Early results of reconstruction of the dorsal scapholunate ligament

Abstract

We present the clinical results of a study of chronic dynamic scapholunate (SL) dissociation treated by reconstruction of the dorsal SL ligament. A total of 35 patients who presented with chronic dynamic SL instability had the scapholunate ligament reconstructed with a tendon graft. Twenty-nine patients were available for follow-up evaluation after a minimal interval of 17 months (range 17–72). Patients' satisfaction was good in 26/29 patients. Postoperative range of movement was reduced in extension and improved for flexion and ulnar deviation. Mean wrist movements were 75% of those on the opposite side. Most patients had good pain relief and recovered their grip strength, and returned to their regular employment. Follow-up stress radiographs showed a reduction in the SL angle and gap. Reconstruction of the dorsal SL ligament provides sufficient restoration of stability, pain relief, and functional improvement of the wrist for patients with dynamic SL instability. Although the short-term results are encouraging, we think that this method should be verified by longer follow-up.     

Rupture of the extensor pollicis longus tendon: a study of aetiological factors

Although rupture of the extensor pollicis longus (EPL) tendon is a wellknown complication of distal radial fractures, a number of patients rupture the EPL because of other conditions. We have retrospectively studied the aetiology of 27 ruptures of the EPL in 26 consecutive patients. Of 19 patients with injured wrists 12 had distal radial fractures, five had blunt trauma, and two had stab wounds that resulted in rupture. In the radial fractures operated on, the EPL rupture was caused by chafing against a dorsal plate (n?=?2) or wear against the pins of an external fixator (n?=?2). Six patients were taking steroids for systemic diseases and in two cases a local steroid injection was given just before the rupture. We conclude that previous injury is the most common cause of rupture of the EPL, but that rheumatoid arthritis or local or systemic steroids, or both, are also important aetiological factors. Seven patients had an iatrogenic cause for their rupture.     

Model for assessment of mobility of toes and healing of tendons in rabbits

Abstract

Repair of a transected flexor tendon will, despite careful technique and early rehabilitation, usually result in a restricted range of movement. This is mainly because adhesions form between the tendon and the surrounding structures. Our aim was to establish an experimental model in rabbits for future studies on new techniques to reduce the formation of adhesions after zone II repair of flexor tendons. In rabbits' hind paws the metatarsal bones II, IV, and V were removed and the flexor tendon was freed to the metatarsophalangeal (MTP) joint. The digits were secured in a specifically-designed biomechanical testing device comprising a servo-hydraulic actuator that was designed to apply controlled force or displacement. The tests were videotaped with a digital force-monitor behind the tested digit. Paper printouts from the recordings were obtained for 0, 0.5, 1, 2, 3, 4, and 5 Newton (N) and metatarsophalangeal, proximal interphalangeal, and distal interphalangeal, angles and distances between metatarsophalangeal joints and claws were measured. The tensile strength of the tendon was evaluated by a load-to-failure test. The continuous data obtained from the experiments were used to calculate functional stiffness at the selected forces. The model allows for unique continuous recordings of mobility of toes, thereby indirectly quantifying the presence of adhesions and the assessment of tensile strength. The data are reproducible, and there is little variation between the digits tested. The model is primarily intended to compare data among treated and non-treated digits of methods to limit the formation of adhesions after tendons have been repaired.     

Suppression of the production of extracellular matrix and α-smooth muscle actin induced by transforming growth factor-β1 in fibroblasts of the flexor tendon sheath by hepatocyte growth factor

We examined the effectiveness of hepatocyte growth factor (HGF) in blocking production of transforming growth factor (TGF)-β1-induced collagen I, fibronectin, and α-smooth muscle actin (α-SMA) in the flexor tendon sheath of rabbits in vitro. Fibroblasts were obtained from the sheaths. Cell culture was supplemented with TGF-β1 5 ng/ml and increasing doses of HGF (10-40 ng/ml). The production of collagen I and fibronectin in supernatants culture were examined using an enzyme-linked immunosorbent assay (ELISA). α-SMA expression was assessed by western blot. TGF-β1 stimulated production of collagen I, fibronectin, and α-SMA greatly, while HGF significantly (p<0.05) reduced production of all components induced by TGF-β1 in a dose-dependent manner. This suggests that HGF effectively antagonises the action of TGF-β1 in cultured fibroblasts from flexor tendon sheaths. The results provide a cellular and molecular basis for HGF acting as a therapeutic agent for adhesions in flexor tendons.     

Validity and reliability of measurements of aponeurosis dimensions from magnetic resonance images

Muscle performance is closely related to the structure and function of tendons and aponeuroses, the sheet‐like, intramuscular parts of tendons. The architecture of aponeuroses has been difficult to study with magnetic resonance imaging (MRI) because these thin, collagen‐rich connective tissues have very short transverse relaxation (T2) times and therefore provide a weak signal with conventional MRI sequences. Here, we validated measurements of aponeurosis dimensions from two MRI sequences commonly used in muscle‐tendon research (mDixon and T1‐weighted images), and an ultrashort echo time (UTE) sequence designed for imaging tissues with short T2 times. MRI‐based measurements of aponeurosis width, length, and area of 20 sheep leg muscles were compared to direct measurements made with three‐dimensional (3D) quantitative microdissection. The errors in measurement of aponeurosis width relative to the mean width were 1.8% for UTE, 3.7% for T1, and 18.8% for mDixon. For aponeurosis length, the errors were 7.6% for UTE, 1.9% for T1, and 21.0% for mDixon. Measurements from T1 and UTE scans were unbiased, but mDixon scans systematically underestimated widths, lengths, and areas of the aponeuroses. Using the same methods, we then found high inter‐rater reliability (intraclass correlation coefficients >0.92 for all measures) of measurements of the dimensions of the central aponeurosis of the human tibialis anterior muscle from T1‐weighted scans. We conclude that valid and reliable measurements of aponeurosis dimensions can be obtained from UTE and from T1‐weighted scans. When the goal is to study the macroscopic architecture of aponeuroses, UTE does not hold an advantage over T1‐weighted imaging.     

锚钉技术治疗糖尿病与非糖尿病患者腱性锤状指畸形的疗效分析

目的探讨应用锚钉技术治疗糖尿病与非糖尿病患者腱性锤状指畸形的疗效,评估锚钉技术在治疗糖尿病患者腱性锤状指畸形的临床可行性。 方法前瞻性收集石家庄市第二医院和唐山市第二医院的腱性锤状指畸形糖尿病（试验组）与非糖尿病（对照组）患者各30例,试验组男性15例,女性12例,平均年龄（44.54±4.55）岁,对照组男性13例,女性13例,平均年龄（43.63±4.37）岁,均应用锚钉技术治疗。术后比较两组患者伤口愈合时间;2、3,4个月的患指屈伸运动功能;肌腱愈合情况;并发症发生情况。 结果试验组30例,其中3例失去随访;对照组30例,其中4例失去随访。伤口愈合时间：试验组平均（14.0±1.0）d;对照组平均（13.0±1.1）d,两组比较差异无统计学意义（t=0.087,P>0.05）。末次随访时MP、PIP,DIP屈伸活动度分别为试验组：（89.7±2.4）°、（84.2±5.4）°,（76.3±5.2）°;对照组：（89.0±3.2）°、（84.0±5.3）°,（75.3±5.2）°,两组比较差异分别无统计学意义[（t=1.325,P>0.05）、（t=1.079,P>0.05）,（t=1.553,P>0.05）]。手运动功能TAM分级：试验组优23例,良3例,可1例;对照组优22例,良2例,可2例,两组比较差异无统计学意义（χ²=0.343,P>0.05）。肌腱彩超提示,两组患者均腱骨愈合良好。两组患者术后均无明显并发症发生,可从事正常工作及生活。 结论锚钉技术可有效防止伸肌腱粘连,使患指获得良好的屈伸运动功能,术后并发症少,同样可以用于糖尿病患者腱性锤状指畸形的治疗。     

Relative motion between the flexor digitorum superficialis tendon and paratenon in zone V increases with wrist flexion angle

Carpal tunnel syndrome is characterized by non‐inflammatory fibrosis of the subsynovial connective tissue (SSCT), a paratenon‐like structure inside the carpal tunnel. This pathology suggests repetitive and/or excessive shear forces are involved in injury development. We assessed relative motion between the flexor digitorum superficialis (FDS) tendon and adjacent paratenon in Zone V using colour Doppler imaging as 16 healthy participants completed three long finger movements (metacarpophalangeal joint flexion, proximal and distal interphalangeal joint flexion, full finger flexion) in three wrist postures (30° extension, 0°, 30° flexion). While the type of finger movement did not affect tendon‐paratenon relative motion, we found a significant main effect of wrist posture (p < 0.001). Relative displacement between the FDS tendon and paratenon (as a percentage of tendon displacement) increased from 27.2% (95%CI = 24.8–29.5%) in 30° wrist extension to 39.9% (95%CI = 37.3–42.4%) in 30° wrist flexion. Optical motion capture confirmed that wrist posture did not affect metacarpophalangeal joint range of motion (p = 0.265) or proximal interphalangeal joint range of motion (p = 0.582). These results indicate that relative motion increased due to paratenon strain when the wrist was flexed. While our findings agree with previous cadaveric research in wrist flexion, we found that relative displacement decreased in 30° wrist extension (compared to 0°). These results differ from cadaveric research, possibly due to challenges maintaining anatomic fidelity of the viscoelastic paratenon tissue in vitro. Overall, our study suggests a greater susceptibility to shear injury during repetitive finger movements, particularly when the wrist is flexed. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1248–1255, 2016.     

Use of an IL1‐receptor antagonist to prevent the progression of tendinopathy in a rat model

This study evaluated if inhibiting IL1‐β activity with an IL1‐receptor antagonist (IL1‐RA) will prevent pathologic changes commonly seen in tendinopathy. Thirty‐six Sprague–Dawley retired‐breeder rats were divided into three groups having weekly bilateral patellar tendon injections: CON (0.1 ml Saline), CAR (0.1 ml 2% carrageenan), IL1‐RA (0.1 ml 2% CAR plus 0.94 mg of the IL1‐RA, 2.5 mg/kg). Carrageenan was used to establish tendinopathy in two groups due to its ability to develop tendinopathy in prior studies. Animals were euthanized 3 weeks after initial injection. The CAR group demonstrated significantly (p < 0.05) shorter tendon lengths (8.61 ± 0.38 mm) relative to CON (8.94 ± 0.38 mm) that was prevented in the IL1‐RA (9.02 ± 0.30 mm) as well as significantly increased collagenase activity in the CAR (0.061 ± 0.043) compared to CON (0.027 ± 0.015) (p< 0.05). By histological evaluation, the CAR group demonstrated significantly greater inflammation than IL1‐RA, and CON (p < 0.05). CAR showed a trend for increased cross‐sectional area relative to CON that was absent in the IL1‐RA. IL1‐RA can effectively inhibit the development of mechanical, chemical, and histologic changes seen with carrageenan‐induced tendonitis. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:616–622, 2016.