Cycle Sprint Test for the Evaluation of Lower Limb Muscle Power After Total Knee Arthroplasty: A Proof-of-Concept Study.

BACKGROUND: Lower limb muscle power is emerging as an important determinant of patient function after knee injury or surgery. This study tested proof of concept of a cycle sprint test for the evaluation of lower limb muscle power, as an outcome measure for patients having total knee arthroplasty (TKA). METHODS: Thirty-two patients were enrolled, of which 16 completed all follow-ups (3, 6, and 12 months). All patients completed the Oxford Knee Score and Knee Injury and Osteoarthritis Outcome Score questionnaires, a 10-m walk test, and 30-second sit-stand test. A trainer-mounted road cycle fitted with an instrumented crank was used for the cycle sprint test. Maximum muscle power was measured from 3, 10-second maximal efforts. RESULTS: Significant improvements in Oxford Knee Score and Knee Injury and Osteoarthritis Outcome scores relative to baseline were achieved at each follow-up (P < .001), and functional test performance improved significantly at 6 and 12 months (P < .001). Compared with the baseline of 268W, muscle power was significantly lower at 3 months (239W, -13%, P < .05) and significantly higher at 12 months (308W, +12%, P < .05). CONCLUSION: The concept of muscle power measurement using a cycle sprint test before and after TKA has been demonstrated in this study. Identification of individuals with lower limb muscle power deficits after TKA may inform rehabilitation programs and enhance long-term outcomes.

The effect of implant modification: the low contact stress experience.

AIMS: The aim of this study was to conduct the largest low contact stress (LCS) retrieval study to elucidate the failure mechanisms of the Porocoat and Duofix femoral component. The latter design was voluntarily recalled by the manufacturer. MATERIALS AND METHODS: Uncemented LCS explants were divided into three groups: Duofix, Porocoat, and mixed. Demographics, polyethylene wear, tissue ingrowth, and metallurgical analyses were performed. RESULTS: In 104 implants, a decrease in the odds of loosening and an increase in metallosis and tissue staining in the Duofix group relative to Porocoat group was detected (p = 0.028). There was an increased presence of embedded metallic debris in the Duofix group (p < 0.001). Decreased tissue ingrowth was associated with the Duofix surface (p < 0.001). The attached beads had reduced microhardness, indicative of adverse thermal processing, which resulted in bead shedding, particulate debris, and metallosis. CONCLUSION: Hydroxyapatite coating of the LCS femoral component produced unexpected results and led to its recall. The root cause was likely a combination of retained alumina grit and a reduction in bead microhardness (mechanical strength) resulting in increased particle debris, metallosis, and early revision. The Duofix LCS femoral component was not equivalent to the Porocoat version despite its approval through the Food and Drug Administration (FDA) 510(k) equivalance approval process. Regulation of the introduction of modified existing devices needs to be improved and the Duofix LCS should have been considered to be a new device for which equivalence had not been demonstrated at the point of introduction. Cite this article: Bone Joint J 2019;101-B:1248-1255.

Are Psychologic Factors Associated With Shoulder Scores After Rotator Cuff Surgery?

BACKGROUND: Psychologic factors are associated with pain and disability in patients with chronic shoulder pain. Recent research regarding the association of affective psychologic factors (emotions) with patients' pain and disability outcome after surgery disagrees; and the relationship between cognitive psychologic factors (thoughts and beliefs) and outcome after surgery is unknown. QUESTIONS/PURPOSES: (1) Are there identifiable clusters (based on psychologic functioning measures) in patients undergoing shoulder surgery? (2) Is poorer psychologic functioning associated with worse outcome (American Shoulder and Elbow Surgeons [ASES] score) after shoulder surgery? METHODS: This prospective cohort study investigated patients undergoing shoulder surgery for rotator cuff-related shoulder pain or rotator cuff tear by one of six surgeons between January 2014 and July 2015. Inclusion criteria were patients undergoing surgery for rotator cuff repair with or without subacromial decompression and arthroscopic subacromial decompression only. Of 153 patients who were recruited and consented to participate in the study, 16 withdrew before data collection, leaving 137 who underwent surgery and were included in analyses. Of these, 124 (46 of 124 [37%] female; median age, 54 years [range, 21-79 years]) had a complete set of four psychologic measures before surgery: Depression, Anxiety and Stress Scale; Pain Catastrophizing Scale; Pain Self-Efficacy Questionnaire; and Tampa Scale for Kinesiophobia. The existence of clusters of people with different profiles of affective and cognitive factors was investigated using latent class analysis, which grouped people according to their pattern of scores on the four psychologic measures. Resultant clusters were profiled on potential confounding variables. The ASES score was measured before surgery and 3 and 12 months after surgery. Linear mixed models assessed the association between psychologic cluster membership before surgery and trajectories of ASES score over time adjusting for potential confounding variables. RESULTS: Two clusters were identified: one cluster (84 of 124 [68%]) had lower scores indicating better psychologic functioning and a second cluster (40 of 124 [32%]) had higher scores indicating poorer psychologic functioning. Accounting for all variables, the cluster with poorer psychologic functioning was found to be independently associated with worse ASES score at all time points (regression coefficient for ASES: before surgery -9 [95% confidence interval {CI}, -16 to -2], p = 0.011); 3 months after surgery -15 [95% CI, -23 to -8], p < 0.001); and 12 months after surgery -9 [95% CI, -17 to -1], p = 0.023). However, both clusters showed improvement in ASES score from before to 12 months after surgery, and there was no difference in the amount of improvement between clusters (regression coefficient for ASES: cluster with poorer psychologic function 31 [95% CI, 26-36], p < 0.001); cluster with better psychologic function 31 [95% CI, 23-39], p < 0.001). CONCLUSIONS: Patients who scored poorly on a range of psychologic measures before shoulder surgery displayed worse ASES scores at 3 and 12 months after surgery. Screening of psychologic factors before surgery is recommended to identify patients with poor psychologic function. Such patients may warrant additional behavioral or psychologic management before proceeding to surgery. However, further research is needed to determine the optimal management for patients with poorer psychologic function to improve pain and disability levels before and after surgery. LEVEL OF EVIDENCE: Level II, therapeutic study.

Rotator cuff disease: opinion regarding surgical criteria and likely outcome.

BACKGROUND: Clinical guidelines for the management of rotator cuff disease are not clear. Surgeon surveys in the USA and UK lack agreement regarding surgical indications. Physical examination tests aid surgical decision-making but also lack robust evidence. Study aims were to evaluate: Western Australian orthopaedic surgeons' perceptions about surgical indications; utility of physical examination tests; findings at surgery predictive of outcome and surgeon opinion of a successful surgical outcome. METHODS: An anonymous rotator cuff survey, previously reported by the American Academy of Orthopaedic Surgeons, was emailed to all surgeons listed with the Australian Orthopaedic Association in Western Australian. Surgeons who treated patients for rotator cuff disease during the previous 12 months were invited to complete the rotator cuff survey and five additional questions were included to capture the above criteria of interest. RESULTS: Within a close community of surgeons based in Western Australia (n = 23) considerable heterogeneity exists in surgical decision-making criteria. A successful surgical outcome was considered to include reduced pain levels, restoration of movement and function and gains in muscle strength. CONCLUSIONS: Research is required to inform robust clinical practice guidelines for rotator cuff surgery. Identification of prognostic factors for successful surgical outcome is imperative.

Rising trends in surgery for rotator cuff disease in Western Australia.

BACKGROUND: Increasing rates of surgery for rotator cuff disease have been reported in the past decade in a number of countries worldwide. Rising surgery rates do not correspond with equivalent increases in shoulder pain prevalence. The aims of the study were: to investigate trends in population-adjusted surgical rates for rotator cuff disease in Western Australia (WA) from 2001 to 2013; to compare population-adjusted arthroscopic surgical trends between (i) private versus public hospital setting; (ii) sex and (iii) different age groups; and to evaluate rising health care costs associated with arthroscopic surgical rates for rotator cuff disease. METHODS: Numbers and costs for surgical procedures for rotator cuff disease performed in WA were extracted from the WA Department of Health database for the 13-year period, 2001-2013. RESULTS: Rising surgical trends were demonstrated with arthroscopic subacromial decompression (ASAD) and arthroscopic reconstruction showing large proportional increases of 108.7 and 68.4%, respectively. Increasing trends were mostly linear across private and public hospital settings, gender groups and different age groups. The rise in consumer price index-adjusted costs for ASAD in private and public hospitals was 273.7 and 320.8%, respectively, and for arthroscopic reconstruction 220.2 and 472.5%, respectively. CONCLUSION: The substantial increase in arthroscopic surgery rates for rotator cuff disease and associated costs in WA over the period 2001-2013 is in spite of evidence that surgical outcomes are no different to exercise interventions. Conservative treatments should be recommended as an initial treatment choice, to arrest escalating health care costs.

Metallosis following a dual coat porous hydroxyapatite shoulder hemiarthroplasty.

We report a case of metallosis following a shoulder hemiarthroplasty with a humeral component resurfacing shoulder replacement.

Training models for meniscal repairs and small joint arthroscopy.

BACKGROUND: The reduced availability of human cadavers and their associated high costs, coupled with an increasing requirement for meeting continuing professional development targets, has accentuated the need for alternative training models that meet current ethical standards. The aim of this study is to identify suitable substitutes that are accessible and cost effective for use as training models for meniscal repairs and small joint arthroscopy. METHOD: Ovine, bovine and porcine stifles were analysed for comparable anatomy to the human knee, arthroscopic access, arthroscopic view and ease of meniscal repair. RESULTS: The bovine stifle joint was found to be too large and offered limited access due to a large anterior fat pad and thick surrounding soft tissue. The ovine and bovine stifles were both easily available and had comparable anatomy to the human knee. Advantages of the porcine stifle include better availability and easier accessibility, comparable anatomy to the human knee and its relatively larger size that made it easier to arthroscope. CONCLUSION: Porcine stifles are cost effective, accessible, allow for meniscal repair and are suitable for arthroscopic access and view. Our view is that they are an ideal training model for arthroscopic meniscal repair, small joint arthroscopy and anterior cruciate ligament reconstruction.

Use of bovine carpal joints as a training model for cruciate ligament repair.

BACKGROUND: Currently, there is a lack of cheap and effective training models to allow orthopaedic surgery trainees to learn the basics of anterior cruciate ligament reconstruction. The aim of this paper was to investigate the viability of using various animal joints as models for the training of anterior cruciate ligament reconstruction. METHOD: Equine stifles, bovine stifles and carpal joints, sheep stifles and porcine stifles, were sourced from a local abattoir. Each joint was assessed for the following criteria: suitable tendons for harvesting, ease of arthroscopy access, adequacy of arthroscopy view and suitable joint surfaces. Tendon harvesting, preparation, joint arthroscopy and tendon tunnelling were performed on the most suitable joint. RESULTS: Equine, bovine, sheep and porcine stifles were found to be unsuitable. The bovine carpal joint was similar to a human wrist joint with two rows of carpal bones and fused metacarpal bones, but with deeper flexion - similar to a human knee joint. The distal joint space was found to provide a greater range of flexion and space than the narrower proximal joint space. The joint capsule provided sufficient integrity during saline irrigation to allow adequate visualization of joint structures. Tendons surrounding the joint were found to be of similar diameter to human hamstring tendons and easily accessible. Tendon tunnelling was successfully performed in a manner similar to human anterior cruciate ligament repair. CONCLUSION: The use of bovine carpal joints is a cost-effective, safe and easily reproducible model for education on basic anterior cruciate ligament repair skills and technique prior to patient contact.