Unexplained Pain Post Total Knee Arthroplasty With an Oxford Knee Score ≥20 at 6 Months Predicts Good 2-Year Outcome.

BACKGROUND: Total knee arthroplasty (TKA) is an effective procedure for end-stage osteoarthritis of the knee. Some patients experience persistent unexplained pain post-TKA despite normal investigations. The purpose of this study is to identify which of these patients are likely to improve without any surgical intervention. We hypothesize that patients with unexplained persistent pain and a poor 6-month Oxford knee score (OKS) post-TKA can improve at 2 years. METHODS: Prospectively collected data for all primary unilateral TKA performed from June 2004 to January 2012 were analyzed to identify which patients with unexplained pain at 6 months will improve at 2 years. Patients were included if they had persistent pain and an OKS <27 at 6 months; normal radiological and clinical investigations; no infection identified; surgery performed for primary osteoarthritis. Two hundred sixty patients with OKS <27 at 6 months were analyzed. These patients were subdivided into 2 groups (group 1: 6-month OKS 20-26, group 2: 6-month OKS less than 20). RESULTS: One hundred ninety-one out of 208 (92%) patients in group 1 experienced improvement in pain and outcome at 2 years. Most of the group 1 patients attained a minimal clinically important difference in OKS of at least 5 (P < .001) at 2 years. Group 1 patients also reported better Knee Society Functional Score and Short Form Survey 36 mean scores at 2 years. CONCLUSION: In patients with unexplained pain, an OKS of at least 20 at 6 months predicts good functional outcome at 2 years.

Evaluation of medial-lateral stability and functional outcome following total knee arthroplasty: results of a single hospital joint registry.

A precept of a successful total knee arthroplasty (TKA) would be a well balanced, stable knee. We analyzed the effects of medial-lateral (ML) stability on functional outcome at 2years post-operatively. Prospectively collected Joint Registry data of all unilateral primary TKAs between 2004 and March 2008 were used. ML stability (Group 1: <5°, Group 2: 6°-9°, Group 3: ≥10°) was assessed by 3 independent researchers. 1500 patients undergoing 1507 arthroplasties were divided into their various groups. Outcome assessment involved range of motion (ROM) and functional outcome, using the Knee Society Function Score (KSS), Oxford Knee Score (OKS) and SF-36 score. At 2years, Group 1 patients reported significantly higher KSS (P<0.001) and SF-36 scores. All groups had good post-operative ROM. A stable knee (ML stability <5°) post TKA is likely associated with significantly better functional outcome.

Targeted four-dimensional computerized tomography scans for elbow disorders: a literature review and refinement of existing technique with two exemplar cases.

Background: Four-dimensional computerized tomographies (4D-CTs) or motion CTs in elbow disorders have several potential advantages over conventional static imaging such as a reduction of misdiagnoses, a more targeted surgical approach, better patient understanding of their condition and potentially faster operative times. However, the radiation dose is higher than conventional static CT scans so this should be used judiciously. Our study reviews the current literature for 4D-CTs in dynamic elbow disorders and provides a technical note describing radiation-reduced targeted elbow 4D-CTs (te4D-CT) with two exemplar cases alongside our recommendations for when te4D-CTs are indicated. Methods: te4D-CTs are performed in a lateral decubitus elbow above head position. Preliminary static source axial cut CT obtained with subsequent sagittal and axial planes reconstruction and 3D reconstruction obtained, followed by scan performed in motion and reconstructed to 4D Component. te4D-CTs are taken for either flexion and extension (FE) or pronation and supination (PS) motions depending on the clinical pathology suspected following thorough clinical examination. Results: te4D-CT for PS and FE protocol scans had an effective radiation exposure dose of 0.53 and 0.95mSv, respectively, compared to 1.13-1.83 mSv in conventional elbow 4D-CTs. In addition, te4D-CTs have good diagnostic accuracy provided that the FE or PS pathology is identified carefully by the ordering physician. Conclusion: te4D-CT using isolated pronation and supination, or flexion and extension protocols does come with a significantly reduced radiation dose and can be of equal clinical yield compared with 4D-CTs.

Four-dimensional computed tomography scan for dynamic elbow disorders: recommendations for clinical utility.

BACKGROUND: Four-dimensional computed tomography (4D CT) is rapidly emerging as a diagnostic tool for the investigation of dynamic upper limb disorders. Dynamic elbow pathologies are challenging to diagnose, and at present, limitations exist in current imaging modalities. OBJECTIVE: We aimed to assess the clinical utility of 4D CT in detecting potential dynamic elbow disorders. METHODS: Twenty-eight elbow joints from 26 patients with symptoms of dynamic elbow pathology were included in this study. They were first assessed by a senior orthopedic surgeon with subsequent qualitative data obtained via a Siemens Force Dual Source CT scanner (Erlangen, Germany), producing two- and three-dimensional "static" images and 4D dynamic "movie" images for assessment in each clinical scenario. Clinical assessment before and after scan was compared. RESULTS: Use of 4D CT scan resulted in a change of diagnosis in 16 cases (57.14%). This included a change in primary diagnosis in 2 cases (7.14%) and secondary diagnosis in 14 cases (50%). In 25 cases (89.29%), the 4D CT scan allowed us to understand the pathological anatomy in greater detail which led to a change in the management plan of 15 cases (53.57%). CONCLUSION: 4D CT is a promising diagnostic tool in the management of dynamic elbow disorders and may be considered in clinical practice. Future studies need to compare it with other diagnostic modalities such as three-dimensional CT.

Treatment of infected nonunion total knee arthroplasty periprosthetic fracture using a stemmed articulating spacer.

BACKGROUND: We present a case of multifocal infection involving the left total hip replacement and the right total knee replacement of a patient, further complicated by an infected non-union of a periprosthetic fracture of the right knee. This required the unique simultaneous management of both infection eradication and fracture stabilization in the knee. METHODS: Both sites were treated with a two-stages procedure, including the novel use of a stemmed articulating spacer for the right knee. This spacer was made combining a retrograde humeral nail, coated with antibiotic-impregnated cement, and a pre-formed articulating cement spacer. The patient was able to weight-bear on this spacer. RESULTS: The fracture went on to unite, and a second stage was performed with the use of stemmed prosthesis and augments. She remains infection free two years after the second stage operation. CONCLUSIONS: The use of a stemmed articulating knee spacer can facilitate infection eradication and fracture stabilization while preserving some motion and weight-bearing ability in the two-stages management of an infected periprosthetic fracture of the knee. LEVEL OF EVIDENCE: Level V (Case report).

An atypical presentation of acute pancreatitis after simultaneous bilateral total knee replacement: A case report.

Acute pancreatitis is a known post-operative complication, commonly after abdominal surgery rather than total knee arthroplasty. When complications occur, post total knee arthroplasty, they tend to be cardiovascular and neurological events, rarely involving the gastrointestinal system. Therefore, when gastrointestinal complications occur, especially if they present with atypical symptoms, this tends to result in a delay in diagnosis. We present a case of acute pancreatitis post simultaneous bilateral total knee arthroplasty in a patient with risk factors like alcoholism and hypercholesterolaemia. Its atypical presentation of only persistent tachycardia, without abdominal pain, was misleading and the resultant delay in treatment dangerous. Therefore, it is important to consider acute pancreatitis as a differential diagnosis in a patient with persistent tachycardia post total knee arthroplasty, especially if he has risk factors for the condition.