Volume versus outcomes in orthopaedic surgery: a proper perspective is paramount

Vitamin E-blended versus conventional polyethylene liners in prostheses : Prospective, randomized trial with 3-year follow-up

BACKGROUND

Despite continuous technical improvements, polyethylene wear debris induced periprosthetic osteolysis remains the main cause for failure of hip arthroplasty. Progressive oxidation of polyethylene was identified as another risk factor for material failure. To overcome this problem, antioxidants such as vitamin E (alpha-tocopherol) were supplemented by diffusion into the latest generation of polyethylene liners.

OBJECTIVE

The purpose of the present study was to investigate the clinical outcome of patients treated with vitamin E blended highly cross-linked ultra-high molecular weight polyethylene liners (UHMWPE-XE) in comparison with conventional UHMWPE‑X liners by evaluating patient-reported outcome measures (PROM's) at 3‑year follow-up.

METHODS

A total of 143 patients were recruited into this prospective, randomized trial in our academic center. Three years after implantation, 101 patients were examined in the outpatient clinic for follow-up. Of these, 51 (50.5%) received UHMWPE-XE and 50 (49.5%) UHMWPE‑X liners. Clinical outcome was evaluated using Harris-Hip-Score (HHS) UCLA-Score and Hip Disability and Osteoarthritis Outcome Score (HOOS).

RESULTS

There was a significant improvement in all PROM's at one- and three-year follow-up compared to the status before implantation. PROM's did not differ significantly between the first and third year follow-up. Both liner groups showed an equal clinical outcome.

CONCLUSION

The present study demonstrates that the supplementation of vitamin E to polyethylene liners is reliable and safe without showing higher complication rates compared with conventional polyethylene liners. The shortterm clinical outcome of vitamin E-blended (UHMWPE‑XE) is equivalent to those of conventional highly cross-linked polyethylene liners.

Diagnostic Accuracy of Synovial Neopterin, TNF-α and Presepsin in Periprosthetic Joint Infection: A Prospective Study

BACKGROUND

Due to the lack of specificity of conventional diagnostic tools, the prediction of periprosthetic joint infections (PJI) remains challenging. The purpose of this study was to evaluate the accuracy of synovial fluid neopterin, presepsin, and TNF-α as diagnostic parameters and to compare it to the biomarkers recommended in the 2018 definition of periprosthetic hip and knee infection.

METHODS

Between August 2018 and July 2019, a prospective cohort study was conducted in 80 patients with painful hip, shoulder, and knee arthroplasty. In addition to medical history, clinical and laboratory data were gathered. PJI was diagnosed based on the 2018 definition of periprosthetic hip and knee infection. Synovial joint fluid was analyzed for biomarker measurement using standard quantitative enzyme immunoassay kits.

RESULTS

Fifty-three patients (66%) were classified as the aseptic group and twenty-seven patients (34%) as the PJI group. The mean levels of synovial fluid neopterin were significantly higher (p < 0.01) in the PJI group than those in the aseptic group (aseptic 8.3 ± 6.9 vs. PJI 20.9 ± 21.4 nmol/L). The average values of synovial fluid TNF-α and presepsin were not significantly higher in the PJI group than those in the aseptic group (presepsin: aseptic 0.13 ± 0.19 vs. PJI 0.11 ± 0.32 ng/mL, p = 0.08; TNF-α: aseptic 6.6 ± 7.3 vs. PJI 46.3 ± 123.2 pg/mL, p = 0.17). Synovial fluid neopterin was 59% specific and 74% sensitive with a cut-off value of 7.2 nmol/L. The sensitivity and specificity of synovial fluid TNF-α were 63 and 51% with a cut-off value of 3.9 pg/mL. Synovial fluid presepsin was 51% specific and 29% sensitive with a cut-off value above 0.06 ng/mL.

CONCLUSION

Synovial fluid neopterin appears to a reliable diagnostic marker for detection of PJI. In contrast, synovial fluid TNF-α and presepsin are not suitable to exclude or diagnose PJI.

Modular necks in primary hip arthroplasty without anatomical deformity: no clear benefit on restoration of hip geometry and dislocation rate. An exploratory study

Modular necks were introduced in total hip arthroplasty (THA) to improve restoration of hip-geometry and reduce dislocation-rates. This presumed advantage was evaluated retrospectively for patients with arthritis in otherwise anatomically normal hips. Restoration of hip-geometry was assessed on preoperative and postoperative calibrated radiographs in 95 consecutive primary THAs with a modular neck design and compared with 95 match controlled THAs with a similar monoblock stem. No significant differences were seen in restoration of body moment arm, leg length and cupangle. Offset restoration revealed a borderline significant difference (P = 0.48) with higher values for the monoblock stem. In both groups 4 dislocations within one year were encountered. In this study modular necks did not reveal a clear benefit in restoring hip geometry and dislocation rate after straightforward THA.

Excessive polyethylene wear and acetabular bone defects from standard use of a hooded acetabular insert in total hip arthroplasty

PURPOSE

In total hip arthroplasty (THA) the use of a polyethylene (PE) insert with a hooded rim can be considered to reduce dislocation risks. This benefit has to be balanced against the potential introduction of impingement of the femoral component on this rim. We present a case series of early acetabular revisions for excessive PE wear and acetabular bone defects from overuse of such a hooded rim insert.

MATERIAL AND METHODS

Twenty-eight patients with 34 consecutive early acetabular revisions were evaluated on failure mechanism. One type of implant was used in all cases. Standard pelvic radiographs and pre-operative CT scans were used to quantify PE wear, implant positioning and acetabular bone defects.

RESULTS

An acetabular revision with impaction grafting was performed in all cases with a mean cup survival of ten years (range 1.3-19.3). No concurrent stem revisions were necessary. Overall implant positioning was adequate with a mean cup inclination of 45° (range 39-57) and anteversion of 25° (range eight to 45). The mean PE wear was 0.24 mm/year (range 0.00-1.17). The mean acetabular bone defect on pelvic CT scans was calculated as 352 mm² (range zero to 1107) and 369 mm² (range zero to 1300) in the coronal and transversal planes, respectively. A hooded acetabular insert was retrieved in all cases and profound PE wear, typically from the posterior hooded rim, was encountered.

CONCLUSION

The use of hooded acetabular inserts may be considered to improve implant stability intra-operatively. This case series clearly presents that together with these devices, component impingement with concordant complications such as accelerated PE wear may be introduced. Standard use of these stabilizing inserts should thus be avoided.

Simultaneous vs staged bilateral total knee arthroplasty among Medicare beneficiaries, 2000-2009

Simultaneous bilateral total knee arthroplasty (TKA) reportedly has higher postoperative complication rates than staged procedures, but little is known about recent trends and outcomes among Medicare patients. In a 5% national sample of Medicare beneficiaries older than 65 years, we identified 83,441 patients who underwent elective TKA between 2000 and 2009 and compared patients undergoing simultaneous bilateral TKA (n=4519) to staged TKA (n=3788). Use of simultaneous TKA did not change over time (3 in 10,000), but use of staged TKA increased three-fold from 1.4 to 4.4 in 10,000 person-years. We assessed length of stay; 5-year risk of revision; periprocedural (i.e., 90-day) risk of infection; hospitalization for venous thromboembolism (VTE) and myocardial infarction (MI); and death using Kaplan-Meier methods. Simultaneous TKA had higher 90-day risk of death (0.7% vs. 0.3%, P=0.02), VTE (0.9% vs. 0.5%, P=0.07), and MI (0.5% vs. 0.2%, P=0.02). Infection and revision rates were similar between the two groups.

Does surgical volume affect outcome after primary and revision knee arthroplasty? A systematic review of the literature

BACKGROUND

In 2009 there were 72,980 primary and 4565 revision knee arthroplasties performed in England and Wales [1]. Given the large number of procedures done annually any factors that may influence outcome and benefit the patient must be considered seriously.

OBJECTIVES

To find out whether a relationship exists between hospital and surgical volume and patient outcomes for primary and revision knee arthroplasty. A systematic review of the literature was performed to evaluate the current evidence using the PRISMA criteria [2].

DATA SOURCES

A computerised literature search was performed on the electronic databases PubMed, Medline, Embase and CINAHL between 1973 and 2011.

STUDY ELIGIBILITY CRITERIA

All abstracts, in the English language, pertaining to either surgical or hospital volume and outcome after primary and revision knee arthroplasty between 1973 and 2011 were considered. Outcomes of interest included morbidity, mortality, clinical and economic outcomes.

CONCLUSIONS

Both the orthopaedic and surgical specialties literature demonstrates a clear and consistent relationship between both surgeon and hospital volume with outcome, higher volume being associated with improved patient outcomes. In view of the literature consideration should be given to whether all orthopaedic operations should be carried out by all surgeons in all hospitals.

Iatrogenic radial nerve palsy after operative management of humeral shaft fractures

BACKGROUND

It is generally agreed that a period of observation is appropriate for primary radial nerve palsy associated with humeral shaft fractures. There is no consensus, however, with regard to secondary radial nerve palsy, particularly when it is iatrogenic. Most texts state that surgical exploration is indicated for nerve palsy that occurs after fracture manipulation, but our experience suggests that it is not necessary for radial nerve palsy developing after operative management of humeral shaft fractures.

METHODS

A total of 707 humerus shaft fractures were treated operatively at our two hospitals over a 10-year period. Of these, 30 patients sustained iatrogenic radial nerve palsy. Another 16 cases were referred to us with adequate documentation from other institutions. No recognized intraoperative injuries to the radial nerve were recorded in any case.

RESULTS

Of the 46 patients, 21 were female and 25 were male. The median age was 40 years (range, 19-75 years). A total of 39 patients had been treated with dynamic compression plates, 3 with a rigid interlocking intramedullary nail, and 4 with Ender nails. All fractures were diaphyseal, at the middle or distal third level. At the discretion of the surgeon, five cases were surgically explored. In all five cases the radial nerve was in continuity and no macroscopic lesions were noted. All cases eventually recovered grade 4 of 5 muscle strength or better. The median time to the beginning of clinical recovery was 16 weeks (range, 5-30 weeks).

CONCLUSIONS

The timing and pattern of radial nerve recovery in this situation was similar to that seen in primary radial nerve palsy. There appears to be no advantage to early exploration of the radial nerve. In the absence of obviously misplaced instrumentation or fracture displacement, we treat it like a primary palsy and recommend observation for a minimum of 4 months before exploration.

Safety of simultaneous bilateral total knee arthroplasty. A meta-analysis

BACKGROUND

The safety of simultaneous bilateral total knee replacement remains controversial. Some studies have demonstrated a higher rate of serious complications, including death, following bilateral procedures, whereas others have suggested no increase in the complication rate. The objective of this meta-analysis was to compare the safety of simultaneous bilateral total knee replacement with that of staged bilateral and unilateral total knee replacements.

METHODS

A computerized literature search was conducted to identify all citations, from 1966 to 2005, concerning bilateral total knee replacement. All of the English-language abstracts were obtained. A multistage assessment was then performed to identify articles fulfilling the inclusion criteria for the study. All randomized, prospective studies reporting the outcome of bilateral total knee replacement were included. The details of the reported data were extracted, and an extensive analysis of relevant variables was carried out.

RESULTS

One hundred and fifty published articles were identified, and eighteen that included a total of 27,807 patients (44,684 knees) were included in the meta-analysis. There were 10,930 unilateral total knee replacements, 16,419 simultaneous bilateral total knee replacements, and 458 staged bilateral total knee replacements with at least three months between the operative procedures. The prevalences of pulmonary embolism (odds ratio = 1.8), cardiac complications (odds ratio = 2.49), and mortality (odds ratio = 2.2) were higher after simultaneous bilateral total knee replacement. The prevalence of deep venous thrombosis was lower after simultaneous bilateral total knee replacement, but this difference was not significant. The complication rates after the staged bilateral total knee replacements were similar to those in the patients who had undergone unilateral total knee replacement only.

CONCLUSIONS

Compared with staged bilateral or unilateral total knee replacement, simultaneous bilateral total knee replacement carries a higher risk of serious cardiac complications, pulmonary complications, and mortality. The period of time between staged procedures that would eliminate these increased risks could not be determined from this study.

LEVEL OF EVIDENCE

Therapeutic Level III.

Hospital volume and inpatient mortality outcomes of total hip arthroplasty in the United States

The purpose of this study was to examine the effect of hospital volume on outcomes for primary and revision total hip arthroplasty (THA). The Nationwide Inpatient Sample database was used to identify our patient set. These data include a sample of non-Medicare and Medicare patients who are unique to this study, increasing external validity compared with other studies. Outcome variables examined included in-hospital mortality and prolonged length of stay (PLOS). Primary THA mortality was 0.16% in the highest volume quartile and 0.29% in the lowest volume quartile (P < .001). The rates of PLOS showed improved outcomes in the highest volume hospitals. Similar trends were found for revision THA, with an in-hospital mortality of 1.20% for lowest volume hospitals and 0.48% for highest volume hospitals (P < .001). Hospitals with higher volume had superior inpatient outcomes mortality, PLOS, and discharge disposition for THA and revision arthroplasty.

Increased surgical volume is associated with lower THA dislocation rates

The presumed correlation between an increasing volume of health care procedures and an improvement in outcomes is sometimes referred to as the practice-makes-perfect effect. Growing interest in outcomes-based research has led to numerous papers examining this relationship for various surgical procedures, including total hip arthroplasty. The results of these studies have important implications for consumers, providers, and healthcare financers. Accordingly, we review the literature to date examining surgeon and hospital volume effects on hip arthroplasty outcomes, with a specific focus on the effects of volume on dislocation. A systemic review of the literature demonstrates a substantial positive association between surgical volumes and improvement in most THA outcomes, including dislocation; that is, increasing surgical volume is associated with lower dislocation rates. This correlation appears to be stronger and is more clearly established for surgeon volumes than it is for hospital volumes.

Current practice in the management of anterior cruciate ligament injuries in the United Kingdom

OBJECTIVE

To outline the current practice in the management of anterior cruciate ligament (ACL) injuries in the United Kingdom.

METHODS

A postal questionnaire designed to include various clinical scenarios was sent out to the 321 orthopaedic surgeons in the United Kingdom who, being affiliated to one of the specialist societies of the British Orthopaedic Association, namely the British Association for Surgery of the Knee (BASK) or the British Orthopaedic Sports Trauma Association (BOSTA), have a manifested interest in treating such injuries.

RESULTS

The response rate was 60% (192/321). Most surgeons diagnose and operate on less than 50 ACL injuries a year. The following results were obtained: 58% (76/132) use bone-patellar tendon-bone autografts, whereas 33% (44/132) use semitendinosis/gracilis autografts; 84% (108/129) would not incorporate the ACL remnant in the reconstruction; 14% (19/135) would perform an ACL reconstruction in an 8 year child with an acute rupture; 30% (42/141) would perform an ACL reconstruction in a 14 year old with an acute ACL rupture.

CONCLUSIONS

There is wide variation in the management of acute and chronic ACL injuries among orthopaedic surgeons in the British Isles. Future research and randomised controlled trials should address the issues that this investigation has raised.

Relationship between surgical volume and early outcomes of total hip arthroplasty: do results continue to get better?

This retrospective study explored the relationship between the volume of total hip arthroplasties (THA) and postoperative mortality and early complications from a single institution. One thousand hip arthroplasties in 932 patients were identified during a 1-year period, which included 786 primary and 214 revision hip arthroplasties. The postoperative 6-month combined medical and orthopedic complication rate for primary and revision THA was 7.9% and 16.5%, respectively. The 6-month mortality rate for the overall group was 0.5% (5 deaths), for the primary hips was 0.4% (3 deaths), and for the revision hip was 0.9% (2 deaths). The mortality and complication rates of many surgical procedures, including joint arthroplasties, are inversely related to hospital and surgical volume. The reduction in complication rate, however, approaches a plateau and does not improve regardless of an increase in the surgical and hospital volume.

[Relation between activity volume and surgeon's results: myth or reality?]

The relationship between volume and surgical outcome seems logical, but needs to be demonstrated in the real world. A qualitative systematic review has been conducted to verify this hypothesis. Five systematic reviews and hundred original papers have been retrieved and analysed. Most of the studies were retrospective and used administrative data instead of medical charts. Moreover few studies involved a good case mix adjustment when comparing surgical units or individual surgeons. These methodological flaws do not allow any evidence based conclusions. Even though a positive relationship is suggested for surgical units, the relationship between volume and outcome was however less obvious for an individual surgeon. There is some evidence that the relationship varied greatly according to the specialty or the procedure evaluated. A new approach based on predictive scores comparing expected versus observed outcomes is mandatory and seems to be the best way to assess objectively the relationship between surgical volume and outcomes.