Onychectomized cats (Felis catus) with inappropriate elimination behaviors or aggression may be responding to painful paw pathology, even several years after the initial onychectomy. The objectives of this study were to evaluate the onychectomized toes of this population of cats for pain (thorough physical examination and/or buprenorphine trial), pathological changes (using high-resolution radiographs) and response to tenectomy in those with hyperflexion of the proximal interphalangeal joint.
Cats in this study were previously onychectomized and exhibited inappropriate behaviors (inappropriate elimination, biting), exhibited pain associated with the onychectomy site or had behavioral improvements when put on a 2-week buprenorphine trial. A detailed history was obtained, including verification of proper litter box placement and management. Physical examinations included a close analysis of the onychectomized digits for resistance to extension and pain on palpation. Only cats with a normal urinalysis were included in the study. High-resolution radiographic imaging was performed on all study cats. A total flexor tenectomy was performed on cats with hyperflexion of the proximal interphalangeal joints.
All 42 cats included in the study benefited from total flexor tenectomy surgery. Two cats remained biters, even after a long course of analgesic medication. All cats walked more comfortably post-tenectomy surgery.
Onychectomy can lead to pain, inappropriate elimination and aggressive behavior. The presented salvage tenectomy procedure can alleviate or eliminate inappropriate behaviors by reducing the pain from the original onychectomy.

UNASSIGNED: We aimed to compare whether the visualisation provided by arthroscopic hyperflexion and Figure 4 has an effect on femoral tunnel placement in patients undergoing single bundle Anterior Cruciate Ligament Reconstruction (ACLR).
UNASSIGNED: We retrospectively evaluated 93 patients who underwent single-band ACLR for Anterior Cruciate Ligament (ACL) injury between 2016 and 2019. Eighty patients met the inclusion criteria with a minimum follow-up of 12 months. We divided the patients into Group 1 (figure 4) and Group 2 (hyperflexion). We analysed the demographic, radiological and functional outcomes of the patients. The functional Lysholm score, operative time, radiological Quadrant method (% proximal-distal and % anterior-posterior) measurements, tunnel lengths, axial and coronal plane angles, and iatrogenic chondral injury in the medial femoral condyle were evaluated.
UNASSIGNED: Iatrogenic chondral injury developed in the medial femoral condyle in a total of seven patients in both groups: one patient in group 1 (Figure 4) and six patients in group 2 (Hyperflexion). Although statistically insignificant, iatrogenic medial femoral condyle damage was less in group 1. The statistical analysis between surgical operation time (p = 0.046) and tunnel lengths (p = 0.042) was significant.
UNASSIGNED: The position of figure 4 provides visualisation of lateral intercondylar notch better than hyperflexion. In the reaming stage, the medial femoral condyle is less damaged in group 1 (Figure 4). In ACLR, which has a long learning curve, short surgery time is seen as an important advantage for surgeons who have just started doing ACLR. We think that it can be used as an alternative method to hyperflexion in the learning process and maybe shorten the learning curve process.

Flexion of the horse\'s head and neck during dressage riding reduces the pharyngeal lumen with the risk of increased upper airway resistance and upper airway obstructions. According to the Fédération Equestre Internationale, hyperflexion is achieved through force, whereas the position low-deep-round is nonforced. The objectives of this study were to evaluate (1) applied rein tension and (2) dynamic structural disorders in the upper airways in dressage horses in different gaits and different head-neck positions (HNPs). Overground endoscopy (OGE) and rein tension were evaluated in 13 clinically healthy and high-performance Warmblood dressage horses while being ridden in a standardized program comprised of four different gaits (halt, walk, trot, and canter) and in four HNPs (unrestrained, competition frame, hyperflexion, and low-deep-round). All included horses were able to achieve the desired HNPs. The HNP low-deep-round showed significantly lower rein tension than competition frame (P < .001) and hyperflexion (P < .001). An association was found between dynamic structural disorders in the upper airway tract evaluated by OGE and head-neck flexion, but this association was not linked to the degree of flexion. The HNP hyperflexion was neither associated with greater rein tension nor severe dynamic structural disorders than the HNP competition frame. This study confirms that low-deep-round is a nonforced position, in contrast to hyperflexion. Further studies are needed to evaluate whether dynamic structural disorders are a result of flexion or if the degree of flexion has an impact.

Mallet injury is associated with variable degrees of extensor hallucis longus tendon tearing, ultimately leading to the well-known mallet toe deformity; this entity, commonly described at the lesser toes and fingers, has rarely been reported at the hallux. We present a surgically proven case of mallet hallux injury with radiographic and magnetic resonance imaging assessment and review the literature, including clinical and radiological findings, along with basic treatment concepts.

Cervical bilateral facet dislocations are among the most devastating spine injuries in terms of likelihood of severe neurological sequelae. More than half of patients with tetraparesis had sustained some form of bilateral facet fracture dislocation. They can occur at any level of the sub-axial cervical spine, but predominate between C5 and C7. The mechanism of these injuries has long been thought to be forceful flexion of the chin towards the chest. This \"hyperflexion\" hypothesis comports well with intuition and it has become dogma in the clinical literature. However, biomechanical studies of the human cervical spine have had little success in producing this clinically common and devastating injury in a flexion mode of loading.
The purpose of this manuscript is to review the clinical and engineering literature on the biomechanics of bilateral facet dislocations and to describe the mechanical reasons for the causal role of compression, and the limited role of head flexion, in producing bilateral facet dislocations.
Bilateral facet dislocations have only been produced in experiments where compression is the primary loading mode. To date, no biomechanical study has produced bilateral facet dislocations in a whole spine by bending. Yet the notion that it is primarily a hyper-flexion injury persists in the clinical literature.
Compression and compressive buckling are the primary causes of bilateral facet dislocations. It is important to stop using the hyper-flexion nomenclature to describe this class of cervical spines injuries because it may have a detrimental effect on designs for injury prevention.

BACKGROUND: Debate surrounds the use of high rein tension for obtaining different head and neck positions in the training of sport horses on account of possible welfare issues.
OBJECTIVE: To compare auxiliary rein tension in two methods (Draw Reins and Concord Leader) for obtaining a standardised head and neck position on a hard and a soft surface.
METHODS: Intervention study.
METHODS: Left and right rein tensions were measured in 11 base-level trained client-owned sport horses (mean age ± s.d.; 10 ± 3.2 years) exercised in-hand with, in a random order, conventional draw reins or the newly developed Concord Leader in a standardised head and neck position. Rein tension was measured using a calibrated device operating at 10 Hz during six runs of 15 s in a straight line for each training method on both a hard and a soft surface. A linear mixed model and grouped logistic regression analysis were applied to compare the two methods (P<0.05).
RESULTS: The odds of a tension of 0 N were lower with draw reins than with the Concord Leader. The rein tension (mean sum of the force applied, in N) of the draw reins was 13.8 times higher than that of the Concord Leader.
UNASSIGNED: This study was performed on horses exercised in-hand; however, these auxiliary aids are normally used when lungeing. Possible redirection of rein tension towards the poll was not measured.
CONCLUSIONS: We showed that when using the Concord Leader a similar head and neck position is achieved with a much lower rein tension than with the draw reins and, more importantly, with a much greater likelihood of 0 N. It is unnecessary to use high auxiliary rein tension to obtain a standard, flexed head and neck position.

Among veterinary surgeons, interest has recently increased in the role of the horse\'s neck as a causative factor in complex locomotor disturbances. Specifically, controversy surrounds the trend for the head to be carried behind the vertical (BHV) in contravention of Fédération Equestre Internationale (FEI) rules. The aim of this study was to determine whether the head angulation of elite dressage horses has changed over the last 25 years, and whether head angulation correlates with the competition score awarded. Head angle was measured from videos recorded during the Grand Prix test at the 1992 Olympic Games and the 2008 World Cup Final, during collected canter (CC), collected trot (CT), passage (Pa), and piaffe (Pi). Head angulations were BHV in CC and CT in both 1992 and 2008. The likelihood of being BHV during Pa or Pi was significantly greater in 2008 than in 1992 (P <0.05). Higher scores correlated significantly with head positions that were further BHV during Pi in 2008 (P <0.05). Head angulations were orientated BHV in all paces in 2008, whereas in 1992 this was only the case for CT and CC. These findings support the hypothesis that, in recent years, FEI dressage judges have not penalised horses for a head position BHV. The findings also support the need for further studies of the effects of head and neck position on the health of horses.

The Knowledge of muscle activity in common head-neck positions (HNPs) is a necessary precondition for making judgements on HNPs. The aim of the study was to record the surface electromyography activities of important muscles of the horse\'s neck in various HNPs. The electrical activities of the m. splenius, brachiocephalicus and trapezius were recorded on both sides. Five horses, both with and without a rider, were examined in all three gaits on both hands in three different HNPs: a \'free\' position, a \'gathered\' (head higher, neck more flexed) position with the noseline in front of the vertical and a \'hyperflexed\' position. Averages of ten consecutive gait cycles in each HNP were evaluated and compared by standard statistical methods. No difference between ridden and unridden horses could be detected. The m. brachiocephalicus was in the hyperflexed position in all gaits significantly (p < 0.01) more active than in the gathered and free position, which were not significantly different. By contrast, the m. splenius was in the hyperflexed position less active than in the free position (p < 0.02), in which it always showed the highest activity. In walking, the muscle activities in the free and gathered positions deviated significantly (p < 0.01). The m. trapezius was in the hyperflexed posture during walking significantly less active than in the free (p < 0.01) and gathered (p < 0.01) positions with the strongest activities in the free position. Again, the free and gathered positions differed significantly (p < 0.01). In trot, the same pattern occured, although the gathered and hyperflexed positions did not differ significantly. In the canter, the activities of the m. trapezius showed no differences between HNPs. In HNPs with the noseline in front of the vertical, the muscles of the topline (m. splenius, m. trapezius) are activated and trained. In the hyperflexed position, however, a major muscle of the lower topline (m. brachiocephalicus) is activated and trained.

The capacity to perform certain activities is frequently compromised after total knee arthroplasty (TKA) due to a functional decline resulting from decreased range of motion and a diminished ability to kneel. In this manuscript, the current biomechanical understanding of hyperflexion and kneeling before and after TKA will be discussed. Patellofemoral and tibiofemoral joint contact area, contact pressure, and kinematics were evaluated in cadaveric studies using a Tekscan pressure measuring system and Microscribe. Testing was performed on intact knees and following cruciate retaining and posterior stabilized TKA at knee flexion angles of 90°, 105°, 120°, and 135°. Three loading conditions were used to simulate squatting, double stance kneeling, and single stance kneeling. Following TKA with double stance kneeling, patellofemoral contact areas did not increase significantly at high knee flexion angle (135°). Kneeling resulted in tibial posterior translation and external rotation at all flexion angles. Moving from double to single stance kneeling tended to increase pressures in the cruciate retaining group, but decreased pressures in the posterior stabilized group. The cruciate retaining group had significantly larger contact areas than the posterior stabilized group, although no significant differences in pressures were observed comparing the two TKA designs (p < 0.05). If greater than 120° of postoperative knee range of motion can be achieved following TKA, then kneeling may be performed with less risk in the patellofemoral joint than was previously believed to be the case. However, kneeling may increase the likelihood of damage to cartilage and menisci in intact knees and after TKA increases in tibiofemoral contact area and pressures may lead to polyethyelene wear if performed on a chronic, repetitive basis.

The effects of hyperflexion on the welfare of dressage horses have been debated. This study aimed to investigate acute stress responses of dressage horses ridden in three different Head-and-Neck-positions (HNPs). Fifteen dressage horses were ridden by their usual rider in a standardised 10-min dressage programme in either the competition frame (CF), hyperflexion (\"Low-Deep-and-Round\"; LDR) or a looser frame (LF) in a balanced order on three separate test days. Heart rate (HR), heart rate variability parameters (HRV), behaviour and rein tension were recorded during the test. Salivary cortisol concentrations were measured 60 min before and 0, 5, 15 and 30 min after the test. Rein tension was significantly lower in LF and did not differ between CF and LDR; however approx. 15% of recordings in CF and LDR were above the sensor detection limit of 5 kg. The horses had significantly higher cortisol concentrations directly after LDR compared to LF. In addition, the horses showed more distinctive head movements, including head waving, during LDR. There were no significant treatment effects on HR and HRV. In conclusion, the results indicate that LDR may be more stressful to these horses during riding.