Total Humeral Endoprosthetic Reconstruction: A Systematic Review.

BACKGROUND: Total humeral endoprosthetic reconstruction (THER) is a rare reconstruction option for limb salvage surgery for large humeral neoplasms or bone destruction. MATERIALS AND METHODS: Because of the limited data and need for this procedure, we reviewed the literature surrounding THER and assessed functionality, complications, and revisions using the PubMed, Embase, Ovid, and Scopus databases. RESULTS: Among 29 articles and 175 patients, the most common indication was neoplasm (n=25, 86%), mean follow-up was 61.98 months (SD=55.25 months), and mean Musculoskeletal Tumor Society score was 73.64% (SD=10.69%). Reported complications included 26 (23%) revisions in 7 studies, 35 (36%) cases of shoulder instability in 7 studies, and 13 (13.54%) cases of deep infection in 4 studies. CONCLUSION: THER should be considered with a thorough knowledge of outcomes and potential complications to guide patient and clinician expectations. [Orthopedics. 2024;47(3):e106-e113.].

Degraded RNA from Human Anterior Cruciate Ligaments Yields Valid Gene Expression Profiles.

Correlating gene expression patterns with biomechanical properties of connective tissues provides insights into the molecular processes underlying the tissue growth and repair. Cadaveric specimens such as human knees are widely considered suitable for biomechanical studies, but their usefulness for gene expression experiments is potentially limited by the unavoidable, nuclease-mediated degradation of RNA. Here, we tested whether valid gene expression profiles can be obtained using degraded RNA from human anterior cruciate ligaments (ACLs). Human ACL RNA (N = 6) degraded in vitro by limited ribonuclease digestion resemble highly degraded RNA isolated from cadaveric tissue. PCR threshold cycle (Ct) values for 90 transcripts (84 extracellular matrix, 6 housekeeping) in degraded RNAs variably ranged higher than values obtained from their corresponding non-degraded RNAs, reflecting both the expected loss of target templates in the degraded preparations as well as differences in the extent of degradation. Relative Ct values obtained for mRNAs in degraded preparations strongly correlated with the corresponding levels in non-degraded RNA, both for each ACL as well as for the pooled results from all six ACLs. Nuclease-mediated degradation produced similar, strongly correlated losses of housekeeping and non-housekeeping gene mRNAs. RNA degraded in situ yielded comparable results, confirming that in vitro digestion effectively modeled degradation by endogenous ribonucleases in frozen and thawed ACL. We conclude that, contrary to conventional wisdom, PCR-based expression analyses can yield valid mRNA profiles even from RNA preparations that are more than 90% degraded, such as those obtained from connective tissues subjected to biomechanical studies. Furthermore, legitimate quantitative comparisons between variably degraded tissues can be made by normalizing data to appropriate housekeeping transcripts.

Pathological analysis of periprosthetic soft tissue and modes of failure in revision total joint arthroplasty patients.

OBJECTIVES: Implant failure leading to revision total joint arthroplasty can occur through a variety of different mechanisms which are typically associated with a soft tissue response adjacent to the implant that provide insight into the underlying etiology of implant failure. The objective of this study was to elucidate mechanisms of implant failure as they relate to histological classification and findings of adjacent periprosthetic tissue. METHODS: Histological analysis of soft tissue adjacent to the implant was performed in 99 patients with an average age of 64 years old and grouped into four categories based on the study conducted by Morawietz et al.:Type I (N = 47)Wear particle induced typeType II (N = 7)Infectious typeType III (N = 19)Combined type I and IIType IV (N = 26)Indeterminant typeModes of failure were categorized into five groupings based on the study conducted by Callies et al.: Instability (N = 35), Aseptic Loosening (N = 24), Hardware and/or Mechanical Failure (N = 15), Septic (N = 13), and Other failures (N = 12). We calculated odds ratios and conducted regression analysis to assess the relationship between modes of failure and histological findings as well as modes of failure and comorbidities. RESULTS: Hardware/mechanical failure was independently correlated with histological findings of anucleate protein debris, histiocytes, Staphylococcus epidermidis, and synovitis. Furthermore, hardware/mechanical failure was independently correlated with osteosarcoma as a co-morbidity. Septic failure was associated with histological findings of Enterococcus, granulation tissue, and tissue necrosis as well as comorbidities of Crohn's disease, deep venous thrombosis, lung disease, and rheumatoid arthritis. Infection was 5.8 times more likely to be associated with Type II histology. Aseptic loosening was associated with histologic findings of synovitis. CONCLUSION: Our findings support the existing literature on periprosthetic tissue analysis in revision total joint arthroplasty which may improve surgeon understanding of the patholophysiological mechanisms that contribute to implant failure and revision surgery.

Diagnosis and management of primary malignant tumors in the upper extremity.

Bone and soft tissue sarcomas of the upper extremity are relatively uncommon. In many cases, they are discovered incidentally during evaluation of traumatic injuries or common ailments such as rotator cuff tendonitis or tennis elbow. Thus, it is important for all orthopedic surgeons to understand the differential diagnosis, workup, and treatment for upper extremity lesions. An appreciation of the clinical and radiographic features of primary malignant lesions aids in identifying patients that need referral to an orthopedic oncologist and a multidisciplinary team.

A Unique Case of Extra-articular Extravasation of Metal Into the Lower Leg Resulting From Oxidized Zirconium Wear Particles From Total Knee Arthroplasty.

With an increasing number of joint replacements and the evolution of orthopaedic implants and hardware, there is increased occurrence and awareness of metal-related sensitivity. This has resulted in the development of devices using a variety of different materials to coat the implant. One popular option is to cover the metallic surface with a ceramic. One commercially available ceramic-coated prosthesis is coated with oxidized zirconium, with the trade name Oxinium. Although pseudotumor and metallosis resulting from ceramic joint arthroplasty implants have been documented, there is limited information on the occurrence of metallosis resulting from ceramic-coated knee implants. The purpose of this case report is to discuss a potential differential diagnosis for lower leg mass after total knee arthroplasty and to present a novel case of catastrophic failure of an Oxinium-coated total knee prosthesis (Smith and Nephew) that resulted in metallosis with extra-articular extravasation along the extensor digitorum longus tendon.

Spontaneous 180-Degree Rotatory Dislocation of Rotating-Platform Total Knee Arthroplasty.

Rotating-bearing total knee arthroplasty has been theorized to have some advantages in the kinematics and wear characteristics of total knee arthroplasty. A rare complication of rotating-bearing total knee arthroplasty is rotary dislocation, spinout, of the polyethylene component. When these dislocations occur, they typically result in a 90-degree dislocation in respect to the axial axis of the knee. This case is unique in that it presents a complete 180-degree polyethylene dislocation without trauma.

Do local antibiotics reduce periprosthetic joint infections? A retrospective review of 744 cases.

Periprosthetic joint infections (PJI) are uncommon but not rare and have significant morbidity and financial implications. Local antibiotics have been used successfully in other areas of orthopedics to reduce postoperative infections, but this method has not been proven in total joint arthroplasty (TJA). Beginning January 1, 2014, our primary investigators began using surgical site lavage with providone-iodine solution and administering 2 g of vancomcyin powder in the surgical wound prior to capsule closure for all primary and revision total hip and knee arthroplasties. We performed a retrospective chart review of patients two years prior to this date and two years after to compare occurrence of PJI. The groups were broken down into patients who received local antibiotics versus those who did not. The groups were further broken down by type of surgery performed; primary or revision total hip or knee arthroplasty. Administration of local antibiotics was preventative for PJI only in the primary total knee arthroplasty group (aOR = 0.28, 0.09-0.89). Administration of local antibiotics trended towards a preventative effect for PJI in the other groups but was not statistically significant. Patients receiving local antibiotics had similar blood urea nitrogen and creatinine levels postoperatively compared to the no antibiotics group indicating minimal systemic effects of local vancomycin powder. While the use of local antibiotics may prevent PJI, more data is required especially in the revision arthroplasty groups.

Osteofibrous Dysplasia-like Adamantinoma of the Tibia in a 15-Year-Old Girl.

Osteofibrous dysplasia and adamantinoma are rare lesions of primary benign and malignant bone tumors with an incidence of less than 1%. These lesions arise primarily in long bones with a predilection for the tibia and fibula. Osteofibrous dysplasia is a benign fibro-osseous lesion typically found in children younger than 10 years. Adamantinomas, however, are highly malignant and invasive tumors found predominantly in adult men, with an average age of diagnosis between 20 and 50 years. Debate continues on whether osteofibrous dysplasia and adamantinoma occupy the same disease spectrum. Within the spectrum of pathology lies a rare benign lesion known as osteofibrous dysplasia-like adamantinoma. This intermediate form has the potential to spontaneously regress or transform into a malignant adamantinoma. We report a rare case of an osteofibrous dysplasia-like adamantinoma of the tibia in a 15-year-old girl. The patient was followed with regular 3- to 6-month follow-ups. The lesion remained stable and showed no progression over 2 years. Given the benign nature of osteofibrous dysplasia and osteofibrous dysplasia-like adamantinoma and the malignant nature of adamantinoma, correctly diagnosing the lesion has significant treatment implications. This case report highlights the rarity of this intermediate form and its potential to remain stable. Such lesions can be observed with frequent follow-ups without the need for surgical intervention.

Influence of a platelet concentrate on prosthetic bone ingrowth in a rabbit model.

Recent studies have shown that an increase in bone ingrowth by addition of osteogenic growth factors can reduce micro motion and gross implant motion and contribute to joint implant stability through osseointegration. Platelet-rich plasma (PRP) has the potential to provide growth factors that may be conducive to osteointegration at the bone-implant interface. This study analyzed the influence of PRP on bone ingrowth upon a beaded metal implant in distal femurs of 22 rabbits. Rabbit limbs were randomly assigned to receive an implant plus PRP or plain implant. Half of the specimens were randomly assigned to a 2-week group (n = 20) or a 5-week group (n = 20). Histologic and histomorphometric comparison between implant alone and implant plus PRP, at 2 and 5 weeks, was performed. In both the 2- and 5-week comparisons, there was no statistical difference (p > .05) in bone ingrowth between the control and PRP group, despite a slight increase in trabecular bone growth in PRP groups. This study suggests that PRP is not a major contributing factor to bone ingrowth at the bone-implant interface. This supports growing evidence in the literature that PRP can lead to variable bone growth stimulation in vivo.

Osteochondral autograft transplantation in the porcine knee.

BACKGROUND: Knee articular cartilage defects are not an uncommon problem. Because articular cartilage is limited in its ability to heal, these defects are difficult to manage. HYPOTHESIS: Osteochondral autografts will provide less of a cavitary defect and more viable hyaline articular cartilage than will control knees. STUDY DESIGN: Controlled laboratory study. METHODS: Osteochondral autografts were grossly and microscopically evaluated in the porcine knee and compared with a control at 6 weeks, 3 months, and 6 months. In 18 porcine specimens, a 1-stage surgical procedure was performed to harvest an osteochondral graft from a nonweightbearing articular cartilage surface, and the graft was transplanted into a defect created in the weight-bearing region of the medial femoral condyle. In the opposite control knee, a similar defect was created in the medial femoral condyle; an osteochondral transplant was not performed. Six pigs each were sacrificed at 6 weeks, 3 months, and 6 months. RESULTS: Gross inspection of the control knees showed a cavitary defect. The defect grossly decreased in size with fibrous ingrowth seen on microscopic analysis. An increasing amount of fibrous tissue and fibrocartilage was present at the 3 time periods. Gross inspection of the graft knee showed a healed osteochondral plug with no obvious displacement, cavitary defects, or surrounding necrotic tissue at each time interval. Microscopic analysis revealed the graft knee contained viable hyaline cartilage and healed viable subchondral bone. At all time intervals, 75% to 100% of the hyaline cartilage was viable in all specimens. In 6-month specimens, bridging cartilage at the autograft-host junction was incomplete in 50%, partial in 33%, and complete in 17%. CONCLUSION: Osteochondral autografts in the porcine knee resulted in viable hyaline cartilage for up to 6 months; there was inconsistent bridging hyaline cartilage at the periphery. Grafts appeared to heal into existing subchondral bone without displacement or evidence of necrosis. CLINICAL RELEVANCE: This type of osteochondral transplant can be used as a reliable reconstructive alternative for osteochondral defects.

Case reports: malignant transformation of aneurysmal bone cysts.

An aneurysmal bone cyst is an uncommon benign primary bone tumor. Careful intralesional curettage through a wide cortical window in addition to cauterization with or without adjuvant therapy (phenol or hydrogen peroxide) and bone grafting or cementation is the preferred surgical treatment. Adjuvant or primary radiation of an aneurysmal bone cyst rarely is used because of its association with malignant transformation of the lesion. Several cases of late malignant transformation of primary aneurysmal bone cysts without adjuvant radiation have been reported. We provide additional documentation of two primary aneurysmal bone cysts treated surgically with careful intralesional curettage through a wide cortical window and allograft bone grafting without adjuvant radiation. At 5.5 years and 12 years after treatment, a telangiectatic osteosarcoma and a fibroblastic osteosarcoma, respectively, were identified in the site of the original lesions. Not only should aneurysmal bone cysts be evaluated carefully through histologic examination at presentation, patients also should be counseled regarding possible recurrence and the need for routine followups, especially if symptoms change.