The BioPoly Partial Resurfacing Knee Implant Provides Beneficial Clinical Outcomes: A Concise Follow-up, at 5 Years, of a Previous Report.

Abstract: We previously conducted a single-arm, prospective study in which 31 patients (mean age [and standard deviation], 42.5 ± 11.3 years) with cartilage lesions were treated with use of the BioPoly Partial Resurfacing Knee Implant. Treatment outcomes were compared with those reported for the standard of care, microfracture. We found that the mean KOOS (Knee injury and Osteoarthritis Outcome Score) Quality of Life score at 5 years in the BioPoly cohort was noninferior to (p = 0.004), and indeed greater than (p = 0.021), that in the microfracture cohort. The BioPoly cohort demonstrated improvement in the mean scores for all KOOS domains at every postoperative time point (p < 0.025). The mean score for the visual analog scale (VAS) for pain significantly improved (p < 0.025) at all time points up to 4 years and trended toward significant improvement at 5 years (p = 0.027). This study indicated that the BioPoly implant was safe, provided significant improvement starting at 6 months and continuing to 5 years, and provided greater improvement than microfracture for some outcome measures. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Outcomes of Hip and Knee Fungal Periprosthetic Joint Infections: A Retrospective Cohort Study.

BACKGROUND: Fungal infections are a rare cause of periprosthetic joint infection (PJI), identified in 1% of all of these cases. Outcomes are not well-established due to small cohort sizes in the published literature. The aims of this study were to establish the patient demographics and infection-free survival of patients presenting to 2 high-volume revision arthroplasty centers who had fungal infection of either a hip or knee arthroplasty. We sought to identify risk factors for poor outcomes. METHODS: A retrospective analysis was performed of patients at 2 high-volume revision arthroplasty centers who had confirmed fungal PJI of the total hip arthroplasty (THA) and total knee arthroplasty (TKA). Consecutive patients treated between 2010 and 2019 were included. Patient outcomes were classified as infection eradication or persistence. A total of 67 patients who had 69 fungal PJI cases were identified. There were 47 cases involving the knee and 22 of the hip. Mean age at presentation was 68 years (THA mean 67, range 46 to 86) (TKA mean 69, range, 45 to 88). A history of sinus or open wound was present in 60 cases (89%) (THA 21 cases, TKA 39 cases). The median number of operations prior to the procedure at which fungal PJI was identified was 4 (range, 0 to 9), THA 5 (range, 3 to 9), and TKA 3 (range, 0 to 9). RESULTS: At a mean follow-up 34 months (range, 2 to 121), remission rates were 11 of 24 (45%) and 22 of 45 (49%) for hip and knee, respectively. There were 7 TKA (16%) and 1 THA cases (4%) that failed treatment resulting in amputations. During the study period, 7 THA and 6 TKA patients had died. Two deaths were directly attributable to PJI. Patient outcome was not associated with the number of prior procedures, patient comorbidities, or organisms. CONCLUSION: Eradication of fungal PJI is achieved in less than half of patients, and outcomes are comparable for TKA and THA. The majority of patients who have fungal PJI present with an open wound or sinus. No factors were identified that increase the risk of persistent infection. Patients who have fungal PJI should be informed of the poor outcomes.

Same Day Biopsy and Treatment of Non-Melanoma Skin Cancer in Patients with Field Cancerization: A Retrospective Chart Study.

Background: Patients with field cancerization will develop numerous superficial non-melanoma skin cancers (NMSCs). Treating patients with field cancerization can be challenging and burdensome due to the numerous non-melanoma skin cancers (NMSCs) they develop and the frequent dermatology visits required for biopsy and treatment. Objective: The success rate of diagnosing and treating lesions suspicious for NMSCs on the same day is measured, immediately after biopsy. Methods: We retrospectively reviewed records of patients with same day lesion diagnosis and curettage treatment to determine diagnostic accuracy, treatment failure, and number needed to treat to reduce a follow-up treatment. Results: A total of 237 lesions underwent same day biopsy and treatment, of which the majority were NMSC (66%) or actinic keratosis (23%). Patients had at least 3 months and a median of 17 months follow-up. A total of 20 lesions either recurred or were deemed to require additional treatment. The number needed to treat (NNT) to prevent one follow-up treatment was 1.3. Limitations: sample size limited ability to determine risk factors for treatment failure. Conclusion: Simultaneous diagnosis and treatment of superficial NMSCs is a successful way of improving efficiency and patient satisfaction.

Ischial screw fixation can prevent cup migration in 3D-printed custom acetabular components for complex hip reconstruction.

INTRODUCTION: Custom acetabular components have become an established method of treating massive acetabular bone defects in hip arthroplasty. Complication rates, however, remain high and migration of the cup is still reported. Ischial screw fixation (IF) has been demonstrated to improve mechanical stability for non-custom, revision arthroplasty cup fixation. We hypothesize that ischial fixation through the flange of a custom acetabular component aids in anti-rotational stability and prevention of cup migration. METHODS: Electronic patient records were used to identify a consecutive series of 49 custom implants in 46 patients from 2016 to 2022 in a unit specializing in complex joint reconstruction. IF was defined as a minimum of one screw inserted into the ischium passing through a hole in a flange on the custom cup. The mean follow-up time was 30 months. IF was used in 36 cups. There was no IF in 13 cups. No difference was found between groups in age (68.9 vs. 66.3, P = 0.48), BMI (32.3 vs. 28.2, P = 0.11) or number of consecutively implanted cups (3.2 vs. 3.6, P = 0.43). Aseptic loosening with massive bone loss was the primary indication for revision. There existed no difference in Paprosky grade between the groups (P = 0.1). 14.2% of hips underwent revision and 22.4% had at least one dislocation event. RESULTS: No ischial fixation was associated with a higher risk of cup migration (6/13 vs. 2/36, X2 = 11.5, P = 0.0007). Cup migration was associated with an increased risk for all cause revision (4/8 vs. 3/38, X2 = 9.96, P = 0.0016, but not with dislocation (3/8 vs. 8/41, X2 = 1.2, P = 0.26). CONCLUSION: The results suggest that failure to achieve adequate ischial fixation, with screws passing through the flange of the custom component into the ischium, increases the risk of cup migration, which, in turn, is a risk factor for revision.

Characterization of per- and polyfluoroalkyl substances on fire suppression system piping and optimization of removal methods.

Fire suppression systems are known to be impacted with residual, entrained per- and polyfluoroalkyl substances (PFASs) because of historical use of aqueous film forming foam (AFFF) and fluoroprotein foam. Amphiphilic PFASs aggregate at liquid:solid interfaces creating a hydrophobic layer which reduces the effectiveness of water to remove PFAS from layered surfaces. When fire suppression systems are transitioned to fluorine free foam (F3) without appropriate cleaning, residual PFASs associated with the surfaces of the fire suppression system can contaminate the replacement F3. Release of residual PFASs from fire suppression systems into F3 has been documented; however, little is known about the residual PFASs associated with the surfaces of the fire suppression systems. More information is needed to develop methods to appropriately remove PFASs from fire suppression systems to prevent costly and inefficient foam transitioning and preserve the PFAS-free benefit of F3. The objective of this work was to evaluate the distribution and composition of PFASs on hangar piping exposed to PFAS-containing firefighting foam for a prolonged period. Two assessment methods were used: 1) extractions with methanol, water, and a proprietary aqueous organic solvent (Fluoro Fighter™); and 2) direct imaging methods of the surface. Extractions were analyzed with mass spectrometry and combustion ion chromatography. Results indicate pipe in contact with PFAS-containing firefighting foam can amass approximately 10 µg/cm2 of surface-associated PFAS residual following decades of exposure. Fluoro Fighter demonstrated higher PFAS removal per surface area of pipe than methanol (p = 0.007) or water extraction (p < 0.0001). Scanning electron microscope (SEM) images of the hangar piping reveal deposits suspected to be self-assembled PFAS layers, as evidenced by examination of pipe surfaces using X-ray photoelectron spectroscopy (XPS), which revealed atomic fluorine on the surface of the pipe.

Pleiotrophin Interaction with Synthetic Glycosaminoglycan Mimetics.

Chondroitin sulfate (CS) E is the natural ligand for pleiotrophin (PTN) in the central nervous system (CNS) of the embryo. Some structures of PTN in solution have been solved, but no precise location of the binding site has been reported yet. Using 15N-labelled PTN and HSQC NMR experiments, we studied the interactions with a synthetic CS-E tetrasaccharide corresponding to the minimum binding sequence. The results agree with the data for larger GAG (glycosaminoglycans) sequences and confirm our hypothesis that a synthetic tetrasaccharide is long enough to fully interact with PTN. We hypothesize that the central region of PTN is an intrinsically disordered region (IDR) and could modify its properties upon binding. The second tetrasaccharide has two benzyl groups and shows similar effects on PTN. Finally, the last measured compound aggregated but beforehand, showed a behavior compatible with a slow exchange in the NMR time scale. We propose the same binding site and mode for the tetrasaccharides with and without benzyl groups.

Patient Impressions and Outcomes After Clinic-Based Hidradenitis Suppurativa Surgery.

IMPORTANCE: Surgical intervention is frequently needed to treat hidradenitis suppurativa (HS). Patient satisfaction is high based on previous studies, but reports of patient impressions of clinic-based operative experiences and postoperative recovery are limited. OBJECTIVE: To characterize patient impressions, outcomes, and recovery time after clinic-based surgical treatment of HS and examine patient characteristics associated with outcomes. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study included patients 12 years or older who underwent clinic-based surgical procedures for treatment of HS at a single subspecialty HS clinic at the University of North Carolina Department of Dermatology from April 2014 to December 2018. Data analysis was performed from January to September 2021. EXPOSURES: Clinic-based deroofing and excisional procedures performed as part of routine care. MAIN OUTCOMES AND MEASURES: The primary outcomes were patient-reported recurrence of HS at the site of surgery, patient satisfaction with the procedures and outcomes, and patient-reported pain and recovery associated with surgery obtained from electronic medical record review and patient questionnaires. RESULTS: Outcomes of 194 procedures for 78 patients (65 [83%] female; mean [SD] age, 35.1 [12.1] years) were analyzed. Self-reported rate of recurrence was 41% (79 procedures). Despite recurrence, most patients (148 procedures [76%]) were very satisfied with their surgical results. The median number of missed days of work or school was 2 (IQR, 1-7 days), and the median number of days until return to normal activity was 10 (IQR, 3-14 days). In addition, for 126 of the 194 procedures (65%), patients stated that pain during an HS flare was worse than pain during surgical recovery. CONCLUSIONS AND RELEVANCE: In this cohort study, patients reported high rates of satisfaction with clinic-based HS surgery. Recovery was typically rapid, with most patients rating postsurgical pain as less severe than their HS pain.

Midkine Interaction with Chondroitin Sulfate Model Synthetic Tetrasaccharides and Their Mimetics: The Role of Aromatic Interactions.

Midkine (MK) is a neurotrophic factor that participates in the embryonic central nervous system (CNS) development and neural stem cell regulation, interacting with sulfated glycosaminoglycans (GAGs). Chondroitin sulfate (CS) is the natural ligand in the CNS. In this work, we describe the interactions between a library of synthetic models of CS-types and mimics. We did a structural study of this library by NMR and MD (Molecular Dynamics), concluding that the basic shape is controlled by similar geometry of the glycosidic linkages. Their 3D structures are a helix with four residues per turn, almost linear. We have studied the tetrasaccharide-midkine complexes by ligand observed NMR techniques and concluded that the shape of the ligands does not change upon binding. The ligand orientation into the complex is very variable. It is placed inside the central cavity of MK formed by the two structured beta-sheets domains linked by an intrinsically disordered region (IDR). Docking analysis confirmed the participation of aromatics residues from MK completed with electrostatic interactions. Finally, we test the biological activity by increasing the MK expression using CS tetrasaccharides and their capacity in enhancing the growth stimulation effect of MK in NIH3T3 cells.

Clinical Outcome of Free Latissimus Dorsi Flaps for Coverage of Soft Tissue Defects in Multiply Revised Total Knee Arthroplasties.

BACKGROUND: Multiply revised total knee arthroplasties (TKAs) may present with large anterior soft tissue defects, which can be challenging to reconstruct. In the rare cases where local flaps are insufficient, we use free latissimus dorsi (LD) myocutaneous flaps to achieve soft tissue coverage. This study looked to determine implant survivorship, infection status, and patient-reported outcomes of patients undergoing simultaneous revision TKA and LD flaps in a tertiary unit. METHODS: This was a retrospective study of 18 consecutive patients who had revision TKA and free LD flap reconstruction. Twelve were male and the median age was 65 years (range, 35-83). Patients had undergone a median of 4 previous arthroplasty procedures (range, 3-6). Median follow-up was 49 months (range, 18 to 110). The primary outcome was revision-free implant survival. Secondary outcomes included soft tissue integrity, Oxford Knee Score, and EuroQol 5-domain score at latest follow-up. RESULTS: At latest follow-up, 14 of 18 patients had maintained their implant. Seven patients were infection-free, 7 were on suppressive antibiotics with the implant in situ, and 4 had undergone above-knee amputation. Five-year implant survival was 75% (95% confidence interval, 46-90). At median follow-up (49 months), mean Oxford Knee Score was 13.4 (range, 2-35) and mean EuroQol 5-domain index was 0.071 (range:-0.427 to 0.747). CONCLUSION: LD free flap is a viable option for limb salvage in patients with large anterior soft tissue defects following multiple revisions of TKA. However, functional outcomes can be poor and there is a significant risk of ongoing infection and amputation in this complex patient cohort.

Stem cell transplantation for the treatment of osteochondral defects of the knee: Operative technique for a single-stage transplantation procedure using bone marrow-derived mesenchymal stem cells.

BACKGROUND: Autologous chondrocyte implantation (ACI) is a NICE-approved technique to regenerate hyaline cartilage in chondral and osteochondral defects (OCDs). The drawbacks of ACI include that it requires a two-stage approach, involves a lengthy rehabilitation process and is expensive. Bone marrow harvest with mesenchymal stem cell transplantation using a single-stage procedure and an accelerated rehabilitation programme has been developed to overcome this. The aim of this paper is to describe the surgical technique for stem cell transplantation of the knee for OCDs with reference to case examples. METHODS: The surgical technique for stem cell transplantation of the knee for OCDs is described, with reference to three cases. Magnetic resonance imaging was performed at six months postoperatively. RESULTS: The surgical technique is described in this paper. The three patient cases described all improved clinically with reduced pain and improved function at a minimum of six months follow-up. CONCLUSIONS: Stem cell transplantation has the potential to produce favourable outcomes for patients with osteochondral defects of the knee. This single-stage approach and accelerated rehabilitation is associated with reduced financial costs. A long-term prospective study of this technique is currently underway at our institution and randomised controlled trials are planned to demonstrate the effectiveness over other techniques.

Infected prosthetic knee replacement: What to do and what not to do.

This article is an expansion of a lecture given in the British Orthopaedic Association (BOA) Congress in Liverpool in 2019 as part of a symposium on infected knee replacement. It is designed to provide pointers and advice to surgeons on how these patients can be referred, investigated, and managed. The management of periprosthetic infection necessitates many decisions to be made to provide the patient with the best advice and treatment. This is a discussion of the philosophies of periprosthetic knee infection. It is not a definitive guide nor a metanalysis of scientific papers. These are the subjective views of the author and generalise decision making. All decisions should remain tailored to the patient's needs.

The uncrossed-doubled patellar tendon: A novel imaging finding.

A spectrum of anatomic variants of the conventional single patellar tendon have been described however a double patellar tendon is a highly rare finding, which has only been described once before where a cross-over tendon morphology was illustrated. We report the case of a 46-year-old man with a 3 month history of left knee pain who was found to have an incidental double patellar tendon without cross-over, with one deep bundle demonstrating a more conventional patellar tendon course, paralleled by a second anatomically-distinct superficial bundle of differing morphology coursing anterolateral to the deep conventional bundle, explicitly connecting patella to tibial tuberosity. A comprehensive understanding of the anatomic variations of the patellar tendon is essential for both radiologist and clinician to deliver safe clinical practice. We present a rare case of an uncrossed-doubled patellar tendon, which to our knowledge, has never been reported.

Partial Resurfacing of the Knee with the BioPoly Implant: Interim Report at 2 Years.

BACKGROUND: Current treatments for focal chondral and osteochondral lesions of the femoral condyle have been associated with variable outcomes. We conducted a clinical trial of the BioPoly RS Partial Resurfacing Knee Implant to address this unmet need. METHODS: We performed a single-arm, prospective study in which 33 patients with focal cartilage lesions affecting the femoral condyle were managed with the BioPoly RS Partial Resurfacing Knee Implant. Knee injury and Osteoarthritis Outcome Score (KOOS) scores, a visual analog scale (VAS) for pain, the Short Form-36 (SF-36) physical component score , and the Tegner activity score were used to assess outcomes preoperatively and at 6 months, 1 year, and 2 years postoperatively. The KOOS outcomes at 2 years were compared with historical outcomes following microfracture treatment. RESULTS: We found significant and clinically meaningful improvements in the KOOS scores, VAS pain score, and SF-36 physical component score (p < 0.025) when the values at all 3 postoperative time points were compared with the preoperative scores, and we also found significant improvements when the Tegner activity score at 2 years was compared with the preoperative score (p < 0.025). More than half of the cohort of patients had had a previous failure of cartilage-repair procedures. No significant differences were detected between younger patients (≤40 years) and older patients (>40 years). When compared with historical microfracture data, the BioPoly RS Implant demonstrated significantly superior KOOS scores for quality of life and sports. CONCLUSIONS: The present study indicated that the BioPoly RS Partial Resurfacing Knee Implant is safe, that it resulted in significantly improved knee function by 6 months, and that this improvement was sustained for 2 years regardless of patient age. The BioPoly RS Knee Implant allows return to a higher level of sporting activity than microfracture. Additional long-term follow-up is needed to determine the long-term effects of the device. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Medial Patellofemoral Ligament Reconstruction in a Below-Knee Amputee.

Patellar instability is a common finding in patients with below-knee amputation and yet management options are not commonly described in the literature. We describe the first reported case of a medial patellofemoral ligament reconstruction using allograft in a patient with a below-knee amputation. Clinical outcome at two-year follow-up remains very good.

Combined Vascular and Orthopaedic Approach for a Pseudotumor Causing Deep Vein Thrombosis after Metal-on-Metal Hip Resurfacing Arthroplasty.

Introduction. Metal-on-metal (MoM) hip resurfacings have been associated with a variety of complications resulting from adverse reaction to metal debris. Pseudotumors have rarely been reported to cause deep venous thrombosis (DVT). Study Design. A case report and a review of the literature. Case Presentation. A 75-year-old female who had left metal-on-metal hip resurfacing 6 years ago presented with left groin pain associated with unilateral lower limb edema and swelling. By duplex and MRI studies, our patient had an extensive soft tissue necrosis associated with a large pelvic mass causing extensive DVT of the lower limb secondary to mechanical compression of the left iliac vein. Results. Our case was initially treated for DVT followed by dual surgical approach. The pseudotumor was excised through a separate iliofemoral approach and revision of the hip implant was undertaken through a posterior approach in the same setting. An inferior vena cava (IVC) filter was inserted to minimise the perioperative risks of handling the iliac veins. Conclusion. A combined approach with vascular surgeons is required. Combined resection of the pseudotumor and revision of the metal bearing surfaces is essential, in order to achieve a good surgical outcome in this rare complication.

Functional outcome following primary total knee arthroplasty cannot be predicted using the initial post-operative radiograph.

Obtaining standardised post-operative radiographs following total knee arthroplasty is common practice. Little is known regarding how measurements taken from the initial post-operative radiograph correlate to functional outcome. The initial post-operative radiographs for 110 primary total knee arthroplasties were reviewed retrospectively. Femoral and tibial component alignment was measured by two independent consultant radiologists. Functional outcome was assessed by the Oxford Knee Score pre-operatively and one year post-operatively. Correlation was determined by Pearson correlation analysis. There was no significant correlation between the radiographic measurements with the one year post-operative Oxford Knee Score nor was there significant correlation with the difference in pre-operative and post-operative scores. The initial post-operative radiograph cannot be used as a tool to reliably predict functional outcome at one year.

Gait assessment as a functional outcome measure in total knee arthroplasty: a cross-sectional study.

BACKGROUND: The aim of the study was to assess gait in total knee arthroplasty (TKA) patients, using a technique that can to be used on a routine basis in a busy orthopaedic clinic. METHODS: A total of 103 subjects were recruited: 29 pre-op TKA patients; 17 TKA patients at 8 weeks post-op; 28 TKA patients at 52 weeks post-op; and 29 age-matched controls. Inertial measurement units (IMUs) were used to assess gait. Limb segment angles, knee angle and temporal parameters of gait were calculated. Specific gait parameters were quantified, and data analysed using MANOVA and discriminant analysis. RESULTS: The gait of TKA patients as a group was only slightly improved at 12 months when compared with the pre-operative group, and both groups were significantly different to controls in several variables. Knee flexion range in stance was the most important variable in discriminating between patients and controls; knee flexion range in swing was the only variable that showed a significant difference between pre- and post-operative patients. When considered individually, only 1/29 patient was within the normal range for this variable pre-operatively, but 9/28 patients were within the normal range 12 months post-operatively. CONCLUSIONS: Even after 12 months after surgery, many TKA patients have not improved their gait relative to pre-operative patients. Routine gait assessment may be used to guide post-operative rehabilitation, and to develop strategies to improve mobility of these patients.

A new approach to managing patients with problematic metal hip implants: the use of an Internet-enhanced multidisciplinary team meeting: AAOS exhibit selection.

BACKGROUND: Over one million patients worldwide are estimated to have a metal-on-metal hip arthroplasty. To improve the management of these patients and reduce surgeon uncertainty regarding decision-making, we designed an Internet-enhanced multidisciplinary team (iMDT) working approach. METHODS: From August 2012 to April 2014, the iMDT discussed 215 patients with 266 metal-on-metal hip arthroplasties. Of these, 236 primary arthroplasties (132 hip resurfacing and 104 total hip) were analyzed. The remaining thirty cases involved problematic revised hips and were therefore excluded. The possible recommendations of the iMDT were monitoring, further investigation, or surgery. The concordance between the recommendation and the actual management was used to assess the usefulness of this approach in reducing uncertainty in surgeon-level decision-making. RESULTS: The median Oxford Hip Score was 35 (range, 4 to 48), and median cobalt and chromium levels in whole blood were 3.54 ppb (range, 0.18 to 161.46 ppb) and 3.17 ppb (range, 0.20 to 100.67 ppb), respectively. Magnetic resonance imaging revealed abductor muscle atrophy in ninety-two (39%) of the hips and a pseudotumor in eighty (34%). The iMDT recommended monitoring of 146 (61.9%) of the hips, further investigation of thirty (12.7%), and surgery in sixty (25.4%). The actual outcome was concordant with the recommendation in 211 (91.7%) of the hips. CONCLUSIONS: Our iMDT approach to the metal-on-metal hip burden combines the tacit knowledge of an expert panel, regulatory guidance, and up-to-date evidence to improve decision-making among surgeons. The high level of concordance between the recommendation and the actual outcome, combined with the feasibility of the methods used, suggest that this method effectively reduces uncertainty among surgeons and may lead to improved patient outcomes.

Muscle atrophy and metal-on-metal hip implants: a serial MRI study of 74 hips.

BACKGROUND AND PURPOSE: Muscle atrophy is seen in patients with metal-on-metal (MOM) hip implants, probably because of inflammatory destruction of the musculo-tendon junction. However, like pseudotumors, it is unclear when atrophy occurs and whether it progresses with time. Our objective was to determine whether muscle atrophy associated with MOM hip implants progresses with time. PATIENTS AND METHODS: We retrospectively reviewed 74 hips in 56 patients (32 of them women) using serial MRI. Median age was 59 (23-83) years. The median time post-implantation was 83 (35-142) months, and the median interval between scans was 11 months. Hip muscles were scored using the Pfirrmann system. The mean scores for muscle atrophy were compared between the first and second MRI scans. Blood cobalt and chromium concentrations were determined. RESULTS: The median blood cobalt was 6.84 (0.24-90) ppb and median chromium level was 4.42 (0.20-45) ppb. The median Oxford hip score was 34 (5-48). The change in the gluteus minimus mean atrophy score between first and second MRI was 0.12 (p = 0.002). Mean change in the gluteus medius posterior portion (unaffected by surgical approach) was 0.08 (p = 0.01) and mean change in the inferior portion was 0.10 (p = 0.05). Mean pseudotumor grade increased by 0.18 (p = 0.02). INTERPRETATION: Worsening muscle atrophy and worsening pseudotumor grade occur over a 1-year period in a substantial proportion of patients with MOM hip implants. Serial MRI helps to identify those patients who are at risk of developing worsening soft-tissue pathology. These patients should be considered for revision surgery before irreversible muscle destruction occurs.