Purpose: The role of the posterior bundle of the medial collateral ligament (PMCL) in stability of the elbow remains poorly defined. The purpose of this study was to determine the effect of sectioning the PMCL on the stability of the elbow. Method: Varus and valgus gravity-loaded passive elbow motion and simulated active vertical elbow motion were performed on 11 cadaveric arms. An in-vitro elbow motion simulator, utilizing computer-controlled pneumatic actuators and servo-motors sutured to tendons, was used to simulate active elbow flexion. Varus/valgus angle and internal/external rotation of the ulna with respect to the humerus were recorded using an electromagnetic tracking system. Testing was performed on the intact elbow and following sectioning of the PMCL. Results: With active flexion in the vertical position the varus/valgus kinematics were unchanged after PMCL sectioning (p=0.08). However, with the forearm in pronation, there was a significant increase in internal rotation after PMCL sectioning compared to the intact elbow (p< 0.05) which was most evident at 0° and 120° degrees of flexion (p< 0.05). This rotational difference was not statistically significant with the forearm in supination (p=0.07). During supinated passive flexion in the varus position, PMCL sectioning resulted in increased varus angulation at all flexion angles (p< 0.05). In pronation varus angulation was only increased at 120° of flexion (p< 0.05). However, internal rotation was increased at flexion angles of 30° to 120° (p< 0.05). In supination, sectioning the PMCL had no significant effect on maximum varus-valgus laxity or maximum internal rotation (p=0.1). However, in pronation, the maximum varus-valgus laxity increased by 3.5° (30%) and maximum internal rotation increased by 1.0° (29%) (p< 0.05). Conclusion: These results indicate that isolated sectioning of the PMCL causes a small increase in varus angulation and internal rotation during both passive varus and active vertical flexion. This study suggests that isolated sectioning of the PMCL may not be completely benign and may contribute to varus and rotation instability of the elbow. In patients with insufficiency of the PMCL appropriate rehabilitation protocols (avoiding forearm pronation and shoulder abduction) should be followed when other injuries permit

The kinematic effect of tunnel orientation and position, during ACL reconstruction, has been only recently related to the control of rotational instability. This paper presents a detailed computer-assisted in vitro evaluation of two different femoral tunnel orientations with the same tunnel position, at 10.30 ‘o clock, during the intervention of ACL reconstruction with double bundle technique. Results highlighted better kinematic performances of the horizontal tunnel, with respect to the vertical one, in controlling antero-posterior (AP) laxities at 30°, and internal-external (IE) laxities. Elongations of anterior and posterior bundles of reconstructed ACL, for both reconstruction, decreased during PROM respectively by 20% and 40%. Total length of the graft varied during PROM, mainly due to graft elongation during tests, graft length on horizontal tunnel varied from 237 to 213mm while graft length on vertical tunnel varied from 257 to 233mm. Kinematic tests showed a better performance of horizontal tunnel in the control of IE rotations at 30° and 90° and of the Lachman test with respect to the vertical one. Stability was restored with both reconstructions

The causes of a stiff elbow are numerous including: post-traumatic elbow, burns, head injury, osteoarthritis, inflammatory joint disease and congenital. Types of stiffness include: loss of elbow flexion, loss of elbow extension and loss of forearm rotation. All three have different prognoses in terms of the timing of surgery and the likelihood of restoration of function. Contractures can be classified into extrinsic and intrinsic (all intrinsic develop some extrinsic component). Functional impairment can be assessed medicolegally; however, in clinical practice the patient puts an individual value on the arc of motion. Objectively most functions can be undertaken with an arc of 30 to 130 degrees. The commonest cause of a Post-traumatic Stiff elbow is a radial head fracture or a complex fracture dislocation. Risk factors for stiffness include length of immobilisation, associated fracture with dislocation, intra-articular derangement, delayed surgical treatment, associated head injury, heterotopic ossification. Early restoration of bony columns and joint stability to allow early mobilisation reduces incidence of joint stiffness. Heterotopic ossification (HO) is common in fracture dislocation of the elbow. Neural Axis trauma alone causes HO in elbows in 5%. However, combined neural trauma and elbow trauma the incidence is 89%. Stiffness due to thermal injury is usually related to the degree rather than the site. The majority of patients have greater than 20% total body area involved. Extrinsic contractures are usually managed with a sequential release of soft tissues commencing with a capsular excision (retaining LCL/MCL), posterior bundle of the MCL +/− ulna nerve decompression (if there is loss of flexion to 100 degrees). This reliably achieved via a posterior incision, a lateral column exposure +/− ulna nerve mobilisation. A medial column exposure is a viable alternative. Arthroscopic capsular release although associated with a quicker easier rehabilitation is associated with increased neural injury. Timing of release is specific to the type of contracture, i.e. flexion contractures after approx. six months, extension contractures ASAP but after four months, loss of forearm rotation less 6 to 24 months. The use of Hinged Elbow Fixators is increasing. The indications include reconstructions that require protection whilst allowing early movement, persistent instability or recurrent/late instability or interposition arthroplasty. Post-operative rehabilitation requires good analgesia, joint stability and early movement. The role of CPM is often helpful but still being evaluated

Aims

Posterior malleolar (PM) fractures are commonly associated with ankle fractures, pilon fractures, and to a lesser extent tibial shaft fractures. The tibialis posterior (TP) tendon entrapment is a rare complication associated with PM fractures. If undiagnosed, TP entrapment is associated with complications, ranging from reduced range of ankle movement to instability and pes planus deformities, which require further surgeries including radical treatments such as arthrodesis.

Aim: To accurately assess cross-sectional areas of the MFLs and distinguish between the mechanical properties of the anterior and posterior meniscofemoral ligaments. Methods: Twenty-eight fresh frozen cadaveric knees were dissected to isolate the lateral meniscus and MFLs, which remained attached to the femur. The cross-sectional areas of MFLs were determined using the Race-Amis. 1. casting method for measurement. The ligaments were then tensile tested in an Instron materials testing machine. The stress and strain in each sample was calculated from measurements of cross sectional area, load applied, and increase in length,. Results: The mean cross sectional area for the anterior MFL (aMFL) was 14.7 mm. 2. (±14.8mm. 2. ) whilst that of the posterior MFL (pMFL) was 20.9mm. 2. (±11.6mm. 2. ). The mean loads to failure were 300.5N (±155.0N) for the aMFL and 302.5N (±157.9N) for the pMFL, with elastic moduli of 281MPa (±239MPa) and 227MPa (±128MPa) respectively. There were no significant differences in structural or material properties between the two MFLs. When compared with the posterior cruciate ligament (PCL), the mean ultimate loads of the MFLs were similar to those of the posterior bundle of the PCL (pPC), and their elastic moduli were analogous to the anterior bundle (aPC). Discussion: This is the first study to distinguish between the properties of the aMFL and pMFL, and indicates that both ligaments must be given equal consideration when formulating hypotheses on function. The aMFL and pMFL may also serve mutually distinct functions in the human knee. Previous authors. 2. have commented that the reciprocal tightening and slackening of the aPC (taut in flexion) and pPC (taut in extension) indicates a difference in function of these two components of the PCL. Others. 3. have similarly commented on the reciprocal tightening and slackening of the two MFLs. This may also indicate differing functions for these ligaments. It is proposed that the aMFL supplements the function of the aPC, whilst the pMFL supplements the function of the pPC. This hypothesis stimulates debate on preservation of these structures during PCL reconstruction. Race A., Amis A.A., 1996. Cross-sectional area measurement of soft tissue. A new casting method. Journal of Biomechanics 29(9), 1207–1212. RaceA., Amis A.A., 1994a. The mechanical properties of the two bundles of the human posterior cruciate ligament. Journal of Biomechanics 27(1), (13–24). Friederich N F., O’Brien W., 1990. Functional anatomy of the meniscofemoral ligaments. Fourth Congress of the European Society of Sports Traumatology Knee Surgery and Arthroscopy (ESSKA)

Purpose: We undertook a primarily cadaveric study of trabecular architecture of olecranon to link theory of biomechanics and morphological trabecular patterns of olecranon and secondly compare with real-life trabecular pattern in CT scans. Methods & Results: Eight pairs of ulnae (fresh-frozen bones) were obtained from cadavers following road traffic accidents, aged 25 to 60 (mean 34 years). None suffered from previous pathology of elbow. Half of the ulnae were sliced longitudinally, each slice 2–3 mm thick (Group I), and the other half vertically (Group II). After they were radiographed, orientation of trabeculae was studied. CT scans of 8 patients (Group III), originally performed for investigation of fractures of radial head, were studied for comparison of real life trabecular pattern of olecranon. In Group I, two main sets of trabeculae were observed. The first set consists of three bundles, which arise from anterior cortex and support subchondral area – the posterior third bundle curves and spreads to posterior cortex of olecranon. The second set arises from posterior cortex and terminates under subchondral area. In Group II, trabeculae subtend a 900 angle to articular surface. CT scans of 8 patients (Group III), originally performed for investigation of fractures of radial head, ascertained real-life trabecular pattern of olecranon and confirmed cadaveric observations. Conclusion: Trabeculae of olecranon comprise a set to resist compressive loading and a further set to resist tensile stresses. Thicker trabeculae coincide with maximal loading. Prosthetic design of elbow should take into account the trabecular pattern to facilitate stress absorption

Post-traumatic elbow stiffness is a disabling condition that remains challenging for upper limb surgeons. Open elbow arthrolysis is commonly used for the treatment of stiff elbow when conservative therapy has failed. Multiple questions commonly arise from surgeons who deal with this disease. These include whether the patient has post-traumatic stiff elbow, how to evaluate the problem, when surgery is appropriate, how to perform an excellent arthrolysis, what the optimal postoperative rehabilitation is, and how to prevent or reduce the incidence of complications. Following these questions, this review provides an update and overview of post-traumatic elbow stiffness with respect to the diagnosis, preoperative evaluation, arthrolysis strategies, postoperative rehabilitation, and prevention of complications, aiming to provide a complete diagnosis and treatment path.

Cite this article: Bone Joint Open 2020;1-9:576–584.

Aim: To test the hypothesis that the meniscofemoral ligaments (MFLs) make a significant contribution to resisting anteroposterior and rotatory laxity of the posterior cruciate ligament (PCL) deficient knee. Methods: The anterior and posterior MFLs of eight cadaveric knees were identified using previously described dissection techniques [. 1. ], which were shown not to affect overall knee stability in control studies. These specimens were tested for anteroposterior and rotatory laxity in a materials testing machine. The posterior cruciate ligament was then divided, followed by division of the MFLs. Laxity results were obtained for intact, PCL-deficient and PCL/MFL-deficient knees. Results were analysed using repeated measures analysis of variance and paired t tests. Results: Division of the MFLs in the PCL-deficient knee significantly increased posterior laxity between 15o and 90o of flexion (p< 0.01). Force/displacement measurements revealed that, at 90° flexion, the MFLs contributed to 28% of total resistance to posterior drawer in the intact knee and 70% in the PCL-deficient knee (p< 0.01). There was no effect on rotatory laxity (p> 0.2). Discussion: Previous studies have demonstrated a high prevalence of the MFLs in knees1 and that these ligaments have a strength similar to the posterior fibre bundle of the PCL [. 2. ]. The current in vitro study suggests that they contribute to overall resistance to posterior drawer, especially in the PCL-deficient knee. If this is confirmed in vivo, patients with PCL injuries may have a reduced posterior drawer sign if their MFLs are intact, and this may result in a more stable knee. Thus the MFLs should be accurately identified and assessed during MRI scanning and arthroscopy [. 3. ]. Conclusion: This is the first study demonstrating a function for the MFLs as secondary restraints to posterior drawer in the PCL-deficient knee. The integrity of these structures should be assessed during both MRI scanning and arthroscopy of PCL-injured patients, as this may affect the diagnosis and management of such injuries

Purpose: Subtalar dislocation is an exceptional finding. En bloc dislocation under the talus leads to talocalcaneal talonavicular luxation, generally observed in young active adults. Prognsosis is related to the risk of infection and talar necrosis. We report a retrospective series searching for featues influencing long-term clinical outcome. Material and methods: Between 1984 and 1990, twelve cases of subtalar dislocation were treated in our unit. There were nine lateral and three medial cases. Six lateral dislocations were open injuries, the head of the talus exposed medially. Treatment consisted in emergency orthopaedic reduction associated with debride-ment and closure in case of open injury. Temporary pinning (45 days) between the talus and the calcaneus was used in six cases. There were two lesions of the posterior tibial bundle which were repaired in the emergency setting. A supramalleolar lateral flap (Masquelet) was needed in one patient who developed cutaneous necrosis exposing the anterior tibial. Postoperative immobilisation consisted in a plaster boot for 45 days in all cases. Results: Mean follow-up was ten years. Clinical outcome was good in eleven patients (slightly limited dorsal flexion, 10°) and fair to poor in one. We did not have any case of talar necrosis or subtalar degeneration. Discussion: This series confirms data in the literature. Pure dislocation has as a rule a good prognosis although there is some discrepancy in the literature. In our series, lateral dislocation was more frequent than medial dislocation. Skin opening is frequent and is not a factor of poor prognosis. The absence of talar necrosis is related to preservation of the deltoid branch of the posterior tibial artery and respect of the fibular artery collaterals which supply the posteriolateral tubercle and the tarsal sinus. Emergency reduction of peritalar dislocations eliminates vascular suffering and limits the risk of infection. A temporary talocalcaneal pin is indispensable if the joint is unstable after reduction

Objectives

Malrotation of the femoral component can result in post-operative complications in total knee arthroplasty (TKA), including patellar maltracking. Therefore, we used computational simulation to investigate the influence of femoral malrotation on contact stresses on the polyethylene (PE) insert and on the patellar button as well as on the forces on the collateral ligaments.

Objectives

Malalignment of the tibial component could influence the long-term survival of a total knee arthroplasty (TKA). The object of this study was to investigate the biomechanical effect of varus and valgus malalignment on the tibial component under stance-phase gait cycle loading conditions.