Mark Zhu

Hemiarthroplasty of the Hip with and without Cement: A Randomized Clinical Trial

BACKGROUND Controversy exists regarding the use of cement for hemiarthroplasty to treat a displaced subcapital femoral neck fracture in elderly patients. The primary hypothesis of this study was that use of cement would provide better visual analog pain scores following this procedure in an elderly patient population. METHODS Elderly patients (at least seventy years of age) without severe cardiopulmonary compromise who presented to one institution with a displaced subcapital femoral neck fracture were offered inclusion in the study. One hundred and sixty patients (mean age, eighty-five years) with an acute displaced femoral neck fracture were randomly allocated to hemiarthroplasty with either a cemented Exeter or an uncemented Zweymüller Alloclassic component. Clinical and radiographic follow-up was performed for two years and the outcomes were recorded by a blinded assessor. The main clinical outcome measures were pain, mortality, mobility, complications, reoperations, and quality of life measured with use of validated instruments. RESULTS The mean visual analog pain score at rest did not differ significantly between the groups. The total number of complications was greater in the uncemented group (sixty-three compared with twenty-eight in the cemented group). Subsidence was significantly more common in the uncemented group (eighteen compared with one in the cemented group). Intraoperative or postoperative fracture was also significantly more common in the uncemented group (eighteen compared with one in the cemented group). The mortality rate did not differ significantly between the groups at any time point (thirty-five deaths in the uncemented group compared with thirty-two in the cemented group at two years). The Oxford hip score was significantly poorer in the uncemented group at six weeks (38.8 compared with 35.7 in the cemented group), and it was also poorer or similar at later follow-up time points although the differences were not significant. There was also a trend toward poorer mobility and greater dependence on walking aids in the cemented group. The postoperative Short Musculoskeletal Function Assessment and Mini-Mental State Examination scores did not differ significantly between the groups. CONCLUSIONS In elderly patients (seventy years or older) without severe cardiopulmonary compromise who were treated with hemiarthroplasty for a displaced femoral neck fracture, use of a cemented Exeter implant and use of an uncemented Alloclassic implant provided a comparable outcome with regard to pain. However, implant-related complication rates were significantly lower in the group treated with a cemented implant. Trends toward better function and better mobility in the cemented group were observed. These trends reached significance in particular functional scores at some postoperative time points. LEVEL OF EVIDENCE Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Comparison of functional outcomes of reverse shoulder arthroplasty with those of hemiarthroplasty in the treatment of cuff-tear arthropathy: a matched-pair analysis.

BACKGROUND Rotator cuff-tear arthropathy has traditionally represented a challenge to the shoulder arthroplasty surgeon. The poor results of conventional total shoulder arthroplasty in rotator-cuff-deficient shoulders due to glenoid component loosening have led to hemiarthroplasty being the traditional preferred surgical option. Recently, reverse total shoulder arthroplasty has gained increasing popularity because of a clinical perception of an improved functional outcome, despite the lack of comparative data. The aim of this study was to compare the early functional results of hemiarthroplasty with those of reverse shoulder arthroplasty in the management of cuff-tear arthropathy. METHODS The results of 102 primary hemiarthroplasties for rotator cuff-tear arthropathy were compared with those of 102 reverse shoulder arthroplasties performed for the same diagnosis. Patients were identified from the New Zealand Joint Registry and matched for age, sex, and American Society of Anesthesiologists (ASA) scores. Oxford Shoulder Scores (OSS) collected at six months postoperatively as well as mortality and revision rates were compared between the two groups. RESULTS There were fifty-one men and fifty-one women in each group, with a mean age of 71.6 years in the hemiarthroplasty group and 72.6 years in the reverse shoulder arthroplasty group. The mean OSS at six months was 31.1 in the hemiarthroplasty group and 37.5 in the reverse shoulder arthroplasty group. At the time of follow-up, there were nine revisions in the hemiarthroplasty group and five in the reverse shoulder arthroplasty group. No difference in mortality rate was seen between the two groups. CONCLUSIONS In this unselected population with rotator cuff-tear arthropathy, controlled for age, sex, and ASA score, reverse shoulder arthroplasty resulted in a functional outcome that was superior to that of hemiarthroplasty. Longer-term follow-up is needed to confirm these findings.

Weight-Bearing in the Nonoperative Treatment of Acute Achilles Tendon Ruptures: A Randomized Controlled Trial.

BACKGROUND The rate of Achilles tendon ruptures is increasing, but there is a lack of consensus on treatment of acute injuries. The purpose of this trial was to compare outcomes of weight-bearing casts with those of traditional casts in the treatment of acute Achilles tendon ruptures. METHODS Eighty-four patients with an acute Achilles tendon rupture were recruited over a two-year period. Patients were randomized to be treated with either a weight-bearing cast with a Böhler iron or a non-weight-bearing cast for eight weeks. Patients underwent muscle dynamometry testing at six months, with additional follow-up at one and two years. The primary outcomes that were assessed were the rerupture rate and the time taken to return to work. Secondary outcomes included return to sports, ankle pain and stiffness, footwear restrictions, and patient satisfaction. RESULTS There were no significant differences between groups with regard to patient demographics or activity levels prior to treatment. At the time of follow-up at two years, one (3%) of the thirty-seven patients in the weight-bearing group and two (5%) of the thirty-seven in the non-weight-bearing group had sustained a rerupture (p = 0.62). The patients in the weight-bearing group experienced less subjective stiffness at one year. There were no significant differences in time taken to return to work, Leppilahti scores, patient satisfaction, pain, or return to sports between the groups. CONCLUSIONS Use of weight-bearing casts for the nonoperative treatment of Achilles tendon ruptures appears to offer outcomes that are at least equivalent to those of non-weight-bearing casts. The overall rerupture rate in this study was low, supporting the continued use of initial nonoperative management for the treatment of acute Achilles tendon ruptures. LEVELS OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Periprosthetic Joint Infection Is the Main Cause of Failure for Modern Knee Arthroplasty: An Analysis of 11,134 Knees

BackgroundAlthough large series from national joint registries may accurately reflect indications for revision TKAs, they may lack the granularity to detect the true incidence and relative importance of such indications, especially periprosthetic joint infections (PJI).Questions/purposesUsing a combination of individual chart review supplemented with New Zealand Joint Registry data, we asked: (1) What is the cumulative incidence of revision TKA? (2) What are the common indications for revising a contemporary primary TKA? (3) Do revision TKA indications differ at various followup times after primary TKA?MethodsWe identified 11,134 primary TKAs performed between 2000 and 2015 in three tertiary referral hospitals. The New Zealand Joint Registry and individual patient chart review were used to identify 357 patients undergoing subsequent revision surgery or any reoperation for PJI. All clinical records, radiographs, and laboratory results were reviewed to identify the primary revision reason. The cumulative incidence of each revision reason was calculated using a competing risk estimator.ResultsThe cumulative incidence for revision TKA at 15 years followup was 6.1% (95% CI, 5.1%–7.1%). The two most-common revision reasons at 15 years followup were PJI followed by aseptic loosening. The risk of revision or reoperation for PJI was 2.0% (95% CI, 1.7%–2.3%) and aseptic loosening was 1.2% (95% CI, 0.7%–1.6%). Approximately half of the revision TKAs secondary to PJI occurred within 2 years of the index TKA (95% CI, 0.8%–1.2%), whereas half of the revision TKAs secondary to aseptic loosening occurred 8 years after the index TKA (95% CI, 0.4%–0.7%).ConclusionsIn this large cohort of patients with comprehensive followup of revision procedures, PJI was the dominant reason for failure during the first 15 years after primary TKA. Aseptic loosening became more important with longer followup. Efforts to improve outcome after primary TKA should focus on these areas, particularly prevention of PJI.Level of EvidenceLevel III, therapeutic study.

Do 'Surgical Helmet Systems' or 'Body Exhaust Suits' Affect Contamination and Deep Infection Rates in Arthroplasty? A Systematic Review

This systematic review examined whether negative-pressure Charnley-type body exhaust suits (BES) or modern positive-pressure surgical helmet systems (SHS) reduce deep infection rates and/or contamination in arthroplasty. For deep infection, four studies (3990 patients) gave adjusted relative risk for deep infection of 0.11 (P = 0.09) against SHS. Five of 7 (71%) studies found less air contamination and 2 of 4 studies (50%) less wound contamination with BES. One of 4 (25%) found less air contamination with SHS and 0 of 1 (0%) less wound contamination. In contrast to BES, modern SHS designs were not shown to reduce contamination or deep infection during arthroplasty.

New Zealand Joint Registry data underestimates the rate of prosthetic joint infection

Background and purpose — Recent studies have revealed deficiencies in the accuracy of data from joint registries when reoperations for prosthetic joint infections (PJIs) are reported, particularly when no components are changed. We compared the accuracy of data from the New Zealand Joint Registry (NZJR) to a multicenter audit of hospital records to establish the rate of capture for PJI reoperations. Methods — 4,009 cases undergoing total knee or hip arthroplasty performed at 3 tertiary referral hospitals over a 3-year period were audited using multiple hospital datasets and the NZJR. The number of reoperations for PJI that were performed within 2 years of the primary arthroplasty was obtained using both methods and the data were compared. Results — The NZJR reported a 2-year reoperation rate for PJI of 0.67%, as compared to 1.1% from the audit of hospital records, giving the NZJR a sensitivity of 63%. Only 4 of 11 debridement-in-situ-only procedures and 7 of 12 modular exchange procedures were captured in the NZJR. Interpretation — The national joint registry underestimated the rate of reoperation for PJI by one third. Strategies for improving the accuracy of data might include revising and clarifying the registry forms to include all reoperations for PJI and frequent validation of the registry data against other databases.

Antibiotic resistance in early periprosthetic joint infection.

Prophylactic antibiotics significantly reduce prosthetic joint infection (PJI) rates after hip and knee arthroplasty. However, rising antibiotic resistance has raised concerns over the adequacy of conventional prophylaxis. This study aimed to identify organisms causing PJIs in hip and knee arthroplasty secondary to perioperative contamination and their susceptibility to current prophylactic antibiotics.

Functional outcome and the structural integrity of arthroscopic Bankart repair: a prospective trial:

Background Recurrent anterior shoulder dislocations are common in young patients with Bankart lesions. Arthroscopic repair is an established treatment; however, recurrent instability occurs in up to 35% of patients. It is unclear whether recurrence is the result of a failure of the surgical repair to heal or a repeat injury. The aim of the present pilot study was to assess radiographic healing of Bankart lesions 6 months post surgical repair and identify any correlations between radiographic findings and subsequent recurrent dislocations. Methods Eighteen patients underwent arthroscopic Bankart repair for recurrent instability. Magnetic resonance (MR) arthrograms were obtained both pre-operatively and 6 months postoperatively. Standard T1 and T2 views were obtained along with an abduction and external rotation (ABER) view. Patients were followed for a minimum of 4 years for the risk of recurrence, and functional outcomes were obtained, including the American Shoulder and Elbow Surgeons Subjective Shoulder Scale, Ontario Shoulder Instability Index, Oxford Shoulder Instability Score and 12-Item Short Form Health Survey. Scores were correlated with pre-operative and postoperative MR findings. Results Six of 18 patients developed recurrent instability. We could not identify correlations between reconstructed labrum (labral bumper) position, failure at suture sites and ABER findings with recurrent instability or functional outcome. Paradoxically, there was a nonstatistically significant trend for patients with no clefts between the labrum and the glenoid at any points along the repair to have worse outcomes than patients with partial or complete clefts. Conclusions In our pilot study, MR arthrogram was used to evaluate the labrum in detail 6 months postoperatively. Despite its proven ability to detect labral lesions, we were unable to demonstrate any features on postoperative MR arthrogram that predicted either functional outcome or recurrent instability. At 6 months post operation, functional recovery and the risk of recurrence may not depend on the anatomical appearance of the labrum alone.

Altered N-methyl D-aspartate receptor subunit expression causes changes to the circadian clock and cell phenotype in osteoarthritic chondrocytes

The chondrocyte circadian clock is altered in osteoarthritis. This change is implicated in the disease-associated changes in chondrocyte phenotype and cartilage loss. Why the clock is changed is unknown. N-methyl-D-aspartate receptors (NMDAR) are critical for regulating the hypothalamic clock. Chondrocytes also express NMDAR and the type of NMDAR subunits expressed changes in osteoarthritis. OBJECTIVE To determine if NMDAR regulate the chondrocyte clock and phenotype. DESIGN Chondrocytes isolated from macroscopically-normal (MN) and osteoarthritic human cartilage were treated with NMDAR antagonists or transfected with GRIN2A or GRIN2B-targetting siRNA. H5 chondrocytes were transfected with GluN2B-expression plasmids. Clock genes and chondrocyte phenotypic markers were measured by RT-qPCR. RESULTS PER2 amplitude was higher and BMAL1 amplitude lower in osteoarthritic compared to MN chondrocytes. In osteoarthritic chondrocytes, NMDAR inhibition restored PER2 and BMAL1 expression to levels similar to MN chondrocytes, and resulted in reduced MMP13 and COL10A1. Paradoxically, NMDAR inhibition in MN chondrocytes resulted in increased PER2, decreased BMAL1 and increased MMP13 and COL10A1. Osteoarthritic, but not MN chondrocytes expressed GluN2B NMDAR subunits. GluN2B knockdown in osteoarthritic chondrocytes restored expression of circadian clock components and phenotypic markers to levels similar to MN chondrocytes. Ectopic expression of GluN2B resulted in reduced BMAL1, increased PER2 and altered SOX9, RUNX2 and MMP13 expression. Knockdown of PER2 mitigated the effects of GluN2B on SOX9 and MMP13. CONCLUSIONS NMDAR regulate the chondrocyte clock and phenotype suggesting NMDAR may also regulate clocks in other peripheral tissues. GluN2B expression in osteoarthritis may contribute to pathology by altering the chondrocyte clock.

Total Knee Arthroplasty in the 21st century: Why Do They Fail? A Fifteen-Year Analysis of 11, 135 Knees:

Introduction and Aims: As national total knee arthroplasty (TKA) registries evolve, there is an increasing trend towards publication of hospital and surgeon-level outcome data, with the goal of stimulating efforts to optimise the results of TKA. Such efforts first require understanding of the current mechanisms of TKA failure. Previous reports on revision TKA from tertiary referral centres lack data on the overall denominator, thus the relative importance of each failure mechanism leading to TKA revision over long term follow up remains unclear. The aim of this study was to analyse reasons for revision following primary TKA, and assess their relative frequencies over long-term follow-up. Methodology: 11,134 primary TKA performed between 2000-2015 at one of three tertiary referral hospitals were identified. ‘Failure’ was defined as patients undergoing subsequent revision surgery involving change of of one or more components or reoperation for deep periprosthetic joint infection (PJI). Patients were identified from a combination of the New Zealand National Joint Registry and individual search of patient records and clinical coding (ICD-9 and ICD-10). All relevant clinical records, radiographs, and lab results were obtained from all New Zealand hospitals to identify the primary reason for revision according to a standardised protocol. Results: A total of 357 (3.2%) failures over the 15 year period were identified. Of these, 36% were revised within one year and 56% were revised within 2 years of primary TKA. Periprosthetic joint infection (PJI) encompassed 48% of all reasons for revision, followed by aseptic loosening (15%), secondary patella resurfacing (14%), tibio-femoral instability (9%), stiffness (5%), polyethylene wear (2.5%), periprosthetic fracture (2.3%), patella maltracking (1.9%) and extensor mechanism discontinuity (0.9%). In the first 5 years following primary TKA, the most common reason for revision was PJI (52%), from 5-10 years PJI and aseptic loosening (35% each), and from 10-15 years aseptic loosening (41%). Conclusion: In this large cohort of patients with comprehensive follow up, PJI was the dominant reason for failure particularly in the first 10 years. Aseptic loosening becomes more important after 10 years follow up. Efforts to improve outcomes following primary TKA should focus on these areas, particularly prevention of PJI.