Metacarpal Base Research Articles

Age dependent T2 changes of bone marrow in pediatric wrist MRI

Hyperintensity of the bone marrow on fluid-sensitive sequences can be seen on magnetic resonance imaging (MRI) during childhood, even in the absence of bone pathology. They can be related to hematopoietic marrow, normal and abnormal bone remodeling. We sought to investigate whether hyper intensity of the bone marrow on MRI of the wrist is age-dependent and to evaluate if this signal follows a consistent age-related pattern. Thirty-one wrist 1.5 T MR images of children (7-18 years) without suspected bone pathology were evaluated for foci of hyperintense bone marrow seen on fluid-sensitive coronal sequences using a scale of 1-3. Correlation of frequency, location and intensity of these foci with age was obtained. Results were analyzed for distribution in single bones and in the following regions: distal forearm, first/second carpal rows, and metacarpal bases. A total of 448 bones were evaluated. Eighty-eight out of 448 (21 out of 31 wrists) showed hyperintense bone marrow seen on fluid-sensitive sequences. The distribution was: radius in 19, ulna in 19, first metacarpal base in 11, scaphoid in 9, lunate in 6, pisiform in 6, and fifth metacarpal base in 1. The involvement of the first and second carpal rows and the metacarpal bases was almost similar (13, 12, and 12 respectively). In the distal forearm, the intensity was similar to or higher than that in the wrist (2.2 vs. 2.0). Frequency decreased with age (100% at 7-9 and 25% at 16-18 years). Foci of hyperintense bone marrow seen on fluid-sensitive sequences can be seen on MRI of the wrist during childhood even without apparent symptoms. It shows a consistent pattern with maturation: frequency and intensity decrease and there is distal-to-proximal resolution. This may be a normal finding that may represent normal bone remodeling or decreasing hematopoietic marrow and should not be confused with pathological bone marrow edema.

Multiple occult wrist bone injuries and joint effusions: prevalence and distribution on MRI

This study aims (1) to assess the prevalence and distribution of multiple occult injuries of the carpal bones and the distal forearm in patients with wrist pain and negative radiographs following trauma and (2) to evaluate the distribution and significance of joint effusions in the wrists with multiple osseous injuries. One hundred and thirty-one subjects, 74 men and 57 women, were consecutively examined in two institutions. All were acute trauma patients with negative X-rays whose clinical examination suggested possible fracture at the wrist or the distal forearm. Magnetic resonance (MR) wrist imaging was performed with and without fat saturation sequences. The MR images were analysed for detection of occult trabecular contusions and cortical discontinuity in the carpus, the distal forearm and the metacarpal bases. The prevalence and distribution of the injuries were assessed along with the distribution of joint effusions. Eight patients were excluded due to inadequate image quality. Two patients had bilateral injury. A total of 125 wrists were analysed. Seventy-eight (62.4%) wrists had occult bone injuries. Among these 78, 53 (68%) wrists had more than one injured bone. Twenty-five wrists (32%) had one injured bone. The highest number of injured bones per wrist was six. Injuries with a visible fracture line were seen in 29 (37.1%) wrists on MRI. The distal radius was the most frequent location for occult fracture line (11 cases). The injuries without a fracture line (contusion) were present in 49 (63%) wrists; they were detected more frequently in the scaphoid (35 cases). The lunate (29 cases) and the triquetrum (26 cases) were almost equally affected. The bone that was less frequently injured was the pisiform (four cases). Joint effusions were present in all 53 wrists with multiple bone lesions but more often situated in the ulnocarpal space [27 (50.3%) wrists]. There was no correlation between effusions in multiple locations (grades III and IV) and multiple bone injuries. This study revealed the presence of multifocal trabecular contusions without correlation with increased joint effusions in patients with negative radiographs and persistent pain. The clinical significance of these findings deserves further investigation.

Thumb Trauma: Bennett Fractures, Rolando Fractures, and Ulnar Collateral Ligament Injuries

Injuries to the thumb are predominated by fractures of the proximal phalanx, ligamentous injuries about the metacarpophalangeal joint, and metacarpal base fractures. This article will attempt to summarize recent advancements within the realm of thumb trauma, with particular attention to Bennett fractures, Rolando fractures, and ulnar collateral ligament injuries.

Skeletal Morphology of a New Genus of Eocene Insectivore (Mammalia, Erinaceomorpha) from Utah

A new genus and 2 new species of erinaceomorph insectivores from the Eocene of Utah are named and described. Both come from Member B of the Uinta Formation, which consists of terrestrially deposited rocks of Early Uintan age. The best specimen consists of dentaries, a few teeth, and several associated elements of the postcranial skeleton; additional dental and postcranial remains also have been recovered. Dentally, the new genus resembles the smaller erinaceomorphs known from earlier in the Rocky Mountain region of North America rather than the contemporary large ones from southern California, indicating that large body size and omnivory evolved independently in different regions of North America during the Eocene. The new genus is primitive in lacking many specializations of the ankle seen in extant erinaceids and other Eocene insectivores. The morphology of the forelimb suggests some digging behavior in having an expanded entepicondyle and the presence of distinct tubercles for insertion of the extensor carpi radialis on the bases of metacarpals II and III. The hind limb exhibits a mosaic of features typical of terrestrial runners, such as anteroposteriorly deep femoral condyles and a deep patellar groove, along with features seen in arboreal climbers, such as a medially and plantarly inflected calcaneal heel. We conclude that the new genus was terrestrial, perhaps moving rapidly over an uneven substrate such as a littered forest floor, but it could probably dig and climb as well.

The Development of EERA: Software for Assessing Rheumatic Joint Erosions

Objective The principal aim of this study was to create a segmentation program, to be used by nonmusculoskeletal or junior fellows, that defines the bones in the metacarpophalangeal joint in a dynamic 3-dimensional image that will lead to higher inter-reader agreement of bone erosion scores. Methods The second to fifth metacarpal head and phalangeal bases of 15 participants were rated according to the Rheumatoid Arthritis Magnetic Resonance Imaging Scoring system by one trained and one untrained reader. Two comparisons were made. The first comparison was between the 2 readers using only the traditional 2-dimensional magnetic resonance image set. The second comparison was between the 2 readers, with the untrained reader using a custom segmentation program with traditional 2-dimensional magnetic resonance image set. Results The software marginally increased inter-reader reliability with the exception of the second metacarpal head, for which reliability was increased substantially. Future work will concentrate on improving image acquisition, better delineate erosions from surrounding bone oedema, and address methods to directly determine erosion volumes. Conclusions Software designed to display dynamic 3-dimensional images enables a relatively untrained user to score the metacarpophalangeal joints in the hand for erosions equivalent to that produced by an expert using the manual methods.

Ligament Reconstruction With Tendon Interposition Using an Acellular Dermal Allograft for Thumb Carpometacarpal Arthritis

Ligament reconstruction tendon interposition arthroplasty is currently the preferred technique for carpometacarpal joint arthritis of the thumb by most surgeons. Despite its efficacy, morbidity has been associated with the harvest of the flexor carpi radialis tendon. Using an allograft as material for arthroplasty, donor site morbidity is avoided. In this report, we present our surgical technique to perform ligament reconstruction tendon interposition arthroplasty using an acellular dermal matrix allograft (GraftJacket) in patients with Eaton stages II, III, and IV symptomatic first carpometacarpal arthritis.One hundred thumbs with trapeziometacarpal osteoarthritis underwent surgical treatment using GraftJacket allograft instead of the flexor carpi radialis tendon autograft. Each patient was followed for a minimum of 12 months. The surgical procedure included trapezial excision and identification of the flexor carpi radialis. The allograft was cut to create a 15-cm strip. The ligament reconstruction was performed by passing the strip around the flexor carpi radialis tendon and suturing it to the base of the thumb metacarpal base through an intramedullary drill hole. The remaining portion of the allograft was fashioned as an interposition mass (anchovy) and interposed between the scaphoid and the base of the first metacarpal.All but 1 patient experienced significant improvement in his or her pain scale rating and grip and pinch strengths. Outcomes from this study compare very favorably with those of other series. No patients experienced a foreign body reaction or infection in this series. We believe that the use of an acellular dermal allograft for both ligament reconstruction and tendon interposition provides a safe and an effective alternative technique for the treatment of advanced first carpometacarpal arthritis.

Management of Rolando Fracture by Modified Dynamic External Fixation

Rolando fracture is one of the most difficult fractures facing hand surgeons. It can be described as a Y- or T-shaped fracture line that runs longitudinally through the metaphyseal area, with an intra-articular fracture splitting the metacarpal base fragment into a volar and a dorsal fragment. In this study, we introduce our technique used in the management of 7 cases, which were treated by our dynamic external fixation. The results were found to be promising, with an excellent range of motion and power grip postoperative. The joints spaces were restored. No patients in our series developed arthritic changes. All patients are pain free in 3 months.

Haematogenous pseudomonas osteomyelitis of the hamate – treatment by radical debridement and bone grafting

A case of isolated chronic osteomyelitis of the hamate bone in a 13-year-old boy, who presented with a sinus on the dorsum of the hand, is reported. Radiological examination revealed multiple marginal and intra-osseous lytic areas with sclerotic rims in the hamate and at the fourth and fifth metacarpal bases. He was treated with excision of the sinus, curettage of the hamate lesion and hamato-metacarpal fusion which provided satisfactory control of infection while salvaging the function of the affected hand.

Stress fracture of the hamate body and fourth metacarpal base following military style push-ups: an unusual trauma mechanism

We report the case of a 19-year-old male soldier, who sustained stress fractures of the hamate body and fourth metacarpal base due to his daily knuckle push-up routine in the military. We introduce repetitive microtrauma due to daily knuckle push-ups as an unusual, but potential trauma mechanism for metacarpal and carpal stress fractures.

Treatment of Avulsion Fractures of the Second Metacarpal Base With a Miniplate and Screws

First-generation porous coated acetabular cups have achieved durable biologic fixation, although liner dissociation and wear were common failure mechanisms. Second-generation modular acetabular cups retained the successful ingrowth surfaces used in earlier cup designs and incorporated congruent contact between the liner and shell. However, impingement-related fractures of highly cross-linked ultra-high-molecular-weight-polyethylene (UHMWPE) used in second-generation cup designs have occurred. Third-generation cup designs that eliminate UHMWPE protruding above the metal rim and minimize sharp corners at the liner-locking mechanism would be expected to reduce the risk of liner fracture in modular acetabular cups used with highly crosslinked UHMWPE.

CLOSED INTRAMEDULLARY FIXATION FOR METACARPAL FRACTURES USING J-SHAPED NAIL

The purpose of this study is to present the results of a new intramedullary fixation technique for metacarpal fractures. A J-shaped nail, which is a curved 2.0 mm diameter Kirschner wire sharply bent at the proximal end, was inserted from the dorsal aspect of the metacarpal base. Twenty-one metacarpal fractures (five transverse shaft fractures and 16 neck fractures) in 19 hands of 18 patients with were operated by this technique. All fractures had successful unions. Clinical and radiographic results were excellent in all ten hands that had excluded concomitant injuries. There was no mechanical irritation of the skin or extensor tendons in any patient. This intramedullary fixation technique is very useful for neck or transverse shaft fractures of the metacarpals without concomitant injuries such as severe soft tissue damage.

A Biomechanical Study of Distal Interphalangeal Joint Subluxation After Mallet Fracture Injury

There is no consensus in the literature regarding the size of a mallet fracture fragment that may lead to subluxation of the distal interphalangeal (DIP) joint. The purpose of this study was to determine the relationship between the size of the dorsal articular fragment and DIP joint subluxation in a cadaveric mallet fracture model. Twenty-nine fresh-frozen fingers without evidence of DIP joint osteophytes were dissected to the metacarpal base. The mean age of the 17 donors at the time of death was 69 years (range, 46 to 89 years). Obliquely oriented fractures through the dorsal lip of the distal phalanx were randomly created with an osteotome (range, 27% to 69% of the joint surface). Each finger was fully flexed and extended 1,200 times by applying alternating tension to the flexor and extensor tendons. Fluoroscopic images were obtained and digitized for measurements of fracture fragment size and DIP joint subluxation. Sixteen DIP joints remained reduced and 13 distal phalanges subluxated palmarward. Subluxation was not observed when the fracture fragment measured less than 43% of the joint surface, whereas subluxation consistently occurred when the defect measured greater than 52% of the articular surface. Subluxation averaged 18% +/- 7% of the overall joint surface in these specimens. There was no correlation between the amount of joint subluxation and the percentage of articular surface damage (p = .22). This study supports the concept that a mallet fracture with a large articular fragment may be unstable. Palmar subluxation of a DIP joint without preexisting arthritic deformity is expected when more than one half of the dorsal articular surface is injured.

Avulsion fracture of the base of the index metacarpal by extensor carpi radialis longus: A Case Report

Avulsion fracture of the base of the second metacarpal is an uncommon injury because of the stability of the carpometacarpal joints. We present a case of fracture of the index metacarpal base with avulsion of the extensor carpi radialis longus tendon. All the previous reports have described fall on flexed wrist as mechanism of injury. This case represents the injury as a result of motor vehicle accident (dashboard injury). It was treated with open reduction and internal fixation using a screw and suture anchor. After surgery, the patient regained full function with normal range of movement and power of the wrist.

The Use of a Dorsal-Distal Portal in Trapeziometacarpal Arthroscopy

An accessory dorsal-distal portal (D-2) was developed to improve the visualization of the medial aspect of the trapezium during an arthroscopic trapeziectomy. This portal is ulnar to the extensor pollicis longus tendon and 1 cm distal to the V-shaped cleft at the juncture of the index and thumb metacarpal bases. The entry site is marked before the tourniquet is elevated to allow palpation or Doppler ultrasound of the radial artery in the anatomic snuffbox. A 22-gauge needle is inserted with proximal, radial, and palmar angulation to penetrate the joint space, which is viewed from either the 1-R or 1-U portal. A small skin incision is made and is followed by the insertion of a blunt trocar and cannula. An anatomic dissection of 5 cadaveric hands revealed that branches of the superficial radial nerve passed within 3.2 mm, the radial artery was 3.8 mm away, the first dorsal metacarpal artery was within 2.8 mm of this portal, and the cephalic vein was within 2.8 mm of this portal. On average, the D-2 portal was 17.2 mm from the 1-U portal (range, 12 to 20 mm). This study provides a safe, standardized approach to the D-2 portal for trapeziometacarpal arthroscopy, which is useful for evaluation of the dorsal capsular ligaments, provides access to medial osteophytes during an arthroscopic partial trapeziectomy, aids in the reduction of intra-articular metacarpal base fractures, and facilitates triangulation of the instruments.

Biomechanic Analysis of Trapeziectomy, Ligament Reconstruction With Tendon Interposition, and Tie-In Trapezium Implant Arthroplasty for Thumb Carpometacarpal Arthritis: A Cadaver Study

Thumb carpometacarpal joint arthritis has been commonly treated with some combination of resection of the trapezium and interposition of a spacer using either a biologic or artificial material plus tenodesis to reconstruct the volar oblique ligament. The purpose of this study was to evaluate the biomechanic stability of the classic ligament reconstruction with tendon interposition (LRTI) or without tendon interposition compared with a newly developed 1-piece silicone trapezium implant. Twelve cadaver arm specimens had the following procedures: resection of the trapezium, tendon interposition, ligament reconstruction, LRTI, and the silicone implant. Biomechanic testing of joint stability was performed with a physiologic loading protocol before and after each procedure. The implant significantly corrected the axial displacement after trapeziectomy and resulted in less radial displacement than LRTI. It significantly reduced angulation of the thumb metacarpal base but resulted in more rotation of the thumb during simulated pinch. There was no significant difference in stability measures between trapeziectomy and LRTI or ligament reconstruction without tendon interposition. We found several biomechanic advantages to the implant compared with LRTI. Advantages include reduction in axial and radial displacement and maintenance of the trapezial space. We attribute these advantages to the effect of the implant as a spacer. The significant rotation with the implant, however, raises questions concerning implant design and fixation. We found no biomechanic advantage to LRTI or ligament reconstruction without tendon interposition over trapeziectomy alone.

Absorbable PDLLA screw for metacarpal fracture fixation

目的 评价国产聚-DL-乳酸(PDLLA)可吸收定位螺钉治疗手部掌骨骨折的临床效果.方法 对36例掌骨干骨折,其中掌骨干骨折19例,掌骨基底部骨折11例,掌骨头骨折6例的患者,采用国产PDLLA可吸收定位螺钉进行内固定治疗.结果 术后伤口均Ⅰ期愈合,随访时间为6～12个月.术后未发生骨折再移位及伤口红肿、渗液等,骨折均获得骨性愈合,愈合时间为6～8周.手功能恢复满意.结论 国产PDLLA可吸收定位螺钉治疗掌骨骨折疗效可靠,值得临床推广使用。

Anatomic variation of the 5th extensor tendon compartment and extensor digiti minimi tendon

Anatomic variation within the 5th extensor compartment may contribute to the development of tenosynovitis and limit the usefulness of the extensor digiti minimi (EDM) for tendon transfer. The purpose of this study was to assess the anatomic variation of the EDM tendon and its surrounding retinaculum, with particular attention to anatomical variation between specimens. Forty-one fresh cadaver hands were dissected. The length of the 5th compartment retinaculum was noted. The incidence of an intercompartmental septum was noted in each specimen as well as the type of tendinous attachments present between the EDM and extensor digitorum communis (EDC) tendons. The presence and length of any accessory retinacular bands distal to the edge of proper extensor retinaculum was also noted. Only one specimen contained a single EDM tendon, while 71% (n = 29) of specimens contained two slips and 23% (n = 9) had three slips; 24% (n = 10) of EDC tendons had no slip to the small finger, while 61% (n = 25) of specimens had a single slip to the small finger. The EDC's contribution to the small finger was found to be an independent tendon in 42% of cases (n = 17), while 34% (n = 14) of specimens were found to have a common EDC slip, which branched to both the ring and small finger. Three EDM tendons divided distal to the extensor retinaculum, while the remaining EDM tendons divided beneath or proximal to the extensor retinaculum. Seventy-three percent (n = 30) of the specimens had an accessory retinacular band surrounding the EDM tendon identified at the base of the 5th metacarpal. Eighty-eight percent (n = 36) of hands had a septum between the EDM slips. The surgeon should be aware of variability within the 5th dorsal compartment in cases of trauma and in cases of tendon transfer. In our series 30 of 41 specimens were noted to contain an accessory dorsal retinacular band surrounding the EDM and 36 specimens were noted to contain a septum within the 5th compartment. The presence of an accessory retinacular band surrounding the EDM at the level of the 5th metacarpal base is an anatomic finding that requires further investigation.

Identification of Two Accessory Muscle Bundles with Anomalous Insertions in the Flexor Side of the Right Forearm

During dissection practice held at Kyorin University School of Medicine in 2004, two anomalous muscles were observed on the Rt-forearm-flexor-side of an 83-year-old man. The results of this investigation are reported. One accessory muscle originated from the tendinous insertion of the biceps brachii and medial epicondyle. After passing through the deep layer of the pronator teres, it became tendinous, passing towards the trapezium and second metacarpal base. Its two origins fused superficial to the ulnar artery distal to the cubital fossa, and it merged with the deep region of the pronator teres. More distally, the accessory muscle formed a belly before again becoming tendinous and bifurcated, one branch attaching to the trapezium and the other fusing with the belly of the second accessory muscle. These findings suggested that this accessory muscle was similar to Gantzer's muscle. The other accessory muscle arose distal to the origin of the flexor pollicis longus and inserted onto the second metacarpal base. In addition, from the distal side of its origin, a small muscle bundle was formed and became tendinous. It fused with the insertion tendon of the first accessory muscle to the trapezium. The second accessory muscle was thought to be deep radial carpal flexor.

The Classic: Fracture of the Base of the First Metacarpal and a Variation That Has Not yet Been Described

The Classic: Fracture of the Base of the First Metacarpal and a Variation That Has Not yet Been Described

Unusual long bone and metacarpo-carpal abnormalities in a case of pseudo-pseudohypoparathyroidism

A case of pseudo-pseudohypoparathyroidism (PPH) with shortening of the left femur and tibia and coalition of the base of the fourth metacarpals with capitatum and hamatum in bilateral wrist joints was presented. Involvement of the fourth digits both in hands and feet were more prominent on the left side, with shortening of the left leg.