Activity-Dependent Compensation at the Hip and Ankle at 8 Years After the Reconstruction of Isolated and Combined Posterior Cruciate Ligament Injuries.

BACKGROUND: After posterior cruciate ligament reconstruction (PCLR), functional deficits at the knee can persist. It remains unclear if neighboring joints compensate for the knee during demanding activities of daily living. PURPOSE: To assess long-term alterations in lower limb mechanics in patients after PCLR. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 28 patients who had undergone single-bundle unilateral isolated or combined PCLR performed stair navigation, squat, sit-to-stand, and stand-to-sit tasks at 8.2 ± 2.2 years after surgery. Motion capture and force plates were used to collect kinematic and kinetic data. Then, 3-dimensional hip, knee, and ankle kinematic data of the reconstructed limb were compared with those of the contralateral limb using statistical parametric mapping. RESULTS: Side-to-side differences at the knee were primarily found during upward-driven movements at 8 years after surgery. The reconstructed knee exhibited lower internal rotation during the initial loading phase of stair ascent versus the contralateral knee (P = .005). During the sit-to-stand task, higher flexion angles during the midcycle (P = .017) and lower external rotation angles (P = .049) were found in the reconstructed knee; sagittal knee (P = .001) and hip (P = .016) moments were lower in the reconstructed limb than the contralateral limb. In downward-driven movements, side-to-side differences were minimal at the knee but prominent at the ankle and hip: during stair descent, the reconstructed ankle exhibited lower dorsiflexion and lower external rotation during the midcycle versus the contralateral ankle (P = .006 and P = .040, respectively). Frontal hip moments in the reconstructed limb were higher than those in the contralateral limb during the stand-to-sit task (P = .010); during squats, sagittal hip angles in the reconstructed limb were higher than those in the contralateral limb (P < .001). CONCLUSION: Patients after PCLR exhibited compensations at the hip and ankle during downward-driven movements, such as stair descent, squats, and stand-to-sit. Conversely, residual long-term side-to-side differences at the knee were detected during upward-driven movements such as stair ascent and sit-to-stand. CLINICAL RELEVANCE: After PCLR, side-to-side differences in biomechanical function were activity-dependent and occurred either at the knee or neighboring joints. When referring to the contralateral limb to assess knee function in the reconstructed limb, concentric, upward-driven movements should be prioritized. Compensations at the hip and ankle during downward-driven movements lead to biases in long-term functional assessments.

Improved weight bearing during gait at 6 weeks post-surgery with an angle stable locking system after distal tibial fracture.

BACKGROUND: Functional recovery after intramedullary nailing of distal tibial fractures can be monitored using ipsilateral vertical ground reaction forces (vGRF), giving insight into recovery of patients' gait symmetry. Previous work compared patient cohorts to healthy controls, but it remains unclear if these metrics can identify treatment-based differences in return to function post-surgery. RESEARCH QUESTION: Is treatment of a distal tibial fracture with intramedullary nailing with an angle stable locking system (ASLS) associated with higher ipsilateral vGRF and improved symmetry compared to conventional intramedullary nailing at an early time point? METHODS: Thirty-nine patients treated with ASLS intramedullary nailing were retrospectively compared to thirty-nine patients with conventional locking. vGRFs were collected at 1, 6, 12, 26, and 52 weeks post-surgery during standing and gait. Discrete metrics of ipsilateral vGRF (maximal force, impulse) and asymmetry were compared between treatments at each time point. Time-scale comparisons of ipsilateral vGRF and lower limb asymmetry were additionally performed for gait trials. Mann-Whitney Test or a two-way analysis of variance tested discrete comparisons; statistical non-parametric mapping tested time-scale data between treatment groups. RESULTS: During gait, ASLS-treated patients applied more load on the operated limb (17-38% stance, p = 0.015) and consequently loaded limbs more symmetrically (8-37% stance, p = 0.008) during the loading response at 6 weeks post-surgery compared to conventional IM treatment. Discrete measures of symmetry at the same time point identified treatment-based differences in maximal force (p = 0.039) and impulse (p = 0.012), with ASLS-treated patients exhibiting more symmetry. No differences were identified in gait trials at later time points nor from all standing trials. SIGNIFICANCE: During the initial loading response of gait, increased ipsilateral vGRF and improved weightbearing symmetry were identified in ASLS patients at 6 weeks post-surgery compared to conventional IM nailing. Early and objective metrics of dynamic movement are suggested to identify treatment-based differences in functional recovery.

The Recovery of Weight-Bearing Symmetry After Total Hip Arthroplasty Is Activity-Dependent.

This study aimed to characterize ipsilateral loading and return to weight-bearing symmetry (WBS) in patients undergoing total hip arthroplasty (THA) during activities of daily living (ADLs) using instrumented insoles. A prospective study in 25 THA patients was performed, which included controlled pre- and postoperative follow-ups in a single rehabilitation center of an orthopedic department. Ipsilateral loading and WBS of ADLs were measured with insoles in THA patients and in a healthy control group of 25 participants. Measurements in the THA group were performed at 4 different visits: a week pre-THA, within a week post-THA, 3-6 weeks post-THA, and 6-12 weeks post-THA, whereas the healthy control group was measured once. ADLs included standing comfortably, standing evenly, walking, and sit-to-stand-to-sit (StS) transitions. All ADLs were analyzed using discrete methods, and walking included a time-scale analysis to provide temporal insights in the ipsilateral loading and WBS waveforms. THA patients only improved beyond their pre-surgery levels while standing comfortably (ipsilateral loading and WBS, p < 0.05) and during StS transitions (WBS, p < 0.05). Nevertheless, patients improved upon their ipsilateral loading and WBS deficits observed within a week post-surgery across all investigated ADLs. Ipsilateral loading and WBS of THA patients were comparable to healthy participants at 6-12 weeks post-THA, except for ipsilateral loading during walking (p < 0.05) at the initial and terminal double-leg support period of the stance phase. Taken together, insole measurements allow for the quantification of ipsilateral loading and WBS deficits during ADLs, identifying differences between pre- and postoperative periods, and differentiating THA patients from healthy participants. However, post-THA measurements that lack pre-surgery assessments may not be sensitive to identifying patient-specific improvements in ipsilateral loading and WBS. Moreover, StS transitions and earlier follow-up time points should be considered an important clinical metric of biomechanical recovery after THA.

Ground reaction forces and external hip joint moments predict in vivo hip contact forces during gait.

Younger patients increasingly receive total hip arthroplasty (THA) as therapy for end-stage osteoarthritis. To maintain the long-term success of THA in such patients, avoiding extremely high hip loads, i.e., in vivo hip contact force (HCF), is considered essential. However, in vivo HCFs are difficult to determine and their direct measurement is limited to instrumented joint implants. It remains unclear whether external measurements of ground reaction forces (GRFs), a non-invasive, markerless and clinic-friendly measure can estimate in vivo HCFs. Using data from eight patients with instrumented hip implants, this study determined whether GRF time series data, alone or combined with other scalar variables such as hip joint moments (HJMs) and lean muscle volume (LMV), could predict the resultant HCF (rHCF) impulse using a functional linear modeling approach. Overall, single GRF time series data did not predict in vivo rHCF impulses. However, when GRF time series data were combined with LMV of the gluteus medius or sagittal HJM using a functional linear modeling approach, the in vivo rHCF impulse could be predicted from external measures only. Accordingly, this approach can predict in vivo rHCF impulses, and thus provide patients with useful insight regarding their gait behavior to avoid hip joint overloading.

Intramuscular and intratendinous placenta-derived mesenchymal stromal-like cell treatment of a chronic quadriceps tendon rupture.

BACKGROUND: Quadriceps tendon ruptures (QTRs) are rare but debilitating injuries, often associated with chronic metabolic conditions or long-term steroid treatment. While the surgical treatment for acute QTRs is described thoroughly, no common strategy exists for the often frustrating treatment of chronic, reoccurring QTRs. The pro-angiogenic and immunomodulatory properties of placenta-derived adherent mesenchymal stromal-like (PLX-PAD) cells have been described to protect musculoskeletal tissues from inflammation and catabolic cytokine migration, yet little is known about the regenerative potential of PLX-PAD cells in repetitively damaged tendon tissue. CASE: We report the case of an 80-year-old male patient with a chronic three-time QTR of his right knee. The quadriceps tendon was reconstructed applying a conventional suture anchor repair procedure combined with a synthetic mesh augmentation and additional intramuscular and intratendineous PLX-PAD cell injections as an individualized treatment approach. No adverse events were reported, and excellent radiological and functional outcomes with a passive range of motion of 0/0/120° knee extension-flexion were observed at the 12 month follow-up. Gait analysis confirmed restoration of joint motion, including gait speed, deficit in step length, and knee extensor muscle strength (pre-surgery: 0.98 m/s, 40 cm, 42.4 ± 12.4 N; 9 months post-surgery: 1.07 m/s, 0 cm, 10.4 ± 18.9 N) as well as hyperextension throughout stance and late swing phases (pre-surgery: -11.2 ± 0.9°; 9 months post-surgery: -2.7 ± 1.6°). Postoperative lymphocyte and cytokine analyses from the patient's peripheral blood serum suggested a systemic short-term immunoregulatory reaction with postoperatively increased interleukin (IL)-6 (pre-surgery: 0.79 pg/mL; day 1: 139.97 pg/mL; day 5: 5.58 pg/mL; 9 months: 1.76 pg/mL) and IL-10 (pre-surgery: 0.9 pg/mL; day 1: 1.21 pg/ mL; day 5: 0.3 pg/mL; 9 months: 0.34 pg/mL) levels that decreased again over time. CONCLUSIONS: Herein, we demonstrate a successfully treated chronic QTR with a synergistic surgical and biological reconstructive treatment approach. This local add-on treatment with PLX-PAD cells may be considered in specific cases of chronic QTRs, not susceptible to traditional suture anchor procedures and which exhibit a high risk of treatment failure. Further scientific engagement is warranted to explore underlying immunomodulatory mechanisms of action behind PLX-PAD cell treatment for tendon injuries.

Does the Calcaneus Serve as Hypomochlion within the Lower Limb by a Myofascial Connection?-A Systematic Review.

(1) Background: Clinical approaches have depicted interconnectivity between the Achilles tendon and the plantar fascia. This concept has been applied in rehabilitation, prevention, and in conservative management plans, yet potential anatomical and histological connection is not fully understood. (2) Objective: To explore the possible explanation that the calcaneus acts as a hypomochlion. (3) Methods: 2 databases (Pubmed and Livivo) were searched and studies, including those that examined the relationship of the calcaneus to the Achilles tendon and plantar fascia and its biomechanical role. The included studies highlighted either the anatomical, histological, or biomechanical aspect of the lower limb. (4) Results: Seventeen studies were included. Some studies depicted an anatomical connection that slowly declines with age. Others mention a histological similarity and continuity via the paratenon, while a few papers have brought forward mechanical reasoning. (5) Conclusion: The concept of the calcaneus acting as a fulcrum in the lower limb can partially be supported by anatomical, histological, and biomechanical concepts. Despite the plethora of research, a comprehensive understanding is yet to be investigated. Further research exploring the precise interaction is necessary.

Gait Adaptations at 8 Years After Reconstruction of Unilateral Isolated and Combined Posterior Cruciate Ligament Injuries.

BACKGROUND: It remains unclear how posterior cruciate ligament (PCL) reconstruction influences long-term lower extremity joint biomechanics. PURPOSE: To determine whether patients who underwent PCL reconstruction exhibited long-term alterations in lower limb gait mechanics. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 26 patients underwent gait analyses at 8.2 ± 2.6 years after primary unilateral PCL reconstruction. Sex- and age-matched healthy controls were analyzed for comparison. Gait data were collected using motion capture and force plates. Hip, knee, and ankle angles and moments were compared during initial contact, early stance, and late stance for the reconstructed and uninjured contralateral limbs of patients who underwent PCL reconstruction (PCL group) as well as the limbs of healthy control participants (CON group). RESULTS: No side-to-side kinematic differences were noted between the reconstructed and contralateral limbs of the PCL group; some trivial differences were noted in knee and hip moments. However, major differences between the PCL and CON groups occurred at the knee. Reconstructed and contralateral limbs of the PCL group exhibited larger knee flexion angles during initial contact (Δ = 7.0° [P < .001] and Δ = 6.9° [P < .001], respectively), early stance (Δ = 5.8° [P = .003] and Δ = 6.7° [P < .001], respectively), and late stance (Δ = 7.9° [P < .001] and Δ = 8.0° [P < .001], respectively) compared with the CON group. During early stance, contralateral limbs of the PCL group displayed larger knee flexion moments (Δ = 0.20 N·m/kg; P = .014) compared with the CON group, and both reconstructed (Δ = 0.05 N·m/kg; P = .027) and contralateral (Δ = 0.07 N·m/kg; P = .001) limbs of the PCL group exhibited larger knee external rotation moments compared with the CON group. During late stance, reconstructed and contralateral limbs of the PCL group exhibited smaller knee extension moments (Δ = 0.24 N·m/kg [P < .001] and Δ = 0.26 N·m/kg [P < .001], respectively) and knee internal rotation moments (Δ = 0.06 N·m/kg [P < .001] and Δ = 0.06 N·m/kg [P < .001], respectively) compared with the CON group. No discrepancies were observed at the hip; minimal differences were noted in sagittal-plane ankle mechanics. CONCLUSION: Patients who underwent PCL reconstruction generally exhibited bilateral gait symmetry at 8 years after surgery. However, they exhibited important biomechanical deviations in both knees compared with healthy controls. These modifications likely reflect adaptive gait strategies to protect the PCL after reconstruction. CLINICAL RELEVANCE: Long-term follow-up analyses of patients who underwent PCL reconstruction should not use the uninjured contralateral limb as a "healthy" reference, as it also exhibits mechanical differences compared with controls. Results could inform the development of neuromuscular and strength training programs targeting the restoration of knee biomechanics similar to healthy controls to prevent early-onset degeneration that is frequently associated with altered biomechanics.

Quantifying Asymmetry in Gait: The Weighted Universal Symmetry Index to Evaluate 3D Ground Reaction Forces.

Though gait asymmetry is used as a metric of functional recovery in clinical rehabilitation, there is no consensus on an ideal method for its evaluation. Various methods have been proposed to analyze single bilateral signals but are limited in scope, as they can often use only positive signals or discrete values extracted from time-scale data as input. By defining five symmetry axioms, a framework for benchmarking existing methods was established and a new method was described here for the first time: the weighted universal symmetry index (wUSI), which overcomes limitations of other methods. Both existing methods and the wUSI were mathematically compared to each other and in respect to their ability to fulfill the proposed symmetry axioms. Eligible methods that fulfilled these axioms were then applied using both discrete and continuous approaches to ground reaction force (GRF) data collected from healthy gait, both with and without artificially induced asymmetry using a single instrumented elbow crutch. The wUSI with a continuous approach was the only symmetry method capable of identifying GRF asymmetry differences in different walking conditions in all three planes of motion. When used with a continuous approach, the wUSI method was able to detect asymmetries while avoiding artificial inflation, a common problem reported in other methods. In conclusion, the wUSI is proposed as a universal method to quantify three-dimensional GRF asymmetries, which may also be expanded to other biomechanical signals.

Muscle Fascicles Exhibit Limited Passive Elongation Throughout the Rehabilitation of Achilles Tendon Rupture After Percutaneous Repair.

Achilles tendon rupture (ATR) results in long-term functional and structural deficits, characterized by reduced ankle mobility and plantarflexor muscle atrophy. However, it remains unclear how such functional impairments develop after surgical repair. While it is known that this injury negatively affects the tendon's function, to date, limited work has focused on the short-term effect of ATR on the structure of the muscles in series. The aim of this study was to characterize changes in medial gastrocnemius architecture and its response to passive lengthening during the post-surgical rehabilitative period following ATR. Both injured and contralateral limbs from 10 subjects (1 female, BMI: 27.2 ± 3.9 kg/m2; age: 46 ± 10 years) with acute, unilateral ATR were assessed at 8, 12, and 16 weeks after percutaneous surgical repair. To characterize the component tissues of the muscle-tendon unit, resting medial gastrocnemius muscle thickness, fascicle length, and pennation angle were determined from ultrasound images with the ankle in both maximal plantarflexion and dorsiflexion. The ankle range of motion (ROM) was determined using motion capture; combined ultrasound and motion capture determined the relative displacement of the musculotendinous junction (MTJ) of the AT with the medial gastrocnemius. The ATR-injured gastrocnemius muscle consistently exhibited lower thickness, regardless of time point and ankle angle. Maximal ankle plantarflexion angles and corresponding fascicle lengths were lower on the injured ankle compared to the contralateral throughout rehabilitation. When normalized to the overall ankle ROM, both injured fascicles and MTJ displacement exhibited a comparably lower change in length when the ankle was passively rotated. These results indicate that when both ankles are passively exposed to the same ROM following ATR surgery, both ipsilateral Achilles tendon and gastrocnemius muscle fascicles exhibit limited lengthening compared to the contralateral MTU tissues. This appears to be consistent throughout the rehabilitation of gait, suggesting that current post-operative rehabilitative exercises do not appear to induce muscle adaptations in the affected MTU.

Validation of a Novel Device for the Knee Monitoring of Orthopaedic Patients.

Fast-track surgery is becoming increasingly popular, whereas the monitoring of postoperative rehabilitation remains a matter of considerable debate. The aim of this study was to validate a newly developed wearable system intended to monitor knee function and mobility. A sensor system with a nine-degree-of-freedom (DOF) inertial measurement unit (IMU) was developed. Thirteen healthy volunteers performed five 10-meter walking trials with simultaneous sensor and motion capture data collection. The obtained kinematic waveforms were analysed using root mean square error (RMSE) and correlation coefficient (CC) calculations. The Bland-Altman method was used for the agreement of discrete parameters consisting of peak knee angles between systems. To test the reliability, 10 other subjects with sensors walked a track of 10 metres on two consecutive days. The Pearson CC was excellent for the walking data set between both systems (r = 0.96) and very good (r = 0.95) within the sensor system. The RMSE during walking was 5.17° between systems and 6.82° within sensor measurements. No significant differences were detected between the mean values observed, except for the extension angle during the stance phase (E1). Similar results were obtained for the repeatability test. Intra-class correlation coefficients (ICCs) between systems were excellent for the flexion angle during the swing phase (F1); good for the flexion angle during the stance phase (F2) and the re-extension angle, which was calculated by subtracting the extension angle at swing phase (E2) from F2; and moderate for the extension angle during the stance phase (E1), E2 and the range of motion (ROM). ICCs within the sensor measurements were good for the ROM, F2 and re-extension, and moderate for F1, E1 and E2. The study shows that the novel sensor system can record sagittal knee kinematics during walking in healthy subjects comparable to those of a motion capture system.

Dynamics of postural control in individuals with ankle instability: Effect of visual input and orthotic use.

The present study investigated the effect of visual deprivation and the use of an ankle orthosis on the dynamics of center of pressure (COP) trajectories during unilateral stance in individuals with ankle instability (AI). Sixteen individuals with AI and nine healthy individuals performed four trials of 30s unilateral stance on a force platform with 1) eyes open wearing no orthosis, 2) eyes closed wearing no orthosis, 3) eyes open wearing orthosis, and 4) eyes closed wearing orthosis. The anterior-posterior and mediolateral COP trajectory were extracted. Regularity was quantified by sample entropy, dimensionality was quantified by correlation dimension and level of time dependency was quantified by entropic half-life. The AI individuals had lower sample entropy and longer entropic half-life in their COP trajectories. The effect of visual deprivation did not differ between groups. Wearing an ankle orthosis increased the sample entropy in the anterior-posterior direction and decreased the correlation dimension in the mediolateral direction for the AI group only. Individuals with AI have higher COP trajectory regularity and higher level of time dependency compared to healthy individuals. Additionally, individuals with AI do not alter the dynamics of their postural control during unilateral stance with visual deprivation compared to healthy individuals. This suggests that alterations in visual or somatosensory information differently affect the executed postural movement pattern. Finally, wearing an orthosis significantly alters the COP dynamics of individuals with AI.

The Effect of Ankle Bracing on Kinematics in Simulated Sprain and Drop Landings: A Double-Blind, Placebo-Controlled Study.

BACKGROUND: The efficacy of external ankle braces to protect against sudden inversion sprain has yet to be determined while taking into account the possible placebo effect of brace application. PURPOSE: To assess the protective effect of an external ankle brace on ankle kinematics during simulated inversion sprain and single-legged drop landings among individuals with a history of unilateral lateral ankle sprain. HYPOTHESIS: The primary hypothesis was that active and placebo external braces would reduce inversion angle during simulated inversion sprain. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen participants with ankle instability and previous sprain performed single-legged drop landings and sudden inversion tilt perturbations. Kinematics of the affected limb were assessed in 3 conditions (active bracing, passive placebo bracing, and unbraced) across 2 measurement days. Participators and investigators were blinded to the brace type tested. The effect of bracing on kinematics was assessed with repeated measures analysis of variance with statistical parametric mapping, with post hoc tests performed for significant interactions. RESULTS: Only active bracing reduced inversion angles during a sudden ankle inversion when compared with the unbraced condition. This reduction was apparent between 65 and 140 milliseconds after the initial fall. No significant differences in inversion angle were found between the passive placebo brace and unbraced conditions during sudden ankle inversion. Furthermore, no significant differences were found among all tested conditions in the sagittal plane kinematics at the knee and ankle. CONCLUSION: During an inversion sprain, only the actively protecting ankle brace limited inversion angles among participants. These results do not indicate a placebo effect of external bracing for patients with ankle instability and a history of unilateral ankle sprain. Furthermore, sagittal plane knee kinematics appear to remain unaffected by bracing during single-legged landing, owing to the limited effects of bracing on sagittal ankle kinematics. These results highlight the role of brace design on biomechanical function during sports-related and injury-prone movements. CLINICAL RELEVANCE: Athletes prone to reinjury after lateral ankle sprain may benefit from brace designs that allow for full sagittal range of motion but restrict only frontal plane motion.

Alterations in structure of the muscle-tendon unit and gait pattern after percutaneous repair of Achilles tendon rupture with the Dresden instrument.

BACKGROUND: Functional deficits after Achilles tendon (AT) ruptures are observed. The relationship between musculotendinous structural alterations and functional outcome is not clear. METHODS: Kinematic analyses (level walking, stair climbing), patient-reported outcome measures (PROMs), calf atrophy (maximum calf circumference (MCC)), and AT length were evaluated in patients after percutaneous AT repair with the Dresden instrument (n=20min. FOLLOW-UP: 24 months). RESULTS: Patients achieved good results in PROMs. However, MCC decreased significantly and AT length increased significantly postoperatively. Side-to-side MCC differences over 2cm resulted in significantly lower PROMs. AT lengthening correlated with increased dorsiflexion and decreased plantarflexion. CONCLUSION: Calf atrophy and AT lengthening after minimally invasive AT repair resulted in inferior ankle kinematics and PROMs.

Functional outcome and complication rate after percutaneous suture of fresh Achilles tendon ruptures with the Dresden instrument.

BACKGROUND: The aim of this study was to evaluate the outcome of patients with a rupture of the Achilles tendon (ATR) treated percutaneously with the Dresden instrument in the hands of surgeons others than its inventors. MATERIALS AND METHODS: 118 patients (FU rate: 77.1%) with an acute ATR treated with the Dresden instrument were retrospectively evaluated. The following data were evaluated: pain intensity, functional limitation, Hannover score, Achilles tendon total rupture score (ATRS), AOFAS ankle-hindfoot score, Tegner activity score, complications, maximum calf circumference (MCC) on both sides, and the Matles test for tendon lengthening. The effect of the time point of the surgery after trauma was examined. RESULTS: Hannover scores and ATRSs were good; AOFAS scores were excellent. Almost all patients returned to sporting activities postoperatively, and 66.1% were able to return to their previous level. The Tegner activity score revealed a slight posttraumatic decrease (p = 0.009) in the level of physical activity overall (pre-injury: 5.37 ± 0.15; postoperatively: 4.77 ± 0.15). The re-rupture rate was 2%. No sural nerve lesions and no infections were reported. Even after 3 years, there was still a difference in MCC that was correlated with inferior clinical score and AT lengthening. Patients treated within the first 2 days after ATR showed inferior clinical outcomes in terms of AOFAS score, ATRS, and functional limitations. CONCLUSIONS: Percutaneous ATR suture with the Dresden instrument is a safe and reliable method. Low complication and re-rupture rates, good clinical results, and a high rate of return to play support this fact. The time point of the operation may influence the outcome.

Immunomodulatory placental-expanded, mesenchymal stromal cells improve muscle function following hip arthroplasty.

BACKGROUND: No regenerative approach has thus far been shown to be effective in skeletal muscle injuries, despite their high frequency and associated functional deficits. We sought to address surgical trauma-related muscle injuries using local intraoperative application of allogeneic placenta-derived, mesenchymal-like adherent cells (PLX-PAD), using hip arthroplasty as a standardized injury model, because of the high regenerative and immunomodulatory potency of this cell type. METHODS: Our pilot phase I/IIa study was prospective, randomized, double blind, and placebo-controlled. Twenty patients undergoing hip arthroplasty via a direct lateral approach received an injection of 3.0 × 108 (300 M, n = 6) or 1.5 × 108 (150 M, n = 7) PLX-PAD or a placebo (n = 7) into the injured gluteus medius muscles. RESULTS: We did not observe any relevant PLX-PAD-related adverse events at the 2-year follow-up. Improved gluteus medius strength was noted as early as Week 6 in the treatment-groups. Surprisingly, until Week 26, the low-dose group outperformed the high-dose group and reached significantly improved strength compared with placebo [150 M vs. placebo: P = 0.007 (baseline adjusted; 95% confidence interval 7.6, 43.9); preoperative baseline values mean ± SE: placebo: 24.4 ± 6.7 Nm, 150 M: 27.3 ± 5.6 Nm], mirrored by an increase in muscle volume [150 M vs. placebo: P = 0.004 (baseline adjusted; 95% confidence interval 6.0, 30.0); preoperative baseline values GM volume: placebo: 211.9 ± 15.3 cm3 , 150 M: 237.4 ± 27.2 cm3 ]. Histology indicated accelerated healing after cell therapy. Biomarker studies revealed that low-dose treatment reduced the surgery-related immunological stress reaction more than high-dose treatment (exemplarily: CD16+ NK cells: Day 1 P = 0.06 vs. placebo, P = 0.07 vs. 150 M; CD4+ T-cells: Day 1 P = 0.04 vs. placebo, P = 0.08 vs. 150 M). Signs of late-onset immune reactivity after high-dose treatment corresponded to reduced functional improvement. CONCLUSIONS: Allogeneic PLX-PAD therapy improved strength and volume of injured skeletal muscle with a reasonable safety profile. Outcomes could be positively correlated with the modulation of early postoperative stress-related immunological reactions.

Short-term functional assessment of gait, plantarflexor strength, and tendon properties after Achilles tendon rupture.

BACKGROUND: Although early functional rehabilitation (EFR) has been suggested to yield rapid functional recovery after Achilles tendon rupture (ATR) compared to conventional rehabilitation (CR), most quantitative assessments occur long after rehabilitation has been completed. Few data exist regarding the short-term functional gains during the healing period post-ATR. It remains unclear if EFR allows for an objectively faster return to function. The aim of this study was to examine EFR's effect on gait, plantarflexor strength, and tendon properties in early post-operative follow-ups. METHODS: Fourteen patients received either EFR (n = 6) or CR (n = 8) after percutaneous ATR repair. Functional gait analysis, maximal voluntary isometric contractions (MVICs), and Achilles tendon properties were assessed at 8 and 12 weeks post-op. RESULTS: Comparison of EFR against CR yielded no statistically significant differences in ankle kinematics or kinetics, Achilles tendon properties or MVICs on the injured (INJ) ankle at either time point. During gait, only CR patients demonstrated significantly lower plantarflexion moments on INJ at 8 weeks (0.817 ±â€¯0.151 N·m/kg vs. 1.172 ±â€¯0.177 N·m/kg, p = 0.002). All patients exhibited deficits in plantarflexor moment at 8 weeks and eversion moment at 12 weeks on INJ during gait that had effect sizes of note when compared to CON. SIGNIFICANCE: ATR patients, regardless of rehabilitation, exhibit deficits in gait, AT properties, and single-limb strength at 8 weeks. Though AT properties and single-limb plantarflexor isometric strength remain at a deficit at 12 weeks, bipedal plantarflexion moments are comparable between INJ and CON. Though effect size calculations suggested clinically significant differences, clear benefits of EFR compared to CR were not found.

Automatic initial contact detection during overground walking for clinical use.

The division of gait into cycles is crucial for identifying deficits in locomotion, particularly to monitor disease progression or rehabilitative recovery. Initial contact (IC) events are often used to separate movement into repetitive cycles yet automatic methods for IC identification in pathological gait are limited in both number and capacity. The aim of this work was to develop a more precise algorithm in IC detection. A projected heel markers distance (PHMD) algorithm is presented here and compared for accuracy to the high pass algorithm (HPA) in IC identification. Kinematic gait data from two clinical cohorts were analyzed and processed automatically for IC detection: (1) unilateral total hip arthroplasty (THA) patients (n=27) and (2) cerebral palsy pediatric (CPP) patients (n=20). IC events determined by the two algorithms were benchmarked against the IC events detected manually and from force plates. The PHMD method detected 96.6% IC events in THA patients and 99.1% in CPP patients with an average error of 5.3 ms and 18.4 ms. The HPA method detected 99.1% IC events in THA patients and 97.3% IC events in CPP patients, with an average error of 57.5 ms and 10.2 ms. PHMD identified no superfluous IC events, whereas 51.5% of all THA IC and 47.6% of CPP IC were superfluous events requiring manual deletion with HPA. With the superior comparison against the current gold standard, the PHMD algorithm appears valid for a wide spectrum of clinical data sets and allows for precise, fully automatic processing of kinematic gait data without additional sensors, triggers, or force plates.