Early outcome of humeral head replacement with glenoid reaming arthroplasty (Ream and Run) for treatment of advanced glenohumeral osteoarthritis.

INTRODUCTION: Long-term outcomes of anatomic total shoulder arthroplasty (aTSA) can be compromised by glenoid loosening and failure. The purpose of this study was to evaluate the short- and midterm outcomes of humeral head replacement with glenoid reaming arthroplasty (Ream and Run) for the treatment of advanced glenohumeral osteoarthritis, and to identify associations between preoperative factors and outcomes. METHODS: Forty-nine shoulders (mean age 60 ± 7 years) with minimum 2-year follow-up (mean 4.6 ± 1.7) were evaluated. Forty-three (87.8%) were male. Thirteen (26.5%) had previous nonarthroplasty shoulder surgery. There were 19 (38.8%) Walch type A and 30 (61.2%) type B glenoids. Pre- and postoperative shoulder motion, patient-reported outcomes (PROMs), and health-related quality of life (HRQoL) were assessed. Pre- and postoperative plain radiographs were evaluated. Mixed effects models were used to investigate factors associated with outcomes. RESULTS: Active forward elevation and active external rotation improved from 111.7° ± 23.8° to 139.2° ± 21.1° and 13.3° ± 20.7° to 38.7° ± 14.7°, respectively (P < .001). The mean American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH), Simple Shoulder Test (SST), and visual analog scale (VAS) shoulder pain scores at the most recent follow-up were 86.6 ± 19.9, 10.1 ± 14.1, 10.5 ± 2.2, and 1.5 ± 2.3, respectively. The mean changes of PROMs were significant and exceeded the minimal clinically important difference for aTSA. The percentage maximal possible improvement for ASES, DASH, and SST were greater than 75%. Male sex (P < .008) and not having prior shoulder surgery (P < .04) were significantly associated with better absolute and greater change in PROMs. Age, preoperative shoulder motion, and Walch glenoid classification were not associated with PROMs. Five (10.2%, 95% confidence interval [CI] 1.8%-18.6%) patients underwent revision for pain. Three additional patients were dissatisfied at final follow-up without undergoing revision, resulting in 16.7% (95% CI 6.1%-27.2%) of patients being dissatisfied with their outcome after their initial RnR. Mean Short Form-6 Dimensions scores improved from 0.66 ± 0.12 to 0.77 ± 0.13 and mean EuroQol-5 Dimensions scores improved from 0.68 ± 0.20 to 0.85 ± 0.17 (P < .001). Improvement in HRQoL was significantly associated with nondominant arm treatment, increased age, and greater preoperative SST score. Annual medialization of the humeral head center of rotation was 0.56 ± 1.6 mm/yr. No radiographic measure was associated with long-term PROMs. CONCLUSION: Ream and Run can provide significant and clinically important improvement in PROMs and HRQoL for a high percentage of patients at short- and midterm follow-up. This procedure is an appropriate alternative to aTSA in select patients.

Changes in Proximal Femoral Shape During Fetal Development.

BACKGROUND: Walker and Goldsmith's classic article on fetal hip joint development reported that neck/shaft angle did not change from 12 weeks of gestational age through term while version increased from 0 to 40 degrees. This suggests no change in coronal alignment during development, a conclusion we dispute. By re-examining their data, we found that the true neck/shaft angle (tNSA) decreased by 7.5 degrees as version increased by 40 degrees from 12 weeks of gestational age to term. METHODS: Four investigators measured both femoral version and neck-shaft angle from photographs published by the authors of femurs at multiple stages of maturation from 12 weeks of gestational age to term. The tNSAs and inclination angles were calculated for each femur illustrated using previously validated formula. Changes in the morphology of the femur over time were analyzed using a Student t test. Interobserver and intraobserver reliability were also determined by the Pearson R coefficient. RESULTS: As reported by Walker and Goldsmith, apparent neck/shaft angle (aNSA) did not significantly change during maturation, whereas version increased by 40 degrees. However, tNSA decreased by 7.5 degrees during maturation, while the inclination increased by 32 degrees over the same period. This paper demonstrates angular changes in both the coronal and transverse planes with a 4:1 ratio of angular change in the transverse and coronal planes respectively. Interobserver Pearson coefficient R=0.98 and an intraobserver Pearson coefficient R=0.99. CONCLUSIONS: Although Walker and Goldsmith reported angular changes only in the transverse plane, we conclude that they identified angular changes in both the coronal and transverse planes. Here we show it is mathematically necessary for tNSA to decrease, if aNSA remains constant as version increases. CLINICAL RELEVANCE: A reader who is not well versed in the difference between aNSA and tNSA or version and inclination cannot appreciate what Walker and Goldsmith presented. Surgeons operating on the proximal femur also benefit from understanding these distinctions.

Ibuprofen impairs capsulolabral healing in a rat model of anterior glenohumeral instability.

BACKGROUND: Failure of glenoid labrum and capsular healing after glenohumeral dislocation can lead to persistent shoulder instability. The purpose of this study was to determine the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the healing glenoid labrum and capsule after glenohumeral dislocation in a rat model. METHODS: Sixty-six rats had surgically induced anterior-inferior labral tears and anterior glenohumeral dislocation. Postoperatively, the animals were assigned to either normal (n = 32) or ibuprofen drinking water (n = 31). Animals were euthanized at 2 and 4 weeks postoperatively for biomechanical testing and histologic analysis. RESULTS: The maximum load increased from 2 to 4 weeks after injury in the NSAID groups but not in the control groups. At 2 weeks, the maximum load was lower in the NSAID group compared with the control group. In a matched comparison between injured and uninjured limbs, the maximum load was significantly decreased in the injured limb of the 2-week NSAID group. At 4 weeks, the NSAID group had decreased stiffness compared with the 4-week control group. CONCLUSIONS: In a new rat model of glenohumeral instability, the postinjury administration of ibuprofen resulted in decreased capsulolabral healing. A matched pair analysis of injured to uninjured limbs supported the findings of impaired healing in the NSAID-treated animals. These findings demonstrate that the use of NSAIDs after glenohumeral dislocation may impair capsulolabral healing and should be limited or avoided to optimize glenohumeral stability.

A Modified Ogata-Goldsand Technique for Simplified Intraoperative Measurement of Femoral Version.

BACKGROUND: Femoral anteversion can be difficult to determine intraoperatively, particularly in cases with complicated deformity. Although biplanar methodology exists for measuring femoral anteversion, the measurements are generally based on the proximal femur, without consideration for the femoral bow. METHODS: We directly measured femoral version in 70 mature cadaveric femora. Using the standard Ogata-Goldsand approach, femoral version was geometrically calculated after measuring apparent neck-shaft angle and the ß-angle, which is the angle between the femoral neck and proximal femoral shaft on a direct lateral view. We then used a modified ß-angle, measured between the femoral neck and a line representing the entire femur. RESULTS: Mean anatomic femoral anteversion was 20±11 degrees. Mean calculated femoral version using the standard Ogata-Goldsand technique was 32±13 degrees, whereas mean calculated femoral version using the modified Ogata-Goldsand technique was 22±12 degrees. Repeated measures ANOVA analysis found an overall statistically significant difference between the 3 groups (P<0.0001). Pairwise comparisons revealed a significant difference between directly measured version and the standard Ogata-Goldsand technique (P<0.0001) but not between directly measured version and the modified Ogata-Goldsand technique (P=0.76). CONCLUSIONS: Standard biplanar imaging techniques do not account for the femoral bow and can significantly overestimate femoral anteversion. If a line is drawn from the posterior femoral condyles to the posterior aspect of the greater trochanter, femoral anteversion is better approximated. Intraoperatively, we obtain this line by positioning a marker over the skin under fluoroscopy. Clinically, if one aims for a modified ß-angle of 5 degrees, a postosteotomy anteroposterior radiograph is no longer necessary, given the knowledge that with apparent neck-shaft angles ranging from 115 to 155 degrees, version will lie within a generally accepted range between 2 and 11 degrees. CLINICAL RELEVANCE: In complex operative cases where imaging is desired to measure intraoperative femoral version, we recommend a modified and simplified lateral view measurement technique, which improves accuracy by accounting for the femoral bow.

Treatment of a Complex Interprosthetic Humerus Fracture.

Interprosthetic humeral shaft fractures involving shoulder and elbow arthroplasty can be difficult to manage surgically, both due to fracture and patient characteristics. Adequate fixation can be difficult, given the intramedullary nature of the adjacent implants. Careful attention must be paid to regional anatomy, and care must be taken to not damage the radial or ulnar nerve during dissection and mobilization of the fracture, especially if scar tissue exists from multiple previous surgeries. Finally, fixation strategies must be used to gain stability in areas where there is a cement mantle or well-fixed intramedullary stem to impart the stability required for adequate healing and postoperative mobilization. Biologic augmentation is often used as well, given the relatively poor biologic environment for bone healing. We review our technique for operative fixation of a patient with a humeral shaft fracture between a cemented shoulder hemiarthroplasty and total elbow arthroplasty.

Popliteal Artery Entrapment Syndrome: Bilateral Lower Extremity Involvement.

Popliteal artery entrapment syndrome is a condition in which compression of the popliteal neurovascular structures results in symptoms of lower extremity claudication by way of a constricting anatomic structure or a hypertrophied surrounding musculature. This diagnosis is often missed or misdiagnosed because popliteal artery entrapment syndrome has a presentation similar to that of exertional compartment syndrome. Popliteal artery entrapment syndrome may result in persistent disability or unnecessary morbidity or prevent athletes' return to sport. A female collegiate athlete presented with bilateral popliteal artery entrapment syndrome. She had successful surgical treatment and returned to a high level of sport. This article describes popliteal artery entrapment syndrome, emphasizes the importance of a thorough history and physical examination to elucidate the diagnosis, and provides information that may lead to the identification of individuals who will benefit from surgical intervention. [Orthopedics. 2018; 41(2):e295-e298.].

The cost of running uphill: linking organismal and muscle energy use in guinea fowl (Numida meleagris).

Uphill running requires more energy than level running at the same speed, largely due to the additional mechanical work of elevating the body weight. We explored the distribution of energy use among the leg muscles of guinea fowl running on the level and uphill using both organismal energy expenditure (oxygen consumption) and muscle blood flow measurements. We tested each bird under four conditions: (1) rest, (2) a moderate-speed level run at 1.5 m s(-1), (3) an incline run at 1.5 m s(-1) with a 15% gradient and (4) a fast level run at a speed eliciting the same metabolic rate as did running at a 15% gradient at 1.5 m s(-1) (2.28-2.39 m s(-1)). The organismal energy expenditure increased by 30% between the moderate-speed level run and both the fast level run and the incline run, and was matched by a proportional increase in total blood flow to the leg muscles. We found that blood flow increased significantly to nearly all the leg muscles between the moderate-speed level run and the incline run. However, the increase in flow was distributed unevenly across the leg muscles, with just three muscles being responsible for over 50% of the total increase in blood flow during uphill running. Three muscles showed significant increases in blood flow with increased incline but not with an increase in speed. Increasing the volume of active muscle may explain why in a previous study a higher maximal rate of oxygen consumption was measured during uphill running. The majority of the increase in energy expenditure between level and incline running was used in stance-phase muscles. Proximal stance-phase extensor muscles with parallel fibers and short tendons, which have been considered particularly well suited for doing positive work on the center of mass, increased their mass-specific energy use during uphill running significantly more than pinnate stance-phase muscles. This finding provides some evidence for a division of labor among muscles used for mechanical work production based on their muscle-tendon architecture. Nevertheless, 33% of the total increase in energy use (40% of the increase in stance-phase energy use) during uphill running was provided by pinnate stance-phase muscles. Swing-phase muscles also increase their energy expenditure during uphill running, although to a lesser extent than that required by running faster on the level. These results suggest that neither muscle-tendon nor musculoskeletal architecture appear to greatly restrict the ability of muscles to do work during locomotor tasks such as uphill running, and that the added energy cost of running uphill is not solely due to lifting the body center of mass.

The energetic costs of trunk and distal-limb loading during walking and running in guinea fowl Numida meleagris: I. Organismal metabolism and biomechanics.

We examined the energetic cost of loading the trunk or distal portion of the leg in walking and running guinea fowl (Numida meleagris). These different loading regimes were designed to separately influence the energy use by muscles used during the stance and swing phases of the stride. Metabolic rate, estimated from oxygen consumption, was measured while birds locomoted on a motorized treadmill at speeds from 0.5 to 2.0 m s-1, either unloaded, or with a mass equivalent to 23% of their body mass carried on their backs, or with masses equal to approximately 2.5% of their body mass attached to each tarsometatarsal segment. In separate experiments, we also measured the duration of stance and swing in unloaded, trunk-loaded, or limb-loaded birds. In the unloaded and limb-loaded birds, we also calculated the mechanical energy of the tarsometatarsal segment throughout the stride. Trunk and limb loads caused similar increases in metabolic rate. During trunk loading, the net metabolic rate (gross metabolic rate-resting metabolic rate) increased by 17% above the unloaded value across all speeds. This percentage increase is less than has been found in most studies of humans and other mammals. The economical load carriage of guinea fowl is consistent with predictions based on the relative cost of the stance and swing phases of the stride in this species. However, the available comparative data and considerations of the factors that determine the cost of carrying extra mass lead us to the conclusion that the cost of load carrying is unlikely to be a reliable indicator of the distribution of energy use in stance and swing. Both loading regimes caused small changes in the swing and/or stance durations, but these changes were less than 10%. Loading the tarsometatarsal segment increased its segmental energy by 4.1 times and the segmental mechanical power averaged over the stride by 3.8 times. The increases in metabolism associated with limb loading appear to be linked to the increases in mechanical power. The delta efficiency (change in mechanical power divided by the change in metabolic power) of producing this power increased from 11% in walking to approximately 25% in running. Although tarsometatarsal loading was designed to increase the mechanical energy during swing phase, 40% of the increase in segmental energy occurred during late stance. Thus, the increased energy demand of distal limb loading in guinea fowl is predicted to cause increases in energy use by both stance- and swing-phase muscles.

Performance of guinea fowl Numida meleagris during jumping requires storage and release of elastic energy.

The ability of birds to perform effective jumps may play an important role in predator avoidance and flight initiation. Jumping can provide the vertical acceleration necessary for a rapid takeoff, which may be particularly important for ground-dwelling birds such as phasianids. We hypothesized that by making use of elastic energy storage and release, the leg muscles could provide the large power outputs needed for achieving high velocities after takeoff. We investigated the performance of the leg muscles of the guinea fowl Numida meleagris during jumping using kinematic and force-plate analyses. Comparison of the methods indicated that in this species the wings did not supply energy to power takeoff and thus all the work and power came from the leg muscles. Guinea fowl produced a peak vertical force of 5.3 times body weight. Despite having lower muscle-mass-specific power output in comparison to more specialized jumpers, guinea fowl demonstrated surprisingly good performance by producing muscle-mass-specific work outputs of 45 J kg(-1), a value approximately two thirds of the maximal expected value for skeletal muscle. The muscle-mass-specific peak power output during jumping was nearly 800 W kg(-1), which is more than twice the peak isotonic power estimated for guinea fowl leg muscles. To account for high power outputs, we concluded that energy has to be stored early in the jumps and released later during peak power production, presumably using mechanisms similar to those found in more specialized jumpers.

Blood flow in guinea fowl Numida meleagris as an indicator of energy expenditure by individual muscles during walking and running.

Running and walking are mechanically complex activities. Leg muscles must exert forces to support weight and provide stability, do work to accelerate the limbs and body centre of mass, and absorb work to act as brakes. Current understanding of energy use during legged locomotion has been limited by the lack of measurements of energy use by individual muscles. Our study is based on the correlation between blood flow and aerobic energy expenditure in active skeletal muscle during locomotion. This correlation is strongly supported by the available evidence concerning control of blood flow to active muscle, and the relationship between blood flow and the rate of muscle oxygen consumption. We used injectable microspheres to measure the blood flow to the hind-limb muscles, and other body tissues, in guinea fowl (Numida meleagris) at rest, and across a range of walking and running speeds. Combined with data concerning the various mechanical functions of the leg muscles, this approach has enabled the first direct estimates of the energetic costs of some of these functions. Cardiac output increased from 350 ml min(-1) at rest, to 1700 ml min(-1) at a running speed ( approximately 2.6 m s(-1)) eliciting a of 90% of . The increase in cardiac output was achieved via approximately equal factorial increases in heart rate and stroke volume. Approximately 90% of the increased cardiac output was directed to the active muscles of the hind limbs, without redistribution of blood flow from the viscera. Values of mass-specific blood flow to the ventricles, approximately 15 ml min(-1) g(-1), and one of the hind-limb muscles, approximately 9 ml min(-1) g(-1), were the highest yet recorded for blood flow to active muscle. The patterns of increasing blood flow with increasing speed varied greatly among different muscles. The increases in flow correlated with the likely fibre type distribution of the muscles. Muscles expected to have many high-oxidative fibres preferentially increased flow at low exercise intensities. We estimated substantial energetic costs associated with swinging the limbs, co-contraction to stabilize the knee and work production by the hind-limb muscles. Our data provide a basis for evaluating hypotheses relating the mechanics and energetics of legged locomotion.

Partitioning the energetics of walking and running: swinging the limbs is expensive.

Explaining the energetics of walking and running has been difficult because the distribution of energy use among individual muscles has not been known. We estimated energy use by measuring blood flow to the hindlimb muscles in guinea fowl. Blood flow to skeletal muscles is controlled locally and varies directly with metabolic rate. We estimate that the swing-phase muscles consume 26% of the energy used by the limbs and the stance-phase muscles consume the remaining 74%, independent of speed. Thus, contrary to some previous suggestions, swinging the limbs requires an appreciable fraction of the energy used during terrestrial legged locomotion. Models integrating the energetics and mechanics of running will benefit from more detailed information on the distribution of energy use by the muscles.