How to manage a native stiff knee.

Knee stiffness is a widely known and worrying condition in several postoperative knees. Less is known about native stiff knee. The aim of this manuscript is to summarize the available literature on native stiff knee epidemiology, classification and treatment. In 1989 stiff knee was defined as a knee with less than 50° of total range of motion. If range of motion is <30°, it is defined as an ankylosed knee. Knee stiffness can be divided into three main types: flexion contractures, extension contractures, and combined contractures. Different risk factors have been associated to native stiff knee and grouped into modifiable or not modifiable. Furthermore, risk factors can be divided into patients' related no patients'-related. Different treatment modalities can be indicated to treat knee stiffness, including manipulation under anesthesia (MUA), arthroscopic and open surgical release. When stiffness is associated with articular disruption TKA represent an option. TKA in native stiff knee can be challenging for the surgeon. Implant's choice and knee exposure are the first steps. In some cases, additional release and extensive can be considered. A stepwise approach and careful preoperative planning are mandatory to obtain long-term satisfactory outcomes. Native stiff knee is a rare but invalidating condition. Different treatment modalities have been proposed as treatment. However, considering that it is frequently associated to sever arthritis, TKA can be an option in painful stiff knees. Nature of knee stiffness necessitates a customized approach to ensure successful management and achieve satisfying outcomes.

Incidence and pattern of periprosthetic hip fractures around the stem in different stem geometry.

BACKGROUND: The number of total hip arthroplasties (THA) is expected to increase worldwide; thus, complications are likely to increase at the same ratio. In this scenario, periprosthetic femoral fractures (PFFs) are an increasing concern. Identifying the predisposing factors is important in order to prevent as much as possible the risk of PFF in the future. PATIENTS AND METHODS: The purpose of this study was to correlate the risk of periprosthetic femoral fractures to the most common patients' comorbidities and stem geometry. We reviewed all THA for non-oncologic indications between 2004 and 2014 with a mean follow-up of six years (range, 2-12). Three thousand two hundred forty-eight patients (3593 implants) were enrolled in the study, and 45 PFF were registered during this time period. Two thousand five hundred seventy-seven implants (71%) were straight stems, and 1015 (28.3%) were anatomic stems. All X-rays were then analyzed and classified according to the modified Vancouver classification. RESULTS: Periprosthetic femoral fractures incidence was associated with anatomic stem geometry (p < 0.001, OR = 2.2), BMI (p < 0.001), and diabetes (p < 0.001, OR = 5.18). PFFs were not significantly associated with age, gender, and all the other variables. Fracture pattern was different between straight and anatomic stems. Clamshell fractures were more likely to occur in anatomic stems compared to straight stems (p < 0.005). CONCLUSIONS: Periprosthetic femoral fractures are highly associated with obesity and osteoporosis. Anatomic stems reported a higher incidence of PPF than straight stems. The typical fracture type for anatomical stems is the clamshell pattern, while straight stems are more likely affected by type B fractures.

Revision total knee arthroplasty (TKA): mid-term outcomes and bone loss/quality evaluation and treatment.

BACKGROUND: Revision total knee arthroplasty (rTKA) is a demanding procedure, with a high complication and failure rate and a high rate of bone losses and poor bone quality. Different classifications for bone losses have been proposed, but they do not consider bone quality, which may affect implant fixation. The aim of this study is to describe the outcomes of a consecutive series of rTKA. Furthermore, a modified bone loss classification will be proposed based also on bone quality. Finally, the association between radiolucent line (RLL) development and different risk factors will be evaluated. METHODS: All the patients who underwent rTKA between 2008 and 2016 in the same institution were included. rTKAs were performed by the same surgeon according to the three-step technique. Bone losses were classified according to the proposed classification, including bone quality evaluation. The Knee Scoring System (KSS), the Hospital for Special Surgery Knee Score (HSS), and the SF-12 were used for the clinical evaluation. Radiological evaluation was performed according to the Knee Society Roentgenographic Evaluation System. Different possible risk factors (i.e., gender, age, amount of bone losses) associated to RLL development were identified, and this association was evaluated using logistic regression. RESULTS: Fifty-one patients (53 knees) were included (60.8% female, average age 71.5 years). The average follow-up was 56.6 months (range 24-182). The most frequent cause of failure was aseptic loosening (41.5%). 18.9% of the cases demonstrated poor bone quality. Bone losses were treated according to the proposed algorithm. In all the cases, there was a significant improvement in all the scores (P < 0.05). The average post-operative range of motion was 110.5° (SD 10.7). At the radiological evaluation, all the implants resulted well aligned, with 15.1% of non-progressive RLL. There were 2 failures, with a cumulative survivorship of 92.1% at the last follow-up (SD 5.3%). At the logistic regression, none of the evaluated variables resulted associated to RLL development. CONCLUSION: rTKA is a demanding procedure, and adequate treatment of bone losses is mandatory to achieve good results. However, also bone quality should be taken into consideration when approaching bone losses, and the proposed classification may need surgeons after an adequate validation. LEVEL OF EVIDENCE: Level IV.

Total knee arthroplasty in the varus knee: tips and tricks.

Varus knee deformity is very common, and it can be classified according to the severity and reducibility of the deformity. Pre-operative planning is mandatory to obtain a good result. Both clinical and radiological planning should be carefully performed, particularly focused on collateral ligament deficiency. In most of the cases, a postero-stabilized implant is necessary, but in the presence of a varus thrust, a midlevel constrained (MLC) implant may be necessary. Rarely, if a severe extra-articular deformity is present, a femoral osteotomy and a high constrain implant may be necessary. In most of the cases, a standard midline approach can be performed. Soft tissue balancing is crucial, avoiding excessive releases of the medial collateral ligament (MCL). In the presence of severe deformity, more aggressive procedure such as tibial reduction osteotomy or sliding medial epicondyle osteotomy can be performed. In literature, good outcomes are reported for total knee arthroplasty (TKA) in varus deformity. In this manuscript, the available literature on TKA in varus deformity is analyzed, and the preferred surgical techniques of the authors are described.

Factors Affecting Subjective and Objective Outcomes and Return to Play in Anterior Cruciate Ligament Reconstruction: A Retrospective Cohort Study.

Purpose To analyze the prognostic factors influencing subjective and objective outcomes and return to play (RTP) after anterior cruciate ligament reconstruction (ACL-R). Methods Primary ACL-Rs using a transtibial technique performed between 2008 and 2012 were included. Data regarding patients, surgery, sports, and rehabilitation, including an on-field rehabilitation (OFR) and duration of the rehabilitation program, were collected. The International Knee Documentation Committee (IKDC) subjective and objective evaluation forms, and the Knee Injury and Osteoarthritis Outcome Score and Lysholm questionnaires were used for the assessment of subjective and objective outcomes. The Subjective Patient Outcome for Return to Sports and ACL-return to sport after injury (RSI) scores were used for RTP evaluation. Several potential predictors of outcome were tested with a univariate analysis. All the variables with p < 0.1 were retested in a logistic regression model to evaluate their association with the outcomes. Results In total, 176 cases were included with an average follow-up of 44.1 months. Of the patients, 92.2% were rated as normal or nearly normal at the IKDC evaluation. In addition, 90.1% of the patients returned to sport, with 57.6% returning to the same preinjury level. Objective outcomes were negatively influenced by late rehabilitation (odds ratio [OR] = 2.75). Performing an OFR phase during the rehabilitation was associated with better subjective outcomes (OR = 2.71). Length of rehabilitation strongly influenced the RTP rate (OR = 13.16). Conversely, higher ACL-RSI score was inversely related to RTP. Objective IKDC score was inversely related to the ACL-RSI (OR = 0.31), whereas subjective score was correlated with both the total ACL-RSI score (OR = 0.15) and the level of activity (OR = 0.20). Conclusion This study confirmed the role of rehabilitation on subjective and objective outcomes and on RTP. Particularly, the complete adherence to a rehabilitation program, including an OFR phase, resulted in better subjective outcomes and higher RTP rate. The relationship between psychological factors, measured through the ACL-RSI score, and RTP was confirmed. Level of Evidence Level III, observational study without a control group.

Patellofemoral Arthroplasty: Current Concepts and Review of the Literature.

Patellofemoral osteoarthritis (PFOA) can be associated with anterior knee pain, stiffness, and functional impairment. Some authors report that PFOA affects approximately 9% of patients older than 40 years with a greater prevalence in females. Etiology of PFOA is multifactorial and is related to the presence of abnormal stresses at the PF joint due to knee- and patient-related factors. The need for a joint preserving treatment by isolated replacement of the injured compartment of the knee led to the development of PF arthroplasty (PFA). When a correct PF replacement is performed, PFA preserves physiologic tibiofemoral joint, thus allowing patients for a rapid recovery with a high satisfaction. The outcomes for PFA are quite variable with a trend toward good to excellent results, mainly owing to the improvement in surgical techniques, patient selection, and implant design. The development of the second generation of PFA improved the outcomes, which is attributed to the different trochlear designs. Recently, encouraging results have been provided by the association of PFA and unicompartmental knee arthroplasty (UKA). In many studies, the main cause of PFA failure is progression of tibiofemoral OA. The aim of this brief review of literature is to summarize the clinical features, indications and contraindications, surgical techniques, complications, and outcomes of PFA.

Bore Disruption: An Unusual Mechanical Failure of Two Hip Hemiarthroplasties.

We report a case of two hemiarthroplasties (HAs) that underwent an unexpected mechanical failure. Two patients affected by femoral fractures were treated with an HA. At 5 and 7 years after surgery, they showed a breakage of the HA at the head-stem junction. We analyzed macroscopically and microscopically (by a scanning electron microscopy) the surfaces of the broken prostheses. In both cases, a fracture was detected starting at the joining point between the femoral head and the slot that receives the taper cone of the stem (the so-called bore), with the typical macroscopic and microscopic pattern of a fatigue fracture. The fatigue fracture resulted from repeated cycles of torsional stresses throughout the years. In literature, we did not find any other report of such HA failure.

Two-Stage Treatment of a Large Pelvic Cystic Pseudotumor in a Metal-On-Metal Total Hip Arthroplasty.

The authors report a case of a huge cystic pseudotumor, surrounding a failed metal-on-metal total hip arthroplasty (THA). The cyst surrounded the hip anteriorly, occupied part of the anterior portion of the thigh, and extended to the anterolateral aspect of the abdomen. The case was treated by a two-stage procedure. The first stage consisted of a percutaneous drainage of the fluid content of the cyst (∼1,200 mL). This procedure reduced the risk of tearing the cyst capsule spreading the liquid in the tissues surrounding the THA, and in the abdomen. Thanks to this simple procedure, the second stage treatment consisted of a relatively usual THA revision. The patient recovered completely from the treatment and returned to pain-free full activities of daily living.

Opening Wedge High Tibial Osteotomy and Anterior Cruciate Ligament Reconstruction or Revision.

High tibial osteotomy (HTO) is a valid treatment option for young active patients with medial tibiofemoral osteoarthrosis (OA) and varus deformity. Sometimes medial OA is combined with symptomatic anterior cruciate ligament (ACL) deficiency. Although isolated HTO (with possible delayed ACL reconstruction) might be indicated in the older population, young active patients may require combined HTO and ACL reconstruction. In addition, an abnormally increased tibial slope may predispose to ACL reconstruction failure and should be addressed for a successful ACL revision. The combination of HTO and ACL reconstruction produces good results, with resumption of normal daily activities, as well as recreational sports, and does not seem to increase the risk of complications compared with isolated HTO. The purpose of this Technical Note is to describe our indications, planning, and technique for opening wedge HTO fixed with a spacer plate and anatomic soft-tissue (autograft or allograft) ACL reconstruction, with proximal extracortical suspension and distal interference screw fixation.

High tibial osteotomy in varus knees: indications and limits.

Opening wedge high tibial osteotomy (OWHTO) is a surgical procedure that aims to correct the weight-bearing axis of the knee, moving the loads laterally from the medial compartment. Conventional indications for OWHTO are medial compartment osteoarthritis and varus malalignment of the knee; recently OWHTO has been used successfully in the treatment of double and triple varus. OWHTO, in contrast to closing wedge high tibial osteotomy, does not require fibular osteotomy or peroneal nerve dissection, or lead to disruption of the proximal tibiofibular joint and bone stock loss. For these reasons, interest in this procedure has grown in recent years. The aim of this study is to review the literature on OWHTO, considering indications and prognostic factors (body mass index, grade of osteoarthritis, instability, range of movement and age), outcomes at mid-term follow-up, and limits of the procedure (slope modifications, patellar height changes and difficulties in conversion to a total knee arthroplasty).

Prognostic factors for mortality after hip fracture: Operation within 48 hours is mandatory.

The aim of this study was to assess whether surgery delay and other variables are associated with an increased mortality rate after surgical treatment of hip fractures in the elderly. Patients treated for a proximal femoral fracture at our Orthopaedic Department between 2005 and 2012 were included in this study. A logistic regression was performed to evaluate the relationship between mortality rate at different follow-up times (30 days, six months and one year) and different patient or treatment variables. A total of 1448 consecutive patients with 1558 proximal femoral fractures (55 bilateral) were enrolled in this study (mean age 80.3 years, 75.8% female). The postoperative mortality rate was 4% at 30 days, 14.1% at six months, and 18.8% at one year after surgery. Logistic regression revealed an increased mortality at all the endpoints in patients affected by more than two co-morbidities (respectively OR30-day=2.003, OR6-month=1.8654 and OR1-year=1.5965). Male sex was associated with an increased six-month (OR=1.7158) and one-year (OR=1.9362) mortality. Patients aged under 74 years had a decreased mortality at all endpoints (OR30-day=0.0703, OR6-month=0.2191 and OR1-year=0.2486). In this study, the surgery delay influenced mortality at one-year follow-up: operating within 48hours was associated with a decreased mortality rate (OR=0.7341; p=0.0392). Additionally, the patients who were operated on within 72hours were specifically analysed to understand if the option of 'operating within day 3' was acceptable. In the logistic regression, operating between 48 and 72hours was not reported as a risk factor for mortality, both compared to early surgery (within 48 hours) and to late surgery (after 72hours). This study showed that age, sex and number of co-morbidities influenced both early and late mortality in patients affected by proximal hip fractures. Early surgery influenced late mortality, with a decreased risk in patients operated on within 48hours. The option of operating within day 3 is not a valid alternative.

Total knee arthroplasty and infection: how surgeons can reduce the risks.

Total joint arthroplasty (TJA) is one of the most common orthopaedic procedures. Nevertheless, several complications can lead to implant failure.Peri-prosthetic joint infections (PJI) certainly represent a significant challenge in TJA, constituting a major cause of prosthetic revision. The surgeon may have an important role in reducing the PJI rate by limiting the impact of significant risk factors associated to either the patient, the operative environment or the post-operative care.In the pre-operative period, several preventive measures may be adopted to manage reversible medical comorbidities. Other recognised pre-operative risk factors are urinary tract infections, intra-articular corticosteroid injections and nasal colonisation with Staphylococcus (S.) aureus, particularly the methicillin-resistant strain (MRSA).In the intra-operative setting, protective measures for PJI include antibiotic prophylaxis, surgical-site antisepsis and use of pre-admission chlorhexidine washing and pulsed lavage during surgery. In this setting, the use of plastic adhesive drapes and sterile stockinette, as well as using personal protection systems, do not clearly reduce the risk of infection. On the contrary, using sterile theatre light handles and splash basins as well as an increased traffic in the operating room are all associated with an increased risk for PJI.In the post-operative period, other infections causing transient bacteraemia, blood transfusion and poor wound care are considered as risk factors for PJI. Cite this article: Ratto N, Arrigoni C, Rosso F, Bruzzone M, Dettoni F, Bonasia DE, Rossi R. Total knee arthroplasty and infection: how surgeons can reduce the risks. EFORT Open Rev 2016;1: 339-344 DOI: 10.1302/2058-5241.1.000032.

Use of tranexamic acid in total knee arthroplasty.

PURPOSE: different strategies have been developed to reduce blood loss in total knee arthroplasty (TKA). The efficacy of both systemic and local tranexamic acid (TXA) administration is demonstrated in the literature. The aim of the present study was to compare the efficacy of systemic, local and combined (systemic + local) administration of TXA in reducing blood loss after TKA. METHODS: we enrolled all patients submitted to a primary TKA in our department between November 2014 and August 2015. They were divided into three groups corresponding to the method of TXA administration used: intravenous (IV), intra-articular (IA), and a combination of the two. Demographic data, as well as preoperative hemoglobin and platelet levels, were collected. The primary outcome was the maximum hemoglobin loss, while the secondary outcomes were the amount of blood in the drain (cc/hour) and the rate of transfusions; postoperative pain was also assessed. Student's t-test or a χ2 test was used to evaluate between-group differences, using p<0.05 as the cut-off for statistically significant differences. RESULTS: the sample comprised 34 patients: IV, 10 cases; IA, 15 cases, and combined (IV + IA), 9 cases. The average age of the patients was 71.1±6.4 years. No significant differences in the outcome measures were found between the groups, with the exception of a significantly lower maximum hemoglobin loss in the combined versus the IV group (p=0.02). There were no differences between the groups in the amount of blood in the drain or the rate of transfusions. CONCLUSIONS: the data from this preliminary study, as well as data from the literature, confirm that TXA administration is safe and effective in reducing total blood loss in TKA, and no administration protocol seems to be superior to the others. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Painful knee arthroplasty: current practice.

Primary total knee arthroplasty is the treatment for end-stage arthritis of the knee; in the last years, it is becoming more common and reliable, due to technical and implant improvement. With larger implant rates, the overall complications will increase and pain is the most common sign of implant failure. Pain can be related to a lot of different clinical findings, and the surgeon has to be aware of the various etiologies that can lead to failure. Pain does not always mean revision, and the patient has to be fully evaluated to have a correct diagnosis; if surgery is performed for the wrong reason, this will surely lead to a failure. In this paper, the authors revised the more common causes of failure that can have a painful onset proposing an approach for diagnosis and treatment.

The role of the popliteus tendon in total knee arthroplasty: a cadaveric study: SIGASCOT Best Paper Award Finalist 2014.

PURPOSE: this study was conducted to investigate the influence of the popliteus tendon (PT) on the static stability of total knee arthroplasty (TKA). METHODS: twenty knees were used. In 10 right knees, a cruciate-retaining (CR) TKA trial prosthesis was implanted; in the other ten knees (left knees), the posterior cruciate ligament was cut and a posterior substitution (PS) TKA trial prosthesis was implanted. Lamina spreaders were set at 100 N of tension, one on the medial and one on the lateral articular space. Gaps were then measured with a caliper before and after PT sectioning. RESULTS: the correlation between femoral dimensions and popliteus insertion distance from articular surfaces was measured with the Pearson correlation index and considered significant. In the CR-TKA group, medial and lateral gap measurements showed a significant increase after PT sectioning both in flexion and in extension. In the PS-TKA group, lateral gap measurements showed a significant increase after PT sectioning both in flexion and in extension, while the medial gap measurements increased significantly only in flexion. CONCLUSIONS: PT sectioning destabilized both the lateral and the medial aspects of the knee. A greater effect was observed in the lateral compartment. The most statistically reliable effect was observed with the knee in flexion. In addition, we observed that preserving the PCL does not prevent lateral gap opening after PT sectioning. CLINICAL RELEVANCE: PT should always be preserved when performing a TKA, because its resection can affect gap balancing, in flexion and in extension. TYPE OF STUDY: controlled laboratory study.

Patellar tendon: From tendinopathy to rupture.

Patellar tendinopathy is very common in patients complaining of anterior knee pain. Its aetiology is still unclear, but neovascularisation seems to play a role. Different treatments have been proposed overtime, from rehabilitation to platelet-rich-plasma injections, but there is no agreement on the best treatment protocol. The final stage of patellar tendinopathy is patellar tendon rupture. In these cases surgical treatment is often required. The aim of this literature review is to focus on the aetiology, diagnosis, and treatment of both patellar tendinopathy and rupture. We report the conservative treatments proposed for patellar tendinopathy and the surgical techniques described for its rupture.

Validation and cross cultural adaptation of the Italian version of the Harris Hip Score.

INTRODUCTION: The Harris Hip Score (HHS) is one of the most widely used health related quality of life (HRQOL) measures for the assessment of hip pathology: in spite of this, a validation study, and an official Italian version have not been provided yet. The aim of this study was to create an Italian valid and reliable version of the HHS. MATERIALS AND METHODS: The score was translated and modified in Italian; then 103 patients with different hip pathologies were evaluated using this HHS version and also with the WOMAC and the SF-12 questionnaires. Content, construct and criterion validities were tested, such as interobserver reliability, test-retest reliability and internal consistency. RESULTS: Cross-cultural adaptation was easy, and only minor adaptation was required in the translation process. Construct and criterion validity of the HHS Italian Version were confirmed by satisfactory values of Spearman's Rho for correlation between specific domains of HHS and Womac and SF12 scores. Interobserver and test-retest reliabilities obtained values of 0.996 and 0.975 respectively; Cronbach's alpha for internal consistency was 0.816. DISCUSSION: Statistical and clinical analysis showed that HHS is highly valid and reliable in this new Italian version.

Bone marrow derived stem cells in joint and bone diseases: a concise review.

Stem cells have huge applications in the field of tissue engineering and regenerative medicine. Their use is currently not restricted to the life-threatening diseases but also extended to disorders involving the structural tissues, which may not jeopardize the patients' life, but certainly influence their quality of life. In fact, a particularly popular line of research is represented by the regeneration of bone and cartilage tissues to treat various orthopaedic disorders. Most of these pioneering research lines that aim to create new treatments for diseases that currently have limited therapies are still in the bench of the researchers. However, in recent years, several clinical trials have been started with satisfactory and encouraging results. This article aims to review the concept of stem cells and their characterization in terms of site of residence, differentiation potential and therapeutic prospective. In fact, while only the bone marrow was initially considered as a "reservoir" of this cell population, later, adipose tissue and muscle tissue have provided a considerable amount of cells available for multiple differentiation. In reality, recently, the so-called "stem cell niche" was identified as the perivascular space, recognizing these cells as almost ubiquitous. In the field of bone and joint diseases, their potential to differentiate into multiple cell lines makes their application ideally immediate through three main modalities: (1) cells selected by withdrawal from bone marrow, subsequent culture in the laboratory, and ultimately transplant at the site of injury; (2) bone marrow aspirate, concentrated and directly implanted into the injury site; (3) systemic mobilization of stem cells and other bone marrow precursors by the use of growth factors. The use of this cell population in joint and bone disease will be addressed and discussed, analysing both the clinical outcomes but also the basic research background, which has justified their use for the treatment of bone, cartilage and meniscus tissues.

Medial opening wedge high tibial osteotomy for medial compartment overload/arthritis in the varus knee: prognostic factors.

BACKGROUND: Medial opening wedge high tibial osteotomy (OWHTO) is a widely accepted procedure for the treatment of medial compartment arthritis of the knee. Compared with closing wedge HTO, however, the outcomes of OWHTO reported in the literature are incomplete. PURPOSE: To identify the positive and negative prognostic factors related to the outcomes of OWHTO through an evaluation of midterm study results and survivorship analysis. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: From January 2001 to December 2009, a total of 141 consecutive OWHTOs were performed in 123 patients. Only patients with symptomatic medial knee overload/arthritis were included. The patients were evaluated preoperatively and at every follow-up visit with (1) the Knee Society score, (2) the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, (3) another self-evaluation scale, (4) long-leg radiographs, and (5) plain radiographs. Preoperative, intraoperative, and postoperative variables were investigated to find an association with the outcomes. RESULTS: Of the 123 patients, 15 were lost to follow-up, and 24 were excluded from the study, leaving 84 patients (99 OWHTOs) for the present study. The mean age of the patients at the time of surgery was 54.5 ± 9.2 years. The mean follow-up was 51.5 ± 23.8 months. The Knee Society and WOMAC scores significantly improved after surgery (P < .001). The variables significantly related to a poor outcome were (1) age >56 years (P = .008) and (2) postoperative knee flexion <120° (P < .001); the variables significantly related to a good outcome were (1) Ahlbäck grade 0 arthritis of the medial compartment (P < .001) and (2) excellent preoperative Knee Society score (P < .001). The Kaplan-Meier analysis showed a survival rate of 98.7% at 5 years and 75.9% at 7.5 years. CONCLUSION: With correct indications, OWHTO is a reliable procedure for medial knee arthritis/overload. The outcomes reported are similar to those from other studies, although the variables related to outcomes are slightly different.

A future in our past: the umbilical cord for orthopaedic tissue engineering.

The umbilical cord (UC) has recently been added to the list of potential cell sources for tissue engineering and regenerative medicine purposes. Although the UC is usually discarded after delivery, UC storage in special tissue banks is becoming an increasingly common procedure. Indeed, the capacity of UC cells to be directed toward different phenotypes makes this tissue an ideal cell source for regenerative medicine in orthopedics and in other fields. In this paper, these issues are presented and discussed, together with the potential of this cell source for allogeneic use. This article also looks at the anatomy of the UC from both the macroscopic and the cellular perspective and considers its extraordinary potential for research and clinical applications.