Observational Study of Total Knee Arthroplasty in Aseptic Revision Surgery: Clinical Results

A Newly Designed "SkyWalker" Robot Applied in Total Knee Arthroplasty: A Retrospective Cohort Study for Femoral Rotational Alignment Restoration

Objective

This study explored whether robotic arm‐assisted total knee arthroplasty (RATKA) has the advantage of restoring femoral rotational alignment compared to conventional total knee arthroplasty (COTKA).

Methods

Sixty patients (45 women and 15 men) attending our department from May 2019 to December 2020 were selected and divided into two groups, with 30 patients in each group, according to whether they underwent COTKA or RATKA. Femoral rotational alignment results, such as, posterior condylar angle (PCA), patella transverse axis‐femoral transepicondylar axis angle (PFA), radiological findings, such as, hip‐knee‐ankle angle (HKA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA), and operative data (operation time, intraoperative blood loss, tourniquet time, and length of stay (LOS), and clinical outcomes, such as maximum knee flexion angle (MKFA), Knee Society Score (KSS), and Western Ontario Mac Master University Index Score (WOMAC) were compared within and between the two groups.

Results

PCA and PFA in the RATKA group were (0.6 ± 0.3)° and (0.9 ± 0.3)°, respectively, which were smaller than (1.5 ± 2.0)° and (3.1 ± 1.1)° in the COTKA group (P < 0.05), and were closer to 0°; the differences in HKA, LDFA, and MPTA were not statistically significant. With the exception of the LDFA, the HKA, MPTA, PCA, and PFA improved in both groups after surgery (P < 0.05). The blood loss and the LOS of RATKA group were 192.3 ± 23.1 mL and 8.2 ± 1.4 days, which were less than 203.7 ± 29.8 mL and 9.3 ± 1.1 days of the COTKA group, but the operation time showed no statistically significant difference, and the tourniquet time was longer (P < 0.05). The MKFA in the RATKA group was (123.0 ± 3.7)°, which was greater than (116.3 ± 4.6)° in the COTKA group (P < 0.05). In terms of scores, the postoperative results were better than the preoperative results in both groups (P < 0.05). However, there was no statistically significant difference between the groups.

Conclusion

The accuracy of femoral rotational alignment reconstructed achieved by RATKA is significantly better than that of COTKA and is more conducive to the recovery of knee flexion function after surgery; although RATKA reduces intraoperative blood loss and postoperative LOS, the short‐term clinical efficacy comparison has not yet demonstrated the advantages of robotic technology, and a more optimized design is needed to improve the efficiency of RATKA surgery.

Patient-reported outcome measures following revision knee replacement: a review of PROM instrument utilisation and measurement properties using the COSMIN checklist

OBJECTIVES

To identify: (1) patient-reported outcome measures (PROMs) used to evaluate symptoms, health status or quality of life following discretionary revision (or re-revision) knee joint replacement, and (2) validated joint-specific PROMs, their measurement properties and quality of evidence.

DESIGN

(1) Scoping review; (2) systematic review following the COnsensus-based Standards for selection of health status Measurement INstruments (COSMIN) checklist.

DATA SOURCES

MEDLINE, Embase, AMED and PsycINFO were searched from inception to 1 July 2020 using the Oxford PROM filter unlimited by publication date or language.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies reporting on the development, validation or outcome of a joint-specific PROM for revision knee joint replacement were included.

RESULTS

51 studies reported PROM outcomes using eight joint-specific PROMs. 27 out of 51 studies (52.9%) were published within the last 5 years. PROM development was rated 'inadequate' for each of the eight PROMs studied. Validation studies were available for only three joint-specific PROMs: Knee Injury and Osteoarthritis Outcome Score (KOOS), Lower Extremity Activity Scale (LEAS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC). 25 out of 27 (92.6%) measurement properties were rated insufficient, indeterminate or not assessed. The quality of supporting evidence was mostly low or very low. Each of the validated PROMs was rated 'B' (potential for recommendation but require further evaluation).

CONCLUSION

Joint-specific PROMs are increasingly used to report outcomes following revision knee joint replacement, but these instruments have insufficient evidence for their validity. Future research should be directed toward understanding the measurement properties of these instruments in order to inform clinical trials and observational studies evaluating the outcomes from joint-specific PROMs.

Isolated Partial Femoral Avulsion Fracture of the Posterior Cruciate Ligament in Adults

Objective

To investigate the manifestation, mechanisms, and treatment of isolated partial femoral avulsion fractures of the posterior cruciate ligament (PCL) in adults.

Methods

From January 2011 to December 2018, we retrospectively reviewed the clinical data of three patients with isolated partial femoral avulsion fractures of the PCL who were admitted to our institution. All of these patients were admitted to our emergency department within 24 h after injury. After physical examination and radiographs were taken and reviewed, all patients were admitted and underwent surgical treatment. In a 26‐year‐old man who underwent arthroscopic surgery through the traditional medial and lateral approach before finally converting to open surgery with the posterior approach, the fragment that was finally removed was partially attached to the PCL. In the other two patients, women aged 63 and 68 years, who underwent arthroscopic surgery via the traditional medial and lateral approach, the fragments were large and attached to most fibers of the PCL. We fixed the fragments using hollow screws in arthroscopic view. In addition, in the 63‐year‐old patient, an anchor was embedded to restore the tension of the PCL. Four weeks after surgery, the patients started to wear long leg braces in full extension with the tibia blocked up by cushion. Physical examinations were conducted and radiographs were taken preoperatively and at 4 weeks and 3 months after surgery to evaluate the condition of the injury. The range of motion and the Lysholm knee scoring scale for the knee joint were compared before and after the surgery.

Results

For the three patients, the radiographs taken at 3 months postoperatively showed that the fixation of the screws did not fail, and the subchondral bone was generally normal compared to the preoperative radiographs. CT scanning at 3 months after surgery showed that the fracture healed in the original position of the avulsion site. For all patients, the affected knees presented as stable at physical examination 3 months after surgery; the Lachmann test and the anterior drawer test results were negative. In addition, the flexion–extension, internal rotation, and external rotation were approximately 0°–130°, 0°–30°, and 0°–40° in the 26‐year‐old patient, respectively. The flexion–extension, internal rotation, and external rotation were approximately 0°–100°, 0°–20°, and 0°–35° for the 63‐year‐old patient, respectively. The flexion–extension, internal rotation, and external rotation were approximately 0°–100°, 0°–15°, and 0°–20° for the 68‐year‐old patient, respectively. There was no pain or only little pain 3 months after surgery. There was no swelling or discomfort at the 3‐month follow up. The Lysholm knee scores of the 68‐year‐old, 63‐year‐old, and 26‐year‐old patient were 80, 87, and 95 at 3 months after surgery, respectively, which were obviously improved postoperatively.

Conclusion

The manifestation of isolated partial femoral avulsion fractures of the PCL in adults is often related to the injury mechanism, and surgery is essential for the treatment of these patients. Most of these fractures can be repaired by arthroscopic surgery, but some have to be treated by open surgery.

Personality Traits Affect the Cost-Effectiveness of Total Knee Arthroplasty

Objective

To assess the clinical benefit and compare the cost‐effectiveness of total knee arthroplasty (TKA) in patients with different personality traits.

Methods

The present study was retrospectively conducted from January 2017 to May 2018. A total of 232 patients between 46 and 71 years old who underwent unilateral, primary TKA with the diagnosis of knee osteoarthritis were interviewed. Three types of data were required to compare the cost‐effectiveness differences among groups: personality traits, postoperative clinical outcomes about health‐related quality of life, and costs associated with TKA. Personality was assessed using the Eysenck Personality Questionnaire, functional outcome was assessed through the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, and costs were evaluated. Besides, the marginal cost‐effectiveness ratio (MCER) as the primary outcome, which relates the direct costs to the associated patient benefit as assessed by the clinical endpoint ($/quality‐adjusted life years [QALY]), was compared among different personality traits. All information for this study was acquired by directly interviewing the patients and reviewing the medical computer records at our hospital.

Results

Two hundred and eleven patients completed the final analysis with an average of 24.6 months follow‐up postoperatively. The choleric group, sanguine group, melancholic group, and phlegmatic group has 41, 70, 46, and 54 patients, respectively. A statistically significant difference in MECR, QALYs, and postoperative WOMAC existed among different personality traits (all P < 0.05). There was no significant difference in mean age (P = 0.588), body mass index (BMI) (P = 0.790), smoking (P = 0.934), heavy drinking (P = 0.994), chronic comorbidities (all P > 0.05), preoperative albumin <3.5 g/dL (P = 0.991), and American Society of Anaesthesiologists (ASA) score (P = 0.687) among personality traits. More women tend to be melancholic in comparison to other personality traits (P = 0.016). Melancholic patients attested inferiority of TKA compared with other personality traits, who would pay for the same QALYs at the highest costs (P < 0.05). By contrast, sanguine patients have a more cost‐effective TKA than other personality traits, as they pay the least money for the same QALYs (P < 0.05). Although phlegmatic and choleric patients seemingly have moderate gains from TKA, in general, the extroversion (measured by the extroversion subscale) and stability (measured by the neuroticism subscale) displayed more pleasurable QALYs in comparison with introversion and instability (P < 0.05). Sensitivity analysis showed that the results mentioned above appeared not to be sensitive when varying key parameters (prosthesis survival and life expectancy) in a one‐way sensitivity analysis. Sanguine and melancholic patients still have the lowest and highest MCER in comparison with choleric and phlegmatic traits (P < 0.05). The multivariate logistic regression showed that RA (adjusted OR = 1.3, 95% CI = 1.2–1.4, P < 0.01), ASA Class I–II (adjusted OR = 0.9, 95% CI = 0.8–1.0, P < 0.001), sanguine (adjusted OR = 0.8, 95% CI = 0.7–0.9, P < 0.001) and melancholic (adjusted OR = 1.2, 95% CI = 1.1–1.3, P < 0.001) were significantly associated with MCER.

Conclusions

Before surgery, screening the melancholic patients would significantly reduce the economic burden, avoid unnecessary suffering, and shorten the recovery period.

Early Failures of Total Knee Patients with Nickel Allergies Secondary to Carbon Fiber Debris

Aim:

Currently, there are not many studies on the long-term outcomes of the specific implants used in patients with metal hypersensitivities. The purpose of this study is to report a significant number of TKA revision failures with the CFR-PEEK prosthetic knee implant with an anatomic hinge.

Background:

Patients can experience multiple issues following a primary Total Knee Arthroplasty (TKA). A growing body of research is finding a correlation between primary TKA failure and metal hypersensitivity, most commonly with nickel and cobalt. Because of this, knee prosthetics are being made from hypoallergenic metals, such as zirconium nitride (ZrN), to minimize the number of failures due to metal allergy. Given the relatively new development of the hypoallergenic prostheses, there is sparse data about their overall success.

Objective:

The purpose of this study is to report a significant number of TKA revision failures with the CFR-PEEK prosthetic knee implant with an anatomic hinge.

Methods:

In this study, we analyzed the sequelae of 84 patients between May 2015 to June 2020 who received a total knee revision due to a failed primary TKA with metal hypersensitivity. These patients were revised with the rotating anatomic hinge knee system, which consisted of Carbon Fiber Reinforced Poly-Ether-Ether-Ketone (CFR-PEEK implant) coated with a ZrN, Zirconium, and Chrome Nitride multi-layer surface coating with 30% polyacrylonitrile fiber content. The patients requiring an additional revision operation presented with increasing pain that showed evidence of osteolysis on plain radiographs, CT imaging, positive indium labeled WBC scans and increased uptake on bone scan. Intraoperatively, an open incisional biopsy of the surgical bed was obtained, followed by radical debridement and implantation of porex knee prosthesis. In addition, intraoperative findings included black debris that grossly stained the surrounding synovial tissue black, indicative of wear and debris from carbon fiber bearings and the anatomic hinge. Histology of the intraoperative biopsy showed the accumulation of black debris in the histiocyte, fibrosis, and perivascular cuffing of lymphocytes and multinucleated giant cells stained with black debris.

Results:

Of the 84 patients, 22 failed, requiring an additional revision procedure, equating to a 26 percent failure rate of the CFR-PEEK implant, averaging 25 months to failure.

Conclusion:

This study was meant to report the extremely high failure rate of the anatomic hinge secondary to carbon fiber debris. Perhaps carbon fiber-laden implants are not as good an option for total knee revision prosthesis because of the high failure rate compared to those with polyethylene in their hinge mechanism.