A clinical decision support system in back pain helps to find the diagnosis: a prospective correlation study.

The aim of this study is to show the concordance of an app-based decision support system and the diagnosis given by spinal surgeons in cases of back pain. 86 patients took part within 2 months. They were seen by spine surgeons in the daily routine and then completed an app-based questionnaire that also led to a diagnosis independently. The results showed a Cramer's V = .711 (p < .001), which can be taken as a strong relation between the tool and the diagnosis of the medical doctor. Besides, in 67.4% of the cases, the diagnosis was concordant. An overestimation of the severity of the diagnosis occurred more often than underestimation (15.1% vs. 7%). The app-based tool is a safe tool to support healthcare professionals in back pain diagnosis.

No clinically significant difference in postoperative pain and side effects comparing conventional and enhanced recovery total hip arthroplasty with early mobilization.

INTRODUCTION: Enhanced recovery after surgery (ERAS) leads to less morbidity, faster recovery, and, therefore, shorter hospital stays. The expected increment of primary total hip arthroplasty (THA) in the U.S. highlights the need for sufficient pain management. The favorable use of short-lasting spinal anesthesia enables early mobilization but may lead to increased opioid consumption the first 24 h (h) postoperatively. METHODS: In a retrospective study design, we compared conventional THA with postoperative immobilization for two days (non-ERAS) and enhanced recovery THA with early mobilization (ERAS group). Data assessment took place as part of the "Quality Improvement in Postoperative Pain Treatment project" (QUIPS). Initially, 2161 patients were enrolled, resulting in 630 after performing a matched pair analysis for sex, age, ASA score (American-Society-of-Anesthesiology) and preoperative pain score. Patient-reported pain scores, objectified by a numerical rating scale (NRS), opioid consumption and side effects were evaluated 24 h postoperatively. RESULTS: The ERAS group revealed higher activity-related pain (p = 0.002), accompanied by significantly higher opioid consumption (p < 0.001). Maximum and minimum pain as well as side effects did not show significant differences (p > 0.05). CONCLUSION: This study is the first to analyze pain scores, opioid consumption, and side effects in a matched pair analyses at this early stage and supports the implementation of an ERAS concept for THA. Taking into consideration the early postoperative mobilization, we were not able to detect a difference regarding postoperative pain. Although opioid consumption appeared to be higher in ERAS group, occurrence of side effects ranged among comparable percentages.

[Coccygodynia-An often underestimated clinical picture]. / Kokzygodynie ­ ein häufig unterschätztes Krankheitsbild.

One of the most frequently underestimated symptoms in orthopedic practices is coccygodynia. The clinical picture of coccygodynia was first described in 1859. Nevertheless, discussions about the importance of coccygeal problems remain a controversial topic. All patients have in common that they have gone through a long ordeal with many therapists, examinations and therapeutic approaches without having received a real diagnosis. The main symptom of coccygodynia is pain directly on the lowest segment of the coccyx, which often only occurs when sitting and is intensified by a change in position, usually from a sitting to a standing position. Trauma can only be described as the trigger in 50% of cases. Women are four times more likely to be affected than men. The gold standard for imaging should be viewed from standing and seated dynamic lateral radiographs of the coccyx. After the diagnosis has been made, conservative treatment should first be started with oral nonsteroidal anti-inflammatory drugs (NSAID), relief with a coccyx cushion with a recess and, if necessary, physiotherapy to strengthen or loosen the pelvic floor. Local infiltration with a glucocorticoid and a local anesthetic directly in the painful area are also often promising. If the symptoms persist for more than 6 months, surgical treatment in the sense of removing the coccyx can be discussed with the patient. The literature shows a success rate of 80-90% if the indications are correct.

[Osteoporotic vertebral fractures-From diagnosis to treatment]. / Osteoporotische Wirbelkörperfrakturen ­ Von der Diagnose zur Therapie.

The aim of the present work is an overview of current concepts in the treatment of osteoporotic vertebral fractures, risk factors, clinical presentation and conservative and operative management. Osteoporotic vertebral fractures are a widespread problem, affecting between 700,000 and 1.5 million adults annually in the USA alone. Osteoporotic vertebral fractures can cause severe physical impairment, including back pain, dysfunction, and progressive thoracic kyphosis. Mortality after osteoporotic vertebral fractures is still increased compared to age-matched controls. In the reality of care, advocates of purely conservative therapy as well as advocates of surgical treatment can be found all over the world. In summary, understanding the risk factors, appropriate clinical evaluation and treatment strategies are crucial. When surgery is indicated, balloon kyphoplasty shows significantly better pain reduction and lower mortality compared to nonsurgical treatment.

Pelvic tilt impacts cup orientation on CT: how accurate is the gold standard?

BACKGROUND: Computed tomography (CT) is the gold standard for the accurate measurement of cup inclination and anteversion in total hip arthroplasty (THA). However, functional cup position strongly depends on the tilt of the pelvis and thus pelvic tilt in the supine position on the CT table harbors the risk of misinterpretation. PURPOSE: To evaluate the influence of pelvic tilt on cup measurements in postoperative CT scans. MATERIAL AND METHODS: This is a secondary outcome analysis of a prospective study. In 123 patients undergoing THA, anatomic cup inclination and anteversion as measured on postoperative 3D-CT scans were compared between: (i) the anterior pelvic plane (APP) resembling neutral pelvic tilt; and (ii) the coronal plane representing the standard planes on CT. Furthermore, the effect of the variation on cup positions within Lewinnek's safe zone in relation to the applied reference plane was assessed. RESULTS: Mean pelvic tilt in supine position was -3.5° ± 5.6°. This resulted in a mean difference for anteversion between APP und coronal plane of 2.1° ± 3.7° and of 2.1° ± 1.9° for cup inclination, respectively. The change varied up to 20.2° for cup inclination and up 12.2° for cup anteversion. The overall conversion rate for inclination and/or anteversion regarding Lewinnek's safe zone was high at 23.6% (29/123). CONCLUSION: Pelvic tilt affects cup orientation on CT scans depending on the applied reference plane. Standard CT planes should be corrected regarding pelvic tilt before measurements to avoid errors in measurement.

A novel radiological classification for displaced os coccyx: the Benditz-König classification.

BACKGROUND: Treatment of coccygodynia is still a challenging entity. Clear surgical selection criteria are still lacking. The aim of the investigation was to establish a novel radiological classification for surgical decision-making in coccygodynia cases. MATERIAL AND METHODS: Retrospective analysis of standing and sitting X-rays of coccygodynia patients referred to a single centre from 2018 to 2020. The sacro-coccygeal angle (SCA), the intra-coccygeal angle (ICA) and the difference of the intervertebral disc height (∆IDH) were measured. All coccyges were distributed in subtypes and correlated with the patients' treatment. RESULTS: In total, 138 patients (female/male: 103/35) with a mean age of 45.6 ± 15.4 years were included in the study. In total, 49 patients underwent coccygectomy. Four different subtypes of displaced coccyges were identified: Type I with a non-segmented coccyx, anterior pivot, increased SCA and ICA from standing to sitting, ∆IDH = 1.0 ± 1.5 mm. Type II with a multisegmented coccyx, anterior pivot, increased SCA and ICA standing/sitting, ∆IDH = 1.1 ± 1.6 mm. Type III showed a posterior pivoted coccyx, negative SCA and ICA, ∆IDH = 0.6 ± 1.6 mm. Type IV is characterized by an anterior-posterior dissociation of the tail bone with a positive SCA, and the ICA shifted from a posterior to an anterior orientation. ∆IDH was - 0.6 ± 1.8 mm. CONCLUSION: The presented radiological classification could help to facilitate the surgical decision-making for patients with displaced os coccyx. In addition, lateral and sitting X-rays were easy to perform and did not need unnecessary ionizing radiation like in CT scans and were more cost-effective than MRI investigations. The subtypes III and especially IV were more likely leading to surgery.

Increase in Lower Limb Strength after Multimodal Pain Management in Patients with Low Back Pain.

Background and Objectives: The aim of the present study was to evaluate the efficacy of a multimodal pain therapy (MPM) regarding the objective parameter muscle strength of segment-dependent lower limb muscle groups before and after such a treatment. Materials and Methods: 52 patients with a history of low back pain and/or leg pain received standardized multimodal pain management. Strength of segment indicating lower limb muscles were assessed for each patient before and after ten days of treatment by handheld dynamometry. Results: Overall strength increased significantly from 23.6 kg ± 6.6 prior to treatment to 25.4 ± 7.3 after treatment, p ≤ 0.001. All muscle groups significantly increased in strength with exception of great toe extensors. Conclusions: Despite lower basic strength values at the beginning of treatment, all investigated muscle groups, except for the great toe extensors, showed a significant increase of overall strength after completion of the multimodal pain management concept. Increased overall strength could help with avoiding further need of medical care by supporting patients' autonomy in daily life activities, as well as maintaining working abilities. Thus, our study is the first to show a significant positive influence on lower limb strength in patients with low back pain after a conservative MPM program.

Pros and cons of navigated versus conventional total knee arthroplasty-a retrospective analysis of over 2400 patients.

INTRODUCTION: Because of the ongoing discussion of imageless navigation in total knee arthroplasty (TKA), its advantages and disadvantages were evaluated in a large patient cohort. METHODS: This retrospective analysis included 2464 patients who had undergone TKA at a high-volume university arthroplasty center between 2012 and 2017. Navigated and conventional TKA were compared regarding postoperative mechanical axis, surgery duration, complication rates, one-year postoperative patient-reported outcome measures (PROMs) (WOMAC and EQ-5D indices), and responder rates as defined by the criteria of the Outcome Measures in Rheumatology and Osteoarthritis Research Society International consensus (OMERACT-OARSI). RESULTS: Both navigated (1.8 ± 1.6°) and conventional TKA (2.1 ± 1.6°, p = 0.002) enabled the exact reconstruction of mechanical axis. Surgery duration was six minutes longer for navigated TKA than for conventional TKA (p < 0.001). Complication rates were low in both groups with comparable frequencies: neurological deficits (p = 0.39), joint infection (p = 0.42 and thromboembolic events (p = 0.03). Periprosthetic fractures occurred more frequently during conventional TKA (p = 0.001). One-year PROMs showed excellent improvement in both groups. The WOMAC index was statistically higher for navigated TKA than for conventional TKA (74.7 ± 19.0 vs. 71.7 ± 20.7, p = 0.014), but the increase was not clinically relevant. Both groups had a similarly high EQ-5D index (0.23 ± 0.24 vs. 0.26 ± 0.25, p = 0.11) and responder rate (86.5% [256/296] vs. 85.9% [981/1142], p = 0.92). CONCLUSION: Both methods enable accurate postoperative leg alignment with low complication rates and equally successful PROMs and responder rates one year postoperatively. LEVEL OF EVIDENCE: III. Retrospective cohort study.

The effects of soft tissue lateral release on the stability of the ligament complex of the knee.

PURPOSE: Valgus deformity presents a particular challenge in total knee arthroplasty. This condition regularly leads to contractures of the lateral capsular ligament complex and to overstretching of the medial ligamentous complex. Reconstruction of the knee joint kinematics and anatomy often requires lateral release. However, data on how such release weakens the stability of the knee are missing in the literature. This study investigated the effects of sequential lateral release on the collateral stability of the ligament complex of the knee in vitro. METHODS: Ten knee prostheses were implanted in 10 healthy cadaveric knee joints using a navigation device. Soft tissue lateral release consisted of five release steps, and stiffness and stability were determined at 0, 30, 60 and 90° flexion after each step. RESULTS: Soft tissue lateral release increasingly weakened the ligament complex of the lateral compartment. Because of the large muscular parts, the release of the iliotibial band and the M. popliteus had little effect on the stability of the lateral and medial compartment, but release of the lateral ligament significantly decreased the stability in the lateral compartment over the entire range of motion. Stability in the medial compartment was hardly affected. Conversely, further release of the posterolateral capsule and the posterior cruciate ligament led to the loss of stability in the lateral compartment only in deep flexion, whereas stability decreased significantly in the medial compartment. CONCLUSION: Our study shows for the first time the association between sequential lateral release and stability of the ligamentous complex of the knee. To maintain the stability, knee surgeons should avoid releasing the entire lateral collateral ligament, which would significantly decrease stability in the lateral compartment.

Kinematic alignment in total knee arthroplasty leads to a better restoration of patellar kinematics compared to mechanic alignment.

PURPOSE: The influence of different implantation techniques in TKA on tibiofemoral kinematics was analysed in few investigations so far. However, the influence on patellar kinematics remain unclear. The aim of the present investigation was to compare patellar kinematics of the natural knee with those of knees after both kinematically and mechanically aligned TKAs. METHODS: Patellar kinematics of ten cadaveric knees before and after TKAs implanted using both a kinematic and mechanic alignment technique were investigated and compared using a commercial optical computer navigation system. RESULTS: There was a statistically significant difference between natural patellar kinematics and both implantation techniques analysing mediolateral shift. Patellar lateral tilt showed significant better results in the kinematically compared to the mechanically aligned TKAs. In terms of patella rotation, the patella of both mechanically and kinematically aligned TKAs showed significant higher values for external rotation compared to the natural knee. Regarding epicondylar distance again a significant better restoration of natural kinematics could be found in the kinematically aligned TKAs. CONCLUSION: Kinematically aligned TKAs showed a better overall restoration of patellar kinematics compared to a conventional mechanical alignment technique. In terms of clinical usefulness, the present study highlights the potential benefit for clinical outcome using a kinematically aligned implantation technique in TKA to achieve a better restoration of natural patellofemoral kinematics.

Weakening of the knee ligament complex due to sequential medial release in total knee arthroplasty.

PURPOSE: The purpose of this study was to investigate the effects of sequential medial release on the stiffness and collateral stability of the ligament complex of the knee. Irrespective of the implantation technique used, varus deformity frequently requires release of the capsular ligament complex. Yet, no data are available on how stiffness and stability of the knee ligament complex are weakened by such release. METHODS: After total knee arthroplasty, ten healthy Thiel-fixed knee joints were subjected to sequential medial release consisting of six release steps. After each step, stiffness and stability were determined at 0°, 30°, 60°, and 90°. RESULTS: Sequential medial release increasingly weakened the ligament complex. In extension, release of the anteromedial tibial sleeve 4 cm below the joint line already weakened the ligament complex by approximately 13%. Release 6 cm below the joint line reduced stiffness and stability by 15-20% over the entire range of motion. After detachment of the medial collateral ligament, stability was only about 60% of its initial value. CONCLUSION: Our study showed for the first time the association between medial release and stiffness and stability of the knee ligament complex. To maintain stability, vigorous detachment of the knee ligament complex should be avoided. Release of the anteromedial tibial sleeve already initiates loss of stability. The main stabiliser is the medial ligament, which should never be completely detached. LEVEL OF EVIDENCE: IV.

Efficiency and predictive parameters of outcome of a multimodal pain management concept with spinal injections in patients with low back pain: a retrospective study of 445 patients.

Low back pain is one of the most common diseases of modern civilization. Multimodal pain management (MPM) represents a central approach to avoiding surgery. Short-term results are published rarely and often incomparable because of different treatment concepts. This study compared the subjective and objective parameters as well as the anamnestic and clinical parameters of 445 patients with low back pain before and after inpatient MPM to investigate the influence of this type of therapy on short-term outcome. The majority of patients were very satisfied (39%) or satisfied (58%) with the treatment outcome. The median pain reduction for back pain was 3.0 (IQR 2.88) (numeric rating scale, NRS), thus 66% and 2.75 (IQR 3.38, 62%) for leg pain. The main pain reduction occurred within the first 10 days of treatment and was clinically significant from day 5 onwards. The outcome for patients with hospitalization of more than 10 days was significantly worse. The parameters female sex, BMI of > 30, local pain, and pain duration of 3-24 months had a significantly better outcome. In contrast, age, treatment cause, depression, anxiety, and other diseases had no statistically significant influence on outcome. MPM therapy for more than 5 days seems to be an efficient short-term approach to treating low back pain. Knowledge of some of the outcome predictors helps to early identify patients who require more intensive individual care. In the case of no clear indication for surgery, MPM can be an appropriate treatment option.

Course of pain after total hip arthroplasty within a standardized pain management concept: a prospective study examining influence, correlation, and outcome of postoperative pain on 103 consecutive patients.

INTRODUCTION: Postoperative pain management options are of great importance for patients undergoing total hip arthroplasty, as joint replacement surgery is reported to be one of the most painful surgical procedures. This study demonstrates pain outcome until 4 weeks postoperatively and evaluates factors influencing pain in the postoperative course after total hip arthroplasty. MATERIALS AND METHODS: A total of 103 patients were included in this prospective cohort trial and underwent total hip arthroplasty. Postoperative pain was described using a numerical rating scale (NRS); demographic data and perioperative parameters were correlated with postoperative pain. RESULTS: Evaluation of pain scores in the postoperative course showed a constant decrease in the first postoperative week (mean NRS 3.1 on day 1 to mean NRS 2.3 on day 8) and, then, a perpetual increase for 3 days (mean NRS 2.6 on day 9 to mean NRS 2.3 on day 12). Afterwards, a continuous pain-level decrease was stated (continuous to a mean NRS 0.9 on day 29). No correlation was found between the potential influencing factors sex, age, body mass index, duration of surgery, ASA score, and postoperative pain levels, but a high significant correlation could be stated for preoperative pain levels and postoperative pain intensity (pain while moving p < 0.02 to p < 0.05 depending on the time period "week 1 postoperatively", "week 2-4", or "week 1-4"; pain while resting p < 0.001, in all the measured time intervals, respectively). CONCLUSION: Increasing pain levels after the first week postoperatively, for 3 days, are most likely to be caused by the change to more extensive mobilization and physiotherapy in the rehabilitation unit. No significant influence or correlation on the intensity of postoperative pain could be found while evaluating potential predictors except preoperative pain levels. Pain management has to take these findings into account in the future to further increase patients' satisfaction in the postoperative course after total hip arthroplasty and to adapt pain management programs.

No Clinical Difference Comparing General, Regional, and Combination Anesthesia in Hip Arthroplasty: A Multicenter Cohort-Study Regarding Perioperative Pain Management and Patient Satisfaction.

BACKGROUND: Steadily increasing numbers of hip arthroplasties are reported in the past years. Different types of anesthetic methods for surgery itself as well as pain management programs have been established. It is one of the main goals to reduce postoperative pain levels and guarantee better and faster mobilization in the postoperative period. The present study aims to compare the use of general and regional spinal anesthesia and their combination regarding perioperative pain management and patient satisfaction. METHODS: All patients included in the present study had undergone primary hip arthroplasty. Parameters were analyzed on the first postoperative day within the scope of the "Quality Improvement in Postoperative Pain Management" project, which is conducted nationwide in 49 orthopedic departments at the time of data evaluation. RESULTS: From 2009-2015, 18,118 patients underwent primary hip arthroplasty and have been evaluated. Demographic and general patient data were homogenous. The need for opioids was significantly higher in patients where general and combination anesthesia was applied (P < .001, respectively). Pain scores and pain management satisfaction were significantly better in regional and combination anesthesia (P < .001, respectively). CONCLUSION: We were able to show a highly significant advantage in the use of regional or the combination of regional and general anesthesia in comparison with general anesthesia alone in hip arthroplasty regarding patients' satisfaction and the requirement of opioid pain medication, although maybe below clinical relevance.

Presence of rotational errors in long leg radiographs after total knee arthroplasty and impact on measured lower limb and component alignment.

PURPOSE: Rotation of the lower limb in weight bearing long leg radiographs has a great impact on measured component and lower limb alignment parameters. We asked which rotational errors of long leg radiographs are present in a high volume centre and which radiological and clinical consequences arise regarding measured coronal component and lower limb alignment after total knee arthroplasty. METHODS: In 100 long leg radiographs coronal femoral and tibial component alignment and hip knee ankle angle (HKA) were measured. Present rotational errors in long leg radiographs were determined by fibular overlap and its impact on alignment parameters calculated. RESULTS: A mean internal rotation of 8.1° (9.3 SD) with a range between 36° of internal and 16° of external rotation was found in long leg radiographs. This resulted in mean differences between measurements before and after rotational correction regarding femoral and tibial component alignment and HKA of 0.6-0.8° (range 3.5° valgus and 1.6° varus error). Clinically, 11 out of 100 patients were wrongly assigned to either mal- or well-alignment (neutral mechanical alignment within ±3° varus or valgus). CONCLUSION: Surgeons should be aware of potential rotational errors in long leg radiographs after total knee arthroplasty resulting in wrong measurements. In case of rotational errors, radiographs should be repeated or rotational corrections calculated. For study purposes only radiographs after rotational correction should be accepted.

Radiological outcome of postoperative sagittal balance on standing radiographs in comparison to intraoperative radiographs in prone position when performing lumbar spinal fusion.

PURPOSE: Aim of this study is to show the outcome of postoperatively measured lumbar lordosis in upright position in comparison to the intraoperatively estimated lumbar lordosis in prone position, as the lumbar lordosis is one of the most important factors for the clinical outcome after spinal fusion. MATERIALS AND METHODS: Eighty-two patients, receiving lumbar fusion were included in this retrospective study. Intraoperative radiographs were scanned. Then radiographs of the whole spine pre- and postoperatively, as well as 1 year after surgery were measured by a spine surgeon and a radiologist. The visible segment lordosis angles were measured and compared (L2-S1, L3-S1, L4-S1, L5-S1). In addition, the pelvic parameters pelvic incidence, pelvic tilt and sacral slope were measured pre- and postoperatively. RESULTS: The intraobserver reliability was almost perfect. The mean lordosis angle L4-S1 was 32.6° ± 7.8° intraoperatively and 29° ± 10.8° postoperatively. A linear correlation of these two measurements can be seen. In mean, the postoperative lordosis is 4° smaller than intraoperatively. This trend can also be seen in the level L3-S1. In levels L2-S1 and L5-S1 the postoperative values were slightly higher than intraoperatively, but without any significance. Also, 1 year after surgery there were no significant changes in global lumbar lordosis. CONCLUSION: Measuring lordosis angles intraoperatively resulted in almost the same values as measurements in standing plane radiographs postoperatively, despite prone position. These findings could especially be shown for the level L4-S1. The intraobserver reliability was almost perfect for both, intra- and postoperative measurements. In conclusion, the intraoperative measurement of a lumbar lordosis angle can perfectly predict the postoperative result.

No difference in patellar kinematics between fixed-bearing cruciate-retaining and cruciate-substituting total knee arthroplasty: a cadaveric investigation.

PURPOSE: The influence of cruciate-ligament-retaining (CR-TKA) and cruciate-ligament-substituting (CS-TKA) TKA on tibiofemoral kinematics was analysed in many investigations. However, the influence on patellar kinematics is unclear so far. The aim of this study was to compare patellar kinematics of the natural knee with those after CR- and CS-TKA. METHODS: Patellar kinematics of nine healthy whole-body cadaveric knees before and after CR- and CS-TKA was investigated using a commercial optical computer navigation system. Patellar kinematics of the healthy knee was compared with those after CR- and CS-TKA. RESULTS: No significant difference between the natural knee and the knee after TKA or between both types of TKA for patellar kinematics could be found. Interestingly, both types of TKA resulted in a more medial patellar shift and a contrary patellar tilt and rotation behaviour. CR- and CS-TKA resulted in smaller values for patellar epicondylar distance at all flexion angles. CONCLUSIONS: Our study found no influence of prosthesis type on patellar kinematics. Factors like component alignment and prosthesis design seem to be more important in terms of adequate restoration of patellar kinematics in TKA than whether choosing CR- or CS-TKA.

[Treatment options for coccygodynia]. / Therapieoptionen bei der Coccygodynie.

BACKGROUND: To this day, patients with coccyx problems are the most frequently underestimated patient population in orthopedic practices. The clinical picture of coccygodynia was first described in 1859. Nevertheless, discussions about the importance of coccyx problems remain a tiresome topic. All patients have in common that they have gone through a long ordeal with many therapists, examinations and therapeutic approaches without having received a real diagnosis. DIAGNOSTIC: The main symptom of coccygodynia is the pain directly on the lowest segment of the coccyx, which often only occurs when sitting and is intensified by the change in position, usually from a sitting to a standing position. Trauma can only be described as the trigger in 50% of cases. Women are four times more likely to be affected than men. The gold standard for imaging should be viewed from standing and seated dynamic lateral radiographs of the coccyx. TREATMENT: After the diagnosis has been made, conservative treatment should first be started with oral NSAIDs, relief with a coccyx cushion with a recess and, if necessary, physiotherapy to strengthen or loosen the pelvic floor. Local infiltrations with a glucocorticoid and local anesthetic directly in the painful area are also often promising. If the symptoms persist for more than 6 months, surgical treatment in the sense of removing the coccyx can be discussed with the patient. The literature shows a success rate of 80-90% if the indication was correct.

Polyethylene liner dissociation in cementless total hip arthroplasty: Ensuring accurate diagnosis.

BACKGROUND: Uncemented acetabular components are widely used in modern total hip arthroplasty (THA). Modularity has numerous advantages including the ability to use supplementary screw fixation for the shell, and allow to switch from ceramic to polyethylene (PE) bearings and vice versa, and the use of lipped and face-changing liners. OBJECTIVE: Despite these advantages, a problem with modular PE liners is dissociation. This is a rare complication in modern implants. The rate of liner dissociation is reported to be very low between 0.17% and 0.8%. Typical symptoms are sudden onset of groin pain in a previously well-functioning hip joint, followed by grinding or clicking sensations during hip joint motions indicating, that the femoral head is articulating with the metal acetabular shell rather than with the PE liner. Any newly observed noise or squeaking from a THA should undergo radiographic investigation to exclude liner dissociation. CASE PRESENTATION: We present the case of an 88-yearold male patient who developed PE liner dissociation in a cementless THA with a Pinnacle acetabular component six years after the index operation. We recommended revision of the left hip, which was performed two days later. In the interim, the patient was advised to use a pair of crutches. During revision surgery, it was observed that the metal head made contact with the cementless cup shell without damaging it from a macroscopic standpoint. Consequently, a simple exchange of the PE liner was conducted, and a 36 mm metal head was implanted due to scratches on the original head. CONCLUSION: Early diagnosis facilitates a straightforward exchange of the liner along with the head, potentially preserving the osseous integrated cup shell and stem integrity. Routine radiologic follow-up allows to distinguish between PE liner dissociation and severe PE wear.

No Success without Effort: Follow-Up at Six Years after Implementing a Benchmarking and Feedback Concept for Postoperative Pain after Total Hip Arthroplasty.

BACKGROUND: Total hip arthroplasty (THA) is still ranked among the operations with the highest postoperative pain scores. Uncontrolled postsurgical pain leads to prolongated hospital stays, causes more frequent adverse reactions and can induce chronical pain syndromes. In 2014, we implemented a standardized, multidisciplinary pain management concept with continuous benchmarking at our tertiary referral center by using the "Quality Improvement in Postoperative Pain Management" (QUIPS) program with excellent results over a period of two years. The initial study ended in 2016 and we aimed to evaluate if it was possible to obtain the excellent short-term results over a period of six years without any extra effort within the daily clinical routine. MATERIALS AND METHODS: In a retrospective study design, we compared postoperative pain, side effects and functional outcome after primary THA for 2015 and 2021, using validated questionnaires from the QUIPS project. In contrast to the implementation of the pain management concept in 2014, the weekly meetings of the multidisciplinary health care team and special education for nurses were stopped in 2021. Data assessment was performed by an independent pain nurse who was not involved in pain management. RESULTS: Altogether, 491 patients received primary THA in 2015 and 2021 at our tertiary referral center. Collected data revealed significantly worse maximum and activity-related pain (both p < 0.001) in combination with significantly higher opioid consumption in comparison to implementation in 2015. Though the patients reported to be less involved in pain management (p < 0.001), the worse pain scores were not reflected by patient satisfaction which remained high. While the participation rate in this benchmarking program dropped, we still fell behind in terms of maximum and activity-related pain in comparison to 24 clinics. CONCLUSION: Significantly worse pain scores in combination with higher opioid usage and a lower hospital participation rate resemble a reduced awareness in postoperative pain management. The significantly lower patient participation in pain management is in line with the worse pain scores and indirectly highlights the need for special education in pain management. The fact patient satisfaction appeared to remain high and did not differ significantly from 2015, as well as the fact we still achieved an acceptable ranking in comparison to other clinics, highlight the value of the implemented multidisciplinary pain management concept.