Hypoesthesia after anterior cruciate ligament reconstruction: The relationship between proprioception and vibration perception deficits in individuals greater than one year post-surgery.

BACKGROUND: While surgical reconstruction restores mechanical stability following anterior cruciate ligament (ACL) rupture, many experience early-onset osteoarthritis despite surgery. Neurophysiological changes are hypothesized to contribute to knee osteoarthritis progression. Proprioceptive deficits have been reported following ACL injury/reconstruction; however, vibration perception threshold (VPT) has been less studied. This study explored relationships between pain, VPT, proprioception, function, and strength following ACL-reconstruction. METHODS: Twenty individuals (27 ±â€¯6 years; 10 males) (standard deviation) status-post ACL-reconstruction were compared with a control group. Measurements included VPT, proprioception (threshold to detect passive movement), pain, function (Knee Outcome Survey (KOS)) and isometric quadriceps strength. Group differences were assessed using Mann-Whitney U tests, side-to-side differences with Wilcoxon Signed Rank tests, and associations evaluated using Spearman correlations. RESULTS: The ACL-reconstruction group had minor functional deficits (15 ±â€¯11%) and resting pain (1.8 ±â€¯1.7). Impaired VPT and proprioception (hypoesthesia) were demonstrated on surgical compared to contralateral and control limbs (p ≤ 0.008). Proprioception was significantly different between contralateral and control knees, but not VPT. Surgical knee proprioceptive deficits and VPT deficits were positively correlated (ρ = 0.462, p = 0.047) but not in controls (ρ = -0.042, p = 0.862). Strength was negatively correlated to pain (ρ = -0.589; p = 0.006), but not to KOS scores, proprioception or VPT (p ≥ 0.099). CONCLUSION: Proprioceptive deficits following ACL injury have been ascribed to loss of afferent input from the torn ligament. Alternatively, multi-modality as well as contralateral sensory deficits suggest a spinal/supraspinal source of neurophysiological findings which may predispose to early osteoarthritis. LEVEL OF EVIDENCE: III.

Inter-joint coordination of kinematics and kinetics before and after total hip arthroplasty compared to asymptomatic subjects.

While differences in joint kinematics and kinetics between control subjects and patients before and after total hip arthroplasty (THA) has often been studied, inter-joint coordination has not been fully characterized. We hypothesized that in patients undergoing THA, inter-joint coordination (i) is different from control subjects before surgery, (ii) changes from pre-operative to post-operative, and (iii) remains different from control subjects after surgery. Seventy-eight subjects underwent gait analysis before and ∼1 year after primary unilateral THA. 109 control subjects were age, sex, and BMI matched to the THA group. We selected a representative trial at each subjects' self-selected walking speed from a motion analysis data repository. To assess kinematic coordination, we constructed sagittal plane hip-knee angle cyclograms, and calculated total, stance, and swing phase plot area (deg2). To assess kinetic coordination, we calculated the support moment (MS, %wt ∗ ht), the time-integral of support moment (MS impulse, %wt ∗ ht ∗ t), and the relative contribution of each joint to MS impulse (%Hip, %Knee, %Ankle). We used t-tests to compare groups. Total and swing-phase cyclogram area was smaller preoperatively, but improved to control values after THA. Swing-phase area was smaller than control values after THA. MS impulse was larger in THA subjects than controls both before and after surgery. While, the relative contribution of the hip to MS impulse was not different from control values, the contributions of the knee and ankle were smaller. Inter-joint coordination, as measured by hip-knee angle cyclograms and MS impulse, may be used to distinguish differences in gait mechanics between osteoarthritis and THA. Future work focusing on coordination among joints may be needed to fully restore gait function.

Preoperative gait mechanics predict clinical response to total hip arthroplasty.

Some patients do not have an adequate clinical response to total hip arthroplasty (THA) for reasons that are not fully understood. Identifying modifiable factors that are associated with nonresponse could lead to new ways to identify and treat potential nonresponders. This study investigated whether any preoperative gait characteristics were associated with THA clinical response, and whether or not there were corresponding postoperative gait differences in THA nonresponders compared to responders. A secondary analysis was conducted of 124 subjects (age 61 ± 10 years; 64 female/60 male), evaluated before and 1 year after primary unilateral THA, using quantitative gait analysis and Harris Hip Scores (HHS). Responders and nonresponders were identified using the OMERACT-OARSI responder criteria, modified for use with the HHS. Pre- and postoperative dynamic sagittal plane range of motion (ROM) and 3D peak external moments were compared, for responders and nonresponders, using t-tests and logistic regression. 11.3% of subjects were nonresponders. Before surgery, the ROM was 26% higher for nonresponders than responders, but the peak external rotation moment was 30% lower (p = 0.003-0.043). Preoperative gait and HHS predicted response with a sensitivity of 71.4% and a specificity of 99.1%. There were persistent postoperative deficits in the peak external rotation moment in nonresponders compared to responders (p = 0.028). This study showed that gait analysis, where available, can augment clinical scores in predicting THA response. Moreover, it suggests that further analysis of the subtle role of transverse plane hip mechanics could lead to interventions to promote better THA response. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:366-376, 2017.

Gait abnormalities before and after total hip arthroplasty differ in men and women.

This study tested the hypothesis that men and women have different preoperative and postoperative gait impairment relative to sex-matched healthy controls, and that the extent of gait improvement after total hip arthroplasty (THA) is different between men and women. A group of 124 THA subjects was identified from a motion analysis data repository; age and BMI-matched male and female control groups were then identified from the same repository. Dynamic sagittal plane hip range of motion (HROM) and peak 3D external moments at subjects' normal walking speeds were analyzed. Each hypotheses was tested using linear regression models, to adjust for potential confounding effects of walking speed. Preoperatively, the THA vs. control group differences in the HROM and peak adduction moments were larger in women than they were in men (p=0.007). The THA group vs. control group difference in the peak external rotation moment was larger in men (p=0.004). After surgery, HROM increased more in women than in men (p=0.020). However, peak adduction moment decreased in men but increased in women (-0.11±0.93 vs. 0.28±1.3%BWH, p=0.045). Accordingly, postoperatively the THA group vs. control group differences in the peak external rotation moment remained larger in men than in women (p=0.016). There were no other sex-specific differences (p=0.072-0.876). This study suggests that men and women have slightly different patterns of gait recovery after THA and may benefit from sex-specific rehabilitation strategies. These differences also underscore the importance of accounting for sex in biomechanical studies.

Acetabular Osteoarticular Allograft After Ewing Sarcoma Resection: A 15-Year Follow-up: A Case Report.

CASE: A 4-year-old girl with Ewing sarcoma of the periacetabular region had been treated with neoadjuvant chemotherapy followed by resection and osteoarticular allograft reconstruction with an adult hemipelvis. At 15 years postoperatively, she remained disease-free with remarkable functionality. She had minimal groin pain and could walk an unlimited distance. Radiographs demonstrated union at the anastomotic junctions. The allograft, which had been considerably oversized 15 years ago, was now identical in size to the contralateral ilium. CONCLUSION: Osteoarticular allograft remains one of the best reconstructive options following hemipelvectomy in the pediatric population because of its potential durability and its capacity to restore pelvic stability and preserve functionality.

Contralateral hip and knee gait biomechanics are unchanged by total hip replacement for unilateral hip osteoarthritis.

Both the hip and knee contralateral to a total hip replacement (THR) have an increased risk of osteoarthritis (OA) progression, and ultimate joint replacement. It is also known that abnormal gait contributes to OA progression. For these reasons, we conducted a longitudinal analysis of contralateral hip and knee gait during the first year after unilateral THR to determine whether abnormal contralateral gait biomechanics emerge after THR. We analyzed the sagittal plane dynamic range of motion and 3D peak external moments from the asymptomatic hip and knee contralateral to a THR in a group of 26 subjects, evaluated preoperatively, and 3, 12, 24, and 52 weeks after THR, and a group of control subjects. We used t-tests and repeated measures ANOVA to test the hypotheses that contralateral hip and knee gait parameters are normal preoperatively, but change after THR. Preoperatively, the contralateral hip abduction moment and the contralateral knee adduction, flexion, and external rotation moments were significantly higher than normal in the THR group (p ≤ 0.048). Apart from the peak hip extension moment, which decreased three weeks after surgery but returned to its preoperative value thereafter, there were no longitudinal changes during the study period (p ≥ 0.141). Preoperative gait abnormalities persisted postoperatively. Notably, the contralateral knee adduction moment was 32% higher than normal in the THR group. These results indicate a biomechanical basis for the increased contralateral OA risk after unilateral THR, and suggest that some patients may benefit from strategies to reduce loading on the contralateral limb.

Time course and extent of functional recovery during the first postoperative year after minimally invasive total hip arthroplasty with two different surgical approaches--a randomized controlled trial.

UNLABELLED: While others have reported short-term comparisons between various minimally invasive surgical (MIS) approaches to total hip arthroplasty (THA) and their conventional analogues, longer-term data is lacking, as is information indicating whether MIS approaches to THA provide a biomechanically complete recovery. Furthermore, different MIS approaches have not been compared. Our approaches of interest were a one-incision modified Watson-Jones, and a two-incision approach. HYPOTHESES: (1) There are significant differences in gait recovery patterns between the two surgical groups and (2) THA subjects have significant differences in function one year after surgery compared to control subjects. To test these hypotheses, THA candidates (n=26) were randomized to receive one of these MIS approaches and evaluated preoperatively, and postoperatively at 3 weeks, and at 3, 6 and 12 months. Evaluations included three-dimensional gait analysis and 24-hour step-counts. The same data were obtained from 25 control subjects. Recovery time-course was assessed using repeated measures ANOVA. T-tests were used to compare controls with the pooled group of THA subjects. We found no differences between the two THA surgical groups regarding the time-course of recovery (p≥0.591). Although recovery was statistically complete by 3 months postoperatively for all variables, there were significant differences from controls at 12 months. Most notably, the external hip adduction moment, which reflects hip abductor function, was more than one standard deviation below normal (p<0.001). THA subject inactivity could not explain the gait differences, since one year after surgery daily step counts were not significantly different from controls (p=0.346). More work is necessary to determine ways to improve biomechanical outcomes for today's patients with high expectations for function and implant longevity.

Differences in preferred walking speeds in a gait laboratory compared with the real world after total hip replacement.

OBJECTIVE: To evaluate the relation between walking speeds measured in a gait laboratory and those measured in real-world settings (habitual speed) in subjects with total hip replacements (THRs) and control subjects. The secondary objective is to determine whether the relationship between gait laboratory and habitual speeds was affected by recovery time or related to clinical indices. DESIGN: Cohort study. SETTING: Academic medical center. PARTICIPANTS: Experimental subjects (n=26) evaluated 3 weeks and 12 months after THR and control subjects (n=24). INTERVENTIONS: None. MAIN OUTCOME MEASURES: Walking speed measured in the gait laboratory, walking speed measured in the field by using activity monitors, Harris Hip Score (HHS), and the Western Ontario and McMaster Osteoarthritis Index (WOMAC). RESULTS: Laboratory speeds were significantly faster than habitual speeds in all groups (P<.001), but the 2 correlated significantly. The laboratory versus habitual-speed difference was unaffected by recovery time within the THR group (P=.180) but was larger for control subjects (.32+/-.21m/s) than for THR subjects (.19+/-.15m/s 1 year after surgery). Habitual speed significantly correlated with total WOMAC scores and with WOMAC stiffness and function subscores 3 weeks after THR. The HHS weakly correlated with 3-week laboratory speed. No speed and clinical correlations were seen 1 year after THR. CONCLUSIONS: Although subjects may exaggerate walking speeds in laboratory settings, laboratory-based data accurately reflect real-world activity. Setting affected speeds most in the control group. It is important to consider potential discrepancies between speeds walked in a laboratory versus in the real world when interpreting gait studies comparing 2 or more populations. Finally, analysis of these data suggests that clinical indices may more accurately reflect biomechanical function during early recovery after THR than after full recovery.

Relative importance of gait vs. joint positioning on hip contact forces after total hip replacement.

Implant loosening is a common indication for total hip replacement (THR) revision. High contact forces and implant twisting moments are thought to be associated with implant loosening. Relationships between joint positioning and hip forces, or outcomes, have been investigated through in vivo and in vitro modalities. Relationships between hip forces and gait are less understood, despite repeated findings that gait following a THR does not fully return to normal. We tested the hypothesis that gait parameters would be better predictors of implant force (peak contact forces and peak twisting moment during walking) than joint positioning parameters. Subjects underwent gait analysis, hip force modeling, and measurement of clinical radiographs 1 year after successful THR surgery. Gait parameters were consistently more influential in determining hip forces. Alone, gait explained as much as 67% of the variation in force, compared to a maximum of 33% by joint geometry. Combinations of gait and joint positioning parameters together explained up to 86% of the variation in hip force parameters. Results suggest that gait may provide a valuable postoperatively modifiable target to improve hip loads and potentially reduce the risk for implant loosening.

Preoperative gait adaptations persist one year after surgery in clinically well-functioning total hip replacement patients.

The purpose of this study was to evaluate whether preoperative gait adaptations persist one year after THR in the same set of subjects. The hypothesis tested was that hip dynamic range of motion and peak external moments during walking return to normal after THR. Hip kinematics and kinetics were measured for 28 subjects before and one year after THR and compared to those of 25 subjects with radiographically normal hips. All THR subjects improved clinically after surgery with Harris hip scores improving from 33-85 (average 53) to 61-100 (average 95) (sign test p<0.001). Preoperatively dynamic hip range of motion (ROM), and all peak external moments were reduced compared to normal (Mann-Whitney p< or =0.040). Improvement was seen in the ROM and all but the frontal plane, and external rotation peak moments (Friedman p< or =0.023). The preoperative and postoperative values of the ROM, and peak flexion, abduction and external rotation moments were all significantly correlated (Spearman p<0.020) indicating a possible learned effect from before THR surgery. Postoperative THR subjects continued to have a significantly lower than normal ROM, and peak adduction and peak internal rotation moments (Mann-Whitney p< or =0.003). Despite good to excellent clinical functional outcome, gait in THR patients does not return to normal by one year after surgery. Aggressive muscle strengthening is currently not emphasized after THR surgery. Some THR patients may benefit from more intensive rehabilitation before and after surgery.