Anatomical design and production of a novel three-dimensional co-culture system replicating the human flexor digitorum profundus enthesis.

The enthesis, the specialized junction between tendon and bone, is a common site of injury. Although notoriously difficult to repair, advances in interfacial tissue engineering techniques are being developed for restorative function. Most notably are 3D in vitro co-culture models, built to recreate the complex heterogeneity of the native enthesis. While cell and matrix properties are often considered, there has been little attention given to native enthesis anatomical morphometrics and replicating these to enhance clinical relevance. This study focuses on the flexor digitorum profundus (FDP) tendon enthesis and, by combining anatomical morphometrics with computer-aided design, demonstrates the design and construction of an accurate and scalable model of the FDP enthesis. Bespoke 3D-printed mould inserts were fabricated based on the size, shape and insertion angle of the FDP enthesis. Then, silicone culture moulds were created, enabling the production of bespoke anatomical culture zones for an in vitro FDP enthesis model. The validity of the model has been confirmed using brushite cement scaffolds seeded with osteoblasts (bone) and fibrin hydrogel scaffolds seeded with fibroblasts (tendon) in individual studies with cells from either human or rat origin. This novel approach allows a bespoke anatomical design for enthesis repair and should be applied to future studies in this area.

Return to sport or work following surgical management of scapholunate ligament injury: a systematic review.

INTRODUCTION: This systematic review aims to compare the rate and time to return to sport or work following surgical interventions for isolated scapholunate ligament (SLL) injury. SOURCES OF DATA: A PRISMA-compliant systematic search of Medline, EMBASE, Cochrane, AMED, CINAHL Plus and SPORTDiscus was performed using keywords 'scapholunate', 'scapholunate ligament', 'scaphoid lunate', 'sport', 'sport injury', 'athlete', 'athletic performance', 'elite', 'return to sport', 'training', 'work', 'activity', 'return to activity'. Adult patients with isolated SLL injury, without osteoarthritis, were included. AREAS OF AGREEMENT: Fourteen papers, including six different surgical interventions, met the criteria for the final analysis. All surgical techniques demonstrated acceptable rates of return to work or sport (>80%). AREAS OF CONTROVERSY: The optimal surgical intervention for isolated SLL injury remains undetermined due to heterogeneity and limited sample sizes of published studies. GROWING POINTS: This systematic review has provided clarification on the available literature on treatment modalities for isolated SLL injuries in the absence of osteoarthritis. AREAS TIMELY FOR DEVELOPING RESEARCH: Prospective, randomized, primary studies are needed to establish optimal treatment for acute isolated SLL injuries.

Anatomy and histomorphology of the flexor digitorum profundus enthesis: functional implications for tissue engineering and surgery.

BACKGROUND: The enthesis possesses morphological adaptations across the soft-hard tissue junction which are not fully restored during surgical avulsion repairs. This loss of anatomical structure, highly related to function, contributes to poor clinical outcomes. Investigating the native macro- and micro-structure of a specific enthesis can provide functional and biomechanical insights to develop specialised, novel tissue-engineered therapeutic options and potentially improve current surgical treatments for avulsion injuries. METHODS: This study examines the anatomy and histomorphology of the flexor digitorum profundus (FDP) enthesis in 96 fresh-frozen human cadaveric fingers, quantitatively and qualitatively analyzing the shape, size, angle of tendon fibres and histological architecture, and explores differences in sex, finger and distance along the enthesis using linear mixed effects models. RESULTS: Macroscopically, results showed a consistent trapezoidal insertion shape of 29.29 ± 2.35 mm2 mean surface area, but with significant morphometric size differences influenced primarily by the smaller dimensions of the little finger. Microscopically, a fibrocartilaginous enthesis was apparent with a 30.05 ± 0.72o mean angle of inserting tendon fibres, although regional variation in fibrocartilage and the angle change of tendon fibres before insertion existed. CONCLUSIONS: The implication of these findings on native and specific FDP enthesis function is discussed whilst providing recommendations for optimal FDP enthesis recreation for interfacial tissue engineers and hand surgeons. The study emphasizes the importance of region-specific knowledge whilst also describing methods applicable to assessing any soft tissue insertion.

A Reference Range of Dart-Thrower's Motion at the Wrist in a Healthy Adult Population.

PURPOSE: Dart-thrower's motion (DTM) is a functional wrist movement from maximum radial extension to maximum ulnar flexion. This study defines a reference range of DTM in a healthy population. METHODS: Goniometric measurements were collected from both wrists of 200 healthy volunteers. Mean age was 21.1 years (range, 18-25 years), 126 volunteers (63%) were female, and 177 (89%) were right-handed. Volunteers also reported perceived difficulty of performing DTM. RESULTS: For male subjects, the mean arc of motion was 126° (range, 83°-166°) for dominant and 114° (range, 62°-148°) for nondominant wrists. For female subjects, the mean values were 129° (range, 79°-170°) and 126° (range, 70°-167°), respectively. On multiple regression analysis, female subjects had a significantly increased range of dominant and nondominant arc of motion compared with males. Older subjects had significantly increased dominant but reduced nondominant arc of motion. High inter- and intrarater reliability was observed for goniometric measurement of DTM (intraclass correlation coefficients, 0.93-0.98). CONCLUSIONS: This study quantified a reference range of DTM in normal individuals. CLINICAL RELEVANCE: This study provides a reference range for DTM in a young adult population, which may aid clinical comparison of measurements of wrist movement and evaluation of conditions and treatments that impact DTM.

Establishing local diagnostic reference levels for mini C-arm use in upper limb surgery - A step towards national audit.

AIMS: Under the Ionising Radiation Medical Exposure Regulations, hospitals using fluoroscopy and image intensifiers should monitor doses from exposures using ionising radiation. There is a need for national diagnostic reference levels to advise Orthopaedic and Plastic surgeons on safe screening times and radiation doses for patients having upper limb surgical procedures. METHODS: Retrospective study of all patients who underwent upper limb surgical procedures requiring intra-operative mini C-arm image intensifier use at our hospital between 2013 and 2019. This included results from three machines in different rooms. Procedures were classified as closed and open procedures. RESULTS: Information on a total of 2910 procedures over 6 years (June 2013 to June 2019) were obtained. 133 procedures with incomplete data and 4 cases of lower extremities were excluded. 1719 closed procedures had a median dose area product of 0.48 cGycm2 and median screening time of 7 s, compared to 1054 open procedures, with a median dose area product of 1.88 cGycm2 and median screening time of 28 s. National diagnostic reference levels are set at the third quartile and indicate the difference between good and poor practice. For diagnostic reference levels, we suggest a dose area product of 0.82 cGycm2 and a screening time of 11 s for closed procedures and a dose area product of 3.07 cGycm2 and screening time of 40 s for open procedures. Public Health England state that national diagnostic reference levels should be derived from multiple patients, radiology rooms and hospitals. Our data meets the first two criteria and is an initial step in establishing national diagnostic reference levels for upper limb mini C-arm use. CONCLUSIONS: This large audit reports results, which, with further work across multiple hospital sites, should lead to establishing national diagnostic reference levels for mini C-arm fluoroscopy for upper limb Orthopaedic procedures.

Return to sport following surgical management of triangular fibrocartilage tears: a systematic review.

INTRODUCTION: This review aims to provide information on return rates and times to return to sport following surgical management of triangular fibrocartilage (TFC) tears. SOURCES OF DATA: A systematic search of CINAHAL, Cochrane, EMBASE, Google Scholar, Medline, PEDro, Scopus, SPORTDiscus and Web of Science was performed using the keywords 'triangular', 'fibro-cartilage', 'complex', 'tear', 'distal radio-ulnar joint', 'athletes', 'sports', 'non-operative', 'conservative', 'operative' and 'return to sport'. AREAS OF AGREEMENT: In all of the 10 studies included, conservative management for 6 weeks to 6 months was the first-line treatment. If symptoms persisted following this period, surgical management was advised. Arthroscopic debridement was recommended for central tears, and arthroscopic repair was recommended for peripheral tears. AREAS OF CONTROVERSY: The optimal treatment modalities for TFC tears remain to be defined. GROWING POINTS: Traumatic central tears can be treated with arthroscopic debridement alone. Arthroscopic repair with an all-inside repair can improve return rates to sport over an outside-in technique for ulna-sided tears. AREAS TIMELY FOR DEVELOPING RESEARCH: Future prospective studies should aim to establish the optimal treatment modalities for TFC tears.

Biting the hand that feeds you: Management of human and animal bites.

Bites from animal and humans represent a very small proportion of all the patients presenting to emergency departments, However, they require prompt medical and surgical intervention in order to minimise the risk of infection, that may lead to limb and life-threatening complications. In this review article we synthesise the existing literature for treatment of human and animal bites and offer practical considerations when managing bite injuries.

Ligament reconstruction of the Trapezial-metacarpal joint for early arthritis: a preliminary report.

PURPOSE: To evaluate the results and determine the efficacy of an alternative ligament reconstruction technique in patients with a symptomatic trapezial-metacarpal joint associated with subluxation and early or limited chondral damage. METHODS: This retrospective, nonrandomized study was composed of 6 patients, all women with ages between 31-46 years, treated by arthroscopic evaluation and reconstruction of the intermetacarpal and reverse anterior oblique ligament of the trapezial-metacarpal joint, using a strip of flexor carpi radialis tendon. Evaluation at an average follow-up of 18 months (range,12-28 mo) consisted of interview, examination, and computed tomography. RESULTS: The visual analog pain score, preoperative rest pain, and activity pain improved significantly after surgery. Tip and lateral pinch strength measured 92% compared to the contralateral thumb, and computed tomography showed improved alignment of all joints. CONCLUSIONS: Our results indicate that ligament reconstruction using the technique described reduced pain, increased strength, and improved the trapezial-metacarpal joint alignment in patients with early symptomatic trapezial-metacarpal joint osteoarthritis associated with joint subluxation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Histomorphology of the Subregions of the Scapholunate Interosseous Ligament and Its Enthesis.

Background The scapholunate interosseous ligament (SLIL) has three subregions: dorsal, proximal, and volar. The SLIL enthesis has not previously been studied despite its important mechanical function in wrist joint biomechanics. Questions/Purposes This study aims to compare the histomorphological differences between the SLIL subregions, including at their entheses. Three questions are explored: Do the gross dimensions differ between SLIL subregions? Does the enthesis qualitatively, and its calcified fibrocartilage (CF) quantitatively, differ between (a) SLIL subregions and (b) scaphoid and lunate attachments? Methods Twelve fresh-frozen human cadaveric wrists were dissected and the gross dimensions of the SLIL subregions measured. Subregions were histologically processed for morphological and compositional analyses, including quantification of enthesis CF area. Results The dorsal subregion was the thickest. The dorsal and volar subregions had fibrocartilaginous entheses, while the proximal subregion was attached to articular cartilage. The dorsal subregion had significantly more CF than the volar subregion. There was no significant difference in the enthesis CF between scaphoid and lunate attachments in the three subregions. Conclusions There are significant morphological differences between the SLIL subregions. The dorsal subregion has the largest amount of CF, which is consistent with the greater biomechanical force subjected to this subregion. The similar histomorphology of the ligament at the scaphoid and lunate entheses suggests that similar biomechanical forces are applied to both attachments. Clinical Relevance The histomorphological results confirm that the dorsal subregion is the strongest of the three subregions. The results from the entheseal region may have important implications in the study of graft incorporation during SLIL reconstruction.

The Value of the Distal Radioulnar Joint Effusion in Diagnosing Triangular Fibrocartilage Complex Tears on Magnetic Resonance Imaging.

BACKGROUND: A retrospective study was conducted to evaluate the role of distal radioulnar joint (DRUJ) effusion in aiding the diagnostic accuracy of central triangular fibrocartilage complex (TFCC) tears on non-contrast MRI. METHODS: 89 consecutive patients who had undergone wrist arthroscopy for ulna sided wrist pain in our unit were identified and their preoperative imaging reviewed. Two consultant musculoskeletal Radiologists independently reported the presence or absence of a DRUJ effusion and or a TFCC tear. The inter-observer variability was calculated using weighted Kappa tests. Two by two tables were constructed to calculate the sensitivity and specificity of reported TFCC tear or DRUJ effusion on MRI in correctly diagnosing central TFCC tears identified at arthroscopy. RESULTS: Sensitivity of MRI to report a TFCC tear was 0.56 and specificity was 0.79. Sensitivity increased to 0.89 if either a DRUJ effusion or TFCC tear were seen on MRI. When observed together, the presence of both a DRUJ effusion and a TFCC tear seen on the imaging lead to a sensitivity of 0.74 and PPV of 82% when compared to findings at arthroscopy. In the absence of both DRUJ effusion and TFCC tear, the specificity of MRI increased to 0.92. Agreement by the radiologists on the presence of DRUJ effusion was substantial (k value 0.67) and TFCC tear was moderate (k value 0.58). CONCLUSION: The presence of DRUJ effusion on MRI can further improve sensitivity of MRI in diagnosing central TFCC tears. The sensitivity of detecting a central TFCC tear on MRI scan when both a DRUJ effusion and a TFCC tear were seen (0.74) is comparable to rates demonstrated on MRA meta-analysis results (0.78). Furthermore, considering the absence of both a DRUJ effusion and TFCC tear seen on MRI is useful in excluding the presence of a TFCC tear at arthroscopy.

The effect of surgery for basal osteoarthritis of the thumb on dart thrower's motion.

This study aimed to identify the effects of basal thumb surgery on the range of dart thrower's motion. Thirteen fresh-frozen cadaveric specimens were placed in a customized jig. Simulated scaphotrapeziotrapezoid joint fusion was carried out on all specimens. Half the specimens then underwent trapeziectomy and the rest had excision of the distal pole of the scaphoid. Simulated scaphotrapeziotrapezoid fusion reduced the range of dart thrower's motion to 89% of the range in the intact wrists, from a mean of 117° to 104°. Although this reduction is not large, it was statistically significant. Simulated trapeziectomy caused a very small increase in dart thrower's motion range compared with the range in the intact wrists. Simulated distal pole of scaphoid excision did not change the range of dart thrower's motion. These results may inform preoperative decisions for surgical management of basal osteoarthritis of the thumb.

The Effect of Ring Finger Distal Interphalangeal Joint Stiffness on Grip Strength: A Simulated Study in Normal Participants.

Background: Pain of the hand distal interphalangeal joints may result from trauma, osteoarthritis or inflammatory arthritis. When symptoms are not controlled by non-operative means, surgical arthrodesis may be performed, resulting in complete stiffness of the joint and possible weakening of grip strength. This study aims to quantify the effect of a stiff ring finger distal interphalangeal joint on overall grip strength. Methods: One hundred participants were screened to exclude upper limb pathology. A Jamar dynamometer was used to assess overall hand grip strength. A splint was used to prevent distal interphalangeal joint flexion, thus replicating a fused distal interphalangeal joint. Participants were tested with and without the splint and the results compared. The mean of three grip strength tests was taken. Results: The participants included 55 females. Mean age was 31 (18-60 years). 76 participants had a reduction in grip strength with splinting, with a significant difference seen (p < 0.05) on Wilcoxon signed rank test. The median reduction in grip strength with splinting was 1.67 kg. However only 10 participants (10%) had a grip strength loss of greater than 6.5 kg, which is the minimal clinically important difference. Conclusions: This study found a significant loss in overall hand grip strength when the ring finger distal interphalangeal joint was stiffened. However, despite this significant change, only 10 (10%) participants experienced a reduction of greater than 6.5 kg. This is the level of weakness felt to be required to reduce function. Thus our results suggest that 90% of patients with a stiff ring finger distal interphalangeal joint are unlikely to have a clinically identifiable functional reduction in grip strength as a result.

Radiation exposure of patients during mini C-arm use: an audit in 2032 procedures.

This study aimed to audit large quantities of mini C-arm data used in hand and wrist surgery and to analyse what effect the type and anatomical location of procedures had on screening time and dose area product. Of a total of 2032 procedures, the median screening time was 11 seconds and median dose area product was 0.75 cGycm2. The third quartile value for screening time was 23 seconds and dose area product was 1.62 cGycm2. The median screening time for closed procedures was 7 seconds and the dose area product was 0.57 cGycm2. The median screening time for open surgery was 23 seconds with a median dose area product of 1.45 cGycm2. The data for steroid injection procedures were similar to those of the closed procedures, with a median screening time of 7 seconds and dose area product of 0.45 cGycm2. We found no significant differences in the screening time or dose area product between procedures on the wrist and forearm compared with the hand and digits. Level of evidence: III.

A comparison of dart thrower's range of motion following radioscapholunate fusion, four-corner fusion and proximal row carpectomy.

Dart thrower's motion is the functional coupled movement of the wrist from radial extension to ulnar flexion. The aim of this study was to evaluate dart thrower's motion following three surgeries: radioscapholunate fusion, four-corner fusion and proximal row carpectomy. Six fresh-frozen cadaver forearms were dissected. Sequential loading of tendons resulted in radial extension and ulnar flexion allowing dart thrower's motion measurements at end range before and then again after each surgery. After radioscapholunate fusion, 74% of both radial extension and ulnar flexion were maintained. After four-corner fusion, radial extension decreased to 53% and ulnar flexion to 84% of control motion. Proximal row carpectomy did not statistically significantly alter radial extension, but decreased ulnar flexion to 87%. We found that dart thrower's motion is well maintained in three of these commonly used surgical treatments. These results may aid surgeons in managing patients by providing comparative functional movement following these procedures.

The Stabilising Effect of the Anterior Oblique Ligament to Prevent Directional Subluxation at the Trapeziometacarpal Joint of the Thumb: A Biomechanical Cadaveric Study.

BACKGROUND: The trapeziometacarpal joint (TMCJ) is inherently unstable, relying on ligament restraint to prevent subluxation. Subluxation of the thumb in a dorsoradial direction is often observed in clinical practice, either after acute ligament injury or more commonly with osteoarthritis (OA). This subluxation follows loss of function of trapeziometacarpal ligaments that stabilise this joint, resisting the deforming force of abductor pollicis longus (APL). The exact ligaments that stabilise and prevent the thumb from the pull of APL causing dorsoradial subluxation remain unknown, although the anterior oblique ligament (AOL) has been implicated. The aim of this study was to measure the direction of subluxation resisted by the AOL. METHODS: In this study we used cadaveric limbs and custom made biomechanical testing to measure the influence AOL has in stabilising the thumb against subluxation in three planes: radial, dorsal and dorsoradial. Three fresh frozen hands were dissected to expose the TMCJ, leaving all ligaments, capsule and APL attachment in place. The force required to create a displacement of 5mm between the first metacarpal and the trapezium in these three planes was measured before and after AOL division. RESULTS: The average force to displace in the dorsoradial plane prior to division was 6.68N, and a statistically significant reduction to 1.15N (P<0.001) was found after division of the AOL. A statistically significant increase in force (P<0.001) from 2.89N to 4.04N was seen in the radial plane, while no change was seen dorsally (P=0.98), with average forces of 2.74N and 2.62N found pre and post division. CONCLUSION: There is clinical significance in reporting quantifiable data in this field, as subluxation of the thumb is often seen with OA. The results of our study provide support for surgical reconstruction of the AOL as the primary surgical stabilizer against dorsoradial subluxation of the thumb.Level of evidence: III.

Characterisation of cryopreserved cells freshly isolated from human bone marrow.

Osteoblast progenitor cells (OBPCs) isolated from bone marrow have the ability to differentiate into osteoblasts and thus potential therapeutic use to tissue-engineer bone. In order for OBPCs to be available for clinical use a means of storing viable cells is necessary. The aim of this study was to determine whether a simple method of cryopreservation had an effect on osteogenic differentiation or growth of OBPCs isolated from fresh human bone marrow. Stro-1 was used to identify the isolated OBPCs. The osteoblastic potential of the marrow cells was confirmed as culture with osteogenic supplements (OS) significantly increased osteoblastic protein production (alkaline phosphatase (ALP), osteopontin and osteocalcin) compared with standard conditions (P less than 0.05). Ten further marrow aspirates were harvested; each was halved for either cryopreservation or control culture. Primary cultures from both populations formed colonies with recognised OBPC morphology. OS stimulated both cryopreserved and control populations to produce significantly more osteoblastic proteins (P less than 0.05) and there was no significant difference between the increase in osteogenic proteins when cultured with OS (P great than 0.2). The proliferation rate after 5 days in culture was not significantly affected by cryopreservation (P greater than 0.05). It has been suggested that OBPCs are immuno-privileged; so allogenic cells could be implanted into patients for tissue engineering bone without causing a hypersensitivity reaction. Our study demonstrates a method of storage, which allows OBPCs to be available for use without affecting osteoblastic potential or viability.