Evaluation of Articular Surface Similarity of Hemi-Hamate Grafts and Proximal Middle Phalanx Morphology: A 3D Geometric Morphometric Approach

Comparison of hamate versus second or third toe osteochondral graft using magnetic resonance imaging for reconstruction of proximal interphalangeal fracture-dislocations

Hemi-hamate arthroplasty is a method used to reconstruct complex fracture-dislocations of the proximal interphalangeal joint of the fingers. Other graft sites, including the toe second and third phalanges, have been proposed as alternatives to hemi-hamate arthroplasty due to variable clinical outcomes and anatomy. Through a prospective magnetic resonance imaging (MRI)-based study in asymptomatic individuals, we aimed to characterize the anatomy of the proximal interphalangeal joint and compare this with the hamate, second and third toes to determine the closest anatomical match using pre-determined measurements. Our results show that the second and third toes have greater anatomical similarity to the proximal interphalangeal joint of the fingers compared to the hamate. High-resolution MRI is a reliable method of characterizing the anatomy of these structures and could be a useful clinical tool in determining reconstructive options in the management of this challenging injury.Level of evidence: II.

Free hemi-hamate arthroplasty: A review of donor site outcomes

Introduction

The use of the dorsal hamate as a free osteochondral bone graft or vascularized bone flap has become the mainstay for large, comminuted middle phalanx volar lip fractures. To date, few studies have been conducted in the assessment of donor site morbidity for the hemi-hamate graft or flap, and none have discussed modes of repair or reconstruction of this donor site.

Methods

A retrospective analysis of 14 hemi-hamate arthroplasty (HHA) procedures, including 6 vascularized and 8 non-vascularized grafts, from two surgeons was performed. Four hamate defect reconstruction techniques were utilized: no formal reconstruction, autologous bone grafting, gel foam, or synthetic bone substitute. The dorsal capsule was repaired with either extensor retinaculum grafting or by direct closure. Wrist range of motion, pain scores, and radiographic alignment were assessed.

Results

At 6 months follow-up, all patients achieved full, pain-free wrist motion compared to the uninjured side, with visual analog scale pain scores of 0. Serial radiographs showed maintained carpal alignment without instability or subluxation. No differences based on the hamate defect reconstruction method or capsular repair technique was demonstrated.

Conclusion

Safe return to pain free, unrestricted wrist function is achievable after HHA, regardless of hamate donor site management. Adequate dorsal capsular repair appears critical to prevent instability. Further study is needed to compare techniques, but choice may be guided by surgeon preference in the absence of clear evidence.

Hemi-capitate Arthroplasty for Dorsal Fracture-Dislocations of the Proximal Interphalangeal Joint: Surgical Technique and Illustrative Case

Osteochondral graft from the carpal bone allows anatomical joint reconstruction in unstable dorsal fracture-dislocations with > 50% of the articular surfaces. The most used graft is the dorsal hamate. Hemi-hamate arthroplasty is technically challenging and has anatomical incongruity, and many authors have evolved various modifications in the palmar buttress reconstruction of the middle phalanx base. Therefore, there are no universally accepted treatment modalities for these complex articular injuries. This article describes the dorsal capitate as the osteochondral graft for middle phalanx volar articular surface reconstruction. Hemi-capitate arthroplasty was done on a 40-year-old man with an unstable dorsal fracture dislocation of the PIP joint. The osteochondral capitate graft united well, and the joint congruency was good at the final follow-up. The surgical technique, illustrative images, and rehabilitation are discussed. With the evolving technical modifications and complications in Hemi-hamate arthroplasty, distal capitate may be considered a reliable and alternate osteochondral graft for unstable PIP joint fracture-dislocations.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-023-00853-2.

Hemihamate Arthroplasty Revisited: A Retrospective Review of 11 Cases

PURPOSE

Proximal interphalangeal joint (PIPJ) fracture dislocations are complex injuries that can result in persistent pain, stiffness, and angulation. Hemihamate arthroplasty (HHA) can be used to reconstruct the base of the middle phalanx in cases of unstable PIPJ fracture dislocations. Despite previous case series describing good outcomes with HHA, it has not gained widespread use. The purpose of this study is to describe our straightforward, reproducible technique and to demonstrate the benefit in motion after the procedure in chronic unstable PIPJ fracture dislocations.

METHODS

All patients with chronic, unstable PIPJ fracture dislocations requiring joint resurfacing of greater than 40% of the base of the middle phalanx treated with HHA were retrospectively reviewed. Patient demographics, injury features, surgical technique, preoperative and postoperative PIPJ range of motion and arc of motion, time to surgery, and complications were reviewed. Any fracture amenable to fixation or cases with radiographic evidence of arthritis or injury to the head of the proximal phalanx were excluded.

RESULTS

Eleven cases were reviewed. The mean patient age was 35 years. The mean time from injury to surgery was 6 months. The mean joint surface involved was 64%. The mean PIPJ arc of motion was 17 degrees preoperatively and 63 degrees postoperatively. The mean bone block size required was 8 × 8 × 8 mm. The mean follow-up was 26 months. Postoperative pain at the PIPJ on the visual analog scale was 0.4 (scale of 0 to 10). Complications included 2 patients requiring tenolysis.

CONCLUSIONS

Despite the lack of a perfect geometric recreation of the base of the middle phalanx with the hamate, patients recover acceptable PIPJ motion and have minimal pain. Hemihamate arthroplasty is a good option for any patient with minimal motion of their PIPJ and a chronic, unstable fracture dislocation.

Hamate vs. capitate grafting for proximal interphalangeal joint fracture-dislocation: an MRI-based study of 35 hands

We examined the MRI scans of 35 adult hands to assess the feasibility of the hamate and the capitate as potential donor grafts in the management of comminuted intra-articular fractures at the base of the middle phalanges. Essentially neither the hamate nor the capitate were perfect anatomic matches in most digits, but the capitate had the advantage of having more uniform facets, and the capitate facet shapes were similar to those of the little finger. The measurement of angles in the coronal and sagittal plane showed that in some respects the differences between the potential graft and the base of the middle phalanges were smaller for the capitate than for the hamate. Moreover, the sagittal morphology of the capitate made it less prone to joint overstuffing than the hamate. We conclude that the capitate may be considered as a graft donor in selected cases, especially for the little finger.

Assessment of grip-motion characteristics in carpal tunnel syndrome patients using a novel finger grip dynamometer system

Background

Grip strength measurement is widely used in daily medical practice, and it has been reported that the grip strength decreases in patients with carpal tunnel syndrome (CTS). However, conventional grip dynamometers evaluate only the maximum power of total grip strength and cannot measure the time course of grip motion. In this report, we aimed to determine the grip characteristics of CTS patients by measuring the time course of each finger’s grip motion and to analyze the relationship between finger grip strength and subjective symptoms using this new grip system.

Methods

The grip strength of each finger was measured using the new grip system that has four pressure sensors on the grip parts of each finger of the Smedley grip dynamometer. We analyzed the time course of grip motion and relationship between finger grip strength and subjective symptoms in 104 volunteer and 51 CTS hands. The Japanese Society for Surgery of the Hand version of the Carpal Tunnel Syndrome Instrument (CTSI-JSSH) and the Disability of Arm, Shoulder, and Hand questionnaire (DASH) were used as subjective evaluation scores.

Results

In the CTS group, the grip time with the index, middle, and ring fingers was longer, and the time at which strength was lost after reaching the maximum was earlier. Patients with severe subjective symptoms tended to not use the index and middle fingers during grip motion.

Conclusions

This new system that measures each finger’s grip strength at one time and record the time course of grip motion could quantify a patient’s symptoms easily and objectively, which may contribute to the evaluation of hand function.

An Analysis of Hamate Morphology Relevant to Hemi-Hamate Arthroplasty

PURPOSE

Dorsal fracture-dislocations of the proximal interphalangeal (PIP) joint can lead to joint incongruity from loss of the buttress function of the middle phalanx volar base. Hemi-hamate arthroplasty can reconstruct the volar articular surface of the middle phalangeal base where repair is not possible. We compared the anatomy of the hamate graft with the middle phalanx base.

METHODS

Forty unique skeletal specimens (40 hamates, 160 middle phalanges) were sampled. Anatomical features relevant to hemi-hamate reconstruction were measured, including the articular surface areas, the axial ridge angles, and the sagittal inclination angles of the hamate and the middle phalanx base specimens. Facets of the articular surfaces were classified as concave, convex, or flat. Calibrated measurements were made using digital photographs of the cadaveric specimens. Descriptive and univariate statistics were performed.

RESULTS

There was greater variability in the distal hamate than in the middle phalanx base. The ring finger facet of the distal hamate was concave in 39 of 40 specimens, whereas the little finger facet was convex in 31 of 40 specimens. The hamate axial ridge angle (66.0° ± 3.7°) was significantly different from the middle phalanx base (90.4° ± 0.4°). The hamate articular sagittal inclination (3.2° ± 4.1°) was significantly different from the middle phalanx base (51.2° ± 1.3°). The hamate articular surface area (1.96 cm²) was significantly greater than the middle phalanx base (mean index/middle/ring finger = 0.85 cm² and mean little finger = 0.59 cm²).

CONCLUSIONS

The distal articular surface of the hamate is not anatomically identical to the middle phalanx base. The differences may still preclude anatomical reconstruction in the setting of a dorsal PIP fracture-dislocation, thereby affecting short- and long-term outcomes.

CLINICAL RELEVANCE

Knowledge of the anatomical differences between the distal hamate and the middle phalanx base may improve graft harvest and inset during reconstruction.

Topographical Analysis of the Hamate for Proximal Pole Scaphoid Nonunion Reconstruction

PURPOSE

To quantify the similarity of the surface topography of the proximal hamate and proximal pole of the scaphoid for nonunion reconstruction.

METHODS

Using previously acquired computed tomographic scans of the wrist of 10 patients, the 2 bones were segmented and subsequently aligned using both a manual and automated technique. Surface error between corresponding articular surfaces was computed to determine the similarity of the shape of the 2 bones.

RESULTS

The median distance between the 2 articulating surfaces for each patient was 1 mm or less for all cases. Maximum distance varied from 2.7 to 9.7 mm. The automated method improved alignment such that the maximum distance was 4.1 mm. Visual review of the alignment revealed that the maximum error occurred on or around the margin of the articulating surfaces.

CONCLUSIONS

In most cases, the proximal hamate appears to be a suitable donor match to reconstruct proximal pole scaphoid nonunions.

CLINICAL RELEVANCE

This study serves as a guide to practitioners when considering the suitability of the proximal hamate autograft for unsalvageable proximal pole scaphoid nonunions.

Modeling the Articular Surface of the Hamate with the Fourth and Fifth Metacarpal Bases with Three-dimensional Laser Scanning

Introduction

Our purpose is to highlight the articulating surfaces between the hamate and fourth and fifth metacarpal (MC) bases of the hand using three- dimensional (3D) laser scanning. This joint surface is used for osteochondral grafting of small joints such as the proximal interphalangeal joint using the hamate articular surface. It is an important joint for hand function and can develop osteoarthritis. 

Methods

NextEngine (NextEngine, Santa Monica, CA) 3D laser scanner (accurate to ±100 µm) was used to capture the articular surfaces of the hamate with the fourth and fifth MC bases of 10 embalmed cadaver right hands. Articular surfaces were defined and modeled using Amira (Visage Imaging, Andover, MA) and MatLab7 (MathWorks, Natick, MA). Articular surfaces were evaluated in terms of size, shape, the radius of curvature (ROC) by three points and sphere-fit (SF) and inter-facet angles.

Results

In the fourth carpometacarpal (CMC) joint, the hamate articular surface with the 4th MC was single, concave, and well approximated by SF ROC (mean: 11.18 mm). The fourth MC base was convex; SF ROC mean was 9.94 mm. Six of the 10 articulations flattened from volar to dorsal.

In the fifth CMC joint, we noted a bicondylar construct. The two hamate surfaces were concave while MC bases were convex. The joint surface was best approximated with two overlapping spheres. Ulnar sphere averaged 30.21% of the surface of the hamate and 29% of the MC base. Ulnar hamate SF ROC mean was 11.63 mm, and ulnar fifth MC SF ROC mean was 8.07 mm. Radial SF hamate mean was 7.92 mm, and the radial fifth MC SF mean was 7.47 mm. The mean of the angle of divergence between the condylar spheres represented on the hamate surface was 21.4°, while that of the fifth MC base angle of divergence was 10.99°.

The mean of the angle formed between the fourth and fifth CMC joints at the hamate was 31.69°. A single articular facet between the fourth and fifth MC bases was concave on fourth and convex on the fifth MC base.

Conclusions and clinical relevance

Laser scanning of cadaver fourth and fifth CMC joints clarified the normal anatomy of the osteochondral joint surface. The topography of the joints was well-approximated by SF with curved surfaces in both the anteroposterior and radial-ulnar planes with the fifth CMC having two unique surfaces for articulation. We noted the distinct radial and ulnar articulating surfaces of the fifth CMC joint, which would permit flexion and limited supination.

The Relationship Between Hemihamate Graft Size and Proximal Interphalangeal Joint Flexion for Reconstruction of Fracture-Dislocations: A Biomechanical Study

PURPOSE

The purpose of this study was to determine the relationship between hemihamate graft size and proximal interphalangeal (PIP) joint flexion in a biomechanical fracture-dislocation model.

METHODS

We simulated middle finger PIP fracture-dislocations in 5 cadaver hands by resecting 50% of the palmar articular surface of the middle phalanx (P2) base. Fluoroscopy was used to confirm dorsal subluxation of the middle phalanx base after resection. A 10-mm osteochondral hamate graft was contoured to reconstruct the volar lip of the middle phalanx and was progressively downsized by 2-mm increments for each trial. A computer-controlled articulator and jig simulated active flexion and extension of the fingers. Maximum PIP flexion was measured at each graft size using fluoroscopy and digital imaging software. Clinically significant flexion block was defined as PIP flexion less than 90°.

RESULTS

The actual mean size of the volar defect created was 52% (3.5 mm) of the middle phalanx articular surface, which created instability and dorsal subluxation in all tested fingers. After hemihamate reconstruction, all specimens were stable throughout flexion and extension for all graft sizes. A flexion block of 90° occurred at a mean graft size of 191% of the defect (6.5 mm). With regard to the volar lip of the P2, grafts that projected an average 0.8 mm past the native volar lip position had 98° (range, 84°-107°) maximum PIP flexion. Grafts that projected an average of 3.1 mm past the native volar lip position had 90° (range, 69°-100°) maximum PIP flexion. Linear regression modeling incorporating all of the results predicted flexion block to occur at a graft size as small as 166% of the 50% volar P2 defect. In this model, for every 50% (1.7-mm) increase in graft size relative to the defect, PIP flexion decreased by approximately 6°.

CONCLUSIONS

Nonanatomical hemihamate grafts produce a PIP flexion block at extreme sizes, predicted to occur at greater than 166% of a 50% P2 base articular defect in our model. This suggests that relatively large grafts can be used for reconstruction of PIP fracture-dislocations without substantial biomechanical block to PIP flexion. We suggest sizing no larger than 3 mm past the native P2 volar lip position to avoid an important mechanical block to PIP flexion.

CLINICAL RELEVANCE

The information from this study helps surgeons understand how large a hemihamate graft can be used for P2 volar base reconstruction before having a negative impact on PIP flexion.