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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_21 | Pages 17 - 17
1 Dec 2016
Degen R Nawabi D Fields K McLawhorn A Ranawat A Sink E Kelly B
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The outcomes of hip arthroscopy in the treatment of dysplasia are variable. Historically, arthroscopic treatment of severe dysplasia (lateral center-edge angle [LCEA] < 18°) resulted in poor outcomes and iatrogenic instability. However, in milder forms of dysplasia, favorable outcomes have been reported. The purpose of this study was to compare outcomes following hip arthroscopy for femorocetabular impingement (FAI) in borderline dysplastic (BD) patients compared with a control group of non-dysplastic patients.

Between March 2009 and July 2012, a BD group (LCEA 18°–25°) of 46 patients (55 hips) was identified. An age and sex-matched control group of 131 patients (152 hips) was also identified (LCEA 25°–40°). Patient-reported outcome scores, including the Modified Harris Hip Score (mHHS), the Hip Outcome Score-Activity of Daily Living (HOS-ADL), the Sport-specific Subscale (HOS-SSS), and the International Hip Outcome Tool (iHOT-33), were collected pre-operatively, at 1, and 2 years.

The mean LCEA was 22.4 ± 2.0° (range, 18.4°–24.9°) in the BD group and 31.0 ± 3.1° (range, 25.4°–38.7°) in the control group (p<0.001). The mean preoperative alpha angle was 66.3 ± 9.9° in the BD group and 61.7 ± 13.0° in the control group (p=0.151). Cam decompression was performed in 98.2% and 99.3% of cases in the BD and control groups. Labral repair was performed in 69.1% and 75.3% of the BD and control groups respectively, with 100% of patients having a complete capsular closure performed in both groups. At a mean follow-up of 31.3 ± 7.6 months (range, 23.1–67.3) in unrevised patients and 21.6 ± 13.3 months (range 4.7–40.6) in revised patients, there was significant improvement (p<0.001) in all patient reported outcome scores in both groups. Multiple regression analysis did not identify any significant differences between groups. Importantly, female sex did not appear to be a predictor for inferior outcomes. Two patients (4.3%) in the BD group and six patients (4.6%) in the control group required revision arthroscopy during the study period.

Favorable outcomes can be expected following the treatment of impingement in borderline dysplastics when labral refixation and capsular closure are performed, with comparable outcomes to non-dysplastic patients. Further follow-up in larger cohorts is necessary to prove the durability and safety of hip arthroscopy in this challenging group and to further explore potential gender-related differences in outcome.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 38 - 38
1 May 2016
Meftah M Nawabi D Ranawat A Ranawat C
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Background

Highly cross-linked polyethylene (HCLPE) was introduced to reduce wear and osteolysis in total hip arthroplasty (THA). There is no reported data regarding wear rates and clinical performance of Crossfire HCLPE (Stryker, Mahwah, New Jersey) in young and active patients. The purpose of this prospective study is to assess minimum 10-year wear rates and survivorship of Crossfire in young and active patients.

Material and Methods

Between January 2001 to December 2003, 52 consecutive THAs (43 patients; 26 males and 17 females), 55 years and younger, with an average University of California Los Angeles activity (UCLA) score of 7.3 ± 1.5 (5 – 10) at the time of surgery were prospectively followed. The mean age of patients was 47.4 ± 7.8 years old (range 24 to 55 years). Indication for surgery included osteoarthritis in all cases. All operations were performed by the senior surgeon via a posterolateral approach. All components were non-cemented SecurFit femoral stem, 28 mm Cobalt-Chromium (Co-Cr) femoral head, and Trident PSL cup with Crossfire HCLPE acetabular liner (Stryker, Mahwah, New Jersey). At minimum 10-years follow-up (mean 11.5 ± 0.94 years), wear rates were assessed using the Roman software. Hospital for Special Surgery (HSS) scores and survivorship data were analyzed.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 472 - 472
1 Dec 2013
Padgett DE Stoner K Nassif N Nawabi D Wright T Elpers M
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Introduction:

Large diameter metal on metal total hip arthroplasty (MOM THA) have shorter lengths of implantation due to increased failure caused by wear either at the articulating surface as well as the taper-trunnion interface. Taper-trunnion wear may be worse in large diameter MOM THA due the increased torque at the taper-trunnion interface. However little has been done to understand how differences in taper-trunnion geometry and trunnion engagement effects wear. The purpose of this study was to (1) measure the differences in taper geometry and trunnion engagement on the head-taper of 11/13, 12/14, and Type 1 taper designs and (2) to determine if taper geometry affects fretting, corrosion, and wear at the taper interface.

Methods:

We identified 54 MOM THA primary revision implants with head diameters greater than 36 mm from our retrieval archive. Patients' charts were queried for demographic information and pre-revision radiographs were measured for cup inclination and cup anteversion. To measure taper geometry and wear the head tapers were imaged using Redlux©. The point clouds obtained from this were analyzed in Geomagic©. Taper angles and contact length where the trunnion engaged with the female taper of the head-tapers were measured. The diameter of the taper at the most distal visual area of trunnion engagement was also measured. Best fit cones were fit to the unworn regions to approximate the pristine surface. Differences between the raw data and the unworn surface were measured and volumetric wear rates were calculated. Fretting and corrosion of the head-taper was graded using the Goldberg Scoring.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIV | Pages 25 - 25
1 Jul 2012
Kahane S Nawabi D Gillott E Briggs T
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Orthopaedic problems are common in patients with Ehlers-Danlos Syndrome (EDS). Articular hypermobility can be particularly disabling leading to instability in the appendicular skeleton. We present a case of an EDS patient presenting with knee pain and instability. It highlights important lessons to be learned when considering joint replacement in this patient group.

A 51 year old lady with EDS underwent a posterior cruciate retaining total knee replacement for pain and instability. She dislocated her knee replacement three months post-operatively after a fall. Her knee was reduced at her local emergency department causing injury to the popliteal artery. She required urgent popliteal artery repair and fasciotomies. The common peroneal nerve was also irreversibly damaged by the dislocation. She has since had one further dislocation and is now awaiting revision surgery. When considering total knee replacement (TKR) in EDS, the patient must be warned of the inferior results compared to TKR for other causes. The increased risk of complications must be explained and a more constrained TKR design considered to address the inherent joint laxity. The potential consequences of a dislocated TKR can be disastrous and therefore relocation must be performed in a controlled environment in the operating theatre.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_II | Pages 58 - 58
1 Feb 2012
Nawabi D Sinisi M Birch R
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A schwannoma is a benign nerve sheath tumour originating from schwann cells. It is the most commonly occurring peripheral nerve sheath tumour. The common sites of occurrence are the head and neck followed by the upper and lower limbs. Diagnosis is straightforward and is made clinically. Schwannomas of the tibial nerve pose a problem. The literature describes them as causes of chronic, intractable lower limb pain because their diagnosis is often delayed for several years. The main reason postulated is that a lump is not always palpable in the early phases and hence chronic cramping pain in the calf or foot is attributed to lumbosacral radiculopathy or local neuropathy.

We report the largest case series of twenty-five patients diagnosed with a tibial nerve schwannoma. Only three cases were diagnosed within a year of initial presentation. The mean time to diagnosis was eighty-six months. The most common site of pain was the sole of the foot (eighteen cases). A Tinel's sign was elicited in nineteen cases. MRI confirmed the diagnosis in all the twenty cases where it was performed. Surgical resection was performed in all cases yielding excellent results. Only one patient required further neurolysis for persisting pain.

In patients with a long history of neuropathic lower limb pain, where lumbar and pelvic lesions have been excluded, a high index of suspicion should be maintained for a peripheral nerve tumour. Delay in diagnosis is commonly due to lack of familiarity with peripheral nerve pathology and the absence of a palpable lump. The delay can result in numerous unnecessary medical and surgical interventions in this group of distressed patients. The Tinel's sign is the key to identifying a tumour of neural origin in the absence of a palpable lump. Surgical resection of the tumour remains safe and effective in providing symptomatic relief.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_III | Pages 120 - 120
1 Feb 2012
Nawabi D Mann H Lau S Wong J Andrews B Wilson A Ang S Goodier W Bucknill T
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On 7 July 2005, four bombs were detonated on the London transport system. Three of these bombs exploded almost simultaneously at 08:50h affecting the underground tube network at Aldgate, King's Cross and Edgware Road stations. The fourth bomb exploded at 09:47h on a double-decker bus in Tavistock Square. There were 54 deaths in total at the scenes and over 700 injured.

194 patients were brought to the Royal London Hospital. 167 were assessed in a designated minor injuries unit and discharged on the same day. 27 patients were admitted of whom 7 required ITU care, 1 died in theatre and 1 died post-operatively. The median Injurity Severity Score (ISS) in this group of patients was 6 (range 0-48) and the mean ISS was 12. The general pattern of injury in the critically ill patients was of mangled lower limbs and multiple, severely contaminated fragment wounds. Hepatitis B prophylaxis was administered to those patients with wounds contaminated by foreign biological material. 11 primary limb amputations were performed in 7 patients. 9 limb fasciotomies, 5 laparotomies and 1 sternotomy were carried out. 3 patients had blast lung injury. All patients who underwent primary amputations and debridement received further regular inspections in theatre. These inspections formed the majority of our theatre work. Under no circumstance was initial reconstructive surgery attempted. Delayed primary closure and split skin grafting of all wounds was completed by the end of the second week. There have been no sepsis-related deaths.

Our experience at The Royal London has allowed us to revisit the principles of blast wound management in a peacetime setting. A number of lessons were learned regarding communication and resource allocation. A multi-disciplinary approach with the successful execution of a major incident plan is the key to managing an event of this magnitude.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_II | Pages 89 - 89
1 May 2011
Nawabi D Chin K Keen R Haddad F
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Introduction: The presence of low levels of vitamin D in osteoarthritic patients has been reported as a substantial problem. We are not aware of any previous studies that have assessed the function of osteoarthritic patients undergoing joint replacement who are vitamin D deficient. This may be an important factor infiuencing preoperative function and postoperative outcome. The aim of this study was to investigate whether low vitamin D levels are associated with functional deterioration in patients with osteoarthritis of the hip undergoing total hip arthroplasty.

Methods: We measured plasma 25-hydroxyvitamin D3 (25(OH)D3) levels in 62 consecutive Caucasian patients undergoing total hip arthroplasty for osteoarthritis. The patients were divided into two groups based on whether they were vitamin D sufficient or deficient. The groups were matched for age, gender and ASA grade.

Results: The prevalence of vitamin D deficiency in our cohort of patients was comparable to recent population-based studies performed in the UK. Patients with vitamin D deficiency had lower preoperative Harris hip scores (Mann-Whitney test, p = 0.018) and were significantly less likely to attain an excellent outcome from total hip arthroplasty (Chi-square test, p = 0.038). Vitamin D levels were found to positively correlate with both preoperative and postoperative Harris hip scores.

Discussion: Our results warrant further study of vitamin D deficiency in patients undergoing joint replacement as it is a risk factor for suboptimal outcome which is relatively simple and cheap to correct.