Calipered kinematic alignment restored the arithmetic hip-knee-ankle angle, achieved high satisfaction and improved clinical outcomes.

PURPOSE: The purpose of this study was to determine whether unrestricted calipered kinematic alignment (KA), coupled with a medial-stabilised (MS) implant system, can reproduce the patient's constitutional alignment as per the arithmetic hip-knee-ankle (aHKA) and improve clinical outcomes. METHODS: One-hundred and ninety-three patients received total knee arthroplasty by the senior author. To determine whether the constitutional alignment was achieved, the postoperative hip-knee-ankle (HKA) alignment was compared against the aHKA. Range of motion (ROM) was determined preoperative and postoperatively at 6 months and 2 years by measuring the active flexion and extension. Patient-Reported Outcomes Measures (PROMs) including Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), Forgotten Joint Score (FJS) and Visual Analogue Scale for Satisfaction were also completed. The Sports and Recreation component of KOOS was used to assess the patient's ability to return to sports and daily activities. RESULTS: There was a strong correlation between postoperative HKA and aHKA (r = 0.7, p < 0.05). There was a significant improvement in both extension and flexion seen from as early as 6 months postoperatively, with a mean flexion of 123° ± 11° and extension of 1° ± 3° at 2 years. PROMs had significant improvements with a mean score of 42.8 ± 6.0 for the OKS and all KOOS subscales consisting of Symptoms (88.0 ± 11.7), Pain (91.4 ± 11.6), Activities of Daily Living (91.1 ± 12.4), Sports (76.8 ± 22.1) and Quality of Life (83.0 ± 19.1). The FJS had significant improvements from 6 months to 2 years of 19.9 (p < 0.05), with a mean score of 69.2 ± 26.6 at 2 years. Ninety-three percent (180 patients) were classified as 'satisfied' at the 2-year timepoint. The KOOS Sports component was completed by 64% (124 patients), whereby the mean age was younger than the noncompliant patients (67.7 ± 9.4 vs. 71.7 ± 8.2 years). CONCLUSION: Unrestricted calipered KA can result in an alignment that closely resembles the patient's constitutional alignment, as per the aHKA. This resulted in improved knee ROM and patient satisfaction, as well as assisting younger patients to return to sports and daily activities. LEVEL OF EVIDENCE: Level IV.

The Early Clinical Outcomes Following Unrestricted Caliper Verified Kinematic Alignment Using a Medial Stabilized Design Total Knee Arthroplasty With a Cruciate Retaining Insert.

Background: Although various total knee arthroplasty (TKA) implant designs are widely used, the ideal TKA design is yet to be agreed upon. Although the benefits of cruciate-retaining (CR) TKA and medial stabilized (MS) TKA have been reported in literature, the early clinical outcomes of an MS TKA with CR inserts have not been reported. This study aims to report on the patient-reported clinical and radiological outcomes of MS-TKA combined with a CR insert. Methods: A prospective single-surgeon series evaluated the clinical- and patient-reported outcomes of 115 patients implanted with GMK Sphere CR. Patient outcomes were assessed with the Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Scores (KOOS), Forgotten Joint Score, and Visual Analogue Scale for Satisfaction. Radiological assessment for alignment along with active flexion and extension were also assessed. Results: Improvement in all scores was observed between the preoperative and 1-year follow-up timepoints, with statistical significance seen for Oxford Knee Score as well as KOOS Symptoms, Pain, Sport, quality of life, and activities of daily living subscales. The mean active flexion between the preoperative and both postoperative timepoints at 6 months and 1 year was also statistically significant (P = .021 and P = .001). Conclusions: MS-TKA with a CR insert can facilitate symptom relief and improve overall function of the knee after surgery. Both the patient and clinical outcomes were comparable to 1-year outcomes utilizing other MS-TKA designs and were superior to those at 1-year follow-up following implantation of CR-TKA. Most notability, the KOOS symptoms and sports score were higher for the MS-TKA with a CR insert than for an MS-TKA design.

The ceiling effects of patient reported outcome measures for total knee arthroplasty.

BACKGROUND: Patient reported outcome measurements (PROMs) that exhibit a substantial ceiling effect show clustering of participant's scores towards the upper limit of a scale and consequently have low discriminatory power among high end scores. This study aimed to compare ceiling effects at 1 and 2 years postoperatively across commonly usedPROMs for TKA. HYPOTHESIS: We hypothesized, that the analyzed PROMs differ substantially in regards to their ceiling effect. PATIENTS AND METHODS: Patients that underwent a primary unilateral TKA and completed pre-operative and post-operative questionnaires were included in the analysis. Participants completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC and OKS preoperatively, and completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC,OKS and FJS postoperatively at 1 and 2 years. RESULTS: 1-year and 2-year follow-up data was available for 380 and 193 patients, respectively. The preoperative mean age was 68.0 (8.5) and mean BMI was 31.4kg/m2 (6.6), with a male to female ratio of 49.6% to 50.4%. At 1 year postoperatively, a ceiling effect was seen for the Pain and ADL subscales of the KOOS and the KOOS JR. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a ceiling effect at 2 years postoperatively. We found 9.0% and 14.8% of patients achieving a maximum score in the FJS at 1 and 2 years, respectively, indicating the absence of a substantial ceiling effect. CONCLUSION: The PROMs studied differ substantially with regards to their ceiling effect and consequently their ability to detect differences between well performing groups. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a substantial ceiling effect at 2 years postoperatively. We recommend using PROMs like the FJS and KOOS-12 with a more evenly distribution of scores across the scale when studying well performing cohorts. LEVEL OF EVIDENCE: III.

The KOOS-12 shortform shows no ceiling effect, good responsiveness and construct validity compared to standard outcome measures after total knee arthroplasty.

PURPOSE: To investigate the validity, responsiveness and ceiling effect of the recently introduced KOOS-12 and compare its performance to the KOOS, OKS, WOMAC and UCLA activity scales. METHODS: Patients from an independent multicentre study examining a medially stabilized knee system prospectively completed the KOOS, OKS, WOMAC and UCLA preoperatively and at 1 year postoperatively. KOOS-12 scores were calculated from the full length KOOS data. Construct validity was assessed using Spearman's correlation analysis. The ceiling effect was evaluated by calculating the percentage of patients with a maximum score. If the percentage exceeded 15%, a ceiling effect was considered to be present. Responsiveness was evaluated by performing paired t tests on the changes in measures and calculation of Cohen's d. RESULTS: A ceiling effect was present for the KOOS Pain, ADL and QoL subscales and the KOOS-JR at 1 year postoperatively. No ceiling effect was observed for the KOOS-12. Correlation of the KOOS-12 was low (0.3 < r < 0.5) with the UCLA, moderate (0.5 < r < 0.7) with the KOOS symptoms, sports and WOMAC stiffness subscales and high (r > 0.7) with all other scores and subscales. Effect size of the UCLA activity scale was moderate (Cohen's d 0.2-0.8) whereas effect sizes of all other outcome measures were large (d > 0.8). CONCLUSION: The KOOS-12 does not exhibit a ceiling effect, has good convergent construct validity and is responsive to changes in pain, function, QoL and knee impact between preoperatively and 1 year postoperatively. LEVEL OF EVIDENCE: Diagnostic level III.

The surgical repair of proximal hamstring avulsions.

AIMS: Despite the increase in the surgical repair of proximal hamstring tears, there exists a lack of consensus in the optimal timing for surgery. There is also disagreement on how partial tears managed surgically compare with complete tears repaired surgically. This study aims to compare the mid-term functional outcomes in, and operating time required for, complete and partial proximal hamstring avulsions, that are repaired both acutely and chronically. METHODS: This is a prospective series of 156 proximal hamstring surgical repairs, with a mean age of 48.9 years (21.5 to 78). Functional outcomes were assessed preinjury, preoperatively, and postoperatively (six months and minimum three years) using the Sydney Hamstring Origin Rupture Evaluation (SHORE) score. Operating time was recorded for every patient. RESULTS: Overall, significant improvements in SHORE scores were seen at both six months and mid-term follow-up. Preoperatively, acute patients (median score 27.1 (interquartile range (IQR) 22.9)) reported significantly poorer SHORE scores than chronic patients (median score 42.9 (IQR 22.1); p < 0.001). However, this difference was not maintained postoperatively. For partial tears, acutely repaired patients reported significantly lower preoperative SHORE scores compared to chronically reapired partial tears (median score 24.3 (IQR 15.7) vs median score 40.0 (IQR 25.0); p < 0.001) but also significantly higher SHORE scores at six-month follow-up compared to chronically repaired partial tears (median score 92.9 (IQR 10.7) vs. median score 82.9 (IQR 14.3); p < 0.001). For complete tears, there was only a difference in preoperative SHORE scores between acute and chronic groups. Overall, acute repairs had a significantly shorter operating time (mean 64.67 minutes (standard deviation (SD) 12.99)) compared to chronic repairs (mean 74.71 minutes (SD = 12.0); t = 5.12, p < 0.001). CONCLUSION: Surgical repair of proximal hamstring avulsions successfully improves patient reported functional outcomes in the majority of patients, irrespective of the timing of their surgery or injury classification. However, reducing the time from injury to surgery is associated with greater improvement in patient outcomes and an increased likelihood of returning to preinjury functional status. Acute repair appears to be a technically less complex procedure, as indicated by reduced operating times, postoperative neurological symptoms and number of patients requiring bracing. Acute repair is therefore a preference among many surgeons. Cite this article: Bone Joint J 2020;102-B(10):1419-1427.

Validation of the Sydney Hamstring Origin Rupture Evaluation (SHORE).

AIMS: To validate the Sydney Hamstring Origin Rupture Evaluation (SHORE), a hamstring-specific clinical assessment tool to evaluate patient outcomes following surgical treatment. METHODS: A prospective study of 70 unilateral hamstring surgical repairs, with a mean age of 47.3 years (15 to 73). Patients completed the SHORE preoperatively and at six months post-surgery, and then completed both the SHORE and Perth Hamstring Assessment Tool (PHAT) at three years post-surgery. The SHORE questionnaire was validated through the evaluation of its psychometric properties, including; internal consistency, reproducibility, reliability, sensitivity to change, and ceiling effect. Construct validity was assessed using Pearson's correlation analysis to examine the strength of association between the SHORE and the PHAT. RESULTS: The SHORE demonstrated an excellent completion rate (100%), high internal consistency (Cronbach's alpha 0.78), and good reproducibility (intraclass correlation coefficient (ICC) 0.82). The SHORE had a high correlation with the validated PHAT score. It was more sensitive in detecting clinical change compared to the PHAT. A ceiling effect was not present in the SHORE at six months; however, a ceiling effect was identified in both scores at three years post-surgery. CONCLUSION: This study has validated the SHORE patient reported outcome measure (PROM) as a short, practical, reliable, valid, and responsive tool that can be used to assess symptom and function following hamstring injury and surgical repair. Cite this article: Bone Joint J 2020;102-B(3):388-393.

Review on squeaking hips.

Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4(th) generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking.

Two-year serum metal ion levels in minimally invasive total conservative hip resurfacing: preliminary results of a prospective study.

BACKGROUND: Metal-on-metal (MoM) hip resurfacings have been associated with the potential development of metallic debris and its associated pathology. Serum cobalt and chromium levels are a reliable surrogate marker of wear rates in MoM bearings. The aim of the study was to examine the trend in serum metal ion levels in the initial 2-year post-operative period following implantation of the minimally invasive total conservative hip MoM hip resurfacing and to determine whether head size, acetabular component orientation, clinical outcome scores or post-operative range of movement would affect these levels. METHODS: In this prospective cohort study, serum cobalt and chromium ion levels were measured pre- and post-operatively in 25 patients who underwent minimally invasive total conservative hip MoM hip resurfacing. The results were correlated with acetabular component orientation, head size, outcome scores and post-operative range of movement. RESULTS: The mean serum cobalt and chromium levels at 2 years were 1.2 ppb (0.4-4.4 ppb) and 2.1 ppb (0.7-5.7 ppb). The mean cup inclination was 43° (30°-60°) and anteversion was 18° (1°-47°). There was no clear relationship between serum ions and acetabular component orientation, outcome scores or range of movement. Patients with a head size ≤52 mm had significantly higher metal ion levels (cobalt P = 0.02, chromium P = 0.045). CONCLUSION: Our preliminary results show all patients had cobalt and chromium levels below those indicating a high-risk implant, suggesting successful early outcome from minimally invasive total conservative hip resurfacing surgery.

Variations in the trunnion surface topography between different commercially available hip replacement stems.

Modular hip implants allows for the adjustment of leg length, offset, and the ability to remove the head for acetabular exposure during primary and revision surgery. The design of the Morse taper facilitates the intimate contact of the conical trunnion of the femoral stem (male component), with the conical bore of the femoral head (female component). Orthopaedic trunnion tapers are not standardized and vary in length, taper angle, and base dimension. Variations in the design and surface characteristics of the trunnion, will directly reflect on the interface at the taper junction and can influence the likelihood of subsequent wear, corrosion and longevity of the implant. The effect of surface topography of trunnions on commercially available hip stems has not yet been considered as a possible contributing factor in the corrosion observed at taper junctions. In this study we analyzed the surface topography and surface roughness of randomly selected commercially available femoral hip stem trunnions to obtain a greater insight into their surface characteristics.

Squeaking in large diameter ceramic-on-ceramic bearings in total hip arthroplasty.

We analyzed the results of 206 consecutive total hip arthroplasties performed using large diameter ceramic-on-ceramic bearings. At an average follow-up of 28months, the mean Harris Hip Score improved from 54 to 92. Fifteen (7.3%) hips were noted to squeak. There was no significant difference between silent and squeaking hips with regards to age, weight, height, BMI, range of movement, femoral head diameter, leg length, and offset or center of rotation. No correlation was present between incidence of squeaking and increasing cup inclination and anteversion. 5.2% of cups orientated within Lewinnek's safe zone squeaked. No hips required revision for squeaking. While large diameter ceramic bearings may produce squeaking, our early results of surgery using large head ceramic bearings are encouraging. However, long-term follow-up is required.

The effect of obesity on the clinical, functional and radiological outcome of cementless total hip replacement: a case-matched study with a minimum 10-year follow-up.

1420 primary cementless THRs with a minimum follow-up of 10-years were stratified according to BMI: non-obese (BMI<30kg/m(2)) and obese (BMI≥30kg/m(2)). Median age at surgery was younger in obese patients (P<0.001). We case-matched 82 THRs in obese patients with 162 THRs in non-obese patients. No difference between groups was found in improvement in HHS (P=0.668), satisfaction with surgery (P=0.644), range of movement, prosthesis orientation, or radiological loosening. The obese cohort was further separated into those with a BMI below and above 35. No difference was found between groups in improvement in HHS, satisfaction with surgery, component orientation, or radiological loosening. There was no difference in the incidence of post-operative complications between obese and non-obese patients. After 10-years, the results of THR are not compromised by obesity.

Factors affecting squeaking in metal on metal hip resurfacings.

We reviewed 380 hip resurfacings cases between December 1999 and Dec 2012. 11 cases (2.89%) squeaked postoperatively. Mean follow-up was 88.6 months (19-130 months). Mean time to squeak was 11.3 months (3-22 months). Ten (91%) cases were male and nine (81%) cases had a Birmingham hip resurfacing. Cases were matched for age, gender, BMI and implant to three controls. Radiographs were analysed using EBRA (Einzel-Bild-Roentgen-Analysis, University of Innsbruck, Austria) software to evaluate cup orientation. There was no significant difference between the mean inclination angle of the cups (p = 0.26) or the mean anteversion angle (p = 0.29). There was no difference in serum cobalt (p = 0.20) or serum chromium (p = 0.45) levels at latest follow-up. Three of the 11 (27.3%) cases had revision surgery at a mean follow-up of 101 months (72-117 months). Squeaking was not influenced by patient demographic parameters and resolved in all cases that did not undergo revision surgery. Males with a resurfacing head size <50 mm had significantly increased odds of squeaking when compared to controls (odds ratio = 26.6; 95% CI = 1.2-573.3; p<0.05). Based on our findings, we do not recommend that squeaking on its own should be an indication for revision of hip resurfacing components.

Fretting and corrosion in modular-neck total hip arthroplasty femoral stems.

BACKGROUND: During total hip arthroplasty, use of a modular femoral neck on a stemmed implant allows optimization of neck anteversion, length, and offset, resulting in more accurate balance. We performed a retrospective analysis of a consecutive cohort of patients who had undergone total hip arthroplasty with a modular-neck hip system with ceramic-on-ceramic bearings. METHODS: We reviewed the results in fifteen patients who had received an ABG II dual modular hip system (Stryker Orthopaedics, Mahwah, New Jersey) from May 2007 to August 2008. Anteroposterior radiographs of the pelvis were reviewed and scored with regard to medial calcar erosion. Magnetic resonance imaging (MRI) was performed to assess for adverse local tissue reaction around the hip joint. Calcar resorption was correlated with subsequent MRI findings. Retrieval analysis was performed on the implants removed at revision. RESULTS: The mean duration of follow-up for all patients was 42.3 months (range, thirty-three to sixty months). Cobalt-ion levels were elevated in all patients; chromium levels were within the normal range. Medial femoral calcar erosion was noted in seven of the fifteen cases. All patients with grade-2 or 3 calcar erosion on radiographs had positive MRI findings consistent with adverse local tissue reaction. At the time of writing, seven patients had undergone revision arthroplasty. Intraoperatively, tissue staining with tissue and bone necrosis and pseudotumor formation were observed in all revision cases. Histological analysis confirmed the presence of metal-on-metal synovitis, with changes similar to those seen with metal-on-metal bearings. CONCLUSIONS: The ABG II dual modular hip system is associated with a high rate of early failure secondary to fretting and corrosion at the femoral neck-stem taper. The component has subsequently been recalled and is no longer in use. Surgeons using modular hip systems with a titanium stem and cobalt-chromium neck should be vigilant about annual follow-up with radiographs, and use of MRIs as indicated.