Bone Shortening After Amputation: A Report of Two Cases.

We report two cases of shortening of the bone at the stump after amputation. Case 1 was a 57-year-old male with a traumatic transhumeral amputation. The remaining humerus had shortened by 3.5 cm in eight months. Case 2 was a 27-year-old male with a traumatic transtibial amputation. The remaining tibia had shortened by 1.4 cm in 72 months. These two cases had the same cause of amputation, but the amputation site, age, and time course differed. Few studies have examined the bone length of stumps after amputation. The bone length of stumps is generally assumed to not change after amputation. However, the residual bone at the stump can shorten after amputation.

New body surface indexes for germinal matrix: DIP joint extension boundary line and dorsal distal interphalangeal crease.

BACKGROUND: Knowledge of the proximal edge of the germinal matrix is essential to avoid injuries in the germinal matrix. The previous index such as terminal tendon insertion is not visible from the body surface. The purpose of this study was to examine the relationship between the proximal edge of the germinal matrix and the body surface indexes by ultrasonographic measurements. METHODS: All participants underwent X-rays of the hand and were grouped based on the presence or absence of osteoarthritis in the distal interphalangeal (DIP) joint. The distance from the proximal edge of the germinal matrix to dorsal distal interphalangeal crease (parameter D1), and to ''DIP joint extension boundary line'' (parameter D2) were measured using ultrasonography. RESULTS: Thirty middle fingers of 24 patients were enrolled; 13 fingers were in control group and 17 fingers were in Heberden's node group. The average of parameter D1 was 6.17 mm (SD 1.12) in the control group (N = 13), and was 7.04 mm (SD 1.31) in Heberden's node group (N = 17) without significant difference. The DIP joint extension boundary line was not visible in 7 fingers with severe DIP joint osteoarthritis. The average of parameter D2 was 0.00 mm (SD 0.00) in the control group (N = 13), and was 0.04 mm (SD 0.13) in Heberden's node group (N = 10). CONCLUSIONS: We suggest that DIP joint extension boundary line and dorsal distal interphalangeal crease are valuable indexes to predict the proximal edge of the germinal matrix from the body surface. Though the DIP joint extension boundary line was not visible in some cases, once it has been sighted, the line shows where the germinal matrix exactly is.

Risk factors for residual pain after ligament reconstruction and tendon interposition on osteoarthritis of the first carpometacarpal joint.

BACKGROUND: Ligament reconstruction and tendon interposition (LRTI) is currently the most performed procedure for osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint. In general, satisfactory outcomes are expected, although some patients complain of residual pain after LRTI. The objective of this study is to determine the factors associated with residual pain. METHOD: All patients with OA of the thumb CMC joint who underwent LRTI at our hospital between October 2013 and October 2018 and were regularly observed for at least 1 year were included. The following variables were extracted and included in the univariate analysis: sex, age, dominant hand, pain visual analog scale (VAS) score, Eaton classification, grip strength, pulp pinch strength, and metacarpophalangeal joint hyperextension angle were recorded as variables. Mann-Whitney U test or Fisher exact test was used for univariate analysis of the above factors, and then multivariate logistic regression analysis was performed to find out the factors associated with residual pain. RESULTS: The study included 60 thumbs of 53 patients. Eleven thumbs had postoperative residual pain. The surgery on the dominant hand was significantly associated with the presence of postoperative residual pain, especially in males. CONCLUSIONS: Dominant hand was associated with residual pain after LRTI for OA of the thumb CMC joint, although residual pain was minimal. Our findings will help in preoperative and postoperative counseling of patients. In the future, our results may also help select surgical procedures according to the patient's characteristics.

Effect of Early vs Delayed Surgical Treatment on Motor Recovery in Incomplete Cervical Spinal Cord Injury With Preexisting Cervical Stenosis: A Randomized Clinical Trial.

Importance: The optimal management for acute traumatic cervical spinal cord injury (SCI) is unknown. Objective: To determine whether early surgical decompression results in better motor recovery than delayed surgical treatment in patients with acute traumatic incomplete cervical SCI associated with preexisting canal stenosis but without bone injury. Design, Setting, and Participants: This multicenter randomized clinical trial was conducted in 43 tertiary referral centers in Japan from December 2011 through November 2019. Patients aged 20 to 79 years with motor-incomplete cervical SCI with preexisting canal stenosis (American Spinal Injury Association [ASIA] Impairment Scale C; without fracture or dislocation) were included. Data were analyzed from September to November 2020. Interventions: Patients were randomized to undergo surgical treatment within 24 hours after admission or delayed surgical treatment after at least 2 weeks of conservative treatment. Main Outcomes and Measures: The primary end points were improvement in the mean ASIA motor score, total score of the spinal cord independence measure, and the proportion of patients able to walk independently at 1 year after injury. Results: Among 72 randomized patients, 70 patients (mean [SD] age, 65.1 [9.4] years; age range, 41-79 years; 5 [7%] women and 65 [93%] men) were included in the full analysis population (37 patients assigned to early surgical treatment and 33 patients assigned to delayed surgical treatment). Of these, 56 patients (80%) had data available for at least 1 primary outcome at 1 year. There was no significant difference among primary end points for the early surgical treatment group compared with the delayed surgical treatment group (mean [SD] change in ASIA motor score, 53.7 [14.7] vs 48.5 [19.1]; difference, 5.2; 95% CI, -4.2 to 14.5; P = .27; mean [SD] SCIM total score, 77.9 [22.7] vs 71.3 [27.3]; P = .34; able to walk independently, 21 of 30 patients [70.0%] vs 16 of 26 patients [61.5%]; P = .51). A mixed-design analysis of variance revealed a significant difference in the mean change in ASIA motor scores between the groups (F1,49 = 4.80; P = .03). The early surgical treatment group, compared with the delayed surgical treatment group, had greater motor scores than the delayed surgical treatment group at 2 weeks (mean [SD] score, 34.2 [18.8] vs 18.9 [20.9]), 3 months (mean [SD] score, 49.1 [15.1] vs 37.2 [20.9]), and 6 months (mean [SD] score, 51.5 [13.9] vs 41.3 [23.4]) after injury. Adverse events were common in both groups (eg, worsening of paralysis, 6 patients vs 6 patients; death, 3 patients vs 3 patients). Conclusions and Relevance: These findings suggest that among patients with cervical SCI, early surgical treatment produced similar motor regain at 1 year after injury as delayed surgical treatment but showed accelerated recovery within the first 6 months. These exploratory results suggest that early surgical treatment leads to faster neurological recovery, which requires further validation. Trial Registration: ClinicalTrials.gov Identifier: NCT01485458; umin.ac.jp/ctr Identifier: UMIN000006780.

Evaluation of the first annular pulley stretch effect under isometric contraction of the flexor tendon in healthy volunteers and trigger finger patients using ultrasonography.

BACKGROUND: Isometric exercises for a flexed finger have been reported to be effective for treating trigger finger as the flexor tendon widens the space under the first annular (A1) pulley towards the palmar destination during the exercise. This study aimed to evaluate the structural changes during the A1 pulley stretch in healthy volunteers and patients with trigger finger using ultrasonography. METHODS: We enrolled 25 male and 14 female patients (39 middle fingers). The thickness of the subcutaneous tissue (parameter a), A1 pulley (parameter b), and the flexor tendon (parameter c) and the distance between the dorsal surface of the flexor tendon and the palmar surface of the metacarpal head (parameter d) were measured using ultrasonography of the metacarpophalangeal joint of the middle finger flexed at 45° at rest (pattern A) and under isometric contraction of the flexor tendon against an extension force of the proximal interphalangeal joint (pattern B). RESULTS: The average differences between patterns A and B in the healthy volunteers were 0.29 mm (parameter a; P = 0.02), 0.017 mm (parameter b; P = 0.63), 0.16 (parameter c; P = 0.26), and 0.41 (parameter d; P = 0.004), and those in patients with trigger finger were 0.22 mm (parameter a; P = 0.23), 0.019 mm (parameter b; P = 0.85), 0.03 mm (parameter c; P = 0.82), and 0.78 mm (parameter d; P < 0.001). The distance between the dorsal side of the A1 pulley and the palmar surface of the metacarpal head was also significantly increased by 0.57 mm (8.2%) in healthy volunteers (P < 0.001) and 0.81 mm (11%) in patients with trigger finger (P < 0.001). CONCLUSIONS: In this study, the space under the A1 pulley was expanded under isometric contraction of the flexor tendon. These findings support the effectiveness of pulley stretch exercises for the trigger finger condition.

Factors Associated With Surgical Intervention for Osteoarthritis of the Thumb Carpometacarpal Joint.

PURPOSE: This retrospective study aimed to analyze the initial clinical factors associated with surgical intervention for osteoarthritis of the thumb carpometacarpal (CMC) joint. METHODS: The study included patients who first visited our hand surgery clinic, were given the diagnosis of osteoarthritis of the thumb CMC joint between May 2012 and January 2015, and were observed for more than 3 years. Patients were classified into 2 groups according to whether they had undergone surgery during the follow-up period. The following variables were extracted and included in a bivariate analysis: sex, age, age at onset, disease duration, dominant hand, pain visual analog scale (VAS) scores at rest and during use, night pain, Eaton classification, use of an orthosis, number of injections, tender area, range of motion, grip strength, pinch strength, Kapandji abduction index, palmar abduction distance, grind test results, CMC joint shape on radiographs, dorsal subluxation ratio, volar tilt of the metacarpal, presence or absence of ossicles, and the surgeon who recommended the surgery. Variables with P values less than .05 in the bivariate analysis were included in a logistic regression model. RESULTS: The study included 80 thumbs of 48 patients. Pain scores at rest and during use, and the dorsal subluxation ratio were identified as factors significantly associated with surgical intervention in the bivariate analysis. The subsequent logistic regression analysis including these factors as explanatory variables also identified the VAS score at rest and dorsal subluxation ratio as significantly associated with surgical intervention. CONCLUSIONS: The VAS score at rest and the dorsal subluxation ratio at the first clinical visit were associated with the likelihood of future surgical intervention within 3 years in patients with osteoarthritis of the thumb CMC joint. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Development of a patient-oriented outcome measure for patients with hand and elbow disorder: HandQ.

PURPOSE: The Disabilities of the Arm, Shoulder, and Hand (DASH) is the most widely used patient-oriented outcome measure for the upper extremities in the world, and high reliability and validity of it has already been confirmed. However, there are several problems with using the DASH, some of which are culturally related. We aimed to (1) develop a patient-oriented disease-specific outcome measure for patients with disorders of the hand and elbow, which we call the HandQ and (2) examine the practical applicability, reliability, and validity of the HandQ for any patient with disorders of the hand and elbow. METHODS: A total of 216 patients were surveyed with the HandQ, as well as the Hand20 and the DASH to assess psychometric characteristics. RESULTS: There were no considerable floor and ceiling effects regarding the total HandQ score. Test-retest reliability and internal consistency determined using the intraclass correlation coefficient (0.942) and Cronbach's α test (0.961) were excellent. The HandQ was well correlated with the Hand20 and the DASH scores. Scree plot showed unidimensionality of the HandQ, and the graphical model showed the questionnaire items of the HandQ had reasonable correlation among each item. CONCLUSIONS: The HandQ has a sufficient reliability and internal consistency, and an excellent validity, and was shown to be able to be practically applicable in all patients with hand and elbow disorders.

Ultrasonographic Classification of Scapholunate Interosseous Ligament Injury Associated With Distal Radius Fracture.

PURPOSE: Although scapholunate interosseous ligament (SLIL) injury is often associated with distal radius fracture, it is frequently missed in x-rays. The purpose of this study was to develop a diagnostic classification based on ultrasonography for SLIL injury and evaluate its diagnostic accuracy. METHODS: Patients who required surgery for distal radius fracture were included in this study. Ultrasonography and arthroscopy were performed in all patients. The original ultrasonography-based classification of the dorsal part of SLIL was developed as follows: for type A, the SLIL surface was outlined clearly as a continuous flat line; for type B, the SLIL surface was outlined clearly as a continuous bulged line; and for type C, the SLIL surface was not continuous, smooth, or outlined clearly. Arthroscopy was performed at the time of osteosynthesis. We classified its findings according to the arthroscopic classification system of Geissler et al and evaluated interobserver and intraobserver reliabilities for our classification on ultrasonography. We also studied the relationship between the ultrasonographic and arthroscopic classifications. RESULTS: In total, 40 patients were included in this study. Weighted κ values for interobserver and intraobserver reliabilities for our ultrasonographic classification were 0.83 (95% confidence interval, 0.70-0.96) and 0.88 (95% confidence interval, 0.77-0.99), respectively. There were 17 patients with type A, 14 with type B, and 9 with type C on ultrasonography. Ultrasonography had a sensitivity of 64% and specificity of 93% for the assumption that type C on ultrasonography corresponded to Geissler grades 3 and 4 on arthroscopy. No patient with type A on ultrasonography was classified as Geissler grades 3 and 4 on arthroscopy. CONCLUSIONS: We concluded that ultrasonography has a high specificity but low sensitivity for the diagnosis of SLIL injury. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic Ⅱ.

Assessment of Dorsal Subluxation in Thumb Carpometacarpal Osteoarthritis.

Background Although dorsal subluxation is a typical finding for osteoarthritis of the thumb carpometacarpal (CMC) joint, it is difficult to evaluate the subluxation after trapeziectomy and the significance of its surgical correction combined with trapeziectomy is still controversial. The purpose of this study was to develop a method to evaluate dorsal subluxation without using landmarks on the trapezium. Methods Thirty patients with thumb CMC arthritis and 13 normal patients were included in this study. Dorsal subluxation of the CMC joint was evaluated by measuring the distance between the volar tip of the thumb metacarpal base and dorsoradial border of the index metacarpal base (M1M2 overlap) on the X-ray true lateral view of the thumb as well as previously reported methods. Intraclass correlation coefficient (ICC) was used to assess inter- and intraobserver reliability for the measurement of M1M2 overlap by six examiners of different level of expertise. Dorsal subluxation was also evaluated after trapeziectomy with ligament reconstruction. Results There were almost perfect interobserver (ICC = 0.94) and intraobserver (ICC = 0.95 for an expert and 0.97 for a novice) reliabilities for the measurement of M1M2 overlap. There was a weak correlation between our method and previously reported methods. M1M2 overlap of the normal patients and the patients were 4.6 ± 1.2 mm and 2.3 ± 2.3 mm (mean ± SD), respectively. M1M2 overlap was corrected significantly after trapeziectomy with ligament reconstruction. Conclusion Dorsal subluxation of the thumb CMC joint could be evaluated by M1M2 overlap before and after trapeziectomy.

Insufficiency Fractures of the Distal Tibia and Fibula Following Total Hip Arthroplasty: A Case Report.

INTRODUCTION: Although periprosthetic fractures of the femur have been well documented, insufficiency fractures following total hip arthroplasty (THA) have been rarely described. We report a case of an insufficiency fracture in the distal tibia and fibula that occurred after THA. CASE REPORT: A 54-year-old woman presented with severe pain in the bilateral hip joints and was diagnosed with end-stage osteoarthritis. She underwent THA on the right side. Although the postoperative course was uneventful, she suddenly experienced severe pain and swelling in the right leg without any history of trauma 22 weeks after the surgery. She was first diagnosed with cellulitis by her local doctor and was treated with oral antibiotics. Her symptoms persisted, and she returned to our hospital 1 month later. Her right distal leg and ankle were diffusely swollen and tender. Plain radiographs revealed a sclerotic linear zone in the distal tibia and fibula. She was diagnosed with insufficiency fractures in the distal tibia and fibula following THA. Local disuse osteoporosis and increased mechanical stress after THA as a result of pain relief could be the causes for her fracture. Her right leg and ankle were immobilized with a splint for another 4 weeks. Her symptoms subsided gradually, and fracture union was confirmed on the follow-up X-ray. CONCLUSION: Insufficiency fractures should be suspected in patients complaining of unexplainable pain, even in the distant area of the affected limb, for at least 6 months following THA.

Improvement of walking ability during postoperative rehabilitation with the hybrid assistive limb after total knee arthroplasty: A randomized controlled study.

OBJECTIVE: We aimed to compare the efficacies of rehabilitation with the hybrid assistive limb and conventional rehabilitation after total knee arthroplasty. MATERIALS AND METHODS: A total of 37 consecutive patients who underwent primary total knee arthroplasty for knee osteoarthritis were enrolled. Seven patients withdrew from the study after randomization, and 30 patients (hybrid assistive limb group: n = 16; conventional group: n = 14) completed the randomized controlled trial. Patients in the hybrid assistive limb group underwent ten 20-min rehabilitation sessions with the hybrid assistive limb as well as 20-min conventional sessions over the course of 2 weeks, whereas patients in the conventional group received ten 40-min conventional sessions during the same period. The primary outcome measure was walking speed, whereas the secondary outcome measures included quadriceps strength and knee pain assessed using a numerical rating scale. The outcome measures were evaluated prior to surgery and on postoperative weeks 1, 2, and 3. RESULTS: In the early postoperative period, rehabilitation after total knee arthroplasty with the hybrid assistive limb resulted in a significantly greater improvement in walking speed (weeks 1 and 2: p = 0.045), quadriceps strength (weeks 1 and 2; weeks 1 and 3: p < 0.0001), and numerical rating scale scores (week 1: p = 0.03) than conventional rehabilitation. CONCLUSION: Rehabilitation with the hybrid assistive limb after total knee arthroplasty led to greater improvements in walking speed, quadriceps strength, and pain scores than conventional rehabilitation.

Extension block pinning using a small external fixator for mallet finger fractures.

PURPOSE: To describe surgical outcomes of a series of patients with bony mallet fingers treated by a modified extension blocking technique with external fixation. METHODS: We developed an external fixator that was attached to the extension block pin. Dorsal rotation of the dorsal fragment during reduction was prevented with 1 or 2 additional pins abutted on the fragment through the fixator. We reviewed 12 consecutive patients with mallet finger fractures who were treated surgically with the external fixator. The mean age of the patients was 33 years (range, 15-60 y). RESULTS: Rotation of the fragment during reduction was well controlled in all patients. All fractures united at an average of 5 weeks after surgery. Average extension lag was 2° and active flexion was 74°. No patient reported pain at a final follow-up of 4 months (range, 3-8 mo). According to the Crawford rating scale, 10 patients were classified as excellent and 2 were good. CONCLUSIONS: Our modification of the extension block method prevented dorsal rotation of the fragment during reduction and resulted in early union. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Comparative study on the stiffness of transverse carpal ligament between normal subjects and carpal tunnel syndrome patients.

The purpose of this study was to compare the stiffness of the transverse carpal ligament (TCL) between healthy volunteers and carpal tunnel syndrome (CTS) patients using sonoelastography. We studied 17 healthy volunteers (four men, 13 women; range 37-84 years) and 18 hands of 13 patients with CTS (three men, ten women; range 41-79 years). Thickness and elasticity of the TCL were evaluated by sonoelastography. Elasticity was estimated by strain ratio of an acoustic coupler, which has a standardized elasticity as a reference medium, to the TCL (AC/T strain ratio). The AC/T strain ratios of the healthy volunteers and the CTS patients were 6.0 and 8.1, respectively (p = 0.030). The AC/T strain ratio showed a positive correlation with the duration of symptoms in the CTS patients (p = 0.035, r = 0.50). We concluded that increased stiffness of the TCL could be one of the causes for CTS.

Ultrasonographic evaluation of displaced neurovascular bundle in Dupuytren disease.

PURPOSE: Neurovascular injury is a serious complication after surgery for Dupuytren disease. The purpose of this study was to evaluate the relationship between the cord and the neurovascular bundle ultrasonographically. METHODS: We included 22 healthy volunteers and 14 Dupuytren disease patients (25 fingers) in this study. We evaluated the cord and the digital artery with high-resolution ultrasound. We first investigated the effect of the angle of metacarpophalangeal joint on the position of the radial and ulnar digital arteries in volunteers without evidence of Dupuytren disease. We compared 3 parameters of the radial and ulnar digital arteries, including differences in depth, differences in lateral shift, and the shape of the cross-section of the artery, between volunteers and patients with Dupuytren disease. RESULTS: None of these parameters changed with flexion of the metacarpophalangeal joint of 0°, 30°, and 60°. Digital arteries and cords could be identified ultrasonographically in all patients, and we confirmed ultrasonographic findings by operative findings in 13 fingers. We classified the fingers into 3 subgroups based on the ultrasonographic findings: type A (n = 13), in which the cord was above the artery; type B (n = 5), in which the cord was below the artery; and type C (n = 7), in which the cord was located between the radial and ulnar digital arteries. Types A, B, and C corresponded to natatory cord/abductor digiti minimi cord, spiral cord, and central cord, respectively. Comparisons among volunteers and patient subgroups showed that the difference in depth in type B patients was significantly larger than that of the other groups. When we set the cutoff point of the difference in depth to 3 mm, sensitivity and specificity to detect the spiral cord were 80% and 76%, respectively. CONCLUSIONS: The relationship between the neurovascular bundle and the type of Dupuytren disease cord can be evaluated by high-resolution ultrasound. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.

Fungal arthritis of the wrist caused by Candida parapsilosis during infliximab therapy for rheumatoid arthritis.

A 60-year-old woman with rheumatoid arthritis, who had been treated with infliximab, presented with uncontrollable wrist arthritis. Fungal arthritis caused by Candida parapsilosis was confirmed by examining her aspirated joint fluid. Her infliximab therapy was interrupted, and antifungal therapy with fluconazole was started. After the fungal infection had been ameliorated, surgical debridement and arthrodesis of the wrist joint were conducted, and her symptoms completely resolved. Although fungal arthritis is rare, it should be considered as a differential diagnosis of exacerbated monoarthritis in patients treated with biological agents.

Stiffness of the first annular pulley in normal and trigger fingers.

PURPOSE: The cause of snapping in trigger finger is not clearly understood. The purpose of this study was to investigate the influence of stiffness of the first annular pulley on snapping in trigger finger patients with sonoelastography, a new technique for quantitative assessment of the stiffness of soft tissues. METHODS: We first studied 20 healthy volunteers (all women, aged 24-78 y) to define the change of stiffness with aging and with specific fingers. We then studied 10 digits of 9 patients (all women, aged 60-78 y) with trigger finger that involved middle or ring fingers. Thickness and stiffness were evaluated by sonoelastography. Stiffness was estimated by strain ratio of subcutaneous fat to the pulley (F/P strain ratio). The patients were treated with corticosteroid injection, and the measurement was repeated 3 weeks later. RESULTS: In the healthy volunteers, both thickness and F/P strain ratio showed a positive correlation with age. There was no difference between the middle and ring fingers. In trigger finger patients, the pulley thicknesses of the affected finger and the adjacent normal finger before corticosteroid injection were 0.99 ± 0.19 mm and 0.60 ± 0.14 mm (mean ± SD), respectively. The F/P strain ratios of the affected finger and the adjacent normal finger before the injection were 4.2 ± 1.3 and 2.4 ± 0.63, respectively. Three weeks after the injection, snapping disappeared in all patients, the pulley thickness decreased to 0.61 ± 0.15 mm, and the F/P strain ratio decreased to 2.5 ± 0.68. The cross-sectional area for flexor tendons within the pulley did not change after the injection. CONCLUSIONS: Increased stiffness and thickening of the A1 pulley are considered to be causes for snapping in trigger finger, and corticosteroid injection can alleviate snapping by changing these 2 features.

Reduction of Peritendinous adhesions by hydrogel containing biocompatible phospholipid polymer MPC for tendon repair.

BACKGROUND: Peritendinous adhesions are serious complications after surgical repair of tendons. As an anti-adhesion material, we focused on 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, our original biocompatible polymer, and prepared an aqueous solution of MPC-containing polymer called poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate-co-p-vinylphenylboronic acid) (PMBV), which can be formed into hydrogel properties by mixture with another aqueous polymer, poly(vinyl alcohol) (PVA). The objective of the present study was to examine the possible application of the MPC hydrogel for the reduction of peritendinous adhesions. METHODS: the effects of the hydrogel on peritendinous adhesions and tendon healing were examined by means of histological and mechanical analyses in a rat Achilles tendon model and a rabbit flexor digitorum profundus tendon model. Cell migration and viability were examined with use of fibroblastic NIH3T3 cells cultured in a double chamber dish. RESULTS: among the concentrations examined, 2.5% and 5.0% PMBV formed hydrogel properties immediately after mixing with 2.5% PVA and maintained a honeycomb microstructure with nanometer-scaled pores for three weeks after implantation. In animal models, the hydrogel formed from 5.0% PMBV remained at the sutured site during the critical period up to three weeks and disappeared by six weeks. The MPC hydrogel reduced the peritendinous adhesions histologically and mechanically by >25% at three weeks, without impairing tendon healing as determined with mechanical analyses. In the cell culture, cell migration was reduced by the MPC hydrogel, although cell viability was unaffected, indicating physical prevention, rather than cytotoxicity, to be the anti-adhesion mechanism. CONCLUSIONS: the MPC hydrogel that was formed by a local injection and mixture of two aqueous solutions, 5.0% PMBV and 2.5% PVA, reduced peritendinous adhesions without impairing tendon healing. This effect may be due to its excellent biocompatibility without a foreign-body reaction and the formation of a microstructure that physically prevents passage of cells but allows cytokines and growth factors to pass for healing. CLINICAL RELEVANCE: this nanotechnology could potentially improve the quality of surgical repair of tendon, especially the zone-II area of the digital flexor tendon.

Anatomical placement of double femoral tunnels in anterior cruciate ligament reconstruction: anteromedial tunnel first or posterolateral tunnel first?

PURPOSE: The purpose of this study was to know which tunnel--the anteromedial (AM) bundle or the posterolateral (PL) bundle--should be prepared first to create the 2 femoral tunnels accurately in anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. METHODS: Thirty-four patients were divided into 2 groups of 17 depending on the sequence of preparation of the 2 femoral tunnels. In group A, the AM tunnel was prepared first, whereas the PL tunnel was prepared first in group P. ACL reconstruction was performed using a three-dimensional (3-D) fluoroscopy-based navigation system to place the double femoral tunnels through an accessory medial portal. The double femoral socket positioning was evaluated by 3-D computed tomography (CT) scan image. RESULTS: The non-anatomical placement of the femoral sockets occurred in 5 patients (29%) in group A, whereas the 2 sockets were placed anatomically in all patients in group P (P < 0.05). Evaluation of the AM and the PL socket location on the 3-D CT images using the quadrant method showed more similar values to the laboratory data in a literature in group P than in group A. No complication occurred in group A, whereas complications such as socket communications or back wall blowout occurred in 5 patients (29%) in group P (P < 0.05). CONCLUSION: The sequence of creating 2 femoral tunnels through accessory medial portal affected the resultant location of the sockets and the rate of the complications. When femoral tunnels are prepared with a transportal technique, PL tunnel first technique seems to be superior to AM first technique regarding anatomic placement. However, PL tunnel first technique accompanies the risk of socket communication.