Description of pain associated with persistent postoperative pain after total knee arthroplasty

After total knee arthroplasty (TKA), approximately 20% of patients experience persistent postoperative pain (PPP). Although preoperative and postoperative pain intensity is a relevant factor, more detailed description of pain is needed to determine specific intervention strategies for clinical conditions. This study aimed to clarify the associations between preoperative and postoperative descriptions of pain and PPP. Fifty-two TKA patients were evaluated for pain intensity and description of pain preoperatively and 2 weeks postoperatively, and the intensities were compared. In addition, the relationship between pain intensity and PPP at 3 and 6 months after surgery was analyzed using a Bayesian approach. Descriptions of arthritis ("Throbbing" and "aching") improved from preoperative to 2 weeks postoperative. Several preoperative ("Shooting", "Aching", "Caused by touch", "Numbness") and postoperative ("Cramping pain") descriptors were associated with pain intensity at 3 months postoperatively, but only "cramping pain" at 2 weeks postoperatively was associated with the presence of PPP at 3 and 6 months postoperatively. In conclusion, it is important to carefully listen to the patient's complaints and determine the appropriate intervention strategy for the clinical condition during perioperative pain management.

Subcortical brain anatomy as a potential biomarker of persistent pain after total knee replacement in osteoarthritis

ABSTRACT

The neural mechanisms for the persistence of pain after a technically successful arthroplasty in osteoarthritis (OA) remain minimally studied, and direct evidence of the brain as a predisposing factor for pain chronicity in this setting has not been investigated. We undertook this study as a first effort to identify presurgical brain and clinical markers of postarthroplasty pain in knee OA. Patients with knee OA (n = 81) awaiting total arthroplasty underwent clinical and psychological assessment and brain magnetic resonance imagining. Postoperative pain scores were measured at 6 months after surgery. Brain subcortical anatomic properties (volume and shape) and clinical indices were studied as determinants of postoperative pain. We show that presurgical subcortical volumes (bilateral amygdala, thalamus, and left hippocampus), together with shape deformations of the right anterior hippocampus and right amygdala, associate with pain persistence 6 months after surgery in OA. Longer pain duration, higher levels of presurgical anxiety, and the neuropathic character of pain were also prognostic of postsurgical pain outcome. Brain and clinical indices accounted for unique influences on postoperative pain. Our study demonstrates the presence of presurgical subcortical brain factors that relate to postsurgical persistence of OA pain. These preliminary results challenge the current dominant view that mechanisms of OA pain predominantly underlie local joint mechanisms, implying novel clinical management and treatment strategies.

Advances in the management of persistent pain after total knee arthroplasty

PURPOSE OF REVIEW

Total knee arthroplasty (TKA) is one of the most commonly performed surgical procedures, with additional growth anticipated as the US population ages. Because the prevalence of chronic postsurgical pain ranges from 15 to 25%, identifying persons at risk for persistent pain following surgery allows for preoperative optimization of risk factors as well as early identification and intervention in the postsurgical period.

RECENT FINDINGS

Clinical understanding of available management techniques is critical to management, which should focus on improving patient mobility and satisfaction while reducing patient disability and healthcare costs. Current evidence supports a multimodal management strategy. This includes pharmacologic and nonpharmacologic interventions, procedural techniques, and identification and optimization of psychosocial and behavioral contributors to chronic pain. Procedural techniques known to confer analgesia include radiofrequency and watercooled neurotomy techniques. More recently, case reports have been published describing analgesic benefit with central or peripheral neuromodulation as a novel, though more invasive analgesic therapy.

SUMMARY

Identification and early intervention to address persistent pain after TKA is important to optimize patient outcomes. The anticipated growth in TKA underscores the need for future investigations to more fully define potential therapies for chronic pain following TKA.

Regional brain atrophy in patients with chronic ankle instability: A voxel-based morphometry study

The objective of this study was to investigate whether brain volume changes occur in patients with chronic ankle instability (CAI) using voxel-based morphometry and assessing correlations with clinical tests. Structural magnetic resonance imaging data were prospectively acquired in 24 patients with CAI and 34 healthy controls. CAI symptoms and pain intensity were assessed using the Foot and Ankle Ability Measure (FAAM), Cumberland Ankle Instability Tool (CAIT), American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, and visual analog scale (VAS). The gray matter volume (GMV) of each voxel was compared between the two groups while controlling for age, sex, weight, and education level. Correlation analysis was performed to identify associations between abnormal GMV regions and the FAAM score, AOFAS score, VAS score, disease duration, and body mass index. Patients with CAI exhibited reduced GMV in the right precentral and postcentral areas, right parahippocampal area, left thalamus, left parahippocampal area, and left postcentral area compared to that of healthy controls. Furthermore, the right parahippocampal (r = 0.642, p = 0.001), left parahippocampal (r = 0.486, p = 0.016), and left postcentral areas (r = 0.521, p = 0.009) were positively correlated with disease duration. The left thalamus was positively correlated with the CAIT score and FAAM activities of daily living score (r = 0.463, p = 0.023 and r = 0.561, p = 0.004, respectively). A significant positive correlation was found between the local GMV of the right and left parahippocampal areas (r = 0.487, p = 0.016 and r = 0.763, p < 0.001, respectively) and the AOFAS score. Neural plasticity may occur in the precentral and postcentral areas, parahippocampal area, and thalamus in patients with CAI. The patterns of structural reorganization in patients with CAI may provide useful information on the neuropathological mechanisms of CAI.

Preoperative pain catastrophizing affects pain outcome after total knee arthroplasty

BACKGROUNDS

Preoperative widespread pain sensitization or pain catastrophizing could be associated with chronic pain after total knee arthroplasty (TKA). The aim of the present study was to examine the association between postoperative pain in patients undergoing TKA and preoperative factors, including patient characteristics and preoperative central sensitization as well as pain catastrophizing.

METHODS

Preoperative TKA patients were evaluated using the Central Sensitization Inventory (CSI)-9 and Pain Catastrophizing Scale (PCS). Postoperative knee pain was evaluated using a numerical rating scale (NRS) 6 months after TKA. Statistical analyses were performed to assess the relationship between NRS 6 months after TKA and preoperative factors, including patient characteristics, CSI-9, and PCS.

RESULTS

We enrolled 58 consecutive patients with osteoarthritis who underwent TKA. Using cutoff of 14, postoperative NRS was higher in the patients with ≥14 than the patients with <14 in CSI (p = 0.025). Postoperative NRS was higher in the patients with ≥30 than the patients with <30 in PCS (p = 0.043). Preoperative PCS was a significant risk factor of postoperative pain using a multivariate analysis.

CONCLUSIONS

Surgeon should recognize preoperative PCS could affect postoperative pain 6 months after TKA.

A new robotically assisted system for total knee arthroplasty: A sheep model study

BACKGROUND

We investigated the accuracy and safety of a new HURWA robotic-assisted total knee arthroplasty (TKA) system in a sheep model.

METHODS

Ten male small-tailed Han sheep were used in this study. Sheep were imaged by computed tomography scan before and after bone resection and the cutting errors between actual bone preparation and preoperative planning of the femur and tibia in three dimensions were measured.

RESULTS

The overall accuracies after surgery compared with that from preoperative surgical planning of the left and right femurs were 1.93 ± 1.02° and 1.93 ± 1.23°, respectively. Additionally, similarly high overall accuracies for the left and right tibia of 1.26 ± 1.04 and 1.68 ± 0.92°, respectively, were obtained. The gap distances of the distal cut, anterior chamfer, anterior cut, posterior chamfer and posterior cut on the medial side were 0.47 ± 0.35 mm, 0.41 ± 0.37 mm, 0.12 ± 0.26 mm, 0.41 ± 0.44 mm and 0.12 ± 0.23 mm, respectively. No intraoperative complications, such as intraoperative fracture, massive bleeding or death, occurred.

CONCLUSION

This new HURWA robotic-assisted TKA system is an accurate and safe tool for TKA surgery based on the sheep model.