The Effect of Waiting for a Primary Total Hip Arthroplasty on the Overall Hip Function and Quality of Life

BACKGROUND

The primary aim was to determine whether time spent awaiting primary total hip arthroplasty (THA) affects patient-reported outcome measures (PROMs) using the Oxford Hip score, Harris Hip Score, and visual analogue scale (VAS) pain. The secondary aim was to assess whether patients have worsening HRQoL, while awaiting THA using the European Quality of Life Five Dimension (EQ-5D) index and EQ-5D health VAS.

METHODS

This was a single center cross-sectional study of 190 patients awaiting THA. Patients were divided into waiting "more than 6 months" and "less than 6 months." Baseline and current scores were compared. Multivariate regression analyses were performed to identify predictors of PROM change.

RESULTS

No significant intergroup differences were observed for change in preoperative Oxford Hip score, Harris Hip Score, and VAS pain from index consultation to time of study. The EQ-5D index and EQ-5D health VAS decreased significantly further in patients waiting more than 6 months (P = .043, P = .004). Time awaiting THA was significantly associated with a decrease in EQ-5D index and EQ-5D health VAS in multivariate regression (P = .013, P < .001).

CONCLUSIONS

Waiting more than 6 months is not associated with a decrease in hip-specific PROMs and longer waiting times are not associated with changes in hip-specific PROMs. Waiting time was associated with a decrease in health-related quality of life and patients waiting more than 6 months had significantly higher decreases in EQ-5D scores. This suggests that living longer with hip osteoarthritis leads to a decrease in QoL, not necessarily through perceived osteoarthritis progression.

LEVEL OF EVIDENCE

Level III cross-sectional study.

Better Flexion but Unaffected Satisfaction After Treatment With Posterior Stabilized Versus Cruciate Retaining Total Knee Arthroplasty - 2-year Results of a Prospective, Randomized Trial

BACKGROUND

Both the cruciate-retaining (CR) and posterior-stabilized (PS) implant systems are commonplace in modern total knee arthroplasty (TKA) practice. However, there is controversy regarding functional outcomes and survivorship. The aim of the underlying study was to evaluate differences between CR and PS TKA regarding knee function, patient-reported outcome measures (PROMs) as well as complication rates.

METHODS

140 patients with knee osteoarthritis scheduled for an unconstrained TKA were enrolled in a prospective, randomized study. Patients received either a CR or PS implant. Range of motion and PROMs (Oxford Knee Score, Knee Society Score, European Quality of Life 5 Dimensions 3 Level, University of California Los Angeles Activity scale and subjective satisfaction) were assessed prior to, 3 months, 1 and 2 years after surgery.

RESULTS

We found minor differences between treatment groups regarding demographic factors. Within the PS group duration of surgery was longer (mean PS 81.4 min vs CR 76.0 min, P = .006). We observed better flexion (median PS 120.0° vs CR 115°, P = .017) and an overall better range of motion (median PS 120.0° vs CR 115.0°, P = .008) for the PS group. PROMs did not differ between groups. At 2-year follow-up there were no revisions in either cohort. Five patients needed reoperations. Three patients needed manipulation under anesthesia, 2 in the CR and one in the PS group.

CONCLUSION

While PS TKA achieved a better flexion capability, PROMs were similar in CR and PS TKA. The CR implant design continues to be a reliable option for patients with an intact posterior cruciate ligament.

No difference in patient reported outcome and inflammatory response after coated and uncoated total knee arthroplasty - a randomized controlled study

BACKGROUND

Allergies against implant materials are still not fully understood. Despite controversies about its relevance, some patients need treatment with hypoallergenic implants. This study compared coated and standard total knee arthroplasty (TKA) regarding inflammatory response and patient-reported outcome measures (PROMs).

METHODS

76 patients without self-reported allergies against implant materials were included in a RCT and received a coated or standard TKA of the same cemented posterior-stabilized knee system. 73 patients completed the 3-year follow-up. Two patients died and there was one revision surgery. Serum levels of cytokines with a possible role in implant allergy were measured in patient`s serum (IL-1beta, IL-5, IL-6, IL-8, IL-10, IFN γ, TNF α) prior to, one and three years after surgery. Furthermore, PROMs including knee function (Oxford Knee Score, Knee Society Score) and health-related quality of life (QoL, EuroQuol questionnaire) were assessed. Additionally, 8 patients with patch-test proven skin allergy against implant materials who received the coated implant were assessed similarly and compared to a matched-pair group receiving the same implant.

RESULTS

There were no differences in function and QoL between the assessed groups at any follow-up. The majority of patients demonstrated no elevation of the measured blood cytokines. Cytokine patterns showed no differences between study groups at any follow-up. The allergy patients demonstrated slower functional improvement and minor differences in cytokine pattern. Yet these results were not significant. There were no differences in the matched-pair analysis.

CONCLUSION

We observed no relevant increase in serum cytokine levels in any group. The inflammatory response measured seems limited, even in allergy patients. Furthermore, there were no differences between coated and standard TKA in non-allergy patients in the 3-year Follow-Up period.

TRIAL REGISTRATION

The study protocol was registered in the US National Institutes of Health's database ( http://www.

CLINICALTRIALS

gov ) registry under NCT03424174 on 03/17/2016.

Fulfilment of patients' mandatory expectations are crucial for satisfaction: a study amongst 352 patients after total knee arthroplasty (TKA)

PURPOSE

Patient satisfaction with the results of their total knee arthroplasty (TKA) is one of the primary goals of this elective procedure. Furthermore, the association between the fulfilment of patients' expectations and their satisfaction is well known. The aim of this study was to identify the key expectations of patients awaiting a TKA, evaluate their fulfilment, and compare the outcomes between very and not fully satisfied patients.

METHODS

A prospective cohort study of patients with knee OA scheduled for primary TKA was performed. Pre- and one-year postoperatively patient-reported outcome measures (PROMs) were assessed. Expectations and their fulfilment were evaluated via a questionnaire encompassing 31 expectations. Preoperatively, expectations were indicated as mandatory, desirable and not important. Postoperatively, fulfilment was rated as exceeded, fulfilled, partially or not fulfilled, and not applicable. Satisfaction with the results of TKA was measured with a numeric rating scale (NRS) of 0-10. Discrimination between not fully satisfied and very satisfied patients was set at ≥ 8, as has been proposed recently. To identify independent predictors of this discrimination, a multivariate logistic regression analysis was performed.

RESULTS

Complete data sets of 352 patients were analysed. A set of 17 key expectations was identified. Relief of knee pain was fulfilled the most, and improvement of physical function was fulfilled the least. When asked about overall fulfilled expectations, 40% of patients rated them as exceeded, 34% as fulfilled and 26% as less fulfilled than expected. Not fully satisfied patients showed significantly lower PROMs pre- and postoperatively and less fulfilled key expectations. Higher numbers of exceeded and fulfilled mandatory expectations, higher overall fulfilment and better range of motion (ROM) were significant predictors for satisfaction ≥ 8.

CONCLUSION

Patients' expectations of TKA outcomes were high with equal emphasis on knee-related and general health-related aspects. Their fulfilment was positively associated with satisfaction. Surgeons should ask patients about mandatory expectations for successful TKA and counsel them about the likelihood of their fulfilment to avoid unrealistic expectations.

LEVEL OF EVIDENCE

II.

When are patients with osteoarthritis referred for surgery?

Current treatment strategies in hip and knee osteoarthritis (OA) involve a combined approach that includes not only modification of risk factors and conservative treatment but also joint-preserving surgical therapy in the early stages, or joint replacement in late OA. With the recent development of new etiological concepts (i.e. hip dysplasia and femoroacetabular impingement as major risk factors for hip OA), treatment alternatives for joint preservation could be extended significantly. Satisfactory results of osteotomies and other reconstructive procedures around hip and knee joints can only be expected in early OA (Kellgren/Lawrence grade 0-II). If patients with advanced radiographic OA grades III-IV do not respond to conservative treatment over at least 3 months and express a relevant burden of disease, joint replacement might be considered. Prior to surgery, potential contraindications must be excluded, patient expectations need to be discussed, and modifiable risk factors, which may negatively influence the outcome, should be optimized.

A Novel Multilayer-Coating for Total Knee Arthroplasty Implants is Safe - 10-Year Results From a Randomized-Controlled Trial

BACKGROUND

This randomized-controlled trial was initiated to compare a new multilayer hypoallergenic coating system with the standard implant in total knee arthroplasty (TKA) in terms of serum metal ion levels, patient-reported outcomes (PROs), and implant survival.

METHODS

A total of 120 patients were randomized to receive a coated or standard TKA of the same knee system. Serum metal ion levels (ie, cobalt, chromium, molybdenum, and nickel) as well as knee function (Oxford Knee Score, OKS), quality of life (SF-36), and physical activity (UCLA activity scale) were assessed before surgery and until the 10 year follow-up. A total of 24 patients died and there was one revision in each group. This resulted in 85 patients who completed follow-up.

RESULTS

Both groups demonstrated equally good improvement in PROs after surgery and constant score values thereafter. The majority of patients had metal ion serum levels below detection limit. Only cobalt levels demonstrated a slight increase in the standard group at 5- and 10-year follow-up. However, all patients displayed values below 3 μg/L. The cumulative 10-year survival was 98% in both groups.

CONCLUSION

There were no problems with the new coating system. No relevant increase in metal ion serum levels were measured. A slight increase in cobalt serum levels in the standard TKA was noted, thus not reaching critical values. The new coating system demonstrated equally good PROs as the standard TKA. Excellent implant survival was observed in both groups.

LEVEL OF EVIDENCE

I.

Ask Patients What They Expect! A Survey Among Patients Awaiting Total Hip Arthroplasty in Germany

BACKGROUND

Total hip arthroplasty (THA) is an elective surgery. Therefore, patient satisfaction with the results of surgery is paramount. The association between fulfillment of patients' expectations and satisfaction is well known. The aim of this study was to identify key expectations of patients with hip osteoarthritis awaiting THA.

METHODS

A mixed-methods approach was used, consisting of two sequential parts. The questionnaire was developed based on literature review and focus group interviews. A nationwide survey was conducted in 21 orthopedic departments within Germany.

RESULTS

Out of 691 obtained questionnaires, 636 were analyzed (mean age = 65.7 years (±11.3), 56.1% female). A majority of patients (≥75%) reported more than 20 complaints as 'present' due to hip osteoarthritis. A total of 9 key expectations were identified, which were reported by more than 75% of the patients as 'mandatory' for a successful THA. The identified key expectations were related to pain, range of motion, walking abilities, gait pattern, transitions, leisure and sports activities, awareness of the affected hip, satisfaction with health or life, and compensatory posture. A consistently high correlation was found between the complaints and the corresponding expectations.

CONCLUSION

The expectations of patients have greatly expanded. In this study, a set of mandatory key expectations shared by the majority of patients was identified. The likelihood of fulfillment of key expectations should be assessed for weighing benefits and harms of available treatment options during the indication process. In addition, the results of this study might be used as a resource for shared decision-making.

Indication Criteria for Total Hip Arthroplasty in Patients with Hip Osteoarthritis—Recommendations from a German Consensus Initiative

Background: Osteoarthritis of the hip (hip OA) is a leading cause of pain and disability in elderly people. If non-surgical therapies become ineffective, patients may consider total hip arthroplasty (THA). The biggest challenge in recommending a THA is identifying patients for whom the benefits of this procedure outweigh the potential risks. The aim of this initiative was to develop a clinical practice guideline with accompanying algorithm to guide consultations on THA, supported by a pocket-sized checklist. Methods: The initiative “Evidence- and consensus-based indication criteria for total hip replacement (EKIT-Hip)” used a stepwise approach, starting with an inauguration workshop, where a multidisciplinary German stakeholder panel from various scientific societies agreed on the working process. A Project Coordinating Group (PCG) was formed, and it performed a comprehensive systematic literature search of guidelines and systematic reviews related to the indication criteria for THA, as well as factors influencing outcomes. Based on best-available evidence, preliminary recommendations were formulated by the PCG and discussed with the stakeholder panel during a consensus meeting. In addition, the panel was asked to assess the feasibility of an extracted algorithm and to approve a final checklist. Results: In total, 31 recommendations were approved by 29 representatives of 23 societies. These were used to underpin an algorithm (EKIT-Algorithm), which indicates the minimum requirements for a THA (confirmed diagnosis of hip OA, present and documented individual burden of illness, ineffectiveness of non-surgical therapies, and absence of any contraindications). Once these criteria are fulfilled, further considerations should encompass the medical implications of modifiable risk factors and patients’ individual treatment goals, as discussed during shared decision making. The subsequently developed checklist (EKIT-Checklist) lists relevant criteria for decision making. Conclusions: Adherence to the EKIT-Algorithm, conveniently accessed via the EKIT-Checklist, should improve the standardization of decision making leading to a recommendation for THA. By applying minimum requirements and patient-related risk factors, as well as considering patients’ individual goals, it is possible to identify patients for whom the benefits of THA may exceed the potential risks.

Increased inflammatory response is associated with less favorable functional results 5 years after total knee arthroplasty

PURPOSE

Allergy against implant materials is discussed controversially and still not fully understood. Despite these controversies, a relevant number of patients receive hypoallergenic knee implants. The aim of this study was to compare a new coating system with the standard implant in total knee arthroplasty (TKA). Additionally, the influence of proinflammatory cytokines on patient-reported outcome measures (PROMs) was investigated.

METHODS

120 patients without known metal allergy and without previous metal implants were included. The patients were randomized to receive a coated or standard TKA of the same knee system. 105 patients completed the 5 year follow-up. Patient-reported outcome measures (PROMs) including knee function (Oxford Knee Score, OKS), quality of life (SF36) and UCLA activity scale were assessed. Additionally, several cytokines with a possible role in implant allergy were measured in patient`s serum (IL-1beta, IL-5, IL-6, IL-8, IL-10, IP-10, IFN γ, TNF α). Group comparison was performed using Mann-Whitney U test for continuous values and chi-square test for categorical values.

RESULTS

There were no differences in PROMs between both groups at any follow-up. The majority of patients demonstrated no elevation of the measured blood cytokines. The blood cytokine pattern after 5 years demonstrated no differences between study groups. There was a significant association between elevated IL-8 values and worse results in the overall OKS (p = 0.041), the OKS function component (p = 0.004), the UCLA activity scale (p = 0.007) and the physical component of SF36 (p = 0.001).

CONCLUSION

There were no problems with the new coating during mid-term follow-up and no differences in PROMs between coated and standard TKA. Patients with an increased inflammatory response demonstrated worse functional results, regardless of the implant.

LEVEL OF EVIDENCE

I.

CLINICAL TRIAL REGISTRATION

The study protocol was registered in the US National Institutes of Health's database ( http://www.clinicaltrials.gov ) registry under NCT00862511.

Ultracongruent insert design is a safe alternative to posterior cruciate-substituting total knee arthroplasty: 5-year results of a randomized controlled trial

PURPOSE

If substitution of the posterior cruciate ligament in total knee arthroplasty is necessary, there are two options available: posterior stabilized (PS) design with a post-cam mechanism or anterior-lipped ultracongruent (UC) inserts. UC inserts have the advantage that no femoral box is necessary and a standard femoral component can be used. The aim of this study was to compare the range of motion (ROM) and patient-reported outcome (PRO) after UC and PS fixed-bearing TKA. Better ROM in PS TKA and no difference in PRO between both designs was hypothesized.

METHODS

A randomized controlled trial with 127 patients receiving a fixed-bearing UC or PS design of the same knee system was performed. Nine patients died and there were four revision surgeries. 107 patients completed the 5-year follow-up. Patient-reported outcome was assessed. Patellofemoral problems were evaluated using selected applicable questions of the Oxford Knee Score (getting up from a table, kneeling, climbing stairs).

RESULTS

Surgical time was 10 min shorter in the UC group (p < 0.001). After 5 years, both groups demonstrated good knee function and health-related quality of life without significant differences between the groups. Both groups demonstrated a high satisfaction score and the majority of patients would undergo this surgery again. Patellofemoral problems were recognized more frequently in the PS group (p = 0.025).

CONCLUSION

Both designs demonstrated similar good results after 5 years. Stabilization with an anterior-lipped UC insert can be considered a safe alternative to the well-established PS design if cruciate substitution is necessary.

[The use of knee prostheses with a hypoallergenic coating is safe in the medium term : A randomized controlled study]

BACKGROUND

In Germany, patients with contact allergy to implant components usually receive coated joint arthroplasties. Whether the treatment using these hypoallergenic implants achieves comparable results to standard treatment with implants consisting of cobalt-chromium alloy (CoCr) implants is controversially discussed internationally and has rarely been investigated in the mid-term.

OBJECTIVES

Are there differences in blood metal ion concentrations, knee function, and patient-reported outcomes (PROM) between coated and standard implants?

MATERIAL AND METHODS

118 patients were randomized to receive either a coated or a standard implant. Knee function as well as patient-reported outcome measures were assessed. Metal ion concentrations in blood samples were additionally determined for chromium, cobalt, molybdenum, and nickel, preoperatively, one and five years after surgery.

RESULTS

After five years, it was possible to analyse the results of 97 patients. In metal ion concentrations, as well as PRO, consistently good results were seen, without any difference between the groups. While in 13 patients there was an increase in chromium concentration above 2 µg/l one year after surgery, there was no measured value above 1 µg/l after five years.

CONCLUSION

In our study, similar mid-term results were detected for coated (TiNiN) and standard (CoCr)TKA. With respect to metal ion concentrations and PRO there are no disadvantages in using coated TKA.

Clinical Practice Guideline: Total Hip Replacement for Osteoarthritis–Evidence-Based and Patient-Oriented Indications

BACKGROUND

Total Hip Replacement (THR) belongs to the most common inpatient operations in Germany, with over 240 000 procedures performed per year. 90% of the artificial joints are still functional at 15 years, and up to 60% at 20 years after surgery. It is essential that the indications for such procedures should be uniform, appropriate, and patient-oriented.

METHODS

This review is based on publications retrieved by a systematic literature search for national and international guidelines and systematic reviews on the topic of hip osteoarthritis and THR.

RESULTS

THR should be performed solely with radiologically demonstrated advanced osteoarthritis of the hip (Kellgren and Lawrence grade 3 or 4), after at least three months of conservative treatment, and in the presence of high subjective distress due to symptoms arising from the affected hip joint. Contraindications include refractory infection, acute or chronic accompanying illnesses, and BMI ≥ 40 kg/m2. Patients should stop smoking at least one month before surgery. In patients with diabetes mellitus, preoperative glycemic control to an HbA1c value below 8% is advisable. It is recommended that patients should lower their weight below a BMI of 30 kg/m2.

CONCLUSION

The decision to perform THR should be taken together by both the physician and the patient when the expected treatment benefit outweighs the risks. Evidence suggests that a worse preoperative condition is associated with a poorer surgical outcome.

[Are the results of total knee arthroplasty after high tibial osteotomy worse?]

Hintergrund

Bei einem Teil der Patienten nach Tibiakopfumstellungsosteotomie (HTO) wird die Implantation einer Knietotalendoprothese (Knie-TEP) notwendig. Durch die HTO kann die Anatomie ungünstig verändert und die Knie-TEP-Operation erschwert sein. Ziel dieser Studie war es zu untersuchen, ob Patienten nach HTO gegenüber denjenigen mit primärer Gonarthrose in gleichem Maße von einer Knie-TEP profitieren.

Material und Methoden

Im lokalen Register konnten insgesamt 44 Patienten nach HTO und 1703 Patienten mit primärer Gonarthrose identifiziert werden. Zur Reduktion von Confoundern erfolgte eine 1:1 „propensity score matched-pair“-Analyse (Alter, Geschlecht, BMI, Komorbiditäten) bei Patienten mit einem 5‑Jahres-Follow-up. Es resultierten 35 gematchte Paare, welche hinsichtlich Kniefunktion, Schmerzniveau, Zufriedenheit mit dem Operationsergebnis sowie perioperativen Daten (Schnitt-Naht-Zeit, Implantattyp, Komplikationen) und Revisionen verglichen wurden.

Ergebnisse

Patienten mit vorangegangener HTO hatten prä- und 5 Jahre postoperativ eine vergleichbare Kniefunktion, jedoch ein signifikant höheres prä- und postoperatives Schmerzniveau. Trotz des höheren Schmerzniveaus zeigte sich eine vergleichbare Zufriedenheit mit dem Operationsergebnis. Die Schnitt-Naht-Zeit für die Knie-TEP nach HTO war signifikant länger und es wurden signifikant häufiger modulare Endoprothesen mit Stielverankerung implantiert. Hinsichtlich postoperativer Komplikationen innerhalb der ersten 3 Monate nach Operation unterschieden sich beide Kohorten nicht signifikant. Die Revisionsrate innerhalb von 5 Jahren war bei Patienten nach HTO nicht erhöht.

Schlussfolgerung

Fünf Jahre nach der Knie-TEP zeigten Patienten mit vorangegangener HTO eine vergleichbare Kniefunktion wie Patienten mit primärer Gonarthrose. Jedoch war bei Patienten nach HTO ein höheres Schmerzniveau zu verzeichnen. Der Operationsaufwand der Knie-TEP nach HTO war deutlich höher.

Sports Therapy Interventions Following Total Hip Replacement

BACKGROUND

Sport rehabilitation is a reimbursable intervention assisting reintegration and self-help. In this study, we measured the effects of sport rehabilitation on muscle strength around the hip joint at 1 year after surgery, as well as cardiopulmonary endurance performance and stability of stance, in patients who had undergone a first implantation of a total hip endoprosthesis (total hip replacement, THR) as a treatment for osteoarthritis of the hip.

METHODS

160 patients were randomly allotted either to an intervention group with intensive sport rehabilitation for the first year or to a control group. At three time points (baseline, six and twelve months after surgery), measurements were made of muscular strength around the hip joint (with isokinetic dynamometry), stability of stance, and endurance performance. The primary endpoint was the change in strength of the hip extensors, abductors, flexors, and adductors at twelve months after surgery.

RESULTS

With respect to the primary endpoint, the results were not significantly better in patients who had received sport rehabilitation than in those who had not. At one year, the patients in the intervention group had less pain as measured by the WOMAC pain score (p = 0.023), though the size of this effect was small (r = 0.27). Health-related quality of life was higher in the intervention group at six months, albeit with a small effect size (p = 0.036, r = 0.25); this was no longer demonstrable at one year. The other parameters studied displayed no significant changes.

CONCLUSION

This trial did not demonstrate any significant benefit of sports rehabilitation on functional outcomes in patients who had undergone total hip replacement. Nonetheless, positive trends after the intervention were seen in some parameters. The unexpectedly high dropout rate had been underestimated in the planning phase of the trial; further trials with larger numbers of patients should be performed.

Fulfillment of expectations influence patient satisfaction 5 years after total knee arthroplasty

PURPOSE

Constant efforts have been made to improve prosthesis design in total knee arthroplasty (TKA), but a significant number of patients remain dissatisfied postoperatively. Besides poor improvement in pain or function, poor fulfillment of patients expectations were identified as contributing factors. Purpose of the study was to assess fulfillment of patients' expectations and satisfaction with TKA 5 years after surgery.

METHODS

A total of 103 patients from a prospective randomised study of a high-flexion or standard TKA implant were investigated 5 years after surgery and patient-reported outcomes (PRO), fulfillment of expectations and satisfaction with the result of the surgery were obtained.

RESULTS

There were no differences in PROs, fulfillment of expectations and satisfaction between both implant designs. In total, the patients had high expectations preoperatively, mainly related to pain relief and functional abilities. A total of 89.4% of these expectations were fulfilled. No re-interventions (p < 0.001) and male gender (p = 0.017) were the most important predictors of higher fulfillment of expectations. Satisfaction scored highly at 8.2 out of 10 and most patients (93.2%) would undergo the surgery again. Higher Knee Score (p = 0.012) and fulfillment of expectations (p = 0.002) were correlated with higher satisfaction.

CONCLUSION

Five years after surgery fulfillment of expectations and satisfaction were high regardless of implant design and did significantly influence patient satisfaction. Surgeons should be aware of the importance of patients' expectations and their influence on satisfaction after TKA. Therefore, the probability of fulfillment should be discussed during shared decision making for TKA.

LEVEL OF EVIDENCE

I.

Similar outcome during short-term follow-up after coated and uncoated total knee arthroplasty: a randomized controlled study

PURPOSE

Patients with known hypersensitivity to metals often require hypoallergenic TKA implants. Coating of a standard implant is a common solution, and although in vitro tests have demonstrated reduction of polyethylene wear for these coatings, it is still unknown whether these implants have any clinical benefit. This study was initiated to investigate metal ion concentrations, knee function and patient-reported outcome (PRO) after coated and uncoated TKA.

METHODS

One hundred and twenty-two (122) patients were randomized to receive a coated or a standard TKA and, after exclusions, 59 patients were included in each group. Knee function and PRO were assessed with validated scores up to 3 years after surgery. Metal ion concentrations in blood samples were determined for chromium, cobalt, molybdenum and nickel, preoperatively and 1 year after surgery.

RESULTS

Chromium concentrations in patient plasma increased from a median of 0.25 to 1.30 µg/l in the standard TKA group, and from 0.25 to 0.75 µg/l in the coated TKA group (p = 0.012). Thirteen patients (3 coated, 10 standard TKA) had chromium concentrations above 2 µg/l. The concentrations of cobalt, molybdenum and nickel did not change. Patient-reported outcome measures (PROM) demonstrated a substantial improvement after TKA, without any differences between the groups.

CONCLUSION

The increase in chromium concentration in the standard group needs further investigation. If surgeons use coated implants, they can be confident that these implants perform as well as standard implants.

LEVEL OF EVIDENCE

I.

Analysis of Total Knee Arthroplasty revision causes

Background

The number of revision Total Knee Arthroplasty (TKA) is rising in many countries. The aim of this study was the prospective assessment of the underlying causes leading to revision TKA in a tertiary care hospital and the comparison of those reasons with previously published data.

Methods

In this study patients who had revision TKA between 2010 and 2015 were prospectively included. Revision causes were categorized using all available information from patients’ records including preoperative diagnostics, intraoperative findings as well as the results of the periprosthetic tissue analysis. According to previous studies patients were divided into early (up to 2 years) and late revision (more than 2 years). Additional also re-revisions after already performed revision TKA were included.

Results

We assessed 312 patients who underwent 402 revision TKA, 89.6% of them were referred to our center for revision surgery. In 289 patients (71.9%) this was the first revision surgery after primary TKA. Among the first revisions the majority was late revisions (73.7%). One hundred thirteen patients (28.1%) had already had one or more revision surgeries before. Overall, the most frequent reason for revision was infection (36.1%) followed by aseptic loosening (21.9%) and periprosthetic fracture (13.7%).

Conclusions

In a specialized arthroplasty center periprosthetic joint infection (PJI) was the most common reason for revision and re-revision TKA. This is in contrast to population-based registry data and has consequences on costs as well as on success rates in such centers.

Midterm Results After Coated and Uncoated TKA: A Randomized Controlled Study

Patients undergoing total knee arthroplasty (TKA) who have hypersensitivity to metals usually receive hypoallergenic TKA implants. Coating of a standard implant is a common solution. Although in vitro tests have demonstrated reduction in polyethylene wear for these coatings, it is unknown whether these costly implants have a clinical benefit for patients. One hundred twenty patients undergoing TKA were randomly assigned to receive a novel 7-layer-coating implant or a standard TKA implant. One revision occurred in the standard group, resulting in a calculated 5-year survival of 100% in the coated group and 98.1% in the standard group. The Oxford Knee Score improved substantially in both groups from a mean of 21.6 points preoperatively in the coated group and 21.9 points in the standard group to 39.2 points and 39.2 points, respectively. The current authors observed no adverse effects with the new coating during midterm follow-up. However, longer follow-up time is needed to evaluate possible advantages of this coating. [Orthopedics. 2016; 39(3):S13-S17.].

TKA for Posttraumatic Osteoarthritis Is More Complex and Needs More Surgical Resources

The purpose of this study was to evaluate the surgical effort of total knee arthroplasty (TKA) for posttraumatic osteoarthritis (PTOA) compared with primary osteoarthritis (OA). A total of 1841 TKAs were analyzed, including 170 patients with PTOA, that resulted from soft tissue trauma in 83 patients and fractures in 87 patients. Results showed that patients were significantly younger at the time of surgery in the posttraumatic group (62 vs 71 years; P<.001). Furthermore, fracture was associated with 3.7 years earlier need of TKA compared with soft tissue trauma. Operation time was significantly longer for both of the posttraumatic groups compared with OA (P<.001). Patients undergoing TKA after knee injuries are younger and surgical treatment is more challenging compared with TKA for OA. Extended operation time and implant systems with higher constraint and modular options are required. [Orthopedics. 2016; 39(3):S36-S40.].

How Much Improvement in Patient Activity Can Be Expected After TKA?

Most patients expect an improvement of physical activity after total knee arthroplasty (TKA). The aim of this study was to evaluate improvement in physical activity after TKA. An accelerometer was used to measure activity in 221 patients before and 1 year after TKA. The measurements included the total number of steps and time spent lying, sitting/standing, or walking. Threshold for achievement of health-enhancing physical activity (HEPA) guidelines and step-defined lifestyle were applied to the data. Measured steps per day improved from 5371 to 6587. Only 50 patients (22.6%) met the HEPA guidelines, whereas 31% achieved an active lifestyle. Improvement in daily step number was influenced by age (P<.001), body mass index (P<.001) and preoperative activity (P<.001). After TKA, patients improved in physical activity and one-third achieved an active lifestyle. Patient-specific characteristics and preoperative levels of physical activity had a relevant influence on activity after TKA. [Orthopedics. 2016; 39(3):S18-S23.].

Similar stability and range of motion between cruciate-retaining and cruciate-substituting ultracongruent insert total knee arthroplasty

PURPOSE

The use of an ultracongruent (UC) insert with a standard femoral component for substitution of the posterior cruciate ligament (PCL) is a bone-preserving and therefore interesting alternative to the established box and cam mechanism of posterior-stabilized total knee arthroplasty (TKA). Despite the regular use of these UC inserts, there is little evidence about stability and range of motion (ROM).

METHODS

The aim of this study was to evaluate the stability and ROM in standard cruciate-retaining (CR) and cruciate-substituting UC inserts of the same TKA. In 39 patients, intraoperative measurements of stability and ROM were taken (1) before soft tissue release and bone cuts, (2) after implantation of a CR TKA and (3) after resection of the PCL and substitution with an UC insert. All measurements were taken using a navigation system.

RESULTS

Stability measurements demonstrated no differences between CR (PCL intact) and UC TKA (PCL resected), but significantly increased anteroposterior translation at 60° and 90° of knee flexion compared with the preoperative condition. ROM measurements demonstrated improvement of knee flexion from preoperatively mean 105° (SD 14.1°) to intraoperative 120.2° (SD 6.7°) with the CR and 121.0° (SD 7.5°) with the UC insert and 113.5° (SD 14.0°) at the 1-year follow-up.

CONCLUSION

This study demonstrates similar stability of an UC insert compared with a standard CR insert. UC inserts are therefore a bone-preserving solution if the PCL needs to be substituted. ROM was not improved after resection of the PCL and substitution with the UC insert.

LEVEL OF EVIDENCE

II.

Placement makes a difference: accuracy of an accelerometer in measuring step number and stair climbing

Accurate and easy-to-use measurement tools are required to evaluate the effect of treatments on patient activity. Comfortable device placement and fixation are important for patient compliance. The aim of this study was the evaluation of the accuracy of an accelerometer at different placements and slow velocities.

METHODS

A total of 43 healthy volunteers were included for a literature-based treadmill protocol using five accelerometer positions; a subset of 18 volunteers performed an extended treadmill protocol with velocities between 0.1 and 2.6m/s and finally stair climbing.

RESULTS

An alternative accelerometer position at the anterolateral aspect of the middle shank did measure steps more accurately than at the manufacturer suggested position, especially during slow velocities. Participants preferred the alternative placement at the shank. The accuracy of different accelerometer positions was excellent at velocities between 1.0 and 2.2m/s. During slow velocities below 1.0m/s steps were recorded less accurately. Accepting an error of five percent, the accelerometer recorded steps accurately from 0.5m/s at the alternative placement and from 0.8m/s at the manufacturer suggested placement. Stair climbing was not recorded accurately by any accelerometer position.

CONCLUSION

For measuring step number during slow velocities, the alternative position should be favoured. Stair climbing was not recorded accurately by any tested placement.