Union of the ulnar styloid fracture as a function of fracture morphology on conventional radiographs

Objective

In a retrospective radiological study, the authors aimed to detect the influence of fracture morphology on the union rate of ulnar styloid fractures associated with distal radial fractures.

Materials and methods

Eighty-two out of 101 ulnar styloid fractures were included in the final statistical analysis. Initially, they were grouped into six different morphological types based on a novel classification system. They were also classified as per the established Fernández and Frykman classification systems. Furthermore, the initial ulnar styloid displacement was measured in conventional anteroposterior radiographs. Union of the ulnar styloid fracture was evaluated after at least 6 months of follow-up.

Results

The current investigators demonstrated that the various ulnar styloid fracture patterns have no significant predictive value for ulnar styloid union. In contrast, it could be attested, that an initial fragment dislocation of greater than 2.4 mm in the conventional AP radiographs has a significantly lower chance of successful union (p?=?0.022).

Conclusion

Initial displacement of the ulnar styloid should be measured in each distal radial fracture with a concomitant ulnar styloid fracture. This could be useful to inform the decision regarding surgical fixation of the ulnar styloid fragment in patients with an unstable distal radioulnar joint (DRUJ) or persistent symptoms at the ulnar aspect of the wrist.     

High-resolution ultrasound evaluation of extrinsic wrist ligaments in patients affected by rheumatoid arthritis

Objectives

To evaluate the ultrasound features of the extrinsic wrist ligaments in rheumatoid arthritis (RA) patients in comparison with healthy volunteers.

Methods

Twenty-one consecutive patients affected by RA (12 men, 9 women; mean age 57?±?14.6 years) were compared with 21 controls (12, 9; 54?±?12.1, respectively). Wrists were evaluated using ultrasound on both palmar and dorsal sides along each ligament, using carpal bones as references. The following ligaments were studied: radioscaphocapitate, radiolunotriquetral, palmar ulnolunate, palmar ulnotriquetral, dorsal radiotriquetral, dorsal ulnotriquetral, and radial collateral ligament. Ligament number and thickness were noted. Echotexture was rated as fibrillar, fragmented, or heterogeneous; the surface was rated as smooth or blurred.

Results

The number of palmar ulnolunate and palmar ulnotriquetral ligaments detected by ultrasound in patients was significantly lower than in controls (P?=?0.031 and P?=?0.037, respectively). All ligaments had significantly more fragmented or heterogeneous echotexture and blurred surface and were significantly thinner in patients than in controls (P?Conclusions Extrinsic wrist ligaments were less detectable and thinner in patients affected by RA compared with healthy volunteers matched for age and sex. Ligament thinning did not directly correlate with RA duration and clinical parameters.

Key Points

? Ultrasound is increasingly used to evaluate normal anatomy of extrinsic wrist ligaments. ? Extrinsic wrist ligaments are thinner in rheumatoid arthritis patients than in controls. ? Extrinsic wrist ligaments are less easy to detect in rheumatoid arthritis patients. ? Ligament thinning and detectability are not related to clinical parameters.     

Anatomical study of the dorsal cutaneous branch of the ulnar nerve using ultrasound

Objectives

To determine whether ultrasound allows precise assessment of the course and relations of the dorsal cutaneous branch of the ulnar nerve (DCBUN).

Methods

This work, initially undertaken in cadavers, was followed by high-resolution ultrasound study in 20 healthy adult volunteers (40 nerves) by two musculoskeletal radiologists in consensus. Location and course of the DCBUN and its relations to adjacent anatomical structures were analysed.

Results

The DCBUN was consistently identified along its entire course by ultrasound. Mean cross-sectional area of the nerve was 1.6 mm² (range 1.1–2.2). The level at which the DCBUN branches from the ulnar nerve was located a mean of 57 mm (range 40–80) proximal to the ulnar styloid process and 11 mm (range 7–15) radial to the medial border of the ulna. The DCBUN then crossed the medial border of the ulna a mean of 14 mm (range 6–25) proximal to the ulnar styloid process.

Conclusion

The DCBUN is clearly depicted by ultrasound. Precise mapping of its anatomical course could have significant clinical applications, such as preventing injury during surgery of the ulnar side of the wrist or helping in the diagnosis of chronic pain of the ulnar side of the hand.

Key Points

? The dorsal cutaneous branch of the ulnar nerve (DCBUN) is often injured. ? The DCBUN originates from the ulnar nerve in the distal third of the forearm. ? It can be clearly depicted by ultrasound. ? The level at which the DCBUN crosses the ulna is variable. ? Precise mapping of its anatomical course could have significant clinical applications.     

The alignment of the knee joint in relationship to age and osteoarthritis

Introduction

The aim of the present study was to describe the changes in the axis of the knee joint in both radiologically osteoarthritic and non-osteoarthritic knees, on the basis of angles measurable in standardized clinical short knee radiographs, in a cross sectional study of an epidemiological cohort.

Design

From the third inclusion of the Copenhagen City Heart Study, 4,151 subjects were selected for standardized radiography of the knees. After censuring the inclusion, the resulting cohort was comprised of 3,488 individuals. Images were analyzed for radiological knee joint osteoarthritis (OA) and the anatomical femorotibial axis of the knee joint was measured.

Results

The prevalence of knee joint OA in males was 27.9 % and 27.5 %, for the left and right knees respectively. In females this was 32.8 % and 36.4 %. The mean knee joint angles were 4.11° in males; and 5.45° in females. A difference of 1.3° was found between the genders. In non-osteoarthritic knees the increase in valgus orientation in relationship to increasing age was found to be 0.03° and 0.04° per year, respectively, for males and females. Likewise, Kellgren and Lawrence found that OA was seen to influence a shift towards varus of 0.55°–0.76° per level of OA.

Conclusion

Stratification in accordance with morphological severity of OA documented a clear tendency for the axis of the diseased knees to depart from the mean, primarily in the direction of varus. In knees exhibiting no signs of radiographic osteoarthritis we found a significant relationship between increasing age and a shift in the anatomical axis in the direction of valgus.     

Association between varus alignment and post-traumatic osteoarthritis after anterior cruciate ligament injury

Purpose

To investigate the association between varus alignment and post-traumatic osteoarthritis (OA) after an anterior cruciate ligament (ACL) injury.

Methods

One hundred subjects with an acute complete ACL tear were followed for 15 years. Anterior–posterior radiographs of the tibiofemoral joint were obtained with a knee flexion of 20°, and the patellofemoral joint was examined with skyline view at 50° knee flexion. Joint space narrowing and osteophytes were graded in the tibiofemoral and patellofemoral joints in the injured (ACL) and uninjured knee according to the radiographic atlas of the Osteoarthritis Research Society International. The alignment of the uninjured, contralateral knee was measured at follow-up, using full-limb radiographs of leg with the knee in full extension. Alignment was expressed as the hip-knee-ankle (HKA) angle. Alignment was defined as valgus (HKA ≤178°), neutral (179°–181°) or varus (≥182°).

Results

Data from 68 subjects were included in the analysis. Varus alignment of the uninjured knee at follow-up appeared to be associated with OA of the injured knee 15 years after an ACL injury (odds ratio (95 % confidence interval) 3.9 (1.0–15.8, p = 0.052)).

Conclusions

Varus alignment of the uninjured knee at follow-up may be associated with OA of the injured knee 15 years after an ACL injury.

Level of evidence

II.     

Explorative study of the sensitivity and specificity of the pronator quadratus fat pad sign as a predictor of subtle wrist fractures

Objective

To investigate the value of post-traumatic pronator quadratus (PQ) fat pad sign as a reliable predictor of subtle wrist fractures.

Materials and methods

This was a prospective study of 68 patients undergoing X-ray for traumatic wrist injuries and subsequent MRI. The reliability of a positive PQ fat pad sign on X-ray, defined as either raised, interrupted or obliterated, was evaluated in detection of subtle wrist fractures.

Results

Out of 68 patients, 28 had a positive PQ sign without any obvious bony injuries on plain radiographs; of these, the PQ fat pad was obliterated in 11, disrupted in 12, and raised in five cases. Fractures defined as cortical interruption or trabecular fractures were revealed in 13/28 (46 %) patients with a positive PQ sign but only in 7/40 (18 %) patients with a negative sign. With regards to different types of abnormal PQ fat planes, fractures were present in 7/12 patients with a disrupted plane (58 %), 6/11 patients with an obliterated plane (54 %), and none of the patients with a raised plane. The overall sensitivity and specificity of a positive PQ sign in the prediction of occult wrist fractures were 65 and 69 %, respectively.

Conclusions

Our findings indicate that a positive pronator quadratus (PQ) fat pad sign is not a reliable predictor of subtle fractures of the wrist, although we believe that it is a useful radiographic sign in justifying MRI for further clarification of possible joint abnormalities including occult fracture and cortex interruption.     

Feasibility and preliminary results of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction

Purpose

To evaluate the feasibility and performance of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction.

Methods

This prospective study included 28 wrists of 27 patients evaluated with SPECT/CT arthrography and MR arthrography. Iodine contrast medium and gadolinium were injected into the distal radioulnar and midcarpal joints. Late-phase SPECT/CT was performed 3.5 h after intravenous injection of approximately 650 MBq ^99mTc-DPD. MR and SPECT/CT images were separately reviewed in relation to bone marrow oedema, radionuclide uptake, and tears in the scapholunate (SL) and lunotriquetral (LT) ligaments and triangular fibrocartilage complex (TFCC), and an overall diagnosis of ulnar impaction. MR, CT and SPECT/CT imaging findings were compared with each other, with the surgical findings in 12 patients and with clinical follow-up.

Results

The quality of MR arthrography and SPECT/CT arthrography images was fully diagnostic in 23 of 28 wrists (82 %) and 25 of 28 wrists (89 %), respectively. SPECT/CT arthrography was not diagnostic for ligament lesions due to insufficient intraarticular contrast in one wrist. MR and SPECT/CT images showed concordant findings regarding TFCC lesions in 22 of 27 wrists (81 %), SL ligament in 22 of 27 wrists (81 %) and LT ligament in 23 of 27 wrists (85 %). Bone marrow oedema on MR images and scintigraphic uptake were concordant in 21 of 28 wrists (75 %). MR images showed partial TFCC defects in four patients with normal SPECT/CT images. MR images showed bone marrow oedema in 4 of 28 wrists (14 %) without scintigraphic uptake, and scintigraphic uptake was present without MR bone marrow oedema in three wrists (11 %). Regarding diagnosis of ulnar impaction the concordance rate between CT and SPECT/CT was 100 % and reached 96 % (27 of 28) between MR and SPECT/CT arthrography. The sensitivity and specificity of MR, CT and SPECT/CT arthrography were 93 %, 100 % and 100 %, and 93 %, 93 % and 93 %, respectively.

Conclusion

SPECT/CT arthrography of the wrist is feasible. Regarding diagnosis of ulnar impaction we found a high concordance with MR arthrography. SPECT/CT arthrography of the wrist is an alternative to MR arthrography in patients with contraindications to MR imaging.     

Ultrasound of displaced ulnar collateral ligament tears of the thumb: the Stener lesion revisited

Purpose

To retrospectively characterize the ultrasound appearance of displaced ulnar collateral ligament (UCL) tears that are proven at surgery, and then determine the accuracy of the resulting ultrasound criteria in differentiating displaced from non-displaced UCL tears.

Materials and methods

After institutional review board approval, 26 patients were identified from the radiology information system over a 10-year period that had ultrasound evaluation of the thumb and surgically proven UCL tear. Retrospective review of the displaced full-thickness tears was carried out to characterize displaced tears and to establish ultrasound criteria for such tears. A repeat retrospective review 4 months later of all UCL tears applied the criteria to determine accuracy of ultrasound in the diagnosis of displaced full-thickness UCL tear.

Results

The 26 subjects consisted of 17 displaced full-thickness UCL tears, seven non-displaced full-thickness tears, and two partial-thickness tears at surgery. Retrospective ultrasound review of displaced full-thickness tears identified two criteria present in all cases: non-visualization of the UCL ligament and presence of a heterogeneous mass-like area proximal to the first metacarpophalangeal joint. Applying these criteria at the second retrospective review resulted in 100 % sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.

Conclusions

The ultrasound findings of absent UCL fibers and presence of a heterogeneous mass-like abnormality proximal to the first metacarpophalangeal joint achieved 100 % accuracy in differentiating displaced from non-displaced full-thickness UCL tear of the thumb. Displaced full-thickness UCL tears most commonly were located proximal to the adductor aponeurosis.     

Diffusion-weighted MR neurography of median and ulnar nerves in the wrist and palm

Objectives

To investigate the feasibility of diffusion-weighted magnetic resonance neurography (DW-MRN) in the visualisation of extremity nerves in the wrist and palm.

Methods

Thirty-two volunteers and 21 patients underwent imaging of the wrist and palm on a 3-T MR scanner. In all subjects, two radiologists evaluated the image quality on DW-MRN using a four-point grading scale. Kappa statistics were obtained for inter-observer performance. In volunteers, the chi-squared test was used to assess the differences in nerve visualisation on DW-MRN and axial fat-suppressed proton density weighted imaging (FS-PDWI).

Results

In volunteers, the mean image quality scores for the median nerve (MN) and ulnar nerve (UN) were 3.71?±?0.46 and 3.23?±?0.67 for observer 1, and 3.70?±?0.46 and 3.22?±?0.71 for observer 2, respectively. The inter-observer agreement was excellent (k?=?0.843) and good (k?=?0.788), respectively. DW-MRN provided significantly improved visualisations of the second and the third common palmar digital nerves and three branches of UN compared with FS-PDWI (P?<?0.05). In patients, the mean image quality scores for the two observers were 3.24?±?0.62 and 3.10?±?0.83, inter-observer performance was excellent (k?=?0.842).

Conclusions

DW-MRN is feasible for improved visualisation of extremity nerves and their lesions in the wrist and palm with adequate image quality, thereby providing a supplementary method to conventional MR imaging.

Key points

? DW-MRN provides adequate image quality for wrist and palm neurography ? DW-MRN performs similarly to FS-PDWI in nerve visualisation at the wrist ? DW-MRN provides improved visualisation of small nerves in the palm ? DW-MRN serves as a supplementary method to evaluate peripheral neuropathies

     

Computed tomography for the detection of thumb base osteoarthritis: comparison with digital radiography

Objective

To compare computed tomography (CT) with digital radiography for the detection of osteoarthritis (OA) of the first carpometacarpal (CMC1) and scaphotrapeziotrapezoid (STT) joint.

Materials and methods

We retrospectively identified patients who were assessed for CMC1 OA or STT OA at our hand surgery outpatient clinic between January 2008 and March 2011, and who had both a digital radiograph and a CT scan of the hand within a 3-month period. CT and radiographic images were scored independently by two musculoskeletal radiologists for joint space narrowing (JSN), osteophytes, subchondral sclerosis, bone cysts, and erosions in the CMC1 and STT joints.

Results

Thirty patients were identified. The inter-reader reliability of CT for the detection of CMC1 OA (ICC 1.00) and STT OA (ICC 0.80) was higher than radiography (ICC’s 0.15 and 0.45). In comparison with their own radiographical scoring, both readers detected with CT 3 more patients with CMC1 OA, and 13 and 5 more patients with STT OA.

Conclusion

Computed tomography had a higher inter-reader reliability and detection rate for both CMC1 and STT OA, compared with radiography. As surgical treatment selection of thumb base OA depends on the presence of pathology in the CMC1 and STT joints, CT may improve treatment selection and surgical planning.     

Weak associations between structural changes on MRI and symptoms,function and muscle strength in relation to knee osteoarthritis

Purpose

To explore associations between MRI-defined structural abnormalities and clinical features related to knee osteoarthritis (OA).

Methods

Structural and clinical knee OA features were assessed in 87 women (45 with knee OA symptoms). Structural features were quantified by the Kellgren and Lawrence grade on radiography and by the Boston-Leeds Osteoarthritis Knee Score on MRI. Clinical features were assessed using the Knee Injury and Osteoarthritis Outcome Score, functional tests and muscle strength measurements. Associations were examined using regression analyses.

Results

Limited significant associations between structural and clinical features were found. An increased meniscal signal was associated with more pain/symptoms (P < 0.027). An anterior cruciate ligament tear was associated with poorer stair climbing test performance (P = 0.045). In a stepwise linear regression model, patellofemoral cartilage integrity and pain explained 28 % of the isometric quadriceps strength variability. The amount of cartilage lesions, loose bodies and pain explained 38 % of the isokinetic quadriceps strength variability. Synovitis/effusion and patellofemoral cartilage integrity combined with pain explained 34 % of the isometric hamstring strength variability.

Conclusion

Although MRI-detected cartilage lesions, synovitis/effusion and loose bodies did explain part of the muscle strength variability, results suggest that MRI does not improve the link between joint degeneration and the clinical expression of knee OA. MRI contributes less than expected to the understanding of pain and function in knee OA and possibly offers little opportunity to develop structure-modifying treatments in knee OA that could influence the patient’s pain and function.

Level of evidence

Case series with no comparison groups, Level IV.     

Extensor retinaculum of the wrist: gross anatomical correlation with MR imaging after ultrasound-guided tenography with emphasis on anatomical features in wrist dorsiflexion responsible for tendon impingement

Objective

To demonstrate the anatomy of the extensor retinaculum (ER) of the wrist using gross anatomical correlation with magnetic resonance (MR) imaging before and after ultrasound-guided tenography in four different positions, emphasizing the morphological appearance of the ER that occurs with dorsiflexion of the wrist to define the nature of extensor tendon impingement in athletes who perform repetitive wrist dorsiflexion.

Materials and methods

Institutional policies were followed regarding cadaver use. Ten upper extremities were harvested from fresh cadavers. MR imaging before and after ultrasound-guided tenography of the wrist was performed, followed by gross anatomical correlation. Two radiologists interpreted the MR images and sections by consensus for the anatomical landmarks of the ER, and morphological changes occurring during dorsiflexion of the wrist were analyzed and measured.

Results

The ER of the wrist appeared as a band of low signal intensity on T1- and PD-weighted images. Because of its orientation, axial images were best suited to depict the ER anatomy; specifically, localization of the bony landmarks and the septal attachments. On sagittal images, a consistent appearance of the ER was seen: appearing with fusiform morphology in the neutral position, and becoming shortened and thickened at the abutment point where the extensor tendons of the fourth compartment had a curved excursion during dorsiflexion. The width and thickness of the ER in neutral position averaged 13.56 mm and 1.67 mm respectively. In wrist dorsiflexion, the average width and thickness changed to 8.68 mm and 2.15 mm respectively.

Conclusion

Magnetic resonance imaging is a useful technique to demonstrate the ER of the wrist, the septal attachments, and morphological changes that occur during dorsiflexion of the wrist, which potentially can lead to impingement of the extensor tendons.     

C-arm flat-panel CT arthrography of the wrist and elbow: first experiences in human cadavers

Objective

To determine the optimal intra-articular iodine concentration for C-arm flat-panel computed tomography (FPCT) arthrography using advanced joint phantoms and to evaluate its application in human cadaveric wrists and elbows. Multi-detector (MD) CT served as the standard of reference.

Materials and methods

Joint phantoms and 10 human cadaveric wrist and elbow joints were scanned with C-arm FPCT (5-s, 8-s, and 20-s runs) and standard MDCT using different and optimal concentrations of iodinated contrast material. CT numbers of contrast material, tissue, and noise were measured and contrast-to-noise ratios (CNR) calculated for quantitative analysis. Image and depiction of cartilage, bone, and soft tissues were rated. Radiation doses were compared.

Results

In FPCT, iodine concentrations positively correlated with CT numbers and noise of contrast material and with radiation dose (r?=?0.713–0.996, p?<?0.05 each). At an iodine concentration of 45 mg/ml, CNR of cartilage and soft tissues were highest for all FPCT acquisitions and higher than in MDCT. The 20-s FPCT run performed best for image quality and depiction of anatomical structures and was rated overall equal to MDCT (p?=?0.857).

Conclusion

The optimal iodine concentration for C-arm FPCT arthrography in this study is 45 mg/ml, leading to superior CNR and image quality for an optimal FPCT protocol compared with standard MDCT arthrography in human cadaveric joints.     

Intra-articular hylastan versus steroid for knee osteoarthritis

Purpose

To assess the efficacy and safety of one and two intra-articular (IA) injections of the new viscosupplement, hylastan, compared with a single IA corticosteroid injection for pain due to knee osteoarthritis (OA). Hylastan is a high-molecular-weight hyaluronan derivative prepared from bacterial fermented sodium hyaluronate that was developed to remain in the joint for longer than most other viscosupplements.

Methods

This 6-month, double-blind, randomized, parallel group, multicenter trial enrolled patients aged ≥40 years who met American College of Rheumatology criteria for knee OA and had continued pain despite conservative treatment. Patients were randomized 1:1:1 to one of three arms: 2 × 4 mL hylastan (n = 129; arthrocentesis then IA hylastan Day 0, same treatment Week 2); 1 × 4 mL hylastan (n = 130; arthrocentesis then IA hylastan Day 0, arthrocentesis only Week 2); steroid (n = 132; arthrocentesis then IA methylprednisolone acetate 40 mg Day 0, arthrocentesis only Week 2). Participants and evaluators were blinded to treatment. The primary clinical outcome measure was change from baseline in WOMAC A pain score over all postbaseline visits to Week 26.

Results

Statistically significant pain reduction was observed in all three arms, with similar mean (95 % CI) changes in WOMAC A: 2 × 4 mL hylastan ?0.9 (?1.0, ?0.7); 1 × 4 mL hylastan ?0.8 (?0.9, ?0.7); steroid ?0.9 (?1.0, ?0.8); all P < 0.0001 versus baseline. Changes in secondary outcomes (OMERACT-OARSI and WOMAC A responder rates, patient/clinical observer global assessments, and WOMAC A1 walking pain) were similar in all three arms. Target knee adverse events were comparable for all treatments.

Conclusions

Both IA hylastan injection regimens were effective in relieving pain with an acceptable safety profile. IA hylastan did not show a difference versus IA corticosteroid; therefore, the hypothesis of superior pain relief was not met. Further research is needed to compare the efficacy and safety of hylastan with other viscosupplements.

Level of evidence

Therapeutic study, Level I.     

Cadaveric assessment of osteoarthritic changes in the patello-femoral joint: evaluation of 203 knees

Purpose

The purpose of this study was to determine the prevalence, type of lesion, and depth of osteoarthritic (OA) changes in the patello-femoral (PF) joint.

Methods

Two hundred and three cadaveric knees were included in this study with median age of 84 years (54–97). Patella OA lesions were classified using Han’s method: (Type 1) no or minimal lesion, (Type 2) medial facet lesion without involvement of the ridge, (Type 3) lateral facet lesion without involvement of the ridge, (Type 4) lesion involvement of the ridge, (Type 5) medial facet lesion with involvement of the ridge, (Type 6) lateral facet lesion with involvement of the ridge, (Type 7) global lesion. Femoral side OA lesions in the PF joint were classified using modified Chang’s method: (Type 1) no or minimal lesion, (Type 2) medial facet lesion, (Type 3) centre of patella groove lesion, (Type 4) lateral facet lesion, (Type 5) global lesion. OA depth evaluation was performed following Outerbridge’s classification.

Results

OA lesions of the patella were observed as follows: (Type 1) 31 %, (Type 2) 16 %, (Type 3) 3 %, (Type 4) 12 %, (Type 5) 22 %, (Type 6) 2 %, (Type 7) 14 %. Outerbridge’s classification of over Grade 2 OA depth was observed in 75.9 % of subjects. Femoral side OA lesions of the PF joint were observed as follows: (Type 1) 42 %, (Type 2) 20 %, (Type 3) 26 %, (Type 4) 2 %, (Type 5) 11 %. Outerbridge’s classification of over Grade 2 OA depth was observed in 58 % of subjects.

Conclusion

Patella OA and femoral side OA in the PF joint occurred mainly on the medial side. Isolated OA in the lateral facet of the PF joint was exceedingly rare. Female subjects had a greater incidence of severe PF-OA than male subjects, and therefore, the physicians should pay attention when they treat the female subjects not to advance the PF-OA.     

Percutaneous lateral ulnar collateral ligament reconstruction

Purpose

Open surgical reconstruction of the lateral ulnar collateral ligament is the standard treatment for symptomatic posterolateral rotatory instability of the elbow. It involves dissection and retraction of the lateral elbow muscles, which have been shown to be secondary stabilizers of the lateral elbow. We introduce a new muscle-protecting technique for single-strand lateral ulnar collateral ligament reconstruction and report on the isometry and primary stability when compared with a conventional muscle-splitting procedure. It was hypothesized that percutaneous lateral ulnar collateral ligament reconstruction provided isometry over the range of motion and that stability was comparable with a conventional open procedure.

Methods

In sixteen human cadaver arms, the intact and the lateral collateral ligament complex-deficient situation was tested. Open lateral ulnar collateral ligament reconstruction was performed using a single-strand palmaris graft with humeral and ulnar tenodesis screw fixation. Posterolateral rotational stability was compared with a new reconstruction method, which percutaneously places a single-strand palmaris graft with humeral and ulnar tenodesis screw fixation.

Results

Both open and percutaneous lateral ulnar collateral ligament reconstruction provided isometry over the range of motion and restored posterolateral stability to that of the intact situation. No significant differences between open and percutaneous reconstruction were found.

Conclusions

Percutaneous lateral ulnar collateral ligament reconstruction aims to preserve the lateral elbow muscles and to minimize soft tissue dissection. It has been shown that in an in vitro setup, this new procedure provides isometry over the range of motion and sufficiently restores posterolateral rotatory stability.     

Prevalence of cartilage lesions and early osteoarthritis in patients with patellar dislocation

Objectives

Assessment of cartilage lesions and osteoarthritis (OA) of the patellofemoral joint in patients following lateral patellar dislocation using magnetic resonance imaging (MRI).

Methods

MR images of 129 knees (mean age 26?years, range 11–56) grouped as acute (A), recurrent (B), and chronic (C) dislocators were analysed regarding the prevalence and severity of patellofemoral cartilage lesions. Grades of OA were assessed using modified WORMS.

Results

In groups A, B, and C the prevalence of cartilage lesions was 71%, 82%, and 97%, respectively. Most lesions were located on the central patella in groups A and B (central 69% and 78%; medial 56% and 47%; lateral 31% and 42%), whereas group C revealed all regions affected (73%, 61%, and 67%). Of group A, 14% had mild OA and 64% of group B. Group C showed mild OA in 62% and moderate OA in 18%. Cartilage defect size and prevalence of OA was correlated with number of dislocations (r?=?0.41 and r?=?0.59; P?<?0.001).

Conclusions

Cartilage lesions and early OA are common after patellar dislocation and appear to increase with the frequency of dislocation. Both conditions should be considered when interpreting MRI in such patients, because of implications for treatment.

Key Points

? Cartilage lesions are very common after patellar dislocation. ? The severity of cartilage lesions increases with number of dislocations. ? Osteoarthritis is common after recurrent patellar dislocation, even in young patients. ? Detecting cartilage lesions is important after patellar dislocation.     

New mechanism of the posterior elbow dislocation

Purpose

To suggest a new model on the most common kind of posterior elbow dislocation using MRI findings on acute elbow injuries.

Methods

Fifteen patients with simple elbow dislocation (Group A) and 19 patients sustaining pure ligament injuries (Group B) were enrolled in this study. Using MRI scans, bony contusion at radial head and posterior capitellum (lateral bone contusion) and medial aspect of the ulnohumeral joint (medial bone contusion) were investigated with the injury patterns of the collateral ligament and overlying muscles. In Group A, the injury patterns of the ulnar and lateral ulnar collateral ligaments were classified into distraction or stripping type; in Group B, into rupture or strain. Based on these findings, we speculated the injury mechanism of the elbow dislocation.

Results

In Group A, posterolateral (PL) dislocation was found in 12 cases of distractive ulnar collateral ligament type and stripping lateral ulnar collateral ligament type, where lateral bone contusion was found in 11 cases. Posteromedial (PM) dislocation was observed in only two cases of distraction type of the LUCL, where medial bone contusion was seen in two cases. In PL dislocation of the elbow joint, we always found more severe damage of soft tissue at the medial side of the elbow joint compared to the lateral side. Lateral bone contusion was speculated to be caused by bony abutment under pathologic forearm external rotation (PFER) and medial bone contusion, by bony abutment under varus stress. In Group B, the ulnar collateral ligament was more commonly injured than the lateral ulnar collateral ligament, and lateral bone contusion accompanied most cases.

Conclusion

PL dislocation is thought to start from the medial side in contrary to PM dislocation beginning at the lateral side. If the disengagement of the coronoid process is not completed due to the insufficient valgus/varus distraction, a coronoid fracture will develop at the same time as the elbow dislocation during PFER.     

Characterisation of hand small joints arthropathy using high-resolution MRI—Limited discrimination between osteoarthritis and psoriatic arthritis

Objective

To test the hypothesis that microanatomical differences in joint disease localisation could be exploited using high-resolution MRI to better differentiate among rheumatoid arthritis (RA), spondyloarthritis/psoriatic arthritis (SpA/PsA) and osteoarthritis (OA) in clinical practice.

Methods

Sixty-nine patients with suspected inflammatory joint disease of the hand or feet underwent high-resolution MRI using a small loop coil. Images were scored blinded to the clinical status. Various joint changes like periostitis, osteitis, erosions, enthesitis and synovitis were recorded. The image-based diagnosis was compared with the clinical diagnosis.

Results

In 59.4 % of the patients the clinical diagnosis was confirmed on image analysis. This was high for OA (80 %), moderately good for RA (67 %) but only 50 % for SpA/PsA. The major difficulty was to distinguish OA from SpA/PsA where common imaging findings are evident including periostitis (SpA/PsA 45 %, OA 40 % compared with RA 0 %; P?=?0.015). Likewise, osteitis was frequently detected in SpA/PsA (79 %) and OA (80 %) and less frequently in RA (42 %) (P?=?0.014).

Conclusion

Characterisation of inflammatory disorders of small joints merely using high-resolution MRI remains challenging especially in the differentiation between OA and PsA. These findings are likely explained by common microanatomical similarities in disease expression rather than limitations of imaging techniques.

Key Points

? High-resolution MRI is increasingly used to investigate joint disease. ? Osteitis and periostitis occur in psoriatic and osteoarthritis (but not rheumatoid arthritis). ? In severely affected patients the amount of synovitis and erosions is similar.     

Asymmetry of the knee extension deficit in standing affects weight-bearing distribution in patients with bilateral end-stage knee osteoarthritis

Purpose

The aim of this study was to evaluate weight-bearing distribution in patients with bilateral end-stage knee osteoarthritis (OA) and to clarify the gait parameters affecting the weight-bearing distribution during both standing and walking using gait analysis.

Methods

Twenty-five patients (averaged 71 years) with symptomatic bilateral end-stage medial knee OA participated in this study. They performed relaxed standing, placing one foot on a force plate and thereafter, level walking. First, knee resultant force was calculated on bilateral knees during standing. The knees in each patient were divided into Higher and Lower force side for the definition of dominant side limb. Second, gait parameters in each subject were compared between both sides.

Results

Each patient had large weight-bearing asymmetry, though passive range of motion, subjective pain level, femorotibial angle and radiographic disease severities were not significantly different between both sides. In standing, knees on Higher force side were significantly extended (11.2 ± 6.5°) than on Lower force side (14.4 ± 7.3°, P = 0.0086). Similarly, knees on Higher force side were also significantly extended at heel strike during gait. Besides, peak values of extension moment, knee adduction moment, knee adduction moment impulse and vertical force during gait were significantly greater on Higher force side.

Conclusions

Ability to extend the knee in standing was considered to be an essential factor to decide loading condition. It is clinically important to examine the ability to extend the knee in standing when considering loading asymmetry during gait in patients with bilateral knee OA.

Level of evidence

III.