Pradeep Kodali

Anterior knee pain in the young athlete: diagnosis and treatment.

The underlying etiology of anterior knee pain has been extensively studied. Despite many possible causes, often times the diagnosis is elusive. The most common causes in the young athlete are osteosynchondroses, patellar peritendinitis and tendinosis, synovial impingement, malalignment, and patellar instability. Less common causes are osteochondritis dissecans and tumors. It is always important to rule out underlying hip pathology and infections. When a diagnosis cannot be established, the patient is usually labeled as having idiopathic anterior knee pain. A careful history and physical examination can point to the correct diagnosis in the majority of cases. For most of these conditions, treatment is typically nonoperative with surgery reserved for refractory pain for an established diagnosis.

Computer-assisted surgery for anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopedic procedures. Revision rates are as high as 40% with malpositioned tunnels as a chief contributor. Computer-assisted orthopedic surgery or navigation for ACL reconstruction has been introduced to help decrease the revision rate. We review the role of computer navigation in improving the accuracy of tunnel placement, assessing kinematics of the knee, and in training surgeons to correctly perform ACL reconstructions. We report on our experience with navigated ACL reconstruction and describe the kinematic evaluation of a series of patients who underwent the procedure.

Early tissue response to citric acid-based micro- and nanocomposites

Composites based on calcium phosphates and biodegradable polymers are desirable for orthopedic applications because of their potential to mimic bone. Herein, we describe the fabrication, characterization, and in vivo response of novel citric acid-based microcomposites and nanocomposites. Poly(1,8-octanediol-co-citrate) (POC) was mixed with increasing amounts of hydroxyapatite (HA) nanoparticles or microparticles (up to 60 wt %), and the morphology and mechanical properties of the resulting composites were assessed. To investigate tissue response, nanocomposites, microcomposites, POC, and poly(L-lactide) were implanted in osteochondral defects in rabbits and harvested at 6 weeks for histological evaluation. Scanning electron microscopy confirmed increased surface roughness of microcomposites relative to nanocomposites. The mechanical properties of both types of composites increased with increasing amounts of HA (8-328 MPa), although nanocomposites with 60 wt % HA displayed the highest strength and stiffness. Based on tissue-implant interfacial assessments, all implants integrated well with the surrounding bone and cartilage with no evidence of inflammation. Both nanocomposites and microcomposites supported bone remodeling; however, nanocomposites induced more trabecular bone formation at the tissue-implant interface. The mechanical properties of citric acid-based composites are within the range of human trabecular bone (1-1524 MPa, 211 ± 78 MPa mean modulus), and tissue response was dependent on the size and content of HA, providing new perspectives of design and fabrication criteria for orthopedic devices such as interference screws and fixation pins.

Imaging instability in the athlete: the right modality for the right diagnosis.

The imaging evaluation of an athlete with glenohumeral instability encompasses multiple modalities, including radiography, CT, and MRI. There remains an overall lack of agreement and consistency among the orthopedic community regarding techniques used to quantify glenohumeral bone loss. When a high level of clinical suspicion remains, advanced imaging techniques are strongly recommended to ensure reliable and accurate assessment of defect size and location.

Partial Resurfacing for Humeral Head Defects Associated With Recurrent Shoulder Instability

Recurrent traumatic shoulder instability is a complex clinical entity that commonly affects young, active patients. Humeral head defects are frequently associated with this condition, but specific treatment to stabilize the shoulder is rarely needed. Management options for defects of the humeral head that do necessitate treatment carry various risks and disadvantages, including the need for bone or soft tissue healing, complications related to hardware, and loss of motion. Partial prosthetic resurfacing has been reported as a treatment option. The current study retrospectively reviewed a cohort of patients with recurrent or locked anterior and posterior instability who underwent partial prosthetic humeral head resurfacing for significant Hill-Sachs and reverse Hill-Sachs lesions. At an average of 36.4 months after the index procedure, 16 patients were contacted by mail and telephone. Of the study group, 13 patients underwent partial resurfacing for anterior instability and 3 patients underwent partial re-surfacing for posterior instability. No patient had a repeat dislocation. In addition, 77% of patients in the anterior instability cohort and all of the patients in the posterior instability cohort returned to their full preinjury activity level. For the anterior instability cohort, significant improvements from preoperatively to final follow-up occurred for mean Musculoskeletal Review of System score (4.54, P<.0001) and Short Form-12 physical component score (9.52, P=.002). For the combined cohort, the Penn Shoulder Score improved by 36.4 points (P=.059). This study showed the effectiveness of partial humeral head resurfacing for preventing redislocation for patients with significant Hill-Sachs and reverse Hill-Sachs lesions. [Orthopedics. 2017; 40(6):e996-e1003.].

Focal Resurfacing of Humeral-Head Defects

Traumatic shoulder instability is extremely common in athletes. It is usually due to abnormal abduction, external rotation, and extension force on the shoulder, causing it to exceed normal limits of glenohumeral motion and resulting in anterior dislocation. A characteristic anteroinferior capsulolabral injury occurs and has been deemed the essential lesion in anterior shoulder instability [1]–[3]. A posterosuperior humeral-head defect (Hill-Sachs lesion) is noted in 93% of cases [4]. This bone defect, if large enough, may contribute to failed soft tissue stabilization that occurs in 8–18% of patients [4]–[6]. Large defects lead to an articular arc mismatch that, at lesser degrees of external rotation, will engage with the anteroinferior glenoid, causing instability [7]. Treatment typically entails a combined procedure to address the soft tissue injury and bone defect. For large Hill-Sachs lesions, surgical options include nonanatomic techniques, such as the remplissage procedure [4], [8], or anatomic techniques. Purchase et al. [8] used an arthroscopic remplissage technique and had only a 7% chance of recurrent instability. Anatomic techniques include either matched humeral-head allograft or resurfacing arthroplasty with HemiCAP© (Arthrosurface, Franklin, MA, USA) [9]. Allograft transplantation for Hill-Sachs lesions has been described and yields good outcomes in most case reports [10]–[12].

Erratum to “A citric acid-based hydroxyapatite composite for orthopedic implants”

We describe a novel approach to process bioceramic microparticles and poly(diol citrates) into bioceramic-elastomer composites for potential use in orthopedic surgery. The composite consists of the biodegradable elastomer poly(1,8-octanediol-citrate) (POC) and the bioceramic hydroxyapatite (HA). The objective of this work was to characterize POC-HA composites and assess the feasibility of fabricating tissue fixation devices using machining and molding techniques. The mechanical properties of POC-HA composites with HA (40, 50, 60, 65wt.%) were within the range of values reported for tissue fixation devices (for POC-HA 65wt.%, S(b)=41.4+/-3.1, E(b)=501.7+/-40.3, S(c)=74.6+/-9.0, E(c)=448.8+/-27.0, S(t)=9.7+/-2.3, E(t)=334.8+/-73.5, S(s)=27.7+/-2.4, T(s)=27.3+/-4.9, all values in MPa). At 20 weeks, the weight loss of POC-HA composites ranged between 8 and 12wt.%, with 65wt.% HA composites degrading the slowest. Exposure of POC-HA to simulated body fluid resulted in extensive mineralization in the form of calcium phosphate with Ca/P of 1.5-1.7 similar to bone. POC-HA supported osteoblast adhesion in vitro and histology results from POC-HA samples that were implanted in rabbit knees for 6 weeks suggest that the composite is biocompatible. Synthesis of POC-HA is easy and inexpensive, does not involve harsh solvents or initiators, and the mechanical properties of POC-HA with 65wt.% HA are suitable for the fabrication of potentially osteoconductive bone screws.

Erratum to “A citric acid-based hydroxyapatite composite for orthopedic implants”: [Biomaterials 27 (2006) 5845–5854]

We describe a novel approach to process bioceramic microparticles and poly(diol citrates) into bioceramic-elastomer composites for potential use in orthopedic surgery. The composite consists of the biodegradable elastomer poly(1,8-octanediol-citrate) (POC) and the bioceramic hydroxyapatite (HA). The objective of this work was to characterize POC-HA composites and assess the feasibility of fabricating tissue fixation devices using machining and molding techniques. The mechanical properties of POC-HA composites with HA (40, 50, 60, 65wt.%) were within the range of values reported for tissue fixation devices (for POC-HA 65wt.%, S(b)=41.4+/-3.1, E(b)=501.7+/-40.3, S(c)=74.6+/-9.0, E(c)=448.8+/-27.0, S(t)=9.7+/-2.3, E(t)=334.8+/-73.5, S(s)=27.7+/-2.4, T(s)=27.3+/-4.9, all values in MPa). At 20 weeks, the weight loss of POC-HA composites ranged between 8 and 12wt.%, with 65wt.% HA composites degrading the slowest. Exposure of POC-HA to simulated body fluid resulted in extensive mineralization in the form of calcium phosphate with Ca/P of 1.5-1.7 similar to bone. POC-HA supported osteoblast adhesion in vitro and histology results from POC-HA samples that were implanted in rabbit knees for 6 weeks suggest that the composite is biocompatible. Synthesis of POC-HA is easy and inexpensive, does not involve harsh solvents or initiators, and the mechanical properties of POC-HA with 65wt.% HA are suitable for the fabrication of potentially osteoconductive bone screws.

Erratum to "A citric acid-based hydroxyapatite composite for orthopedic implants". [Biomaterials 27 (2006) 5845-5854] (DOI: 10.1016/j.biomaterials.2006.07.042)

We describe a novel approach to process bioceramic microparticles and poly(diol citrates) into bioceramic-elastomer composites for potential use in orthopedic surgery. The composite consists of the biodegradable elastomer poly(1,8-octanediol-citrate) (POC) and the bioceramic hydroxyapatite (HA). The objective of this work was to characterize POC-HA composites and assess the feasibility of fabricating tissue fixation devices using machining and molding techniques. The mechanical properties of POC-HA composites with HA (40, 50, 60, 65wt.%) were within the range of values reported for tissue fixation devices (for POC-HA 65wt.%, S(b)=41.4+/-3.1, E(b)=501.7+/-40.3, S(c)=74.6+/-9.0, E(c)=448.8+/-27.0, S(t)=9.7+/-2.3, E(t)=334.8+/-73.5, S(s)=27.7+/-2.4, T(s)=27.3+/-4.9, all values in MPa). At 20 weeks, the weight loss of POC-HA composites ranged between 8 and 12wt.%, with 65wt.% HA composites degrading the slowest. Exposure of POC-HA to simulated body fluid resulted in extensive mineralization in the form of calcium phosphate with Ca/P of 1.5-1.7 similar to bone. POC-HA supported osteoblast adhesion in vitro and histology results from POC-HA samples that were implanted in rabbit knees for 6 weeks suggest that the composite is biocompatible. Synthesis of POC-HA is easy and inexpensive, does not involve harsh solvents or initiators, and the mechanical properties of POC-HA with 65wt.% HA are suitable for the fabrication of potentially osteoconductive bone screws.