divided in two groups using the weight bearing lower limb axis: patients with varus gonarthrosis (n=43) and with valgus gonarthrosis (n=32). Angles and extensions, important for knee prosthesis implantation, were measured, digitalized and analyzed. The results were investigated for diagnosis specific differences. RESULTS: After regulation of the measured extension in mean femur/tibia lengths, significant diagnosis specific differences were found: femur condyles were widened towards pathologic weight bearing (P<0.044), and the mechanical tibia axis of the varus gonarthrosis group is transferred to the lateral side (P<0.046) and in projection over the lateral internal cortical substance. CONCLUSION: The significant differences in deformed arthrotic knees indicate that for an optimal postoperative result the use of standard implants is not always sufficient. Modular knee prosthesis systems can provide adequately for individual demands.