Search Results
Abstract
Background: Ideal suture technique and type in tendon repair are remain unclear. This biomechanical study aimed to assess the biomechanical characteristics of three techniques, modified Kessler (mKE), modified Krackow (mKR), and modified tension Bunnell (mtBU), in sheep Achilles’ tendon tear repair using three suture types, polypropylene, polyester, and ultra-high molecular weight polyethylene (UHMWPE) sutures, which are also compared.
Methods: Sixty-three Achilles’ tendons harvested from sheep were transversely hacked as a replacement for rupture in a standardized measure and repaired using mKE, mKR, and mtBU techniques with No. 2 polypropylene, polyester, and UHMWPE sutures. Biomechanical parameters, such as Young’s modulus, ultimate strength, and strength to the 5-mm gap were recorded for statistical analysis.
Results: The mtBU technique with UHMWPE use resulted in increased ultimate strength, strenght to 5-mm gap, Young’s modulus, and quantity of specimens with low clinical failure modes compared to other techniques with other suture materials. Furthermore, mtBU has the lowest thickness at the repair side of the tendons. This approach showed tendon failure during maximal traction testing, whereas the mKE and mKR had polyethylene and polyester suture failures.
Conclusions: The UHMWPE suture was significantly superior to the other sutures in each suture techniques in terms of strength and durability. The mtBU technique using UHMWPE suture showed better biomechanical results, implying that this repair might be more appropriate to obtain early mobilization after tendon ruptures.
Foot Biomechanics in Patients with Diabetes Mellitus
Doubts Regarding the Relationship Between Neuropathy, Foot Motion, and Deformities
Background:
We sought to identify the biomechanical characteristics of the feet of patients with diabetes mellitus and the interrelationship with diabetic neuropathy by determining the range of joint mobility and the presence and locations of calluses and foot deformities.
Methods:
This observational comparative study involved 281 patients with diabetes mellitus who underwent neurologic and vascular examinations. Joint mobility studies were performed, and deformities and hyperkeratosis locations were assessed.
Results:
No substantial differences were found between patients with and without neuropathy in joint mobility range. Neuropathy was seen as a risk factor only in the passive range of motion of the first metatarsophalangeal joint (mean ± SD: 57.2° ± 19.5° versus 50.3° ± 22.5°, P = .008). Mean ± SD ankle joint mobility values were similar in both groups (83.0° ± 5.2° versus 82.8° ± 9.3°, P = .826). Patients without neuropathy had a higher rate of foot deformities such as hallux abductus valgus and hammer toes. There was also a higher presence of calluses in patients without neuropathy (82.8% versus 72.6%; P = .039).
Conclusions:
Diabetic neuropathy was not related to limited joint mobility and the presence of calluses. Patients with neuropathy did not show a higher risk of any of the deformities examined. These findings suggest that the etiology of biomechanical alterations in diabetic people is complex and may involve several anatomically and pathologically predisposing factors. (J Am Podiatr Med Assoc 101(3): 208–214, 2011)
Biomechanical Consequences of Total Plantar Fasciotomy
A Review of the Literature
Background: Plantar fascia release for chronic plantar fasciitis has provided excellent pain relief and rapid return to activities with few reported complications. Cadaveric studies have led to the identification of some potential postoperative problems, most commonly weakness of the medial longitudinal arch and pain in the lateral midfoot.
Methods: An electronic search was conducted of the MEDLINE, ScienceDirect, SportDiscus, EMBASE, CINAHL, Cochrane, and AMED databases. The keywords used to search these databases were plantar fasciotomy and medial longitudinal arch. Articles published between 1976 and 2008 were identified.
Results: Collectively, results of cadaveric studies suggested that plantar fasciotomy leads to loss of integrity of the medial longitudinal arch and that total plantar fasciotomy is more detrimental to foot structure than is partial fasciotomy. In vivo studies, although limited in number, concluded that although clinical outcomes were satisfactory, medial longitudinal arch height decreased and the center of pressure of the weightbearing foot was excessively medially deviated postoperatively.
Conclusions: Plantar fasciotomy, in particular total plantar fasciotomy, may lead to loss of stability of the medial longitudinal arch and abnormalities in gait, in particular an excessively pronated foot. Further in vivo studies on the long-term biomechanical effects of plantar fasciotomy are required. (J Am Podiatr Med Assoc 99(5): 422–430, 2009)
Turner syndrome is a genetic disorder that can present clinically with multiple concurrent comorbidities. This case report describes a 12-year-old girl with Turner syndrome who was referred for podiatric medical assessment and explores the application of optoelectronic stereophotogrammetry in the biomechanical assessment of the foot and lower limb. A four-segment kinematic foot model using 14-mm reflective markers was applied to the foot and lower limb of the patient to track motion at the tibia, rearfoot, forefoot, and hallux. Kinematic results presented in this case study illustrate evidence of excessive foot pronation throughout the stance phase of gait. Whether excessive pronation is a general characteristic of foot function in Turner syndrome remains to be confirmed, but the findings presented suggest that a comprehensive evaluation of foot biomechanics in patients with Turner syndrome may be warranted. (J Am Podiatr Med Assoc 102(3): 259–263, 2012)
The reliability of biomechanical measurements of the lower extremities, as they are commonly used in podiatric practice, was quantified by means of intraclass correlation coefficients (ICCs). This was done not only to evaluate interrater and intrarater reliability but also to provide an estimate for the accuracy of the measurements. The measurement protocol involved 30 asymptomatic subjects and five raters of varying experience. Each subject was measured twice by the same rater, with the retest immediately following the test. The study demonstrated that the interrater ICCs were quite low (≤0.51), except for the measurements of relaxed calcaneal stance position and forefoot varus (both 0.61 and 0.62 for left and right, respectively). However, the intrarater ICCs were relatively high (>0.8) for most raters and measurement variables. Measurement accuracy was moderate between raters. (J Am Podiatr Med Assoc 92(6): 317-326, 2002)
Background: Medial tibial stress syndrome is a common overuse injury in weightbearing, physically active individuals and in athletes. Most research associated with this condition is primarily based on static foot and lower-extremity measurements.
Methods: A cross-sectional design was used to assess a set of static and dynamic measurements to determine which anatomical factors (limb length, ankle dorsiflexion, first metatarsophalangeal joint extension, and arch height) and biomechanical factors (center-of-pressure excursion index, malleolar valgus index, and gait velocity) are associated with medial tibial stress syndrome.
Results: One-way analysis of variance models revealed that participants with medial tibial stress syndrome had significantly greater visual analog pain levels and slower gait velocity than noninjured controls (P = .05). No other significant differences were found between the two groups.
Conclusions: Further investigation of these and other factors can help health professionals develop better strategies for the prevention and clinical intervention of medial tibial stress syndrome. (J Am Podiatr Med Assoc 100(2): 121–132, 2010)
The biomechanical effects of talectomy on the foot were investigated in seven fresh below-the-knee amputation specimens using pressure-sensitive films placed on the facets of the calcaneus, footprints, and loading-pattern diagrams in the intact foot and after talectomy with anterior and posterior displacement of the foot. Both talectomy techniques distorted the loads carried by the facets of the calcaneus. In the intact foot, 65.6% of the loads were carried by the posterior facet of the calcaneus and 34.4% by the anterior and middle facets. After talectomy with anterior displacement of the foot, although the loads carried by the anterior and middle facets decreased significantly (P = .018), the increase in the loads carried by the posterior facet was not significant compared with the intact foot (P = .176). Similarly, the loads carried by the posterior facet decreased significantly after talectomy with posterior displacement of the foot (P = .028), but the increases in the loads carried by the anterior and middle facets were not significant (P = .735). Comparing the two types of talectomy, the loads carried by each facet changed significantly (P = .018). Talectomy with posterior displacement of the foot also changed the loading patterns and resulted in significant pronation of the foot. These results suggest that talectomy should be performed only as a salvage procedure and that talectomy with anterior displacement of the foot may be preferred when talectomy is indicated. (J Am Podiatr Med Assoc 96(6): 495–498, 2006)
Background:
We sought to show the biomechanical and morphometric properties of flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendon grafts harvested by specific surgical approaches and to assess the contribution of FHL slips to the long flexor tendons of the toes.
Methods:
Thirteen fresh-frozen amputated feet (average age, 79 years) were dissected. The connections between the FHL and FDL tendons and the contribution of FHL slips to the long flexor tendons were classified. The biomechanical properties of the tendons and slips were measured using a tensile device.
Results:
The connections between the FHL and FDL tendons were reviewed in two groups. Group 1 had FHL slips (11 cases) and group 2 had cross-slips (two cases). The FHL slips joined the second and third toe long flexor tendon structures. Tendon length decreased significantly from the second to the fifth toe (P < .001). Apart from the second toe tendon being thicker than that of the fourth toe (P = .02) and Young's modulus being relatively smaller in the third versus the fourth toe tendon (P = .01), biomechanical and morphometric properties of second to fourth tendons were similar. Mechanical properties of those tendons were significantly different from fifth toe tendons and FHL slips. Morphometric and biomechanical properties of FHL slips were similar to those of the fifth toe tendon.
Conclusions:
Herein, FHL slips were shown to have biomechanical properties that might contribute to flexor functions of the toes. During the harvesting of tendon grafts from the FHL by minimally invasive incision techniques from the distal plane of the master knot of Henry, cutting slips between FHL and FDL tendons could be considered a cause of postoperative function loss in toes.
Professional dancers have a 90% risk of injury during their career. The lower extremity is involved in approximately 75% of the injuries sustained by dancers. Proper biomechanical evaluation, risk assessment, and prevention-oriented treatment are necessary to minimize future problems and promote a full and lasting recovery when an injury is sustained. This article outlines the in-office evaluation process and discusses backstage care. (J Am Podiatr Med Assoc 97(1): 75–80, 2007)
