Assessment of pelvic tilt in anteroposterior radiographs by means of tilt ratios

INTRODUCTION

In anteposterior (AP) radiographs, cup position in total hip arthroplasty and acetabular anatomy in hip-preserving surgery are highly influenced by pelvic tilt. The sagittal rotation of the anterior pelvic plane is an important measurement of pelvic tilt during hip surgery. Thus, correct evaluation of cup position and acetabular parameters requires the assessment of pelvic tilt in AP radiographs.

METHODS

Changes in pelvic tilt inversely change the height of the lesser pelvis and the obturator foramen in AP radiographs. Tilt ratios were calculated by means of these two parameters in simulated radiographs for ten male and ten female pelvises in defined tilt positions. A tilt formula obtained by exponential regression analysis was evaluated by two blinded investigators by means of 14 simulated AP radiographs of the pelvis with pelvic tilts ranging from + 15° to - 15°.

RESULTS

No differences were found between male and female tilt ratios for each 5° step of simulated pelvic tilt. Pelvic tilt and tilt ratios correlated exponentially. Using the tilt formula, the two blinded investigators were able to assess pelvic tilt with high conformity, a mean relative error of + 0.4° (SD ± 4.6°), and a mean absolute error of 3.9° (SD ± 2.3°). Neutral pelvic tilt is indicated by a tilt ratio of 0.5 when the height of the lesser pelvis is twice the height of the obturator foramen.

CONCLUSION

The analysis and interpretation of cup position and acetabular parameters may be improved by our method for assessing pelvic tilt in AP radiographs.

[Examination of the wrist and hand]

The wrist and hand form a highly complex organ that is of great importance in almost all daily activities. The hand serves as a tool and an organ of sense. Injuries of the hand and wrist as well as mechanical, neurological or systemic inflammatory changes are common. Taking a detailed history can already lead to a diagnosis. Almost all structures of the hand are easily accessible for clinical examination, i. e. inspection, palpation and clinical tests, including dynamic testing. Diagnostic imaging completes the examination procedure.

[Examination of the wrist and hand]

The wrist and hand form a highly complex organ that is of great importance in almost all daily activities. The hand serves as a tool and an organ of sense. Injuries of the hand and wrist as well as mechanical, neurological or systemic inflammatory changes are common. Taking a detailed history can already lead to a diagnosis. Almost all structures of the hand are easily accessible for clinical examination, i. e. inspection, palpation and clinical tests, including dynamic testing. Diagnostic imaging completes the examination procedure.

[Patella navigation in computer-assisted TKA : Intraoperative measurement of patellar kinematics. Video article]

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.

Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?

PURPOSE

The aim of this prospective study is to validate a vector arithmetic method for measuring acetabular cup orientation after total hip arthroplasty (THA) and to verify the clinical practice.

MATERIALS AND METHODS

We measured cup anteversion and inclination of 123 patients after cementless primary THA twice by two examiners on AP pelvic radiographs with a vector arithmetic method and compared with a 3D-CT based reconstruction model within the same radiographic coronal plane.

RESULTS

The mean difference between the radiographic and the 3D-CT measurements was - 1.4° ± 3.9° for inclination and 0.8°± 7.9° for anteversion with excellent correlation for inclination (r = 0.81, p < 0.001) and moderate correlation for anteversion (r = 0.65, p < 0.001). The intraclass correlation coefficient for measurements on radiographs ranged from 0.98 (95 %-CI: 0.98; 0.99) for the first observer to 0.94 (95 %-CI: 0.92; 0.96) for the second observer. The interrater reliability was 0.96 (95 %-CI: 0.93; 0.98) for inclination and 0.93 (95 %-CI: 0.85; 0.96) for anteversion.

CONCLUSION

The largest errors in measurements were associated with an extraordinary pelvic tilt. In order to get a valuable measurement for measuring cup position after THA on pelvic radiographs by this vector arithmetic method, there is a need for a correct postoperative ap view, with special regards to the pelvic tilt for the future.

KEY POINTS

• Measuring acetabular cup orientation on anteroposterior radiographs of the hip after THA is a helpful procedure in everyday clinical practice as a first-line imaging modality• CT remains the golden standard to accurately determine acetabular cup position.• Future measuring on radiographs for cup orientation after THA should account for integration of the pelvic tilt in order to maximize the measurement accuracy. Citation Format: • Craiovan B, Weber M, Worlicek M et al. Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?. Fortschr Röntgenstr 2016; 188: 574 - 581.

[Operative therapy for rheumatoid arthritis of the hand]

The need for operative treatment of severe rheumatic deformities of the hand and wrist is decreasing due to the increased use of disease-modifying drugs; however, some patients do not tolerate or do not sufficiently respond to these drugs, which often results in the hands being affected and in advanced stages to severe deformity and loss of function. In these cases operative surgery can help to slow the progression of rheumatic destruction and restore the function of the patient's hand. This article describes the principles of surgery for rheumatoid arthritis of the hand. A meticulous synovectomy or tenosynovectomy is the first stage of treatment. With progression of rheumatic destruction various salvage procedures are necessary to preserve the best possible functional state.

[Operative treatment of the rheumatic shoulder]

The duration and severity of rheumatic diseases of the shoulder correlate with symptom frequency, structural changes and associated functional limitations. The multifactorial character of the underlying rheumatic disease requires a multimodal therapeutic concept including interaction of surgical and non-surgical disciplines. In addition to basic systemic anti-inflammatory medication, injections targeting the synovial tissue by corticoid instillation and glenohumeral radiosynoviorthesis (with an intact rotator cuff) are further options. Operative interventions on rheumatic shoulders can be characterized as disease-modifying, protective, reconstructive or palliative, depending on the stage. Combining minimally invasive arthroscopic surgical techniques with modern basic therapy has the potential to shift the indications for operative interventions towards an earlier stage of disease without favoring or propagating structural alterations which have already occurred. In cases of severe joint destruction with loss of the rotator cuff, reverse shoulder arthroplasty can be an appropriate option.

[Prevention of periprosthetic joint infections : Not evidence-based strategies]

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.

[Arthrodesis for patients with rheumatic arthritis of the ankle and hindfoot. A reasonable option?]

BACKGROUND

Ankle and hindfoot deformities as well as degenerative changes are often found in patients with rheumatological diseases. They often suffer from severe pain and complain of increasing immobility. Corrective procedures with ankle or hindfoot arthrodesis are promising options.

OBJECTIVES

This article presents epidemiological data and describes the clinical aspects, diagnostics and treatment options for patients with ankle and hindfoot osteoarthritis.

MATERIALS AND METHODS

The retrospective results of 56 patients after ankle or hindfoot arthrodesis are presented.

RESULTS

After an average follow-up of 52 months the majority of results were good or excellent with relief of pain and reconstruction of the function of the foot.

CONCLUSION

Ankle or hindfoot arthrodesis represents a promising option for patients with severe osteoarthritis and can safeguard patients from increasing immobility.

No difference in accuracy between pinless and conventional computer-assisted surgery in total knee arthroplasty

PURPOSE

Many studies have demonstrated higher precision and better radiological results in Total knee arthroplasty (TKA) with computer-assisted surgery (CAS). On the other hand, studies revealed a lengthening of operation time up to 20 min for this technique and demonstrated rare additional complications as fractures and neurovascular injuries caused by the array pins and any intraoperative array dislocation leads to abortion of CAS. To combine the advantages and eliminate the disadvantages of standard CAS, we evaluated the accuracy of a so-called pinless CT-free version of knee navigation (pinless CAS) abandoning the reference pins and reducing the necessary workflow to a minimum.

METHOD

The present study compares the accuracy of the reference methods of two different CT-free knee navigation software versions (Brainlab Knee 2.1 and Brainlab Knee Express 2.5). Thirty patients received TKA assisted by standard CAS. Intraoperatively, the proposed bony resections of standard CAS were matched with the new pinless CAS. Postoperatively, the results were checked by evaluating the radiographs concerning leg axis, femoral flexion and tibial slope.

RESULTS

All results concerning precise cuts (femoral as well as tibial coronal/varus-valgus alignment, femoral flexion alignment and tibial slope, resection height) were comparable between both groups (n.s.). In femoral, we found a mean deviation of coronal alignment of 0.3° (SD 0.7) and flexion of 0.2° (SD 0.8). In tibial, we found a mean deviation of coronal alignment of 0.2° (SD 0.5) and slope of 0.2° (SD 0.6). The mean additional operation time for the pinless CAS was below 2 min. The postoperative mechanical leg axis was within the threshold of 3° in all patients, tibial slope and femoral flexion matched with CAS values.

CONCLUSION

In clinical routine, pinless CAS can comprise the advantages of CAS leaving the disadvantages aside. It reduces surgical time and avoids complications associated with the tracking pins of conventional CAS.

Proximal interphalangeal joint replacement with an unconstrained pyrocarbon prosthesis (Ascension(R)): a long-term follow-up

There have been limited publications that report long-term outcomes of pyrocarbon implants. This report describes both clinical and radiographic long-term results for patients who have been treated with pyrocarbon proximal interphalangeal implants. Thirteen implants in ten patients are reported for an average follow-up of 8.3 years (range 6.2-9.3). All patients were suffering from degenerative joint disease. Five of the 13 digits were free of pain, the remaining eight digits had mild to moderate pain (visual analogue scale 2-5). The average active range of motion was 58° (SD 19°) at latest examination. X-ray results were unremarkable in six digits with an acceptable position of the prosthesis. However, in seven patients significant radiolucent lines (≥ 1 mm) were observed. Three prostheses demonstrated a migration of the proximal component, and one a subsidence of the distal component. Our study does not support the use of this implant for treatment of osteoarthritis of the finger joint owing to high complication rates and limited range of motion.

[Patient satisfaction and muscle torque after total knee replacement in dependence on body mass index]

AIM

In a monocentric study, we investigated patient satisfaction, clinical outcome and isokinetic muscle torque in dependence on the body mass index (BMI) in the mid-term outcome after total knee arthroplasty.

PATIENTS AND METHODS

A group-matched study with two groups (each 40 knee arthroplasties in 40 patients) with a normal body mass index (BMI 20-25) and above 25 was conducted. The groups were matched for sex, diagnosis and age. Satisfaction, HSS score and isokinetic torque parameters with the Cybex 340 system were measured.

RESULTS

There were no differences in the demographic data except for BMI. The HSS score was significantly lower in the overweight group (p = 0.04). Also there were more patients with an HSS score below 60 (bad result) in the group with the higher BMI (0 vs. 9, p = 0.002). Only one patient was not satisfied in the normal weight group, whereas 9 patients in the group BMI > 25 were not satisfied (p = 0.014). No differences between the groups could be found in maximum torque, work and power.

CONCLUSION

The patient satisfaction was much lower in patients with BMI higher than 25. There were no differences between the groups in isokinetic torque parameters.

[Treatment of patellar instability in children and adolescents]

To address recurrent patellar instability in children and young adolescents a variety of therapeutic options exist either as non-operative or operative treatment. Recent options, such as reconstruction of the medial patellofemoral ligament have evoked a new focus of attention on this topic. The intention of this article is to present diverse therapeutic options and to evaluate them by reference to the current literature.

[Importance of computer-assisted navigation in total knee arthroplasty - results of a nationwide survey in Germany]

AIM

Total knee arthroplasty is one of the standard procedures in severe osteoarthritis of the knee. Computer-assisted navigation systems became more popular in the last decade. Navigation systems improve the component positioning and the alignment in total knee arthroplasties. The aim of this survey was to capture the actual trend in computer-assisted total knee arthroplasties in Germany and to discuss the results in comparison to the current literature.

METHODS

A questionnaire form was sent to 506 orthopaedic and trauma surgery departments in Germany. The first part of the survey included general questions about the department and total knee arthroplasties. The surgeons were asked about their application behaviour and their rating of computer-assisted navigation in total knee arthroplasty in the second part. Questions concerning total knee arthroplasties, unicondylar knee arthroplasties and revision total knee arthroplasties were included in the form.

RESULTS

194 of the departments returned the questionnaire. A total of 39 941 knee arthroplasty surgeries were performed in these departments. 35 624 of these surgeries were primary knee arthroplasties including 32 789 total knee arthroplasties and 2835 unicondylar knee arthroplasties. In addition, 4317 revision total knee arthroplasties were performed by the respondents. 60 % of the departments used a computer-assisted navigation system. In synopsis 29 % of the primary total knee arthroplasties, 4 % of the unicondylar knee arthroplasties and 7 % of the revision knee arthroplasties were performed with a computer-assisted navigation system. Minimal invasive surgery was performed in 31 % of the departments and 36 % of these surgeries were done with navigation-assistance. The "ligament-balanced" procedure was the most common used technique to determine the femur rotation in navigated total knee arthroplasties. In 75 % of navigated total knee arthroplasties cemented components were implanted. Overall 65 % of respondents approved of navigation-assisted surgeries and 77 % saw an improved precision by this technique. The number of computer-assisted navigation uses in surgeries is increasing in 34 % of the departments and decreasing in 13 %.

CONCLUSION

The computer-assisted navigation in total knee arthroplasties is a frequently used technique. The most respondents support the application of navigation-assisted knee arthroplasties and indicate an improved outcome measured by the postoperative alignment. Nevertheless, long-term results are needed for a final evaluation of navigation-assisted surgery.

Fatigue fracture of the hinge pin in a semi-constrained total knee arthroplasty: a case report

Material failure is a rare complication in total knee arthroplasty (TKA). This case report shows a fatigue fracture of the hinge pin as a consequence of a postoperative persisting valgus deviation in a semi-constrained TKA.