Gross and Histological Analysis of Healing After Dog Flexor Tendon Repair with the Teno Fix™ Device

The purpose of this study was to examine the in vivo characteristics of the stainless-steel Teno Fix™ device used for flexor tendon repair. The common flexor digitorum superficialis tendon was transected in 16 dogs and repaired with the device. The animals were euthanized at 3, 6, or 12 weeks postoperatively. Difficulties with cast immobilization led nine of 16 animals to be full weight bearing too early, leading to rupture of their repairs. The seven tendons with successful primary repairs (gap <2 mm) underwent histological examination. This in vivo study demonstrates that use of the Teno Fix™ in “suture” of dog flexor tendons did not lead to scarring at the tendon surface, does not cause an inflammatory reaction within the tendon and does not interfere with tendon healing.

A multicentre cross-sectional study to examine physicians' ability to rule out a distal radius fracture based on clinical findings

Purpose

To study current use of radiography in patients with wrist trauma and examine physicians’ ability to rule out a distal radius fracture based on their physical findings.

Methods

We performed a multicentre cross-sectional observational study in five Emergency Departments (ED) between November 2010 and June 2014 and included all consecutive adult patients with wrist trauma. Physicians were asked to perform a standardized examination of the wrist and to subsequently indicate the probability of a distal radius fracture.

Results

The majority of the 924 included patients were referred for radiography (99.6 %). Of the 920 patients that were imaged, 402 (44 %) had sustained a distal radius fracture, 82 (9 %) an isolated carpal fracture and 12 (1 %) an isolated ulna fracture. Overall, physicians were able to accurately discriminate between patients with and without a distal radius fracture (area under the receiver operating characteristics curve: 0.87, 95 % CI 0.85–0.89). Physicians were absolutely certain of their clinical diagnosis in 180 patients (19 %), for whom they indicated either a 0 % or a 100 % probability. In these patients, physicians showed a 99 % sensitivity (95 % CI 98–100) and 67 % specificity (95 % CI 53–80) for predicting a distal radius fracture.

Conclusions

Although physicians in the ED are able to accurately discriminate between patients with and without a distal radius fracture based on their physical findings, they were only completely certain of their diagnosis in 19 % of the patients. A validated clinical decision rule could reinforce physician’s clinical judgment and support them in their decision not to routinely request radiography.

Transfer of the flexor carpi radialis to the abductor pollicis brevis tendon for the restoration of tip-pinch in severe carpal tunnel syndrome

In patients with severe thenar atrophy secondary to carpal tunnel syndrome, we hypothesize that following open carpal tunnel release, concomitant transfer of the abductor pollicis brevis (APB) origin to the flexor carpi radialis (FCR) tendon will lead to improved patient function restoring palmar abduction and thumb opposition. We evaluated 14 patients through questionnaires and seven patients through additional physical examination (thumb range of motion, ability to tip pinch, grip/pinch strength) for a mean follow-up of 2.8 years. All patients showed evidence of palmar abduction with 71% demonstrating the ability to oppose the thumb to the tip and base of the small finger. The transfer of the APB origin to the FCR tendon can restore thumb abduction and opposition for thenar paralysis secondary to severe carpal tunnel syndrome. Patients experience good functional outcomes with the majority experiencing restored thumb opposition.

The rat model of femur fracture for bone and mineral research: An improved description of expected comminution, quantity of soft callus and incidence of complications

Objectives

One commonly used rat fracture model for bone and mineral research is a closed mid-shaft femur fracture as described by Bonnarens in 1984. Initially, this model was believed to create very reproducible fractures. However, there have been frequent reports of comminution and varying rates of complication. Given the importance of precise anticipation of those characteristics in laboratory research, we aimed to precisely estimate the rate of comminution, its importance and its effect on the amount of soft callus created. Furthermore, we aimed to precisely report the rate of complications such as death and infection.

Methods

We tested a rat model of femoral fracture on 84 rats based on Bonnarens’ original description. We used a proximal approach with trochanterotomy to insert the pin, a drop tower to create the fracture and a high-resolution fluoroscopic imager to detect the comminution. We weighed the soft callus on day seven and compared the soft callus parameters with the comminution status.

Results

The mean operating time was 34.8 minutes (sd 9.8). The fracture was usable (transverse, mid-shaft, without significant comminution and with displacement < 1 mm) in 74 animals (88%). Of these 74 usable fractures, slight comminution was detected in 47 (63%). In 50 animals who underwent callus manipulation, slight comminution (n = 32) was statistically correlated to the amount of early callus created (r = 0.35, p = 0.015). Two complications occurred: one death and one deep infection.

Conclusions

We propose an accurate description of comminution and complications in order to improve experiments on rat femur fracture model in the field of laboratory research.

Cite this article: Bone Joint Res 2013;2:149–54.

Cavernous nerve graft reconstruction during radical prostatectomy or radical cystectomy: safe and technically feasible

High local stage prostate and bladder cancers frequently require wide local resection and sacrifice of one or both cavernous nerves to achieve a negative surgical margin, thus resulting in erectile dysfunction. This is a report on preliminary experience with cavernous nerve graft reconstruction using sural nerve grafts with radical prostatectomy or radical cystectomy.Pre-operative evaluation was performed and consent was obtained in 14 potent men with prostate (11) or bladder (three) cancer. Sural nerve grafts of resected cavernous nerves were performed using a microsurgical technique. Post-operative treatment (Sildenafil or Alprostadil) was pursued until return of spontaneous function, documented by interview and adequate scores (>20) in the erectile function (EF) domain of the International Index of Erectile Function (IIEF).Twelve unilateral nerve grafts were performed, 10 during radical prostatectomy and two during radical cystoprostatectomy. Two procedures were technically not possible because of locally advanced disease. Mean age was 57.5 y (36-68 y). Mean follow up was 16.1 months (7-28 months). Pathological stage of prostate cancer was pT2 in 2, pT3 in 7 and pT4 in one. Surgical margins were positive in five out of 10 (50%), and two (20%%) had positive lymph nodes. Four patients (three post prostatectomy and one post cystectomy) were fully potent. Additionally, one patient post prostatectomy had improving partial erections. Six patients post prostatectomy and one patient post cystectomy had no erections. The only complication was one superficial wound infection in the sural nerve donor site. Preliminary experience shows that sural nerve grafts are feasible and safe after radical prostatectomy and cystectomy. However, candidates usually present with high stage disease, high risk for recurrence and frequent requirement for adjuvant therapy that further compromises erectile function. Randomized studies with more patients and long follow-up periods are necessary in order to define the ideal candidate for nerve graft procedures.

Osteochondral repair of primate knee femoral and patellar articular surfaces: implications for preventing post-traumatic osteoarthritis

The risk of post-traumatic osteoarthritis following an intra-articular fracture is determined to large extent by the success or failure of osteochondral repair. To measure the efficacy of osteochondral repair in a primate and determine if osteochondral repair differs in the patella (PA) and the medial femoral condyle (FC) and if passive motion treatment affects osteochondral repair, we created 3.2 mm diameter 4.0 mm deep osteochondral defects of the articular surfaces of the PA and FC in both knees of twelve skeletally mature cynomolgus monkeys. Defects were treated with intermittent passive motion (IPM) or cast-immobilization (CI) for two weeks, followed by six weeks of ad libitum cage activity. We measured restoration of the articular surface, and the volume, composition, type II collagen concentration and in situ material properties of the repair tissue. The osteochondral repair response restored a mean of 56% of the FC and 34% of the PA articular surfaces and filled a mean of 68% of the chondral and 92% of the osseous defect volumes respectively. FC defect repair produced higher concentrations of hyaline cartilage (FC 83% vs. PA 52% in chondral defects and FC 26% vs. PA 14% in osseous defects) and type II collagen (FC 84% vs. PA 71% in chondral defects and FC 37% vs. PA 9% in osseous defects) than PA repair. IPM did not increase the volume of chondral or osseous repair tissue in PA or FC defects. In both PA and FC defects, IPM stimulated slightly greater expression of type II collagen in chondral repair tissue (IPM 81% vs. CI 74%); and, produced a higher concentration of hyaline repair tissue (IPM 62% vs. CI 42%), but IPM produced poorer restoration of PA articular surfaces (IPM 23% vs. CI 45%). Normal articular cartilage was stiffer, and had a larger Poisson's ratio and less permeability than repair cartilage. Overall Cl treated repair tissue was stiffer and less permeable than IPM treated repair tissue. The stiffness, Poisson's ratio and permeability of femoral condyle cast immobilized (FC CI) treated repair tissue most closely approached the normal values. The differences in osteochondral repair between FC and PA articular surfaces suggest that the mechanical environment strongly influences the quality of articular surface repair. Decreasing the risk of post-traumatic osteoarthritis following intra-articular fractures will depend on finding methods of promoting the osteochondral repair response including modifying the intra-articular biological and mechanical environments.

Complete median nerve transection as a complication of carpal tunnel release with a carpal tunnel tome

A 48 year-old right-hand-dominant man presented to our institution with paresthesia and loss of feeling along the median nerve distribution of the right hand 1 week after undergoing minimally open carpal tunnel release with the Biomet Indiana Tome at another hospital. At surgery, transection of the median nerve was discovered and repaired. This is the first report of a complete median nerve transection using the revised carpal tunnel tome with a single-pass technique.

Nerve entrapment in athletes

Nerve entrapment syndromes can occur in athletes. The repetitive and vigorous use or overuse of the upper extremity makes the athlete particularly vulnerable to disorders of peripheral nerves. Understanding the clinical signs and symptoms is essential to treatment. The pertinent anatomy, clinical presentation, treatment, and rehabilitation necessary for return to sports for various nerve entrapments have been described. This should enable the physician caring for the athlete to help prevent injury and to guide appropriate treatment, if intervention becomes necessary.

Examination of the anatomic relationship of the proximal germinal nail matrix to the extensor tendon insertion

The purpose of this study was to delineate the relationship of the terminal extensor tendon insertion to the proximal limit of the germinal nail matrix. Sixteen fresh-frozen human cadaver fingers without any evidence of trauma (average age, 55 years; 3 males and 1 female) were used for this study. Under x25 magnification the proximal limit of the germinal nail matrix and the terminal bony insertion of the extensor tendon were identified. The distance from the terminal tendon insertion to the germinal nail matrix was ascertained using precision calipers. The average distance from the terminal extensor tendon insertion to the proximal edge of the germinal nail matrix was found to be 1.2 mm. We conclude that the proximal limit of the germinal matrix is extremely close to the terminal extensor tendon bony insertion. When the extensor tendon insertion is visualized during operative exposures of the dorsum of the distal phalanx, care should be taken to avoid damaging the germinal matrix. Conversely, when the nail bed is being completely excised, visualization of the insertion of the extensor tendon will indicate that further proximal dissection is not required.

Magnetic resonance imaging of injury to the medial collateral ligament of the elbow: a cadaver model

The purposes of this study were to evaluate the usefulness of thin-section 3-dimensional Fourier Transform (3DFT) gradient echo imaging of the medial collateral ligament and to evaluate the usefulness of intraarticular gadolinium for the detection of tears of the ligament. Magnetic resonance imaging was performed on 5 fresh-frozen cadaveric elbows through use of T1-weighted and 3DFT gradient echo T2-weighted sequences. The elbows were then arthroscoped, and lesions were created in the medial collateral ligaments. Magnetic resonance imaging was then repeated with the T1 and 3DFT sequences. In addition, dilute gadolinium was then injected intra-articularly, and fat-suppressed T1-weighted images and 3DFT images were obtained. Magnetic resonance imaging findings were correlated with the appearance of the dissected ligament. We found that in the prearthroscopy specimens, the ligament was best seen on the 3DFT images reformatted into a slightly posteriorly obliqued coronal plane. In the post-arthroscopy elbows, 4 full-thickness perforations were detected with the 3DFT sequence; fat-suppressed T1-weighted images with intraarticular gadolinium detected these 4 as well as 1 partial inner surface tear. In conclusion, fat-suppressed T1-weighted magnetic resonance arthrography with gadolinium can provide information regarding inner surface partial tears and small full-thickness perforations.

Osteoarthritic changes in the biochemical composition of thumb carpometacarpal joint cartilage and correlation with biomechanical properties

The biochemical composition and biomechanical properties of articular cartilage from 53 human thumb carpometacarpal (CMC) joints from cadavers aged 20 to 79 years were measured and studied in normal, mildly fibrillated, and advanced osteoarthritic (OA) joints. Statistical analyses were performed to determine the correlations between the compositional measures and biomechanical properties. For these CMC joint tissues we found that water content increased, proteoglycan content decreased, and collagen content per dry weight remained unaltered with progression of OA degeneration. We also found that with disease progression, as defined by an OA staging score, the aggregate modulus (ie, compressive stiffness) decreased, along with an unexpected moderate decrease in permeability. This latter finding appears to be specific to CMC cartilage degeneration since articular cartilage from knees and hips generally demonstrates an increase in permeability with water content and OA score. Correlations between biochemical composition and biomechanical properties were found to be stronger in joints with OA than in joints without OA. This finding suggests that OA changes in biochemical composition, relative to baseline normal values, directly affect the biomechanical properties of cartilage, even though the baseline compositional values themselves do not directly determine the magnitude of the biomechanical properties in normal tissue.

Management of acute and chronic biceps tendon rupture

In conclusion, the authors believe that younger high-demand patients should be offered the option of surgical repair; can be performed through the preferred single anterior incision with two suture anchors. Chronic tears, even with retraction, may be successfully reconstructed using a free tendon graft, often the flexor carpi radialis. Complications, including radial nerve palsy and proximal radioulnar synostosis, can be avoided with the single-incision technique. Older, low-demand patients can be rehabilitated and have excellent function without acute repair. Partial tendon injuries, for the most part, may be treated with rest and rehabilitation and explored only for chronic, unremitting pain. The authors believe that the single anterior approach should be used over the previously popularized two-incision technique.

Thenar insertion of abductor pollicis longus accessory tendons and thumb carpometacarpal osteoarthritis

Although the etiology of osteoarthritis of the thumb carpometacarpal (CMC) joint remains unclear, some theories have focused on variations in the local anatomy of the abductor pollicis longus tendon insertion. This cadaver study of 68 specimens analyzed the relationship between a thenar insertion of an accessory abductor pollicis longus tendon and the presence and severity of thumb CMC osteoarthritis. The joint cartilage surfaces were visually graded for degenerative changes. Thirty-five of 68 specimens (51%) had a thenar insertion, most frequently inserting on either the abductor pollicis brevis or opponens pollicis fascia or muscle belly. No significant association between a thenar insertion and thumb CMC arthritis was observed. Conversely, increasing age was noted to have a significant association with degenerative joint disease. Thus, these findings indicate that a thenar slip of the abductor pollicis longus tendon does not correlate with the presence or severity of CMC osteoarthritis.

The assessment and treatment of nerve dysfunction after trauma around the elbow

Nerve dysfunction after trauma around the elbow can lead to significant long-term pain and functional deficit. Fortunately, most of these injuries are neurapraxias that will recover spontaneously after conservative treatment. The necessity and time frame for surgical intervention for specific patterns of nerve dysfunction remains controversial. Often surgical exploration exacerbates rather than alleviates the presenting nerve problem. Distal humeral shaft fractures, elbow dislocations, Monteggia fracture-dislocations, supracondylar fractures in children, and proximal forearm trauma all have been associated with various types of nerve injuries with a variable degree of recovery. The early recognition of nerve dysfunction combined with appropriate treatment measures is the key to successful outcome.

Treatment of unstable distal radius fractures with cancellous allograft and external fixation

Unstable fractures of the distal radius continue to pose a challenge to the hand surgeon. Adjunctive bone grafting is often required to augment structural integrity and aid healing. Because of the risks inherent to bone autograft harvest, however, freeze-dried, irradiated cancellous bone allograft has been used to treat unstable distal radius fractures with severe metaphyseal comminution. Seventeen patients with such fractures (mean age, 70 years; 2 males and 15 females) were treated with bone allograft and external fixation with or without internal fixation. The outcome was evaluated using the modified Mayo wrist score, demonstrating 3 excellent, 8 good, 6 fair, and no poor results on follow-up examination (mean follow-up period, 23 months; range, 7-43 months). The patients were requested to return for follow-up review between 1997 and 1998. These results show that cancellous bone allograft is a useful adjunct to external fixation in the treatment of unstable distal radius fractures.

Treatment of a traumatic osteochondral defect in the thumb carpometacarpal joint with a periosteal autograft

We report a case in which an autogenous periosteal autograft was used to resurface a large osteochondral defect in the thumb carpometacarpal joint of a young woman. Good results were found at 4-year follow-up examination.

The teres major muscle: an anatomic study of its use as a tendon transfer

Eleven fresh-frozen cadaver shoulders were dissected to define the anatomy of the teres major muscle and tendon and to determine the muscle's potential for use as a tendon transfer to the humeral head. Of the 11 specimens, 7 had Mathes type II circulation. The primary and secondary pedicles, from the circumflex scapular artery, entered the muscle 4.1 cm and 0.5 cm from the scapula, respectively. The lower subscapular nerve entered 4.1 cm from the scapula. Mean tendon and muscle lengths were 2.0 and 11.8 cm, respectively. As a unipolar transfer, the tendon reached the greater tuberosity in all but 1 specimen. The bipolar transfer offered numerous theoretical possibilities. We believe that the teres major has an appropriate vascular supply and adequate length to make it suitable for tendon transfer to the humeral head.

Lengthening of pediatric forearm deformities using the Ilizarov technique: functional and cosmetic results

Eight patients (average age, 10 years) had a unilateral forearm lengthening procedure using the technique developed by Ilizarov. The procedure was performed in 4 patients with radial agenesis, in 2 with multiple hereditary exostosis, in 1 with ulnar agenesis, and in 1 with multiple enchondromatosis. Patients underwent distraction osteogenesis through either a unifocal or bifocal corticotomy. Forearm length increased on average 6.0 cm (range, 3.6-8.1 cm) or 54% (range, 21% to 94%) with a lengthening index of 1.3 months per centimeter (range, 0.6-1.9 months per centimeter). The length of follow-up averaged 4.5 years and involved office examinations with task evaluation and a questionnaire addressing function and appearance. Limb length discrepancy at follow-up measured 3.7 cm (range, 0.0-8.0 cm). Lengthening of the forearm was found to improve upper extremity function; it allowed the patient to reach distant body parts and to perform select activities requiring near-equal arm length. Forearm lengthening also improved the appearance of the arm if adequate soft tissue was preserved. Full restoration of arm length was not a requirement for a successful outcome and patient satisfaction with the results of the procedure was high.

Chronic elbow instability

Chronic elbow instability without fractures in adults can be broken down into three types: (1) valgus instability, (2) posterolateral rotator instability, and (3) isolated radial head instability. By far the most common is valgus instability, which usually occurs in throwing athletes as a result of repetitive microtrauma to the anterior band of the medial collateral ligament. Surgical treatment is aimed at reconstruction of the anterior band of the medial collateral ligament. Posterolateral rotatory instability is much less common and is diagnosed by the lateral pivot-shift test of the elbow. It is usually the result of an undiagnosed acute injury to the lateral ulnar collateral ligament. Surgical treatment is aimed at its reconstruction. Isolated radial head subluxation in adults is extremely rare. The essential lesion is a disruption of the annular ligament. Surgical treatment is either radial head resection or reconstruction of the annular ligament.

Topography of the osteoarthritic thumb carpometacarpal joint and its variations with regard to gender, age, site, and osteoarthritic stage

The articular topography of 46 osteoarthritic thumb carpometacarpal joints was quantitatively analyzed, as well as variations with regard to gender, age, site, and anatomic osteoarthritic stage. It was found that for osteoarthritic thumb carpometacarpal joints, (1) the opposing articular surfaces of elder and severely degenerated joints are more congruent than those of middle-aged and minimally or moderately degenerated joints, although the articular contact area is not significantly different when accounting for thinning of the cartilage layer with age or disease; (2) significant changes in joint topography due to osteoarthritis only occur in severely degenerated joints; (3) joints in women are less congruent, have smaller contact areas, and are likely to experience higher contact stresses than joints in men for similar activities of daily living that involve similar joint loads; and (4) osteoarthritic changes are less severe on the dorsoulnar aspect of the trapezium and the dorsal aspect of the metacarpal, which are known to be low load-bearing regions.

Knee joint immobilization decreases aggrecan gene expression in the meniscus

Aggrecan is the major proteoglycan of the meniscus, and its primary function is to give the meniscus its viscoelastic compressive properties. The objective of this study was to determine the effect of joint immobilization on aggrecan gene expression in the meniscus. The right hindlimbs of six mature beagles were knee cast-immobilized in 90 degrees of flexion and supported by a sling to prevent weightbearing, while the contralateral limb was left free to bear weight. The animals were sacrificed at 4 weeks, and the anterior and posterior halves of the medial and lateral menisci were analyzed separately. Analysis of aggrecan gene expression by quantitative polymerase chain reaction showed decreased aggrecan gene expression in menisci from immobilized knees (P < 0.01, two-way analysis of variance). Aggrecan gene expression decreased by a factor of 2 to 5.5 in the different regions examined. Analysis of the composition of the meniscus also showed decreased proteoglycan content and increased water content with immobilization (P < 0.05, two-way analysis of variance). These results show that joint immobilization can significantly affect meniscal cellular activity and composition and can therefore potentially affect meniscal function.

Metacarpal shaft fractures: the effect of shortening on the extensor tendon mechanism

Spiral and oblique metacarpal shaft fractures frequently develop shortening through the fracture site. The acceptable amount of fracture shortening has not been well established. The goal of this study was to elucidate the acceptable limits of metacarpal shaft fracture shortening in a cadaver model by assessing the magnitude of the metacarpophalangeal (MCP) joint extensor lag produced. Nine fresh-frozen cadaver hands were used to create a metacarpal shaft fracture model in the second and fifth metacarpal bones. Sequential shortening up to 10 mm in 2-mm increments was performed. The results revealed an average of 7 degrees of extensor lag at the MCP joint produced for every 2 mm of metacarpal shortening. The capacity of the MCP joint for active hyperextension may compensate for the extensor lag produced by metacarpal shortening in the clinical setting.

Repair of rupture of the distal tendon of the biceps brachii. Review of the literature and report of three cases treated with a single anterior incision and suture anchors

Operative repair of distal biceps tendon ruptures is recommended for active individuals desiring maximum return of elbow supination and flexion power and endurance. Traditional two-incision repair methods are highly successful, but they carry the risk of radioulnar synostosis formation if the ulna is exposed. Repair via an anterior incision through bone drill holes requires more dissection and potential risk to the posterior interosseous nerve. The authors present a method of repair of distal biceps tendon ruptures via a single anterior incision using suture anchors. This technique has been used in 3 patients with excellent functional results and is recommended for use as an alternative to the two-incision method.

Surgical exposure of the dorsal proximal third of the radius: how vulnerable is the posterior interosseous nerve?

This study determined the distance between the posterior interosseous nerve and the bicipital tuberosity of the radius in cadavers. Both elbows of 15 preserved cadavers were dissected (eight male cadavers, seven female cadavers). The most prominent point of the radial tuberosity was located, and the shortest distance from this area to the posterior interosseous nerve was measured. The average distance was 2.3 cm (range 1.8 to 3.2 cm); the intracadaver (right vs left) variation was 1.3 mm. The tuberosity to nerve distance was unaffected by forearm rotation. Palpation of the prominence of the radial tuberosity is a reliable guide to the position of the posterior interosseous nerve in dorsal approaches to the proximal forearm.

Contact areas in the thumb carpometacarpal joint

The thumb carpometacarpal joint is a common site of osteoarthritis. It has been hypothesized that peaks of localized stress on the dorsoradial or volar-ulnar regions, or both, of the articular surfaces of the trapezium and metacarpal lead to erosion of cartilage and may be responsible for the progression of the disease. The objective of this study was to determine the contact areas in this joint under the functional position of lateral (key) pinch and in the extremes of range of motion of the joint. These contact areas were assessed relative to the observed sites of cartilage thinning. Eight hands from cadavers of women and five from cadavers of men were tested in vitro with the thumb under a 25 N load in the lateral pinch position, and under small muscle loads (0-5 N) with the thumb in flexion, extension, abduction, adduction, and neutral positions. Contact areas of articular surfaces of the thumb carpometacarpal joint were determined for these positions using a stereophotogrammetric technique. The lateral pinch position produced contact areas predominantly on the central, volar, and volar-ulnar regions of the trapezium and the metacarpal. In three specimens, contact areas were distinctly separated between the dorsoradial and volar-ulnar regions, and in one specimen, from a man, contact occurred exclusively on the dorsoradial region of the trapezium. Using stereophotogrammetry, maps of cartilage thickness also were determined for a subset of nine specimens. The volar-ulnar, ulnar, and dorsoradial regions of the trapezium were the most common sites of thin cartilage, and these may be sites of cartilage wear.(ABSTRACT TRUNCATED AT 250 WORDS)

Long term followup of thorough debridement and cancellous bone grafting of the femoral head for avascular necrosis

From 1977 to 1982, 13 patients were diagnosed with avascular necrosis of the femoral head. The diagnoses were made with a combination of clinical exams, radiographs, tomograms, and Tc99 bone scans. One hip was classified as Ficat Stage I, 9 as Stage II, and 5 as Stage III. There were 11 male and 2 female patients with an average age at the time of surgery of 34 years. Idiopathic osteonecrosis was the final diagnosis in 10 patients, while 3 had a significant history of steroid use. The anterior neck was approached via Watson-Jones or Smith-Petersen approach. A window was then made in the femur at the head/neck junction. Drills, burrs and curettes were utilized under image intensification to perform a thorough debridement of all sclerotic bone. Cancellous bone was harvested from the ipsilateral iliac crest and was packed tightly into the femoral head to the subchondral plate. The cortical window was replaced. In 3 patients a gluteus medius pedicle flap was also utilized to augment the blood supply to the bone graft. This approach provided the access necessary to debride all dead and sclerotic bone. Healing and support of the subchondral plate were subsequently augmented with tightly packed cancellous bone graft. The patients were followed for 10-15 years (mean, 12 years). Two (13%) have since gone on to revision with total hip arthroplasty. The others (87%) remain essentially symptom free with minimal progression of osteoarthritis. There were no infections, femoral neck fractures, or thromboembolic events. Two patients with gluteal pedicle flaps developed ectopic calcification. Thorough debridement and cancellous bone grafting in patients with avascular necrosis of the femoral head is an effective procedure in young patients with Stage II or Stage III disease that will delay, if not prevent, the progression of osteoarthrosis and subsequent total hip arthroplasty.

Mechanical and biochemical changes in the superficial zone of articular cartilage in canine experimental osteoarthritis

The changes in the tensile mechanical properties and biochemical composition of the superficial zone of articular cartilage were examined in a canine model of early osteoarthritis generated by transection of the anterior cruciate ligament. Sixteen weeks following ligament transection, the tensile stiffness of the articular cartilage was decreased by 44% and the ion-induced stress relaxation of the tissue was increased by 57% compared with the contralateral control. Biochemical analyses indicated that the water content of the experimental tissue was increased by 13%, which was reflected as an apparent 37% decrease in the proteoglycan content and a 36% decrease in the collagen content (expressed per wet weight). The hydroxypyridinium crosslink density was decreased in the experimental tissue by 11%. A significant negative correlation was found between the ion-induced stress relaxation and the hydroxypyridinium crosslink density in both control tissue (R = -0.56) and experimental tissue (R = -0.70). No correlation was noted between the tensile stiffness and the biochemical composition of the tissue. These results suggest that, in the superficial zone of articular cartilage, the structure of the tissue may play a more important role than the composition in the determination of its mechanical properties. A major event observed in the model of early osteoarthritis appears to be the disruption and remodeling of the collagen network in the superficial zone of the articular cartilage.

Mechanical and biochemical changes in the superficial zone of articular cartilage in canine experimental osteoarthritis

The changes in the tensile mechanical properties and biochemical composition of the superficial zone of articular cartilage were examined in a canine model of early osteoarthritis generated by transection of the anterior cruciate ligament. Sixteen weeks following ligament transection, the tensile stiffness of the articular cartilage was decreased by 44% and the ion-induced stress relaxation of the tissue was increased by 57% compared with the contralateral control. Biochemical analyses indicated that the water content of the experimental tissue was increased by 13%, which was reflected as an apparent 37% decrease in the proteoglycan content and a 36% decrease in the collagen content (expressed per wet weight). The hydroxypyridinium crosslink density was decreased in the experimental tissue by 11%. A significant negative correlation was found between the ion-induced stress relaxation and the hydroxypyridinium crosslink density in both control tissue (R = -0.56) and experimental tissue (R = -0.70). No correlation was noted between the tensile stiffness and the biochemical composition of the tissue. These results suggest that, in the superficial zone of articular cartilage, the structure of the tissue may play a more important role than the composition in the determination of its mechanical properties. A major event observed in the model of early osteoarthritis appears to be the disruption and remodeling of the collagen network in the superficial zone of the articular cartilage.

Foot drop in a long-distance runner. An unusual presentation of neurofibromatosis

An athletic patient presented with a nontraumatic peroneal neuropathy that failed to resolve after a period of rest. A magnetic resonance image (MRI) showed a multilobulated mass in the course of the common peroneal nerve consistent with a plexiform neurofibroma. Surgical exploration revealed a mass, which coursed from the midthigh to the fibular neck, that was intimately involved with the fibers of the nerve bundle and had cystic degeneration with vesicles along its length. The authors recommend MRI as highly accurate in diagnosing unusual causes of peroneal neuropathy.

Acute dislocation of the carpometacarpal joint of the thumb: an anatomic and cadaver study

An anatomic study was undertaken to provide an understanding of the ligamentous disruption that occurs during acute dislocation of the thumb carpometacarpal joint. Thirty-eight cadaver thumbs were dissected free of soft tissue, with the ligaments preserved. The dorsoradial, posterior oblique, anterior oblique, and intermetacarpal ligaments were identified in all specimens. A dorsal dislocating force was applied to the base of the thumb metacarpal to recreate the mechanism of clinical dislocation. Serial sectioning of the ligaments was performed with the metacarpal in neutral, flexion, and extension. The primary restraint to dorsal dislocation was found to be the dorsoradial ligament, with the anterior oblique ligament allowing dislocation by subperiosteal stripping from the base of the first metacarpal. After reduction, the joint was most stable in pronation and extension, which tightened the anterior oblique ligament. We conclude that the dorsoradial ligament is the primary restraining force with respect to acute dorsal dislocation of the thumb carpometacarpal joint.

In vivo effects of naproxen on composition, proteoglycan metabolism, and matrix metalloproteinase activities in canine articular cartilage

Naproxen is a nonsteroidal anti-inflammatory drug commonly used in the clinical treatment of joint disease. In this study, its effect in vivo on the biochemical composition, metabolic activities, and metalloproteinase activities of normal canine articular cartilage was analyzed. The articular cartilage from the knee joints of dogs who had been given naproxen for 4 weeks to maintain a serum level of 40-50 micrograms/ml was examined. Control animals were given a placebo. Treatment with naproxen was not found to change the composition (water, collagen, and proteoglycan) of the articular cartilage. The culture studies of cartilage explants indicated that proteoglycan synthesis rates were unaffected by the treatment with naproxen but that proteoglycan release from the tissue was suppressed. Analysis of the cartilage for matrix metalloproteinase activities showed reduced activity of neutral matrix metalloproteinase by 80%, of collagenase by 40%, and of gelatinase by 87%, with no change in activity of acid metalloproteinase or of tissue inhibitor for metalloproteinase. These findings indicate that in vivo treatment with naproxen has the capacity to modulate catabolic activities in articular cartilage.

The effect of naproxen and interleukin-1 on proteoglycan catabolism and on neutral metalloproteinase activity in normal articular cartilage in vitro

The events in inflammatory and degenerative joint diseases involve major changes in the metabolic events in the articular cartilage. The effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on articular cartilage metabolism remain unclear, however. The objective of this catabolism of proteoglycans in articular cartilage explants maintained in culture. Release of proteoglycan from the cartilage was compared with release of neutral metalloproteinase activity. The effect of the drug also was determined on the IL-1-stimulated release of proteoglycan and neutral metalloproteinase activity from the explants. At concentrations that included those present in synovial fluids of patients treated with the drug, naproxen sodium was found to suppress the release of proteoglycan and neutral metalloproteinase activity from the articular cartilage extracts. This is in contrast to the well-documented effect of interleukin-1 (IL-1), which was shown to stimulate release of proteoglycan and neutral metalloproteinase activity from articular cartilage. The effect of naproxen sodium on the IL-1-stimulated release was to suppress, but not totally overcome, the increased release of proteoglycan and neutral metalloproteinase activity. In summary, these in vitro studies of cartilage metabolism indicate that naproxen sodium has the potential to suppress catabolic activities in articular cartilage, including those that are motivated by IL-1.

The in vivo effects of naproxen on canine experimental osteoarthritic articular cartilage: composition, metalloproteinase activities and metabolism

A canine experimental model of osteoarthritis (OA), generated by arthroscopic transection of the anterior cruciate ligament (ACL) of the knee, was used to investigate the in vivo effects of the NSAID naproxen on the course of cartilage degeneration. The drug was given at the time of surgery, or from before surgery, and for 16 weeks after surgery. Analysis of the articular cartilage showed the naproxen was able to significantly suppress the decrease in proteoglycan content and metalloproteinase activities. The results indicate that pharmaceutical agents have the potential to modulate the progression of degenerative joint disease.

Curvature characteristics and congruence of the thumb carpometacarpal joint: differences between female and male joints

Three-dimensional geometric models of the articular surfaces of the thumb carpometacarpal (CMC) joint were constructed using precise data obtained from stereophotogrammetry (SPG). It was demonstrated that by using a least-squares surface-fitting technique, the SPG data on the surface can accurately be described by a single parametric biquintic spline function. From this mathematical description, curvature maps of the surfaces were calculated for 13 CMC joints (eight females, average 64 yr old, five males, average 70 yr old). The surface geometry of each joint was analyzed, comparisons were made between trapezial and metacarpal surfaces of the joint and differences determined between males and females. With regard to joint surface areas, the female trapezium is significantly smaller than that of the metacarpal. The shape of the female trapezial surface is also fundamentally different from that of males. No gender-related difference exists regarding the shape of the metacarpal surface. Congruence of the two opposing articular surfaces was defined by their relative principal curvatures. From these definitions, congruence in the radioulnar and dorsovolar anatomic directions, as well as the global congruence of the joint, were calculated. Most CMC joints were found to be more congruent along the radioulnar direction than the dorsovolar direction and, globally, female joints were found to be less congruent than male joints. The concept of joint congruence has played a central role in a number of hypotheses relating to the etiology of CMC joint osteoarthritis (OA), although conflicting hypotheses do exist. The precise quantitative findings of this study may lead to an improved understanding of CMC joint OA, and perhaps explain its prevalence in the female population over 55.

Interspecies comparisons of in situ intrinsic mechanical properties of distal femoral cartilage

We measured the in situ biomechanical properties of knee joint cartilage from five species (bovine, canine, human, monkey, and rabbit) to examine the biomechanical relevance of animal models of human knee joint injuries and osteoarthritis. In situ biphasic creep indentation experiments were performed to simultaneously determine all three intrinsic material coefficients (aggregate modulus, Poisson's ratio, and permeability) of the cartilage as represented by the linear KLM biphasic model. In addition, we also assessed the effects of load bearing on these intrinsic properties at "high" and "low" weight-bearing regions on the distal femur. Our results indicate that significant differences exist in some of these material properties among species and sites. The aggregate modulus of the anterior patellar groove within each species is the lowest among all sites tested, and the permeability of the patellar groove cartilage is the highest and does not vary among species. Similarly, the Poison's ratio in the patellar groove is the lowest in all species, except in the rabbit. These results lead to the conclusion that patellar groove cartilage can undergo greater and faster compression. Thus, under high compressive loads, the cartilage of the patellar groove surface can more rapidly compress to create a congruent patellofemoral joint articulation. For any given location, no differences were found in the aggregate modulus among all the species, and no correlation was found between aggregate modulus and thickness at the test site. Thus, in the process of selecting a suitable experimental animal model of human articular cartilage, it is essential to consider the significant interspecies differences of the mechanical properties.

Experimental studies on repair of large osteochondral defects at a high weight bearing area of the knee joint: a tissue engineering study

There is a vast clinical need for the development of an animal model to study the fundamentals of healing of injured or diseased diarthrodial joints (knee, hip, shoulder, wrist, etc). Current prosthetic replacements do not offer acceptable treatment for injuries and diseases of these joints in young active individuals. New clinical treatment modalities, based on sound biologic principles, are sought for the development of repair or healing tissues engineered to have similar biomechanical properties as normal articular cartilage. In this paper we present a brief review of this need, and propose a grafting procedure which may lead to a successful animal model for studies of long term repair of major osteochondral defects. This grafting procedure uses an autologous periosteum-bone graft or an autologous-synthetic bone replacement graft. We have applied these grafts for in vivo repair of large surgically created defects in the high weight bearing area of the distal femoral condyle of mature New Zealand white rabbits. Further, an interdisciplinary study, including histochemistry, biochemistry (composition and metabolic activities), and biomechanics (biphasic properties), was performed to assess the feasibility of our animal model to generate viable repair tissues. We found our grafting procedure produced, 8 weeks postoperatively, tissues which were very similar to those found in normal articular cartilage. However, our histological studies indicate incomplete bonding between the repair tissue and the adjacent cartilage, and lack of an appropriate superficial zone at the articular surface. These deficiencies may cause long term failure of the repair tissue. Further studies must be undertaken to enhance development of a strong bond and a collagen-rich surface zone. This may require the use of growth factors (e.g., transforming growth factors beta) capable of simulating extra collagen production, or the use of serum derived tissue glue for bonding. At present, we are pursuing these studies.

Arthroplasty of the hand and wrist

The historical perspectives of the wrist and its pathologies are discussed in light of developments made by the pioneers of hand surgery.

Management of severe hand trauma with a mini external fixateur

Maintenance of length, alignment, and mobility while affording ready access for wound care has traditionally been a problem in the management of severe hand trauma. However, miniaturization of existing components of external fixation has provided a significant step in the solution of this problem. Twenty-eight fractures in severely traumatized hands in 24 patients have been managed using a Hoffman mini external fixateur. The patients' mean age was 26.5 years. The dominant hand was involved 60% of the time, and 80% of the population was male. Most fractures (80%) were open injuries with marked comminution, often intra-articular, frequently the result of gunshot wounds (60%). Mini external fixation has afforded proper wound care and maintenance of desired alignment. Complications have been few, while improved results (alignment, range of motion, strength, fracture union), have been demonstrated. Our surgical technique, results, and some illustrative cases are presented.

The use of pulsing electromagnetic fields to achieve arthrodesis of the knee following failed total knee arthroplasty. A preliminary report

Treatment with pulsing electromagnetic fields was used as an adjunct in twenty patients who had had a knee arthrodesis after failure of a total joint arthroplasty. Eighteen had had an infected arthroplasty; one, mechanical loosening; and one, recurrent dislocation. Arthrodesis had been attempted twenty-five times in these twenty patients prior to application of the coils. These procedures included the use of twenty-two external fixation frames, one compression plate, one intramedullary rod, and one cylinder cast. Two groups of patients were identified: those with non-union and those with delayed union. Fourteen patients began treatment six months or more after arthrodesis and were considered to have a non-union. The other six patients started treatment less than six months after attempted arthrodesis because there was no evidence of progression toward union. They were considered to have delayed union. In seventeen (85 per cent) of the twenty patients a clinically solid arthrodesis with roentgenographic evidence of bone-bridging was achieved. The average time to union after coil therapy was started was 5.8 months, with a range of three to twelve months. The patients who started coil treatment earlier after arthrodesis showed a tendency to heal faster. The three patients who had failures were the only ones who did not adhere to the protocol, and all three were in the non-union group. All patients with a solid arthrodesis were free of pain and able to walk at the time of follow-up, nine to thirty-one months after the completion of treatment. The use of pulsing electromagnetic fields appears to be a valuable non-invasive adjunct when performing arthrodesis of the knee after failed total joint arthroplasty.