Frederick Clinton Kidner

Frederick Clinton Kidner, MD, FACS (April 13, 1879 – November 9, 1950) was an influential American orthopaedic surgeon whose clinical and operative innovations fundamentally advanced reconstructive foot and ankle surgery and pediatric orthopaedics, celebrated for conceiving the eponymous Kidner procedure (excision of the accessory navicular with plantar transposition of the posterior tibial tendon), elucidating the functional biomechanics of the prehallux in pes planus, establishing the natural history and conservative management of Köhler’s disease of the tarsal scaphoid, and formulating foundational conservative algorithms for low back pain and sciatica.

1. The Shoulders of Giants: Historical Context & Significance

Modern reconstructive foot and ankle surgery and pediatric orthopaedics rest securely upon anatomical and biomechanical principles established during the transformative first half of the twentieth century. Whenever an orthopaedic surgeon addresses a painful medial midfoot prominence in an adolescent, isolates an anomalous secondary ossification center of the tarsal scaphoid, and mobilizes the posterior tibial tendon into a plantar navicular trough to restore dynamic medial longitudinal arch suspension, they stand directly upon the intellectual shoulders of Frederick Clinton Kidner. Kidner bridged the formative transition between descriptive musculoskeletal pathology and physiologic, motion-preserving reconstruction.

“If I have seen further, it is by standing on the shoulders of giants.”

Sir Isaac Newton (1675) / Bernard of Chartres

During the opening decades of the twentieth century, clinical management of symptomatic flatfoot (pes planovalgus) was dominated by empirical dogma, rigid external steel arch supports, or aggressive, joint-sacrificing arthrodeses. Pathologists and anatomists had long recognized the sporadic presence of an accessory ossicle at the medial aspect of the tarsal scaphoid (termed the prehallux or os tibiale externum), but its mechanical significance remained misunderstood or dismissed as an incidental developmental quirk. Kidner recognized that this anatomical variant was an active driver of progressive medial arch collapse. By demonstrating that the accessory navicular altered the line of pull of the posterior tibial muscle (transforming a vital dynamic arch suspender into an ineffective horizontal adductor), Kidner devised an elegant operative solution that addressed the root mechanical fault while preserving articular motion across the midfoot joints.

Beyond his eponymous foot reconstruction, Kidner was an exemplary surgical scholar of the interwar era whose clinical investigations consistently favored biological restoration over unnecessary operative destruction. Trained in the historic Boston orthopaedic crucible of Massachusetts General Hospital and Boston Children’s Hospital under Edward Hickling Bradford and Joel E. Goldthwait, and seasoned through frontline military service alongside Sir Robert Jones in World War I, Kidner brought rigorous scientific discipline to Detroit. His landmark 1924 study of 104 children with Köhler’s disease demonstrated that ischemic necrosis of the tarsal navicular undergoes complete spontaneous reossification under protected immobilization, sparing generations of pediatric patients from disfiguring exploratory surgery. Later, as surgical enthusiasm for spinal laminectomies surged following the initial descriptions of herniated intervertebral discs, Kidner advocated disciplined conservative pathways for sciatica and low back pain, establishing principles of physical rehabilitation that remain central to contemporary spine care.

2. Early Life, Formative Education & Career Milestones

Education and Formative Surgical Training

Frederick Clinton Kidner was born on April 13, 1879, in Boston, Massachusetts, the son of the Reverend Reuben Kidner and Katherine Clinton Kidner. Raised in an intellectually rigorous household steeped in New England traditions of scholarship and civic responsibility, Kidner received his preparatory education at the Boston Latin School and St. Mark’s School before matriculating to Harvard College. At Harvard, he demonstrated exceptional aptitude in classical studies and the natural sciences, earning his Bachelor of Arts (A.B.) degree in 1900. He immediately entered Harvard Medical School, where he distinguished himself as an astute clinical student, graduating with his Medical Doctorate (M.D.) cum laude in 1904.

Kidner secured competitive surgical appointments in Boston’s premier teaching hospitals, serving as Surgical House Officer at Massachusetts General Hospital (MGH) from 1904 to 1905, followed by intensive specialized training at Boston Children’s Hospital. In Boston, Kidner was mentored by two preeminent founding fathers of American orthopaedic surgery: Dr. Edward Hickling Bradford, the first Professor of Orthopedic Surgery at Harvard Medical School and co-author of the seminal textbook Treatise on Orthopedic Surgery, and Dr. Joel E. Goldthwait, an international authority on spinal statics, pelvic mechanics, and non-operative functional restoration. Under Bradford and Goldthwait, Kidner mastered the meticulous evaluation of pediatric musculoskeletal deformities, surgical pathology, and the critical importance of dynamic muscle balance in stabilizing the skeleton.

Following his formal training, Kidner joined the junior faculty of Harvard Medical School as an Assistant in Orthopedic Surgery and served as an Assistant Surgical Pathologist. He received appointments to the visiting surgical staffs of Boston Children’s Hospital, Massachusetts General Hospital, and Carney Hospital. During these formative Boston years, Kidner established a reputation for rigorous clinical documentation, correlating radiographic findings with pathological specimens and functional outcomes.

Academic Appointments and Clinical Leadership

In May 1917, following the entry of the United States into World War I, Dr. Joel E. Goldthwait was commissioned by the U.S. Surgeon General to organize the historic “First Orthopedic Unit.” Composed of twenty elite American orthopaedic surgeons, this unit was deployed overseas to assist the British military in organizing comprehensive fracture services and reconstructive surgical units for Allied casualties. Kidner was commissioned as a Major in the Medical Corps of the United States Army and sailed for England.

Assigned to major military orthopaedic centers in Great Britain, including Alder Hey Military Hospital in Liverpool and the Military Orthopaedic Hospital at Shepherd’s Bush in London, Major Kidner worked under the direct supervision of Major General Sir Robert Jones, the titan of British orthopaedics. At the side of Sir Robert Jones, Kidner treated severe battlefield trauma: open compound fractures, chronic osteomyelitis, joint contractures, malunions, and peripheral nerve transections. He mastered Sir Robert’s techniques of tendon transfer, functional splinting, and organized physical rehabilitation, experiences that deeply informed his subsequent surgical philosophy.

Upon his honorable discharge and return to the United States in 1919, Kidner recognized that the rapidly expanding industrial center of Detroit, Michigan, possessed vast clinical needs and limited specialized orthopaedic infrastructure. Relocating to Detroit, Kidner was appointed Chief of Orthopaedic Surgery at the Children’s Hospital of Michigan, an institution he guided for nearly three decades into a leading center for pediatric orthopaedic care. Under his leadership, the hospital developed comprehensive clinical programs for congenital clubfoot, developmental dysplasia of the hip, tuberculosis of bones and joints, and the severe paralytic deformities of poliomyelitis.

Concurrently, Kidner was appointed Attending Orthopaedic Surgeon and Chief of the Orthopaedic Section at Harper Hospital, one of Detroit’s venerable adult voluntary hospitals, where he managed complex trauma, joint reconstruction, and spinal disorders. His national reputation in poliomyelitis management led to his appointment as Consulting Orthopaedic Surgeon to the Georgia Warm Springs Foundation, where he worked alongside President Franklin D. Roosevelt and prominent national leaders to optimize hydrotherapy and reconstructive interventions for polio survivors. Within professional societies, Kidner was a pillar of the orthopaedic community: he was elected President of the Michigan Orthopaedic Society in 1931, served on regional health boards, and maintained active fellowships in the American College of Surgeons (FACS), the American Orthopaedic Association (AOA), and the American Academy of Orthopaedic Surgeons (AAOS).

3. Core Orthopaedic Breakthroughs, Eponymous Signs & Innovations

Frederick Clinton Kidner made lasting contributions to reconstructive surgery through his ability to dissect complex clinical presentations into clear anatomical and mechanical components. His clinical insights reshaped operative approaches to congenital foot anomalies, pediatric osteochondroses, and non-operative spinal rehabilitation.

Hallmark Anatomical, Diagnostic and Operative Contributions

• The Kidner Procedure (1929, 1933): The definitive surgical reconstruction for symptomatic accessory navicular (os tibiale externum / prehallux) associated with painful flatfoot. The technique entails complete excision of the accessory ossicle, trimming of the hypertrophic navicular tuberosity flush with the medial cuneiform, and trans-osseous transposition of the posterior tibial tendon into a prepared trough on the inferior (plantar) surface of the navicular body.
• Anatomical and Biomechanical Characterization of the “Prehallux” (1929): The identification of the accessory tarsal scaphoid as a phylogenetic rudimentary first digit (prehallux) that pathologically alters the vector of the posterior tibial tendon. Kidner demonstrated that the abnormal insertion elevates the tendon’s pull, converting it from a dynamic plantar arch suspender into an ineffective horizontal adductor, thereby precipitating progressive medial longitudinal arch collapse.
• Natural History of Köhler’s Disease of the Tarsal Scaphoid (1924): A landmark clinical and radiographic investigation of 104 children with navicular osteochondrosis (os naviculare pedis retardatum), proving that the disorder is a self-limiting avascular necrosis that predictably reconstitutes full bone architecture under conservative casting, establishing that surgical intervention is unwarranted and counterproductive.
• Conservative Rehabilitation Algorithms for Low Back Pain and Sciatica (1948): A comprehensive non-operative framework published in Surgical Clinics of North America providing structured clinical pathways (postural realignment, abdominal strengthening, graded traction, and selective immobilization) that challenged the excessive surgical enthusiasm for lumbar laminectomy following the discovery of disc herniation.

The biomechanical elegance of the Kidner procedure resides in its restoration of native functional anatomy. In the normal foot, the posterior tibial tendon passes posterior and inferior to the medial malleolus, courses across the medial longitudinal arch, and inserts primarily into the plantar tuberosity of the navicular, while sending robust secondary slips to the three cuneiforms, the cuboid, and the bases of the second, third, and fourth metatarsals. This plantar insertion creates a dynamic sling: when the posterior tibial muscle contracts during the stance phase of gait, it inverts the subtalar joint, plantarflexes the midfoot, locks the transverse tarsal (Chopart) joint into rigid stability, and elevates the medial longitudinal arch, providing a rigid lever for forward propulsion.

In patients with an accessory navicular (specifically Type II, where the ossicle connects to the navicular body via a fibrocartilaginous or cartilaginous synchondrosis, or Type III, where it forms an enlarged cornuate navicular), Kidner observed that the primary mass of the posterior tibial tendon terminates abnormally on the medial and dorsal aspect of the accessory bone. Consequently, the tendon fails to reach the inferior aspect of the navicular and cannot send its normal dynamic plantar expansions across the sole of the foot. Under muscle contraction, the tendon pulls horizontally and proximally across the medial malleolus, adducting the forefoot against the hindfoot without exerting any upward lift on the arch. The medial arch loses its dynamic muscular suspension, transferring excessive mechanical load to the static spring (plantar calcaneonavicular) ligament and deltoid ligament complex. Over time, these static soft tissues stretch, the talar head drops plantarly and medially, and a flexible flatfoot deformity ensues, compounded by focal bursitis and chronic synchondrosis microfracture from footwear friction.

Kidner’s operative procedure corrects both the mechanical vector and the osseous impingement. Approaching through a curved medial incision over the navicular, the surgeon splits the posterior tibial tendon longitudinally, shells out the accessory bone, and resects the prominent medial navicular tuberosity flush with the medial cortical boundary of the adjacent medial cuneiform and anterior talus. Rather than reattaching the tendon to the raw medial bone, Kidner channeled the tendon directly into a surgically excavated groove on the plantar surface of the navicular body, securing it under tension with trans-osseous sutures while the foot is held in inversion. This trans-osseous plantar transposition re-establishes the inferior pulley mechanism, enabling every subsequent contraction of the posterior tibial muscle to actively suspend the medial longitudinal arch.

Kidner’s 1924 publication in the Journal of the American Medical Association, co-authored with Dr. F. Muro, stands as another milestone in orthopaedic scholarship. At a time when localized radiographic changes in pediatric bones were frequently attributed to tuberculosis, osteomyelitis, or syphilis, leading to aggressive curettage or arthrodesis, Kidner and Muro assembled 104 cases of tarsal scaphoid flattening and sclerosis (Köhler’s disease). Through serial radiographic documentation and clinical follow-up, they established that this condition represents a benign, self-limiting osteochondrosis of the navicular ossification center. They showed that protected immobilization in a walking plaster cast or supportive footwear until pain subsides consistently results in complete spontaneous revascularization, re-expansion, and normal bone modeling, without any permanent functional deficit or joint arthrosis. This landmark paper remains one of the definitive historical validations of conservative watchful waiting in pediatric orthopaedics.

In his 1948 monograph, “Low back pain and sciatica from a conservative standpoint,” Kidner applied the same philosophy of biological restraint to adult spinal disorders. Following the 1934 publication by Mixter and Barr identifying lumbar disc herniation as the primary cause of sciatica, an international surgical trend emerged in which exploratory laminectomy and spinal fusion were performed with increasing frequency for ordinary low back pain. Kidner emphasized that over eighty percent of patients with lumbosacral pain and sciatica achieve full functional recovery without operative intervention through systematic conservative therapy: temporary bed rest, pelvic traction, graduated hyperextension and abdominal strengthening exercises, postural re-education, and temporary supportive bracing. He cautioned against surgical intervention in the absence of objective, progressive motor deficits or sphincter dysfunction, anticipating the modern evidence-based paradigm that reserves spine surgery for clearly defined neurocompressive emergencies or failed exhaustive conservative care.

4. Master Class Pro-Tip

1. Precise Navicular Tuberosity Resection Margin: When excising a symptomatic Type II or Type III accessory navicular, ensure that the medial tuberosity of the navicular is resected flush with the medial cortical margin of the adjacent medial cuneiform and anterior talus. Never leave a residual medial prominence that will continue to cause footwear impingement. Crucially, do not carry the osteotome or saw blade too far laterally or posteriorly: always directly visualize the talonavicular joint capsule and preserve the articular cartilage of the acetabulum pedis. Violation of the talonavicular articular facet creates chondral scarring, early post-traumatic arthrosis, and persistent midfoot pain.

2. Creation of the Plantar Navicular Trough and Transposition: To convert the vector of the posterior tibial tendon (PTT) from an ineffective horizontal pull into an active dynamic plantar sling, elevate the periosteal sleeve plantarly and prepare a cancellous trough on the inferior aspect of the navicular body using a small rongeur or burr. The mobilized PTT must be re-routed directly through this sub-navicular trough rather than merely repaired side-to-side on the medial cortex. This anatomical re-routing restores the tendon’s biomechanical lever arm beneath the midfoot arch.

3. Trans-Osseous Fixation Under Inversion Tension: Anchor the transposed PTT into the plantar navicular trough using heavy, non-absorbable trans-osseous sutures passed through drill holes exiting dorsomedially, or utilize modern threaded suture anchors. Secure the tendon under robust physiological tension while an assistant maintains the hindfoot in moderate inversion and slight plantarflexion. Maintain this corrective position in a well-molded, non-weight-bearing plaster splint or cast postoperatively for 4 to 6 weeks to permit solid osseotendinous healing before initiating progressive protected weight-bearing.

4. Differentiating Isolated Accessory Navicular from Structural Pes Planus: An isolated Kidner procedure reliably relieves focal medial prominence pain and restores active inversion in patients with flexible, symptomatic accessory naviculars. However, it will fail if applied in isolation to patients with rigid structural flatfoot, severe heel valgus exceeding 10 to 12 degrees, significant peritalar subluxation, or fixed forefoot supination. In such advanced structural deformities, excessive mechanical tension across the reconstructed medial column will inevitably stretch out the transferred PTT. In these clinical scenarios, the Kidner procedure must be augmented with structural bony corrections, such as a medializing calcaneal osteotomy (Evans or Dwyer), a lateral column lengthening, or a Cotton opening wedge medial cuneiform osteotomy.

Master Class Surgical Pearl: Technical Nuances of the Kidner Procedure and Navicular Reconstruction

5. Primary Landmark Publications & Bibliography

The foundational contributions of Frederick Clinton Kidner are preserved in these original landmark monographs and peer-reviewed surgical literature:

• Kidner FC. The prehallux (accessory scaphoid) in its relation to flat-foot. J Bone Joint Surg Am. 1929;11(4):831–837.
• Kidner FC. The prehallux in relation to flatfoot. JAMA. 1933;101(20):1539–1542. DOI
• Kidner FC, Muro F. Köhler’s disease of the tarsal scaphoid or os naviculare pedis retardatum. JAMA. 1924;83(21):1650–1654. DOI
• Kidner FC. Low back pain and sciatica from a conservative standpoint. Surg Clin North Am. 1948;28(5):1233–1246. DOI | PubMed
• In Memoriam. Frederick Clinton Kidner 1879–1950. J Bone Joint Surg Am. 1951;33-A(2):538–539. DOI
• Kim JR, Park CI, Moon YJ, Wang L, Liu Y. Concomitant calcaneo-cuboid-cuneiform osteotomies and the modified Kidner procedure for severe flatfoot associated with symptomatic accessory navicular in children and adolescents. J Orthop Surg Res. 2014;9:131. DOI
• Sands AK. Painful Accessory Navicular: Augmented Kidner Procedure with Flexor Digitorum Longus Transfer. Oper Tech Foot Ankle Surg. 2010:135–144. DOI
• Mostofi SB, ed. Who’s Who in Orthopedics. London: Springer-Verlag; 2005:175.

6. Biographical Provenance & Acknowledgments

This historical biography was synthesized for the OrthopaedicsOne Knowledge Network as part of A Who’s Who of Orthopaedics, adapted and expanded from the foundational biographical directory Who’s Who in Orthopedics (Springer-Verlag London) edited by Seyed B. Mostofi, BSc, MBBS, FRCS (Ed).