Cheng Li Lin

Treatment of unstable distal clavicle fractures with Knowles pin

BACKGROUNDnUnstable distal clavicle fractures often need surgical treatment. This report describes a new intramedullary extra-articular Knowles pin fixation method to treat these unstable fractures.nnnMATERIALS AND METHODSnTwelve patients with unstable distal clavicle fractures (Neer type II) had surgery with intramedullary extra-articular Knowles pin fixation. We retrospectively reviewed clinical results for pain, shoulder function, and range of motion, as well as radiographic results, for this institutional review board-approved study. Each patients operated arm was in a sling for 4 weeks postoperatively. The University of California, Los Angeles shoulder rating scale score was used to evaluate shoulder function.nnnRESULTSnAll patients showed radiographically confirmed bony union. The mean period required for healing was 11.5 weeks, and patients were followed up for 6 to 24 months (mean, 15.2 months), during which University of California, Los Angeles scores (mean, 33.9) indicated good clinical results. Three patients had the complication of proximal or distal skin irritation caused by the thread and hub of the Knowles pin.nnnCONCLUSIONSnThe Knowles pin fixation method is useful for treating unstable distal clavicle fractures. However, sufficient familiarity with the technique and careful preoperative planning to determine the appropriate length of the pin are necessary to prevent complications and to effect a high union rate.

Biomechanical Study Comparing Biceps Wedge Tenodesis With Other Proximal Long Head of the Biceps Tenodesis Techniques

PURPOSEnThe purpose of this biomechanical study was to compare the ultimate failure strength, stiffness, cyclic displacement, and failure displacement of 5 different proximal biceps tenodesis fixation techniques, specifically comparing wedge tenodesis with the other 4 techniques.nnnMETHODSnForty cadaveric shoulders underwent 1 of 5 long head of the biceps tenodesis techniques and were cyclically tested to failure by use of tensile forces applied parallel to the longitudinal axis of the humerus. A preload at 5 N was applied for 2 minutes, followed by cyclical loading for 500 cycles from 5 to 70 N at 1 Hz and a pull-to-failure test at 1 mm/s. The techniques studied were wedge tenodesis, suture anchor fixation, suprapectoral interference screw fixation, T-wedge tenodesis, and the percutaneous intra-articular transtendon (PITT) technique. Cyclic displacement, failure displacement, and stiffness were calculated.nnnRESULTSnThe wedge tenodesis technique had an ultimate failure load similar to interference screw fixation and a greater ultimate failure load and stiffness than the suture anchor, PITT, and T-wedge techniques (P < .05).nnnCONCLUSIONSnIn this biomechanical study, wedge tenodesis was found to have an ultimate failure load similar to interference screw fixation and a greater ultimate failure load and stiffness than the suture anchor, PITT, and T-wedge techniques.nnnCLINICAL RELEVANCEnOn biomechanical testing, wedge tenodesis compares favorably with other techniques and may be a useful clinical option for proximal biceps tenodesis.

Fracture risk and correlating factors of a pediatric population with attention deficit hyperactivity disorder: A nationwide matched study

The aim of this study was to investigate the risk of fracture and the difference between sexes from a nationwide database of fracture risk among children aged 4–17 years with or without attention deficit hyperactivity disorder (ADHD, ICD-9-CD codes 314). The Longitudinal Health Insurance Database (LHID 2000) was used to analyze fracture characteristics of children from the National Health Insurance that covered 96.1% of the Taiwanese population (N=21.4 million). A total of 7200 ADHD children aged between 4 and 17 years whose diagnosis had been confirmed in at least three outpatient clinics between 1 January 2000 and 31 December 2009 were included, and a cohort of 36u2009000 children without ADHD matched for age, sex, and urbanization was recruited for analysis. The incidence rate of fractures in ADHD children was 21.0 (95% confidence interval=19.4–22.7) per 1000 person-years, significantly (P<0.001) higher than 15.0 (95% confidence interval=14.4–15.6) in non-ADHDs. After adjusting by age, sex, urbanization level, and geographic region, the statistically significant (P<0.001) hazard ratios (HR) of fracture for ADHD children compared with non-ADHD children included 1.62 in girls and 1.38 in boys, 1.53 in the skull, neck, and trunk (ICD-9-CM 800–809), 1.28 in the upper extremity (ICD-9-CM 810–819), and 1.84 in the lower extremity (ICD-9-CM 820–829). The HR also (P<0.001) increased significantly in all age groups, including 1.35 in 4–6, 1.37 in 7–9, and 1.54 in 10–17 years. ADHD should be listed among risk factors of children’s fractures in each sex, all age groups, and all body areas that the parents, teachers, caregivers of ADHD children, and pediatric orthopedists should be aware of. Besides, ADHD girls were more affected than ADHD boys, especially after 10 years of age, whereas the adjusted HR was the highest in the lower extremities. Nationwide analysis matched for age and sex showed that ADHD should be considered the risk factor of children’s fracture, especially for girls older than 10 years of age.

Fracture of VerSys fully bead-coated long femoral stems: Report on four fractures in 41 hips

The fracture of uncemented, fully porous, coated femoral stems is a rare complication that develops after primary total hip arthroplasty, and it is even rarer after revision surgery. To the best of our knowledge, cases of only 10 broken fully coated stems have been reported. This is the first report on fracture of the VerSys fully bead‐coated femoral stem, which is designed for diaphyseal fixation and for application in revision surgery or when a proximal fixation is not feasible. Between 2000 and 2008, we implanted 41 VerSys fully coated stems in 40 patients. We present four cases of femoral stem fractures at 23, 31, 40, and 86 months after surgery. The common risk factors for these four patients were inadequate support for the implant in the proximal femur due to nonunion in this area, a stem diameter ≤12u2009mm, and a relatively young age.

Snapping hip caused by a venous hemangioma of the gluteus maximus muscle: A case report

IntroductionSnapping hip, or coxa saltans, is defined as a clinical condition where a usually painful, audible snap occurs during hip flexion and extension. Its causes can be divided into external, internal or intra-articular origin. Accurate diagnosis is a prerequisite to successful treatment. We report a rare cause of snapping hip which is different from any previously reported cases.Case presentationA 23-year-old man presented to us with right hip pain of more than 10 years duration. Atrophy of the right gluteus maximus with snapping and tenderness were also noted. The imaging study revealed a focal intramuscular lesion in the lateral portion of the right gluteus maximus muscle. Surgery was performed and pathological examination concluded this mass to be a venous hemangioma.ConclusionIntramuscular hemangioma, though rare, should be considered in the differential diagnosis of a snapping hip even though muscle fibrosis is most frequently encountered.

Mesh Achilles tendon lengthening--a new method to treat equinus deformity in patients with spastic cerebral palsy: surgical technique and early results.

Equinus of the ankle is a common deformity in spastic cerebral palsy. Many methods have been developed to lengthen the Achilles tendon to correct the deformity. A new mesh Achilles tendon lengthening (ATL) procedure that might decrease immobilization and promote recovery was performed in 36 tendons with equinus deformity (22 patients, average age=6.2). The results were compared with those of two other methods: the Vulpius group and the Z-lengthening group. The corrected dorsiflexion angle of the ankle at a subsequent 2-year follow-up of the mesh ATL and Vulpius groups matched (25.5±3.0 and 27.1±3.5°, respectively), whereas that of the Z-lengthening group was higher (33.9±3.8°). Nevertheless, statistics of the timing of each patient’s readiness to begin rehabilitation and walking as well as gaining better stability for running and one-legged hopping indicated that the mesh ATL group recovered significantly quicker than the Vulpius and Z-lengthening groups. The mesh ATL procedure achieves a successful correction of the equinus deformity in spastic cerebral palsy comparable with that of the Vulpius procedure, with the advantage of preserving the gastrocnemius without a complete section. This confers greater antigravity stability and quicker recovery in patients.

Biomechanical Evaluation of a Transtendinous All-Suture Anchor Technique versus Interference Screw Technique for Suprapectoral Biceps Tenodesis in a Cadaveric Model

PURPOSEnTo compare the biomechanical properties of an transtendinous all-suture anchor technique with the commonly-accepted interference screw technique in a cadaveric model.nnnMETHODSnSixteen fresh-frozen human cadaveric shoulders (mean age, 67.6 ± 5.8xa0years) were used and were randomly divided into 2 experimental long head of the biceps brachii (LHB) tenodesis groups (nxa0= 8), namely transtendinous all-suture anchor technique and interference screw technique. The location of tenodesis was in the bicipital groove, 1xa0cm distal to the proximal border of the bicipital groove. Tensile force parallel to the longitudinal axis of the humerus was applied to each specimen. A preload of 5xa0N was applied for 2xa0minutes, followed by cyclic loading for 500 cycles from 5 to 70xa0N at 1xa0Hz; then, a load-to-failure test at 1xa0mm/s was performed. The ultimate failure load, stiffness, cyclic displacement, failure displacement, and failure modes were recorded.nnnRESULTSnThe transtendinous all-suture anchor technique provided similar ultimate failure load and stiffness as the interference screw technique. However, the cyclic and failure displacements of the transtendinous all-suture anchor technique were significantly greater than the interference screw technique (Pxa0= .009 and .021, respectively). Six specimens in the transtendinous all-suture anchor group failed because of suture anchor pullout, while failure of the other 2xa0was caused by tendon tear; by contrast, all specimens in the interference screw group failed because of tendon tear.nnnCONCLUSIONSnThe transtendinous all-suture anchor technique for LHB tenodesis offered equivalent ultimate failure load and stiffness but had significantly larger cyclic and failure displacement values when compared with the interference screw technique in this cadaveric biomechanical study.nnnCLINICAL RELEVANCEnThe transtendinous all-suture anchor technique is an alternative technique for suprapectoral LHB tenodesis; however, care should be taken because only time zero biomechanical data are available.

A Biomechanical Evaluation of Various Double Krackow Suture Techniques for Soft-Tissue Graft Fixation

PURPOSEnThe purpose of this study was to compare the biomechanical properties among the different double Krackow suture techniques for tendon graft fixation.nnnMETHODSnThirty porcine flexor profundus tendons were randomly divided into 3 groups of 10 specimens each. Three different double Krackow suture techniques were evaluated, namely, the McKeons double Krackow (MDK) suture, Wilsons double Krackow (WDK) suture, and Ostranders modified Krackow (OMK) suture. All suture configurations were completed with a braided nonabsorbable suture. Each suture-tendon construct was pretensioned to 100xa0N for 3 cycles, cyclically loaded from 50 to 200xa0N for 200 cycles, and then finally loaded to failure. Elongation after cyclic loading, ultimate load to failure, and the mode of failure were recorded for each specimen.nnnRESULTSnThere were significant differences in elongation after cyclic loading among the MDK suture (7.9 ± 3.6xa0mm, 14%xa0± 6%), WDK suture (11.6 ± 2.2xa0mm, 22% ± 3%), and OMK suture (9.6 ± 3.3xa0mm, 17% ± 6%; Pxa0= .018). In addition, although the post hoc analysis showed that elongation after cyclic loading in the MDK suture was significantly less than the WDK suture (Pxa0= .004), ultimate failure load and cross-sectional area were not significantly different across the 3 groups.nnnCONCLUSIONSnIn this porcine inxa0vitro biomechanical study, the MDK suture had significantly smaller elongation after cyclic loading than the WDK suture; however, high elongation values may have a potential for risk of clinical laxity. The ultimate failure load was not different across the MDK, WDK, and OMK sutures.nnnCLINICAL RELEVANCEnSmaller elongation during cyclic loading in a suture-tendon construct represents a lower possibility of tendon graft loosening after ligament reconstruction surgery. The double Krackow suture techniques are attractive options for tendon graft fixation in ligament reconstruction, and the MDK suture could possibly be the optimal choice among the double Krackow suture techniques.

The effect of coracoacromial ligament excision and acromioplasty on the amount of rotator cuff force production necessary to restore intact glenohumeral biomechanics

HYPOTHESIS AND BACKGROUNDnCoracoacromial ligament (CAL) excision and acromioplasty increase superior and anterosuperior glenohumeral translation. It is unknown how much of an increase in rotator cuff force production is required to re-establish intact glenohumeral biomechanics after these surgical procedures. We hypothesized that, after CAL excision and acromioplasty, an increase in rotator cuff force production would not be necessary to reproduce the anterosuperior and superior translations of the intact specimens.nnnMETHODSnNine cadaveric shoulders were subjected to loading in the superior and anterosuperior directions in the intact state after CAL excision, acromioplasty, and recording of the translations. The rotator cuff force was then increased to normalize glenohumeral biomechanics.nnnRESULTSnAfter CAL excision at 150 and 200 N of loading, an increase in the rotator cuff force by 25% decreased anterosuperior translation to the point where there was no significant difference from the intact specimens translation. After acromioplasty (and CAL excision) at 150 and 200 N, an increase in the rotator cuff force of 25% and 30%, respectively, decreased superior translation to the point where there was no significant difference from the intact specimens translation.nnnCONCLUSIONSnAt 150 to 200 N of loading, CAL excision and acromioplasty increase the rotator cuff force required to maintain normal glenohumeral biomechanics by 25% to 30%.nnnCLINICAL RELEVANCEnAfter a subacromial decompression, the rotator cuff has an increased force production requirement to maintain baseline glenohumeral mechanics. Under many circumstances, in vivo force requirements may be even greater after surgical attenuation of the coracoacromial arch.nnnLEVEL OF EVIDENCEnBasic Science Study; Biomechanics.

Could the topping-off technique be the preventive strategy against adjacent segment disease after pedicle screw-based fusion in lumbar degenerative diseases? A systematic review

The “topping-off” technique is a new concept applying dynamic or less rigid fixation such as hybrid stabilization device (HSD) or interspinous process device (IPD) for the purpose of avoiding adjacent segment disease (ASD) proximal to the fusion construct. A systematic review of the literature was performed on the effect of topping-off techniques to prevent or decrease the occurrence of ASD after lumbar fusion surgery. We searched through major online databases, PubMed and MEDLINE, using key words related to “topping-off” technique. We reviewed the surgical results of “topping-off” techniques with either HSD or IPD, including the incidence of ASD at two proximal adjacent levels (index and supra-adjacent level) as compared to the fusion alone group. The results showed that the fusion alone group had statistically higher incidence of radiographic (52.6%) and symptomatic (11.6%) ASD at the index level as well as higher incidence (8.1%) of revision surgery. Besides, the HSD (10.5%) and fusion groups (24.7%) had statistically higher incidences of radiographic ASD at supra-adjacent level than the IPD (1%). The findings suggest that the “topping-off” technique may potentially decrease the occurrence of ASD at the proximal motion segments. However, higher quality prospective randomized trials are required prior to wide clinical application.