Minimum 5-Year Outcomes of a Multicenter, Prospective, Randomized Control Trial Assessing Clinical and Radiological Outcomes of Patient-Specific Instrumentation in Total Knee Arthroplasty.

BACKGROUND: Patient-specific instrumentation (PSI) was developed to produce more accurate alignment of components and consequently improve clinical outcomes when used in total knee arthroplasty. We compare radiological accuracy and clinical outcomes at a minimum of 5-year follow-up between patients randomized to undergo total knee arthroplasty performed using PSI or traditional cutting block techniques. METHODS: This multicenter, randomized control trial included patients blinded to the technique 1used. Outcome measures were coronal alignment measured radiologically, Euroqol-5D, Oxford knee score, and International Knee Society Score measured at 1- and 5-year follow-up. RESULTS: At a minimum 5-year follow-up, there were 38 knees in the PSI group and 39 in the conventional instrumentation group for analysis. Baseline demographics and clinical outcome scores were matched between groups. Overall, there was no significant difference in the coronal femoral angle (P = .59), coronal tibial angle (P = .37), tibiofemoral angle (P = .99), sagittal femoral angle (P = .34), or the posterior tibia slope (P = .12) between knees implanted using PSI and those implanted with traditional cutting blocks. On the measurement of coronal alignment, intraobserver reliability tests demonstrated substantial agreement (k = 0.64). Clinical outcomes at both 1-year and 5-year follow-up demonstrated statistically significant and clinically relevant improvement in scores from baseline in both groups, but no difference could be detected between the Euroqol-5D (P = .78), Oxford knee score (P = .24), or International Knee Society Score (P = .86) between the 2 groups. CONCLUSION: This study has shown no additional benefit to PSI in terms of improved alignment or functional outcomes at minimum 5-year follow-up over traditional techniques.

Radiofrequency Microdebridement as an Adjunct to Arthroscopic Surgical Treatment for Recalcitrant Gluteal Tendinopathy: A Double-Blind, Randomized Controlled Trial.

BACKGROUND: Recalcitrant greater trochanteric pain is increasingly recognized as an indication for surgical intervention. The arthroscopic approach has become rapidly more common than the open alternative. HYPOTHESIS: Patients undergoing radiofrequency microdebridement (RFMD) as an adjunct to arthroscopic gluteal bursectomy (AGB) and iliotibial band release (ITBR) will experience better functional improvement than AGB and ITBR alone at 1 year. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: A total of 33 patients with failed nonoperative treatment of gluteal tendinopathy were randomly allocated to undergo AGB/ITBR or AGB/ITBR + RFMD. Full-thickness tears were excluded. The primary outcome measure was the modified Harris Hip Score (mHHS) at 52 weeks. Secondary outcome measures included the mHHS, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain, and 12-item Short Form Health Survey (SF-12), which were evaluated at 0, 6, 12, 24, and 52 weeks. Statistical significance was defined as P < .05. RESULTS: A total of 33 participants (33 hips; 30 female and 3 male; mean age, 58 years) were randomized; 16 patients underwent AGB/ITBR + RFMD, and 17 underwent AGB/ITBR. Participants' functionality improved in both groups at all time intervals. The mean mHHS score improved from 57.49 ± 10.61 to 77.76 ± 18.40 (P = .004) and from 58.98 ± 12.33 to 79.96 ± 18.86 (P = .001) at 52 weeks in the AGB/ITBR and AGB/ITBR + RFMD groups, respectively, although there was no statistically significant difference between groups. There were no device-related adverse events. CONCLUSION: AGB/ITBR led to significant improvements in patients with recalcitrant gluteal tendinopathy. In this small RCT, the addition of RFMD showed no additional benefit to AGB/ITBR but provided a safe adjunct for the surgical management of recalcitrant gluteal tendinopathy. REGISTRATION: NCT01562366 (ClinicalTrials.gov identifier).

A biomechanical study comparing two fixation methods in depression fractures of the lateral tibial plateau in porcine bone.

BACKGROUND: A novel method of fixation has been described for the treatment of pure depression fractures of the lateral tibial plateau. Fracture fragments are elevated through a reamed transtibial tunnel. An interference screw is then passed into the tunnel to buttress fracture fragments from beneath. This method of fixation has perceived benefits but there have been no studies to demonstrate that the technique is biomechanically sound. The aim of our study is to compare traditional parallel, subchondral screw fixation with the use of an interference screw, assessing maintenance of fracture reduction following simulated post-operative loading, and overall construct strength. METHODS: Depression fractures of the lateral tibial plateau were simulated in 14 porcine knees. Fracture fragments were elevated through a reamed transtibial tunnel and samples were randomly assigned to a fixation method. 7 knees underwent traditional fixation with parallel subcortical cannulated screws, the remainder were stabilized using a single interference screw passed through the transtibial tunnel. Following preloading, each tibia was cyclically loaded from 0 to 500 Newtons for 5,000 cycles using a Nene testing machine. Displacement of the depressed fracture fragments were measured pre and post loading. Samples were then loaded to failure to test ultimate strength of each construct. RESULTS: The depression displacement of the fractures fixed using cannulated screws was on average 0.76 mm, in comparison to 0.61mm in the interference screw group (p=0.514). Mechanical failure of the cannulated screw constructs occurred at a mean of 3400 N. Failure of the transtibial interference screw constructs occurred at a mean of 1700 N (p<0.01). In both groups the mechanism of ultimate failure was splitting of the tibial plateau. CONCLUSION: These results demonstrate the increased biomechanical strength of parallel, cannulated screws for depression fractures of the tibial plateau, however the use of a transtibial interference screw may be a viable method of fixation under physiological loads.

Failure of cement-in-shell acetabular liner exchange.

Cement-in-shell acetabular liner exchange is a revision surgery option for cases of total hip arthroplasty (THA) with polyethylene wear where direct liner exchange is not possible. A replacement liner is cemented into a well fixed uncemented acetabular shell, avoiding the morbidity associated with acetabular shell component revision. We present a case of dissociation of an acetabular liner at the cement-liner interface, three years following liner exchange without radiographic evidence to indicate the diagnosis.

Secondary capsular laxity of the hip.

We describe a hip condition with a recognisable pattern of clinical signs and radiological findings thought to result from chronic capsular injury. Between June 2006 and October 2009, ten patients (11 hips), four men and six women, were identified with an abnormality of external rotation at the hip joint. A detailed history and clinical examination was undertaken for each patient. Dynamic magnetic resonance imaging of symptomatic and control hips were evaluated for bony and soft tissue appearances. The relative positions of the femoral head and the acetabulum were assessed through a range of hip rotation. In affected hips, a loss of normal log roll recoil was observed. Three distortions of the iliofemoral ligament were identified on axial MR images; thinning at the lateral insertion of the ligament, attenuation of the iliofemoral ligament most noticeably on maximum external rotation (60º) and the appearance of laxity despite full external rotation. Stability of the hip is dependent on the interaction of bony and soft tissue structures. Hip instability is recognised in dysplasia and is known to lead to premature degeneration of the joint. Chronic capsular injury may destabilise previously asymptomatic hips with subsequent development of pain in young, active patients.