A quantitative analysis of two cementing techniques in total elbow replacement: A cadaveric study.

One of the reasons for failure of total elbow replacement is loosening of the ulnar component. Cementing techniques are often outdated. A special small nozzle is needed for the ulnar component, when a cement gun is used. This may not always be available, or surgeons may prefer to use a syringe. We postulated that the use of a cement gun and smaller nozzle would result in improved filling of the ulnar canal. A cadaveric study was performed in which the ulnas of paired specimens were cemented with a cement gun or with a syringe. A 3D printed ulnar component was inserted and computed tomography scanning was performed on all specimens. Filling of the ulnar intramedullary canal was analysed using 3D reconstructions of the specimens. A greater degree of filling was seen by the use of the cement gun in 85.7%. Filling was 52.7% in the syringe group (25.1-78.7%), compared to 63.3% for the cement gun group (p < 0.05). The use of a small nozzle cement gun provided a significantly higher filling degree of the ulnar canal. We recommend to always use a cement gun with a specific small nozzle to cement the ulnar component in total elbow arthroplasty.

Primary endoprosthetic replacement of the arthritic CMC-1 joint.

OBJECTIVE: Osteoarthritis of the carpometacarpal (CMC)-1 joint is a common condition that can cause significant pain and functional problems. When nonoperative management fails, surgery may be indicated. Resection of the trapezium, often combined with soft tissue stabilization, is still considered the gold standard. But recovery time is often prolonged and a significant number of patients remain unsatisfied in the long term. Knowing that total endoprosthetic joint replacement is one of the most successful achievements of orthopedic surgery, many attempts have been made to produce a replacement for the CMC­1 joint that provides a better outcome than trapeziectomy. INDICATIONS: Eaton-Glickel stage 2-3 CMC­1 osteoarthritis. CONTRAINDICATIONS: Symptomatic pan-trapezial osteoarthritis (Eaton-Glickel stage 4), infection, young manual worker, poor bone quality or insufficient trapezium size. SURGICAL TECHNIQUE: A dorsoradial approach to the CMC­1 joint is used. Minimal resection of the trapezial and metacarpal articular surfaces, including osteophytes and loose bodies. Reaming of the trapezium and broaching of the metacarpal stem with dedicated instruments. Implantation of the endoprosthetic components. Selection of the correct neck length to ensure a stable joint. Closure of the capsule and skin. POSTOPERATIVE MANAGEMENT: Immobilization of thumb for 2 weeks in a splint. Followed by a removable thumb CMC brace for 4 weeks, starting with gentle mobilization exercises. No forceful gripping or pinching the first 6 weeks. RESULTS: A specific design-the uncemented, ball in socket, metal on polyethylene total joint replacement-has stood the test of time and successful long-term clinical and radiographic outcome results have been published. Recent comparative trials have shown better pinch strength, better pain relief and faster functional recovery, when compared to trapeziectomy with ligament reconstruction and tendon interposition. The incidence of complications such as dislocation, polyethylene wear and cup loosening is acceptable.

Four-corner fusion versus proximal row carpectomy : a retrospective review with a minimal follow-up of 9 years.

A retrospective survey on the long-term outcomes of both proximal row carpectomy (PRC) and scaphoidectomy with 4-corner arthrodesis (4CA) was conducted. Seventeen PRC and nine 4CA wrists were retrieved with a minimal follow-up of 9 years. Pain, satisfaction and disability were not significantly different. There was a better flexion and ulnar deviation in the PRC wrists. Conclusion : at long term, the outcome for PRC remains stable despite some series recently reported worsening of the results due to progressive degenerative arthritis. PRC seems to yield comparable clinical results compared to 4CA but a slightly better range of motion than 4CA.

Use of three-dimensional technology for complications of upper limb fracture treatment.

In malunion cases, restoration of anatomy is a key factor in obtaining a good functional outcome, but this can be technically very challenging.Three-dimensional printed bone models can further improve understanding of the malunion pattern.The use of three-dimensional (3D) computer planning, and the assembly of patient-specific instruments and implants, especially in complex deformities of the upper limb, allow accurate correction while reducing operation time, blood loss volume and radiation exposure during surgery.One of the major disadvantages of the 3D technique is the additional cost because it requires specific computer software, a dedicated clinical engineer, and a 3D printer.Further technical developments and clinical investigations are necessary to better define the added value and cost/benefit relationship of 3D in the treatment of complex fractures, non-unions, and malunions. Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180074.

Validation of a Simple Overlay Device to Assess Radial Head Implant Length.

PURPOSE: A simple overlay device (SOD) was developed to measure radial head implant length. The purpose of this study was to determine the accuracy and reliability of this device for measuring experimental radial head implant length. METHODS: Five fresh frozen cadavers were implanted with sequentially longer implants, adjusted by neck length (0, 2, 4, and 8 mm). Fluoroscopic images were obtained in 4 forearm positions: anteroposterior in supination in full extension, anteroposterior in pronation in full extension, supinated in 45° of flexion, and neutral in 45° of flexion. The SOD measurements (made by 2 observers) were compared with the native original radial head (control) to assess implant length. In addition, gapping of the ulnohumeral joint space was measured for comparison purposes. RESULTS: The measured radial head and neck lengths for the specimens were 33, 39, 31, 34, and 42 mm. The difference between the actual radial head and neck lengths and those measured with the SOD template averaged less than 2 mm for all 4 collar sizes, except in 1 measurement in which the bicipital tuberosity could not be visualized. The median intraclass correlation coefficients for observer 1 compared with the SOD were 0.94 to 0.99. The median intraclass correlation coefficients between observers were 0.88 to 0.95. For both observers, elbow position, collar height, and the 2 variables combined did not significantly affect the SOD values. The other method that was evaluated, that of measurement of the ulnohumeral joint space, had higher interobserver variability versus the SOD, and allowed detection of lengthening of over 4 mm. CONCLUSIONS: The SOD is a reliable method for simply assessing radial head length with radiographs and can accurately detect 2 mm or more of proximal radial lengthening. CLINICAL RELEVANCE: The SOD is a simple and accurate method that can help to optimize radial head sizing.

Corrective osteotomy of distal radius malunions using three-dimensional computer simulation and patient-specific guides to achieve anatomic reduction.

Malunion is a common complication of distal radius fractures, especially those treated conservatively. In clinical studies, a significant correlation between anatomic reduction and wrist function has been shown. Corrective osteotomy is the preferred treatment for symptomatic cases, notwithstanding the technical challenges. The use of computer simulation improves pre-operative understanding of the three-dimensional deformity. Patient-specific surgical guides, based on precise pre-operative planning, lead to superior perioperative accuracy and reproducibility. The pre-operative planning and surgical technique of distal radius corrective surgery using three-dimensional computer technology are described in detail. The preliminary results demonstrate the excellent clinical and radiographic outcome of this technique.

Anthropometric Study of the Radiocapitellar Joint.

PURPOSE: There is scant knowledge about the relationship between the size of the radial head and the size of the capitellum. Also, no data exist comparing the size of the capitellum between the left and the right elbow. METHODS: Eight pairs of elbows and 12 single elbows from fresh-frozen cadavers were obtained for this study. The vertical height and anterior width of the capitellum were measured with digital calipers. Four different measurements were performed at the radial head: longest outer diameter, shortest outer diameter, the long dish diameter, and short dish diameter. The Pearson intrarater intraclass correlation coefficients were obtained for all measurements. RESULTS: For the paired elbows, the correlations ranged between 0.95 and 0.96 for the capitellar dimensions and 0.77 and 0.98 for the radial head dimensions. The correlations between the long outer diameter of the radial head with the vertical height and the anterior width of the capitellum were 0.8 and 0.9, respectively. CONCLUSIONS: There is a high correlation between the long outer diameter of the radial head and the vertical height of the capitellum as well its anterior width. There is also a high correlation between the left and the right elbow. CLINICAL RELEVANCE: These findings are relevant to radiocapitellar arthroplasty and may be useful for radiocapitellar prosthetic design as well as in the preoperative planning of cases in which the radial head and/or the capitellum is destroyed.

Percutaneous, Transtrapezial Fixation without Bone Graft Leads to Consolidation in Selected Cases of Delayed Union of the Scaphoid Waist.

Purpose We evaluated clinical and radiographic outcome of percutaneous transtrapezial fixation of the scaphoid delayed union or nonunion using a headless bone screw without bone grafting. Methods Sixteen patients with delayed union or nonunion of the scaphoid were included in this retrospective study between 2006 and 2011. All patients had a delayed presentation of scaphoid fracture, and none of them was treated conservatively elsewhere. Patients with bone graft, sclerotic bone debridement, or displacement of the fragment at the nonunion site were excluded. A percutaneous transtrapezial fixation technique was used in all cases. Patients were reviewed until clinical and radiographic union was observed. At the final follow-up, DASH (Disabilities of the Arm, Shoulder and Hand) and PRWHE (Patient-Rated Wrist and Hand Evaluation) outcome scores were completed. Results Radiographic union was obtained in 15 out of 16 patients (94%) at an average follow-up of 36 months (range: 12-98 months). No complications from the percutaneous technique were noted. The average DASH score was 6 (range: 0-39) and the average PRWHE score was 10 (range: 0-56). No statistical significant difference in range of motion and grip strength was found between the operated side and the contralateral side. Conclusion Percutaneous transtrapezial screw fixation for delayed or nonunion of selected scaphoid fractures without bone grafting is promising. At a mean of 4 months, 94% union was obtained with good functional results when there was no sclerosis, minimal osteolysis, and no displacement at the scaphoid nonunion site. Type of Study Therapeutic study. Level of Evidence IV.

Biomechanical considerations in the pathogenesis of osteoarthritis of the elbow.

Osteoarthritis is the most common joint disease and a major cause of disability. Distinct biological processes are considered crucial for the development of osteoarthritis and are assumed to act in concert with additional risk factors to induce expression of the disease. In the classical weightbearing joints, one such risk factor is an unfavourable biomechanical environment about the joint. While the elbow has long been considered a non-weightbearing joint, it is now assumed that the tissues of the upper extremity may be stressed to similar levels as those of the lower limb, and that forces across the elbow are in fact very high when the joint is extended from a flexed position. This review examined the available basic science, preclinical and clinical evidence regarding the role of several unfavourable biomechanical conditions about the elbow on the development of osteoarthritis: post-traumatic changes, osteochondritis dissecans, instability or laxity and malalignment. Post-traumatic osteoarthritis following fractures is well recognized, however, the role of overload or repetitive microtrauma as risk factors for post-traumatic osteoarthritis is unclear. The natural course of untreated cartilage defects in general, and osteochondritis dissecans at the elbow in particular, remains incompletely understood to date. However, larger lesions and older age seem to be associated with more symptoms and radiographic changes in the long term. Instability seems to play a role, although the association between instability and osteoarthritis is not yet clearly defined. No data are available on the association of malalignment and osteoarthritis, but based on force estimations across the elbow joint, it seems reasonable to assume an association.

Lateral Tibial Posterior Slope Is Increased in Patients With Early Graft Failure After Anterior Cruciate Ligament Reconstruction.

BACKGROUND: The lateral tibial posterior slope (LTPS) has been reported in multiple studies to correlate with an increased risk for native anterior cruciate ligament (ACL) tearing. To date, no study has examined the effect of an increased LTPS as measured on magnetic resonance imaging (MRI) on the likelihood of ACL graft failure. HYPOTHESIS: An increased LTPS as measured on MRI would correlate with an increased risk for ACL graft failure. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Fifty-eight patients were initially identified who experienced graft failure after primary ACL reconstruction and underwent revision between 1998 and 2009. Exclusion criteria were clinical follow-up of less than 4 years, graft failure occurring greater than 2 years after primary surgery, skeletal immaturity, deep infection, lack of available preoperative MRI, and history of trauma to the proximal tibia. This left 35 patients with early (within 2 years) failure of primary ACL reconstruction. These patients were matched to 35 control participants who had undergone ACL reconstruction with a minimum of 4 years of clinical follow-up and no evidence of graft failure. Patients were matched by age, sex, date of primary surgery, and graft type. The LTPS was then determined on MRI in a blinded fashion. RESULTS: The mean time to failure in patients in the study group was 1 year (range, 0.6-1.4 years). The mean follow-up of those in the matched control group was 6.9 years (range, 4.0-13.9 years). The mean LTPS in the early ACL failure group was found to be 8.4°, which was significantly larger than that in the control group at 6.5° (P = .012). The odds ratio for graft failure considering a 2° increase in the LTPS was 1.6 (95% CI, 1.1-2.2) and continued to increase to 2.4 (95% CI, 1.2-5.0) and 3.8 (95% CI, 1.3-11.3) with 4° and 6° increases in the LTPS, respectively. No significant association was identified between graft type and graft failure. CONCLUSION: An increased LTPS is associated with an increased risk for early ACL graft failure, regardless of graft type. Orthopaedic surgeons should consider measuring the LTPS as part of the preoperative assessment of ACL-injured patients.

What does the transverse carpal ligament contribute to carpal stability?

Background The transverse carpal ligament is well known for its involvement in carpal tunnel syndrome, and sectioning of this ligament remains the definite treatment for this pathology. Some authors believe that the transverse carpal ligament is an important stabilizer of the carpal arch, whereas others do not consider it to be significant. Several studies have been performed, both in vivo and in in vitro. Sectioning of the transverse carpal ligament does not seem to have any effect on the width of the carpal arch in the unloaded condition. However, patients will load the arch during their activities of daily living. Materials and Methods A cadaveric study was done with distraction of the carpal bones before and after sectioning the transverse carpal ligament. Results With the transverse carpal ligament intact, the carpal arch is mobile, with distraction leading up to 50% widening of the arch. Sectioning of the transverse carpal ligament resulted in a significant widening of the carpal arch by a further 30%. Conclusions Loading of the carpal arch after sectioning of the transeverse carapal ligament leads to a significant increase in intracarpal mobility. This will inevitably influence carpal kinematics in the patient and might be responsible for some complications after simple carpal tunnel releases, such as pillar pain, palmar tenderness, and loss of grip strength.

Computer navigation and patient-specific instrumentation in shoulder arthroplasty.

Longevity of total anatomic and reversed shoulder arthroplasty largely depends on accurate correction of glenoid deformity and correct positioning and fixation of the glenoid component. However, the morphology of the scapula is inconsistent, varying degrees of osteoarthritis cause numerous anatomic changes, and standard 2-dimensional imaging and standard surgical instrumentation are imprecise for preoperative planning and execution of glenoid reconstruction. Recently, various authors have shown that preoperative 3-dimensional surgical planning and computer navigation technology may increase the accuracy and repeatability of the implantation of the glenoid component, especially for the position and orientation of the glenosphere and screws in reversed arthroplasty. These novel techniques may allow the surgeon to better define the preoperative deformity, select the optimal implant position, and then accurately execute the plan at the time of surgery. Future studies are needed to determine the long-term effect on functional outcome and cost-effectiveness of computer-assisted technology in shoulder arthroplasty.

Transforming growth factor-ß (TGF-ß) expression is increased in the subsynovial connective tissue in a rabbit model of carpal tunnel syndrome.

Carpal tunnel syndrome (CTS) is an idiopathic disease that results from increased fibrosis of the subsynovial connective tissue (SSCT). A recent study found overexpression of both transforming growth factor-ß (TGF-ß) and connective tissue growth factor (CTGF) in the SSCT of CTS patients. This study investigated TGF-ß and CTGF expression in a rabbit model of CTS, in which SSCT fibrosis is induced by a surgical injury. Levels of TGF-ß1 and CTGF at 6, 12, 24 weeks after injury were determined by immunohistochemistry A significant increase in TGF-ß1 and a concomitant significant increase in CTGF were found at 6 weeks, in addition to higher cell density compared to normal (all p<0.05), Interestingly, CTGF expression was reduced at 12 and 24 weeks, suggesting that an initial insult results in a time limited response. We conclude that this rabbit model mimics the fibrosis found in human CTS, and may be useful to study pathogenetic mechanisms of CTS in vivo.

The effect of low- and high-velocity tendon excursion on the mechanical properties of human cadaver subsynovial connective tissue.

Fibrosis of the subsynovial connective tissue (SSCT) in the carpal tunnel is the most common histological finding in carpal tunnel syndrome (CTS). Fibrosis may result from damaged SSCT. Previous studies found that with low-velocity (2 mm/s), tendon excursions can irreversibly damage the SSCT. We investigated the effect of tendon excursion velocity in the generation of SSCT damage. Nine human cadaver wrists were used. Three repeated cycles of ramp-stretch testing were performed simulating 40%, 60%, 90%, and 120% of the middle finger flexor tendon superficialis physiological excursion with an excursion velocity of 60 mm/s. Energy and force were calculated and normalized by values obtained in the first cycle for each excursion level. Data were compared with low-velocity excursion data. For high-velocity excursions, a significant drop in the excursion energy ratio was first observed at an excursion level of 60% physiological excursion (p < 0.024) and that for low-velocity excursions was first observed at 90% physiological excursion (p < 0.038). Furthermore, the energy ratio was lower at 60% for high velocities (p ≤ 0.039). Increasing velocity lowers the SSCT damage threshold. This finding may be relevant for understanding the pathogenesis of SSCT fibrosis, such as that accompanying CTS, and a relationship with occupational factors.

The effect of suture preloading on the force to failure and gap formation after flexor tendon repair.

PURPOSE: Gap formation is a common and severe complication after flexor tendon repair that can affect the outcome and prolong tendon healing. The purpose of this study was to investigate the effect that a pretensional force applied to the suture during tendon repair has on the repair strength and force that causes gap formation. METHODS: We used a total of 48 flexor digitorum profundus tendons from 12 human cadaver hands. We employed a core tendon suture, using the modified Pennington technique, and a running suture for flexor tendon repair. Before tying the knots of the core suture, we preloaded the sutures in each tendon end 0, 5, 10, or 15 N for 10 seconds to compare the effect of loading magnitude on repaired tendon peak force to failure and force causing gap formation. RESULTS: The force to form a gap of 2 mm in the 15-N preload group was significantly increased compared with the 0-N and 5-N preload groups. At the 3-mm gap formation, the force of all preload groups was significantly higher than the nonpreload group. The peak force with a preload of 10 N and 15 N was significantly higher than 0-N preload. CONCLUSIONS: These findings suggest that pretensioning with 10 to 15 N at the suture-tendon interface before tying the knot has a beneficial effect on both the tendon gap formation and the peak force to failure. CLINICAL RELEVANCE: When the surgeons perform tendon repair, pretensioning at the suture-tendon conjunction will increase the repair strength.

The effect of time after shear injury on the subsynovial connective tissue and median nerve within the rabbit carpal tunnel.

BACKGROUND: The most prominent nonneurological finding in the common compression neuropathy carpal tunnel syndrome (CTS) is fibrosis of the subsynovial connective tissue (SSCT). Recently, a rabbit model of CTS has been developed, based on the hypothesis that SSCT injury and subsequent fibrosis cause nerve compression. The purpose of this study was to evaluate the effects in this model at earlier and later time points than have heretofore been reported. METHODS: Sixty rabbits were operated on and observed at two different time periods: 6 and 24 weeks. Nerve electrophysiology (EP), SSCT histology, and SSCT mechanical properties were assessed. RESULTS: There was no significant difference in median motor nerve amplitude or latency at either time point. The total cell density in the SSCT was significantly higher at 6 and 24 weeks compared to controls. The mean size of the collagen fibrils in the SSCT was higher 6 and 24 weeks after surgery compared to controls. Both the ultimate load and the total energy absorption of the SSCT were significantly higher at 6 and 24 weeks compared to controls. CONCLUSIONS: In this model, there were signs of SSCT fibrosis and histology changes at 6 weeks, which persist after 24 weeks. Thus, this model leads to sustained SSCT fibrosis, which is one characteristic of human CTS. However, no significant EP changes were found at these two time points, which is in contrast to the findings reported previously for this model at 12 weeks. The significance of the differences in EP findings will be the subject of future studies.