Difference of preoperative varus-valgus stress radiograph is effective for the correction accuracy in the preoperative planning during open-wedge high tibial osteotomy.

PURPOSE: This study aimed to evaluate (1) the efficacy of varus-valgus stress radiographs to adjust the preoperative soft-tissue imbalance and (2) ascertain whether varus-valgus stress radiographs are effective for the correction accuracy in the preoperative planning of the opening wedge high tibial osteotomy (OWHTO). METHODS: From February 2017 to December 2018, a total of 121 consecutive knees that underwent bi-planar OWHTO were enrolled in this retrospective analysis. Preoperative planning was performed using a weight-bearing line (WBL). Target WBL was determined according to the status of the medial compartments such as cartilage, meniscus, and preoperative arthritic grade. Preoperative varus-valgus stress radiographs were used to assess the preoperative mediolateral ligament imbalance. The final target correction length of the opening gap was determined by subtracting the difference between the varus-valgus stress radiographs (VVD). All patients were divided into two groups according to the preoperatively planned correction degree: (group A), smaller than average; (group B), larger than average. Patients were also divided into two other groups (VVD adjusted and neglected groups). RESULTS: Groups A and B were 56 and 54 knees, respectively. The preoperatively planned correction lengths of the opening gap were 9.33 ± 1.5 and 14.16 ± 3.96 mm, respectively (p < 0.01). Mean values of the VVD were 0.85 ± 0.72, and 1.27 ± 1.78 mm, respectively (p < 0.01). Correction errors were 2.17 ± 2.06 and 3.52 ± 2.16%, respectively (p < 0.01). Planned and final correction degrees were also significantly larger (p < 0.01, and p < 0.01, respectively), because the preoperative WBL ratio was significantly smaller in the VVD adjusted group (p < 0.01). CONCLUSION: The VVD values could reproduce the preoperative soft-tissue imbalance and it was more prominent as the correction degree increased. The strategy of subtracting the VVD as assumed soft-tissue imbalance in the preoperative planning worked well for the correction accuracy during OWHTO. LEVEL OF EVIDENCE: Level IV, retrospective study.

Medial unicompartmental knee arthroplasty to patients with a ligamentous deficiency can cause biomechanically poor outcomes.

PURPOSE: The aims of this study were to investigate the biomechanical effects of the deficiency of the collateral ligament and cruciate ligament in medial unicompartmental knee arthroplasty in normal and varus knee patients using computational simulation. METHODS: Validated finite-element (FE) models for conditions of various cruciate and collateral ligament deficiencies were developed to evaluate the biomechanical effects of ligamentous deficiency in UKA for normal and varus knee patients. Contact stresses on the polyethylene (PE) insert, contact stresses on the lateral articular cartilage, and quadriceps force were analyzed under gait-loading conditions. RESULTS: Contact stresses on the PE insert and lateral articular cartilage as well as quadriceps force in a normal knee UKA FE model were increased in the order of anterior cruciate ligament (ACL) deficiency, medial collateral ligament (MCL) deficiency, lateral collateral ligament (LCL) deficiency, and posterior cruciate ligament (PCL) deficiency in the stance phase of gait cycle, as compared with those in the model without ligamentous deficiency. In two or more multiple ligamentous deficiencies, contact stresses on the PE insert and articular lateral cartilage and quadriceps force were significantly increased versus in the case of single-ligament deficiency. CONCLUSION: Poor outcomes of medial UKA in patients with ACL or MCL deficiency can be predicted. Care should be taken to extend the indications when performing medial UKA in patients with ligamentous deficiency, especially when varus knee with ACL or MCL deficiency is present.

The role of the anterolateral ligament in knee's biomechanics: a case-control retrospective study.

PURPOSE: The aim of this study was to assess the functional and clinical results of patients who underwent ACL reconstruction surgery and were divided into subpopulations related to ACL-associated lesions and focused on ALL-associated lesion. METHODS: Our retrospective analysis included 62 patients who underwent standard ACL reconstruction surgery in our hospital from 2014 to 2016. The mean follow-up period was 21 months (range 11-35). We divided the sample into two subpopulations due to the presence or absence of ALL tear at the preoperative MRI. In 42 patients out of 62 (68%), ALL lesion was evident. We evaluated in both subpopulations the ACL failure rate, the functional outcomes rated with IKDC, KOOS, Lysholm scores and the clinical assessment of anteroposterior and rotatory instability with the Lachman test and pivot-shift test. RESULTS: The overall re-injury rate in our cohort of patients was 4.8% with a smaller but not a significant difference between the two groups. A statistically significant difference was observed for the three functional scores, favoring the isolated ACL-lesion group (p < 0.05). Similarly, a better Lachman score was observed in the isolated ACL-lesion group, without statistical significance (p = 0.77); overall, the rate of positive test was lower in the isolated ACL-lesion group. We observed a significant difference of residual rotatory instability (positive pivot-shift test) in the two subpopulations (p = 0.036), and 9% of patients in the ACL + ALL lesion group showed residual jerk or subluxation. CONCLUSION: The additional ALL reconstruction/repair surgery should always be considered in patients with evident ALL tear at the preoperative MRI.

Anterolateral ligament injury has a synergic impact on the anterolateral rotatory laxity in acute anterior cruciate ligament-injured knees.

PURPOSE: To investigate the prevalence of the anterolateral ligament (ALL) injuries and its role in rotatory laxity in acute anterior cruciate ligament (ACL)-injured knees. METHODS: Two-hundred and ninety-six consecutive patients with acute ACL injuries were evaluated retrospectively, excluding those with other ligament injury and undetectable path of ALL in MRI. Patients were divided into two groups based on the degree of ACL injury in arthroscopy (complete versus partial group). Logistic regression and discriminant analysis were performed to assess the risk of pivot shift test. RESULTS: A total of 169 patients were included (128 with complete and 41 with partial ACL rupture). Overall, 106/169 (62.7%) of ALL injuries were characterized, 87/128 (67.9%) in complete group, and 19/41 (46.3%) in partial group. The incidence of pivot shift was 120/128 (93.8%) and 14/41 (34.1%) in the complete and partial groups, respectively. The odds ratio in the pivot shift of combined ALL injury was found as 3.8 (95% CI 1.8-8.4) with the overall ACL injury, but higher as 17.1 (95% CI 3.1-96.4) with partial group. Higher grade of pivot shift showed a greater incidence of injury of ALL. Degree of ACL injury and ALL injury allowed 87.0% of correct classification of subsequent anterolateral rotatory laxity. CONCLUSION: Injury to the ALL could have a synergetic effect on anterolateral rotatory laxity in acute ACL-injured knee, however, its effect might be minor in case of complete tear. Careful assessment about combined ALL injury should be considered, especially in knees with high-grade pivot shift in acute ACL-injured knees. LEVEL OF EVIDENCE: Retrospective prognostic study, Level IV.

Role of the anconeus in the stability of a lateral ligament and common extensor origin-deficient elbow: an in vitro biomechanical study.

BACKGROUND: The role of the anconeus in elbow stability has been a long-standing debate. Anatomic and electromyographic studies have suggested a potential role as a stabilizer. However, to our knowledge, no clinical or biomechanical studies have investigated its role in improving the stability of a combined lateral collateral ligament and common extensor origin (LCL + CEO)-deficient elbow. METHODS: Seven cadaveric upper extremities were mounted in an elbow motion simulator in the varus position. An injured model was created by sectioning of the CEO and the LCL. The anconeus tendon and its aponeurosis were sutured in a Krackow fashion and tensioned to 10 N and 20 N using a transosseous tunnel. Varus-valgus angles and ulnohumeral rotations were recorded using an electromagnetic tracking system during simulated active elbow flexion with the forearm pronated and supinated. RESULTS: During active motion, the injured model resulted in a significant increase in varus angulation (P = .0001 for pronation; P = .001 for supination) and external rotation (P = .001 for pronation; P = .003 for supination) of the ulnohumeral articulation compared with the intact state. Tensioning of the anconeus significantly decreased the varus angulation (P = .006 for 10 N pronation; P = .0001 for 20 N pronation; P = .0001 for 10 N supination; P = .0001 for 20 N supination) and external rotation angle (P = .008 for 10 N pronation; P = .0001 for 20 N pronation; P = .0001 for 10 N supination; P = .0001 for 20 N supination) of the injured elbow. CONCLUSIONS: In the highly unstable varus elbow orientation, anconeus tensioning restores the in vitro stability of a combined LCL + CEO-deficient elbow during simulated active motion with the forearm in both pronation and supination. These results may have several clinical implications in managing symptomatic lateral elbow instability.

Ultrasound-Assisted Assessment of Medial Elbow Stability.

OBJECTIVES: An assessment of medial elbow stability is essential to the patient with an ulnar collateral ligament injury. Ultrasound imaging can be used to assess medial elbow stability. This study determined the effect of the elbow flexion angle on the medial elbow joint space during clinical tests of medial elbow stability. METHODS: Ultrasound images of the nondominant elbow were collected during 3 tests of medial elbow stability: valgus stress test, weighted valgus test, and milking maneuver. The elbow flexion angle increased between the valgus stress test and milking maneuver. The width of the medial joint space was measured on ultrasound images collected in unstressed and stressed conditions. RESULTS: Across test conditions, the medial joint width was greater in the stressed condition (mean ± SD, 3.7 ± 0.1 mm) than in the unstressed condition (2.9 ± 0.09 mm). The medial elbow joint space width was less (mean difference, 0.16 ± 0.01 mm; P = .01) in the milking maneuver position compared to the valgus stress test positions. CONCLUSIONS: This study provides evidence that changes in the width of the medial elbow during clinical evaluation of the unimpaired elbow can be detected by ultrasound. Changing the elbow flexion angle did not affect the change in width of the medial elbow during valgus loading.

In Vitro Kinematic Assessment of a Hinged Elbow Orthosis Following Lateral Collateral Ligament Injury.

PURPOSE: Elbow lateral collateral ligament injuries (LCLI) are often managed with protected mobilization using a hinged elbow orthosis (HEO). The objective of this investigation was to determine the effectiveness of an HEO in stabilizing the elbow following LCLI. METHODS: Seven fresh-frozen cadaveric upper extremity specimens were studied using a custom simulator that enabled elbow motion via computer-controlled actuators and servomotors attached to relevant tendons. Specimens were examined in 4 arm positions (dependent, overhead, horizontal, and varus) and 2 forearm positions (pronation and supination) during both passive and simulated active elbow extension. Specimens were examined before and after simulated LCLI, and then with the addition of an HEO. The lateral collateral ligament, common extensor origin, and lateral elbow capsule were sectioned in the injury model. An electromagnetic tracking system measured ulnohumeral kinematics. RESULTS: The orthosis did not change elbow stability in any arm position during active motion. Muscle activation and forearm pronation enhanced stability in the dependent, horizontal, and varus positions while the HEO was applied. CONCLUSIONS: This HEO does not improve the in vitro stability of the elbow following simulated LCLI. CLINICAL RELEVANCE: An HEO may be safe to use during active motion, but when a patient is not activating the muscles normally (ie, owing to fatigue or cognitive impairment) and the arm is in positions in which the weight of the orthosis might increase joint distraction, an HEO may be harmful. If an HEO is used, the forearm should be braced in pronation following LCLI.

The contribution of the posterolateral capsule to elbow joint stability: a cadaveric biomechanical investigation.

BACKGROUND: Elbow posterolateral rotatory instability occurs after an injury to the lateral collateral ligament complex (LCLC) in isolation or in association with an osteochondral fracture of the posterolateral margin of the capitellum (Osborne-Cotterill lesion [OCL]). The contribution to elbow stability of the posterolateral capsule, attached to this lesion, is unknown. This study quantified the displacement of the radial head on simulated posterior draw with sectioning of the posterior capsule (a simulated OCL) or LCLC. METHODS: Biomechanical testing of the elbow was performed in 8 upper limb cadavers. With the elbow 0°, 30°, 60°, and 90° degrees of flexion, posterior displacement of the radius was measured at increments of a load of 5 N up to 50 N. A simulated OCL and LCLC injury was then performed. RESULTS: A simulated OCL results in significantly more displacement of the radial head compared with the intact elbow at 30° to 60° of elbow flexion. LCLC resection confers significantly more displacement. An OCL after LCLC resection does not create further displacement. CONCLUSIONS: The degree of radial head displacement is greater after a simulated OCL at 30° to 60° of flexion compared with the intact elbow with the same load but not as great as seen with sectioning of the LCLC. This study suggests that the posterior capsule attaching to the back of the capitellum is important to elbow stability and should be identified as the Osborne-Cotterill ligament. Clinical studies are required to determine the importance of these biomechanical findings.

Surgical management of lateral epicondylitis combined with ligament insufficiency.

BACKGROUND: Lateral collateral ligament (LCL) insufficiency may occur in patients with chronic lateral epicondylitis (LE). We report on 14 consecutive patients with chronic LE and LCL insufficiency. METHODS: We performed a retrospective review of 14 patients with LE and LCL insufficiency diagnosed between 2006 and 2015. The patients had undergone débridement for LE and ligament reconstruction for LCL insufficiency. The study included 9 men and 5 women with an average age of 53 years (range, 41-69 years). The mean follow-up period was 36 months (range, 24-97 months). We analyzed the pain visual analog scale score; Mayo Elbow Performance Score; Disabilities of the Arm, Shoulder and Hand score; range of motion; and posterolateral rotatory drawer test. We compared histories of steroid injection, trauma, and surgery. RESULTS: The pain visual analog scale score, Mayo Elbow Performance Score, and Disabilities of the Arm, Shoulder and Hand score were significantly improved postoperatively and improved in all patients. Three patients had mild instability on the stress test at final follow-up. All patients had a history of steroid injection, 2 had a history of trauma, and 3 had a history of surgery. The number of steroid injections and the number of cases receiving steroid injections more than 3 times were significantly higher in patients with LCL insufficiency. CONCLUSIONS: Assessment of stability is important in patients with chronic LE and risk factors such as multiple steroid injections. Simultaneous surgical treatment including open débridement and ligament reconstruction provides satisfactory pain relief and functional improvement in patients with LE and LCL insufficiency.

Influence of Increased Posterior Tibial Slope in Total Knee Arthroplasty on Knee Joint Biomechanics: A Computational Simulation Study.

BACKGROUND: The reconstructed posterior tibial slope (PTS) plays a significant role in restoring knee kinematics in cruciate-retaining-total knee arthroplasty (TKA). A few studies have reported the effect of the PTS on biomechanics. METHODS: This study investigates the effect of the PTS on tibiofemoral (TF) kinematics, patellofemoral (PF) contact stress, and forces at the quadriceps, posterior cruciate ligament (PCL) and collateral ligament after cruciate-retaining-TKA using computer simulations. The simulation for the validated TKA finite element model was performed under deep knee bend condition. All analyses were repeated from -3° to 15° PTS in increments of 3°. RESULTS: The kinematics on the TF joint translated increasingly posteriorly when the PTS increased. Medial and lateral contact points translated in posterior direction in extension and flexion as PTS increased. The maximum contact stress on the PF joint and quadriceps, and collateral ligament force decreased when the PTS increased. An implantation of the tibial plate with increased PTS reduced the PCL load. Physiologic insert movement led to an increasingly posterior position of the femur and reduced quadriceps force especially for knee flexion angles above high flexion (120°) when compared to TKA with a decreased slope of the tibial base plate. CONCLUSION: An increase in the PTS increased medial and lateral movements without paradoxical motion. However, an excessive PTS indicated progressive loosening of the TF joint gap due to a reduction in collateral ligament tension during flexion.

Intra-articular findings in symptomatic minor instability of the lateral elbow (SMILE).

PURPOSE: Lateral epicondylitis is generally considered an extra-articular condition. The role of minor instability in the aetiology of lateral elbow pain has rarely been considered. The aim of this study was to evaluate the correlation of lateral ligamentous laxity with aspects of intra-articular lateral elbow pathology and investigate the role of minor instability in lateral elbow pain. METHODS: Thirty-five consecutive patients aged between 20 and 60 years with recalcitrant lateral epicondylitis who had failed conservative therapy and had no previous trauma or overt instability, were included. The presence of three signs of lateral ligamentous patholaxity and five intra-articular findings were documented during arthroscopy. The relative incidence of each of these was calculated, and the correlation between patholaxity and intra-articular pathology was evaluated. RESULTS: At least one sign of lateral ligamentous laxity was observed in 48.6% of the studied cohort, and 85.7% demonstrated at least one intra-articular abnormal finding. Radial head ballottement was the most common sign of patholaxity (42.9%). Synovitis was the most common intra-articular aspect of pathology (77.1%), followed by lateral capitellar chondropathy (40.0%). A significant correlation was found between the presence of lateral ligamentous patholaxity signs and capitellar chondropathy (p = 0.0409), as well as anteromedial synovitis (p = 0.0408). CONCLUSIONS: Almost one half of patients suffering from recalcitrant lateral epicondylitis display signs of lateral ligamentous patholaxity, and over 85% demonstrate at least one intra-articular abnormality. The most frequent intra-articular findings are synovitis and lateral capitellar chondropathy, which correlate significantly with the presence of lateral ligamentous patholaxity. The fact that several patients demonstrated multiple intra-articular findings in relation to laxity provides support to a sequence of pathologic changes that may result from a symptomatic minor instability of the lateral elbow (SMILE) condition. LEVEL OF EVIDENCE: III.

Residual increased valgus stress angulation and posterolateral rotatory translation after simple elbow dislocation.

PURPOSE: Purpose of this study was to evaluate increased valgus stress angulation and increased posterolateral rotatory translation after simple elbow dislocation and the associated clinical instability. METHODS: Ten patients [three women, seven men; mean age 38 ± 11 years; mean follow-up 54 months (median 47 months; range 23-111 months)] with conservatively treated simple elbow dislocations were included into this study. The elbow function was graded by using the subjective elbow value (SEV), the Oxford Elbow Score (OES), the Mayo Elbow Performance Score (MEPS), as well as the DASH Score. Range of motion (ROM) and clinical signs of valgus and posterolateral rotatory instability (PLRI) were evaluated. Additionally, in all patients sonographic and fluoroscopic evaluation of valgus stress angulation and posterolateral rotatory translation was performed. RESULTS: Functional scores showed excellent to good results in all patients (SEV: 92 %; OES: mean 44 ± 5 points; MES: mean 91 ± 9 points; DASH Score: mean, 4 ± 4 points). The ROM did not reveal any significant differences compared to the non-affected side. Overall, three patients presented signs of clinical instability (valgus instability: n = 1; PLRI: n = 2). Sonographically, a slightly but not significantly increased valgus stress angulation in comparison with the non-affected side was measured (n.s.). The posterolateral rotatory translation was significantly increased compared to the non-affected side (p < 0.05). In this context, sonographically, four of ten patients revealed a valgus stress angulation and seven of ten patients a posterolateral rotatory translation more than 50 % compared to the non-affected. In four patients an increased valgus stress angulation and in four patients an increased posterolateral rotatory translation could be seen fluoroscopically. CONCLUSION: Patients after conservatively treated simple elbow dislocations show good clinical and functional results. However, a sufficient anatomical ligamentary heeling does not exist. LEVEL OF EVIDENCE: IV.

Elbow Instability: Anatomy, Biomechanics, Diagnostic Maneuvers, and Testing.

The elbow comprises a complex of bony and ligamentous stabilizers that provide both primary and secondary constraints to elbow instability. Through trauma and overuse, classic instability patterns arise by loss of these important stabilizers. The diagnosis of elbow instability can made using specific examination maneuvers and testing to diagnose the clinical pattern. This article reviews the elbow's unique anatomy and biomechanical characteristics and these are applied when reviewing the maneuvers and testing used to diagnose elbow instability.

Dorsoradial Instability of the Thumb Metacarpophalangeal Joint: A Biomechanical Investigation.

PURPOSE: To define the role of the dorsal capsule and associated dorsal fibrocartilage (DFC) and their interactions with the radial collateral ligament (RCL) as a thumb metacarpophalangeal (MCP) joint stabilizer. METHODS: Eight cadaveric thumbs were mounted onto a custom jig with 20 N of muscle load applied. The thumb position in space was digitized to measure ulnar-radial, pronation-supination, and volar-dorsal laxity at 0°, 30°, and 60° MCP joint flexion. Serial sectioning was performed and measurements were repeated for the intact state, proper RCL insufficiency, proper and accessory (complete) RCL insufficiency, complete RCL with 50% DFC (radial) insufficiency, and complete RCL with complete DFC insufficiency. RESULTS: Ulnar-radial deviation, pronation-supination, and volar-dorsal translation significantly changed at 30° and 60° MCP joint flexion when comparing complete RCL insufficiency with complete RCL with 50% DFC insufficiency. At 30° flexion, significant increases were found in ulnar deviation, pronation, and volar translation, and there was a decrease in supination. At 60° flexion, ulnar deviation, pronation, and volar translation increased and radial deviation decreased significantly. At 30° flexion, the resting position significantly pronated and translated volarly. At 60° flexion, the resting position significantly shifted ulnarly, pronated, and translated volarly. CONCLUSIONS: The DFC acts as a secondary stabilizer of the thumb MCP joint, working in tandem with the RCL. It acts by stabilizing the MCP joint dorsoradially when external forces are applied across the joint. This cadaveric study shows that RCL insufficiency with a concomitant DFC injury is less likely to be stable than RCL injuries alone, and that this effect is more pronounced with MCP joint flexion. CLINICAL RELEVANCE: Increasing incompetence of the secondary stabilizers of the RCL, such as the DFC, will likely result in increased clinical instability upon physical examination. The results of this study also suggest the need to consider repair of the DFC at the time of RCL repair.

Role of the lateral collateral ligament in posteromedial rotatory instability of the elbow.

BACKGROUND: Posteromedial rotatory instability (PMRI) of the elbow consists of an anteromedial coronoid fracture with lateral collateral ligament (LCL) and posterior bundle of the medial collateral ligament (PMCL) tears. We hypothesized that the LCL tear is required for elbow subluxation/joint incongruity and that an elbow affected by an anteromedial subtype 2 coronoid fracture and a PMCL tear exhibits contact pressures different from both an intact elbow and an elbow affected by PMRI. MATERIALS AND METHODS: Six cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and to passively flex the elbow from 0° to 90° and measure joint contact pressures. After testing of the intact specimen (INTACT-elbow), an anteromedial subtype 2 coronoid fracture with a PMCL tear (COR+PMCL-elbow) and a PMRI injury (PMRI-elbow), after adding an LCL tear, were tested. The highest values of mean contact pressure were used for the comparison among the 3 groups. RESULTS: Neither subluxation nor joint incongruity was observed in the COR+PMCL-elbow. The addition of an LCL detachment consistently caused subluxation and joint incongruity. Mean contact pressures were higher in the COR+PMCL-elbow compared with the INTACT-elbow (P < .03) but lower than in the PMRI-elbow (P < .001). CONCLUSIONS: The LCL lesion in PMRI is necessary for elbow subluxation and causes marked elevations in contact pressures. Even without subluxation, the COR+PMCL-elbow showed higher contact pressures compared with the INTACT-elbow. Treatment of PMRI should be directed toward prevention of joint incongruity, whether by surgical or nonsurgical means, to prevent high articular contact pressures.

Minimal effect of patella eversion on ligament balancing in cruciate-retaining total knee arthroplasty.

PURPOSE: The effect of patellar eversion on ligament laxity measurements is still unclear. The purpose of this study was to investigate the influence of patellar eversion on medial and lateral ligament laxity measurements performed intra-operatively in total knee arthroplasty (TKA). METHODS: A total of 49 knees (27 female) with mean age 70 years (42-83) and mean body mass index of 28.5 were operated consecutively with a cruciate-retaining prosthesis. Medial and lateral ligament laxity in extension and in 90° of flexion was measured with the spatula-method intra-operatively after implantation of the prosthetic components with the patella everted and thereafter with the patella repositioned. The corresponding changes in gap height and inclination were calculated. RESULTS: A statistically significant increase of 0.6 mm (p < 0.001) in ligament laxity (condylar lift-off) laterally in flexion was found with the patella repositioned compared to everted. No differences were found in extension or medially in flexion. Correspondingly, the flexion gap increased by 0.4 mm (p < 0.001) and the flexion gap inclination increased by 0.6° (p = 0.002) when the patella was repositioned. CONCLUSIONS: Earlier research has shown that ligament laxity must be at least 1-2 mm to cause inferior function after TKA. In the current study, we found that the effect of patellar eversion on ligament laxity measurements is too small to be considered clinically relevant. PROSPECTIVE STUDY EVALUATING THE EFFECT OF PATIENT CHARACTERISTICS: Level II.

The Unstable Elbow: Current Concepts in Diagnosis and Treatment.

Elbow instability is common and may occur after a variety of injuries, including falls or direct blows. Instability can be classified as either acute or chronic. Acute instability is classified as simple (without fracture) or complex (with associated fracture). Chronic instability is classified as a chronically dislocated or recurrently unstable elbow. Recurrent instability commonly presents as isolated medial or lateral collateral ligament insufficiency. A chronically dislocated elbow is often more complex, involving both osseous and ligamentous injuries. The treatment of simple dislocations typically involves closed reduction and nonsurgical management. Chronic recurrent lateral and medial collateral ligament insufficiencies have very different clinical characteristics, but definitive treatment frequently involves ligament reconstruction. Complex instability usually requires surgery, which includes open reduction and internal fixation of coronoid and olecranon fractures, repair or replacement of radial head fractures, and lateral collateral ligament repair. Medial collateral ligament repair and/or external fixation are rarely required to restore stability. It is important for surgeons to understand current concepts in the diagnosis and management of acute and chronic elbow instability as well as the preferred surgical treatments and techniques for the management of these injuries.

Treatment of a medial collateral ligament sprain using prolotherapy: a case study.

Prolotherapy is effective in treating refractory tendinopathies, but inadequate clinical evidence exists to recommend its use as a treatment for acute or chronic, medial collateral ligament (MCL) injuries. The current case study documents an illustrative case of a rugby player who had a grade 2 sprain of the MCL and shows the clinical and radiological outcomes following injections of 15% dextrose combined with 0.2% lidocaine. In his case, the prolotherapy, together with an exercise therapy, lasted 3 wk. At the end of the 3 wk, the patient was pain free, with a full range of motion (ROM), and he was able to perform all rugby-specific movements. The mean duration for recovery with conservative treatment of isolated, complete tears of the MCL is normally 4-8 wk.

Restoration of constitutional alignment in TKA leads to more physiological strains in the collateral ligaments.

PURPOSE: Currently, controversy exists whether restoration of neutral mechanical alignment should be attempted in all patients undergoing TKA. Our hypothesis was that restoration of constitutional rather than neutral mechanical alignment may in theory lead to a more physiological strain pattern in the collateral ligaments; therefore, it could potentially be beneficial to patients. Thus, the aim of this study was to measure collateral ligament strains during three motor tasks in the native knee and compare them with the strains noted after TKA in different post-operative alignment conditions. METHODS: Six cadaver specimens (approval number ML4190 from the Research Ethics Committee of University of Leuven, Belgium) were examined using a validated knee kinematics rig under physiological loading conditions. The effect of coronal malalignment was evaluated by using custom-made tibial implant inserts that induced different alignment conditions. The study of six specimens allows us to show that a difference in the mean strains in MCL and LCL of 3.6 and 5.8 %, respectively, was statistically significant with a probability (power) of 0.8. RESULTS: The results indicated that after TKA insertion, the strains in the collateral ligaments closely resembled the pre-operative pattern of the native knee specimens when constitutional alignment was restored. Restoration to neutral mechanical alignment was associated with greater collateral strain deviations from the native knee. CONCLUSION: Based upon this study, it was concluded that restoration of constitutional alignment within a "safe zone" of ±2° during TKA leads to more physiological peri-articular soft tissue strains during loaded as well as unloaded motor tasks.

High-volume image-guided injection for recalcitrant medial collateral ligament injuries of the knee.

AIM: To evaluate the effectiveness of a novel injection technique in the management of recalcitrant medial collateral ligament (MCL) injuries of the knee. MATERIALS AND METHODS: The injection, comprising 10 ml local anaesthetic with 25-50 mg hydrocortisone, is directed beneath the periosteal attachment of the MCL. Twenty-eight patients who received the intervention were asked to complete a questionnaire, a visual analogue scale (VAS) and the International Knee Documentation Committee (IKDC) subjective knee form to quantify symptoms pre-injection and at follow-up. Data were assessed using descriptive statistics. Further analysis was conducted using the Wilcoxon signed-rank test and Fisher's exact test. RESULTS: Sixty-eight percent (n = 19) of patients responded. Three patients were excluded according to the exclusion criteria. Of those studied, 37.5% (n = 6) were professional athletes. At follow-up, patients reported a mean improvement on the VAS of 75.5% (SD = 23.6). There was a significant improvement in IKDC scores (mean difference 42%, SD = 14.2) pre- and post-injection (Wilcoxon signed-rank test, p < 0.001). No residual symptoms were reported by 50% (n = 8) of patients, and a further 37.5% (n = 6) of patients had improved. Of those patients who played sport, two-thirds (n = 10) had returned to their previous level of sport at follow-up, including all of the professional athletes. CONCLUSION: Periosteal high-volume image-guided injection is a useful treatment for recalcitrant MCL injury. Results are encouraging, particularly amongst the professional athletes studied.