Atypical influence of biomechanical knowledge in Complex Regional Pain Syndrome-towards a different perspective on body representation.

Part of the multifaceted pathophysiology of Complex Regional Pain Syndrome (CRPS) is ascribed to lateralized maladaptive neuroplasticity in sensorimotor cortices, corroborated by behavioral studies indicating that patients present difficulties in mentally representing their painful limb. Such difficulties are widely measured with hand laterality judgment tasks (HLT), which are also used in the rehabilitation of CRPS to activate motor imagery and restore the cortical representation of the painful limb. The potential of these tasks to elicit motor imagery is critical to their use in therapy, yet, the influence of the body's biomechanical constraints (BMC) on HLT reaction time, supposed to index motor imagery activation, is rarely verified. Here we investigated the influence of BMC on the perception of hand postures and movements in upper-limb CRPS. Patients were slower than controls in judging hand laterality, whether or not stimuli corresponded to their painful hand. Reaction time patterns reflecting BMC were mostly absent in CRPS and controls. A second experiment therefore directly investigated the influence of implicit knowledge of BMC on hand movement judgments. Participants judged the perceived path of movement between two depicted hand positions, with only one of two proposed paths that was biomechanically plausible. While the controls mostly chose the biomechanically plausible path, patients did not. These findings show non-lateralized body representation impairments in CRPS, possibly related to difficulties in using correct knowledge of the body's biomechanics. Importantly, they demonstrate the challenge of reliably measuring motor imagery with the HLT, which has important implications for the rehabilitation with these tasks.

Effect of splint on pain, function and quality of life in trapeziometacarpal osteoarthritis patients?

Trapeziometacarpal (TM) Osteoarthritis is one of the most common osteoarthritis. It causes pain, loss of mobility and strength and affected function in daily life. Splint is one of the conservative treatments proposed to patients. The purpose of this study was to assess the effect of this conservative treatment on pain, function and quality of life at long-term. We sent 193 questionnaires to patients who received a CMC splint for their TM osteoarthritis. The CMC splint immobilizes only the TM joint and leaves free the interphalangeal joint of the thumb and the wrist. First, we comptuted how many patients had finally undergone surgical treatment. On the non-operated patients, we analyzed the pain (VAS), the function (QuickDASH score) and the quality of life (SF-12). We compared the results to literature and norms. Finally, 186 people could be included in the study ,115 we answered and 28 were operated on (24%). After 4 years (3.8±1.7 yrs) of conservative treatment, The VAS and QuickDASH scores were significantly worse comparatively to a cohort of healthy patients, trapezectomy and arthrodesis patients. The SF-12 scores were reduced from 20% comparative to norms. In conclusion, few patients had surgery after splinting as a conservative treatment. However, these non- operated patients do not provide good results.

Trapeziometacarpal prosthesis: an updated systematic review.

The trapeziometacarpal prosthesis is mostly used in Europe to treat osteoarthritis of the basal joint of the thumb. Its supposed benefits are that it restores the length of the thumb, improves strength, function and mobility while reducing recovery time compared to other surgical treatments. However, previous reviews of the literature could not confirm these assumptions. This article provides an updated systematic review to help answer to these questions through a methodical statistical analysis and to quantify the two main complications, namely failure and deep infection. To achieve these aims, a selection of articles including implant case series was done in the Medline database based on specific criteria. Data about pain, function, strength, infection, and failure were compiled and a statistical analysis was performed. Results show a fast recovery in terms of pain and function but the positive effect on strength seems limited. The failure rate represented by the revision rate is high and the deep infection rate is fairly low. Randomized controlled studies are needed to obtain reliable data to compare the prosthesis to other surgical treatments.

Trapeziometacarpal total joint replacement as an alternative to trapeziectomy depends on trapezium height: Retrospective study of 67 patients.

Surgical indications for trapeziometacarpal (TMC) total joint replacement for thumb basal joint osteoarthritis (OA) are increasing. However, complications following this procedure are not insignificant. To avoid complications, preoperative planning with measurement of trapezium height is indicated to ensure a cup is not implanted in the trapezium if its height is less than 8 millimeters. The objective of our study was to analyze a series of preoperative radiographs of patients managed by trapeziectomy and suspensionplasty in our department, and to assess the possibility of a surgical alternative-total joint replacement-based on the trapezium's height. We also wanted to determine whether radiological height was influenced by the radiological progression of the thumb OA. A single-center retrospective study based on available medical records was conducted. The patients included had TMC OA refractory to conservative treatment and were managed surgically by trapeziectomy and suspensionplasty between 2012 and 2018. Sixty-seven patients were eligible. Based on the Eaton-Littler classification of radiological TMC OA, our case series had 0% (n=0) stage I, 36% (n=24) stage II, 42% (n=28) stage III and 22% (n=15) stage IV findings. We measured the radiological trapezium height on AP and lateral views as described by Kapandji. These were 10.6mm and 10.8mm for stage II, 9.6mm and 8.9mm for stage III, 8.6mm and 7.8mm for stage IV, respectively. Eighty-six percent of patients had a trapezium height suitable for total joint replacement. The radiological height decreased significantly with the OA stage. At stage IV, the average height fell below the 8-mm threshold, compromising the surgical indication for total arthroplasty.

Multisensory components of rapid motor responses to fingertip loading.

Tactile and muscle afferents provide critical sensory information for grasp control, yet the contribution of each sensory system during online control has not been clearly identified. More precisely, it is unknown how these two sensory systems participate in online control of digit forces following perturbations to held objects. To address this issue, we investigated motor responses in the context of fingertip loading, which parallels the impact of perturbations to held objects on finger motion and fingerpad deformation, and characterized surface recordings of intrinsic (first dorsal interosseous, FDI) and extrinsic (flexor digitorum superficialis, FDS) hand muscles based on statistical modeling. We designed a series of experiments probing the effects of peripheral stimulation with or without anesthesia of the finger, and of task instructions. Loading of the fingertip generated a motor response in FDI at ~60 ms following the perturbation onset, which was only driven by muscle stretch, as the ring-block anesthesia reduced the gain of the response occurring later than 90 ms, leaving responses occurring before this time unaffected. In contrast, the motor response in FDS was independent of the lateral motion of the finger. This response started at ~90 ms on average and was immediately adjusted to task demands. Altogether these results highlight how a rapid integration of partially distinct sensorimotor circuits supports rapid motor responses to fingertip loading.NEW & NOTEWORTHY To grasp and manipulate objects, the brain uses touch signals related to skin deformation as well as sensory information about motion of the fingers encoded in muscle spindles. Here we investigated how these two sensory systems contribute to feedback responses to perturbation applied to the fingertip. We found distinct response components, suggesting that each sensory system engages separate sensorimotor circuits with distinct functions and latencies.

Effect of four-corner fusion with locking plate without bone graft on functional recovery of the wrist: New treatment guidelines.

We assessed the effect of four-corner intercarpal fusion with locking plate without bone graft on daily activities and pain in patients with stage II and III scapholunate advanced collapse and scaphoid nonunion. Twenty-one patients who underwent four-corner fusion with scaphoidectomy without bone graft were evaluated with the Disabilities of the Arm, Shoulder and Hand (QuickDASH) and Visual Analog Scale (VAS) pain scores before and 16 months after surgery. We also compared postoperative grip strength between the operated and the healthy side. A principal component analysis was used to establish the relationship between functional benefit, immobilization period and number of physiotherapy sessions. We compared our results with published data. VAS and QuickDASH scores improved significantly. Loss of strength was observed postoperatively. QuickDASH score improved the most with a short immobilization period. No significant difference was found relative to the literature for follow-up time, range of motion, grip strength and QuickDASH score. All patients had bone fusion after 1 year. Four-corner fusion with locking plate is a procedure that reduces pain and improves functional scores. Our results are equal to those reported in the literature with bone graft. The union rate seemed high despite the absence of bone graft but was only assessed by x rays. This study allowed us to establish a treatment guideline: a shorter immobilization leads to better recovery.

Difficult to treat osteoarticulars infections : Focus on Mycobacterial and Fungal infection.

Bone and joint infections are rare but often devastating. While bacteria are most commonly encountered organisms, mycobacteria and fungi are less frequent. Management of the latter is often more complex, especially in the presence of foreign material. We will increasingly be faced with mycobacterial and fungal bone infections, as medical conditions and newer therapeutics lead to more immunosuppression. In this article, we will review osteomyelitis, septic arthritis and peri-prosthetic joint infections related to mycobacteria and fungi.