Conservative versus tailored surgical treatment in patients with first time lateral patella dislocation: a randomized-controlled trial.

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 .

Different Kinematics of Knees with Varus and Valgus Deformities.

Few data exist of kinematics of knees with varus and valgus deformities combined with osteoarthritis. The purpose of this study was to reveal different (1) tibiofemoral kinematics, (2) medial and lateral gaps, and (3) condylar liftoff of osteoarthritic knees with either varus or valgus deformity before and after total knee arthroplasty (TKA). For this purpose, 40 patients for TKA were included in this study, 23 knees with varus deformity and 17 knees with valgus deformity. All patients underwent computer navigation, and kinematics was assessed before making any cuts or releases and after implantation. Osteoarthritic knees with valgus deformity showed a significant difference in tibia rotation relative to the femur with flexion before and after TKA, whereas knees with varus deformity did not. Knees with a valgus deformity showed femoral external rotation in extension and femoral internal rotation in flexion, whereas knees with a varus deformity revealed femoral internal rotation in extension and femoral external rotation in flexion. In both groups, gaps increased after TKA. Condylar liftoff was not observed in the varus deformity group after TKA. In the valgus deformity group, condylar liftoff was detected after TKA at knee flexion of 50 degrees and more. This study revealed significant differences in tibiofemoral kinematics between osteoarthritic knees with a varus or valgus deformity before and after TKA. Valgus deformities showed a paradoxic movement pattern. These in vivo intraoperative results need to be confirmed using fluoroscopic or radiographic three-dimensional matching before and after TKA.

[Joint replacement in the elderly]. / Gelenkersatz des älteren Menschen.

Special characteristics must be taken into consideration for replacement arthroplasty in the elderly. The indications, preoperative preparation, postoperative care, implant selection, intraoperative technique, as well as clinical results reveal sometimes substantial differences compared to younger patients. Based on these findings it is important to individualize the approach to patient therapy, especially due to distinct differences between chronological and biological age in the elderly, in association with the level of activity and expectations on the new joint. All types of implants, each with implant-specific characteristics that must be taken into consideration, are available independent of the age of the patient. In summary, attributes such as stability and pain-free mobility have to be given priority in the elderly.

What is the optimal valgus pre-set for intramedullary femoral alignment rods in total knee arthroplasty?

PURPOSE: In total knee arthroplasty (TKA), intramedullary guides are often used for aligning the distal femoral cutting block. Because of the highly varying angles between the mechanical axis and the anatomical femoral axis (AMA), different valgus pre-sets have been recommended. The present study investigated the optimal valgus pre-set (measuring the AMA in long-leg radiographs or at 5°, 6°, 7° or 8° valgus) to align the cutting block perpendicularly to the mechanical axis. METHODS: The AMA was preoperatively measured in weight-bearing long-leg radiographs. After alignment of the cutting block by means of an intramedullary rod, deviation of the block from the mechanical femoral axis was measured with a pinless navigation device. The true AMA (tAMA) was calculated by adding the valgus pre-set of the alignment rod to the deviation measured with the navigation device. Mean deviations between the tAMA and (a) the AMA measured by the surgeon, (b) the AMA calculated with the computer software, (c) 5°, (d) 6°, (e) 7° and (f) 8° valgus pre-sets were measured for each patient. The lowest mean differences were determined. RESULTS: The 40 knees measured showed a mean tAMA of 7.2° valgus (1.7 SD) (range 4°-11.5°). The following mean differences and 95 % limits of agreement were calculated: 2.2 (-1.2, 5.5) to the tAMA for the 5° valgus pre-set, 1.2 (-2.2, 4.5) for 6°, 0.2 (-3.2, 3.5) for 7° and -0.8 (-4.2, 2.5) for 8°. AMA measurements by the surgeon and with the digital medical planning software yielded mean differences of 0.6 (-3.1, 4.3) and 0.4 (-4.1, 4.8), respectively. CONCLUSION: In the present setting, the best mean distal femoral cutting block alignment perpendicular to the mechanical femoral axis could be achieved with a valgus pre-set of 7° and not by measuring the AMA. Nevertheless, we recommend conducting weight-bearing radiographs of the entire leg prior to TKA for easy detection of any anatomical varieties, old fractures, long stems of total hip arthroplasties or cement. However, surgeons must be aware that exact coronal component alignment can only be achieved by navigational devices. LEVEL OF EVIDENCE: Diagnostic study, Level II.

[Patella navigation in computer-assisted TKA : Intraoperative measurement of patellar kinematics. Video article]. / Patellanavigation bei computerassistierter Knie-TEP-Implantation : Eine Technik zur intraoperativen Messung der Patellakinematik. Videobeitrag.

INTRODUCTION: Patellofemoral maltracking is a relevant problem after total knee arthroplasty (TKA). Patella navigation is a tool that allows real time monitoring of patella tracking. MATERIAL: This video contribution demonstrates the technique of patellofemoral navigation and a possible consequence of intraoperative monitoring. A higher postoperative lateral tilt is addressed with a widening of the lateral retinaculum in a particular manner. CONCLUSION: In selected cases of patellofemoral problems, patella navigation is a helpful tool to evaluate patellofemoral tracking intraoperatively. Modifications of implant position and soft tissue measurements can then prevent postoperative patellofemoral maltracking.

[Course of pain after operative orthopedic interventions: Characterization exemplified by total knee arthroplasty]. / Schmerzverlauf nach operativer orthopädischer Intervention : Charakterisierung am Beispiel der Knieendoprothetik.

BACKGROUND: The number of cases of orthopedic surgery is still increasing and postoperative pain management is of great importance for the patients. Therefore, in this study factors influencing the pain and the developement of pain in general in the first 7 days after total knee arthroplasty were examined. MATERIAL AND METHODS: A total of 28 patients were included in this prospectively designed trial and underwent total knee arthroplasty with psoas compartment and sciatic nerve regional anesthesia and additionally propofol sedation. Postoperative pain scores were documented using a numerical rating scale (NRS) and anthropometric data and perioperative parameters were correlated with the postoperative pain score. RESULTS: Evaluation of the pain values per interval showed that the maximum and the mean postoperative pain levels decreased up to day 4 after surgery and then increased. No significant effects of the analyzed parameters age, body mass index (BMI), duration of surgery and catheter indwelling time could be found. Female patients had significantly more pain than males in this collective. CONCLUSION: The results show that there were no factors which have a significant influence on the degree of postoperative pain. Female patients suffered from more pain than males. There was an increase in pain after postoperative day 4 which might be the effect of more extensive mobilization and reduced effects of regional anesthesia. It is important that pain is treated in the early postoperative period.

Difference in periprosthetic acetabular bone mineral density: Prior total hip arthroplasty: Osteonecrosis of the femoral head versus primary osteoarthritis.

BACKGROUND: Total hip arthroplasty (THA) could be associated with a higher failure rate in patients after osteonecrosis of the femoral head (ONFH) compared to a patient population with primary osteoarthritis prior THA, especially regarding the acetabular component. One major reason could be the compromised acetabular bone quality. Therefore, we performed a retrospective case matched study to assess: 1) Is there a difference in periprosthetic bone mineral density between patients with an ONFH prior THA and controls? 2) Do patients with an ONFH prior THA have a lower bone mineral density compared to controls? 3) Which region in the periprosthetic bone stock is more likely to present differences in periprosthetic bone mineral density between both groups? HYPOTHESIS: We hypothesized that there is a poorer bone mineral density (BMD) in the periacetabular bone stock in patients with an ONFH prior THA compared to controls receiving a THA due to primary osteoarthritis. PATIENTS AND METHODS: We compared the BMD of 50 patients with ONFH to 50 controls with primary osteoarthritis prior THA using the same implant in mean 5 years after surgery by means of dual energy X-ray absorptiometry (DXA). We analysed 3 acetabular ROIs according to DeLee and Charnley in a modified measurement technique. RESULTS: In ROI 3, representing acetabulum's upper aspect, statistically significant lower BMD values for the ONFH group could be found (P < 0.05). No difference was found for the modified ROIs 1 and 2 (respectively medial and lower acetabulum). DISCUSSION: The results indicate a poorer periacetabular BMD in patients with ONFH prior THA, which might be responsible for premature loosening of the acetabular cup in THA. Due to a lack of literature, further clinical investigations are required to confirm our results. LEVEL OF EVIDENCE: III: retrospective case-control study.

[Clinical examination of the hip joint in adults]. / Klinische Untersuchung des Hüftgelenkes des Erwachsenen.

Complaints in the region of the hips and pelvis are often difficult to classify. This is due to the fact that pain projection and overlapping can occur; therefore, the complete region of the lumbar spine, pelvis and hips must be considered as a single entity in which alterations can result in radiation throughout the whole region. There are many different anatomical structures within the pelvic region so that the function of various muscle components can be impaired and cause pathological alterations to positional relationships of bony structures or even alterations to other soft tissues, such as ligaments, tendons and labra. In terms of differential diagnostics the groin must be seen as the weak point of the peritoneum and vascular system and taken into consideration. Therefore, a detailed and targeted medical history, functional testing and specific examinations and tests are necessary to narrow down the pathology in question and reach a definitive diagnosis. Orthopedic surgeons must know which conspicuous features can lead to which problems and which anatomical structures are likely to be affected by irritation. The results of the clinical examination are the basis for targeted imaging diagnostics and subsequent therapy.

[Bone defect adjusted strategy in revision arthroplasty of the hip : Wich implant in wich situation? Innovations and approved methods]. / Defektadaptierte Rekonstruktionsstrategien in der Hüftrevisionsendoprothetik : Welches Implantat in welcher Situation? Innovationen und Bewährtes.

BACKGROUND: Revision total hip arthroplasty is of rising importance, with 35,000 procedures a year in Germany. OBJECTIVES: Primary stability of the revision implant, reconstruction of the anatomical hip center, reconstruction of bone stock, and permanent secondary integration are the main priorities. METHODS: Current literature and examples from our own experience are presented. RESULTS AND CONCLUSIONS: Novel developments from basic research and industrial partners extend the possibilities for treating affected patients. For an integrated therapy concept in implant selection criteria, such as situation and structure of the defect, combination with any remaining implants, causes of loosening and failure, implant allergy, and patient-specific parameters should be taken into consideration.

The validity of a novel radiological method for measuring femoral stem version on anteroposterior radiographs of the hip after total hip arthroplasty.

Femoral stem version has a major influence on impingement and early post-operative stability after total hip arthroplasty (THA). The main objective of this study was to evaluate the validity of a novel radiological method for measuring stem version. Anteroposterior (AP) radiographs and three-dimensional CT scans were obtained for 115 patients (female/male 63/72, mean age 62.5 years (50 to 75)) who had undergone minimally invasive, cementless THA. Stem version was calculated from the AP hip radiograph by rotation-based change in the projected prosthetic neck-shaft (NSA*) angle using the mathematical formula ST = arcos [tan (NSA*) / tan (135)]. We used two independent observers who repeated the analysis after a six-week interval. Radiological measurements were compared with 3D-CT measurements by an independent, blinded external institute. We found a mean difference of 1.2° (sd 6.2) between radiological and 3D-CT measurements of stem version. The correlation between the mean radiological and 3D-CT stem torsion was r = 0.88 (p < 0.001). The intra- (intraclass correlation coefficient ≥ 0.94) and inter-observer agreement (mean concordance correlation coefficient = 0.87) for the radiological measurements were excellent. We found that femoral tilt was associated with the mean radiological measurement error (r = 0.22, p = 0.02). The projected neck-shaft angle is a reliable method for measuring stem version on AP radiographs of the hip after a THA. However, a highly standardised radiological technique is required for its precise measurement.

[Prevention of periprosthetic joint infections : Not evidence-based strategies]. / Vermeidung periprothetischer Infektionen : Nicht evidenzbasierte Maßnahmen.

BACKGROUND: Surgical site infections are the most common nosocomial infections in orthopedic surgery. Strategies to prevent these infections are of enormous relevance. OBJECTIVES: Evidence-based procedures such as hand disinfection, prophylactic antibiotic application, hair removal with electric clippers, or preoperative treatment of Staphyloccus aureus are listed in national and international guidelines. Beside these measures, several scientifically not confirmed methods, e.g., the administration of antibiotic prophylaxis for several days or the usage of helmets during surgery, are still practiced. These measures are not evidence-based and should not be performed anymore. CONCLUSION: Only the consequent implementation of evidence-based procedures can help prevent surgical site infections.

[Clinical examination of the hip joint in adults]. / Klinische Untersuchung des Hüftgelenkes des Erwachsenen.

Complaints in the region of the hips and pelvis are often difficult to classify. This is due to the fact that pain projection and overlapping can occur; therefore, the complete region of the lumbar spine, pelvis and hips must be considered as a single entity in which alterations can result in radiation throughout the whole region. There are many different anatomical structures within the pelvic region so that the function of various muscle components can be impaired and cause pathological alterations to positional relationships of bony structures or even alterations to other soft tissues, such as ligaments, tendons and labra. In terms of differential diagnostics the groin must be seen as the weak point of the peritoneum and vascular system and taken into consideration. Therefore, a detailed and targeted medical history, functional testing and specific examinations and tests are necessary to narrow down the pathology in question and reach a definitive diagnosis. Orthopedic surgeons must know which conspicuous features can lead to which problems and which anatomical structures are likely to be affected by irritation. The results of the clinical examination are the basis for targeted imaging diagnostics and subsequent therapy.

[Minimally invasive treatment of depression fractures of the tibial plateau using balloon repositioning and tibioplasty: video article]. / Die minimal-invasive Versorgung von Tibiakopfimpressionsfrakturen mit Hilfe der Ballonreposition und Tibioplastie : Videobeitrag.

BACKGROUND: The aim of surgical treatment of fractures of the tibial head is an exact reconstruction of the joint plateau. For this purpose the method of balloon tibioplasty is now available in selected cases. This article and the accompanying video material illustrate the minimally invasive technique of tibioplasty using an actual example of patient treatment. METHODS: This technique offers gentle reduction by slow expansion of the balloon. The large balloon surface ensures that more bone can be lifted carefully at once in order to achieve the anatomical position. The positioning of the balloon requires surgical precision. Balloon reduction creates a well-defined bone cavity of known volume and is stabilized using calcium phosphate cement. Possible risks are cement leakage and secondary loss of reduction. RESULTS: Thus far, results are promising, but long-term results are still lacking. Therefore, the indication should be made carefully and differentiated.

[Influence of intraoperative noise protection on postoperative pain: demonstrated exemplified by total knee arthroplasty]. / Einfluss der intraoperativen Schallprotektion auf postoperative Schmerzen : Dargestellt am Beispiel der Knieendoprothetik.

BACKGROUND: It is known that implied memory of intraoperative noise influences postoperative pain. The aim of this study was to evaluate the influence of different intraoperative noise protection methods during total knee arthroplasty on postoperative pain scores. MATERIAL AND METHODS: A total of 83 patients were included in this prospectively designed, double-blind trial and underwent total knee arthroplasty with psoas compartment and sciatic nerve regional anesthesia and additionally propofol sedation. After randomization patients were assigned either to the noise protection group, the music group or the control group. Postoperative pain scores (VAS) were evaluated in each group. RESULTS: In the three different time intervals evaluated there were no significant differences between the groups. Also the pain maxima for each postoperative day showed no significant difference but there was a slight trend to the advantage of the music group. CONCLUSION: Even though there were no significant effects of music or noise protection on postoperative pain scores, it can be concluded, as has been done by many other authors that music should be used in the perioperative setting for general patient comfort.

[Radiological findings, evaluation and treatment of patellofemoral pain after total knee arthroplasty]. / Radiologische Diagnostik, Beurteilung und Behandlung des patellofemoralen Schmerzes nach primärer Knieendoprothetik.

Total knee arthroplasty (TKA) is one of the most successful operative procedures over the last decades in orthopedic surgery; however, some patients suffer from pain, limited range of motion, instability, infections or other complications postoperatively. Patellofemoral pain (PFP) in particular is a common problem after TKA and often necessitates revision surgery. Mainly increasing and localized contact pressure and patella maltracking are held responsible for PFP but the reasons vary. Diagnostics and therapy of PFP is not easy to manage and should be treated following a clinical pathway. The authors suggest that patients with PFP should be categorized after basic diagnostic measures according to the suspected diagnosis: (1) tendinosis, (2) mechanical reasons, (3) intra-articular non-mechanical reasons and (4) neurogenic/psychiatric reasons. Efficient application of special diagnostic measures and further therapy is facilitated by this classification.

Comparison of UHMWPE particles in synovial fluid and tissues from failed THA.

The size and morphology of ultra high molecular weight polyethylene (UHMWPE) wear particles isolated from synovial fluid and periprosthetic tissues from three failed total hip arthroplasties were evaluated. Hip capsule, femoral canal tissue, and synovial fluid were collected at the time of revision surgery. The polyethylene wear particles were isolated and then imaged using a scanning electron microscope. The size and morphology of the particles were quantified using an image analysis protocol. Five shape descriptors were defined for each particle: equivalent circle diameter (ECD, a measure of size having units of length), aspect ratio (AR), elongation (E), roundness (R), and form factor (FF). The size and shape of the polyethylene particles differed depending on the source. Femoral tissue particles had the lowest equivalent circle diameter (0.697 +/- 0.009 mm), aspect ratio (1.577 +/- 0.016), and elongation (1.912 +/- 0.030), but the highest values for roundness (0.715 +/- 0.005) and form factor (0.874 +/- 0.003). Hip capsule particles had the highest equivalent circle diameter (0.914 +/- 0.019 mm), aspect ratio (1.764 +/- 0.025), and elongation (2.488 +/- 0.053), but the lowest values for roundness (0.642 +/- 0.006) and form factor (0.803 +/- 0.005). The size and shape descriptors for synovial fluid particles (equivalent circle diameter: 0.763 +/- 0.012 mm; aspect ratio: 1.700 +/- 0.029; elongation: 2.212 +/- 0.054; roundness: 0.681 +/- 0.006; and form factor: 0.841 +/- 0.004) were intermediate among the femoral tissue and hip capsule particles. These data suggest that larger particles may become lodged in the hip capsule, while smaller particles may migrate to more distant tissues and subsequently cause aseptic loosening and osteolysis.