Under-correction of preoperative varus alignment does not lead to a difference in in-vivo bone loading in 3D-SPECT/CT compared to neutral alignment.

BACKGROUND: The aim was to investigate the correlation of bone tracer uptake (BTU) in SPECT/CT and changes in coronal knee alignment after total knee arthroplasty (TKA). We questioned if undercorrection of preoperative varus alignment leads to a difference in BTU compared to neutral alignment. METHODS: Consecutive 66 patients who received SPECT/CT before and after TKA were retrospectively included. Adjusted mechanical alignment was the alignment target. The alignment of the knee was measured on 3D-CT by selecting standardized landmarks. Maximum (mean ± SD) and relative BTU (ratio to the reference) were recorded using a previously validated localization scheme (p < 0.05). RESULTS: In the native group, 20 knees were aligned (30.3%) in valgus (HKA > 181.5°), 12 (18.2%) in neutral (178.5°-181.5°) and 34 (51.5%) in varus (HKA < 178°). Overall TKA changed the alignment towards neutral. 48.5% remained in the same groups, whereas 50% of native valgus and 33% of varus knees changed to neutral after TKA. In native varus alignment mean BTU was significantly higher in some medial tibial and femoral regions (fem1ia (p = 0.010), fem1ip (p = 0.002), tib1a.mid (p = 0.005), tib1a.tray (p = 0.000), tib1p.tray (p = 0.000)); in native valgus alignment mean BTU was higher in the corresponding lateral tibial and femoral regions (fem2ip (p = 0.001), tib2a.tray (p = 0.011), tib2p.tray (p = 0.002)). After TKA, a significant decrease in femoral and tibial BTU (femoral preoperative BTU 1.64 +/-0.69; femoral postoperative BTU 0.95 +/-0.42; p = 0.000// tibial preoperative BTU 1.65 +/- 0.93; tibial postoperative BTU 1.16 +/- 0.48; p = 0.000) and an increase in patellar BTU was observed (p = 0.025). Native varus alignment correlated with a higher medial BTU decrease medially. Undercorrection of preoperative varus alignment showed no higher BTU after TKA. CONCLUSION: Preoperative varus alignment correlated with a higher decrease in BTU in specific femoral and tibial medial regions. Preoperative valgus alignment correlated with a higher decrease in the corresponding lateral regions. Undercorrection of preoperative varus alignment did not lead to higher bone loading reflected by BTU after TKA.

Increased patellar bone tracer uptake in preoperative SPECT/CT before medial opening high tibial osteotomy correlates with inferior clinical outcome.

PURPOSE: The purpose of this study was to investigate whether specific bone tracer uptake (BTU) patterns on preoperative SPECT/CT could predict which patients with varus alignment and medial overload would particularly benefit from medial opening-wedge high tibial osteotomy (MOWHTO). It was the hypothesis that an increased preoperative BTU relative to the reference BTU of the femur on SPECT/CT in the lateral and patellar compartments of the knee are predictive factors for inferior clinical outcome and that the clinical outcome correlates with the extent of alignment correction. METHODS: Twenty-three knees from 22 patients who underwent MOWHTO for medial compartment overload were investigated preoperatively using Tc-99m-SPECT/CT. BTU was quantified and localised to specific joint areas according to a previously validated scheme. Pre- and postoperative mechanical alignment was measured. Clinical outcome was assessed at a median of 24 months (range 11-30) after MOWHTO by collecting the WOMAC score. RESULTS: Significant correlations between BTU in the patellar area and the total WOMAC score and its subcategories pain and stiffness were found. Thus, BTU in the 1sPat area (superior lateral patellar compartment) correlated with total WOMAC (rho = 0.43, p = 0.04), pain subcategory (rho = 0.43, p = 0.04), and stiffness subcategory (rho = 0.59, p = 0.003). No significant correlations were found between alignment correction, age, gender and WOMAC. CONCLUSION: This study highlights the role of preoperative SPECT in modern knee surgery to obtain information about the loading pattern on different compartments of the knee. Despite the limited number of participants, the present study shows that a preoperative SPECT/CT scan can help the treating surgeons to identify patients who may be at risk of inferior clinical outcome if an MOWHTO is considered, as an elevated BTU in the patellar region on preoperative SPECT/CT appears to be a potential risk factor for postoperative pain and stiffness. LEVEL OF EVIDENCE: Level III.

"Recommendations for periprosthetic joint infections (PJI) prevention: the European Knee Associates (EKA)-International Committee American Association of Hip and Knee Surgeons (AAHKS)-Arthroplasty Society in Asia (ASIA) survey of members".

PURPOSE: Periprosthetic joint infections (PJIs) represent a devastating consequence of total joint arthroplasty. The European Knee Associates (EKA), the American Association of Hip and Knee Surgeons (AAHKS) International Committee, and the Arthroplasty Society in Asia (ASIA) board members were interested in quantifying differences in arthroplasty surgeons' use of various PJI prevention measures to provide clinical recommendations to reduce PJI incidence. METHODS: A prospective Microsoft Forms online survey was distributed among EKA, AAHKS International Committee, and ASIA members and their affiliated arthroplasty surgeons. The survey consisted of 20 single and multiple response questions focused on PJI prevention strategies at three perioperative periods: preoperatively, intraoperatively, and postoperatively. RESULTS: Three hundred and ninety-four arthroplasty surgeons from 6 different continents completed the survey. Preoperative: (A) PJI Risk Stratification: 40.6% routinely set thresholds (e.g., BMI, HgbA1C) to be met to qualify for surgery, 36.5% only review past medical history; 9.1% use machine learning to personalize PJI risk; (B) BMI limit: 36% no limit; 15.4% BMI < 35; 30.9% BMI < 40; 17.2% BMI < 45; (C) Nutritional status: 55.3% do not screen; among those who screen their patients (44.7%), albumin is the single most used marker (86.3%); (D) Hyperglycemia/Diabetes: 83.3% check this comorbidity; 88.1% use HgbA1C as single best screening test; (E) MRSA nasal colonization: 63.7% do not test; 28.9% test all patients; 7.4% test selectively. Intraoperative: (A) Antibiotic prophylaxis in high-risk patients: 43.4% use single antibiotic for 24 h; 21.3% use double antibiotic for 24 h; 14.2% use single/double antibiotic for 7 days postoperatively; (B) Skin-cleansing: 68.7% at home (45.6% chlorhexidine sponge; 11.9% clippers); (C) Intraoperative skin disinfection: 46.9% single chlorhexidine; 25% double chlorhexidine-povidone-iodine;15.4% single povidone-iodine; (D) Tranexamic acid (TXA) to reduce bleeding/SSI: 96% yes (51% double IV dose, 35.2% single IV dose, 23.6% intra-articular injection); (E) Surgical suction drain: 52% do not use drains; 19.7% use a drain < 24 h; (F) Intra-articular lavage: 64.9% use only saline; 28.1% use dilute povidone-iodine; (G) Antibiotic local delivery to prevent PJI: 82.4% use antibiotic-added cement. Postoperative: (A) Routine monitoring of PJI serologic markers: 42% only in symptomatic patients; 34.2% do not; 20.8% in all patients; (B) Serologic markers to rule in/out PJI: 95.9% CRP; 71% SEDRATE; 60.6% WBC; (C) Synovial fluid test to rule in/out PJI: 79.6% culture/sensitivity; 69.5% WBC count; 31.4% CRP. CONCLUSIONS: This survey demonstrated that notable differences still exist in the application of PJI preventive measures across different geographic areas: Optimizing the patient preoperatively and applying multimodal intraoperative strategies represent newer, clinically relevant steps in the effort to reduce the burden of PJI. More uniform guidelines still need to be produced from international scientific societies in order facilitate a more comprehensive approach to this devastating complication. LEVEL OF EVIDENCE: IV.

[Recommendations for unicondylar knee replacement in the course of time : A current inventory]. / Empfehlungen zur unikondylären Schlittenendoprothetik im Wandel der Zeit : Eine aktuelle Bestandsaufnahme.

BACKGROUND: A higher patient satisfaction stands in contrast to higher revision rates of unicondylar knee joint endoprosthetics (UKE) compared to total knee joint endoprosthetics (TKE). Furthermore, old "dogmas" regarding indications and contraindications persist, which is still reflected in the significantly different case numbers. AIM: The aim of this article is to provide an overview of the current literature regarding 1. indication and contraindication (BMI, age, sport, arthrosis of other compartments, ligament status) and 2. the "eternal rival" fixed or mobile bearing for UKE. RESULTS: The choice of the right patient remains essential, even if all the old "dogmas" of contraindications have been relativized or even outdated. Arthroses of the contralateral (in medial UKE correspondingly lateral) compartment and advanced arthroses of the lateral patella facet remain the only persistent contraindications. In contrast, a high BMI, age, chondrocalcinosis, medial patella facet and a defective (but particularly functionally stable) ACL are not contraindications; however, severe obesity is responsible for a significantly higher complication rate and probably a higher rate of loosening. Rather, the experience and thus the number of UKEs of the individual surgeon is decisive for the outcome, to which the discussion about mobile or fixed inlays must also be completely subordinated. CONCLUSION: The indications for UKE can, therefore, be extended with a clear conscience on the basis of literature, and the current 1:10 UKE:TKE ratio in Germany can be shifted significantly.

Resuming elective hip and knee arthroplasty after the first phase of the SARS-CoV-2 pandemic: the European Hip Society and European Knee Associates recommendations.

PURPOSE: The Covid-19 pandemic has disrupted health care systems all over the world. Elective surgical procedures have been postponed and/or cancelled. Consensus is, therefore, required related to the factors that need to be in place before elective surgery, including hip and knee replacement surgery, which is restarted. Entirely new pathways and protocols need to be worked out. METHODS: A panel of experts from the European Hip Society and European Knee Association have agreed to a consensus statement on how to reintroduce elective arthroplasty surgery safely. The recommendations are based on the best available evidence and have been validated in a separate survey. RESULTS: The guidelines are based on five themes: modification and/or reorganisation of hospital wards. Restrictions on orthopaedic wards and in operation suite(s). Additional disinfection of the environment. The role of ultra-clean operation theatres. Personal protective equipment enhancement. CONCLUSION: Apart from the following national and local guidance, protocols need to be put in place in the patient pathway for primary arthroplasty to allow for a safe return.

It is not 'business as usual' for orthopaedic surgeons in May 2020- the Austrian-German-Swiss experience.

PURPOSE: To document the status-quo of orthopaedic health-care services as the COVID-19 pandemic recedes, and to determine the rate of resumption of orthopaedic surgery in the German-speaking countries in May 2020. METHODS: A prospective online survey was sent out to 4234 surgeons of the AGA - Society of Arthroscopy and Joint-Surgery (Gesellschaft für Arthroskopie und Gelenkchirurgie, AGA). The survey was created using SurveyMonkey software and consisted of 23 questions relating to the reduction of orthopaedic services at the participating centres and the impact that the pandemic is having on each surgeon. RESULTS: A total of 890 orthopaedic surgeons responded to the online survey. Approximately 90% of them experienced a reduction in their surgical caseload and patient contact. 38.7% stated that their institutions returned to providing diagnostic arthroscopies. 54.5% reported that they went back to performing anterior cruciate ligament reconstructions (ACLR), 62.6% were performing arthroscopic meniscus procedures, and 55.8% had resumed performing shoulder arthroscopy. Only 31.9% of the surgeons were able to perform elective total joint arthroplasty. 60% of the participants stated that they had suffered substantial financial loss due to the pandemic. CONCLUSION: A gradual resumption of orthopaedic health-care services was observed in May 2020. Typical orthopaedic surgical procedures like ACLR, shoulder arthroscopy and elective total joint arthroplasty were reported to be currently performed by 54%, 56% and 32% of surgeons, respectively. Despite signs of improvement, it appears that there is a prolonged curtailment of orthopaedic health-care at present in the middle of Europe.

Recommendations for resuming elective hip and knee arthroplasty in the setting of the SARS-CoV-2 pandemic: the European Hip Society and European Knee Associates Survey of Members.

PURPOSE: The COVID-19 pandemic has disrupted the health care system around the entire globe. A consensus is needed about resuming total hip and knee procedures. The European Hip Society (EHS) and the European Knee Association (EKA) formed a panel of experts that have produced a consensus statement on how the safe re-introduction of elective hip and knee arthroplasty should be undertaken. METHODS: A prospective online survey was done among members of EHS and EKA. The survey consisted of 27 questions. It includes basic information on demographics and details the participant's agreement with each recommendation. The participant could choose among three options (agree, disagree, abstain). Recommendations focussed on pre-operative, peri-operative, and post-operative handling of patients and precautions. RESULTS: A total of 681 arthroplasty surgeons participated in the survey, with 479 fully completing the survey. The participants were from 44 countries and 6 continents. Apart from adhering to National and Local Guidelines, the recommendations concerned how to make elective arthroplasty safe for patients and staff. CONCLUSION: The survey has shown good-to-excellent agreement of the participants with regards to the statements made in the recommendations for the safe return to elective arthroplasty following the first wave of the COVID-19 pandemic.

Disruption of joint arthroplasty services in Europe during the COVID-19 pandemic: an online survey within the European Hip Society (EHS) and the European Knee Associates (EKA).

PURPOSE: The aim of the present study was to evaluate the impact of the coronavirus (COVID-19) pandemic on joint arthroplasty service in Europe by conducting an online survey of arthroplasty surgeons. METHODS: The survey was conducted in the European Hip Society (EHS) and the European Knee Associates (EKA). The survey consisted of 20 questions (single, multiple choice, ranked). Four topics were addressed: (1) origin and surgical experience of the participant (four questions); (2) potential disruption of arthroplasty surgeries (12 questions); (3) influence of the COVID-19 pandemic on the particular arthroplasty surgeon (four questions); (4) a matrix provided 14 different arthroplasty surgeries and the participant was asked to state whether dedicated surgery was stopped, delayed or cancelled. RESULTS: Two-hundred and seventy-two surgeons (217 EHS, 55 EKA) from 40 different countries participated. Of the respondents, 25.7% stated that all surgeries were cancelled in their departments, while 68.4% responded that elective inpatient procedures were no longer being performed. With regard to the specific surgical procedures, nearly all primary TJA were cancelled (92.6%) as well as aseptic revisions (94.7%). In most hospitals, periprosthetic fractures (87.2%), hip arthroplasty for femoral neck fractures and septic revisions for acute infections (75.8%) were still being performed. CONCLUSION: During the current 2020 COVID-19 pandemic, we are experiencing a near-total shutdown of TJA. A massive cutback was observed for primary TJA and revision TJA, even in massively failed TJA with collapse, dislocation, component failure or imminent dislocation. Only life-threatening pathologies like periprosthetic fractures and acute septic TJA are currently undergoing surgical treatment. LEVEL OF EVIDENCE: V.

Massive cutback in orthopaedic healthcare services due to the COVID-19 pandemic.

PURPOSE: Due to the lack of evidence, it was the aim of the study to investigate current possible cutbacks in orthopaedic healthcare due to the coronavirus disease 2019 pandemic (COVID-19). METHODS: An online survey was performed of orthopaedic surgeons in the German-speaking Arthroscopy Society (Gesellschaft für Arthroskopie und Gelenkchirurgie, AGA). The survey consisted of 20 questions concerning four topics: four questions addressed the origin and surgical experience of the participant, 12 questions dealt with potential cutbacks in orthopaedic healthcare and 4 questions addressed the influence of the pandemic on the particular surgeon. RESULTS: Of 4234 contacted orthopaedic surgeons, 1399 responded. Regarding arthroscopic procedures between 10 and 30% of the participants stated that these were still being performed-with actual percentages depending on the specific joint and procedure. Only 6.2% of the participants stated that elective total joint arthroplasty was still being performed at their centre. In addition, physical rehabilitation and surgeons' postoperative follow-ups were severely affected. CONCLUSION: Orthopaedic healthcare services in Austria, Germany, and Switzerland are suffering a drastic cutback due to COVID-19. A drastic reduction in arthroscopic procedures like rotator cuff repair and cruciate ligament reconstruction and an almost total shutdown of elective total joint arthroplasty were reported. Long-term consequences cannot be predicted yet. The described disruption in orthopaedic healthcare services has to be viewed as historic. LEVEL OF EVIDENCE: V.

Analysis of the Attune tibial tray backside: A comparative retrieval study.

OBJECTIVES: The Attune total knee arthroplasty (TKA) has been used in over 600 000 patients worldwide. Registry data show good clinical outcome; however, concerns over the cement-tibial interface have been reported. We used retrieval analysis to give further insight into this controversial topic. METHODS: We examined 12 titanium (Ti) PFC Sigma implants, eight cobalt-chromium (CoCr) PFC Sigma implants, eight cobalt-chromium PFC Sigma rotating platform (RP) implants, and 11 Attune implants. We used a peer-reviewed digital imaging method to quantify the amount of cement attached to the backside of each tibial tray. We then measured: 1) the size of tibial tray thickness, tray projections, peripheral lips, and undercuts; and 2) surface roughness (Ra) on the backside and keel of the trays. Statistical analyses were performed to investigate differences between the two designs. RESULTS: There was no evidence of cement attachment on any of the 11 Attune trays examined. There were significant differences between Ti and CoCr PFC Sigma implants and Attune designs (p < 0.05); however, there was no significant difference between CoCr PFC Sigma RP and Attune designs (p > 0.05). There were significant differences in the design features between the investigated designs (p < 0.05). CONCLUSION: The majority of the earliest PFC Sigma designs showed evidence of cement, while all of the retrieved Attune trays and the majority of the RP PFC trays in this study had no cement attached. This may be attributable to the design differences of these implants, in particular in relation to the cement pockets. Our results may help explain a controversial aspect related to cement attachment in a recently introduced TKA design.Cite this article: A. Cerquiglini, J. Henckel, H. Hothi, P. Allen, J. Lewis, A. Eskelinen, J. Skinner, M. T. Hirschmann, A. J. Hart. Analysis of the Attune tibial tray backside: A comparative retrieval study. Bone Joint Res 2019;8:136-145. DOI: 10.1302/2046-3758.83.BJJ-2018-0102.R2.

[Bone void fillers in osteotomies : If, when, and which type?] / Füllung des Osteotomiespalts : Ob, wann und womit?

Medial opening wedge high tibial osteotomy (HTO) is an established procedure for treating medial osteoarthritis of the knee. In order to achieve the desired amount of correction, the osteotomy gap is opened, which creates a bone void in the medial aspect of the proximal tibia. The resulting bone void can either be left alone or be addressed by interposing a variety of different bone void fillers. Autologous and allogenic fillers can be distinguished from synthetic materials. Up to now, few studies have dealt with the usefulness and necessity for bone void fillers in HTO. The following article provides an overview on the currently used bone void fillers, their specific advantages and disadvantages and their influence on clinical and radiographic outcome after HTO.

The biomechanical strength of a hardware-free femoral press-fit method for ACL bone-tendon-bone graft fixation.

PURPOSE: The purpose was to investigate graft slippage and ultimate load to failure of a femoral press-fit fixation technique for anterior cruciate ligament (ACL) reconstruction. METHODS: Nine fresh-frozen knees were used. Standardized harvesting of the B-PT-B graft was performed. The femora were cemented into steel rods, and a tunnel was drilled outside-in into the native ACL footprint and expanded using a manual mill bit. The femoral bone block was fixed press-fit. To pull the free end of the graft, it was fixed to a mechanical testing machine using a deep-freezing technique. A motion capture system was used to assess three-dimensional micro-motion. After preconditioning of the graft, 1000 cycles of tensile loading were applied. Finally, an ultimate load to failure test was performed. Graft slippage in mm ultimate load to failure as well as type of failure was noted. RESULTS: In six of the nine measured specimens, a typical pattern of graft slippage was observed during cyclic loading. For technical reasons, the results of three knees had to be discarded. 78.6 % of total graft slippage occurred in the first 100 cycles. Once the block had settled, graft slippage converged to zero, highlighting the importance of initial preconditioning of the graft in the clinical setting. Graft slippage after 1000 cycles varied around 3.4 ± 3.2 mm (R = 1.3-9.8 mm) between the specimens. Ultimate loading (n = 9) revealed two characteristic patterns of failure. In four knees, the tendon ruptured, while in five knees the bone block was pulled out of the femoral tunnel. The median ultimate load to failure was 852 N (R = 448-1349 N). CONCLUSION: The implant-free femoral press-fit fixation provided adequate primary stability with ultimate load to failure pull forces at least equal to published results for interference screws; hence, its clinical application is shown to be safe.

The Genovese grading scale is not reliable for MR assessment of collagen meniscus implants.

BACKGROUND: The purpose of the study was to evaluate the intra- and inter-observer reliabilities of the Genovese grading on MRI in patients after collagen meniscus substitution. METHODS: 84 MRI images of 74 consecutive patients who underwent partial meniscus substitution using collagen meniscus implant (CMI) were assessed. MRIs were evaluated using the Genovese grading system. Furthermore, meniscal extrusion was assessed. Two observers performed the grading twice, blinded to each other and to the previous results, with a six weeks interval. The inter- and intra-observer reliabilities were assessed using kappa and weighted kappa values. RESULTS: The criterion "morphology/size" showed a weighted kappa value inter-observer reliability of 0.069 (rater 1)/0.352 (rater 2) and intra-observer reliability of 0.170 (1st rating)/0.582 (2nd rating). The criterion "signal intensity" showed a weighted kappa value inter-observer reliability of 0.175/0.284 and intra-observer reliability of 0.294/0.458. The criterion "cartilage lesions" showed a kappa value inter-observer reliability of 0.091/0.525 and intra-observer reliability of 0.409/0.413. The criterion "bone marrow edema" showed a kappa value inter-observer reliability of 0.667/0.808 and intra-observer reliability of 0.702/0.715. The criterion "cartilage lesions" showed a kappa value inter-observer reliability of 0.091/0.525 and intra-observer reliability of 0.409/0.413. Regarding meniscal extrusion kappa values for the inter-observer reliability were 0.625/0.940 and 0.625/0.889 for intra-observer reliability. CONCLUSIONS: Three of the four Genovese grading items showed only slight to moderate inter- and intra-observer reliabilities in evaluating CMI on MRI. Hence, such grading results need to be considered with all due care. Only the criteria "bone marrow edema" and "meniscal extrusion" showed a good agreement for both inter- and intra-observer reliabilities.

Symptomatic versus asymptomatic knees after bilateral total knee arthroplasty: what is the difference in SPECT/CT?

PURPOSE: The primary purpose of this retrospective study was to evaluate the differences of bone tracer uptake (BTU) in symptomatic and asymptomatic knees after bilateral total knee arthroplasty (TKA) and identify typical BTU patterns with regards to TKA component position and alignment. METHODS: A consecutive number of 37 patients after bilateral TKA were retrospectively included. The knees were grouped into symptomatic (group A) and asymptomatic (group B) knees. All patients underwent 99m-Tc-HDP-SPECT/CT. Coronal, rotational, and sagittal TKA component position was analysed in 3D reconstructed CT. BTU was anatomically localised and quantified using a validated standardized localization scheme. Maximum BTU values for each area were recorded and normalized values calculated. Signed log-rank test, chi-square test, paired t-tests, and Pearson correlations were used (p <0.05). RESULTS: Symptomatic TKAs were significantly more flexed and had a tendency to be more internally rotated when compared to asymptomatic ones (p < 0.05). In all regions, the mean BTU in asymptomatic knees was lower than in symptomatic knees. In both groups the highest mean BTU was found around the tibial stem (symptomatic 7.30; asymptomatic 6.30, p = 0.061) and at the tip of the tibial stem (symptomatic 5.49; asymptomatic 4.74, p = 0.062). Superior patellar regions showed higher BTU than inferior regions. The highest patellar BTU was found in the superior medial patella (symptomatic 4.99; asymptomatic 3.98, p = 0.048). The lowest BTU was found in the posterior femoral regions (flatsp, flatip, fmedsp, fmedip) (Table 3). Tibial and patellar areas showed twice as high mean BTUs than femoral areas (Fig. 3). A significant correlation of TKA component position and BTU was demonstrated. CONCLUSIONS: Distribution and intensity of BTU in SPECT/CT depends on TKA component position and alignment. In addition, typical BTU patterns in symptomatic and asymptomatic knees were identified. A profound knowledge of BTU pattern, TKA component position, and alignment helps to identify pathologies in patients after TKA. CLINICAL EVIDENCE: Diagnostic study, level II.

Temporary hemiepiphysiodesis of the distal medial femur: MPFL in danger.

INTRODUCTION: Temporary hemiepiphysiodesis (TH) with plate fixation is a well-accepted and common treatment for correcting leg malalignment in skeletally immature patients. The purpose of this study was to investigate any soft tissue damage caused during TH at the distal medial femur with a plate and two screws. We hypothesized that correct plate placement can affect the integrity of the medial stabilizing structures of the knee, especially the medial patellofemoral ligament (MPFL), the medial collateral ligament (MCL) or result in arthrotomy of the knee joint itself. MATERIALS AND METHODS: In eight cadaveric knees of five adult humans a TH was performed with a plate and two cancellous screws at the distal medial femur using a standardized surgical technique. Subsequently the medial capsular and ligamentous structures were systematically exposed and assessed. Capsular and synovial tissue was also inspected for impingement by the plate or screws. RESULTS: In all knees the MPFL was present. In two specimens the MPFL was intact and the plate was lying over the dorsal part of the MPFL close to the MCL. The MPFL was completely cut in two cases in the central part of the ligament. In four cases the MPFL was partially dissected or perforated by a screw and fixed to the femur by the plate. The MCL was intact and not impinged by the implant in any case. In total four of eight knees the capsule was transected or perforated by a screw or by a part of the plate, resulting in intraarticular implant placement. CONCLUSIONS: Standard plate placement during TH on the distal medial femur frequently leads to damage to the MPFL, impingement of the MPFL, the capsular and synovial tissues or exposure of the knee joint.

[Non-dislocated osteoporotic insufficiency fracture of the medial femoral neck. SPECT/CT makes the diagnostic difference]. / Undislozierte osteoporotische Insuffizienzfraktur des medialen Schenkelhalses. SPECT/CT macht den diagnostischen Unterschied.

Osteoporotic fragility fractures of the femoral neck are the most common type of fractures in the elderly and are associated with a high mortality. Most frequently these fractures are due to falls but spontaneous onset has also been described. In these patients the insufficient quantity and quality of the osteoporotic bone finally leads to the development of a fragility or insufficiency fracture. In some cases of nondisplaced insufficiency fractures the diagnosis cannot be established by conventional radiographs alone and magnetic resonance imaging (MRI), single proton emission computed tomography (SPECT) or SPECT/CT are considered as diagnostic adjuncts. We report the case of an 83-year-old patient who had complained of ongoing weight-bearing pelvic pain for over 6 months. There was no history of trauma. The clinical conventional radiographs as well as CT could not elucidate the cause of the problems. To differentiate between lumbal and hip pain a SPECT/CT was performed and the diagnosis of a medial femoral neck insufficiency fracture was established. In the delayed phase a band-like increased tracer uptake within the medial femoral neck was observed. The SPECT/CT procedure is a promising diagnostic alternative for geriatric patients and can be particularly recommended in cases of persistent unclear pelvic or lumbar spine pain in the elderly.