Mechanical failure of distal femur mega prosthesis due to polyaryl-ether-ether-ketone (PEEK) hinge component.

BACKGROUND: Polyaryl-ether-ether-ketone (PEEK) has gained popularity as a substrate for orthopaedic hardware due to its desirable properties such as heat and deformation resistance, low weight, and ease of manufacturing. However, we observed a relatively high failure rate of PEEK-based hinges in a distal femur reconstruction system. In this study, we aimed to evaluate the proportion of patients who experienced implant failure, analyse the mechanism of failure, and document the associated clinical findings. METHODS: We conducted a retrospective cohort study, reviewing the medical charts of 56 patients who underwent distal femur resection and reconstruction with a PEEK Optima hinge-based prosthesis between 2004 and 2018. Concurrently, we performed a clinical and biomechanical failure analysis. RESULTS: PEEK component failure occurred in 21 out of 56 patients (37.5%), with a mean time to failure of 63.2 months (range: 13-144 months, SD: 37.9). The survival distributions of PEEK hinges for males and females were significantly different (chi-square test, p-value = 0.005). Patient weight was also significantly associated with the hazard of failure (Wald's test statistic, p-value = 0.031). DISCUSSION: Our findings suggest that PEEK hinge failure in a distal femur reconstruction system is correlated with patient weight and male gender. Retrieval analysis revealed that failure was related to fretting and microscopic fractures due to cyclic loading, leading to instability and mechanical failure of the PEEK component in full extension. Further assessment of PEEK-based weight bearing articulating components against metal is warranted.

Internal Hemipelvectomy for primary bone sarcomas using intraoperative patient specific instruments- the next step in limb salvage concept.

BACKGROUND: During pelvic Sarcoma resections, Surgeons often struggle to obtain negative margins while minimizing collateral damage and maintaining limb function. These complications are usually due to the complex anatomy of the pelvis. Here we present an accurate 3D surgical approach, including pre-operative printing of models and intraoperative patient-specific instruments (PSIs) for optimizing pelvic sarcoma resections. METHODS: This single-center retrospective study (N = 11) presents surgical, functional, and oncological outcomes of patients (average age 14.6 +/- 7.6 years, 4 males) who underwent pelvic sarcoma resections using a 3D surgical approach between 2016 and 2021. All patients were followed up for at least 24 months (mean = 38.9 +/- 30.1 months). RESULTS: Our results show promising surgical, oncological, and functional outcomes. Using a 3D approach, 90.9% had negative margins, and 63.6% did not require reconstruction surgery. The average estimated blood loss was 895.45 ± 540.12 cc, and the average surgery time was 3:38 ± 0.05 hours. Our results revealed no long-term complications. Three patients suffered from short-term complications of superficial wound infections. At 24 month follow up 72.7% of patients displayed no evidence of disease. The average Musculoskeletal Tumor Society (MSTS) score at 12 months was 22.81. CONCLUSION: 3D technology enables improved accuracy in tumor resections, allowing for less invasive procedures and tailored reconstruction surgeries, potentially leading to better outcomes in function and morbidity. We believe that this approach will enhance treatments and ease prognosis for patients diagnosed with pelvic sarcoma and will become the standard of care in the future.

Intraoperative three-dimensional navigation for surgical treatment of osteoid osteoma in the foot and ankle - A series of 14 cases.

BACKGROUND: The surgical treatment for osteoid osteoma (OO) in the foot and ankle is challenging. It is difficult to locate the lesion and the anatomy is crowded by sensitive structures. The purpose of this study was to describe the outcomes of navigated mini open-intralesional curettage (NMIC) or navigated minimally invasive radiofrequency ablation (NMRFA) in treating these lesions. METHODS: All patients who underwent surgery for OO in the foot and ankle between 2015 and 2020 were included. O-arm navigation was used in All procedures. The choice of NMIC versus NMRFA was made by the surgeon according to the location of the lesion and its proximity to sensitive anatomic structures. RESULTS: Fourteen patients were included. Ten were operated by NMRFA and 4 by NMIC. All patients' symptoms related to OO resolved following a single procedure. Average AOFAS score increased by 18.7 (P < .001). Three patients had the following complications: pathologic fracture, superficial infection and transient deep peroneal nerve sensory loss. CONCLUSION: Navigated surgical treatment of OO in the foot and ankle is accurate, efficient and safe.

Cryo-surgery for symptomatic extra-abdominal desmoids. A proof of concept study.

BACKGROUND AND OBJECTIVE: Extra abdominal desmoid tumors are rare, highly aggressive, and invasive benign soft tissue tumors. Current treatment modalities show high levels of recurrence and comorbidities. Cryo-surgery as an alternative was subsequently investigated. METHODS: In this retrospective, single center study 11 patients showing symptomatic tumors were treated with individualized cryo-surgery. Treatment protocol included preoperative planning using computer rendered 3D models, intraoperative navigation and execution using cone beam guidance, and postoperative magnetic resonance imaging image analysis using a gaussian mixture model software. Subjective outcomes were reported using Short Form Health Survey (SF-36) questionnaires. RESULTS: Sixteen ablations were performed, each demonstrating a complete match with the determined preoperative plan and model. A total of 9/11 (82%) of patients showed improvements in symptoms and a reduction in tumor volume while 2/11 (18%) did not. Average reduction in tumor volume and viable segments were 36.7% (p = 0.0397) and 63.3% (p = 0.0477), respectively. Mild complications according to the SIR Adverse Event Classification Guidelines were experienced in 3/16 (19%) ablations. SF-36 scores showed a statistically significant improvement (p = 0.0194) in the mental health category and a nonsignificant (p = 0.8071) improvement in the physical health category. CONCLUSION: Cryo-surgery using the three-phase protocol as described may improve the overall outcome of future ablation procedures.

Antegrade versus retrograde nailing techniques and trochanteric versus piriformis intramedullary nailing entry points for femoral shaft fractures: a systematic review and meta-analysis.

BACKGROUND: There are several different techniques commonly used to perform intramedullary (IM) nailing of the femur to fix femoral fractures. We sought to identify significant differences in outcomes of studies comparing 1) trochanteric and piriformis entry and 2) antegrade and retrograde entry in IM nailing of the femur. METHODS: We searched MEDLINE, Cochrane and Embase databases and the Orthopaedic Trauma Association and American Academy of Orthopaedic Surgeons websites for comparative studies published from inception to November 2015. Criteria used to select articles for detailed review included use of antegrade and retrograde entry point or use of trochanteric and piriformis entry point for IM nailing of the femur in adult patients. Functional and technical outcomes were extracted from accepted studies. RESULTS: We identified 483 potential studies, of which 52 were eligible. Of these, we included 13 publications and 2 abstracts (2 level I, 7 level II and 6 level III studies). Trochanteric entry significantly reduced operative duration by 14 min compared with piriformis entry (p = 0.030). Retrograde nailing had a greater risk of postoperative knee pain than antegrade nailing (p = 0.05). On the other hand, antegrade nailing had significantly more postoperative hip pain (p = 0.003) and heterotopic ossification (p < 0.001) than retrograde nailing. No significant differences in functional outcomes were observed. CONCLUSION: Although some significant differences were found, the varying quality of studies made recommendation difficult. Our meta-analysis did not confirm superiority of either antegrade over retrograde or trochanteric over piriformis entry for IM nailing of the femur. LEVEL OF EVIDENCE: Level III therapeutic.

CONTEXTE: Plusieurs techniques différentes sont couramment utilisées pour l'enclouage intramédullaire (IM) du fémur afin d'immobiliser les fractures fémorales. Nous avons voulu dégager les différences significatives sur le plan des résultats d'études ayant comparé 1) l'entrée par le trochanter et par la fossette piriforme et 2) l'entrée par voies antérograde et rétrograde pour l'enclouage IM du fémur. MÉTHODES: Nous avons interrogé les bases de données MEDLINE, Cochrane et EMBASE et les sites Web de l'Orthopaedic Trauma Association et de l'American Academy of Orthopaedic Surgeons pour recenser les études comparatives publiées depuis leur création et jusqu'en novembre 2015. Les critères utilisés pour la sélection des articles en vue d'un examen détaillé incluaient l'utilisation de points d'entrée antérograde et rétrograde ou du trochanter et de la fossette piriforme pour l'enclouage IM du fémur chez des patients adultes. Les résultats fonctionnels et techniques ont été dégagés des études retenues. RÉSULTATS: Nous avons recensé 483 études potentielles, dont 52 se sont révélées admissibles. Parmi elles, nous avons inclus 13 publications et 2 résumés (2 études de niveau I, 7 de niveau II et 6 de niveau III). Le point d'entrée par le trochanter a significativement réduit la durée des interventions, soit de 14 min, comparativement à l'entrée par la fossette piriforme (p = 0,030). L'enclouage rétrograde a comporté un risque plus élevé de douleur postopératoire au genou comparativement à l'enclouage antérograde (p = 0,05). Par ailleurs, l'enclouage antérograde a donné lieu à significativement plus de douleur à la hanche (p = 0,003) et d'ossification hétérotopique (p < 0,001) postopératoires comparativement à l'enclouage rétrograde. Aucune différence significative n'a été observée sur le plan des résultats fonctionnels. CONCLUSION: Même si nous avons noté quelques différences significatives, la qualité variable des études nous empêche de formuler des recommandations. Notre métaanalyse n'a pas confirmé la supériorité du point d'entrée antérograde plutôt que rétrograde ou par le trochanter plutôt que par la fossette piriforme pour l'enclouage IM du fémur. NIVEAU DE PREUVE: Niveau III thérapeutique.

The effect of the setting of a positive surgical margin in soft tissue sarcoma.

BACKGROUND: The objectives of this study were to evaluate the risk of local recurrence and survival after soft tissue sarcoma (STS) resection with positive margins and to evaluate the safety of sparing adjacent critical structures. METHODS: One hundred sixty-nine patients with localized STS who had positive resection margins were identified from a prospective database. Patients who had positive margins were stratified into 3 groups, each representing a specific clinical scenario: critical structure positive margin (eg major nerve, vessel, or bone), tumor bed resection positive margin, and unexpected positive margin. The rates of local recurrence-free survival (LRFS) and cause-specific survival (CSS) were calculated and compared with relevant control patients who had negative margins after STS resection. RESULTS: After planned close dissection to preserve critical structures, the 5-year LRFS and CSS rates both depended on the quality of the surgical margins (97% and 80.3%, respectively, for those with negative margins vs 85.4% and 59.4%, respectively, for those with positive margins; P = .015 and P = .05, respectively). Negative margins achieved through resection of critical structures because of tumor invasion or encasement only slightly improved the 5-year rates of LRFS (91.2%) and CSS (63.6%; P = .8 and P = .9, respectively). The lowest 5-year LRFS and CSS rates were 63.4% and 59.2%, respectively, after an unexpected positive margin during primary surgery. CONCLUSIONS: After patients undergo resection of STS with positive margins, oncologic outcomes can be predicted based on the clinical context. Sparing adjacent critical structures in this setting is safe and contributes to improved functional outcomes.

Two-stage revision arthroplasty for management of chronic periprosthetic hip and knee infection: techniques, controversies, and outcomes.

In North America, two-stage revision arthroplasty is the treatment of choice for chronic periprosthetic infection of the hip and knee. Controversy exists regarding the diagnosis of persistent infection, cement spacer design, and duration of antibiotic therapy. Erythrocyte sedimentation rate and C-reactive protein tests have no clear cutoff values for detecting infection before reimplantation of hardware, and aspiration for microbial culture can yield false-negative results. Mobile spacers are as effective as static spacers for eradicating infection, but mobile spacers provide better interim function and may help to make the second stage of surgery technically easier. Some articulating spacer designs have fewer reports of spacer dislocation and fracture than do others. Although prolonged antibiotic therapy has been the standard of care for two-stage procedures, some have suggested that a short course of antibiotics is just as effective. When infection persists despite antibiotic therapy, the second stage of revision arthroplasty should be delayed until the first stage of the procedure is repeated.

Transient sternoclavicular joint arthropathy, a self-limited disease.

BACKGROUND: The sternoclavicular joint (SCJ) is a true diarthrodial synovial joint and therefore vulnerable to the same disease processes as in other synovial joints. We identified a group of patients with monarticular arthritis of the SCJ that had a benign process and a self-limited disease course. METHODS: This retrospective study included 25 female patients who presented with pain or swelling of the SCJ between January 2000 and December 2010. Their mean age was 59 years, and the average follow-up was 44 months. All patients underwent baseline radiographic imaging, technetium bone scan, computed tomography, and magnetic resonance imaging. Blood profiles were negative for rheumatoid factor in all patients. Functional outcome was assessed with the Rockwood SCJ score. RESULTS: The patients presented with complaints of pain (72%), local swelling (88%), and redness (8%) that progressed during 4 weeks. The physical examination revealed tenderness (84%), swelling (88%), and limited range of motion (16%). These findings persisted for a median of 5 months. Plain radiographs showed arthritic changes in 5 patients (20%). Increased uptake was observed in all 9 patients who underwent a bone scan. Soft tissue swelling was demonstrated on computed tomography in 5 patients (20%) and on magnetic resonance imaging in 5 patients (20%). One patient had osteoarthritic changes on magnetic resonance imaging. Pain resolved spontaneously in all patients, leaving only swelling in 9 patients and tenderness in 1 patient. CONCLUSION: Our experience is that SCJ arthropathy may often be a self-limited disease. After being treated solely with nonsteroidal anti-inflammatory medication, 24 of the 25 study patients showed complete regression of pain and return to full function without recurrence of symptoms. Basic blood tests and radiographs are sufficient to rule out a septic joint.

Treatment of large bone defects with trabecular metal cones in revision total knee arthroplasty: short term clinical and radiographic outcomes.

The early term results of 29 cases of revision total knee arthroplasty using highly porous trabecular metal cone implants for femoral and tibial major bone deficit reconstruction (Anderson Orthopedic Research Institute classification type 2B and 3) have been prospectively analyzed. Indications for revision surgery included: aseptic loosening/wear, staged reimplantation after infection, as well as periprosthetic fracture. At an average follow-up of 33 months (range, 13-73 months) the mean Knee Society Score and functional score statistically improved. Radiological follow-up revealed no evidence of loosening or migration of the constructs. No evidence of complications was noted in correlation with the use of trabecular metal cones. This study supports evidence that trabecular metal cones are an efficient and effective option for dealing with significant bone deficits and obtaining stable biological fixation in revision total knee arthroplasty.

Effect of patellar thickness on knee flexion in total knee arthroplasty: a biomechanical and experimental study.

A biomechanical computer-based model was developed to simulate the influence of patellar thickness on passive knee flexion after arthroplasty. Using the computer model of a single-radius, PCL-sacrificing knee prosthesis, a range of patella-implant composite thicknesses was simulated. The biomechanical model was then replicated using two cadaveric knees. A patellar-thickness range of 15 mm was applied to each of the knees. Knee flexion was found to decrease exponentially with increased patellar thickness in both the biomechanical and experimental studies. Importantly, this flexion loss followed an exponential pattern with higher patellar thicknesses in both studies. In order to avoid adverse biomechanical and functional consequences, it is recommended to restore patellar thickness to that of the native knee during total knee arthroplasty.

Treatment of failed allograft prosthesis composites used for hip arthroplasty in the setting of severe proximal femoral bone defects.

This study assessed failures of allograft prosthesis composites (APC) and revisions with a new APC. Twenty-one patients with failed APC's after revision hip arthroplasty with severe proximal femoral bone loss underwent revision with a new APC. Causes of failure were aseptic loosening (18 patients), infection (3 patients). Of these 21 APC revisions, two patients failed (after 60, 156 months). The 5 and 10 year survival rates were 83.5% (95% CI, 79-100%, number at risk 12 and 6 accordingly). In addition, two patients had non-union at the host-allograft bone junction and were augmented with bone autograft and plate. These results suggest that failed APCs may be revised to a new APC with a predictable outcome.

Early operative intervention is associated with better patient survival in patients with intracapsular femur fractures but not extracapsular fractures.

The purpose of this study was to determine patients' survival after undergoing an early or delayed operation. We retrospectively assessed 1849 files of patients operated for proximal femoral fracture, divided into two diagnostic groups: intracapsular (n = 640) and extracapsular (n = 1209). 1163 (63%) were treated within 48 h from hospital admission and 686 (37%) were treated >48 h afterwards. Delayed operation in patients with intracapsular fractures was associated with a 1.8-fold excess risk for 1-year mortality (HR = 1.83, P = 0.008), while no effect was observed for patients with extracapsular fractures. Males had a higher HR for mortality in both diagnostic groups. Early surgical intervention is beneficial for intra-capsular femoral fractures; male gender and a high ASA score are associated with an increased mortality hazard risk.

Early follow-up of a custom non-fluted diaphyseal press-fit tumour prosthesis.

PURPOSE: The objective of this study was to evaluate the early results of a custom non-fluted diaphyseal press-fit stem for use with the global modular replacement system (GMRS) tumour prosthesis and the early complications associated with this implant. METHODS: A total of 53 patients (54 implants) were identified from a prospective database where a custom non-fluted diaphyseal press-fit stem was used as part of the reconstruction of the limb. All patients had a minimum of 22 months of follow-up. RESULTS: The rates of stem revision for any reason were calculated. The median follow-up was 36 months (range 22-85 months). Aseptic loosening was not observed in any patient. CONCLUSIONS: At early term follow-up, an uncemented non-fluted stem used with the GMRS tumour endoprosthesis provides a stable bone-prosthesis interface with no evidence of aseptic loosening.

The influence of femoral lytic tumors segmentation on autonomous finite element analysis.

BACKGROUND: The validated CT-based autonomous finite element system Simfini (Yosibash et al., 2020) is used in clinical practice to assist orthopedic oncologists in determining the risk of pathological femoral fractures due to metastatic tumors. The finite element models are created automatically from CT-scans, assigning to lytic tumors a relatively low stiffness as if these were a low-density bone tissue because the tumors could not be automatically identified. METHODS: The newly developed automatic deep learning algorithm which segments lytic tumors in femurs, presented in (Rachmil et al., 2023), was integrated into Simfini. Finite element models of twenty femurs from ten CT-scans of patients with femoral lytic tumors were analyzed three times using: the original methodology without tumor segmentation, manual segmentation of the lytic tumors, and the new automatic segmentation deep learning algorithm to identify lytic tumors. The influence of explicitly incorporating tumors in the autonomous finite element analysis on computed principal strains is quantified. These serve as an indicator of femoral fracture and are therefore of clinical significance. FINDINGS: Autonomous finite element models with segmented lytic tumors had generally larger strains in regions affected by the tumor. The deep learning and manual segmentation of tumors resulted in similar average principal strains in 19 regions out of the 23 regions within 15 femurs with lytic tumors. A high dice similarity score of the automatic deep learning tumor segmentation did not necessarily correspond to minor differences compared to manual segmentation. INTERPRETATION: Automatic tumor segmentation by deep learning allows their incorporation into an autonomous finite element system, resulting generally in elevated averaged principal strains that may better predict pathological femoral fractures.

Automatic segmentation of femoral tumors by nnU-net.

BACKGROUND: Metastatic femoral tumors may lead to pathological fractures during daily activities. A CT-based finite element analysis of a patient's femurs was shown to assist orthopedic surgeons in making informed decisions about the risk of fracture and the need for a prophylactic fixation. Improving the accuracy of such analyses ruqires an automatic and accurate segmentation of the tumors and their automatic inclusion in the finite element model. We present herein a deep learning algorithm (nnU-Net) to automatically segment lytic tumors within the femur. METHOD: A dataset consisting of fifty CT scans of patients with manually annotated femoral tumors was created. Forty of them, chosen randomly, were used for training the nnU-Net, while the remaining ten CT scans were used for testing. The deep learning model's performance was compared to two experienced radiologists. FINDINGS: The proposed algorithm outperformed the current state-of-the-art solutions, achieving dice similarity scores of 0.67 and 0.68 on the test data when compared to two experienced radiologists, while the dice similarity score for inter-individual variability between the radiologists was 0.73. INTERPRETATION: The automatic algorithm may segment lytic femoral tumors in CT scans as accurately as experienced radiologists with similar dice similarity scores. The influence of the realistic tumors inclusion in an autonomous finite element algorithm is presented in (Rachmil et al., "The Influence of Femoral Lytic Tumors Segmentation on Autonomous Finite Element Analyses", Clinical Biomechanics, 112, paper 106192, (2024)).

Imaging-Based Deep Learning for Predicting Desmoid Tumor Progression.

Desmoid tumors (DTs) are non-metastasizing and locally aggressive soft-tissue mesenchymal neoplasms. Those that become enlarged often become locally invasive and cause significant morbidity. DTs have a varied pattern of clinical presentation, with up to 50-60% not growing after diagnosis and 20-30% shrinking or even disappearing after initial progression. Enlarging tumors are considered unstable and progressive. The management of symptomatic and enlarging DTs is challenging, and primarily consists of chemotherapy. Despite wide surgical resection, DTs carry a rate of local recurrence as high as 50%. There is a consensus that contrast-enhanced magnetic resonance imaging (MRI) or, alternatively, computerized tomography (CT) is the preferred modality for monitoring DTs. Each uses Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1), which measures the largest diameter on axial, sagittal, or coronal series. This approach, however, reportedly lacks accuracy in detecting response to therapy and fails to detect tumor progression, thus calling for more sophisticated methods. The objective of this study was to detect unique features identified by deep learning that correlate with the future clinical course of the disease. Between 2006 and 2019, 51 patients (mean age 41.22 ± 15.5 years) who had a tissue diagnosis of DT were included in this retrospective single-center study. Each had undergone at least three MRI examinations (including a pretreatment baseline study), and each was followed by orthopedic oncology specialists for a median of 38.83 months (IQR 44.38). Tumor segmentations were performed on a T2 fat-suppressed treatment-naive MRI sequence, after which the segmented lesion was extracted to a three-dimensional file together with its DICOM file and run through deep learning software. The results of the algorithm were then compared to clinical data collected from the patients' medical files. There were 28 males (13 stable) and 23 females (15 stable) whose ages ranged from 19.07 to 83.33 years. The model was able to independently predict clinical progression as measured from the baseline MRI with an overall accuracy of 93% (93 ± 0.04) and ROC of 0.89 ± 0.08. Artificial intelligence may contribute to risk stratification and clinical decision-making in patients with DT by predicting which patients are likely to progress.

Does cryotherapy decrease the local recurrence rate in the treatment of an aneurysmal bone cyst? A comparative assessment.

Curettage with or without the use of adjuvants is the standard of care in the treatment of an aneurysmal bone cyst (ABC). Historically, our approach combined curettage, high-speed burr drilling, and cryoablation. However, treatments varied based on age, tumor location, and surgeon preference. We asked: (1) Does cryoablation in addition to curettage and burr drilling decrease the local recurrence rates? (2) Are there any risk factors for the local recurrence rate? (3) Does cryoablation improve postsurgical functional outcomes in these patients? Patients treated for an ABC, between January 2006 and December 2019 were included in this retrospective analysis. Patient and surgical characteristics, such as age, gender, tumor location, type of treatment, time of follow-up, recurrence rate, and functional outcome measured by the Musculoskeletal Tumor Society Score 1993 (MSTS93) score were compared between those treated with and without cryoablation. Both groups, without cryoablation (n = 88) and with cryoablation (n = 42), showed no significant difference in local recurrence rates (9.1% vs. 7.1%, p = 0.553) and functional outcomes as measured by the MSTS93 score (28.9 vs. 27.8, p = 0.262). Risk factors analyzed did not significantly affect local recurrence risk, except for secondary ABC diagnosis (p = 0.017). The cryoablation group had a more extended follow-up (45.6 vs. 73.2 months, p < 0.001), reflecting a shift in practice over time. We found no significant difference in local recurrence rate or functional outcome in patients treated with or without cryoablation. Formal curettage with additional high-speed burr drilling provides effective tumor control and favorable functional outcomes, negating the need for adjuvant cryoablation.

Is arthroplasty immediately after an infected case a risk factor for infection?

BACKGROUND: It is common practice in many centers to avoid performing a clean case in a room in which an infected procedure has just taken place. No studies of which we are aware speak to the necessity of this precaution. QUESTIONS/PURPOSES: The purposes of this study were to identify (1) the risk of infection in a group of patients who underwent arthroplasties performed immediately after a first-stage arthroplasty for joint infection; and (2) the risk of superficial and deep infections in these patients compared with a matched group of patients who underwent arthroplasties not performed after an infected surgery. METHODS: Eighty-three patients (85 arthroplasties) who underwent arthroplasties (primary or revision) immediately after patients with known infections underwent surgery in the same operating room (OR) were analyzed for 12 months after surgery to determine the incidence of infection. They were matched for demographic factors and surgery type with a control group of 321 patients (354 arthroplasties) who underwent surgery in an OR that had not just been used for surgery involving patients with infections. We compared the risk of superficial and deep infections between the groups. RESULTS: Patients in the study group were not more likely to have infections develop than those in the control group. One patient in the study group (1.17%) and three in the control group (0.84%) had deep infections develop; the infection in the patient in the study group was caused by a different organism than that of the patient with an infection whose surgery preceded in the OR. Two superficial infections (2.35%) were detected in the study group and 17 (4.8%) were detected in the control group. CONCLUSIONS: With the numbers available, we found that a deep infection was not more likely to occur in a patient without an infection after an arthroplasty that followed surgery on a patient with an infection than in one who had surgery after a clean case. Although sample size was a potential issue in this study, the results may serve as hypothesis generating for future studies. LEVEL OF EVIDENCE: Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

The treatment of acquired patella baja with proximalize the tibial tuberosity.

PURPOSE: Acquired patella baja may result in decreased range of motion of the knee, extensor lag, and anterior knee pain. The aim of the study was to evaluate the efficacy of tibial tubercle osteotomy with proximal displacement. METHODS: Between 1998 and 2011, a proximalization of the tibial tuberosity was performed in 15 patients (15 knees) with patella baja diagnosed using the Blackburne-Peel ratio. Clinical outcomes included the Tegner Lysholm knee scoring scales, the WOMAC questionnaire, the short form-12 (SF-12), and a visual analogue score (VAS) pain scale. RESULTS: Fifteen proximalizations of the tibial tuberosity were performed, with a mean follow-up period of 64 months (5-160). The mean patient age was 59 years (41-86 years). The mean preoperative Blackburne-Peel ratio of 0.4 (0.1-0.6) was improved to a mean of 1.0 (0.8-1.2) post-operatively, which was associated with significant improvements in the Lysholm knee scoring scale from 13.3 ± 13.0 to 86.7 ± 10.4 points (p < 0.0001). Quality of life, as measured using the SF-12 outcome, also improved significantly (p < 0.0001), as did all WOMAC questionnaire score subscales (p < 0.0001). The VAS preoperative status for pain improved from 8.3 ± 2.0 to 1.5 ± 1.8. No patient had delayed or non-union of the osteotomy site. CONCLUSIONS: A series of patients with patella baja, treated with proximalization of the tibial tuberosity, achieved satisfactory outcomes in terms of pain relief and improved function, without major complication.

A long-term survivorship comparison between cemented and uncemented cups with shelf grafts in revision total hip arthroplasty after dysplasia.

Long-term outcomes of cemented and uncemented cups were compared in patients with hip dysplasia who had undergone revision hip arthroplasty. Patients had uncontained superolateral acetabular defects reconstructed with a structural allograft. This retrospective study compared 18 cemented acetabular cups to 27 uncemented acetabular cups. Average follow-up was 216 months (range, 96-312). Nineteen acetabular cups (42%) failed due to loosening and were revised. The 10- and 20-year cup survival was 88% and 76% in the uncemented group and 67% and 36% in the cemented group. Log rank analysis showed this difference to be significant (P = .0077). Uncemented acetabular cups performed significantly better than cemented cups.